Spatio-temporal patterns of foot-and-mouth disease transmission in cattle between 2007 and 2015 and quantitative assessment of the economic impact of the disease in Niger.

Foot-and-mouth disease (FMD) is endemic in Niger, with outbreaks occurring every year. Recently, there was an increasing interest from veterinary authorities to implement preventive and control measures against FMD. However, for an efficient control, improving the current knowledge on the disease dynamics and factors related to FMD occurrence is a prerequisite. The objective of this study was therefore to obtain insights into the incidence and the spatio-temporal patterns of transmission of FMD outbreaks in Niger based on the retrospective analysis of 9-year outbreak data. A regression tree analysis model was used to identify statistically significant predictors associated with FMD incidence, including the period (year and month), the location (region), the animal-contact density and the animal-contact frequency. This study provided also a first report on economic losses associated with FMD. From 2007 to 2015, 791 clinical FMD outbreaks were reported from the eight regions of Niger, with the number of outbreaks per region ranging from 5 to 309. The statistical analysis revealed that three regions (Dosso, Tillabery and Zinder), the months (September, corresponding to the end of rainy season, to December and January, i.e., during the dry and cold season), the years (2007 and 2015) and the density of contact were the main predictors of FMD occurrence. The quantitative assessment of the economic impacts showed that the average total cost of FMD at outbreak level was 499 euros, while the average price for FMD vaccination of one outbreak was estimated to be more than 314 euros. Despite some limitations of the clinical data used, this study will guide further research into the epidemiology of FMD in Niger and will promote a better understanding of the disease as well as an efficient control and prevention of FMD.

Outbreak investigations and molecular characterization of foot-and-mouth disease viruses circulating in south-west Niger.

In Niger, the epidemiological situation regarding foot-and-mouth disease is unclear as many outbreaks are unreported. This study aimed (i) to identify Foot-and-mouth disease virus (FMDV) strains currently circulating in cattle herds, and (ii) to identify risk factors associated with Foot-and-mouth disease (FMD)-seropositive animals in clinical outbreaks. Epithelial tissues (n = 25) and sera (n = 227) were collected from cattle in eight districts of the south-western part of Niger. Testing of clinical material revealed the presence of FMDV serotype O that was characterized within the O/WEST AFRICA topotype. The antigenic relationship between one of the FMDV isolates from Niger (O/NGR/4/2015) and three reference vaccine strains was determined by the two-dimensional virus neutralization test (2dmVNT), revealing a close antigenic match between the field isolate from Niger and three FMDV serotype O vaccine strains. Serological analyses using a non-structural protein (NSP) test provided evidence for previous FMDV infection in 70% (158/227) of the sera tested. Multivariate logistic regression analysis revealed that only the herd composition (presence of both cattle and small ruminants) was significantly associated with FMDV seropositivity as defined by NSP-positive results (p-value = .006). Of these positive sera, subsequent testing by liquid-phase blocking ELISA (LPBE) showed that 86% (136/158) were positive for one (or more) of four FMDV serotypes (A, O, Southern African Territories (SAT) 1 and SAT 2). This study provides epidemiological information about FMD in the south-western part of Niger and highlights the complex transboundary nature of FMD in Africa. These findings may help to develop effective control and preventive strategies for FMD in Niger as well, as other countries in West Africa.