Estudo da transmissão experimental de Borrelia anserina (Sakharoff, 1891) por Argas (Persicargas) miniatus Koch, 1844 e avaliação comparativa de parâmetros clínicos e hematológicos em Gallus gallus Linnaeus, 1758

Abstract

Avian spirochetosis is an acute septicemic disease, cosmopolite, of a variety of avian species caused by Borrelia anserina (Sakharoff, 1891). This spirochete is usually present in the blood of infected birds during the early stages of the disease. The present study assesses the experimental transmission of B. anserina by infected ticks Argas miniatus, observing the pre-patent and patent period, and comparing the clinical and hematological alterations. Twenty-seven fowls of the species Gallus gallus were randomly allocated into three groups composed by nine animals each. One group was exposed to B. anserina infected ticks (group 1), other one to ticks free of this agent (group 2), besides one group not exposed to ticks (group 3). Blood smears of the fowls were taken, daily, since the first day the fowls were exposed to the ticks, up to the 25º day after exposure (DAE). Blood samples were collected three days before exposure, three DAE, eight DAE, and for the last time in eighteen DAE for hematologic tests. The examination of group three s smears revealed a great number of spirochetes. The biological parameters of the pre-patent and patent period for this group were, 6 ± 0,83 and 5 ± 1,96 days, respectively. Group 2 and group 3 blood smears were negatives during the whole period under exam. About the clinical signs observed, since the sixth and seventh DAE, the fowls of group 1 presented: nibs bristle, pale crist, somnolence, inappetence, loss of weight and green diarrhoea wich were continuing until the 12º DAE coinciding with the end of the spirochetemia, after this, occured clinical evolution which self-cure. In agreement with the hematological evaluation results, the fowls exposed to infected ticks showed a normocytic normochromic anemia in eight DAE, leucocytosis with initial heterophilia and monocytosis in concomitance with the spirochetemia. After the patent period, eighteen DAE, a linphocytosis was detected. The present study confirmed the viability of the experimental transmission of B. anserina by infected ticks A. miniatus. Infected G. gallus with avian spirochetosis showed clinical alterations wich cursed in concomitance to the spirochetemia period, evoluting to selfcure, moreover hematological alterations compatible with the bacterial infection.