Occurrence, serotypes and virulence characteristics of Shiga toxin-producing and Enteropathogenic Escherichia coli isolates from dairy cattle in South Africa.

Shiga toxin-producing and Enteropathogenic Escherichia coli are foodborne pathogens commonly associated with diarrheal disease in humans. This study investigated the presence of STEC and EPEC in 771 dairy cattle fecal samples which were collected from 5 abattoirs and 9 dairy farms in South Africa. STEC and EPEC were detected, isolated and identified using culture and PCR. Furthermore, 339 STEC and 136 EPEC isolates were characterized by serotype and major virulence genes including stx1, stx2, eaeA and hlyA and the presence of eaeA and bfpA in EPEC. PCR screening of bacterial sweeps which were grown from fecal samples revealed that 42.2% and 23.3% were STEC and EPEC positive, respectively. PCR serotyping of 339 STEC and 136 EPEC isolates revealed 53 different STEC and 19 EPEC serotypes, respectively. The three most frequent STEC serotypes were O82:H8, OgX18:H2, and O157:H7. Only 10% of the isolates were classified as "Top 7" STEC serotypes: O26:H2, 0.3%; O26:H11, 3.2%; O103:H8, 0.6%; and O157:H7, 5.9%. The three most frequent EPEC serotypes were O10:H2, OgN9:H28, and O26:H11. The distribution of major virulence genes among the 339 STEC isolates was as follows: stx1, 72.9%; stx2, 85.7%; eaeA, 13.6% and hlyA, 69.9%. All the 136 EPEC isolates were eaeA-positive but bfpA-negative, while 46.5% carried hlyA. This study revealed that dairy cattle are a major reservoir of STEC and EPEC in South Africa. Further comparative studies of cattle and human STEC and EPEC isolates will be needed to determine the role played by dairy cattle STEC and EPEC in the occurrence of foodborne disease in humans.Please kindly check and confirm the country and city name in affiliation [6].This affiliation is correct.Please kindly check and confirm the affiliationsConfirmed. All Affiliations are accurate.

Tracing cross species transmission of Mycobacterium bovis at the wildlife/livestock interface in South Africa.

BACKGROUND: Bovine tuberculosis (bTB) affects cattle and wildlife in South Africa with the African buffalo (Syncerus caffer) as the principal maintenance host. The presence of a wildlife maintenance host at the wildlife/livestock interface acting as spill-over host makes it much more challenging to control and eradicate bTB in cattle. Spoligotyping and mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) genotyping methods were performed to investigate the genetic diversity of Mycobacterium bovis (M. bovis) isolates from cattle and wildlife, their distribution and transmission at the wildlife/livestock interface in northern Kwa-Zulu Natal (KZN), South Africa. RESULTS: SB0130 was identified as the dominant spoligotype pattern at this wildlife/livestock interface, while VNTR typing revealed a total of 29 VNTR profiles (strains) in the KZN province signifying high genetic variability. The detection of 5 VNTR profiles shared between cattle and buffalo suggests M. bovis transmission between species. MIRU-VNTR confirmed co-infection in one cow with three strains of M. bovis that differed at a single locus, with 2 being shared with buffalo, implying pathogen introduction from most probably unrelated wildlife sources. CONCLUSION: Our findings highlight inter and intra species transmission of bTB at the wildlife/livestock interface and the need for the implementation of adequate bTB control measures to mitigate the spread of the pathogen responsible for economic losses and a public health threat.

Occurrence and Antimicrobial Resistance Profiles of Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis in Beef Cattle on Cow-Calf Operations in South Africa.

This study investigated occurrence and antimicrobial resistance profiles of Campylobacter spp. isolates in beef cattle on five cow-calf operations in South Africa. A total of 537 fecal samples from adult beef cattle (n = 435) and rectal swabs from calves (n = 102) were screened for Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis by culture and polymerase chain reaction. Furthermore, 86 Campylobacter spp. isolates including 46 C. jejuni, 24 C. coli, and 16 C. upsaliensis were tested for antimicrobial resistance against a panel of 9 antimicrobials. Overall, Campylobacter spp. was detected in 29.7% of cattle. Among the 158 Campylobacter spp.-positive cattle, 61.8% carried C. jejuni, 25% carried C. coli, and 10% carried C. upsaliensis. Five animals (3.1%) had mixed infections: three cows carried C. jejuni and C. coli concurrently, one cow had both C. jejuni and C. upsaliensis, and one cow harbored C. coli and C. upsaliensis. Antimicrobial resistance profiling among 86 Campylobacter spp. isolates revealed that 52.3% of the isolates were resistant to one or more antimicrobials. Antimicrobial resistance was observed in 46.7% of C. jejuni isolates, 35.6% of C. coli, and 17.8% of C. upsaliensis. Thirty-six percent of isolates were resistant to clindamycin, 19.7% to nalidixic acid, 18.6% to tetracycline, and 17.4% to erythromycin. Lower resistance rates were recorded for azithromycin (8.1%), florfenicol (3.4%), gentamicin (4.8%), and telithromycin and ciprofloxacin (5.8%). Multidrug resistance (MDR) was observed in 32.5% of isolates. Significantly higher levels of MDR were detected among C. jejuni (36.9%) and C. coli (33.3%) isolates in comparison to C. upsaliensis (18.7%). Two main multiresistance patterns were detected: nalidixic acid/clindamycin (17.8%) and tetracycline/clindamycin (14.2%). To the best of our knowledge, this is the first study which has shown that beef cattle on cow-calf operations in South Africa constitute an important reservoir and a potential source of clinically relevant and antimicrobial resistant Campylobacter spp. strains.

Spatial and seasonal patterns of FMD primary outbreaks in cattle in Zimbabwe between 1931 and 2016.

Foot and mouth disease (FMD) is an important livestock disease impacting mainly intensive production systems. In southern Africa, the FMD virus is maintained in wildlife and its control is therefore complicated. However, FMD control is an important task to allow countries access to lucrative foreign meat market and veterinary services implement drastic control measures on livestock populations living in the periphery of protected areas, negatively impacting local small-scale livestock producers. This study investigated FMD primary outbreak data in Zimbabwe from 1931 to 2016 to describe the spatio-temporal distribution of FMD outbreaks and their potential drivers. The results suggest that: (i) FMD outbreaks were not randomly distributed in space across Zimbabwe but are clustered in the Southeast Lowveld (SEL); (ii) the proximity of protected areas with African buffalos was potentially responsible for primary FMD outbreaks in cattle; (iii) rainfall per se was not associated with FMD outbreaks, but seasons impacted the temporal occurrence of FMD outbreaks across regions; (iv) the frequency of FMD outbreaks increased during periods of major socio-economic and political crisis. The differences between the spatial clusters and other areas in Zimbabwe presenting similar buffalo/cattle interfaces but with fewer FMD outbreaks can be interpreted in light of the recent better understanding of wildlife/livestock interactions in these areas. The types of wildlife/livestock interfaces are hypothesized to be the key drivers of contacts between wildlife and livestock, triggering a risk of FMD inter-species spillover. The management of wildlife/livestock interfaces is therefore crucial for the control of FMD in southern Africa.

Antimicrobial Resistance Trends in Escherichia coli in South African Poultry: 2009-2015.

Prolonged and widespread in-feed use of antimicrobials as either growth promoters or to treat bacterial infections in commercial poultry production contributed to the emergence of resistant bacterial strains globally. A total of 3544 avian pathogenic Escherichia coli strains isolated from commercial broilers in South Africa between 2009 and 2015 were tested for susceptibility against eight classes of antimicrobials. Time series analyses were conducted to assess seasonal and general trends in antibiotic resistance. Seasonal trends were seen in the tetracyclines, with peaks of resistance in the winter months when respiratory diseases are at their worst. Resistance to quinolones peaked in 2012 after which there was an overall decreasing trend in resistance. Colistin resistance increased gradually from 2009 with a drastic rise to 12.08% in 2015, but its use in feed was stopped in 2016. Florfenicol also showed a sharp increase in resistance from 2.36% in 2009 to 6.63% in 2015. Resistance to trimethoprim-sulphadiazine decreased sharply by the end of 2015, as did spectinomycin and fosfomycin and amoxicillin. The overall prevalence of multidrug resistance (MDR) was 80.6 (95% confidence interval, 0.743-0.819), but the years 2013, 2014, and 2015 showed a significantly lower level of MDR compared with 2009. This study is the first detailed analysis of antimicrobial resistance in poultry production in the country, and constant monitoring of resistance data should be continued to aid in the judicious use of antimicrobial compounds.

Whole-Genome Sequencing of Human and Porcine Escherichia coli Isolates on a Commercial Pig Farm in South Africa.

Escherichia coli is an indicator micro-organism in One Health antibiotic resistance surveillance programs. The purpose of the study was to describe and compare E. coli isolates obtained from pigs and human contacts from a commercial farm in South Africa using conventional methods and whole-genome sequencing (WGS). Porcine E. coli isolates were proportionally more resistant phenotypically and harbored a richer diversity of antibiotic resistance genes as compared to human E. coli isolates. Different pathovars, namely ExPEC (12.43%, 21/169), ETEC (4.14%, 7/169), EPEC (2.96%, 5/169), EAEC (2.96%, 5/169) and STEC (1.18%, 2/169), were detected at low frequencies. Sequence type complex (STc) 10 was the most prevalent (85.51%, 59/169) among human and porcine isolates. Six STcs (STc10, STc86, STc168, STc206, STc278 and STc469) were shared at the human-livestock interface according to multilocus sequence typing (MLST). Core-genome MLST and hierarchical clustering (HC) showed that human and porcine isolates were overall genetically diverse, but some clustering at HC2-HC200 was observed. In conclusion, even though the isolates shared a spatiotemporal relationship, there were still differences in the virulence potential, antibiotic resistance profiles and cgMLST and HC according to the source of isolation.

Antimicrobial growth promoters approved in food-producing animals in South Africa induce shiga toxin-converting bacteriophages from Escherichia coli O157:H7.

In this study, four antimicrobial growth promoters, including virginiamycin, josamycin, flavophospholipol, poly 2-propenal 2-propenoic acid and ultraviolet light, were tested for their capacity to induce stx-bacteriophages in 47 Shiga toxin-producing E. coli O157:H7 isolates. Induced bacteriophages were characterized for shiga toxin subtypes and structural genes by PCR, DNA restriction fragment length polymorphisms (RFLP) and morphological features by electron microscopy. Bacteriophages were induced from 72.3% (34/47) of the STEC O157:H7 isolates tested. Bacteriophage induction rates per induction method were as follows: ultraviolet light, 53.2% (25/47); poly 2-propenal 2-propenoic acid, 42.6% (20/47); virginiamycin, 34.0% (16/47); josamycin, 34.0% (16/47); and flavophospholipol, 29.8% (14/47). A total of 98 bacteriophages were isolated, but only 59 were digestible by NdeI, revealing 40 RFLP profiles which could be subdivided in 12 phylogenetic subgroups. Among the 98 bacteriophages, stx2a, stx2c and stx2d were present in 85.7%, 94.9% and 36.7% of bacteriophages, respectively. The Q, P, CIII, N1, N2 and IS1203 genes were found in 96.9%, 82.7%, 69.4%, 40.8%, 60.2% and 73.5% of the samples, respectively. Electron microscopy revealed four main representative morphologies which included three bacteriophages which all had long tails but different head morphologies: long hexagonal head, oval/oblong head and oval/circular head, and one bacteriophage with an icosahedral/hexagonal head with a short thick contractile tail. This study demonstrated that virginiamycin, josamycin, flavophospholipol and poly 2-propenal 2-propenoic acid induce genetically and morphologically diverse free stx-converting bacteriophages from STEC O157:H7. The possibility that these antimicrobial growth promoters may induce bacteriophages in vivo in animals and human hosts is a public health concern. Policies aimed at minimizing or banning the use of antimicrobial growth promoters should be promoted and implemented in countries where these compounds are still in use in animal agriculture.

Method to Assess Farm-Level Vaccine and Antibiotic Usage Utilizing Financial Documentation: A Pilot Study in a Commercial Pig Farm in South Africa From 2016 to 2018.

The purpose of the study was to develop a blueprint using financial documentation to describe and quantify vaccine and antibiotic usage (ABU). This method was piloted in a commercial pig farm in South Africa, with the ultimate hope to serve as a tool in a future species-specific vaccine and ABU surveillance system. Data collection was based on templates from the European Surveillance of Veterinary Antimicrobial Consumption (ESVAC) network and the World Organisation for Animal Health (WOAH). Invoices from 2016 to 2018 were used as the main data source. In addition, monthly statement of accounts were used to check for missing invoices. An inventory check was done to ensure that the correct antibiotic concentrations were used in subsequent calculations. Livestock counts and slaughter statistics were also collected to be used as denominator data. Cost calculations for the procurement of antibiotics and vaccines were also done. The study showed that veterinary medicinal products were purchased only from a single veterinary practice. A total of 291 invoices were issued over 3 years, of which 2.75% (8/291) were missing and could therefore not be used in quantification. Tetracyclines (453.65 ± 25.49 kg and 135.16 ± 3.31 mg/kg), followed by quinoxalines (258.33 ± 8.04 kg and 77.07 ± 3.93 mg/kg) were used in the highest amounts, both in terms of weight (kg) and adjusted for animal biomass (mg/kg). Vaccines used on the farm targeted seven different diseases, namely enzootic pneumonia, erysipelas, ileitis, infectious infertility, leptospirosis, neonatal pig diarrhea and porcine circovirus disease. An average of 103 546 vaccine dosages was purchased for ZAR1 302,727 ($ 84,620) per year, whereas the average cost for the procurement of antibiotics was ZAR 907,372 ($ 69,561) per year. The study showed that invoices and monthly statement of accounts, in combination with an inventory check and on-farm production statistics, are useful data sources to quantify vaccine and ABU in the absence of veterinary prescriptions. In addition, vaccinating pigs were more expensive than administering antibiotics.

Prioritisation of Provinces for African Swine Fever Intervention in South Africa through Decision Matrix Analysis.

South Africa has experienced an increase in the number of African swine fever (ASF) outbreaks in domestic pigs in the last ten years. Intervention will be needed in the form of control and prevention strategies to minimise the impact of this disease in the country. The aim of this study is to prioritise which provinces resources should be allocated to for ASF intervention strategies, based on the risk factors identified as pertinent in South Africa. A multi-criteria decision analysis approach was followed using an analytic hierarchy process (AHP) method to determine the perceived risk of ASF outbreaks in domestic pigs per province. Nine risk factors applicable to the South African context were identified from literature. Data on the presence of these risk factors per province were collected from records and by means of a questionnaire. The risk factors were weighted by means of an AHP. The decision matrix determined that ASF intervention and prevention resources should be focused on Mpumalanga, Free State and Gauteng provinces in South Africa. Specific intervention strategies should be focused on the confinement of pigs, swill-feeding of pigs and buying/selling of pigs at auctions through a participatory approach with stakeholders.

Spatio-temporal clustering and risk factor analysis of bovine theileriosis (Theileria parva) in Zimbabwe from 1995 to 2018.

Bovine theileriosis (caused by Theileria parva) is the most important tick-borne transboundary animal disease endemic to Zimbabwe, yet its distribution dynamics data in the country remain scant and outdated. A retrospective study was conducted to determine high-risk areas of bovine theileriosis and associated risk factors in Zimbabwe. Records on bovine theileriosis spanning 23 years (January 1995 to December 2018) were obtained from the Epidemiological Unit of the Division of Field Veterinary Services of Zimbabwe (DVSZ). Data were analysed using Studio R® version 11.0 for regression analysis and SatScan® version 9.4.6 for spatio-temporal clustering. Communal farmers (72%), adult cattle (29%), the year 2018 (60%) and the hot wet season (42%) had the highest proportion (p < .050) of bovine theileriosis cases recorded. Seven out of the country's ten provinces and 36 of its 59 districts were affected. Bovine theileriosis was observed to lose seasonality when cases rose exponentially in 2018. Five and four high-risk clusters of bovine theileriosis were detected using one-year and one-month time aggregate, respectively, all within the last eight years of the study (2011-2018). Two potential risk factors (province and farming system) were significantly (p < .050) associated with bovine theileriosis occurrence. Bovine theileriosis was found to be rampant and if left unchecked will spread and adversely affect the whole country. Improved theileriosis surveillance and control is warranted. Recommendations for control and prevention strategies revolve around better farmer awareness about the disease, correct and consistent use of acaricides, cattle movement control and disease surveillance among others.

Knowledge, Attitudes, and Practices of Communal Livestock Farmers regarding Animal Health and Zoonoses in Far Northern KwaZulu-Natal, South Africa.

The presence of zoonotic diseases adversely affects livestock production and farmers' livelihood in communal areas. A lack of awareness about zoonotic diseases among rural farmers results in economic losses and health risks. The far north-eastern corner of KwaZulu-Natal (KZN) province, South Africa, is home to large numbers of communal livestock farmers who live adjacent to wildlife reserves and international borders. There have been reports of zoonotic and trade-sensitive diseases in the area, but farmers' knowledge, attitudes, and practices (KAP) in this regard are poorly understood. This study investigated the KAPs of communal livestock farmers in far northern KZN regarding livestock and zoonotic diseases found in the livestock-wildlife interface and determined the constraints and challenges faced by communal livestock farmers. A cross-sectional questionnaire survey was conducted among 504 livestock farmers at 45 dip tanks between August and November 2020, using a closed-ended questionnaire. Although the overall level of knowledge regarding animal disease transmission was fairly good (score: 53.2%), 25.4% and 21.4% of farmers had moderate and poor knowledge, respectively, about zoonotic disease transmission and prevention. Over 40% of the farmers were not aware of the zoonotic nature of wildlife and livestock diseases. Older farmers, despite their lower level of education, were more knowledgeable on animal diseases and had better practices in regard to zoonotic disease prevention and management compared to younger ones. The majority of farmers cited the lack of water, insufficient grazing land, stock theft, the restriction of animal movement, and animal diseases as the most significant challenges they faced regarding animal production. The results indicate the need for extension programs that target educating livestock farmers to improve their knowledge of these diseases.

Occurrence, Serotypes and Virulence Characteristics of Shiga-Toxin-Producing Escherichia coli Isolates from Goats on Communal Rangeland in South Africa.

Shiga-toxin-producing Escherichia coli is a foodborne pathogen commonly associated with human disease characterized by mild or bloody diarrhea hemorrhagic colitis and hemolytic uremic syndrome. This study investigated the occurrence of STEC in fecal samples of 289 goats in South Africa using microbiological culture and PCR. Furthermore, 628 goat STEC isolates were characterized by serotype (O:H) and major virulence factors by PCR. STEC was found in 80.2% (232/289) of goat fecal samples. Serotyping of 628 STEC isolates revealed 63 distinct serotypes including four of the major top seven STEC serogroups which were detected in 12.1% (35/289) of goats: O157:H7, 2.7% (8/289); O157:H8, 0.3%, (1/289); O157:H29, 0.3% (1/289); O103:H8, 7.6% (22/289); O103:H56, 0.3% (1/289); O26:H2, 0.3% (1/289); O111:H8, 0.3% (1/289) and 59 non-O157 STEC serotypes. Twenty-four of the sixty-three serotypes were previously associated with human disease. Virulence genes were distributed as follows: stx1, 60.6% (381/628); stx2, 72.7% (457/628); eaeA, 22.1% (139/628) and hlyA, 78.0% (490/628). Both stx1 and stx2 were found in 33.4% (210/628) of isolates. In conclusion, goats in South Africa are a reservoir and potential source of diverse STEC serotypes that are potentially virulent for humans. Further molecular characterization will be needed to fully assess the virulence potential of goat STEC isolates and their capacity to cause disease in humans.

Spatio-temporal patterns and risk factors of foot-and-mouth disease in Malawi between 1957 and 2019.

Foot-and-mouth disease (FMD) is an important livestock disease causing short-term and long-term production losses and hindering local and international trade. To gain access to lucrative foreign markets and also improve local trade, there is a need to employ effective preventive and control strategies. Although FMD has been present in Malawi for over 60 years, little knowledge is available concerning the dynamics and drivers of FMD in the country. A modelling study based on retrospective data was conducted to establish the spatio-temporal distribution and determine the risk factors associated with FMD in Malawi. A retrospective space-time analysis was performed and a matched case-control study was carried out to investigate risk factors. The number of reported FMD outbreaks has descriptively increased after 2000 and the disease has spread to previously unaffected areas. Two significant spatio-temporal clusters of FMD were identified; one in the southern region and the other in the northern region. An analysis of only index cases (first detected locations) also detected two clusters with one in the northern region and the other in the southern region. Higher beef cattle density (p = 0.023), higher pig density (p = 0.043) and increased distance to wildlife protected areas (p = 0.036) were positively associated with the risk of FMD while increased distances to international borders (p = 0.008) and roads (p = 0.034) were associated with reduced risk of FMD. High FMD risk areas were observed in the southern and northern regions but not in the central region during the early years (1957-1981). The more recent increase in FMD risk at the end of the study period (2019) in the central region might be attributed to increases in livestock density in this region. These findings provide insight into the pattern of FMD occurrence that will promote informed decisions for the progressive control of FMD in the region.

Seroprevalence of African swine fever in Senegal, 2006.

In Senegal, during 2002-2007, 11 outbreaks of African swine fever (ASF) were reported to the World Organisation for Animal Health. Despite this, little was known of the epidemiology of ASF in the country. To determine the prevalence of ASF in Senegal in 2006, we tested serum specimens collected from a sample of pigs in the 3 main pig-farming regions for antibodies to ASF virus using an ELISA. Of 747 serum samples examined, 126 were positive for ASF, suggesting a prevalence of 16.9%. The estimated prevalences within each of the regions (Fatick, Kolda, and Ziguinchor) were 13.3%, 7.8%, and 22.1%, respectively, with statistical evidence to suggest that the prevalence in Ziguinchor was higher than in Fatick or Kolda. This regional difference is considered in relation to different farming systems and illegal trade with neighboring countries where the infection is endemic.

Review of African swine fever outbreaks history in South Africa: From 1926 to 2018.

The article reviews the outbreaks and distribution of African swine fever (ASF) in South Africa since the first probable outbreak that occurred in the Koedoesrand Ward in 1926. Retrospective data on the ASF outbreaks in South Africa were obtained from the World Organisation for Animal Health (OIE) disease database and the South African veterinary services annual reports in addition to published articles and online sources. South Africa has experienced many outbreaks that can be divided into 2 time periods: the period before the development of the OIE diseases database (1993) and the period after. More than 141 outbreaks of ASF were reported during the first period. Since the development of OIE disease database, 72 outbreaks directly involving 2968 cases, 2187 dead and 2358 killed pigs mainly in smallholder pig farms were reported. The median number of cases for a given ASF outbreak is 17, but in 50% of outbreaks no pigs were killed for prevention. The most important ASF outbreak was reported in April 2014 in the Greater Zeerust district (North West province) involving 326 cases and 1462 killed pigs. However, the outbreak with highest mortality involving 250 pigs was reported in 2016 (Free State province). According to phylogenetic analysis, nine p72 genotypes (I, III, IV, VII, VIII, XIX, XX, XXI and XXII) have been identified in South Africa. Season-wise, more outbreaks were recorded during summer. It was also observed that the OIE disease database could contain errors that would have been introduced through compiled forms at country level. Spatiotemporal studies on ASF outbreaks in South Africa are therefore required in order to assess statistically and quantitatively the clustering of outbreaks over space and time.

Progressive Area Elimination of Bovine Brucellosis, 2013-2018, in Gauteng Province, South Africa: Evaluation Using Laboratory Test Reports.

Bovine brucellosis is a zoonotic disease of global public health and economic importance. South Africa has had a national bovine brucellosis eradication scheme since 1979; however, no published report on elimination progress from any province exists. We analysed laboratory test results of all cattle herds participating in the Gauteng Provincial Veterinary Services' eradication scheme between 2013 and 2018. Herd reactor status and within-herd seroprevalence, modelled using mixed-effects logistic and negative binomial regression models, respectively, showed no significant change over the period. However, provincial State Vet Areas, Randfontein (OR = 1.6; 95% CI: 1.2-2.1; p < 0.001) and Germiston (OR = 1.9; 95% CI: 1.5-2.5, p = 0.008) had higher odds of reactor herds than the Pretoria Area and within-herd prevalence count ratios for these areas were 1.5-fold greater than the Pretoria State Vet Area (p < 0.001). Reactor herds were associated with increased herd size (p < 0.001) and larger herd sizes were associated with lower within-herd prevalence (p < 0.001). Despite no evidence of significant progress toward bovine brucellosis elimination in Gauteng province, variability in bovine brucellosis prevalence between State Vet Areas exists. A public health and farmer-supported strategy of ongoing district-based surveillance and cattle vaccination targeting small- to medium-sized herds combined with compulsory test and slaughter of reactors in larger herds is recommended for the province.

Do wild suids from Ndumo Game Reserve, South Africa, play a role in the maintenance and transmission of African swine fever to domestic pigs?

Warthogs (Phacochoerus africanus) and bushpigs (Potamochoerus larvatus) are considered as the wild reservoirs of ASF. They are both present in Ndumo Game Reserve (NGR), located in the Northern South African Province of KwaZulu on the border with Mozambique. In that area, the occurrence of tick-warthog sylvatic cycle of ASF has been suspected for years. To assess if wild suids represent a risk of ASF virus spillover to domestic pigs, wild suid abundance and incursions outside NGR boundaries were estimated using transect counts, fence patrols and camera traps. Also, the presence of Ornithodoros ticks was explored in 35 warthog burrows within NGR. In addition, blood samples were taken from 67 domestic pig farms located outside NGR to be tested for ASF antibodies. Information on interactions between domestic and wild suids and ASF occurrence was gathered using interviews with pig farmers (n = 254) in the study area. In conclusion, the bushpigs and warthog's population estimates in NGR are 5 and 3-5 individuals/km2 , respectively. Both species move out of the reserve regularly (15.4 warthogs/day and 6.35 bushpigs/day), with movements significantly increasing in the dry season. Some farmers observed warthogs and bushpigs as far as 8 and 19 km from NGR, respectively, but no reports of direct wild-domestic suids interactions or ASF outbreaks. Also, no soft ticks were detected in all warthog burrows and all the pig blood samples were negative for ASF antibodies. The absence of ticks in warthog burrows, the absence of antibodies in pigs sampled, the absence of reported outbreaks, and no familiarity with ASF in the study area, suggest that a sylvatic cycle of ASF is, at present, unlikely in NGR. This conclusion must be confirmed by a larger survey of warthog burrows and monitoring potential antibodies in warthogs from NGR.

Knowledge of Brucellosis, Health-Seeking Behaviour, and Risk Factors for Brucella Infection amongst Workers on Cattle Farms in Gauteng, South Africa.

Brucellosis in humans is under-detected and underreported in sub-Saharan Africa. Risk factors associated with Brucella infection and health seeking behaviour in response to brucellosis-like symptoms, amongst cattle farm workers and veterinary officials in South Africa, are unknown. Farm workers and veterinary officials (N = 230) were screened for brucellosis using commercial Rose Bengal Test (RBT®), IgM Enzyme-linked Immunoassay (ELISA)®, IgG ELISA® and the BrucellaCapt® test. Knowledge of brucellosis and risk factors for exposure to Brucella were also investigated. Seroprevalence varied according to test used: 10.1% (RBT®), 20.9% (IgG ELISA®) and 6.5% (BrucellaCapt®). Only 22.2% (6/27) of veterinary officials opt to visit a clinic, doctor, or hospital in response to self-experienced brucellosis-like symptoms, compared to 74.9% (152/203) of farm workers (p < 0.001). Of the BrucellaCapt® seropositive participants, 53% (7/15) did not visit a clinic in response to brucellosis-like symptoms. Weak evidence of an association between the handling of afterbirth or placenta and infection of a short evolution (RBT®, IgM ELISA® and IgG ELISA® seropositive) was found (OR = 8.9, 95% CI: 1.0-81.1, p = 0.052), and strong evidence of an association between this outcome and the slaughter of cattle (OR = 5.3, 95% CI: 1.4-19.6, p = 0.013). There was strong evidence of a positive association between inactive/resolved infection and veterinary officials vs. farm workers exposed to seropositive herds (OR = 7.0, 95% CI: 2.4-20.2, p < 0.001), with a simultaneous negative association with the handling of afterbirth or placenta (OR = 3.9, 95% CI: 1.3-11.3, p = 0.012). Findings suggest a proportion of undetected clinical cases of brucellosis amongst workers on cattle farms in Gauteng.

Bovine Brucellosis in Gauteng, South Africa: Seroprevalence amongst Cattle Handlers and Variables Associated with Seropositive Cattle Herds, 2014-2016.

In South Africa, the prevalence of cattle handler exposure to Brucella on cattle farms is unknown and risk factors and cattle symptoms associated with infected cattle herds are unavailable. To address this gap, a case-control study of cattle herds was conducted in Gauteng province and farm workers and veterinary officials were tested for exposure to Brucella. Seroprevalence amongst farm workers exposed to case herds ranged from 4.0% (BrucellaCapt®) to 16.7% (IgG ELISA®), compared to those exposed to control herds, where seroprevalence ranged from 1.9% (BrucellaCapt®) to 5.7% (IgG ELISA®). Seroprevalence amongst veterinary officials was significantly greater compared to farm workers exposed to case herds for the outcome RBT+ IgM- IgG+ (OR = 11.1, 95% CI: 2.5-49.9, p = 0.002) and RBT- IgM- IgG+ (OR = 6.3, 95% CI: 2.3-17.3, p < 0.001). Risk factors associated with being an infected herd were: being a government-sponsored farm vs. private farm (OR 4.0; 95% CI: 1.4-11.3; p = 0.009), beef vs. dairy herd (OR 7.9; 95% CI: 1.4-44.9; p = 0.020), open vs. closed herd (OR 3.3; 95% CI: 1.1-10.4; p = 0.038) and the presence of antelope on the farm (OR 29.4; 95% CI: 4.0-218.2; p = 0.001). Abortions (OR = 5.1; 95% CI: 2.0-13.3; p < 0.001), weak calves in the herd (OR = 8.0; 95% CI: 2.6-24.4; p < 0.001), reduction in number of calves born (OR = 9.0; 95% CI: 2.1-43.6; p < 0.001), reduction in conception rate (OR = 3.9; 95% CI: 0.8-18.3; p = 0.046), hygromas in cattle (p = 0.011) and farmers reporting brucellosis-like symptoms in their farm workers or in him/herself (OR = 3.4; 95% CI: 1.3-8.7; p = 0.006) were more likely to be associated with Brucella infected herds than control herds. This evidence can be used in strategic planning to protect both human and herd health.

A one health investigation of pathogenic trypanosomes of cattle in Malawi.

Parasitic protozoan trypanosomes of the genus Trypanosoma cause infections in both man and livestock in Africa. Understanding the current spatial distribution of trypanosomes, herd-level factors associated with Trypanosoma brucei infection as well as local knowledge of African trypanosomosis is key to its prevention and control. A cross-sectional study was performed that sampled 53 livestock farmers and 444 cattle throughout Malawi. Cattle were screened for trypanosomes using serology and molecular techniques. Questionnaires were administered to livestock herders and incidence of hospital diagnosed human trypanosome infections was estimated from reports submitted to the Department of Health Unit. The apparent prevalence of trypanosome species based on molecular detection was low for Trypanosoma brucei (2%; 95 % CI: 1-4 %) and Trypanosoma congolense (3%; 95 % CI: 2-5 %) but higher for Trypanosoma theileri (26 %; 95 % CI: 22-30 %). The central region of the country was identified as being at a higher risk of T.brucei infection. One of the sampled cattle was confirmed as being infected with Trypanosoma brucei rhodesiense. Human trypanosome cases were more frequently reported in the northern region with an estimated incidence of 5.9 cases per 100,000 people in Rumphi District. The control of zoonotic diseases that impact poor livestock herders requires a One Health approach due to the close contact between humans and their animals and the reliance on animal production for a sustainable livelihood.