A comparison of risk factor investigation and experts' opinion elicitation analysis for identifying foot-and-mouth disease (FMD) high-risk areas within the FMD protection zone of South Africa (2007-2016).

Foot-and-mouth disease is a controlled disease in accordance with the South African Animal Diseases Act (Act 35 of 1984). The country was classified by the World Organisation for Animal Health (WOAH) as having a FMD free zone without vaccination in 1996. However, this status was suspended in 2019 due to a FMD outbreak outside the controlled zones. FMD control in South Africa includes animal movement restrictions placed on cloven-hoofed species and products, prophylactic vaccination of cattle, clinical surveillance of susceptible species, and disease control fencing to separate livestock from wildlife reservoirs. The objectives of this study were to evaluate differences in identifying high-risk areas for FMD using risk factor and expert opinion elicitation analysis. Differences in risk between FMD introduction and FMD spread within the FMD protection zone with vaccination (PZV) of South Africa (2007-2016) were also investigated. The study was conducted in the communal farming area of the FMD PZV, which is adjacent to wildlife reserves and characterised by individual faming units. Eleven risk factors that were considered important for FMD occurrence and spread were used to build a weighted linear combination (WLC) score based on risk factor data and expert opinion elicitation. A multivariable conditional logistic regression model was also used to calculate predicted probabilities of a FMD outbreak for all dip-tanks within the study area. Smoothed Bayesian kriged maps were generated for 11 individual risk factors, overall WLC scores for FMD occurrence and spread and for predicted probabilities of a FMD outbreak based on the conditional logistic regression model. Descriptively, vaccine matching was believed to have a great influence on both FMD occurrence and spread. Expert opinion suggested that FMD occurrence was influenced predominantly by proximity to game reserves and cattle density. Cattle populations and vaccination practices were considered most important for FMD spread. Highly effective cattle inspections were observed within areas that previously reported FMD outbreaks, indicating the importance of cattle inspection (surveillance) as a necessary element of FMD outbreak detection. The multivariable conditional logistic regression analysis, which was consistent with expert opinion elicitation; identified three factors including cattle population density (OR 3.87, 95% CI 1.47-10.21) and proximities to game reserve fences (OR 0.82, 95% CI 0.73-0.92) and rivers (OR 1.04, 95% CI 1.01-1.07) as significant factors for reported FMD outbreaks. Regaining and maintaining an FMD-free status without vaccination requires frequent monitoring of high-risk areas and designing targeted surveillance.

Toxoplasmosis epidemic in a population of urbanised allied rock-wallabies (Petrogale assimilis) on Magnetic Island (Yunbenun), North Queensland.

A mortality event involving 23 allied rock-wallabies (Petrogale assimilis) displaying neurological signs and sudden death occurred in late April to May 2021 in a suburban residential area directly adjacent to Magnetic Island National Park, on Magnetic Island (Yunbenun), North Queensland, Australia. Three allied rock-wallabies were submitted for necropsy, and in all three cases, the cause of death was disseminated toxoplasmosis. This mortality event was unusual because only a small, localised population of native wallabies inhabiting a periurban area on a tropical island in the Great Barrier Reef World Heritage Area were affected. A disease investigation determined the outbreak was likely linked to the presence of free-ranging feral and domesticated cats inhabiting the area. There were no significant deaths of other wallabies or wildlife in the same or other parts of Magnetic Island (Yunbenun) at the time of the outbreak. This is the first reported case of toxoplasmosis in allied rock-wallabies (Petrogale assimilis), and this investigation highlights the importance of protecting native wildlife species from an infectious and potentially fatal parasitic disease.

Comparison of ionised calcium measured using a portable analyser to a reference method in healthy dogs.

OBJECTIVES: To compare the ionised calcium measured on a portable analyser (iSTAT, Abbott) to a reference method. MATERIALS AND METHODS: Blood samples from 39 apparently healthy dogs were analysed in duplicate using a portable analyser and a reference method (Radiometer ABL800 FLEX). Bland-Altman plots and Passing-Bablok regression were used to assess constant and proportional bias between the two instruments. A within-assay percentage coefficient of variation and total error (TE) was calculated for both analysers. The reference interval was calculated for the portable analyser using the robust method with confidence interval bootstrapping. RESULTS: The Bland-Altman plot showed a -0.036 mmol/L difference between the two instruments (95% confidence limit -0.08 to 0.01 mmol/L; limits of agreement -0.07 to 0.006 mmol/L). Neither the Bland-Altman plot nor the Passing-Bablock regression (slope -0.03; 95% confidence interval -0.08 to 0.19 and intercept 1; 95% confidence interval 0.83 to 1.2) showed significant proportional bias. The coefficient of variation for the portable analyser was 1.08%, compared to 0.78% for the reference method with a total error of 3.5% for the portable analyser. The estimated population-based reference interval for ionised calcium using the portable analyser is 1.23 to 1.42 mmol/L. CLINICAL SIGNIFICANCE: For the healthy dogs in this study, compared to the reference method, the portable analyser showed no significant bias for measurement of ionised calcium. Further studies including hyper and hypocalcaemic dogs are required to determine clinical impact of the use of this analyser.

A review of pig and poultry diseases in the Eastern Cape Province of South Africa, 2000-2020.

ABSTRACT: The informal poultry and pig sector in the Eastern Cape Province (ECP) of South Africa is of significant socio-economic importance as it sustains livelihoods and ensures food security; yet little is known about the distribution and prevalence of infectious and zoonotic diseases in this region. This paper reviews data published for pig and poultry diseases in the province during the last 20 years (2000-2020). The review included relevant published papers identified by a computerised literature search from Web of Science; provincial animal health reports; the national database from the Department of Agriculture, Land Reform and Rural Development (DALRRD); animal health reports submitted by DALRRD to the World Organisation for Animal Health (OIE) via the World Animal Health Information Database (WAHID) interface and laboratory records. A publication was considered eligible if it included qualitative or quantitative information on any disease affecting pigs and poultry including zoonosis. The search retrieved 174 publications, of which 26 were relevant. The review found that Newcastle disease (ND), coccidiosis and fowl pox (FP) were the most reported avian diseases in the national database, whereas avian infectious bronchitis (AIB), ND and highly pathogenic avian influenza (HPAI) were the most reported diseases in the OIE database. Classical swine fever (CSF) was the most reported pig disease in both databases. The retrieved literature on pig and poultry diseases was scarce and no longer up to date, providing decision makers with little information. The review identified important zoonotic diseases that require further studies yet failed to find information on important neglected diseases like leptospirosis.

Using value chain and trade networks in the Eastern Cape Province of South Africa, as a basis for targeted rural chicken surveillance.

Despite the benefits of rural chickens in the Eastern Cape Province (ECP) of South Africa, this sector is still underdeveloped and poorly surveyed for poultry diseases. The lack of a sustainable poultry disease surveillance system coupled with communities and practices where the interactions between birds are high, emphasize the need for targeted surveillance of chicken diseases in the province. However, to set up such a system requires knowledge of the value chain and trade networks. Consequently, a survey, which involved a rural chicken value chain analysis that also included an assessment of trading practices to identify biosecurity hotspots and an identification of barriers to market entry for rural farmers was conducted. Secondly, a social network analysis of chicken movements in the province was carried out to identify trade hubs that could be targeted for disease surveillance based on their centrality within the network and their size and influence within their ego networks. Traders and their transport vehicles were identified as biosecurity hotspots that could be targeted for disease surveillance within the chain. Social network analysis identified three municipalities viz. Umzimvubu, King Sabata Dalindyebo (KSD) and Enoch Mgijima as trade hubs where interaction between rural chickens occurs and resources can be focused. The movement of spent hens from commercial operations that are transported over long distances and distributed in the rural areas and townships were a major risk for spread of poultry diseases. This is the first study to formally describe chicken trade networks within the province and the surrounding region. Its findings provide a model for cost effective targeted surveillance in the ECP and similar resource poor regions of the world. The study also provides insight into the profitability of rural chickens and a possible contribution to job creation and poverty alleviation once the barriers to market entry are lifted.

A study of rural chicken farmers, diseases and remedies in the Eastern Cape province of South Africa.

The source of emerging diseases and antimicrobial resistance is of increasing interest to epidemiologists. This paper looks at village chickens as such a source. In addition, infectious diseases constitute a major challenge to the growth and profitability of the rural poultry sector in Sub-Saharan Africa. A serological survey was conducted to estimate the apparent seroprevalence of selected chicken diseases in the Eastern Cape Province of South Africa alongside a sociological survey of poultry farmers and the remedies most commonly used to prevent diseases in their flocks. Sera collected from village chickens (n = 1007) in the province were screened for specific antibodies against Newcastle disease (ND), avian influenza (AI), avian infectious bronchitis (IB) and Mycoplasma gallisepticum (MG). The overall seroprevalence of ND, AI, IB and MG in the province was found to be 69.2 % (95 % CI 51.9-86.5%); 1.8 % (95 % CI 0.2-3.4%); 78.5 % (95 % CI 74.9-82%) and 55.8 % (95 % CI 41.3-70.3%) respectively with clustering found at the District level. Cross hemagglutination inhibition (HI) tests indicated that the chickens were exposed to the ND vaccine. AI ELISA-positive samples were tested using HIs against the H5, H6 and H7-subtypes, but only H6-specific antibodies were detected. Avian influenza strains shared the common ancestor responsible for the 2002 chicken outbreak in KwaZulu-Natal Province. The majority of chicken farmers were females and pensioners (69 % and 66.1 % respectively) and had a primary school education (47.1 %). Traditional remedies were commonly used by farmers (47.15 %) and among the remedies, Aloe plant (Aloe ferox Mill.) or ikhala (Xhosa) was the most commonly used product (28.23 %) for preventing and reducing mortalities among village chickens. The findings stress the importance of village chickens as a substitute for social welfare and highlight the exposure of village chickens to important chicken pathogens. The economic impact of these pathogens on the development of this sub-sector needs further investigation. Village chickens are a potential source of virulent Newcastle disease virus (NDV) because of the lack of vaccination and biosecurity. They may serve as amplification hosts which increases the probability that virulent NDV could spill over into commercial poultry flocks due to large amounts of circulating virus. The zoonotic threat of circulating H6N2 viruses raise concern due to their mutation and reassortment among chickens and a potential movement of infected birds within the province. Finally, the use of antibiotics by untrained chicken farmers constitute another major concern as it could serve as a source of antimicrobial resistance (AMR).

Analysing production and financial data from farmers can serve as a tool for identifying opportunities for enhancing extension delivery among the rural poultry sub-sector in Zambia.

There are limited data on production and financial performance of the rural poultry sector in developing countries like Zambia that could be used by extension services as a feedback loop to enhance service delivery in the sector. Thus, a study that used production and financial data obtained from poultry farmers of Eastern Zambia was conducted to describe the rural poultry sub-sector and conduct financial analysis. It compared the financial performance of indigenous chicken production to broiler and layer production. The aim of the study was to identify opportunities and knowledge gaps among poultry farmers that could be used to initiate and enhance a participatory extension approach and build capacity of farmers in the sector. Descriptive, spatial, gross margin and breakeven analysis was used to analyse data obtained from 459 rural poultry farmers and expert opinion from 5 local extension workers. Poultry ranked highest in terms of popularity and numbers when compared with other animals kept by respondents (median = 20). Most poultry were kept under free-range and brood an average of 3.1 clutches. Except for annual set up costs, some variable costs and household poultry consumption, the study could obtain data on most production costs and income generated from poultry farmers. Nevertheless, gross margin analysis conducted using costing data from poultry farmers and expert opinion of extension workers revealed that indigenous chicken enterprises had the highest gross margin percentage of 72% compared to commercial broilers and layers which had gross margin percentages of 53% and 56% respectively. Breakeven analysis revealed that indigenous chickens required the lowest number of products to be sold (27) to realise profit compared to broilers (1011) and layers (873). The study justifies investment into the rural poultry sub-sector and discusses the use of gross margin templates as a means of incentivising rural farmers to participate in extension programmes.

Seroprevalence and associated risk factors of mosquito-borne alphaviruses in horses in northern Queensland.

OBJECTIVE: To investigate the seroprevalence and associated risk factors of alphaviruses (Ross River virus (RRV), Barmah Forest virus (BFV) and Whataroa virus (WHAV)) in northern Queensland horses. METHODS: A cross-sectional study of alphavirus antibodies in horses (n = 287) from 147 properties in northern Queensland from September 2013 to June 2014 was conducted. Owners of sampled horses were interviewed on potential risk factors. Data were analysed for associations using multivariable logistic regression. RESULTS: Antibody titres for RRV were demonstrated in samples from 134 properties (91%; 95% confidence interval (CI) 87-96%); 22 properties (15%) had BFV reactors (95% CI 12-18%) and 2 properties (1.4%) had WHAV reactors (95% CI -0.5-3.2%). The highest seroprevalence of RRV was in the Townsville-Burdekin region (93%; 95% CI 90-96%) followed by the Mackay-Whitsunday (90%; 95% CI 88-98%) and Far North Coast-Tableland (82%; 95% CI 74-90%) regions. No association (P ≤ 0.05) could be shown between any of the viruses and age groups, sexes, annual average temperature, degree of rainfall or proximity to wet environments. An association with reported large numbers of mosquitoes was seen for RRV but not BFV. A significant association between properties in close proximity to poultry and pigs was shown for BFV. CONCLUSION: RRV is endemic within the horse population of northern Queensland, but horses exhibit few clinical signs and could play a role as amplifying hosts in the tropics. Exposure of horses to BFV is significant in northern Queensland and it should be considered a differential diagnosis for RRV. WHAV warrants further study.

Is syndromic data from rural poultry farmers a viable poultry disease reporting tool and means of identifying likely farmer responses to poultry disease incursion?

Syndromic surveillance is a well described tool used in developed countries for alerting authorities to livestock disease incursions. However, little work has been done to evaluate whether this could be a viable tool in countries where disease reporting infrastructure and resources is poor. Consequently, a syndrome-based questionnaire study in Eastern Zambia was designed to gather data on previous encounters farmers had with poultry diseases, as well as control measures they use to mitigate them. Descriptive statistics and logistic regression were used to analyse the data. Farmers reported an overall annual disease incidence in rural poultry for eastern Zambia of 31% (90% CI 29-32%). Occurrence of poultry disease in the last 12 months was associated with use of middlemen to purchase poultry products (p = 0.05, OR = 7.87), poultry products sold or given away from the farm (p = 0.01, OR = 1.92), farmers experiencing a period with more trade of poultry and its products (p = 0.04, OR = 1.70), presence of wild birds near the farm or village (p = 0.00, OR = 2.47) and poultry diseases being reported from neighbouring farms or villages (p = 0.00, OR = 3.12). The study also tentatively identified three poultry diseases (Newcastle Disease, Gumboro Disease and Fowl Pox) from the thirty-four disease syndromes provided by farmers. Farmers reported an incidence of 27% for Newcastle Disease in 2014. When compared with the state veterinary services data which reported Newcastle Disease incidence at 9% in 2014, it seems syndromic data obtained from farmers may be more sensitive in identifying disease incursion. Thirty-six remedies and strategies farmers use to treat and control these diseases were revealed. The main control strategy for identified diseases was vaccination and the main treatment was unspecified herbs, which warrants further investigation and presents an opportunity for further research in ethno-veterinary medicine. More still, this study identified chilli, Aloe Vera, garlic onion, moringa, and ash as traditional remedies that are commonly being used in Eastern Zambia, and which are also used to treat poultry diseases in Zimbabwe and Botswana. Only fourteen remedies described are conventionally accepted by veterinarians as remedies and disease control measures for poultry diseases. This study shows that syndromic data obtained from farmers is a useful disease reporting tool and could be used as an effective means of alerting authorities to disease incursion. In addition, it shows that these data may give a more accurate estimate of incidence for certain diseases than current surveillance methods and could be useful in assessing significant risk factors associated with disease occurrence.

Tracing the origins of genotype VIIh Newcastle disease in southern Africa.

It is widely accepted that Newcastle disease is endemic in most African countries, but little attention has been afforded to establishing the sources and frequency of the introductions of exotic strains. Newcastle disease outbreaks have a high cost in Africa, particularly on rural livelihoods. Genotype VIIh emerged in South-East Asia and has since caused serious outbreaks in poultry in Malaysia, Indonesia, southern China, Vietnam and Cambodia. Genotype VIIh reached the African continent in 2011, with the first outbreaks reported in Mozambique. Here, we used a combination of phylogenetic evidence, molecular dating and epidemiological reports to trace the origins and spread of subgenotype VIIh Newcastle disease in southern Africa. We determined that the infection spread northwards through Mozambique, and then into the poultry of the north-eastern provinces of Zimbabwe. From Mozambique, it also reached neighbouring Malawi and Zambia. In Zimbabwe, the disease spread southward towards South Africa and Botswana, causing outbreaks in backyard chickens in early-to-mid 2013. In August 2013, the disease entered South Africa's large commercial industry, and the entire country was infected within a year, likely through fomites and the movements of cull chickens. Illegal poultry trading or infected waste from ships and not wild migratory birds was the likely source of the introduction to Mozambique in 2011.

Dairy farm demographics and management factors that played a role in the re-emergence of brucellosis on dairy cattle farms in Fiji.

Little is published on risk factors associated with bovine brucellosis in Pacific island communities. The 2009 re-emergence of bovine brucellosis in Fiji enabled us to do an interview-based questionnaire survey of 81 farms in the Wainivesi locality of the Tailevu province on the main island of Fiji to investigate what risk factors could have played a role in the re-emergence of the disease. The survey was conducted on 68 farms that had no positive cases of bovine brucellosis and on 13 farms in the same area where cattle had returned a positive result to the Brucella Rose Bengal test. Descriptive statistical methods were used to describe the demographic data while univariate analysis and multivariate logistic regression were used to evaluate the association between the selected risk factors and the presence of brucellosis on the farms at the time of the outbreak. The demographics of Fijian dairy farms are presented in the article and the biosecurity implications of those farming systems are discussed. Two risk factors were strongly associated with farms having brucellosis, and these were history of reactor cattle to brucellosis and or bovine tuberculosis on the farm (OR = 29, P ≤ 0.01) and farms that practised sharing of water sources for cattle within and with outside farms (OR = 39, P ≤ 0.01). Possible reasons why these were risk factors are also discussed. The potential risks for human health was also high as the use of personal protective equipment was low (15%). A high proportion of farmers (62%) could not recognise brucellosis thus contributing to the low frequency of disease reports (44%) made. The article also highlights other important risk factors which could be attributed to farming practices in the region and which could contribute to public health risks and the re-emergence of diseases.

A Survey of Zoonotic Pathogens Carried by Non-Indigenous Rodents at the Interface of the Wet Tropics of North Queensland, Australia.

In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in Northern Queensland, Australia. Genotyping of bacterial isolates in 2008 determined that they were a novel Brucella species. This study attempted to reisolate this species of Brucella from rodents living in the boundary area adjacent to WNP and to establish which endo- and ecto-parasites and bacterial agents were being carried by non-indigenous rodents at this interface. Seventy non-indigenous rodents were trapped [Mus musculus (52), Rattus rattus (17) and Rattus norvegicus (1)], euthanized and sampled on four properties adjacent to the WNP in July 2012. Organ pools were screened by culture for Salmonella, Leptospira and Brucella species, real-time PCR for Coxiella burnetii and conventional PCR for Leptospira. Collected ecto- and endo-parasites were identified using morphological criteria. The percentage of rodents carrying pathogens were Leptospira (40%), Salmonella choleraesuis ssp. arizonae (14.29%), ectoparasites (21.42%) and endoparasites (87%). Brucella and C. burnetii were not identified, and it was concluded that their prevalences were below 12%. Two rodent-specific helminthic species, namely Syphacia obvelata (2.86%) and Nippostrongylus brasiliensis (85.71%), were identified. The most prevalent ectoparasites belonged to Laelaps spp. (41.17%) followed by Polyplax spp. (23.53%), Hoplopleura spp. (17.65%), Ixodes holocyclus (17.64%) and Stephanocircus harrisoni (5.88%), respectively. These ectoparasites, except S. harrisoni, are known to transmit zoonotic pathogens such as Rickettsia spp. from rat to rat and could be transmitted to humans by other arthropods that bite humans. The high prevalence of pathogenic Leptospira species is of significant public health concern. This is the first known study of zoonotic agents carried by non-indigenous rodents living in the Australian wet-tropical forest interface.

Understanding Pig and Poultry Trade Networks and Farming Practices Within the Pacific Islands as a Basis for Surveillance.

Pacific Island countries have large pig and poultry populations. Yet little is known about patterns of contact between animals and how this influences disease spread in these islands. The objectives of this study were to examine farmer practices and the movements of pig and poultry within the Pacific Islands using questionnaires and social network analysis (SNA) tools to understand disease spread in the region. Questionnaire-based surveys were conducted in Fiji, Papua New Guinea (PNG), Solomon Islands and Vanuatu with interviews of 310 pig farmers and 491 poultry farmers. Pacific Island farmers were found to have few animals (median = 7 pigs/farm, IQR 4-12), (median = 50 chicken/farm, IQR 23-52), (median = 10 ducks/farm, IQR 4-25), (median = 12 Muscovy ducks/farm, IQR 7-28) and a diversified number of species. A large proportion of farmers (44.6-61.3%) do not implement any preventive or control measures, yet the majority (80.6-88%) did not experience any animal diseases over the past 12 months. Most farmers never ask for veterinary care, never engage in laboratory testing and do not report when their animals show clinical signs. Many pig farmers (31.8%) trade within their communities only and sell (24.5%) directly to consumers which reduces the risk of diseases spreading. Our results show an association between farmers that report having had disease on their farm in the past 12 months and movements of animals on and off their farms. The capitals of the studied provinces in PNG, Vanuatu and Solomon Islands were identified as the most connected nodes of both pig and poultry trade, while Fiji networks appeared much less connected. Our study found that farmer practices increased the risk of disease spread, but this was currently limited by trading practices. The SNA results serve as a basis for more targeted disease surveillance and better use of available resources for disease prevention and control.

A study of leptospirosis in South African horses and associated risk factors.

Most leptospiral infections in horses are asymptomatic; however, acute disease manifestations as well as reproductive failure and recurrent uveitis have been reported. In South Africa, the epidemiology of the disease in horses is not well documented. A serosurvey to determine what serovars were present in horses from Gauteng, KwaZulu-Natal and Western Cape Provinces and to get an estimate of the seroprevalence of leptospirosis was carried out from January 2013 until April 2014 with the assistance of four large equine hospitals located in these provinces. Furthermore, associations between potential risk factors and both seropositive horses to the predominant serovar Bratislava and to Leptospira spp. were statistically evaluated using univariate analysis and multivariable logistic regression models. A total of 663 horse sera were collected and tested against a panel of 24 leptospiral serovars using the microscopic agglutination test. The most predominant serovars in Gauteng were Bratislava [32%, 95% CI: 29-35%]; Djasiman [10.4%, 95% CI: 8-12%] and Arborea [8.9%, 95% CI: 7-11%], in the Western Cape Province, Bratislava [27.35%, 95% CI: 23-32]; Djasiman [15.4%, 95% CI: 12-19%] and Arborea [14.5%, 95% CI: 11-18%] and in KwaZulu-Natal, Bratislava [39.4%, 95% CI: 34-44%]; Arborea [9.6%, 95% CI: 7-13%]; and Tarassovi [7.7%, 95% CI: 5-10%] respectively. Twenty one serovars representing 17 serogroups were detected with serovar Bratislava being the most serodominant. The apparent prevalence to one or more serovars of Leptospira spp. at a serum dilution of 1:100 in Gauteng, KwaZulu-Natal and Western Cape Provinces were 49%; 37% and 32% respectively. The true prevalence was calculated for each province taking into account the clustering effect during the sampling and was found to be between 24 and 74% in Gauteng; 26-39% in the Western Cape and 20-54% in KwaZulu-Natal. Nooitgedacht (South African horse breed) horses were found to be at greater risk of being seropositive to both serovar Bratislava (OR=5.08) and Leptospira spp. (OR=6.3). Similarly, horses residing on properties with forestry in the vicinity were found to be at greater risk of being seropositive to both serovar Bratislava (OR=9.3) and Leptospira spp. (OR=5.2). This study has shown that a high proportion of horses in South Africa are exposed to a wide range of serovars, inferring a complex epidemiology. It also describes for the first time new serovars of Leptospira in South African horses that have not previously been reported.

A retrospective study and predictive modelling of Newcastle Disease trends among rural poultry of eastern Zambia.

Newcastle Disease (ND) is a highly infectious disease of poultry that seriously impacts on food security and livelihoods of livestock farmers and communities in tropical regions of the world. ND is a constant problem in the eastern province of Zambia which has more than 740 000 rural poultry. Very few studies give a situational analysis of the disease that can be used for disease control planning in the region. With this background in mind, a retrospective epidemiological study was conducted using Newcastle Disease data submitted to the eastern province headquarters for the period from 1989 to 2014. The study found that Newcastle Disease cases in eastern Zambia followed a seasonal and cyclic pattern with peaks in the hot dry season (Overall Seasonal Index 1.1) as well as cycles every three years with an estimated provincial incidence range of 0.16 to 1.7% per year. Annual trends were compared with major intervention policies implemented by the Zambian government, which often received donor support from the international community during the study period. Aid delivered through government programmes appeared to have no major impact on ND trends between 1989 and 2014 and reasons for this are discussed. There were apparent spatial shifts in districts with outbreaks over time which could be as a result of veterinary interventions chasing outbreaks rather than implementing uniform control. Data was also fitted to a predictive time series model for ND which could be used to plan for future ND control. Time series modelling showed an increasing trend in ND annual incidence over 25 years if existing interventions continue. A different approach to controlling the disease is needed if this trend is to be halted. Conversely, the positive trend may be a function of improved reporting by farmers as a result of more awareness of the disease.

Effect of hormonal synchronisation and/or short-term supplementation with maize on follicular dynamics and hormone profiles in goats during the non-breeding season.

This study aimed to evaluate the reproductive response of anoestrous goats that were either hormonally treated and/or supplemented with maize for 9days to determine which treatment combination was the most effective in enhancing follicular development and ovulation rate, and whether these responses were associated with increases in metabolic hormones. The experiment was carried out using 28 does, using a 2×2 factorial design with seven does in each group to test the effect of synchronisation of oestrus, supplementation with maize and their interactions. Synchronisation of oestrous cycles (P<0.001) but not supplementation with maize or the interaction between the two (P>0.05) increased the number of codominant follicles, the diameter of the largest follicle on Day 9 and growth rate of follicles during the period of supplementation. Compared with non-supplemented animals, supplementation with maize increased the total number of follicles observed between Days 7 and 9 (P=0.039). In addition, nutritional supplementation with maize in combination with synchronisation of oestrus increased the ovulation rate by 43% (P=0.074). Interactions between time and supplementation with maize showed that plasma concentrations of insulin, leptin and IGF-1 were greater in does supplemented with maize compared with non-supplemented does (P<0.001). The findings show that hormonal synchronisation had the most influence on modifying follicular development and ovulation in anoestrous goats. Supplementation with maize increased the concentrations of insulin, leptin and IGF-1, which could potentially modify the sensitivity of follicles to gonadotrophins and reduce rates of atresia.

Circulating serovars of Leptospira in cart horses of central and southern Ethiopia and associated risk factors.

Little work has been done on diseases of horses in Ethiopia or tropical regions of the world. Yet, Ethiopia has the largest horse population in Africa and their horses play a pivotal role in their economy as traction animals. A serological and questionnaire survey was therefore conducted to determine the circulating serovars of Leptospira and their association with potential risk factors in the cart horse population of Central and Southern Ethiopia. A total of 184 out of 418 cart horses from 13 districts had antibody titres of 1:100 or greater to at least one of 16 serovars of Leptospira species in Central and Southern Ethiopian horses. A significantly higher seropositivity (62.1%) was noted in horses from the highland agroecology followed by midland (44.4%) and lowland (39.8%). Serovar Bratislava (34.5%) was the predominant serovar followed by serovars Djasiman (9.8%), Topaz (5.98%) and Pomona (5.3%). Age and location proved to be associated with seropositive horses with older horses being more commonly affected and the districts of Ziway (Batu) (Apparent Prevalence (AP)=65.5%), Shashemene (AP=48.3%) and Sebeta (AP=41.4%) having the highest prevalence. Multivariable logistic regression found risk factors significantly associated with Leptospira seropositive horses were drinking river water (OR=2.8) and horses 7-12 years old (OR=5) and risk factors specifically associated with serovar Bratislava seropositive horses were drinking river water (OR=2.5), horses ≥13 years (OR=3.5) and the presence of dogs in adjacent neighbouring properties (OR=0.3). Dogs had a protective effect against seropositivity to serovars Bratislava and Djasiman, which may be due to their ability to control rodents. The high seroprevalence confirm that leptospirosis is endemic among horses of Central and Southern Ethiopia. The predominance of serovar Bratislava supports the idea that serovar Bratislava may be adapted to and maintained by the horse population of Central and Southern Ethiopia. This study emphasizes the need for further countrywide serological surveys and isolation of circulating leptospires in animals and humans in order to understand the role of horses in the epidemiology of this disease.

A field investigation into a suspected outbreak of pyrrolizidine alkaloid toxicosis in horses in western Queensland.

A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical-pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure period. All five affected properties experienced a very dry spring and early summer preceded by a large summer wet season. The outbreak was characterised as a point epidemic with a sudden peak of deaths in March followed by mortalities steadily declining until the end of June. The estimated morbidity (serum IGG>50IU/L) rate was 76%. Average crude mortality was 27% but higher in young horses (67%) and brood mares (44%). Logistic regression analysis showed that young horses and brood mares and those grazing denuded pastures in December were most strongly associated with dying whereas those fed hay and/or grain based supplements were less likely to die. This is the first detailed study of an outbreak of PA toxicosis in central western Queensland and the first to provide evidence that environmental determinants were associated with mortality, that the critical exposure period was towards the end of the dry season, that supplementary feeding is protective and that denuded pastures and the horses physiological protein requirement are risk factors.

Risk factors for porcine reproductive and respiratory syndrome outbreaks in Vietnamese small stock farms.

AIM: To examine risk factors that could have played a role in the 2010 porcine reproductive and respiratory syndrome (PRRS) outbreak in Yenhung district, Quangninh province, North-Vietnam, with the purpose of establishing why existing control measures implemented after previous outbreaks had failed to prevent further outbreaks. METHODS: A case-control study was carried out in Yenhung district. Data were obtained by an interview-based questionnaire survey. The sampling unit was households, which equated to small-scale pig farms. A total of 150 case and 150 control households were selected at communes affected by the 2010 PRRS epidemic during April to June. Risk factors were analysed using binary logistic regression and unconditional multiple logistic regression. RESULTS: Households infected with PRRS were significantly associated with multiple variables belonging to three main groups: (1) location of the farms: i.e. farms positioned <1,000 m from a pig abattoir or within 500 m of local markets or 100 m of main roads; (2) farm management: i.e. where there was non-application of weekly farm disinfection, feeding uncooked swill, new introduction of purchased pigs without isolation, or usage of water from irrigation systems for raising pigs; (3) people and animal contact: i.e. where households kept animals with either no confinement or partial confinement, had visits by family members to other affected farms or had frequent visits by neighbours. The use of water from irrigation systems was found to be the risk factor most strongly associated with infected households in the 2010 outbreak (OR=22; 95% CI=12-42). CONCLUSIONS: The results show that the epidemiology of PRRS in Quangninh province was linked to sociological and cultural practices, and that effective PRRS control needs an integrated approach coupled with behavioural changes in the pig raising practices of the general public. Failure to recognise this could explain why further outbreaks have occurred.

Equine leptospirosis in tropical Northern Queensland.

OBJECTIVE: Determine leptospiral serodiversity, serodominant serovars and prevalence in the horse population of Northern Queensland (NQ), Australia, with special focus on the Atherton Tableland and Townsville-Burdekin regions. DESIGN: Cross-sectional survey. METHODS: Serum samples from 429 horses originating from 172 horse-owning properties in NQ were collected at regional horse shows and veterinary clinics. Samples were analysed using a microscopic agglutination test. Owners were interviewed on potential risk factors associated with leptospirosis. RESULTS: Of the 172 properties that submitted samples, horses from 60 properties (35%, 95% confidence interval (CI) 31-39%) in NQ showed evidence of exposure to one or more serovars of Leptospira at a serum dilution of 1 : 100. The proportion of seropositive properties in the Atherton Tableland and Townsville-Burdekin regions was 25% (95% CI 17-33%) and 36% (95% CI 30-43%), respectively. In total, 81 horses had titres to a single serovar and the remained had titres to two or more serovars. Although 20 serovars representing 17 serogroups were detected, serovar Arborea was serodominant and detected in horses from 29 properties. Geldings were more at risk (odds ratio 3.3) of being seropositive to serovar Arborea. The detection of serovar Arborea-seropositive horses was strongly associated (P < 0.05) with the average annual rainfall each property received and the presence of pigs and sugarcane fields in the vicinity. CONCLUSION: Serological evidence of leptospirosis in horses in NQ indicates that prevalence is high and horses have been exposed to a wide range of serovars.