[Show abstract][Hide abstract] ABSTRACT: Reasons for performing study:
Equine grass sickness (EGS) is of unknown aetiology. Despite some evidence suggesting that it represents a toxico-infection with Clostridium botulinum types C and/or D, the effect of EGS on the functional targets of botulinum neurotoxins (BoNTs), namely the soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins, is unknown. Further, while it is commonly stated that, unlike EGS, equine botulism is not associated with autonomic and enteric neurodegeneration, this has not been definitively assessed.
To determine (a) whether botulism causes autonomic and enteric neurodegeneration, and (b) the effect of EGS on the expression of SNARE proteins within cranial cervical ganglion [CCG] and enteric neuronal perikarya.
Light microscopy was used to compare the morphology of neurons in haematoxylin-eosin stained sections of CCG and ileum from 6 EGS horses, 5 botulism horses and 6 control horses. Immunohistochemistry was used to compare the expression of synaptosomal-associated protein-25 (SNAP-25), synaptobrevin (Syb) and syntaxin (Syn) within CCG neurons, and of Syb in enteric neurons, from horses with EGS, horses with botulism and control horses. The concentrations of these SNARE proteins in extracts of CCG from EGS and control horses were compared using quantitative fluorescent western blotting (QFWB).
EGS, but not botulism, was associated with autonomic and enteric neurodegeneration and with increased immunoreactivity for SNARE proteins within neuronal perikarya. QFWB confirmed increased concentrations of SNAP-25, Syb and Syn within CCG extracts from EGS versus control horses, with the increases in the latter two proteins being statistically significant.
Conclusions and potential relevance:
The occurrence of autonomic and enteric neurodegeneration, and increased expression of SNARE proteins within neuronal perikarya, in EGS but not botulism, suggests that EGS may not be caused by BoNTs. Further investigation of the aetiology of EGS is therefore warranted. This article is protected by copyright. All rights reserved.
No preview · Article · Dec 2015 · Equine Veterinary Journal
[Show abstract][Hide abstract] ABSTRACT: Beak and feather disease is caused by Circovirus, which affects actively growing beak and feather cells of avian species. The disease affects mainly young birds while older birds may overcome the disease with few lasting effects. Due to lack of treatment, the only way to control the disease is through hygiene and early diagnosis. As a diagnostic tool, we have established a Taqman probe based real-time PCR assay to detect the presence of the viral genome in psittacine birds in UAE and reported the incidence of circovirus in different species of psittacine birds. The sensitivity of our assay was found to be very high with detection limit of up to 3.5fg of DNA in the sample. The mean prevalence of circovirus was found to be 58.33% in African Grey Parrots, 34.42% in Cockatoos, 31.8% in amazon parrots and 25.53% in Macaws.
[Show abstract][Hide abstract] ABSTRACT: Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 have continued to perpetuate with divergent genetic variants in poultry within Asia since 2003. Further dissemination of Asian origin-derived H5 HPAI viruses to Europe, Africa and, most recently, to the North American continent, have occurred. We report an outbreak of HPAI H5N1 virus among falcons kept for hunting and other wild bird species bred as falcon prey from Dubai, United Arab Emirates, during fall 2014. The causative agent was identified as avian influenza virus H5N1 subtype, clade 220.127.116.11c, by genetic and phylogenetic analyses. High mortality in infected birds was in accordance with systemic pathomorphological and histological alterations in affected falcons. Genetics analysis showed the HPAI H5N1 of clade 18.104.22.168c is a reassortant in which the PB2 segment was derived from an Asian origin H9N2 virus lineage. The Dubai H5N1 viruses were closely related to contemporary H5N1 HPAI viruses from Nigeria, Burkina-Faso, Romania and Bulgaria. Median-joining network analysis of 22.214.171.124c viruses revealed that the Dubai outbreak was an episode of a westward spread of these viruses on a larger scale from unidentified Asian sources. The incursion into Dubai, possibly via infected captive hunting falcons returning from hunting trips to central Asian countries, preceded outbreaks in Nigeria and other Western African countries. The alarmingly enhanced geographic mobility of clade 126.96.36.199.c and clade 188.8.131.52 viruses may represent another wave of transcontinental dissemination of Asian origin HPAIV H5 viruses, such as the outbreak at Qinghai lake caused by the clade 2.2 ("Qinghai" lineage) in 2005.
No preview · Article · Sep 2015 · Journal of General Virology
[Show abstract][Hide abstract] ABSTRACT: Although camelids are an important domestic species with more than 25 million members, little is known about vaccine adjuvant efficacy, safety and mechanism of action in this species. This presents a major problem for design of effective camelid vaccines. This is of more than theoretical interest given the recent emergence of. camels as vectors of transmission to humans of lethal viral diseases such as Middle Eastern Respiratory Syndrome (MERS) coronavirus. Hence availability of well-validated camelid vaccine adjuvants may be important not just for vaccines to prevent diseases of Camels but also to block their ability to transmit disease to humans. In this study, we used dromedaries to. test the safety and efficacy of four different adjuvant formulations (Advax (TM) HCXL, Advax AF-1, Advax AF-2 or alum) together with four different antigen formulations (B. mallei, C. pseudotuberculosis, C. perfringens, Rhinovirus) administered by subcutaneous injection in the neck region of adult animals. All the Advax delta inulin-based adjuvants and the alum adjuvant were well tolerated, with no severe lesions such as the draining granulomas that are caused by oil emulsion adjuvants. There was no trend for increased vaccine reactogenicity in camels that had existing immunity to the vaccine antigens. Overall, the vaccines had modest immunogenicity in these adult animals indicating the need for further research to identify the optimal adjuvant formulation, dose and immunisation route for camelid vaccines.
Full-text · Article · Jun 2015 · Journal of Camel Practice and Research
[Show abstract][Hide abstract] ABSTRACT: The teat canals and mammary gland cisterns of 30 necropsied omniparous non-lactating dromedaries aged between 8 and 20 years were microbiologically investigated. In total 242 teat canals and 242 cisterns were swabbed from which 36 different bacterial species comprising 17 families were isolated. In total 24% teat canals and 22% mammary cisterns harboured bacteria colonies but they grew only in very low numbers of between 1 to 13 colonies per agar plate. It can be stated that our investigation revealed that a high number of dromedary glands are either sterile or harbour only a low number of mainly non-mastitis pathogens.
No preview · Article · Jun 2015 · Journal of Camel Practice and Research
[Show abstract][Hide abstract] ABSTRACT: Camel brucellosis has been diagnosed in all camel-rearing countries except Australia. In many countries the infection is on the rise in Old World camels (OWCs) due to the uncontrolled trade of live animals. Knowledge of camelid brucellosis has increased over the last decade through field investigations, experimental infection trials and comprehensive laboratory testing. Infection with Brucella melitensis is frequent in OWCs and rare with B. abortus. New World Camels rarely contract brucellosis. In East African countries the seroprevalence of brucellosis can reach 40% (herd level) and depends on the management system. The highest incidence is found when camels are kept together with infected small ruminants. Only a combination of serological methods can detect all serological reactors. Culturing the pathogen is still the preferred test method, although several assays based on polymerase chain reaction have been developed.
No preview · Article · Dec 2014 · Revue scientifique et technique (International Office of Epizootics)
[Show abstract][Hide abstract] ABSTRACT: Haemotrophic mycoplasmosis or haemoplasmosis, caused by the haemotrophic mycoplasma species Candidatus Mycoplasma haemolamae (formerly Haemobartonella), has been described in both Old World camels (OWCs) and New World camels (NWCs) from different countries. Camelid anaplasmosis (formerly Ehrlichiosis) caused by Anaplasma marginale has been described in OWCs only. Knowledge of these pathogens in camels in the United Arab Emirates (UAE) is missing. We investigated 55 clinically healthy, but slightly anaemic dromedaries in the UAE for the occurrence of haemotrophic mycoplasmas and Anaplasma marginale using blood smear investigations and polymerase chain reaction (PCR). In the blood smears, neither of the two pathogens was detectable and the investigations using PCR methods did not reveal any DNA from Cand. M. haemolamae or A. marginale in 55 slightly anaemic UAE dromedaries. So far, the cause of anaemia in those dromedaries remains to be further analysed.
No preview · Article · Jun 2014 · Journal of Camel Practice and Research
[Show abstract][Hide abstract] ABSTRACT: The Middle East Respiratory Syndrome (MERS) caused by a coronavirus emerged in the Middle East in 2012, and has killed so far more than 300 people most of them in Saudi Arabia. MERS is a zoonotic disease and transmission from the dromedary camel to humans has been documented. However, most cases occur between humans. The low incidence of transmission from camel to human has several reasons. The virus is excreted only for 8 days and mainly young dromedaries are infected which have very little or no contact to their caretakers. It has yet not been proven how and from where the calves get there infection. Over 90% of adult dromedaries possess specific MERS-CoV antibodies and do not shed the virus. Thirty dromedaries (15 dams and 15 calves) were tested at the Saudi Arabian border to the UAE for MERS-CoV infection. All dams had seroconverted, but were PCR and virus negative. However, 13 of their offsprings had antibodies to MERS-CoV, 11 (73%) were positive in PCR and from 5 (33%) MERS-CoV was isolated. A visit 8 days later showed that all had seroconverted, 4 (27%) remained PCR positive but none exhibited virus in their nasal cavities.
No preview · Article · Jun 2014 · Journal of Camel Practice and Research
[Show abstract][Hide abstract] ABSTRACT: We tested, using a low starting dilution, sequential serum samples from dromedary camels, sheep and horses collected in Dubai from February/April to October of 2005 and from dromedary camels for export/import testing between Canada and USA in 2000-2001. Using a standard Middle East respiratory syndrome coronavirus (MERS-CoV) neutralization test, serial sera from three sheep and three horses were all negative while sera from 9 of 11 dromedary camels from Dubai were positive for antibodies supported by similar results in a MERS-CoV recombinant partial spike protein antibody ELISA. The two negative Dubai camels were both dromedary calves and remained negative over the 5 months studied. The six dromedary samples from USA and Canada were negative in both tests. These results support the recent findings that infection with MERS-CoV or a closely related virus is not a new occurrence in camels in the Middle East. Therefore, interactions of MERS-CoV at the human-animal interface may have been ongoing for several, perhaps many, years and by inference, a widespread pandemic may be less likely unless significant evolution of the virus allow accelerated infection and spread potential in the human population.
Full-text · Article · Jan 2014 · Transboundary and Emerging Diseases