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Species identification and cow risks of non-aureus staphylococci from South African dairy herds
2022
Inge-Marie Petzer | Christiaan Labuschagne | Lufuno Phophi | Joanne Karzis
Detailed information on specific species of non-aureus staphylococci (NAS) has become a necessity for effective udder health control programs in South Africa. The main objective of this preliminary study was to identify the different NAS species and strains present in dairy herds in South Africa using a cost-effective method. A further objective was to investigate the effects of cow risk factors and farming systems on the NAS isolates identified. A total of 214 NAS, isolated from milk collected from 17 South African dairy herds, were identified using three diagnostic tests (API Staph test, MALDI-TOF and 16s rRNA). There was a good observed agreement between the MALDI-TOF and 16S rRNA sequencing (92.2%) and a poor observed agreement between the MALDI-TOF and API Staph (25.7%). The genetic relatedness within species was investigated in 128 of these isolates using random polymorphic amplified deoxyribonucleic acid (DNA) (RAPD), verified by multilocus sequence typing (MLST), and phylogenetic analysis and cow risk factors were investigated on species level. The main NAS species isolated were Staphylococcus chromogenes (75.2%), Staphylococcus epidermidis (9.4%) and Staphylococcus haemolyticus (8.9%). The RAPD test identified 34 Staphylococcus chromogenes, 13 Staphylococcus epidermidis and nine Staphylococcus haemolyticus strains, indicating genetic diversity amongst strains and herds. The presence of NAS intramammary infections was found to be significantly related to the farming systems, composite cow milk somatic cell count (SCC), parity and days in milk (DIM). Significantly more NAS were isolated from primiparous and from older cows. This knowledge could assist with the management of NAS on dairy farms.
Mostrar más [+] Menos [-]Orf in South Africa: Endemic but neglected
2012
Alessandra Scagliarini | Silvia Piovesana | Filippo Turrini | Federica Savini | Fortune Sithole | Cheryl M. McCrindle
A survey amongst sheep and goat producers and veterinarians was undertaken to collect epidemiological data on orf in South Africa. Previous epidemiological studies on the presence of the disease in the country have not been documented and this report is the first descriptive epidemiological study of orf in South Africa. A seven-month investigation, realised by direct and indirect interviews and field observation, enabled us to outline incidence and risk factors of this disease and to better understand how the local farmers in rural areas relate to it. The results may contribute to better management of the disease in rural areas. By means of molecular analyses the phylogenetic relationships between field isolates from different areas have been identified. The findings gave a first important contribution to the general assessment of the economic impact of orf virus infections and the extent of the risk to human health.
Mostrar más [+] Menos [-]The diagnosis and prevalence of persistent infection with bovine viral diarrhoea virus in South African feedlot cattle
2011
Thelma Meiring | Leon Prozesky | Eben R. du Preez | Dirk J. Verwoerd
Bovine viral diarrhoea virus (BVDV) infection is an important viral infection affecting the cattle industry today. The prevalence of this infection in South African feedlots is unknown. Ear notch biopsies were collected from chronic poor doers and animals that appeared unthrifty upon entering feedlots, as well as animals entering the hospital pen with respiratory disease for the first time. A total of 1690 samples were collected: 1074 from the former category and 616 from the latter. A routine immunohistochemistry staining protocol showed that 49 animals tested positive, of which 43 (4%) came from the feedlot entry group and six (1%) from the hospitalised group. The prevalence of persistently infected cattle from this selected, nonrandom sample entering six large South African feedlots was found to be 2.9%, which is higher than the international rule of thumb that 0.5% of all cattle entering feedlots are persistently infected. There was no clear correlation between persistent infection and respiratory disease. Serum samples were also collected when possible and 10 positive cases were found. Results from enzyme-linked immunosorbent assays for antigen and antibody performed on these sera correlated well with those from the immunohistochemistry staining method in six cases, but in four cases the animals tested falsely positive owing to nonspecific staining. Immunohistochemistry staining on ear notch biopsies is thus a reliable diagnostic method to identify persistently infected animals with BVDV, but the pathologist should be aware of nonspecific positive staining.
Mostrar más [+] Menos [-]Updated distribution and host records for the argasid tick Ornithodoros (Pavlovskyella) zumpti: A potential vector of African swine fever virus in South Africa
2021
Anthony F. Craig | Livio Heath | Jan E. Crafford | Juergen A. Richt | Robert Swanepoel
African swine fever virus (ASFV) causes a lethal and contagious disease of domestic pigs. In South Africa, the virus historically circulated in warthogs and ornithodorid ticks that were only found in warthog burrows in the north of the country. Regulations implemented in 1935 to prevent transfer of infected animals or products to the south initially proved effective but from 2016 there have been outbreaks of disease in the south that cannot be traced to transfer of infection from the north. From 1963 there were widespread translocations of warthogs to the south, initially from a source considered to be free of ornithodorid ticks. We undertook to determine whether sylvatic circulation of ASFV occurs in the south, including identification of potential new vectors, through testing extralimital warthogs for antibody and ticks for virus. Results of testing warthogs for antibody and other species of ticks for virus will be presented separately. Here we report finding Ornithodoros (Pavlovskyella) zumpti ticks in warthog burrows for the first time. This occurred in the Eastern Cape Province (ECP) in 2019. Since African swine fever was recognised in the ECP for the first time in 2020 and outbreaks of the disease in domestic pigs continue to occur there, priority should be given to determining the distribution range and vector potential of O. (P.) zumpti for ASFV.
Mostrar más [+] Menos [-]Antigenic characterisation of lyssaviruses in South Africa
2014
Ernest Ngoepe | Christine Fehlner-Gardiner | Alex Wandeler | Claude Sabeta
There are at least six Lyssavirus species that have been isolated in Africa, which include classical rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus and Ikoma lyssavirus. In this retrospective study, an analysis of the antigenic reactivity patterns of lyssaviruses in South Africa against a panel of 15 anti-nucleoprotein monoclonal antibodies was undertaken. A total of 624 brain specimens, collected between 2005 and 2009, confirmed as containing lyssavirus antigen by direct fluorescent antibody test, were subjected to antigenic differentiation. The lyssaviruses were differentiated into two species, namely rabies virus (99.5%) and Mokola virus (0.5%). Furthermore, rabies virus was further delineated into two common rabies biotypes in South Africa: canid and mongoose. Initially, it was found that the canid rabies biotype had two reactivity patterns; differential staining was observed with just one monoclonal antibody. This difference was likely to have been an artefact related to sample quality, as passage in cell culture restored staining. Mongoose rabies viruses were more heterogeneous, with seven antigenic reactivity patterns detected. Although Mokola viruses were identified in this study, prevalence and reservoir host species are yet to be established. These data demonstrate the usefulness of monoclonal antibody typing panels in lyssavirus surveillance with reference to emergence of new species or spread of rabies biotypes to new geographic zones.
Mostrar más [+] Menos [-]Rumen protozoa in South African sheep with a summary of the worldwide distribution of sheep protozoa
2011
Dirk Booyse | Burk A. Dehority
Protozoa species were identified in rumen contents of four domestic sheep (Ovis aries) from South Africa. All animals were fed a forage diet which consisted of 50% lucerne and 50% teff hay. Ten new host records were identified, bringing the total number of species and forms observed in sheep in South Africa to 30. The occurrence and geographic distribution of ciliate protozoa in both domestic and wild sheep from around the world are summarised. It was found that 15 genera and 131 species occur in domestic sheep globally.
Mostrar más [+] Menos [-]Clinical Coxiella burnetii infection in sable and roan antelope in South Africa
2024
Wikus Wiedeman | Akorfa B. Glover | Johan Steyl | Jacques O'Dell | Henriette van Heerden
Various zoonotic microorganisms cause reproductive problems such as abortions and stillbirths, leading to economic losses on farms, particularly within livestock. In South Africa, bovine brucellosis is endemic in cattle, and from 2013–2018, outbreaks of Brucella melitensis occurred in sable. Coxiella burnetii, the agent responsible for the zoonotic disease known as Q-fever and/or coxiellosis, also causes reproductive problems and infects multiple domestic animal species worldwide, including humans. However, little is known of this disease in wildlife. With the expansion of the wildlife industry in South Africa, diseases like brucellosis and coxiellosis can significantly impact herd breeding success because of challenges in identifying, managing and treating diseases in wildlife populations. This study investigated samples obtained from aborted sable and roan antelope, initially suspected to be brucellosis, from game farms in South Africa using serology tests and ruminant VetMAX™ polymerase chain reaction (PCR) abortion kit. The presence of C. burnetii was confirmed with PCR in a sable abortion case, while samples from both sable and roan were seropositive for C. burnetii indirect enzyme-linked immunosorbent assay (iELISA). This study represents the initial report of C. burnetii infection in sable and roan antelope in South Africa. Epidemiological investigations are crucial to assess the risk of C. burnetii in sable and roan populations, as well as wildlife and livestock in general, across South Africa. This is important in intensive farming practices, particularly as Q-fever, being a zoonotic disease, poses a particular threat to the health of veterinarians and farm workers as well as domestic animals. Contribution: A report of clinical C. burnetii infection in the wildlife industry contributes towards the limited knowledge of this zoonotic disease in South Africa.
Mostrar más [+] Menos [-]An investigation into Toxoplasma gondii at the human-livestock-wildlife interface, South Africa
2024
Refilwe P. Bokaba | Veronique Dermauw | Darshana Morar-Leather | Pierre Dorny | Louis van Schalkwyk | Luis Neves
Interface areas shared by humans, domestic and wild animals may serve as high transmission contexts for Toxoplasma gondii. However, knowledge about the epidemiology of T. gondii in such areas is currently limited. The present study assessed the seroprevalence of T. gondii in different hosts from Mpumalanga, South Africa. Furthermore, we investigated the local knowledge and related practices about T. gondii by conducting a questionnaire study in the community. Blood samples were obtained and analysed for T. gondii antibodies using a commercial multispecies latex agglutination kit. The seroprevalence detected in humans (n = 160; patients showing signs of acute febrile illness), cats (n = 9), chickens (n = 336) and goats (n = 358) was 8.8%, 0.0%, 4.2% and 11.2%, respectively. Seroprevalence in impalas (n = 97), kudus (n = 55), wild dogs (n = 54), wildebeests (n = 43), warthogs (n = 97) and zebras (n = 68) was calculated at 5.2%, 7.3%, 100.0%, 20.9%, 13.4% and 9.1%, respectively. The questionnaire revealed that 63.0% of household owners were subsistence farmers, and 35.9% were pet owners. A high level of female participation was found (75.3%) when compared to male participation (24.7%). The results show a low circulation of T. gondii in the domestic cycle and suggest the presence of possible bridges between the wildlife cycle and the surrounding domestic cycle. Contribution: The study contributes to identifying transmission patterns and risk factors of T. gondii within human and animal populations. This topic fits within the scope of the journal presenting original research in veterinary science, with the focus on wild and domestic populations on the African continent on a topic of universal importance.
Mostrar más [+] Menos [-]Seroprevalence of brucellosis in communal and smallholder cattle farming in North West Province, South Africa
2023
Bontsi Marumo | Tiny M. Hlokwe | Prudence N. Kayoka-Kabongo
Brucellosis is an important bacterial zoonosis responsible for considerable economic losses in livestock and health-related burden worldwide. The objective of this study was to determine the seroprevalence of brucellosis in communal and smallholder cattle farming in four districts of the North West province of South Africa (Dr Ruth Segomotsi Mompati, Ngaka Modiri Molema, Bojanala platinum and Dr Kenneth Kaunda districts). Seven hundred and seventy blood samples from farmed animals (n = 378) and abattoir-slaughtered animals (n = 392) were collected. In addition, milk samples (n = 22) were collected from lactating farmed cows. Rose Bengal test (RBT), complement fixation test (CFT) and milk ring test (MRT) were used to detect antibodies against Brucella species. The RBT showed a seroprevalence of 2% at 95% confidence interval (CI: 1.35–3.35), CFT confirmed an overall seroprevalence of 1.95% (95% CI: 1.14–3.12) for all four districts sampled. Although the seroprevalence of brucellosis was found to be low, the possibility of undetected cases of the disease could not be ruled out. Overall, the findings of this study confirmed that brucellosis is endemic in the surveyed areas of the North West province of South Africa. Contribution: The outcome of this study will contribute to the National Brucellosis Project organised by the Department of Agriculture, Land Reform and Rural Development (2016–2026) to assist in the effective implementation of the disease control measures with a view to prevent further outbreaks in the country’s cattle population.
Mostrar más [+] Menos [-]Evidence of zoonotic rickettsiae in ixodid ticks of domestic animals in some communal farms in the Eastern Cape Province, South Africa
2024
Olusesan Adeyemi Adelabu | Benson Chuks Iweriebor | Chikwelu Larry Obi
Objective: The abundance of tick populations in South Africa represents a probable risk for both animal and human health. Rickettsia spp. and Borrelia spp. are well-known agents of emerging human tick-borne infectious diseases worldwide. Nevertheless, the epidemiology of their infec¬tions has been underreported in South Africa. Therefore, this study aimed to profile zoonotic Rickettsia and Borrelia species from ticks infesting domesticated animals in the Eastern Cape, South Africa. Materials and Methods: Morphological and molecular identification techniques were conducted on 1,200 tick samples collected from domestic animals before screening for the target bacterial pathogens. The molecular identification of the tick samples was based on the amplification of the 12S rRNA mitochondrial Deoxyribonucleic acid. At the same time, those of Rickettsia and Borrelia species were carried out by amplifying fragments of gltA and ompB genes for Rickettsia and flaB gene for Borrelia spp. Thereafter, the positive amplicons for Rickettsia ompB were sequenced and further analyzed. Borrelia PCRs were negative; therefore, sequencing could not be performed. Results: Eight species of ticks belonging to three genera; Rhipicephalus, Amblyomma, and Haemaphysalis, were identified. A total of 27% (320/1,200) samples were confirmed positive for Rickettsia, of which 23% (74/320) were positive for ompB genes. Phylogenetic analysis of ompB revealed a high homology to rickettsial reference strains from GenBank, with no positive result for Borrelia. The generated sequences showed homology with R. africae-KX227790 (100%), R. parkeri-KY113111 (99.8%), R. peacockii (99.3%), and R. slovaca-JX683122 (99.1%) representative sequences in GenBank. Conclusion: The findings from this study revealed that ticks harbored Rickettsia species with possible zoonotic potential. [J Adv Vet Anim Res 2024; 11(2.000): 254-263]
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