A review of the ticks (Acari, ixodida) of Brazil, their hosts and geographic distribution - 1. The state of Rio Grande do Sul, Southern Brazil

A review of the ticks (Acari, Ixodida) of the State of Rio Grande do Sul, s outhern Brazil, was completed as a step towards a definitive list (currentl y indicated as 12) of such species, their hosts and distribution. The ticks : Argas miniatus (poultry), Ixodes loricatus (opossums), Amblyomma aureolat um (dogs), A. calcaratum (anteaters), A. cooperi (capybaras), A. nodosum (a nteaters), A. tigrinum (dogs) (Neotropical) and Rhipicephalus sanguineus (d ogs) (introduced cosmopolitan, Afrotropical) were confirmed as present, in addition to the predominant, Boophilus microplus (cattle) (introduced, pant ropical, Oriental). Of the further 18 species thus far reported in the lite rature as present in the stare, but unavailable for examination: only Ornit hodoros brasiliensis (humans and their habitations) (Neotropical), Ixodes a ffinis (deer) (Nearctic/Neotropical) and I. auritulus (birds) (Nearctic/Neo tropical/Afrotropical/Australasian) are considered likely; 13 species would benefit from corroborative local data but the majority appear unlikely; re ports of A. maculatum (Nearctic/Neotropical, but circum-Caribbean) ar-e con sidered erroneous, the validity of A. fuscum is in doubt. The very recent, first known report of the tropical Anocentor nitens (horses)(Nearctic/Neotr opical), but still appal-ent absence of the tropical A. cajennense (catholi c) (Nearctic/Neotropical) and the sub-tropical/temperate ate Ixodes pararic inus (cattle) (Neotropical) in Rio Grande do Sul are important for consider ations on their current biogeographical distribution and its dynamics in So uth America. The state has relatively long established, introduced ("exotic "), Old World tick species (B. microplus, R. sanguineus) that continue to r epresent significant pests and disease vectors to their traditional, introd uced domestic animal hosts, cattle and urban dogs. There are also indigenou s, New World ticks (A. miniatus, O. brasiliensis, A. aureolatum, A. nitens) , as both long established and possibly newly locally introduced species in the state, that should be considered as potential and emergent pests and p athogen vectors to humans and their more recently acquired, introduced dome stic animal hosts; rural poultry, dogs and horses.