Mycobacterium bovis is the cause of tuberculosis (TB) in a wide range of species, including white rhinoceroses (Ceratotherium simum). Control of the disease relies on the indirect detection of infection by measuring pathogen-specific responses of the host. These are poorly described in the white rhinoceros and this study aimed to characterize the kinetics of immune responses to M. bovis infection in this species. Three white rhinoceroses were infected with M. bovis and their immune sensitization to this pathogen was measured monthly for 20 months. Cell-mediated immunity was characterized in whole blood samples as the differential release of interferon-gamma in response to bovine purified protein derivative (PPDb) and avian PPD (PPDa) as well as the release of this cytokine in response to the M. bovis proteins 6 kDa early secretory antigenic target (ESAT-6)/10 kDa culture filtrate protein (CFP-10). Humoral immunity was quantified as the occurrence or the magnitude of antibody responses to the proteins ESAT-6/CFP-10, MPB83, MPB83/MPB70, and PPDb. The magnitude and duration of immune reactivity varied between individuals; however, peak responses to these antigens were detected in all animals circa 5–9 months postinfection. Hereafter, they gradually declined to low or undetectable levels. This pattern was associated with limited TB-like pathology at postmortem examination and appeared to reflect the control of M. bovis infection following the development of the adaptive immune response. Measurement of these markers could prove useful for assessing the disease status or treatment of naturally infected animals. Moreover, immune responses identified in this study might be used to detect infection; however, further studies are required to confirm their diagnostic utility.
Ostrich (Struthio camelus) chicks less than 3 mo age are observed to experience a high mortality rate that is often associated with enteritis. This study was undertaken to investigate the infectious bacteria implicated in ostrich chick enteritis. Postmortems were performed on 122 ostrich chicks aged from 1 d to 3 mo and intestinal samples were subjected to bacterial culture. Bacterial isolates were typed by PCR and serotyping. Escherichia coli (E. coli; 49%) was the most frequently isolated from the samples followed by Clostridium perfringens (C. perfringens; 20%), Enterococcus spp. (16%), and Salmonella spp. (7%). Of the E. coli, 39% were categorized as enteropathogenic E. coli, 4% enterotoxigenic E. coli, and no enterohaemorrhagic E. coli were found. The majority (93%) of C. perfringens was Type A and only 7% was Type E. C. perfringens Types B through D were not present. The netB gene that encodes NetB toxin was identified from 16% of the C. perfringens isolated. All the C. perfringens Type E harbored the netB gene and just 10% of the C. perfringens Type A had this gene. Three Salmonella serotypes were identified: Salmonella Muenchen (S. Muenchen; 80%), S. Hayindongo (13%), and S. Othmarschen (7%). The indication is that the cause of enteritis in ostrich chicks is bacterial-involving: enteropathogenic E. coli and enterotoxigenic E. coli; C. perfringens Types A and E (with the possible influence of netB gene); and S. Muenchen, S. Hayindongo, and S. Othmarschen.
Rickettsia africae is a bacterium of zoonotic importance, which causes African tick bite fever (ATBF) in humans. This pathogen is transmitted by ticks of the genus Amblyomma, with Amblyomma hebraeum and Amblyomma variegatum being the major vectors. Tick species other than the above-mentioned have also been reported to carry R. africae DNA. There is scarcity of information on the epidemiology of this pathogen, yet several cases have been recorded in foreign travellers who visited endemic areas, especially southern Africa. The disease has rarely been described in people from endemic regions. The aim of this study was to discuss the information that is currently available on the epidemiology of R. africae, highlighting the gaps in this field. Furthermore, ATBF cases, clinical signs and the locations where the cases occurred are also listed in this review.
Toxoplasma gondii (T. gondii) is a protozoan parasite, which infects a wide variety of mammals and bird species globally. In large parts of the world, this parasite is relatively well documented in wildlife species, however, this topic is poorly documented in Africa. The current review systematically explores the presence and distribution of T. gondii in African wildlife species through a key word search in PubMed, Web of Science and CAB Direct. A total of 66 records were identified and included in the qualitative analysis, of which 19 records were retained for the quantitative synthesis. The presence of T. gondii was reported in a wide range of wildlife species, found in twelve countries, spread over the African continent. The retained records report a prevalence range of 6–100% in herbivores, 8–100% in omnivores and 14–100% in carnivores. In wild felines (cheetahs, leopards, and lions) a prevalence range of 33–100% was found. Reports from South Africa, and on the presence of T. gondii in lion were most common. Overall, the results indicate the scarcity of information on T. gondii in Africa and its circulation in wildlife. The lack of knowledge on the parasite in Africa, especially in areas at the human-livestock-wildlife interface, prevents us from understanding how prevalent it is on the continent, what strains are circulating in wildlife and what the most common routes of transmission are in the different habitats in Africa.
Tuberculosis (TB) is a global health concern of zoonotic importance, and Mycobacterium bovis and Mycobacterium tuberculosis are the most common causes of TB in animals and humans, respectively. Integral to TB control strategies are the communities affected by this epidemic. Tuberculosis awareness by the community is an effective TB control strategy as education empowers people to make informed choices with regard to mitigating TB risk factors in their daily lives. We conducted a knowledge, attitude and perceptions survey in Mnisi pastoral community in South Africa using a semi-structured questionnaire to evaluate the level of bovine TB (bTB) awareness, and provided informed feedback to the community on the outcome of the study. Although participants were aware of TB, the knowledge of the zoonotic potential of bTB and about susceptible hosts was limited. The study findings showed knowledge gaps regarding common risk factors, including coughing while herding cattle, unsupervised/uninspected communal slaughter and improper disposal of infected meat. In contrast, it was noted that the majority of participants discarded meat with visible lesions and consumed pasteurised milk; thus, the risk of TB transmission via the ingestion route is low. Tuberculosis knowledge gaps were evident in the community, and public health and veterinary authorities need to improve relationships with stakeholders and implement awareness programmes that use a one health approach.
A joint international program in Tropical Animal Health was launched in 2016 by the Institute of Tropical Medicine, Antwerp, Belgium, and the Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria. This program is flexible in time, place, and curriculum, allowing part-time students to apply the program’s learning outcomes directly in their daily work environment. This article focuses on the major challenges and issues related to developing an international joint program in general and how these challenges were addressed. Challenges such as incompatibility of admission procedures, merging academic calendars, and quality assurance mechanisms were mitigated partly by the type of collaboration and partly by using a joint e-learning platform. The e-learning format proved to be a solution for particular challenges such as mobility issues, joint development of course material, and administrative processes. Furthermore, we present the results of a survey on the experiences of graduates and facilitators in this unique joint, web-based program.
The study determined the prevalence, risk factors, and characteristics of Campylobacter species contamination of chicken carcasses sold at informal poultry outlets in Gauteng, South Africa. Using six townships, 151 chicken carcasses were collected from 47 outlets. Carcass and cloacal swabs, as well as carcass drip, were collected from each chicken along with a matched questionnaire on risk factors regarding Campylobacter contamination. Sample-inoculated Bolton broth (BB) was cultured to isolate Campylobacter species by bacteriological methods. Then confirmation and characterization of Campylobacter were conducted using polymerase chain reaction (PCR). Campylobacter strains isolated in this study were evaluated for the presence of six virulence genes (ciaB, dnaj, pldA, racR, flaA, flaB ), three toxin genes (cdtA, cdtB, cdtC) and one antimicrobial resistance gene (tetO). The overall prevalence of Campylobacter was 23.4% (106/453) with sample type-specific prevalence being 17.2% (26/151), 25.8% (39/151), and 27.2% (41/151) for the carcass, cloacal swabs, and carcass drips, respectively. The overall prevalence of Campylobacter species was 93.5% by PCR, which varied significantly (P=0.000) by sample, 99.2%, 98.4%, and 82.8% for carcass swabs, cloacal swabs, and carcass drips, respectively . Important risk factors for carcass contamination by Campylobacter included the slaughter of culled breeders, spent chickens, poor sanitation, and the use of stagnant water. Virulence and toxin genes frequencies were higher in C. jejuni (81.5%) than in C. coli (71.4%) positive BB cultures, but tetracycline resistance gene (tetO) frequency was higher in C. coli (75.9%) than in C. jejuni (48.10%). The observed high frequencies in C. jejuni recovered from street-vended chickens may pose food safety and therapeutic concerns to consumers.
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