SWINE VARIOLA: STUDY ON THE OCCURRENCE OF THE OUTBREAKS IN SÃO PAULO AND TOCANTINS STATES, BRAZIL

ABSTRACT

The present study was aimed at the evaluation of the outbreaks of swine smallpox, in the sates of São Paulo and Tocantins, Brazil, that occurred during the period 1976 to 2001. All the animals affected by the disease presented lesions, in most cases, localized in the abdominal and inguinal regions and in the head (ears and muzzle), which first appeared as erythematosus areas, evolving into papules and postules, which transformed into crusts. The disease was experimentally reproduced, the inoculated swines presenting clinical aspects similar to the ones of the outbreaks. Transmission electron microscopy detected particles of ortopoxvirus in all the examined samples. There was no virus growth in the chorion allantoid membrane of embryoned eggs nor in the cells of bovine kidney, while accentuated infection was observed in the primary cultivation of kidney cells from newborn pig, resulting in a clear cytopathic effect. This fact, in conjunction with the characteristic histopathologic lesions and the constant presence of particles of poxvirus, leads to the conclusion that this is a case of swine smallpox virus.

KEY WORDS:
Swine pox; poxvirus; ultrastructure.