Brucellosis at the Wildlife/Livestock/Human Interface

There are a number of bacterial, viral, and parasitic diseases present at the Wildlife/livestock/human interface. Brucellosis is a zoonotic disease of importance and highly prevalent in sub-Saharan Africa. The important Brucella species at the wildlife/livestock/human interface are Brucella arbortus, Brucella suis, and Brucella melitensis. These species have been isolated from humans, livestock (cattle and goats), and wildlife (African buffalo and giraffe). A lot of studies indicated that density, herd size, age of cow, reduced veterinary services like vaccination programs, and geographical area are associated with Brucella prevalence. Studies in developing countries have indicated that the disease is more prominent in the both commercial and communal farming sectors. Access and consumption of contaminated foods and/or occupational exposure remain the significant source of infection to humans. The pathogen transmission of brucellosis is bidirectional in nature; hence, for control efforts to be successful, cooperation is required between livestock owners, animal health officials, and wildlife managers. Globally, trend is moving toward focusing on “one health,” which recognizes that human, animal (both domestic and wild), and ecosystems are tightly linked. The successful management of disease requires an integrated approach where efforts are focused in concert across these domains. Climate change, increased human populations, and increased interaction at wildlife/livestock/human interface have resulted in the change of brucellosis dynamics

Detection of Brucella abortus in Chiredzi district in Zimbabwe

Brucellosis is an endemic disease in Zimbabwe caused by the genus Brucella. Brucella seroprevalence was recently reported to be high in the wildlife-livestock interface in the Chiredzi district and the neighbouring Gonarezhou National Park (GNP) in Zimbabwe, and higher amongst communal cattle with an abortion history and access to grazing in GNP than amongst communal cattle with no abortion history or access to grazing in GNP. The aim of this study was to investigate Brucella species in brucellosis seropositive cattle in the Chiredzi district with access to GNP using isolation and identification. Isolation of Brucella species from whole blood (n = 18) and milk samples (n = 10) from seropositive animals with an abortion history was based on the rose Bengal test (RBT) and enzyme-linked immunoassays (enzymelinked immunosorbent assay [ELISA]; indirect ELISA and complement ELISA), using microbiology and polymerase chain reaction (PCR) methods. Brucella abortus was cultured and identified from blood and milk collected from seropositive cows in both communal areas. The Brucella-specific 16-23S intergenic spacer (ITS) PCR and multiplex AMOS-PCR assays verified the identification of the cultures. Our results confirmed that B. abortus is present in cattle on communal farms in the Chiredzi district in Zimbabwe and might cause cattle abortions. The need for implementing control measures and raising public awareness on zoonotic transmission of brucellosis are recommended.The Institute of Tropical Medicine (ITM) in Antwerp, Belgium and the National Research Foundation in South Africa.http://www.ojvr.orgam2013ab201

Bovine tuberculosis in Buffaloes, Southern Africa

Funded by European Union Partnership, South East Lowveld Project; Ministere Francais des Affaires Etrangeres; United States Fish and Wildlife Service, Wildlife without Borders, Africa Progra

Relationship between burden of infection in ungulate populations and wildlife/livestock interfaces

In southern African transfrontier conservation areas (TFCAs), people, livestock and wildlife share space and resources in semi-arid landscapes. One consequence of the coexistence of wild and domestic herbivores is the risk of pathogen transmission. This risk threatens local livelihoods relying on animal production, public health in the case of zoonoses, national economies in the context of transboundary animal diseases, and the success of integrated conservation and development initiatives. The level of interaction between sympatric wild and domestic hosts, defining different wildlife/livestock interfaces, characterizes opportunities of pathogen transmission between host populations. Exploring the relationship between infection burden and different types of wildlife/ domestic interfaces is therefore necessary to manage the sanitary risk in animal populations through control options adapted to these multi-host systems. Here, we assessed the infection burdens of sympatric domestic cattle (Bos taurus/Bos indicus) and African buffalo (Syncerus caffer) at an unfenced interface and compared the infection burdens of cattle populations at different wildlife/ livestock interfaces in the Great Limpopo TFCA. Patterns of infection in ungulate populations varied between wild and domestic hosts and between cattle populations at different wildlife/livestock interfaces. Foot-and-mouth disease, Rift Valley fever and theileriosis infections were detected in buffalo and cattle at unfenced interfaces; bovine tuberculosis was only present in buffalo; and brucellosis and lumpy skin disease only in cattle. At unfenced interfaces, cattle populations presented significantly higher Theileria parva and brucellosis prevalence. We hypothesize that cattle populations at wildlife/livestock interfaces face an increased risk of infection compared to those isolated from wildlife, and that the type of interface could influence the diversity and quantity of pathogens shared. Additional host behavioural and molecular epidemiological studies need to be conducted to support this hypothesis. If it is confirmed, the management of wildlife/livestock interfaces will need to be considered through the prism of livestock and public health.The European PARSEL project (No. Food 2007 137-950) and by the Ministère Français des Affaires Etrangères through the French Embassy in Zimbabwe (RP-PCP grants 2008 and 2009).http://journals.cambridge.org/action/displayJournal?jid=HYGam201

Survey of brucellosis at the wildlife–livestock interface on the Zimbabwean side of the Great Limpopo Transfrontier Conservation Area

A cross-sectional study was conducted to determine the seroprevalence of bovine brucellosis in communal cattle and wildlife at a wildlife–livestock interface in the southeast lowveld of Zimbabwe, part of the Great Limpopo Transfrontier Conservation Area. RBT and c-Elisa were used in serial for detection of antibodies against Brucella spp. Between July 2007 and October 2009, a total of 1,158 cattle were tested and the overall seroprevalence of brucellosis was 9.9%. A total of 97 wild animals (African buffaloes (n=47), impala (n=33), kudu (n=16), and giraffe (n=1)) were tested and only one animal (giraffe) was seropositive for brucellosis (1.03%). Brucella seroprevalence showed an increasing trend with age, with adult cattle (>6 years) recording the highest seroprevalence (11.1%), but the differences were not statistically significant. Similarly, female cattle recorded a relatively higher seroprevalence (10.8%) compared to males (7.9%), but the difference was not significant. However, a significant (P<0.001) association between Brucella seropositivity and abortion history was recorded in female cattle. Similarly, Brucella seropositivity was significantly (P<0.01) associated with a history of grazing in the park for female cattle. Overall, from the interface area, cattle with a history of grazing in the park recorded a significantly (P<0.01) higher Brucella seroprevalence (13.5%) compared to those with no history of grazing in the park (4.9%). The significant association between abortion history and seropositivity observed in this study illustrates the potential economic significance of Brucella in cattle in this area. Hence, public awareness and further epidemiological studies of the disease in wildlife, livestock, and humans in the study area are of great importance

Detection of Brucella abortus in Chiredzi district in Zimbabwe

Brucellosis is an endemic disease in Zimbabwe caused by the genus Brucella. Brucella seroprevalence was recently reported to be high in the wildlife-livestock interface in the Chiredzi district and the neighbouring Gonarezhou National Park (GNP) in Zimbabwe, and higher amongst communal cattle with an abortion history and access to grazing in GNP than amongst communal cattle with no abortion history or access to grazing in GNP. The aim of this study was to investigate Brucella species in brucellosis seropositive cattle in the Chiredzi district with access to GNP using isolation and identification. Isolation of Brucella species from whole blood (n = 18) and milk samples (n = 10) from seropositive animals with an abortion history was based on the rose Bengal test (RBT) and enzyme-linked immunoassays (enzymelinked immunosorbent assay [ELISA]; indirect ELISA and complement ELISA), using microbiology and polymerase chain reaction (PCR) methods. Brucella abortus was cultured and identified from blood and milk collected from seropositive cows in both communal areas. The Brucella-specific 16-23S intergenic spacer (ITS) PCR and multiplex AMOS-PCR assays verified the identification of the cultures. Our results confirmed that B. abortus is present in cattle on communal farms in the Chiredzi district in Zimbabwe and might cause cattle abortions. The need for implementing control measures and raising public awareness on zoonotic transmission of brucellosis are recommended

Characterisation of Brucella species in Zimbabwe

Brucellosis is an important zoonotic disease of ruminants, suidae, canids, several wildlife species and humans caused by from the genus Brucella genus consisting of gram-negative bacteria that are facultative intracellular pathogens. Brucellosis is endemic in sub-Saharan African countries, which include Zimbabwe where Brucella abortus and B. melitensis have been reported. In order to control brucellosis, surveillance and identification of Brucella species is of paramount importance. The aim of the study was to carry out a survey of bovine brucellosis using serological tests, PCR assay and characterizing Brucella spp in Zimbabwe using molecular techniques. Serological tests and PCR based assay were used to detect brucellosis in cattle and wildlife in Chiredzi district of Zimbabwe. Blood and serum samples from cattle (n=700) from Chiredzi district (Malipati and Pesvi communal areas), as well as, African buffalo (n=10) and impalas (n=14) (from Gonarezhou National Park (GNP)) were tested for bovine brucellosis using rose bengal test (RBT), serum agglutination methods (SAT) and indirect enzyme linked immunoassays (iELISA). The seroprevalence of bovine brucellosis in cattle was found to be 8.3% using RBT and iELISA and 6.0% using RBT, SAT and iELISA. No antibodies for Brucella spp were detected in the African Buffaloes and impalas. Brucella strains were cultured from milk and blood sample from cows in Chiredzi district. DNA from the two Brucella strains was amplified using the ITS66 and ITS279 primers specific for Brucella 16- 23S rDNA intergenic spacer (ITS) region. This Brucella specific PCR assay was also used to detect Brucella DNA in blood and buffy coat samples from cattle that were seropositive using RBT, SAT and iELISA. Despite the fact that the blood and buffy coat samples were from animals that were bacteriemia since Brucella was isolated from blood and milk and all samples had SAT titres above 148, no Brucella DNA were detected using the specific PCR assay. Furthermore Brucella strains (23) isolated at the Central Veterinary Laboratory (CVL) in Zimbabwe were identified using molecular techniques like MLVA, AMOS-PCR and Bruceladder PCR. Only a few isolates were classified up to species level using bacteriology method (biotyping). MLVA-16 was able to identify B. abortus, B. melitensis, B. ovis and B. suis strains amongst Zimbabwean isolates. The latter two species is the first report of these species in Zimbabwe. The MLVA assay furthermore indicated that some Zimbabwean isolates significantly differ from isolates of other origin in specific species clusters. These Zimbabwean isolates could not be speciated and future research using bacteriology and molecular characterization are necessary to characterize these isolates. A few strains identified using bacteriological methods and MLVA were also verified using AMOS-PCR and Bruceladder. For these results it is clear that MLVA, AMOS-PCR and Bruceladder can be used to identify Brucella species and biovars and can therefore contribute towards the control of brucellosis in African countries.Dissertation (MSc)--University of Pretoria, 2011.Veterinary Tropical DiseasesUnrestricte

A survey of Tuberculosis and Brucellosis in wildlife and cattle in the South-East Lowveld of Zimbabwe

The work was conducted within the framework of the “Research Platform Production and Conservation in Partnership†(RP-PCP),A cross-sectional study was conducted to determine the seroprevalence of bovine brucellosis and the prevalence of bovine tuberculosis (bTB) in cattle and wildlife at a wildlife-livestock interface in the south-east lowveld of Zimbabwe. Study areas were selected to include those with close proximity to wildlife from GNP and KNP and those without a wildlife-livestock interface area. For both cattle and wildlife, sera were screened for anti-Brucella antibodies using the Rose Bengal test as a presumptive test and the competitive-ELISA as a confirmatory test. The Single Comparative Intradermal Tuberculin Skin Test was used to identify reactor cattle for bTB and positive animals were confirmed using the gamma interferon test, culture and histopathology. For wildlife, bTB was tested in African buffaloes by using the gamma interferon test, culture and histopathology. Age, sex, location, abortion and grazing history were considered as risk factors for Brucella seropositivity while age, sex, location and grazing history were considered as risk factors for bTB in cattle. A total of 1158 cattle were tested and the overall seroprevalence of brucellosis was 9.9%. A total of 97 wild animals (47 buffaloes, 33 impala, 16 kudu, and 1 giraffe) were tested and only one animal (giraffe) (1%) was seropositive for brucellosis. In the interface area, cattle with a history of grazing in the park recorded a significantly (P<0.05) higher Brucella seroprevalence (13.5%) compared to those with no history of grazing in the park (4.9%). A total of 477 cattle were tested for bTB and only five (1%) reactors were recorded. The five cattle reactors were all found to be negative on the confirmatory test, culture and histopathology. Of the 38 buffaloes tested for bTB and 4 (10.5%) were positive and bacterial culture of two gamma interferon-positive buffaloes yielded Mycobacterium bovis. The results of the present study established the presence of brucellosis in communal cattle in the studied areas and of bTB in GNP African buffaloes for the first time.,French Agricultural Research Centre for International Development (CIRAD) in Zimbabwe ,the Ministere Francais de Affaires Etrangeres and the French Embassy in Zimbabwe (RP-PCP grant/project AHE#1 2007 to 2009)

A survey of Tuberculosis and Brucellosis in wildlife and cattle in the South-East Lowveld of Zimbabwe

A cross-sectional study was conducted to determine the seroprevalence of bovine brucellosis and the prevalence of bovine tuberculosis (bTB) in cattle and wildlife at a wildlife-livestock interface in the south-east lowveld of Zimbabwe. Study areas were selected to include those with close proximity to wildlife from GNP and KNP and those without a wildlife-livestock interface area. For both cattle and wildlife, sera were screened for anti-Brucella antibodies using the Rose Bengal test as a presumptive test and the competitive-ELISA as a confirmatory test. The Single Comparative Intradermal Tuberculin Skin Test was used to identify reactor cattle for bTB and positive animals were confirmed using the gamma interferon test, culture and histopathology. For wildlife, bTB was tested in African buffaloes by using the gamma interferon test, culture and histopathology. Age, sex, location, abortion and grazing history were considered as risk factors for Brucella seropositivity while age, sex, location and grazing history were considered as risk factors for bTB in cattle. A total of 1158 cattle were tested and the overall seroprevalence of brucellosis was 9.9%. A total of 97 wild animals (47 buffaloes, 33 impala, 16 kudu, and 1 giraffe) were tested and only one animal (giraffe) (1%) was seropositive for brucellosis. In the interface area, cattle with a history of grazing in the park recorded a significantly (P<0.05) higher Brucella seroprevalence (13.5%) compared to those with no history of grazing in the park (4.9%). A total of 477 cattle were tested for bTB and only five (1%) reactors were recorded. The five cattle reactors were all found to be negative on the confirmatory test, culture and histopathology. Of the 38 buffaloes tested for bTB and 4 (10.5%) were positive and bacterial culture of two gamma interferon-positive buffaloes yielded Mycobacterium bovis. The results of the present study established the presence of brucellosis in communal cattle in the studied areas and of bTB in GNP African buffaloes for the first time