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Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 20 March 1997. Epidemiology and control of rabies. The growing problem of rabies in Africa
Abstract
Although rabies in Africa is relatively insignificant in terms of human mortality, the disease is still relevant because of the high costs of rabies prevention. Over the past 2 decades, demographic, economic and sociopolitical trends in Africa have increasingly favoured the persistence and spread of rabies, while limiting the effectiveness of control measures. Dog rabies predominates throughout most of Africa; the domestic dog is the principal reservoir host as well as the most important source of infection for people. However, wild-life rabies is increasingly a concern, both as a threat to endangered wildlife populations and because of the possible emergence of new maintenance hosts.
... A rapid growth of the dog population in combination with high birth and death rates which is typical for eg. African dog populations, generates new susceptible animals for the infection to maintain within the population (Cleaveland, 1998). In developed countries rabies is mainly preserved in wild animals (WHO, Rabies, 2008). ...
... Since the reference is inadequate this study has not been found and the reliabilty is unknown. However this shows that there is only little knowledge about the dog population in Malawi, but it also indicates high birth and death rates, which is common for African dog populations (Cleaveland, 1998). It also indicates that most dogs are owned with some but limited human supervision. ...
The aim of the study was to look into the implementation of guidelines of dog population management (DPM), published by WHO & WSPA, ICAM-coalition and OIE, in Malawi and Peru. Fieldstudies with interviews with representatives of authorities, international organizations and local NGOs were conducted in these two countries. The conclusions from the inteviews were that guidelines are only partially implemented in both countries, but the problems differ in between. No comprehensive national plan for DPM exist in either country and there are no executive group taking full responsibility. In Malawi a NGO have taken the responsibilty to try to pilot a program and involve authorities to coordinate and harmonize there work. However, lack of information about the dog population and the rabies situation as well as lack of resources, makes it very difficult to succeed with DPM. Insufficient information also makes it difficult to evaluate any rabies vaccination program. In Peru on the other hand, they have good knowledge about the number of dogs and have also succeeded very well in rabies control. Even if they lack an executive working group, they have a legisltaion supporting DPM and a direction working with eg. education programs for children. They have a comprehensive rabies program which shows that rabies control is indeed possible but instead they have other problems with diseases as echinococcosis. In both countries reproduction control is totally dependent on the work done by NGOs. The need is overwhelming and cost-benefit analysis very important when resources are limited.
... Throughout the world, including Africa, dogs are by far the most important source of infection to humans (Fekadu 1993; Edelsten 1995; Haupt 1999; Kamoltham et al. 2003; Kayali et al. 2003). The incidence of human rabies appears to be increasing in many areas, despite deteriorating detection rates and reporting systems (Cleaveland 1998); this is likely to be related, in part, to the rapid growth rate of dog populations, which in many parts of Africa exceeds that of human populations (de Balogh et al. 1993; Cleaveland 1998; Kitala et al. 2001). The implications for the dynamics of rabies are likely to be profound, resulting in an increase in the size of rabies outbreaks, the probability of disease persistence, and the likelihood of dog-to-human transmission. ...
... Throughout the world, including Africa, dogs are by far the most important source of infection to humans (Fekadu 1993; Edelsten 1995; Haupt 1999; Kamoltham et al. 2003; Kayali et al. 2003). The incidence of human rabies appears to be increasing in many areas, despite deteriorating detection rates and reporting systems (Cleaveland 1998); this is likely to be related, in part, to the rapid growth rate of dog populations, which in many parts of Africa exceeds that of human populations (de Balogh et al. 1993; Cleaveland 1998; Kitala et al. 2001). The implications for the dynamics of rabies are likely to be profound, resulting in an increase in the size of rabies outbreaks, the probability of disease persistence, and the likelihood of dog-to-human transmission. ...
Rabies is a global problem, although it is often under-reported in developing countries. We aimed at describing the profile of patients presenting to health centres with animal bite injuries in Uganda, and use a predictive model to estimate the mortality of rabies at a national level.
We conducted a passive surveillance study in Uganda based in a random sample of health centres supplied with rabies vaccine to determine the characteristics of bite injury patients and establish the age and sex profiles of patients, the site of bites and their severity, wound management techniques and details of the vaccination course given. We also applied a decision tree model to the data to estimate the rabies mortality from the bite injury data using an established protocol.
We found that most patients are bitten by dogs, and that a considerable proportion of these are young children, who are at greater risk of developing rabies in the absence of treatment due to the location of the bites they receive. From conservative parameter estimates, we estimate that in the absence of post-exposure prophylaxis (PET), 592 (95% CI 345-920) deaths would occur, and that if one dose of PET is sufficient for protection following a rabid animal bite, 20 (95% CI 5-50) deaths would occur annually. If a complete course of PET is required for protection following a rabid animal bite, up to 210 (95% CI 115-359) deaths would occur, as 41% of patients did not complete their course of PET.
Active animal bite surveillance studies are required to improve our mortality estimates and determine the true burden of rabies in the Ugandan population. We emphasize the need for small-scale active case detection studies and improved data on the recognition of rabies in dogs as inputs for improving national-level estimates of rabies mortality.
... These results are similar to those reported in a previous cross-sectional study which showed that the burden of animal bites in Uganda is considerable [21]. Although some studies have documented increasing human and dog populations as possible explanations for the increas- ing incidence of animal bites [30], the role played by these factors in Uganda is unknown. Uganda conducted a livestock census in 2008 which estimated a dog population of 1.6 million dogs country wide [29] but to our knowledge, no follow-up survey has ever been conducted to update dog statistics or predict growth rates. ...
Background
In the absence of accurate data on trends and the burden of human rabies infection in developing countries, animal bite injuries provide useful information to bridge that gap. Rabies is one of the most deadly infectious diseases, with a case fatality rate approaching 100%. Despite availability of effective prevention and control strategies, rabies still kills 50,000 to 60,000 people worldwide annually, the majority of whom are in the developing world. We describe trends and geographical distribution of animal bite injuries (a proxy of potential exposure to rabies) and deaths due to suspected human rabies in Uganda from 2001 to 2015.
Methods
We used 2001–2015 surveillance data on suspected animal bite injuries, collected from health facilities in Uganda. To describe annual trends, line graphs were used and linear regression tested significance of observed trends at P<0.05. We used maps to describe geographical distribution of animal bites by district.
Results
A total of 208,720 cases of animal bite injuries were reported. Of these, 27% were in Central, 22% in Eastern, 27% in Northern and 23% in Western regions. Out of 48,720 animal bites between 2013 and 2015, 59% were suffered by males and 81% were persons aged above 5 years. Between 2001 and 2015, the overall incidence (per 100,000 population) of animal bites was 58 in Uganda, 76 in Northern, 58 in Central, 53 in Western and 50 in Eastern region. From 2001 to 2015, the annual incidence (per 100,000 population) increased from 21 to 47 (P = 0.02) in Central, 27 to 34 (P = 0.04) in Eastern, 23 to 70 (P = 0.01) in Northern and 16 to 46 (P = 0.001) in Western region. A total of 486 suspected human rabies deaths were reported, of which 29% were reported from Eastern, 28% from Central, 27% from Northern and 17% from Western region.
Conclusion
Animal bite injuries, a potential exposure to rabies infection, and mortality attributed to rabies infection are public health challenges affecting all regions of Uganda. Eliminating rabies requires strengthening of rabies prevention and control strategies at all levels of the health sector. These strategies should utilize the “One Health” approach with strategic focus on strengthening rabies surveillance, controlling rabies in dogs and ensuring availability of post exposure prophylaxis at lower health facilities.
... The owned-dog population turnover rate in Haiti was 32%, a finding that would likely be higher had other sectors of the dog population been assessed. This finding was consistent with ecological studies on dogs in similar developing countries in Africa and Latin America (Cleaveland, 1998;Kitala et al., 2001;Acosta-Jamett et al., 2010;Davlin and Vonville, 2012). Nearly a quarter of the dog deaths recorded in this study were preventablethe result of intentional killings, often through suspected poisonings. ...
An estimated 59 000 persons die annually of infection with the rabies virus worldwide, and dog bites are responsible for 95% of these deaths. Haiti has the highest rate of animal and human rabies in the Western Hemisphere. This study describes the status of animal welfare, animal vaccination, human bite treatment, and canine morbidity and mortality in Haiti in order to identify barriers to rabies prevention and control. An epidemiologic survey was used for data collection among dog owners during government-sponsored vaccination clinics at fourteen randomly selected sites from July 2014 to April 2015. A total of 2005 surveys were collected and data were analysed using parametric methods. Over 50% of owned dogs were allowed to roam freely, a factor associated with rabies transmission. More than 80% of dog owners reported experiencing barriers to accessing rabies vaccination for their dogs. Nearly one-third of the dog population evaluated in this study died in the year preceding the survey (32%) and 18% of these deaths were clinically consistent with rabies. Dog bites were commonly reported, with more than 3% of the study population bitten within the year preceding the survey. The incidence of canine rabies in Haiti is high and is exacerbated by low access to veterinary care, free-roaming dog populations and substandard animal welfare practices. Programmes to better understand the dog ecology and development of methods to improve access to vaccines are needed. Rabies deaths are at historical lows in the Western Hemisphere, but Haiti and the remaining canine rabies endemic countries still present a significant challenge to the goal of rabies elimination in the region.
... Although all species of mammals are susceptible to rabies virus infection, only a few species are important as reservoirs of infection [3]. The most common route of rabies transmission to humans is the bite of rabid domestic dogs [4]. The WHO considers that canine rabies potentially threatens over three billion people in Asia and Africa [5]. ...
Background
Although rabies represents an important public health threat, it is still a neglected disease in Asia and Africa where it causes tens of thousands of deaths annually despite available human and animal vaccines. In the Central African Republic (CAR), an endemic country for rabies, this disease remains poorly investigated.
Methods
To evaluate the extent of the threat that rabies poses in the CAR, we analyzed data for 2012 from the National Reference Laboratory for Rabies, where laboratory confirmation was performed by immunofluorescence and PCR for both animal and human suspected cases, and data from the only anti-rabies dispensary of the country and only place where post-exposure prophylaxis (PEP) is available. Both are located in Bangui, the capital of the CAR. For positive samples, a portion of the N gene was amplified and sequenced to determine the molecular epidemiology of circulating strains.
Results
In 2012, 966 exposed persons visited the anti-rabies dispensary and 632 received a post-exposure rabies vaccination. More than 90% of the exposed persons were from Bangui and its suburbs and almost 60% of them were under 15-years of age. No rabies-related human death was confirmed. Of the 82 samples from suspected rabid dogs tested, 69 were confirmed positive. Most of the rabid dogs were owned although unvaccinated. There was a strong spatiotemporal correlation within Bangui and within the country between reported human exposures and detection of rabid dogs (P<0.001). Phylogenetic analysis indicated that three variants belonging to Africa I and II lineages actively circulated in 2012.
Conclusions
These data indicate that canine rabies was endemic in the CAR in 2012 and had a detrimental impact on human health as shown by the hundreds of exposed persons who received PEP. Implementation of effective public health interventions including mass dog vaccination and improvement of the surveillance and the access to PEP are urgently needed in this country.
... Rabies has been observed in wildlife populations throughout Africa with devastating effects in some regions. A rabies outbreak in the early 1990s decreased the Ethiopian wolf population to only 400 animals and the wild dog population has also decreased markedly (S Cleaveland, 1998). In the Madikwe Game Reserve in the Northwest province of South Africa only three members of a pack of wild dogs survived a rabies outbreak (M Hofmeyr et al., ). ...
Two dog rabies epidemics have occurred in Kwazulu Natal, a province on the eastern seaboard of South Africa. The first occurred in 1964 but was brought under control. The second started in 1976 at the same time as a civil war outbreak in Mozambique which lead to refugees fleeing into South Africa. During this second epidemic rabies spread further into adjacent regions. Rabies is endemic in domes-tic dogs in Kwazulu Natal but spillovers to wildlife species have occurred. Two biotypes of the rabies virus (genotype 1) have been identified in southern Africa, the canid-and the mongoose-biotype. It has also been found that geographical location influences the clusters that form when constructing phylogenetic trees. Of the other lyssaviruses Lagos Bat virus (genotype 2) and Mokola virus (genotype 3) has been reported in Kwazulu Natal. Duvenhage virus (genotype 4) has also been reported but from other regions of South Africa. Recently the number of wildlife rabies cases from Kwazulu Natal has increased. Samples from Kwazulu Natal including canine, bovine and other wild animals like fox, jackal and mongoose samples were analyzed. The samples were first tested using the fluorescent antibody test (FAT) and RNA ex-traction was performed on samples that tested positive. This was followed by reverse transcription, PCR and sequencing of the G-L intergenic region. A phylogenetic tree was constructed using these sequences. Sequences obtained from Kwazulu Natal isolates in previous years were also included in the analyses. The epidemiological analysis of the samples will give an indication of the virus cycles in Kwazulu Natal. If the sequences are compared to those from neighbouring countries, viral cycles in southern Africa can be determined. This study will also detect rabies related viruses of which the char-acterisation is important for the implementation of control measures.
... Therefore, a relatively small change in coverage could determine whether control succeeds or fails. Because many campaigns fail to reach 70% (Cleaveland 1998), rabies eradication may be unlikely when using vaccination alone. ...
�Context:� Rabies causes ~55 000 human deaths each year, primarily as a result of bites from dogs, which are the major rabies reservoir in the developing world. Current rabies control strategies include vaccination, culling and surgical sterilisation of dogs. However, recently developed immunocontraceptives could be used alongside vaccination to apply fertility control to more animals.
�Aims:� We used a modelling approach to explore (1) whether adding single-dose contraceptives to rabies vaccination would improve effectiveness of rabies eradication, (2) how sensitive control methods are to variation in population parameters and (3) the effects of applying control continuously or in pulses on rabies eradication.
�Methods:� A continuous time, compartmental model was created to describe canine rabies epidemiology. Parameters were derived from the literature. The following three control methods were applied at varying rates and durations: vaccination, vaccination plus fertility control (v + fc) and culling
... Detailed information relating to specific areas is sometimes collected, but often as a result of a response to what is seen as an emergency or crisis situation. For instance, a substantial amount of data is now available on rabies and canine distemper in wild carnivores in the Serengeti and Mara from studies that were initiated following the devastating effects of epidemics of the diseases in the 1990s (Woodroffe et al., 1997; Cleaveland, 1998). With the lack of a properly functioning and reliable surveillance system for veterinary diseases in Kenya and Tanzania, prioritising diseases for research or control will continue to be dependent largely on limited information and informed guesswork. ...
Desk-study appraisal of pastoral production potential in relation to continued interventions by the ERETO Ngorongoro pastoralist project in northern Tanzania for Danida.
... Since the 1960s, the reported incidence of canine and human rabies has increased in many countries in southern and eastern Africa [1,2] even though detection rates and reporting systems have deteriorated [3] and effective human post-exposure prophylaxis and dog rabies vaccines have become available commercially [4]. Most human rabies deaths worldwide occur in Africa and Asia, with an estimated 24 500 human deaths per year in Africa, more than 100 times the number of cases officially recorded [5]. ...
Background
Mass vaccinations of domestic dogs have been shown to effectively control canine rabies and hence human exposure to rabies. Knowledge of dog population demography is essential for planning effective rabies vaccination programmes; however, such information is still rare for African domestic dog populations, particularly so in urban areas. This study describes the demographic structure and population dynamics of a domestic dog population in an urban sub-Saharan African setting. In July to November 2005, we conducted a full household-level census and a cross-sectional dog demography survey in four urban wards of Iringa Municipality, Tanzania. The achievable vaccination coverage was assessed by a two-stage vaccination campaign, and the proportion of feral dogs was estimated by a mark-recapture transect study.
Results
The estimated size of the domestic dog population in Iringa was six times larger than official town records assumed, however, the proportion of feral dogs was estimated to account for less than 1% of the whole population. An average of 13% of all households owned dogs which equalled a dog:human ratio of 1:14, or 0.31 dogs per household or 334 dogs km-2. Dog female:male ratio was 1:1.4. The average age of the population was 2.2 years, 52% of all individuals were less than one year old. But mortality within the first year was high (72%). Females became fertile at the age of 10 months and reportedly remained fertile up to the age of 11 years. The average number of litters whelped per fertile female per year was 0.6 with an average of 5.5 pups born per litter. The population growth was estimated at 10% y-1.
Conclusions
Such high birth and death rates result in a rapid replacement of anti-rabies immunised individuals with susceptible ones. This loss in herd immunity needs to be taken into account in the design of rabies control programmes. The very small proportion of truly feral dogs in the population implies that vaccination campaigns aimed at the owned dog population are sufficient to control rabies in urban Iringa, and the same may be valid in other, comparable urban settings.
... Rabies has been observed in wildlife populations throughout Africa with devastating effects in some regions. A rabies outbreak in the early 1990s decreased the Ethiopian wolf population to only 400 animals and the wild dog population has also decreased markedly (S Cleaveland, 1998). In the Madikwe Game Reserve in the Northwest province of South Africa only three members of a pack of wild dogs survived a rabies outbreak (M Hofmeyr et al., ). ...
Human rabies is caused by viruses from the Lyssavirus genus. Only genotypes 1 and 4 have caused human rabies in South Africa. Genotype 1 can further be subdivided into canid and mongoose bio-types. Most laboratory confirmed cases of human rabies in South Africa occur in Kwa-Zulu Natal, with an additional outbreak occurring in the Limpopo province in 2006. Phylogenetic analysis of the G-L region revealed that there have been no other genotypes causing human rabies and that most of the human cases are caused by the canid biotype of genotype 1. In addition to this, the viruses grouped by location, with Eastern Cape and Kwa-Zulu Natal coastal viruses grouping together and Free State viruses grouping in this cluster as well, Mpumalanga and Kwa-Zulu Natal inland viruses grouping to-gether, and Limpopo viruses forming their own cluster. One mongoose rabies case was found, from a man bitten by a cat in the Northern Cape province.
... WCBV has not been isolated from bats in Africa, the only isolation of WCBV was from Miniopterus bats in the West Caucasus (Botvinkin et al., 2003), however a high seroprevalence of anti-WCBV antibodies was detected in African Miniopterus when the appropriate study was undertaken (Kuzmin et al., 2008b). These reports and others (Cleaveland, 1998; Knobel et al., 2005) highlight the limited understanding of lyssavirus epidemiology. Recently, Streicker et al. (2010) suggested that the phylogenic distance between bat species is an important factor in cross-species transmission and host shifts of rabies viruses in North America. ...
It is likely that phylogroup 2 lyssaviruses circulate within bat reservoirs. We adapted a pseudotype (pt) neutralisation assay (PNA) to a multiplex format enabling serosurveillance for Lagos bat virus (LBV), Mokola virus (MOKV) and West Caucasian bat virus (WCBV) in a potential reservoir, the African straw-coloured fruit bat, Eidolon helvum. Highly correlated titres were observed between single and multiplex PNAs using ptLBV and ptMOKV (r=0.97, p<0.0001), validating its use for bat serosurveillance. Of the bat serum samples screened 56% neutralised ptLBV, 27% ptMOKV and 1% ptWCBV. Mean VNAb titres were 1:266, 1:35 and 1:7 against ptLBV, ptMOKV and ptWCBV respectively. The high seroprevalence estimates suggest that the infection rate of LBV in E. helvum remains high enough to persist in this species. This supports the hypothesis that LBV is endemic in Ghanaian E. helvum and we speculate that LBV may have co-evolved with African megachiroptera.
... An increasing rabies incidence in Africa and Asia has been largely attributed to population growth of dogs. [6,21] In Tanzania, anti-rabies dog vaccine is available in most of the veterinary centers. The World Health Organization (WHO) estimates the threshold vaccination coverage for rabies eradication in dog populations at about 70% based on empirical evidence. ...
The aim of this study was to determine the incidence of humans being bitten by rabies-suspected animals, and the victims' adherence to post-exposure prophylaxis (PEP) regimen.
A retrospective analysis of data of victims treated at Bugando Medical Centre during the period 2002-2006 (n=5 years) was done.
A total of 767 bite injuries inflicted by rabies-suspected animals were reported, giving a mean annual incidence of ~58 cases per 100,000 (52.5% males, 47.5% females). The proportion of children bitten was relatively higher than that of adults. All victims were treated by using inactivated diploid-cell rabies vaccine and were recommended to appear for the second and third doses. However, only 28% of the victims completed the vaccination regime. Domestic dogs were involved in 95.44% of the human bite cases, whereas cats (3.9%), spotted hyena (Crocuta crocuta) (0.03%), vervet monkey (Cercopithecur aethiops) (0.01%) and black-backed jackal (0.01%) played a minor role. The majority of rabies-suspected case reports were from Nyamagana district and occurred most frequently from June to October each year.
In conclusion, this study revealed that incidences of humans being bitten by dogs suspected of rabies are common in Tanzania, involve mostly children, and victims do not comply with the prophylactic regimen. Rigorous surveillance to determine the status of rabies and the risk factors for human rabies, as well as formulation and institution of appropriate rabies-control policies, is required.
... The study implicated that: (1) the incidence of human rabies, which China was largely free from in the final years of the last millennium, is now increasing which should be a warning sign for control and prevention; (2) there is a need to improve the current rabies control programme in order to reduce non-compliance rates and to decrease the occurrence of flaws in the surveillance programme and in the provision of health care. Given the findings of the study, we view the implementation of the following measures as appropriate [9-12,41,42]: (a) continuing supervision of the current human rabies control programme, in order to reduce both non-compliance rates and the occurrence of flaws in health-care provision; (b) improving the interactions between professionals from the divisions of the municipal health-care network and teams of national programmes; (c) increase rabies awareness among Chinese health authorities and policymakers, improve the training of general practitioners and health care workers, and educate school children and the general public, which is crucial for effective rabies control; and (d) urban planning and development should take ecosystem preservation into account, in an attempt to balance the interaction between humans and animals. ...
Rabies is a major public-health problem in developing countries such as China. Although the recent re-emergence of human rabies in China was noted in several epidemiological studies, little attention was paid to the reasons behind this phenomenon paralleling the findings of the previous reports. The purpose of this study is thus first to characterize the current trends of human rabies in China from 1990 to 2007, and then to define better recommendations for improving the post-exposure prophylaxis (PEP) schedules delivered to rabies patients.
The most updated epidemiological data for 22527 human rabies cases from January 1990 to July 2007, retrieved from the surveillance database of reportable diseases managed by the Ministry of Health of China, were analysed. To investigate the efficiency for the post-exposure treatment of rabies, the details of 244 rabies patients, including their anti-rabies treatment of injuries or related incidents, were ascertained in Guangdong provincial jurisdiction. The risk factors to which the patients were predisposed or the regimens given to 80 patients who received any type of PEP were analysed to identify the reasons for the PEP failures.
The results from analysis of the large number of human rabies cases showed that rabies in China was largely under control during the period 1990-1996. However, there has been a large jump in the number of reported rabies cases since 2001 up to a new peak (with an incidence rate of 0.20 per 100000 people) that was reached in 2004, and where the level has remained until present. Then, we analysed the PEP in 244 rabies cases collected in the Guangdong province in 2003 and 2004, and found that 67.2% of the patients did not seek medical services or did not receive any PEP. Further analysis of PEP for the 80 rabies patients who received any type of PEP indicated that almost all of the patients did not receive proper or timely treatment on the wounds or post-exposure vaccination or rabies immunoglobulins.
While the issue of under-reporting of rabies in previous years may well be a factor in the apparent upwards trend of human rabies in recent years, the analysis of PEP in the Guangdong province provides evidence that suggests that the failure to receive PEP was a major factor in the number of human cases in China. Thus, the data underline the need for greatly improved availability and timely application of high-quality anti-rabies biologicals, both vaccines and immunoglobulins, in the treatment of human bite victims. Controlling dog rabies through pet vaccination schemes may also play a huge role in reducing the rate of human exposure. Education of the public, health care staff and veterinarians will also help to change the current situation.
... As in a classic situation, this outbreak in humans followed an outbreak in domestic dogs of the region. Increasing numbers of human rabies cases in Africa have been attributed to increasing numbers in animals, to the mobility of human and animal populations, and to deteriorating infrastructure and resources for rabies control (4,26). Reasons for the reemergence of canine rabies in Limpopo after many years of effective disease control are unclear. ...
The incidence of dog rabies in Limpopo Province, South Africa, increased from 5 cases in 2004 to 100 in 2006. Human rabies had last been confirmed in 1981, but investigations instituted after an index case was recognized in February 2006 identified 21 confirmed, 4 probable, and 5 possible human cases between August 5, 2005, and December 31, 2006. Twelve of these case-patients were identified retrospectively because the diagnosis of rabies was not considered: 6 of these patients consulted a traditional healer, 6 had atypical manifestations with prominent abdominal symptoms, and 6 of 7 patients tested had elevated liver enzyme activity. Molecular genetic analysis indicated that outbreak virus strains were most closely related to recent canine strains from southern Zimbabwe. Delayed recognition of the human cases may have resulted from decreased clinical suspicion after many years of effective control of the disease and the occurrence of atypical clinical presentations.
Background:
There is a sheer lack of knowledge in treating rabies in Pakistan. To decrease the number of victims every year, immunization and awareness programs are the basic necessities of Pakistani population. The aim of this study was to highlight the lack of learning strategies and how to overcome this problem, so as to eliminate rabies.
Methods:
This cross-sectional study was conducted on 692 respondents, aged 8-50 years, in Karachi city of Pakistan from January 2022 to June 2022. The study was based on demographic characteristics and basic knowledge of rabies, mode of transmission, clinical signs, and range of animal host species. Binary logistic regression analysis was performed to know the risk factor of rabies among different age groups, marital status, occupation, etc.
Results:
Results revealed that all the age groups were at risk of the wrong knowledge about rabies, odds = 1.182 and odds = 1.775 for 20-30 and 31-40 years of age, respectively; however, 31-40 years were at the high risk of showing odds=3.597 (95% C.I 1.621-7.983). The correlation of occupation was also checked with rabies knowledge. Only doctors (odds = 1.396) and students (odds = 1.955) showed their unawareness about rabies.
Conclusion:
This study highlights the grave situation that holds the country in the form of rabies. Through this study we aspire to raise awareness regarding the transmission, spread, and control of rabies
Rabies is a viral zoonosis that causes an estimated 59,000 preventable human fatalities every year. While more than 120 countries remain endemic for dog-mediated rabies, the burden is the highest in Africa and Asia where 99% of human rabies cases are caused by domestic dogs. One such rabies-endemic country is South Africa where an estimated 42 preventable human deaths occur every year. Although canine rabies had been well described for most of the provinces in South Africa, the epidemiology of rabies within the North West Province had not been well defined prior to this investigation. As such, the aim of this study was to use nucleotide sequence analyses to characterise the extant molecular epidemiology of rabies in the North West Province of South Africa—with specific focus on the interface between dogs and sylvatic species. To this end, Rabies lyssavirus isolates originating from the North West Province were subjected to molecular epidemiological analyses relying on the Bayesian Markov Chain Monte Carlo methodology on two distinct gene regions, viz. the G-L intergenic region and partial nucleoprotein gene. Our results provided strong evidence in support of an endemic cycle of canine rabies in the East of the province, and three independent endemic cycles of sylvatic rabies spread throughout the province. Furthermore, evidence of specific events of virus spill-over between co-habiting sylvatic species and domestic dogs was found. These results suggest that the elimination of canine-mediated rabies from the province will rely not only on eliminating the disease from the dog populations, but also from the co-habiting sylvatic populations using oral rabies vaccination campaigns.
Objective
The objective of this scoping review was to map the current situation and available evidence and gaps on rabies morbidity, mortality, integrated rabies surveillance programmes, and existing prevention and control strategies in Africa.
Methods
We conducted a systematic scoping review following the Joanna Briggs methodology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews checklist. Medline, Embase, CINAHL (EBSCOHost), Scopus, Web of Science and rabies web conferences were used to search for peer-reviewed publications between January 1946 and May 2020. Two researchers reviewed the studies and extracted data based on author (year) and region, study design and data collection duration, participants/comparators, interventions, control conditions/exposures and outcomes (rabies mortality and morbidity) and key findings/gaps/challenges. The results were reported narratively using Arksey and O’Malley’s methodological framework.
Results
Electronic search yielded 2775 records, of which 43 studies were included. A total of 543 714 bite victims were censored through the included studies. Most of the victims were less than 15 years of age. The studies included rabies morbidity (21) and mortality (15) fluctuating in space and time across Africa depending on countries’ rabies prevention and control practices (16). Others were surveillance (nine studies); surveillance and prevention (five studies); management and control (seven studies); and surveillance, prevention and control (six studies). We found challenges in rabies reporting, existing dog vaccination programmes and post-exposure prophylaxis availability or compliance.
Conclusion
This study found challenges for dog rabies control and elimination in Africa and the need for a policy to drive the goal of zero dog-transmitted rabies to humans by 2030.
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Carnivore protoparvovirus 1 (CPPV-1) is a DNA virus causing gastrointestinal disease and immunosuppression in various terrestrial carnivores. Domestic dogs and cats are considered the primary CPPV-1 reservoirs. The habitat overlap of wild carnivores and free-roaming dogs increases the threat of CPPV-1 transmission between them. This study explored the CPPV-1 distribution among wild carnivores in Taiwan through PCR screening and compared the partial capsid protein (VP2) gene sequences from wild and domestic carnivores. In total, 181 samples were collected from 32 masked palm civets (Paguma larvata), 63 Chinese ferret badgers (Melogale moschata), and 86 crab-eating mongooses (Herpestes urva), from 2015 to 2019 were screened for CPPV-1. The average prevalence of CPPV-1 was 17.7% (32/181), with the highest prevalence in masked palm civets (37.5%). In addition, a masked palm civet was coinfected with two CPPV-1 strains. Among the 33 partial VP2 gene sequences, 23 were identical to the sequences amplified from domestic dogs and cats in Asia, and the remaining 10 were identified for the first time. This study supported the circulation of CPPV-1 strains with the same genomic features as domestic carnivores that are also in wild carnivores from the same environment in Taiwan by molecular data. Therefore, further population control and health management of free-roaming domestic carnivores are recommended.
Objective
To assess the knowledge, attitude and practices (KAP) of animal and human health professionals towards rabies management and also to establish the level of relationship between KAP.
Methods
A cross-sectional study was conducted between December 2012 and March 2013 among 147 randomly selected animal and human health professionals in Mbale District. Of these, only 16 were animal health professionals. Quantitative data was obtained using a semi-structured questionnaire while qualitative data was obtained from 4 Focus Group Discussions (FGDs) and 2 Key Informant (KI) interviews. Quantitative data was entered into EpiInfo version 3.5.1 and proportions computed while qualitative data was summarised into themes and sub-themes resulting from content analysis of interview scripts.
Findings
Of all the respondents, only 44% (65/147) had sufficient knowledge about rabies while 25% (37/147) had positive attitude towards rabies management. A half of the respondents (50%, 73/147) had limited good practices. Respondents knowledgeable about rabies were more likely to have positive attitude towards rabies management (OR = 3.65; 95% CI: 1.60–8.3) while respondents with positive attitudes, were more likely to have good practices towards rabies management (OR: 2.22; 95% CI: 1.01–4.86).
Conclusion
Respondents had low knowledge, negative attitude and limited good practices of rabies management. Regular refresher trainings about rabies to broaden staff knowledge and improve their attitudes and hence practices of rabies management should be conducted by the District leaders. Harnessing multi-sectoral and multi-disciplinary collaborative efforts (“One Health” approach) for rabies control should be instituted to reduce the incidence of the disease in the District.
Non-human primates harbor zoonotic pathogens including the ra- bies virus (Rabies lyssavirus). Though the chances of rabies trans- mission from primates is low, guidelines currently recommend a post-exposure prophylaxis for unvaccinated persons. In Madagas- car, lemurs have been described as carriers of the rabies virus, but a discussion about the risk of rabies transmission to humans from lemurs, particularly in the context of in-country ownership of lemurs, has not been studied. We use qualitative and quantitative data collected from household surveys (n = 271 interviewees who had seen a pet lemur across 12 urban towns), web-based surveys (n = 229), and the literature (publications using data collected by the Institute Pasteur of Madagascar over the last century) to ex- amine the context in which the rabies virus could be transmitted from lemurs to humans. Though only a few wild and pet lemurs in Madagascar have tested positive for rabies, post-exposure treat- ment is sometimes also sought out following aggressive incidents with lemurs. Many interviewees (22 ± 6%, mean ± 95% confidence interval CI) across 12 towns indicated that pet lemurs they had seen, had a history of aggression. Some lemur owners appear to be aware that their pets could transmit the rabies virus and seek veterinary care to prevent this. The public health burden of rabies is relatively low in Madagascar and despite some anecdotes in the literature, it appears that lemurs are rarely the source of rabies when humans become infected. However, this case study high- lights the lack of data and publications regarding the public health implications of human-lemur contact in Madagascar.
Background
The current rabies control strategy in Zambia is based on dog vaccination, dog population control and dog movement restrictions. In Nyimba district of Zambia, dog vaccination coverage is low but the incidence of dog bites is high which places the community at risk of rabies infection. The renewed global interest eliminating rabies in developing countries has spurred interest to identify determinants and barriers of dog vaccination in an effort to reduce the overall disease burden.
Methodology
A mixed methods cross sectional design was used in the study. This consisted of three parts: Evaluation of medical records regarding dog bite injuries, implementation and analysis of a household survey and in-depth review of key informant interviews. Data was collected into a Microsoft Excel database and subsequently transferred to STATA for descriptive, inferential and thematic analysis.
Results
Dog vaccination coverage overall was 8.7% (57/655), with 3.4% (22/655) in urban areas, 1.8% (12/655) in peri-urban and 3.5 (23/655) in the rural regions. Financially stable households were more likely to have their dogs vaccinated. Only 10.3% (31/300) of the respondents had vaccinated their dogs and these had a reliable source of income as 6% (18/300) were peasant farmers, 2% (6/300) were dependants whose guardians were financially stable and 2.3% (7/300) were in steady employment. Important barriers to dog vaccination included cost, limited awareness of vaccination program and access.
Conclusion
Current rabies control strategies in Nyimba district, Zambia, appear quite limited. Improvements in the regional dog vaccination program may provide benefits. Enhancement of educational efforts targeting behavioural factors may also prove useful. Finally, the cost of dog vaccination can be reduced with scaled up production of a local vaccine.
Background
Rabies is a neglected disease despite being responsible for more human deaths than any other zoonosis. A lack of adequate human and dog surveillance, resulting in low prioritization, is often blamed for this paradox. Estimation methods are often employed to describe the rabies burden when surveillance data are not available, however these figures are rarely based on country-specific data.
Methods
In 2013 a knowledge, attitudes, and practices survey was conducted in Uganda to understand dog population, rabies vaccination, and human rabies risk factors and improve in-country and regional rabies burden estimates. Poisson and multi-level logistic regression techniques were conducted to estimate the total dog population and vaccination coverage.
Results
Twenty-four villages were selected, of which 798 households completed the survey, representing 4 375 people. Dog owning households represented 12.9% of the population, for which 175 dogs were owned (25 people per dog). A history of vaccination was reported in 55.6% of owned dogs. Poverty and human population density highly correlated with dog ownership, and when accounted for in multi-level regression models, the human to dog ratio fell to 47:1 and the estimated national canine-rabies vaccination coverage fell to 36.1%. This study estimates there are 729 486 owned dogs in Uganda (95% CI: 719 919 – 739 053). Ten percent of survey respondents provided care to dogs they did not own, however unowned dog populations were not enumerated in this estimate. 89.8% of Uganda’s human population was estimated to reside in a community that can support enzootic canine rabies transmission.
Conclusions
This study is the first to comprehensively evaluate the effect of poverty on dog ownership in Africa. These results indicate that describing a dog population may not be as simple as applying a human: dog ratio, and factors such as poverty are likely to heavily influence dog ownership and vaccination coverage. These modelled estimates should be confirmed through further field studies, however, if validated, canine rabies elimination through mass vaccination may not be as difficult as previously considered in Uganda. Data derived from this study should be considered to improve models for estimating the in-country and regional rabies burden.
Electronic supplementary material
The online version of this article (doi:10.1186/s40249-017-0306-2) contains supplementary material, which is available to authorized users.
Pet dogs, therapy dogs, and service dogs can be seen in workplaces with increasing frequency. Although dogs may provide many benefits to employees and employers, their presence may introduce additional hazards and concerns to the work environment. Therefore, decisions to accept dogs in the workplace may include many considerations including the health, safety, and well-being of employees, legal and cultural sensitivities, and animal welfare. The present paper serves to introduce the issue of dogs in the workplace and outline the potential benefits and challenges to their presence. The legal accommodations afforded to certain types of dogs in workplace settings are discussed, and the research findings pertaining to the potential benefits of dogs on human health and well-being are summarized. The paper concludes with considerations for human resource management personnel in the areas of diversity, employee relations, ethics and corporate responsibility, organizational and employee development, safety and security, and legal considerations, as well as suggested topics for future research.
Control measures for canine rabies include vaccination and reducing population density through culling or sterilization.
Despite the evidence that culling fails to control canine rabies, efforts to reduce canine population density continue in many parts of the world.
The rationale for reducing population density is that rabies transmission is density-dependent, with disease incidence increasing directly with host density. This may be based, in part, on an incomplete interpretation of historical field data for wildlife, with important implications for disease control in dog populations. Here, we examine historical and more recent field data, in the context of host ecology and epidemic theory, to understand better the role of density in rabies transmission and the reasons why culling fails to control rabies.
We conclude that the relationship between host density, disease incidence and other factors is complex and may differ between species. This highlights the difficulties of interpreting field data and the constraints of extrapolations between species, particularly in terms of control policies.
We also propose that the complex interactions between dogs and people may render culling of free-roaming dogs ineffective irrespective of the relationship between host density and disease incidence.
We conclude that vaccination is the most effective means to control rabies in all species.
Background: Mass vaccinations of domestic dogs have been shown to effectively control canine rabies and hence human exposure to rabies. Knowledge of dog population demography is essential for planning effective rabies vaccination programmes; however, such information is still rare for African domestic dog populations, particularly so in urban areas. This study describes the demographic structure and population dynamics of a domestic dog population in an urban sub-Saharan African setting. In July to November 2005, we conducted a full household-level census and a cross-sectional dog demography survey in four urban wards of Iringa Municipality, Tanzania. The achievable vaccination coverage was assessed by a two-stage vaccination campaign, and the proportion of feral dogs was estimated by a mark-recapture transect study. Results: The estimated size of the domestic dog population in Iringa was six times larger than official town records assumed, however, the proportion of feral dogs was estimated to account for less than 1% of the whole population. An average of 13% of all households owned dogs which equalled a dog:human ratio of 1:14, or 0.31 dogs per household or 334 dogs km-2. Dog female:male ratio was 1:1.4. The average age of the population was 2.2 years, 52% of all individuals were less than one year old. But mortality within the first year was high (72%). Females became fertile at the age of 10 months and reportedly remained fertile up to the age of 11 years. The average number of litters whelped per fertile female per year was 0.6 with an average of 5.5 pups born per litter. The population growth was estimated at 10% y-1 .
We describe five children who died of clinical rabies in a three month period (September to November 2011) in the Queen Elizabeth Central Hospital. From previous experience and hospital records, this number of cases is higher than expected. We are concerned that difficulty in accessing post-exposure prophylaxis (PEP) rabies vaccine may be partly responsible for this rise. We advocate: (a) prompt course of active immunisation for all patients with significant exposure to proven or suspected rabid animals. (b) the use of an intradermal immunisation regime that requires a smaller quantity of the vaccine than the intramuscular regime and gives a better antibody response. (c) improved dog rabies control measures.
Rabies is a fatal neurological disease and a persistent global problem. It is spread primarily by domestic dogs but other canid, viverrid (skunks and raccoons) and chiropteran species are considered as the most efficient vectors of the disease. Since dogs are the main perpetuator of rabies, special attention has to be given to bring all the dogs including unauthorized stray dogs under immunization umbrella in order to control rabies. Vaccination is the only way to combat the disease before and after exposure or infection as there is no treatment available once the symptoms have appeared. After the first crude nerve tissue vaccine developed by Pasteur in 1885, a number of rabies vaccines for animal and human use have been developed with varying degree of safety and efficacy over the years. Presently, cell culture based inactivated rabies vaccines are largely used in most of the parts of the world. However, these vaccines are too expensive and unaffordable for vaccination of people and animals in developing countries. The comparatively cheaper inactivated nerve tissues vaccines can cause serious side-effects such as autoimmune encephalomyelitis in inoculated animals and production has been discontinued in several countries. Although attenuated live vaccines can efficiently elicit a protective immune response with a smaller amount of virus, they sometimes can cause rabies in the inoculated animals by its residual virulence or pathogenic mutation during viral propagation in the body. New-generation rabies vaccines generated by gene manipulation although in experimental stage may be a suitable alternative to overcome the disadvantages of the live attenuated vaccines. So, awareness must be created in general public about the disease and the cell culture based vaccines available in the market should be recommended for wide scale use to prevent and control this emerging and reemerging infectious disease in foreseeable future.
SUMMARY Landscape epidemiology and landscape genetics combine advances in molecular techniques, spatial analyses and epidemiological models to generate a more real-world understanding of infectious disease dynamics and provide powerful new tools for the study of RNA viruses. Using dog rabies as a model we have identified how key questions regarding viral spread and persistence can be addressed using a combination of these techniques. In contrast to wildlife rabies, investigations into the landscape epidemiology of domestic dog rabies requires more detailed assessment of the role of humans in disease spread, including the incorporation of anthropogenic landscape features, human movements and socio-cultural factors into spatial models. In particular, identifying and quantifying the influence of anthropogenic features on pathogen spread and measuring the permeability of dispersal barriers are important considerations for planning control strategies, and may differ according to cultural, social and geographical variation across countries or continents. Challenges for dog rabies research include the development of metapopulation models and transmission networks using genetic information to uncover potential source/sink dynamics and identify the main routes of viral dissemination. Information generated from a landscape genetics approach will facilitate spatially strategic control programmes that accommodate for heterogeneities in the landscape and therefore utilise resources in the most cost-effective way. This can include the efficient placement of vaccine barriers, surveillance points and adaptive management for large-scale control programmes.
Context
Rabies causes ~55 000 human deaths each year, primarily as a result of bites from dogs, which are the major rabies reservoir in the developing world. Current rabies control strategies include vaccination, culling and surgical sterilisation of dogs. However, recently developed immunocontraceptives could be used alongside vaccination to apply fertility control to more animals.
Aims
We used a modelling approach to explore (1) whether adding single-dose contraceptives to rabies vaccination would improve effectiveness of rabies eradication, (2) how sensitive control methods are to variation in population parameters and (3) the effects of applying control continuously or in pulses on rabies eradication.
Methods
A continuous time, compartmental model was created to describe canine rabies epidemiology. Parameters were derived from the literature. The following three control methods were applied at varying rates and durations: vaccination, vaccination plus fertility control (v + fc) and culling. Outcomes were classified into the following three categories: rabies persistence, rabies eradication and population extinction.
Key results
When control was applied continuously for up to 24 months, vaccination was least effective; the effort required to eradicate rabies was about twice that required with culling or v + fc. At realistic control rates, only v + fc consistently resulted in rabies eradication. Increasing population growth rate and city size made rabies eradication harder; for vaccination, considerably greater control rates and durations were required, whereas culling and v + fc showed only minor decreases in effectiveness. When control was applied for 1 or 2 months (for one month every 12 months or every 6 months) per year for up to 20 years, vaccination became less effective because of population turnover between control periods; v + fc lost little effectiveness, as decreased birth rates reduced the input of susceptible animals.
Conclusions
Using immunocontraception alongside vaccination could improve rabies control campaigns by reducing the proportion of the population that must be treated, or reducing the necessary duration of the campaign. It could also make control effective under larger population growths, in larger cities and when control is pulsed.
Implications
Immunocontraceptives could become a useful tool in canine rabies control by allowing fertility control to be applied on a large scale. Further work is required to improve understanding of dog ecology and parameterise location-specific models, which could be used to inform management plans.
Changes in the epidemiology of infectious diseases are the direct result of ecological and evolutionary changes in hosts and parasites. Precisely what the causal processes are is rarely known in any particular case, and this hinders the design of appropriate control strategies. This is particularly so for emerging infections, as opportunity is rapidly lost to study the ecological parameters which might have affected initial emergence. However, molecular evolutionary studies of the pathogens can yield data which discriminate between possible causes. The current distribution of DNA sequence variation is important information which may reveal past and current changes in pathogen population structures, and can also identify adaptive changes in pathogen genes which have affected their evolution. Such studies have been quite intensively performed on particular viral and bacterial pathogens, and some of the successes of these are noted here. Approaches to understanding the recent evolution of eukaryotic pathogens are outlined, with particular reference to current problems of emerging zoonoses, and changes in virulence and drug resistance.
The major histocompatibility complex (MHC) influences immune response to infection and vaccination. In most species, MHC genes are highly polymorphic, but few wild canid populations have been investigated. In Ethiopian wolves, we identified four DLA (dog leucocyte antigen)-DRB1, two DLA-DQA1 and five DQB1 alleles. Ethiopian wolves, the world's rarest canids with fewer than 500 animals worldwide, are further endangered and threatened by rabies. Major rabies outbreaks in the Bale Mountains of southern Ethiopia (where over half of the Ethiopian wolf population is located) have killed over 75% of wolves in the affected sub-populations. In 2004, following a rabies outbreak, 77 wolves were vaccinated, and 19 were subsequently recaptured to monitor the effectiveness of the intervention. Pre- and post-vaccination rabies antibody titres were available for 18 animals, and all of the animals sero-converted after vaccination. We compared the haplotype frequencies of this group of 18 with the post-vaccination antibody titre, and showed that one haplotype was associated with a lower response (uncorrected P < 0.03). In general, Ethiopian wolves probably have an adequate amount of MHC variation to ensure the survival of the species. However, we sampled only the largest Ethiopian wolf population in Bale, and did not take the smaller populations further north into consideration.
The inflexibility of existing serological techniques for detection of rabies in surveillance constrains the benefit to be gained from many current control strategies. We analysed 304 serum samples from Tanzanian dogs for the detection of rabies antibodies in a pseudotype assay using lentiviral vectors bearing the CVS-11 envelope glycoprotein. Compared with the widely used gold standard fluorescent antibody virus neutralisation assay, a specificity of 100% and sensitivity of 94.4% with a strong correlation of antibody titres (r=0.915) were observed with the pseudotype assay. To increase the assay's surveillance specificity in Africa we incorporated the envelope glycoprotein of local viruses, Lagos bat virus, Duvenhage virus or Mokola virus and also cloned the lacZ gene to provide a reporter element. Neutralisation assays using pseudotypes bearing these glycoproteins reveal that they provide a greater sensitivity compared to similar live virus assays and will therefore allow a more accurate determination of the distribution of these highly pathogenic infections and the threat they pose to human health. Importantly, the CVS-11 pseudotypes were highly stable during freeze-thaw cycles and storage at room temperature. These results suggest the proposed pseudotype assay is a suitable option for undertaking lyssavirus serosurveillance in areas most affected by these infections.
Effective vaccination campaigns need to reach a sufficient percentage of the population to eliminate disease and prevent future outbreaks, which for rabies is predicted to be 70%, at a cost that is economically and logistically sustainable. Domestic dog rabies has been increasing across most of sub-Saharan Africa indicating that dog vaccination programmes to date have been inadequate. We compare the effectiveness of a variety of dog vaccination strategies in terms of their cost and coverage in different community settings in rural Tanzania. Central-point (CP) vaccination was extremely effective in agro-pastoralist communities achieving a high coverage (>80%) at a low cost (<US5/dog) and inadequate (<20% coverage); combined approaches using CP and either house-to-house vaccination or trained community-based animal health workers were most effective with coverage exceeding 70%, although costs were still high (>US4/dog, respectively). No single vaccination strategy is likely to be effective in all populations and therefore alternative approaches must be deployed under different settings. CP vaccination is cost-effective and efficient for the majority of dog populations in rural Tanzania and potentially elsewhere in sub-Saharan Africa, whereas a combination strategy is necessary in remote pastoralist communities. These results suggest that rabies control is logistically feasible across most of the developing world and that the annual costs of effective vaccination campaigns in Tanzania are likely to be affordable.
Rabies remains a worldwide public health problem even though means to control this disease are known. Logistic problems and cultural barriers for effective dog control in many countries and the high cost of human postexposure treatment, account for much of the remaining worldwide human toll. Efforts to make vaccines, with effective and safe tissue or avian culture products and immune globulin, more affordable have been only marginally successful. Second generation rabies vaccines (purified Vero-, chick and duck embryo cell products) are effective, safe and less expensive than human diploid cell rabies vaccine. Reduced dose intradermal postexposure vaccination works, is affordable, and has helped abolish the use of dangerous and poorly immunogenic brain tissue-derived vaccines in Thailand, the Philippines, and Sri Lanka. The use of purified equine rabies immune globulin has been found to be safe and cost-effective. It is, unfortunately, in short supply worldwide. Preexposure rabies vaccination for travelers to endemic regions is recommended and should be administered by the intramuscular route whenever possible.
Disease in wildlife raises a number of issues that have not been widely considered in the bioethical literature. However, wildlife disease has major implications for human welfare. The majority of emerging human infectious diseases are zoonotic: this is, they occur in humans by cross-species transmissions from animal hosts. Managing these diseases often involves balancing concerns with human health against animal welfare and conservation concerns. Many infectious diseases of domestic animals are shared with wild animals, although it is often unclear whether the infection spills over from wild animals to domestic animals or vice versa. Culling is the standard means of managing such diseases, bringing economic considerations, animal welfare and conservation into conflict. Infectious diseases are also major threatening processes in conservation biology and their appropriate management by culling, vaccination or treatment raises substantial animal ethics issues. One particular issue of great significance in Australia is an ongoing research program to develop genetically modified pathogens to control vertebrate pests including rabbits, foxes and house mice. Release of any self-replicating GMO vertebrate pathogen gives rise to a whole series of ethical questions. We briefly review current Australian legal responses to these problems. Finally, we present two unresolved problems of general importance that are exemplified by wildlife disease. First, to what extent can or should 'bioethics' be broadened beyond direct concerns with human welfare to animal welfare and environmental welfare? Second, how should the irreducible uncertainty of ecological systems be accounted for in ethical decision making?
This paper reviews the broader benefits of canine vaccination to human and animal health and welfare with an emphasis on the impacts of mass dog vaccination against rabies in countries of the less-developed world. Domestic dogs are the source of infection for the vast majority (>95%) of cases of human rabies worldwide, and dogs remain the principal reservoir throughout Africa and Asia. Canine vaccination against rabies has been shown to dramatically reduce the number of cases in dogs, the incidence of human animal-bite injuries (and hence the demand for costly post-exposure prophylaxis) and the likely number of human cases, primarily in children. Further benefits include the mitigation of the psychological consequences of rabies in a community, improved attitudes towards animals and animal welfare and reduced livestock losses from canine rabies. Mass vaccination has recently been used in the conservation management of wild carnivore populations threatened by transmission of rabies and canine distemper virus from domestic dog populations. Vaccination of wildlife hosts directly may also provide an option for mitigating infectious disease threats. The development of integrated control measures involving public health, veterinary, wildlife conservation and animal welfare agencies is needed to ensure that control of canine diseases becomes a reality in Africa and Asia. The tools and delivery systems are all available--all that is needed is the political will to free the world from the ongoing tragedy of these diseases.
Rabies is a fatal neurological pathogen that is a persistent problem throughout the developing world where it is spread primarily by domestic dogs. Although the disease has been extensively studied in wildlife populations in Europe and North America, the dynamics of rabies in domestic dog populations has been almost entirely neglected. Here, we demonstrate that rabies epidemics in southern and eastern Africa cycle with a period of 3–6 years and show significant synchrony across the region. The observed period is shorter than predictions based on epidemiological parameters for rabies in domestic dogs. We find evidence that rabies prevention measures, including vaccination, are affected by disease prevalence and show that a simple model with intervention responses can capture observed disease periodicity and host dynamics. We suggest that movement of infectious or latent animals combined with coordinated control responses may be important in coupling populations and generating synchrony at the continental scale. These findings have important implications for rabies prediction and control: large-scale synchrony and the importance of intervention responses suggest that control of canine rabies in Africa will require sustained efforts coordinated across political boundaries.
• disease dynamics
• epidemics
• infectious disease
• mathematical model
• vaccination
Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection. Development of appropriate interventions requires detailed data on transmission pathways between reservoirs and wildlife populations of conservation concern. Relevant data can be derived from long-term population monitoring, epidemic and case-surveillance patterns, genetic analyses of rapidly evolving pathogens, serological surveys, and intervention studies. We examined studies of carnivore diseases in the Serengeti. Epidemiological research contributes to wildlife conservation policy in terms of management of endangered populations and the integration of wildlife conservation with public health interventions. Long-term, integrative, cross-species research is essential for formulation of effective policy for disease control and optimization of ecosystem health.
With an apparent decline in rabies vaccination coverage in dog populations in many parts of eastern and southern Africa, consideration should be given to more effective targeting of rabies vaccination to protect those sectors of the dog population with the greatest capacity to transmit rabies. This paper discusses the potential contributions that dog ecology studies may make to the improved delivery of rabies control measures and the targeting of vaccination programmes in the region. Data requirements on dog population size and structure are discussed, methods for collection of such data are summarized, and the studies on dog ecology carried out to date within the region are reviewed.
Results from a one year longitudinal study of dog ecology on 150 dog-owning households in Machakos District, Kenya are presented. The sample of study dogs had a high turnover rate with half of the dogs replaced over the year. Overall life expectancy was estimated at 2.8 to 2.9 years. Males had a live expectancy of 3.5 years and females 2.4 years. Only 39 percent of female dogs survived to one year of age. High mortality was balanced by high fecundity (1.3 females produced per female per year) so that the population was estimated to grow by 9 percent (± 5 percent). Two distinct density (dog/km 2) patterns were observed, one peri-urban area with a dog density of 110/km 2 and five rural areas in which dog densities average 2 approximately 10/km 2 . Based on these results we conclude that annual rabies vaccination is insufficient and that rabies vaccines which can be given at 3 months of age are required. Further information needs for the appropriate design of vaccination programmes for rural dog populations are discussed.
A random sample survey using personal interviews was conducted in Zimbabwe in 1986 to determine the size and structure of the national dog population and its level of rabies vaccination. There was an average of 0.91 dogs per household in Zimbabwe giving an extrapolated total population of 1,308,577 dogs. There was a dog to people ratio of 1:6.5 and an average of 3.4 dogs per square kilometre. The ratio of adult male to female dogs was 0.56:0.44, with 20 per cent of the dog population being less than three months old. In the period 1950 to 1986 there was a 4.7 per cent per annum growth rate of the dog population. In one of the provinces, Manicaland, dogs were found to have an average age of 2.3 years and a life expectancy at birth of 4.6 years. An estimated 40 per cent of the dog population three months old and above had been vaccinated against rabies in 1985/1986. With the rabies incidence in Zimbabwe still unacceptably high this level of vaccination is clearly inadequate and measures designed to increase it are discussed.
Analysis of the present situation in canine-rabies-infected countries shows that in most cases the levels of activities for controlling the disease in man and in dogs are far too low to prevent human deaths due to rabies and to eliminate the disease in the dog population. This article compares the two major orientations of a rabies control programme, i.e., prevention of the disease in man by intensifying and modernizing post-exposure treatment (strategy A) and canine rabies elimination by controlling the disease in the animal reservoir (strategy B). The operation of both strategies (A + B) together is also analysed. Based on the available data and assumptions for calculations of the costs, the results show that when the strategies are applied independently of each other, the annual cost of strategy B amounts to 25-56% of that of strategy A. When the two strategies are applied together, the actual annual spending related to the implementation of A + B becomes less than that of strategy A alone as from the fifth year following programme initiation. The sensitivity of the results was tested against selected fluctuations in the assumptions. An estimation of the costs of control activities per avoided death, according to the strategy applied, is also given. In countries where resources allocated to rabies control are inadequate in both the health and veterinary sectors, the comparison in costs and effectiveness of the two programme strategies for rabies elimination strongly suggests that consideration should be given to a national programme of dog rabies elimination. On the other hand, for obvious ethical reasons, if attention is paid to improvement of post-exposure treatment, then the national authorities should consider a planning horizon close to 15 years.
Dog rabies control relies principally on the mass immunization of dogs in order to achieve population immunity levels sufficient to inhibit rabies transmission. In Africa, such high levels of population immunity are rarely achieved due to a number of reasons. Oral immunization has been shown to be an effective means of inducing high levels of immunity in fox populations in several European countries, and this technique has been mooted as a means of overcoming the logistical problems of delivering injectable rabies vaccines to dogs. This paper discusses the requirements for oral rabies vaccines for dogs in Africa and reviews the trials performed to date on baits and baiting systems suitable for the delivery of such vaccines. Issues affecting possible rabies vaccine distribution in the future are discussed and the major research issues still to be tackled are summarized.
Characteristics of dog populations and their accessibility for rabies vaccination were compared in an urban and a semi-rural area in Zambia. A total of 1,190 households were interviewed. In the urban study area (Mutendere, a low income suburb of Lusaka) only 11% of the households kept dogs with a dog:human ratio of 1:45. In the semi-rural area (Palabana) dogs were kept by 42% of households with a dog:human ratio of 1:6,7. In conjuction with the study of the dog populations in these two areas, immunization of dogs against rabies was provided by door-to-door visits in both study areas and also through central point vaccination in the urban area. The attitude of the public towards free rabies vaccinations was positive, although some misconceptions regarding indications and modalities of treatment following exposure to suspect dogs were found. Approximately 50% of the dog removals were as a result of disease and the demand for dogs was higher than the supply. Although only information on the owned segment of the dog population was obtained during the study, the proportion of ownerless dogs appeared to be very low. Generally, there is a need for better co-ordination between the different services involved in rabies control in Zambia to enhance the sustainability of vaccination programmes and improve the treatment of persons bitten by dogs.
Lycaon pictus is amongst the most endangered wildlife species in Africa. In 1990 rabies virus was isolated from the brain of an adult Lycaon found dead in the Serengeti region of Tanzania. One adult and six pups of the same pack feeding on the carcass showed clinical signs and rabies was suspected; within two days they had disappeared and are presumed to have died. Subsequently, two Lycaon packs in the Serengeti National Park were given inactivated rabies vaccine either by dart or by parenteral inoculation following anaesthesia. Lycaon sera which had been collected over the previous two years and sera collected pre- and post-vaccination were examined for the presence of rabies virus neutralizing antibody. Three of 12 unvaccinated Lycaon had antibody levels > 0.5 IU/ml; post-vaccination samples from two Lycaon showed increased antibody levels. Between four and ten months post-vaccination, at least four of the vaccinated animals had died from unknown causes. Issues relating to wildlife vaccination and veterinary intervention in conservation are discussed.
Rabies in bat-eared foxes was first recognized in South Africa in 1955 and is likely to have been derived from canine rabies introduced to South Africa in 1950. Since then it has become established in this species in the drier western half of the country and the south-western Cape so that rabies now occurs in bat-eared foxes adjacent to the peri-urban canine population of Cape Town. Peak incidence was recorded in the early 1980s and the incidence is seasonal with most cases occurring in winter.
The black-backed jackal is represented in rabies records from southern Africa and is suspected of playing an important role in the disease in this region. The basic biology of the species suggests that it does have certain characteristics that could make it an ideal rabies vector. However, the engimatically low incidence of rabies in undisturbed jackal populations suggests that more subtle processes may be involved. It is suggested that jackal society is arranged in the form of cryptic packs and that disruption of the hierachy through persecution may increase agonistic encounters and thence the incidence of rabies. Suggestions are made for the incorporation of the jackal in rabies control programmes without resorting to extermination.
The first confirmed outbreak of rabies in Africa, believed to have followed the importation of an infected dog from England in 1892, occurred in the eastern Cape Province of South Africa, and was brought under control in 1894. An unconfirmed epidemic of rabies in dogs occurred in western Zambia in 1901. By the following year the disease had apparently spread along a major trade route, to cause an outbreak in Zimbabwe which engulfed most of the country before being eradicated in 1913. The existence of endemic rabies of viverrids (mongooses and genets) was confirmed in South Africa in 1928, and since then the viverrid disease has continued to occur widely on the interior plateau of the country with spill-over of infection to cattle and a variety of other animals. From about 1947 onwards, an invasive form of dog rabies spread from southern Zambia and/or Angola into Namibia, across northern and eastern Botswana into Zimbabwe and the northern Transvaal by 1950, entered Mozambique in 1952, and spread from there to Swaziland in 1954. Dog rabies extended from southern Mozambique into Natal in 1961 to cause a major epidemic which was brought under control in 1968. The disease re-entered northern Natal from Mozambique in 1976 and since then dog rabies has proved difficult to control in the peri-urban settlements of Natal-KwaZulu. The disease spread from Natal to Lesotho in 1982, and into the Transkei region of the eastern Cape Province in 1987, to reach the Ciskei by 1990. The spread of the disease in dogs was followed by the emergence of rabies of jackals and cattle in central Namibia, northern Botswana, Zimbabwe and the northern Transvaal. A unique outbreak of rabies in kudu antelope occurred in central Namibia from 1977 to 1985, apparently involving oral spread of infection between individuals. A few cases of rabies in the bat-eared fox were recognized each year in Namibia from 1967 onwards, and from the 1970s the occurrence of the disease in the fox has emerged as a distinct problem in the northern Cape Province and spread to the west coast. The rabies-related viruses, Lagos bat, Mokola and Duvenhage, associated with bats, shrews and rodents in Africa, are known to have caused isolated cases of disease in South Africa, and on one occasion a small outbreak involving six cats and a dog in Bulawayo, Zimbabwe.(ABSTRACT TRUNCATED AT 400 WORDS)
Whether and how microparasites such as rabies persist in their host populations are among the fundamental questions of infectious disease epidemiology. Rabies is fatal disease of all mammalian species, but not all mammalian species can maintain the infection as reservoirs. The approach to control depends on which of the affected species do act as reservoirs. Bringing together old and new data, we examine here the role of wild and domestic animals in maintaining rabies in the Serengeti region of Tanzania, presenting our findings in two parts. In Part I, we argue that domestic dogs are the likely reservoirs because: (1) rabies has been continuously present in the dog population since its (re)introduction in 1977, whilst (2) wildlife cases have been very rare over this period, despite intensive study of Serengeti carnivores; (3) outbreaks of rabies in wild canids (jackals) elsewhere in Africa (Zimbabwe) have followed, rather than preceded, outbreaks in the dog population; (4) all viruses isolated from wild carnivores in the Serengeti ecosystem (including the Kenyan Masai Mara) are antigenically and genetically indistinguishable from the typical domestic dog strain; (5) dog rabies control in the Serengeti between 1958-77 apparently eliminated the disease from both dogs and wildlife. Having identified dogs as reservoirs, Part II explores some possible mechanisms of maintenance in dog populations. In theory, infection is more likely to be maintained at higher dog densities, and we provide evidence that rabies is maintained in one district with a dog density > 5/km2, but not in two other districts with densities < 1/km2. Because 5 dogs/km2 is much lower than the expected density required for persistence, we go on to investigate the role of atypical infections, showing: (1) from serology, that a substantial proportion of healthy dogs in the Serengeti have detectable serum levels of rabies-specific antibody; (2) from mathematical models that, whilst we cannot be sure what seropositivity means, persistence in low-density dog populations is more likely if seropositives are infectious carriers, rather than slow-incubators or immunes.
WHO recommends that 70% of dogs in a population should be immunized to eliminate or prevent outbreaks of rabies. This critical percentage (pc) has been established empirically from observations on the relationship between vaccination coverage and rabies incidence in dog populations around the world. Here, by contrast, we estimate pc by using epidemic theory, together with data available from four outbreaks in urban and rural areas of the USA, Mexico, Malaysia and Indonesia. From the rate of increase of cases at the beginning of these epidemics, we obtain estimates of the basic case reproduction number of infection, R0, in the range 1.62-2.33, implying that pc lies between 39% and 57%. The errors attached to these estimates of pc suggest that the recommended coverage of 70% would prevent a major outbreak of rabies on no fewer than 96.5% of occasions.