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Genetic diversity of <i>Ehrlichia ruminantium</i> strains in Cameroon
2014
Seraphine N. Esemu | Roland N. Ndip | Lucy M. Ndip
In order to investigate the extent of genetic diversity among Ehrlichia ruminantium strains in Cameroon, a partial fragment (800 bp) of the E. ruminantium map1 gene was amplified by nested polymerase chain reaction in 121 of 156 E. ruminantium pCS20-positive DNA samples extracted from ticks and cattle collected from two ranches. Deoxyribonucleic acid sequencing of the map1 gene products indicated the presence of at least 21 genotypes at the nucleotide level and 16 genotypes at the amino acid level circulating within the study sites. Some of the genotypes were identical to Antigua (U50830), Blaaukrans (AF368000) or UmBanein (U50835), whilst the others were new genotypes. Twenty-four representative sequences were deposited in GenBank and given accession numbers JX477663 – JX477674 (for sequences of tick origin) and JX486788 – JX486799 (for sequences of cattle origin). Knowledge of E. ruminantium strain diversity could be important in understanding the epidemiology of heartwater
Show more [+] Less [-]Validation of an ELISA for the concurrent detection of total antibodies (IgM and IgG) to Rift Valley fever virus
2014
Charlotte E. Ellis | Vuyokazi E. Mareledwane | Roy Williams | David B. Wallace | Phelix A.O. Majiwa
Rift Valley fever virus (RVFV) infects humans and livestock, causing haemorrhaging andabortions in animals. Three major RVF epizootics have occurred in South Africa since the1950s and the outbreak in 2010 had a mortality rate of 10.7% in humans. Accurate and earlydetection is therefore essential for management of this zoonotic disease. Enzyme-linkedimmunosorbent assays (ELISAs) have been developed for the detection of either IgM or IgGantibodies to RVFV in animal sera. In this study, data are presented on the validation of adouble-antigen ELISA for the simultaneous detection of both classes of antibodies to RVFV ina single test. ELISA plates were coated with a recombinant nucleoprotein. The nucleoprotein,conjugated to horseradish peroxidase, was used as the detecting reagent. A total of 534 serafrom sheep and cattle were used in the validation. The sheep sera were collected during a RVFpathogenesis study at the Agricultural Research Council (ARC) – Onderstepoort VeterinaryInstitute and the cattle sera were collected during an outbreak of RVF in 2008 at the ARC –Animal Production Institute in Irene, Pretoria. The ELISA had a diagnostic sensitivity of 98.4%and a specificity of 100% when compared to a commercial cELISA. This convenient and fastassay is suitable for use in serological surveys or monitoring immune responses in vaccinatedanimals.
Show more [+] Less [-]The risk factors for human cysticercosis in Mbulu District, Tanzania
2014
Beda J. Mwang'onde | Gamba Nkwengulila | Mwita Chacha
The objective of this study was to explore the reasons for the persistence of human cysticercosis (HCC) transmission in Mbulu District, northern Tanzania. The study was carried out in 25 villages, whereby five major risks were identified. The risks were indiscriminate defaecation and improper use of toilets; a free-range system of keeping pigs; indiscriminate or unregulated slaughtering and inadequate meat hygiene and inspection; consumption of undercooked and porcine cysticerci infected pork; and social structure and roles. All of the identified risks were backed up by the immanent lifestyles of the community involved. These findings are important for the development of intervention strategies in the study area.
Show more [+] Less [-]Two genotypes of infectious bronchitis virus are responsible for serological variation in KwaZulu-Natal poultry flocks prior to 2012
2014
Adrian D. Knoetze | Niloshni Moodley | Celia Abolnik
This study describes the isolation, serotyping and genotyping of 54 infectious bronchitis virus (IBV) cases predominantly in KwaZulu-Natal and compared to several isolates from other South African provinces between 2011 and 2012 and several historic isolates. The results indicate the division of isolates into two different genotypes of IBV within the province, Massachusetts (Mass)-like and QX-like. The IBV Mass-like genotype was the most prevalent and was detected in 79% of the full spike protein S1 gene sequences. Variation up to 22.3% was detected within local Mass-type strains, supporting the hypothesis that multiple IBV serotypes may co-circulate in the same region simultaneously. Additionally, more conservation was observed amongst Mass serotypes versus QX-like serotypes, implying that vaccine use can influence the variability within the IBV population; this is deduced from the fact that the only live vaccine registered for use in South Africa at the time of the study was of Mass origin and no QX-like vaccines were available for use. This study offers the first published consolidation of IBV isolates from an area of South Africa and identifies variation within the IBV population of the broiler flock within the study area over a 2-year period.
Show more [+] Less [-]Serosurveillance of foot-and-mouth disease virus in selected livestock-wildlife interface areas of Tanzania
2014
Mathias Mkama | Christopher J. Kasanga | Raphael Sallu | Ezekia Ranga | Mmeta Yongolo | Misheck Mulumba | Mark Rweyemamu | Philemon Wambura
Foot-and-mouth disease (FMD) is caused by a virus of the genus Aphthorvirus of the family Picornaviridae. There is great scientific need for determining the transmission dynamics of FMD virus (FMDV) by drawing more attention to the livestock-wildlife interface areas. A variety of literature suggests that buffalo could serve as reservoir of FMDV in wildlife and cattle. However, many FMDV research studies conducted on experimentally infected cattle as carriers and groups of animal highly susceptible to FMDV (i.e. bovine calves) have shown lower chances of transmission of the virus between carriers and the susceptible groups. These findings underscore the importance of continued research on the role played by carrier animals on FMDV transmission dynamics under natural conditions. The aim of this research study was to determine FMDV infection status among buffalo and cattle herds in selected livestock-wildlife interface areas. The sampled areas included Mikumi, Mkomazi and Ruaha national parks, where a total of 330 buffalo and bovine sera samples were collected. Laboratory analysis of the samples was done through the NSP ELISA technique using the PrioCHECK® FMDV NS Kit for detection of antibodies directed against 3ABC non-structural proteins and confirming natural infections. Results showed that 76.3% of tested sera samples were positive for FMDV. However, serotyping of NSP ELISA seroreactors with LPBE is yet to be done. This information is important for further epidemiological studies towards developing effective FMD control strategies.
Show more [+] Less [-]The changing landscape for health research in Africa: The focus of the Southern African Centre for Infectious Diseases and Surveillance
2014
Mark M. Rweyemamu | Esron D. Karimuribo | Leonard E.G. Mboera
Detection of misfolded prion protein in retina samples of sheep and cattle by use of a commercially available enzyme immunoassay
2014
Smith, Jodi D. | Greenlee, Justin J.
Objective-To determine the usefulness of retina samples for detection of disease-associated prion protein by use of a commercially available enzyme immunoassay (EIA) intended for rapid identification of sheep and cattle with transmissible spongiform encephalopathies (TSEs). Samples-Retina, brainstem at the level of the obex, and retropharyngeal lymph node samples obtained from 15 TSE-inoculated sheep (scrapie [n = 13] or transmissible mink encephalopathy passaged through a bovid [2]); retina and brainstem samples obtained from 11 TSE-inoculated cattle (transmissible mink encephalopathy passaged through a bovid [7] or classical BSE [4]); and negative control tissue samples obtained from 2 sheep and 2 cattle that were not inoculated with TSEs. Procedures-Tissue samples were homogenized and analyzed for detection of abnormally folded disease-associated prion protein with a commercially available EIA and 2 confirmatory assays (western blot analysis or immunohistochemical analysis). Results-Retina sample EIA results were in agreement with results of brainstem sample EIA or confirmatory assay results for negative control animals and TSE-inoculated animals with clinical signs of disease. However, TSE-inoculated animals with positive confirmatory assay results that did not have clinical signs of disease had negative retina sample EIA results. Retina sample EIA results were in agreement with brainstem sample immunohistochemical results for 4 TSE-inoculated sheep with negative retropharyngeal lymph node EIA results. Conclusions and Clinical Relevance-Results of this study suggested that retina samples may be useful for rapid EIA screening of animals with neurologic signs to detect TSEs.
Show more [+] Less [-]Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens
2014
Pei, Y. | Parreira, V.R. | Roland, K.L. | Curtiss, R. III. | Prescott, J.F.
Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors.
Show more [+] Less [-]Relevance of synovial fluid chondroitin sulphate as a biomarker to monitor polo pony joints
2014
Baccarin, R.Y. | Rasera, L. | Machado, T.S. | Michelacci, Y.M.
Osteoarthritis (OA) of the metacarpophalangeal joint is the most common articular disease in polo ponies leading to early retirement. A biomarker that would discriminate between pathological and physiological changes secondary to exercise could be helpful in OA prevention. The aim of this study was to investigate the effects of polo training on synovial fluid biomarkers of inflammation and cartilage turnover in polo ponies of different skill levels. Synovial fluid samples were collected from metacarpophalangeal joints of polo ponies before and during the polo season (320 d). Nucleated cells, soluble protein, prostaglandin E2 (PGE2), glycosaminoglycans (GAG), and urea were measured. The main synovial fluid GAG are chondroitin sulphate (CS, ~25 μg/mL) and hyaluronic acid (HA, ~400 μg/mL). After a polo match, a transitory increase in protein and PGE2, but not CS and HA, occurred (expressed as urea ratio), returning to basal levels in 24 h. During the polo season, the number of synovial fluid nucleated cells was always in the normal range. Increases in protein and HA occurred during the initial 40 to 80 d, returning to basal levels afterwards. In contrast, in polo prospects the concentration of CS steadily increased during the season. Long-term follow-up revealed that the synovial fluid CS was significantly higher in polo ponies that developed joint diseases within 24 months following our study. In conclusion, CS seems to be an early marker of articular cartilage damage.
Show more [+] Less [-]Specific contrast ultrasound using sterically stabilized microbubbles for early diagnosis of thromboembolic disease in a rabbit model
2014
Vlasín, Michal | Lukác, Robert | Kauerová, Zuzana | Kohout, Pavel | Mašek, Josef | Bartheldyová, Eliska | Koudelka, Stepán | Korvasová, Zina | Plocková, Jana | Hronová, Nikola | Turánek, Jaroslav
Specific contrast ultrasound is widely applied in diagnostic procedures on humans but remains underused in veterinary medicine. The objective of this study was to evaluate the use of microbubble-based contrast for rapid ultrasonographic diagnosis of thrombosis in small animals, using male New Zealand white rabbits (average weight about 3.5 kg) as a model. It was hypothesized that the use of microbubble-based contrast agents will result in a faster and more precise diagnosis in our model of thrombosis. A pro-coagulant environment had been previously established by combining endothelial denudation and external vessel wall damage. Visualization of thrombi was achieved by application of contrast microbubbles [sterically stabilized, phospholipid-based microbubbles filled with sulfur hexafluoride (SF6) gas] and ultrasonography. As a result, rapid and clear diagnosis of thrombi in aorta abdominalis was achieved within 10 to 30 s (mean: 17.3 s) by applying microbubbles as an ultrasound contrast medium. In the control group, diagnosis was not possible or took 90 to 180 s. Therefore, sterically stabilized microbubbles were found to be a suitable contrast agent for the rapid diagnosis of thrombi in an experimental model in rabbits. This contrast agent could be of practical importance in small animal practice for rapid diagnosis of thrombosis.
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