Epidemiological Aspects of Foot and Mouth Disease Outbreak in a Sheep Herd.

Present study is a detailed investigation on the occurrence and mortality caused by Foot and Mouth Disease (FMD) and its possible association with carrier status in a sheep herd in Islamabad capital territory (ICT) area of Pakistan. A total of 95 animals (50 adult and 45 young) were present in the herd at the start of the outbreak and about 22 out of 45 young ones (Age= 15-30 days) were died in a period of 2 weeks. Only 10 out of 50 adult sheep showed the clinical signs of the disease but the interesting feature of outbreak was that the kids from the clinically healthy sheep also develop the disease and expired. This experience is indicative of the possible excretion of virus in the milk of dam before the onset or without the clinical signs which is pointing towards the FMD carrier status in sheep. On postmortem of the dead animals, yellow streaks were found on the heart which is indicative of FMD virus infection. Later the sampling was performed from the infected dam showing the non-structural antibodies (NSP) for FMDV. The tissue samples for the morbid animals were tested for the presence of FMD antigen by Indirect Sandwich ELISA (Is ELISA) as well as RT-PCR. The samples from the heart tissue and blood were found positive for FMD antigen with serotype Asia-1. There was a high mortality rate in young ones (22/45) but the history revealed that the disease was present in the area during previous years but the clinical ailment was not severe. So it might be the emergence of serotype "Asia-1" in the sheep population which was linked to disease severity. It is worth-mentioning that no FMD vaccination is being carried out in small ruminants especially in animals with the nomads. [ABSTRACT FROM AUTHOR]