Tick infestation of livestock and tick control methods in Brazil: A situation report

Abstract

Boophilus microplus is Brazil's outstanding livestock ectoparasitic pest (annual losses, US$ 1B), affecting, to varying extents, all its States, with a national herd of some 130 M cattle. The country's 8.5 M sq km and 23,000 km of land frontier with 10 tick infested countries complicate any concepts of national campaigns. Whereas Brazil is increasingly climatically suitable for B. microplus from south (three generations annually) to central (four) to north (potentially up to five), direct problems caused are incidentally decreased due to greater use of Bos indicus cattle at lower stocking rates; five tick population survival mechanisms are suggested. Voluntary, empirical chemical tick control remains the tradition, with little government involvement. Formamidine and synthetic pyrethroid acaricides dominate the market, due to former tick resistance to arsenicals, organochlorines and organophosphates, and market forces. Plunge dips, various sprayers, and “pour-on” formulations are used; first suspicions of tick resistance to synthetic pyrethroids have been reported. Various ecologically based “improved” tick control schemes produced promising results experimentally, but require a complementary vaccine against babesiosis/anaplasmosis before wide recommendation. Intensive use of synthetic pyrethroid acaricides has created tick-borne diseases and heightened demand for a live, frozen “vaccine”, in its pre-commercialization phase in Brazil. A strategic research and development approach has been adopted for widespread improvement to cattle ticks and tick-borne disease control in Brazil.