Prevalence and risk factors for foot and mouth disease infection in cattle in Israel.

Foot and mouth disease (FMD) is a highly contagious viral disease with major economic consequences. In Israel, FMD epidemics recur almost every year and mostly affect cattle. The highest number of outbreaks occurs among beef cattle farms, followed by feedlot farms and dairy farms. We performed several cross-sectional serological studies in Israel during 2006-2014, aimed to reveal if the virus is endemic among cattle and to determine the sero-prevalence of antibodies directed against non-structural proteins (NSP) of FMD virus. Additionally we aimed to determine the risk factors for such sero-positivity. A risk based sampling was performed and the presence of anti-NSP antibodies was estimated using the PrioCHECK(®) ELISA kit. Beef cattle showed the highest sero-prevalence (13.2%, CI95%=10.8-15.8%). Higher FMD sero-prevalence in beef cattle sampled in 2014 was associated with previous FMD outbreaks in the farm and with age (adult cows versus calves (p<0.05)). Sero-prevalence in feedlot calves was significantly lower with only one sero-positive calf out of 256 (0.4%, CI95%=0-2.2%). Sero-prevalence among dairy cattle was 2.7% (CI95%=2-3.6%) with location of up to 3km from FMD outbreaks in multiple farms and location of up to 5km from the nearest border standing out as significant (p<0.05) risk factors for sero-positivity. The extremely low sero-prevalence of FMD in feedlot cattle and the significant association of infection in beef cattle with previous outbreaks suggest absence of virus circulation between these two populations during the study period, although previous data show that during outbreaks such transmission can occur. Low sero-prevalence in dairy cattle located in areas adjacent to previous FMD outbreaks may be attributed to intense routine vaccination and stringent control measures that were applied during outbreaks such as emergency vaccination and strict quarantine. Early detection of FMD outbreaks among grazing beef herds as well as the implementation of control measures among these farms are therefore the methods of choice to prevent future outbreaks in Israel.

Association of the time that elapsed from last vaccination with protective effectiveness against foot-and-mouth disease in small ruminants.

Routine and emergency vaccination of small ruminants against foot-and-mouth disease (FMD) is mandatory in many endemic countries, yet data on the field effectiveness of the vaccines used is scarce. We conducted an investigation of a serotype O FMD outbreak that took place in a sheep and goat pen, and estimated the effectiveness of various routine vaccination statuses. We also evaluated the protection provided by colostrum administration and emergency vaccination. Animals which were routinely vaccinated twice were not clinically affected while disease incidence was observed among animals routinely vaccinated only once (p = 0.004 according to a two-sided Fisher's exact test). In groups vaccinated only once, there was a significant association between the average time that elapsed since last vaccination and the disease incidence (n = 5; Spearman correlation coefficient: rs = 1.0, p < 0.01). In addition, non-vaccinated lambs fed colostrum from dams vaccinated more than 2 months before parturition had a mortality rate of 33%. Administration of emergency vaccination 2 days after the occurrence of the index case was the probable reason for the rapid blocking of the FMD spread within 6 days from its onset in the pen.