Epidemic resurgence of a goat-specific syndrome simulating goat dermatitis in Punjab and Sindh provinces of Pakistan

Abstract

The present study describes epidemic resurgence of a goat-specific syndrome simulating goat dermatitis at six different places in Pakistani Punjab province and at two places in Sindh province after a lapse of 56 years. The occurrence of the syndrome was limited to February thru July 2004; being absent thereafter till May 2007. Cumulative attack rate of the syndrome was 0.2%; 37 of 181 goats in 11 flocks contracting the syndrome over a 6-month outbreak period. Age-specific attack rates were higher (54.97) in goats younger than 1 year than in goats older than this. Similarly, the overall case fatality rate was higher (88.46%) in goats younger than 1 year than in those older than 1 year (81.81%). None of the cohort sheep in flocks ( n = 11) comprising both goat and sheep developed the syndrome. Significant clinical signs included fever (41.1–42.2 °C), generalized appearance of prickly heat-like tiny reddish dermal papules which successively transformed into thick rubbery intradermal nodules, necrotic blackish striated ulcers, and punched dermal ulcers covered with saucer-shaped black scabs eventually shedding after 38–60 days. Smaller grayish-white nodules were also seen on tongue, gums and nares. Vesicles and pustules were not seen at any stage of the disease. Chicken embryos inoculated with the filtrate via chorio-allantoic membrane route did not support the growth of any microorganism. When the filtrate prepared from the nodules of naturally affected goats was smeared onto the scarified inner skin of the ear of Beetal goats previously, vaccinated against goat-pox, the inoculated goats developed hyperemia and pyrexia (40.5–42.2 °C) after 7–8 days followed by the appearance of dermal lesions compatible with those of spontaneously occurring syndrome. Intradermal inoculation of filtrate on the costal area of goats resulted in appearance of skin swellings and pyrexia 3 days postinoculation. This was followed by successive appearance of typical skin lesions of the syndrome. Goats inoculated with filtrate prepared from dermal lesions and papules in the wake of recovery from the syndrome, inoculated sheep, rabbits and guinea pigs did not develop skin lesions or fever. A 6-day treatment protocol based on the use of antibiotic, antipyretic, VitAD 3E and topical antiseptic with and without antiviral (ribavirin) had no effect on the severity as well as final outcome of the syndrome. Vaccination against goat-pox did not stop occurrence of new cases. Contrarily, autogenous caprination with supernatant prepared from rubbery nodules of affected goats stopped the further progression of the disease to yet unaffected goats. The recrudescence of a contagious fatal goat-specific syndrome over a wide geographical region after an apparent lapse of 56 years signifies the need to include this goat disease in active surveillance program of caprine diseases.