Sero-epidemiology of foot-and-mouth disease in some border states of Nigeria

A serological survey was conducted between 2009 and 2011 in six Border States and two other states that lie on the major cattle trek routes in Nigeria with the objective of determining the seroprevalence of foot and mouth disease (FMD) in cattle and demonstrate the evidence of antibodies in sheep, goats and pigs. Four hundred and forty-eight (448) sera were screened for FMD antibodies using the Enzyme-linked immunosorbent assay (ELISA) including samples collected during suspected field outbreaks. Statistics was conducted by using the modified Wald method and two-by-two contingency table. Higher seroprevalence was recorded in cattle samples from Yobe State (82%), followed by those from Plateau (80%), Ogun (77.77%), Taraba (73.50%), Adamawa (68%), Borno (67%), Sokoto (63%) cattle and Bauchi (27.84%), is only in sheep and goat. None of the pig sera obtained from Kaduna was positive. There is no difference in seropositivity between cattle sampled at the border and those from the trek routes. The result confirmed that FMD is still an important cattle disease in Nigeria since the diagnostic procedure employed in this analysis only detect positive serum in FMD infected animals and no history of vaccination was declared for any of the surveyed animals. Based on these results, it will be important to determine the recently circulating virus strains and factors responsible for the widespread seropositivity in order to design appropriate control strategies to limit the effect of FMD particularly on the Nigerian cattle.http://www.academicjournals.org/AJMRab201

Impact of foot-and-mouth-disease on goat behaviour after experimental infection with serotype SAT1 virus

Infectious diseases and parasitic infestations can cause a set of non-specific clinical signs, such as increased body temperature and resting, and a decrease in food intake. These physiological and behavioural changes have an adaptive function facilitating defences against the pathogen and to support immune functions. These so-called’ sickness behaviours’ can also be used as an early detection tool for disease. Foot-and-mouth disease (FMD) still causes great economic losses in endemic countries, especially to smallholder farmers. The aim of this study was to determine if behavioural changes in goats can be used as an early indicator of FMD virus (FMDV) infection. The efficacy of a Southern African Territories (SAT) FMD vaccine was studied on forty South African indigenous goats. Changes in daily activities (resting, feeding, walking), as well as social behaviours (social resting, social feeding, dominance behaviours) were recorded and then compared over time and between clinically affected and unaffected goats. Pedometers were used to estimate average daily steps and to compare between groups of study animals. Eleven goats developed clinical signs of FMD, as well as non-FMD related sicknesses during the course of the study. Overall walking and resting behaviours were not significantly affected by the presence of FMD related clinical signs (p > 0.05). However, during the time of FMDV infection, social resting increased significantly (p < 0.001). Although goats developed FMD lesions on lips and tongues, percentage of time feeding was not affected (p = 0.762), suggesting that the study goats did not perceive the oral lesions as an important disturbance. Similarly, the number of steps did not consistently decrease in the presence of FMD-associated foot lesions. When affected by non-FMD related sicknesses, animals did not have an overall reduction in the time spent feeding (p = 0.867). However, goats affected with non-FMD conditions reduced the amount of social feeding (p = 0.002), potentially avoiding energetically costly competition at the feeding points. Overall, goats affected with FMD did not show more sickness behaviour, suggesting that FMDV infection in goats might not lead to obvious and therefore, easily detectable behavioural changes. This might have implications for farmers and animal health personnel, as individual goats infected with FMDV might be undetected within a flock due to the absence of obvious sickness behaviours, and the virus can therefore be spread more easily between herds through animal movements.The National Research Foundation (NRF), South Africa and the Peace Parks Foundation.http://www.elsevier.com/locate/prevetmedhj2021Mammal Research InstituteProduction Animal Studie

Preliminary validation of a single-spot version of a solid-phase competition ELISA for the detection of southern African territories foot-and-mouth disease serotype exposure in goats

Appendix A. Supporting informationThe objective of this study was to perform a preliminary validation of a solid-phase competition ELISA (SPCE) in goats exposed to foot-and-mouth disease virus (FMDV) southern African territories (SAT) serotypes through vaccination or experimental infection. Thirty-nine goats were vaccinated with a FMDV vaccine and 37 subsequently challenged with a SAT1 virus serotype. Blood was collected every 7 days until termination at 14 days post-challenge. Single-spot SAT1 virus serotype SPCE (ss-SPCE) was performed in duplicate at two time points and a half-titration version was performed after a variable time of long-term storage. Coefficient of variation (CV) was calculated and accuracy of the ss-SPCE was estimated relative to a half-titration SPCE log10 titer of 1.6 using mixed-effect logistic regression. Additionally, sensitivity and specificity were estimated based on serological results 14-days post-challenge and at study enrolment, respectively. Three hundred and forty-two serum samples were tested in duplicate on two non-consecutive days. The median (interquartile range (IQR)) CV for the ss-SPCE for SAT1 was 2.1% (0.5, 14.3%) and 2.5% (0.6, 12.8%) for the two testing days, respectively. Median (IQR) interassay (different day) CV was 10.6% (2.5, 42.5%). Specificity and sensitivity of the ss-SPCE relative to the log10 titer using a 70% percentage inhibition positive threshold were 83.4% (95% confidence interval, 77.7–87.9) and 95.8% (90.7–98.2), respectively. Specificity was estimated as 100% (92.6, 100) and sensitivity as 97.3% (87.4, 99.9) when only considering serum tested at the beginning and end of the study, respectively. The SAT1 ss-SPCE is repeatable and accurate for determining FMDV serological status in goats.The National Research Foundation (NRF), South Africa, the Peace Parks Foundation, and MSc studies supported by South African Agricultural Sector Education and Training Authority (AgriSETA) awarded to the Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria.https://www.elsevier.com/locate/smallrumresam2024Production Animal StudiesVeterinary Tropical DiseasesNon

Cost implications of African swine fever in smallholder farrow-to-finish units : economic benefits of disease prevention through biosecurity

African swine fever remains the greatest limitation to the development of the pig industry in Africa, and parts of Asia and Europe. It is especially important in West and Central African countries where the disease has become endemic. Biosecurity is the implementation of a set of measures that reduce the risk of infection through segregation, cleaning and disinfection. Using a 122-sow piggery unit, a financial model and costing were used to estimate the economic benefits of effective biosecurity against African swine fever. The outcomes suggest that pig production is a profitable venture that can generate a profit of approximately US$109 637.40 per annum and that an outbreak of African swine fever (ASF) has the potential to cause losses of up to US$910 836.70 in a single year. The implementation of biosecurity and its effective monitoring can prevent losses owing to ASF and is calculated to give a benefit-cost ratio of 29. A full implementation of biosecurity will result in a 9.70% reduction in total annual profit, but is justified in view of the substantial costs incurred in the event of an ASF outbreak. Biosecurity implementation is robust and capable of withstanding changes in input costs including moderate feed price increases, higher management costs and marginal reductions in total outputs. It is concluded that biosecurity is a key to successful pig production in an endemic situation.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-1682ab201

Optimization of a foot-and-mouth disease virus Southern African Territories–specific solid-phase competitive ELISA for small ruminant serum samples

We optimized and verified a single-spot solid-phase competitive ELISA (ss-SPCE) to detect antibodies against structural proteins of Southern African Territories (SAT) serotypes of foot-and-mouth disease virus (FMDV) in small ruminants. Sera from goats vaccinated and experimentally challenged with a SAT1 FMDV pool were tested in duplicate at 4 dilutions (1:10, 1:15, 1:22.5, 1:33.8) to optimize the assay. To assess the performance of the assay in naturally infected animals, we evaluated 316 goat and sheep field sera collected during active SAT2 outbreaks. Relative to results of the virus neutralization test, the optimal serum dilution and cutoff percentage inhibition (PI) were 1:15 and 50%, respectively. At these values, the Spearman rank correlation coefficient was 0.85 (p < 0.001), and the sensitivity and specificity (95% CI) were 80.3% (72.6, 87.2) and 91.1% (84.1, 95.9), respectively. Relative to the liquid-phase blocking ELISA and the nonstructural protein ELISA, the ss-SPCE exhibited divergent performance characteristics between the goat and sheep field sera. Repeatability was better for goats, but the correlation and agreement among all 3 assays were better for the sheep sera. The prevalence of SAT2 FMDV infection in the sampled sheep was 23.6%; sampled goats were seemingly FMDV-free. The ss-SPCE is an appropriate FMDV detection tool to investigate the role of small ruminants in the epidemiology of FMD in Africa.The Red Meat Research Development (RMRD) of South Africa.https://journals.sagepub.com/home/VDIhj2024Production Animal StudiesSDG-03:Good heatlh and well-bein

Efficacy of a foot-and-mouth disease vaccine against a heterologous SAT1 virus challenge in goats

Please read abstract in the article.The National Research Foundation (NRF), South Africa and the Peace Parks Foundation.http://www.elsevier.com/locate/vaccinehj2021Production Animal Studie

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.The National Research Foundation of South Africa.https://www.elsevier.com/locate/prevetmedhj2024Production Animal StudiesSDG-03:Good heatlh and well-beingSDG-15:Life on lan

Improving foot-and-mouth disease control through the evaluation of goat movement patterns within the FMD protection zone of South Africa

Foot-and-mouth disease (FMD) is a transboundary animal disease that has a major impact on livestock production, regional and international trade and livelihoods of smallholder farmers in endemic settings. Many livestock diseases are transmitted through direct contact between animals, and thus between herds and flocks through animal movements. In this study, we described the pattern of goat movements among smallholder farmers within a communal farming area in South Africa. A cross-sectional survey using a semi-structured questionnaire was administered to 116 respondents, and separate 13 focus group discussions employing participatory mapping and semi-structured interviews were conducted among smallholder farmers. Overall, 22% (95% confidence interval [CI]: 16 – 31) of questionnaire respondents indicated moving new animals into their holdings during the previous 12 months while 56% (95% CI: 47 – 65) reported moving animals out of the holdings during the same timeframe. A total of 134 participants attended the focus group discussions with 68% (91/134) being male and 32% (43/134) female. Data from the study reported 37 nodes and 78 ties with an overall network density of 0.059 (SD 0.2) across the study area. Four locations within the (former) FMD-free zone of the country had connections with movement of goats from the study area. Furthermore, 60% (95% CI: 51 – 69) of farmers were ignorant of the need to obtain official veterinary movement permits for goats. These animal movements put the country at risk of future FMD outbreaks within the free zone. We recommend that the relevant authorities implement risk-based control measures to prevent the spread of infectious diseases.http://www.elsevier.com/locate/smallrumres2022-06-05hj2021Mammal Research InstituteProduction Animal Studie

Risk factors for farm-level African swine fever infection in major pig-producing areas in Nigeria, 1997-2011

African swine fever (ASF) is an economically devastating disease for the pig industry, especially in Africa. Identifying what supports infection on pig farms in this region remains the key component in developing a risk-based approach to understanding the epidemiology of ASF and controlling the disease. Nigeria was used for this matched case-control study, because there is perpetual infection in some areas, while contiguous areas are intermittently infected. Risk factors and biosecurity practices in pig farms were evaluated in association with ASF infection. Subsets of farms located in high-density pig population areas and high-risk areas for ASF infection were randomly selected for analysis. Most plausible risk factor variables from the univariable analysis included in the multivariable analysis include: owner of farm had regular contact with infected farms and other farmers, untested pigs were routinely purchased into the farm in the course of outbreaks, there was an infected neighbourhood, other livestock were kept alongside pigs, there was a presence of an abattoir/slaughter slab in pig communities, wild birds had free access to pig pens, tools and implements were routinely shared by pig farmers, there was free access to feed stores by rats, and feed were purchased from a commercial source Only the presence of an abattoir in a pig farming community (OR = 8.20; CI95% = 2.73; 24.63; P < 0.001) and the presence of an infected pig farm in the neighbourhood (OR = 3.26; CI95% = 1.20; 8.83; P = 0.02) were significant. There was a marginally significant negative association (protective) between risk of ASF infection and sharing farm tools and equipment (OR = 0.35; CI95% = 0.12; 1.01; P = 0.05). Of the 28 biosecurity measures evaluated, food and water control (OR = 0.14; CI95% = 0.04, 0.46; P < 0.001), separation/isolation of sick pigs (OR = 0.14; CI95% = 0.04, 0.53; P = 0.004) and washing and disinfection of farm equipment and tools (OR = 0.27; CI95% = 0.10, 0.78; P = 0.02) were negatively associated (protective) with ASF infection. Consultation and visits by veterinarian/paraveterinarians when animals were sick (OR = 8.11; CI95% = 2.13, 30.90; P = 0.002), and pest and rodent control were positively associated with ASF infection of Nigerian farms (OR = 4.94; CI95% = 1.84, 13.29; P = 0.002). The presentation of sick and unthrifty pigs for slaughter at abattoirs, farmers’ inadvertent role, an infected neighbourhood, a pig to pig contact, rodents and wild birds may contribute to infections of farms, whereas washing, disinfection of tools, food and water control, and separation of sick pigs reduces the likelihood of infections. Underlying reasons for these observations and strategies for control are discussed.http://www.elsevier.com/locate/prevetmedab201

Foot-and-mouth disease virus strains and examination of exposure factors associated with seropositivity of cattle herds in Nigeria during 2007–2009

New outbreaks of foot-and-mouth disease (FMD) occurred in cattle herds in Nigeria during 2007-2009. The objectives of the study reported here were (i) to identify current FMD virus strains circulating in cattle herds and (ii) to identify exposure factors associated with a seropositive diagnosis of FMD in cattle herds. This study provides evidence that FMD virus serotypes O, A and SAT-2 were co-circulating in cattle herds in Nigeria during 2007-2009. Cattle herds in a neighborhood affected with FMD had higher odds of being classified as seropositive to FMD, compared to herds that were in a neighborhood not affected with FMD (OR = 16.27; 95% CI = 3.61, 18.74; P < 0.01). Cattle herds that share water points along the trek routes with other cattle herds had higher odds of being classified as seropositive to FMD (adjusted OR = 4.15; 95% CI = 0.92, 18.74; P < 0.06). Results from this study can be used by veterinary services in Nigeria and neighboring countries to evaluate current or future FMD control and eradication programs.http://www.elsevier.com/locate/prevetme