Is orf infection a risk to expanding goat production in developing countries? A study from Lao PDR

Following increases in demand for goats in Laos and in adjacent Vietnam in Southeast Asia, reports of several outbreaks of suspected foot-and-mouth disease (FMD) were investigated in September-October 2016 in four Lao rural villages. The investigation involved clinical and pathological examination of infected animals, plus interviews of goat smallholder farmers (n = 33). Serum (n = 32) and oral and facial lesion tissue (n = 8) samples were collected, with sera submitted for serological tests for FMD and tissues examined by histopathology. The sera were negative for FMD antibodies and histopathology confirmed the lesions were due to orf virus infection. Of the farmers interviewed, 25 indicated that several of their goats displayed clinical signs of oral or facial skin disease, with lesions extending from the lips and surrounding tissue extending occasionally to the ears, although they were unable to provide a reliable response on when the disease first occurred. Of the average infected herd size of 9 goats, 3 displayed clinical signs consistent with orf and one animal (less than six months of age) died from or with suspected orf infection. The investigation concluded that these outbreaks were due to orf infection and it was highly unlikely that previous or concurrent exposure to FMD virus was a contributing risk factor. Extension programs are required to assist smallholder goat farmers improve their knowledge and practice of goat health and production. With a rapidly increasing population of goats in smallholder and more recently commercial goat production systems in Laos, improved biosecurity to manage the risks of infectious diseases including orf, is advised.