Comparative Evaluation of Three Commercial ELISA Kits for Detection of Antibodies to a Nonstructural Protein of Foot-and-Mouth Disease Virus

Summary Foot‐and‐mouth disease (FMD) inflicts severe economic losses within infected countries and is arguably the most important trade‐restricting livestock disease in the world. In southern Africa, infected African buffaloes (Syncerus caffer) are the major reservoir of the South African Territories (SAT) types of the virus. With the progressive expansion of transfrontier conservation areas (TFCAs), the risk of FMD outbreaks is expected to increase due to a higher probability of buffalo/livestock contacts. To investigate the dynamics of FMD within and around the Great Limpopo TFCA (GLTFCA), 5 herds of buffaloes were sampled in June 2010 to characterize circulating viruses in South Africa and Zimbabwe. Three SAT‐2 and three SAT‐3 viral strains were isolated in both countries, including one that was genetically linked with a recent SAT‐2 outbreak in Mozambique in 2011. In addition, two groups of unvaccinated cattle (n = 192) were serologically monitored for 1 year at the wildlife/livestock interface of Gonarezhou National Park (GNP) in Zimbabwe between April 2009 and January 2010, using the liquid‐phase blocking ELISA (LPBE) and a test for antibodies directed against non‐structural proteins (NSP). Neither clinical signs nor vaccination of cattle were reported during the study, yet a high proportion of the monitored cattle showed antibody responses against SAT‐3 and SAT‐1. Antibodies against NSP were also detected in 10% of the monitored cattle. The results of this study suggest that cattle grazing in areas adjacent to the GLTFCA can be infected by buffalo or other infected livestock and that cattle trade movements can act as efficient disseminators of FMD viruses to areas several hundred kilometres from the virus source. Current methods of surveillance of FMD at the GLTFCA interface seem insufficient to control for FMD emergence and dissemination and require urgent reassessment and regional coordination.

Section: Discussionmentioning

confidence: 98%

Characteristics of Foot-and-Mouth Disease Viral Strains Circulating at the Wildlife/livestock Interface of the Great Limpopo Transfrontier Conservation Area

Jori

Caron

Thompson

et al. 2014

“…Serological testing was performed using a commercial non‐structural protein (NSP) FMDV ELISA test kit (PrioCheck FMDV by Prionics) using a cut point of 50% inhibition as specified by the manufacturer (Sørensen et al, ). The PrioCheck FMD ELISA has published specificity in cattle of 95%–99% depending on the vaccination status of the cattle in question (Fukai, Morioka, Onozato, Yoshida, & Sakamoto, ; Sørensen et al, ) The sensitivity of this test in experimentally infected animals nears 100% (Brocchi et al, ).…”

Section: Methodsmentioning

confidence: 99%

Evaluating the utility of national‐scale data to estimate the local risk of foot‐and‐mouth disease in endemic regions

Andel

Zaari

Phiri

et al. 2019

Knowledge of the distribution of foot‐and‐mouth disease (FMD) is required if control programmes are to be successful. However, data on the seroprevalence and incidence of affected villages in developing countries with endemic disease are scarce. This is partly due to resource constraints as well as the logistical challenges of conducting intensive surveys and diagnostic testing in remote locations. In this study, we evaluated the performance of low resolution national‐scale data against high resolution local survey data to predict the FMD serological status of 168 villages in the Mandalay and Sagaing Regions of central Myanmar using both logistic regression and random forest modelling approaches. Blood samples for ELISA testing were collected from approximately 30 cattle per village in both the 6 to 18 month age range and in the over 18 month age range to distinguish between recent and historical exposure, respectively. The results of the animal level tests were aggregated to the village level to provide the outcome of interest (village positive or not positive for FMD), and three explanatory data sets were constructed: using only nationally available data, using only data collected by survey and using the combined survey and nationally available data. The true seroprevalence of FMD at the village level was 61% when only young animals were included, but increased to 87% when all animals were included. The best performing model was a logistic regression model using the combined national and survey data to predict recent infection in villages. However, this still incorrectly classified 40% of villages, which suggests that using national‐level data were not reliable enough for extrapolating seroprevalence in regions where conducting detailed surveys is impractical. Other methods for collected data on FMD such as the use of local reporting should be explored.

“…Serological testing was performed using a commercial non-structural protein (NSP) ELISA test kit (PrioCheck FMDV by Prionics) using a cut point of 50% inhibition as specified by the manufacturer (Sørensen et al, 1998). The PrioCheck FMD ELISA has published specificity in cattle of 95 to 99% depending on the vaccination status of the cattle in question (Fukai, Morioka, Onozato, Yoshida, & Sakamoto, 2013;Sørensen et al, 1998). The sensitivity of this test in experimentally infected animals nears 100% (Brocchi et al, 2006).…”

Section: Survey Design Respondents and Serologymentioning

confidence: 99%

Estimating foot‐and‐mouth disease (FMD) prevalence in central Myanmar: Comparison of village headman and farmer disease reports with serological findings

Andel

Jones

Buckle

et al. 2019

The impacts of foot‐and‐mouth disease (FMD) on food security in developing countries are difficult to quantify due to the scarcity of accurate data on the prevalence and incidence of affected villages. This is partly due to resource constraints as well as the logistical challenges of conducting regular diagnostic testing in remote locations. In this study, we used descriptive analysis and latent class analysis (LCA) models to analyse data collected during a field survey of 160 villages in central Myanmar in the Mandalay and Sagaing Regions over the 2012–2016 time period. We evaluated the performance of verbal reports made by village householders and headmen against serological data to retrospectively determine the FMD‐infection status of our study area and to identify factors contributing to under‐reporting. Blood samples were collected from approximately 30 cattle per village in both the 6‐ to 18‐month age range and over 18‐month age range to distinguish between recent and historic exposure. Village householders were asked to identify pictures of FMD‐affected cattle amongst pictures of cattle affected with other common endemic diseases to assess the accuracy of their verbal reporting. The serological results confirmed that FMD is endemic in central Myanmar with village‐level seroprevalence estimated at 56% for animals 6–18 months of age and 80% when all age groups were considered together. Most village householders were familiar with the clinical signs of FMD‐affected cattle (72%). Based on the results from the LCA models, the village headman had a sensitivity of 77% and specificity of 75% for identifying FMD outbreaks in their village, whereas individual householders had a higher sensitivity and lower specificity of 80% and 56%, respectively. The level of disagreement between the different sources was correlated with the total number of cattle in the village and may potentially be worse in villages where endemic FMD may have led to a high level of natural immunity in cattle and subsequent masking of clinical signs. However, other regional effects such as the intensity of FMD extension efforts cannot be ruled out. Overall, the results suggest that verbal reports of FMD outbreaks from village headmen may be a useful tool to integrate into active FMD surveillance programmes in developing countries.