Epidemiology of Foot and Mouth Disease in Sheep and Goats in Punjab

Abstract

Foot and mouth disease (FMD) is a highly contagious disease of ruminants that causes huge economic losses around the globe. However, the prevalence of FMDV in small ruminants has been overlooked in Pakistan. The present study was designed to determine the sero-prevalence of FMD in sheep and goats in Punjab and to identify the prevalent serotypes of virus in sheep and goats in the study area. The efficacy of different commercial vaccines of FMD in sheep and goats under field conditions was also compared. The current study was completed in three phases. In 1 st phase, a seroepidemiological study was conducted in Chakwal, Faisalabad and Khanewal districts of Punjab, Pakistan to determine the prevalence of FMD in sheep and goats. A total 1200 serum samples were collected from sheep (n= 180) and goats (n= 920) and were subjected to 3ABC Non Structural Protein Enzyme Linked Immunosorbent Assay for detection of antibodies against non-structural proteins of FMD virus. In 2 nd phase of study, samples collected from clinical cases were confirmed for FMD virus using RT- PCR and serotyping of virus was done using indirect sandwich ELISA. In 3 rd phase of study, post-vaccine antibody titers were determined in sheep and goats using Indirect Haemagglutination Test (IHAT). One bivalent imported vaccine (Aftebin) and two trivalent vaccines (one imported vaccine, Aftovaxpur and one local vaccine, VRI-FMD) were tested. Results of 1 st phase of study showed that the overall seroprevalence of FMD in sheep and goats was 21 % (n=252) while 19.44 % (n=35) and 21.27 % (n=217) prevalence was recorded in sheep and goats respectively. Highest seroprevalence (32.5%) was observed in southern Punjab (Khanewal), followed by (25.75 %) central Punjab (Faisalabad) and the lowest seroprevalence (4.75 %) was detected in northern Punjab (Chakwal). There was no statistically significant difference in seroprevalence between sheep and goats. Among different risk factors tested, age and sex were found to be significantly associated with the prevalence of disease while pregnancy and herd type had no association with the prevalence of the disease. In 2 nd phase of study, a total of 4 outbreaks were reported during the study period and a total of 13 epithelial tissue samples were collected (10 from goats and 3 from sheep) from these outbreaks. Results with RT- PCR showed that 4 out of 13 field samples were FMD virus. All these 4 positive samples were taken from goats of district Khanewal. Indirect sandwich ELISA was applied to the samples for serotyping of FMD virus and all 4 positive samples were confirmed as IXserotype “O” of FMD virus. Results of 3 rd phase of study showed that highest Geometric Mean Titer against all 3 serotypes of virus was recorded in animals that were injected aftovaxpur followed by aftebin and VRI-FMD vaccine. The current study illustrate that FMD is highly prevalent in sheep and goats in Punjab. Therefore, a broader study is needed to ascertain the countrywide prevalence of FMD in small ruminants.