[Show abstract][Hide abstract] ABSTRACT: Hypothermia contributes to neonatal morbidity and mortality in low-income countries, yet little is known about thermal care practices in rural African settings. We assessed adoption and community acceptability of recommended thermal care practices in rural Tanzania.
BMC Pregnancy and Childbirth 08/2014; 14(1):267. · 2.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Controlled human malaria infection (CHMI) by mosquito bite has been used to assess new anti-malaria interventions in > 1,500 volunteers since development of methods for infecting mosquitoes by feeding on Plasmodium falciparum (Pf) gametocyte cultures. Such CHMIs have never been used in Africa. Aseptic, purified, cryopreserved Pf sporozoites, PfSPZ Challenge, were used to infect Dutch volunteers by intradermal injection. We conducted a double-blind, placebo-controlled trial to assess safety and infectivity of PfSPZ Challenge in adult male Tanzanians. Volunteers were injected intradermally with 10,000 (N = 12) or 25,000 (N = 12) PfSPZ or normal saline (N = 6). PfSPZ Challenge was well tolerated and safe. Eleven of 12 and 10 of 11 subjects, who received 10,000 and 25,000 PfSPZ, developed parasitemia. In 10,000 versus 25,000 PfSPZ groups geometric mean days from injection to Pf positivity by thick blood film was 15.4 versus 13.5 (P = 0.023). Alpha-thalassemia heterozygosity had no apparent effect on infectivity. PfSPZ Challenge was safe, well tolerated, and infectious.
The American journal of tropical medicine and hygiene 07/2014; · 2.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In Sub-Saharan Africa over one million newborns die annually. We developed a sustainable and scalable home-based counselling intervention for delivery by community volunteers in rural southern Tanzania to improve newborn care practices and survival. Here we report the effect on newborn care practices one year after full implementation.
[Show abstract][Hide abstract] ABSTRACT: Sleeping under a net, particularly a long-lasting insecticidal net (LLIN), is associated with reduced malaria morbidity and mortality, but requires high coverage and adherence. In this study, parasitologically confirmed Plasmodium falciparum infection and a clinical indicator (i.e. fever) were measured among children in three villages of central Cote d'Ivoire (Bozi, N'Dakonankro and Yoho) and associations with net coverage explored. In Bozi and Yoho, LLINs were provided by the national malaria control programme, prior to the study and an additional catch-up coverage was carried out in Bozi. In N'Dakonankro, no net intervention was conducted.
[Show abstract][Hide abstract] ABSTRACT: Community-based service delivery is vital to the effectiveness, affordability and sustainability of vector control generally, and to labour-intensive larval source management (LSM) programmes in particular.Case description: The institutional evolution of a city-level, community-based LSM programme over 14 years in urban Dar es Salaam, Tanzania, illustrates how operational research projects can contribute to public health governance and to the establishment of sustainable service delivery programmes. Implementation, management and governance of this LSM programme is framed within a nested set of spatially-defined relationships between mosquitoes, residents, government and research institutions that build upward from neighbourhood to city and national scales.Discussion and evaluation: The clear hierarchical structure associated with vertical, centralized management of decentralized, community-based service delivery, as well as increasingly clear differentiation of partner roles and responsibilities across several spatial scales, contributed to the evolution and subsequent growth of the programme.
[Show abstract][Hide abstract] ABSTRACT: Non-communicable diseases dominate the public health arena in China, yet neglected tropical diseases (NTDs) are still widespread and create a substantial burden. We review the geographical distribution, prevalence, and epidemic characteristics of NTDs identified in China caused by helminths, protozoa, bacteria, and viruses. Lymphatic filariasis was eliminated in 2007, but schistosomiasis still affects up to 5% of local village residents in some endemic counties with around 300 000 people infected. China harbours more than 90% of the world's burden of alveolar echinococcosis and food-borne zoonoses are emerging. In 2010, the overall prevalence of soil-transmitted helminth infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworm was 11·4%, with 6·8% of these infections caused by A lumbricoides. Corresponding figures for food-borne trematodiasis, echinococcosis, and cysticercosis are more than 5%. Dengue, leishmaniasis, leprosy, rabies, and trachoma exist in many areas and should not be overlooked. Transmission of vector-borne diseases can be interrupted; nevertheless, epidemics occur in remote areas, creating a challenge for surveillance and control. Rigorous surveillance, followed by immediate and integrated response packages tailored to specific social and ecological systems, is essential for progress towards the elimination of NTDs in China.
The Lancet Infectious Diseases 05/2014; · 19.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The use of long-lasting insecticidal nets (LLINs) is an effective malaria control strategy. However, there are challenges to achieve high coverage, such as distribution sustainability, and coverage keep-up. This study assessed the effect of LLINs coverage and contextual factors on entomological indicators of malaria in rural Cote d'Ivoire.
The study was carried out between July 2009 and May 2012 in three villages (Bozi, N'Dakonankro and Yoho) of central Cote d'Ivoire. In Bozi and Yoho, LLINs were distributed free of charge by the national malaria control programme in 2008. In Bozi, an additional distribution was carried out in May 2011. No specific interventions were done in N'Dakonankro. Entomological surveys were conducted in July 2009 and July 2010 (baseline), and in August and November 2011 and in February 2012. Frequency of circumsporozoite protein was determined using an enzyme-linked immunosorbent assay. Regression models were employed to assess the impact of LLINs and changing patterns of irrigated rice farming on entomological parameters, and to determine associations with LLINs coverage and other contextual factors.
In Bozi, high proportion of LLIN usage was observed (95-100%). After six months, 95% of LLINs were washed at least once and 79% were washed up to three times within one year. Anopheles gambiae was the predominant malaria vector (66.6% of all mosquitoes caught). From 2009 to 2012, in N'Dakonankro, the mean annual entomological inoculation rate (EIR) increased significantly from 116.8 infectious bites/human/year (ib/h/y) to 408.8 ib/h/y, while in the intervention villages, the EIR decreased significantly from 514.6 ib/h/y to 62.0 ib/h/y (Bozi) and from 83.9 ib/h/y to 25.5 ib/h/y (Yoho). The risk of an infectious bite over the three-year period was significantly lower in the intervention villages compared to the control village (p <0.001).
High coverage and sensitization of households to use LLINs through regular visits (particularly in Bozi) and abandoning irrigated rice farming (in Yoho) resulted in highly significant reductions of EIR. The national malaria control programme should consider household sensitization and education campaigns and other contextual factors to maximize the benefit of LLINs.
[Show abstract][Hide abstract] ABSTRACT: Objective
Aiming at a simple, inexpensive and robust tool for HIV-1 drug resistance genotyping during antiretroviral therapy (ART) we developed and validated a microarray-based detection of 25 drug resistance mutations most relevant for the Tanzanian ART regimen.MethodsA reverse transcriptase gene fragment was reverse-transcribed and amplified by reverse transcription–polymerase chain reaction (RT–PCR). Primers for mini-sequencing were designed based on alignments of the most prevalent local HIV-1 variants. Tagged primers were extended by fluorochrome-labelled dideoxynuclotide triphosphate (ddNTPs) to indicate the single-nucleotide polymorphism (SNP) allele of the sample tested, followed by hybridisation on treated microarray slides. Images were analysed with a laser scanner and genotype calling was performed using in-house developed software.ResultsThe microarray was validated with four cloned HIV-1 genome fragments from a Swiss HIV-1 cohort and 102 HIV-1 sequences amplified from the Tanzanian target population (field samples). Results were concordant with the Sanger sequencing SNP profile in 92.7% of 2550 SNP data points compared. Lack of signals in small number of SNPs was due to either failure in the extension reaction or hybridisation owing to mismatches between PCR product and extension primer.Conclusion
Our study demonstrates the feasibility of hybridisation-based genotyping of drug resistance mutations of HIV, even though our microarray, which was designed for population studies, achieved only correct assignment of 92% of all SNPs in the tested samples.
Tropical Medicine & International Health 03/2014; · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Since 2010, World Health Organization (WHO) guidelines discourage using stavudine in first-line regimens due to frequent and severe side effects. This study describes the implementation of this recommendation and trends in usage of antiretroviral therapy combinations in a cohort of HIV-positive patients in rural Tanzania.
We analyzed longitudinal, prospectively collected clinical data of HIV-1 infected adults initiating antiretroviral therapy within the Kilombero Ulanga Antiretroviral Cohort (KIULARCO) in Ifakara, Tanzania from 2007-2011.
This analysis included data of 3008 patients. Median age was 38 (interquartile range [IQR] 31-45) years, 1962 (65.2%) of all subjects were female, and median CD4+ cell count at enrollment was 168 cells/mm3 (IQR 81-273). The percentage of prescriptions containing stavudine in initial regimens fell from a maximum of 75.3% in 2008 to 10.7% in 2011. TDF/FTC/EFV became available in 2009 and was used in 41.9% of patients initiating cART in 2011. An overall on-treatment analysis revealed that d4T/3TC/NVP and AZT/3TC/EFV were the most prescribed combinations in each year, including 2011 (674 [36.5%] and 641 [34.7%] patients, respectively). Of those receiving stavudine in 2011, 659 (89.1%) initiated it before 2011.
Initial cART with stavudine declined to low levels according to recommendations but the overall use of stavudine remained substantial, as individuals already on cART containing stavudine were not changed to alternative drugs. Our findings highlight the critical need to exchange stavudine in treatment regimens of patients who initiated therapy in earlier years.
[Show abstract][Hide abstract] ABSTRACT: Tropical diseases remain a major cause of morbidity and mortality in developing countries. Although combined health efforts brought about significant improvements over the past 20 years, communities in resource-constrained settings lack the means of strengthening their environment in directions that would provide less favourable conditions for pathogens. Still, the impact of infectious diseases is declining worldwide along with progress made regarding responses to basic health problems and improving health services delivery to the most vulnerable populations. The London Declaration on Neglected Tropical Diseases (NTDs), initiated by the World Health Organization's NTD roadmap, set out the path towards control and eventual elimination of several tropical diseases by 2020, providing an impetus for local and regional disease elimination programmes. Tropical diseases are often patchy and erratic, and there are differing priorities in resources-limited and endemic countries at various levels of their public health systems. In order to identify and prioritize strategic research on elimination of tropical diseases, the 'First Forum on Surveillance-Response System Leading to Tropical Diseases Elimination' was convened in Shanghai in June 2012. Current strategies and the NTD roadmap were reviewed, followed by discussions on how to identify and critically examine prevailing challenges and opportunities, including inter-sectoral collaboration and approaches for elimination of several infectious, tropical diseases. A priority research agenda within a 'One Health-One World' frame of global health was developed, including (i) the establishment of a platform for resource-sharing and effective surveillance-response systems for Asia Pacific and Africa with an initial focus on elimination of lymphatic filariasis, malaria and schistosomiasis; (ii) development of new strategies, tools and approaches, such as improved diagnostics and antimalarial therapies; (iii) rigorous validation of surveillance-response systems; and (iv) designing pilot studies to transfer Chinese experiences of successful surveillance-response systems to endemic countries with limited resources.
[Show abstract][Hide abstract] ABSTRACT: Background: This study aimed to synthesize available evidence on the efficacy of dihydroartemisinin-piperaquine (DHP) in treating uncomplicated Plasmodium vivax malaria in people living in endemic countries.
[Show abstract][Hide abstract] ABSTRACT: The genetic diversity of Plasmodium falciparum allows the molecular discrimination of otherwise microscopically identical parasites and the identification of individual clones in multiple infections. The study reported here investigated the P. falciparum multiplicity of infection (MOI) and genetic diversity among school-aged children in the Man region, western Cote d'Ivoire.
Blood samples from 292 children aged seven to 15 years were collected in four nearby villages located at altitudes ranging from 340 to 883 m above sea level. Giemsa-stained thick and thin blood films were prepared and examined under a microscope for P. falciparum prevalence and parasitaemia. MOI and genetic diversity of the parasite populations were investigated using msp2 typing by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).
Plasmodium falciparum prevalence and parasitaemia were both found to be significantly lower in the highest altitude village. Genotyping of the isolates revealed 25 potentially new msp2 alleles. MOI varied significantly across villages but did not correlate with altitude nor children's age, and only to a limited extent with parasitaemia. An analysis of molecular variance (AMOVA) indicated that a small, but close to statistical significance (p = 0.07), fraction of variance occurs specifically between villages of low and high altitudes.
Higher altitude was associated with lower prevalence of P. falciparum but not with reduced MOI, suggesting that, in this setting, MOI is not a good proxy for transmission. The evidence for partially parted parasite populations suggests the existence of local geographical barriers that should be taken into account when deploying anti-malarial interventions.
[Show abstract][Hide abstract] ABSTRACT: This study aimed to synthesize available evidence on the extent of malaria and soil-transmitted intestinal helminth (STH) co-infections in people living in endemic countries and to explore the effect of interactions between malaria and STHs on anemia. We searched relevant studies in electronic databases up to March 2013. Studies comparing malaria and STH co-infected patients with those not co-infected were included and the effect estimates were pooled using a random-effects model. We identified 30 studies for meta-analyses of which 17 were cross-sectional design. The majority of included studies (80%) were carried out in African countries. Among pregnant women, those infected with hookworm were found to have higher association with malaria infection compared with those without (summary OR: 1.36; 95% CI: 1.17-1.59; I(2): 0%). Among non-pregnant adults, the summary OR of the association between anemia and the combined malaria and STH was 2.91 (1.38-6.14). The summary OR of the association between anemia and malaria alone was 1.53 (0.97-2.42), while the association between anemia and STH alone was 0.28 (0.04-1.95). There is no good evidence to support a different effect of malaria and STH on anemia. A subgroup analysis showed a higher risk of malaria infection in the primigravidae (summary OR: 1.61; 95% CI: 1.3-1.99; I(2): 0%). In conclusion, the malaria-STH co-infection was variable with complex outcomes on anemia.
Transactions of the Royal Society of Tropical Medicine and Hygiene 11/2013; 107(11):672-683. · 1.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Access to sufficient quantities of safe drinking water is a human right. Moreover, access to clean water is of public health relevance, particularly in semi-arid and Sahelian cities due to the risks of water contamination and transmission of water-borne diseases. We conducted a study in Nouakchott, the capital of Mauritania, to deepen the understanding of diarrhoeal incidence in space and time. We used an integrated geographical approach, combining socio-environmental, microbiological and epidemiological data from various sources, including spatially explicit surveys, laboratory analysis of water samples and reported diarrhoeal episodes. A geospatial technique was applied to determine the environmental and microbiological risk factors that govern diarrhoeal transmission. Statistical and cartographic analyses revealed concentration of unimproved sources of drinking water in the most densely populated areas of the city, coupled with a daily water allocation below the recommended standard of 20 l per person. Bacteriological analysis indicated that 93% of the non-piped water sources supplied at water points were contaminated with 10-80 coliform bacteria per 100 ml. Diarrhoea was the second most important disease reported at health centres, accounting for 12.8% of health care service consultations on average. Diarrhoeal episodes were concentrated in municipalities with the largest number of contaminated water sources. Environmental factors (e.g. lack of improved water sources) and bacteriological aspects (e.g. water contamination with coliform bacteria) are the main drivers explaining the spatio-temporal distribution of diarrhoea. We conclude that integrating environmental, microbiological and epidemiological variables with statistical regression models facilitates risk profiling of diarrhoeal diseases. Modes of water supply and water contamination were the main drivers of diarrhoea in this semi-arid urban context of Nouakchott, and hence require a strategy to improve water quality at the various levels of the supply chain.
Geospatial health 11/2013; 8(1):53-63. · 1.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Progress towards reaching Millennium Development Goals four (child health) and five (maternal health) is lagging behind, particularly in sub-Saharan Africa, despite increasing efforts to scale up high impact interventions. Increasing the proportion of birth attended by a skilled attendant is a main indicator of progress, but not much is known about the quality of childbirth care delivered by these skilled attendants. With a view to reducing maternal mortality through health systems improvement we describe the care routinely offered in childbirth offered at dispensaries, health centres and hospitals in five districts in rural Southern Tanzania. We use data from a health facility census assessing 159 facilities in five districts in early 2009. A structural and operational assessment was undertaken based on staff reports using a modular questionnaire assessing staffing, work load, equipment and supplies as well as interventions routinely implemented during childbirth.
Health centres and dispensaries attended a median of eight and four deliveries every month respectively. Dispensaries had a median of 2.5 (IQR 2--3) health workers including auxiliary staff instead of the recommended four clinical officer and certified nurses. Only 28% of first-line facilities (dispensaries and health centres) reported offering active management in the third stage of labour (AMTSL). Essential childbirth care comprising eight interventions including AMTSL, infection prevention, partograph use including foetal monitoring and newborn care including early breastfeeding, thermal care at birth and prevention of ophthalmia neonatorum was offered by 5% of dispensaries, 38% of health centres and 50% of hospitals consistently. No first-line facility had provided all signal functions for emergency obstetric complications in the previous six months.
Essential interventions for childbirth care are not routinely implemented in first-line facilities or hospitals. Dispensaries have both low staffing and low caseload which constraints the ability to provide high-quality childbirth care. Improvements in quality of care are essential so that women delivering in facility receive "skilled attendance" and adequate care for common obstetric complications such as post-partum haemorrhage.
[Show abstract][Hide abstract] ABSTRACT: Dans le Sahel, entre la Mauritanie et la Somalie incluant le Nord Kenya, environ 20 à 30 millions de personnes vivent en transhumance. Le rythme de leur migration suit l'évolution saisonnière du climat et la disponibilité des ressources, telle que l'eau, le pâturage et le sel. Malgré une exposition élevée à certaines maladies comme les zoonoses et les problèmes conditionnés liés au climat, les pasteurs mobiles sont parmi les populations quasiment exclues du système de santé, car la mise à disposition des services sociaux adaptés à un mode de vie mobile est difficile. Suivant l'objectif de recherche d'un meilleur accès aux soins des pasteurs mobiles, l'Institut Tropical et de Santé Publique Suisse, en partenariat avec plusieurs institutions dans la région, est actif au Sahel depuis 15 ans, aussi bien dans le domaine de la recherche, que celui des actions de développement. Basées sur une approche orientée vers les besoins des pasteurs mobiles pour leur développement, des recherches interdisciplinaires ont contribué à mieux comprendre la situation et les problèmes des éleveurs. En relation de la proximité entre l'homme et son bétail, une approche unissant la santé humaine et animale s'est avérée bonne et la valeur ajoutée d'une meilleure collaboration entre médecine humaine, animale et l'environnement a été démontrée. Ces approches utiles devraient être poursuivies et consolidées dans les recherches et le développement des actions futurs.
Tropical Medicine & International Health 07/2013; · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the Sahel, between Mauritania and Somalia including Northern Kenya, about 20-30 million people live as mobile pastoralists. The rhythm of their migration follows the seasons and the availability of resources such as water, pasture and salt. Despite their high exposure to zoonoses and problems caused by extreme climatic conditions, mobile pastoralists are virtually excluded from health services because the provision of social services adapted to their way of life is challenging. In cooperation with various partners in the region, the Swiss Tropical and Public Health Institute has been active in research and development in the Sahel for 15 years. Based on the perceived needs of mobile pastoralists and the necessities of development, interdisciplinary research has considerably contributed to better understanding of their situation and their problems. Close contact between humans and livestock necessitates close cooperation between human and animal health specialists. Such useful approaches should be continued and extended.
Tropical Medicine & International Health 07/2013; · 2.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: ABSTRACT The development of resistance mutations in drug-targeted HIV-1 genes compromises the success of antiretroviral therapy (ART) programmes. Genotyping of these mutations enables adjusted therapeutic decisions both at the individual and population level. We investigated over time the prevalence of HIV-1 primary drug resistance mutations in treatment naive patients and described the HIV-1 subtype distribution in a cohort in rural Tanzania at the beginning of the ART rollout in 2005-2007 and later in 2009. Viral RNA was analyzed in 387 baseline plasma samples from treatment naïve patients over a period of five years. The reverse transcriptase (RT) and protease genes were reversely transcribed, PCR amplified, and directly sequenced to identify HIV-1 subtypes and single nucleotide polymorphisms associated with drug resistance (DR-SNPs). The prevalence of major DR-SNPs in 2005-2007 in the RT gene was determined: K103N (5.0%), Y181C (2.5%), M184V (2.5%), G190A (1.7%) and M41L, K65KR, K70KR and L74LV (0.8%). In samples from 2009 only K103N (3.3%), M184V and T215FY (0.8%) were detected. Initial frequencies of subtypes C, A, D and recombinants were 43%, 32%, 18% and 7%, respectively. Later similar frequencies were found except for the recombinants which were found twice as much (15%), highlighting the subtype diversity and a relatively stable subtype frequency in the area. DR-SNPs were found at initiation of the cohort despite very low previous ART use in the area. Statistically frequencies of major mutations did not change significantly over the studied five-year interval. These mutations could reflect primary resistances and may indicate a possible risk for treatment failure.
AIDS research and human retroviruses 06/2013; · 2.18 Impact Factor