Immature argasid ticks: diagnosis and keys for neotropical region / Carrapatos argasídeos imaturos: diagnoses e chaves para a região neotropical

Many argasid tick species are known only through their larval descriptions, in which the chaetotaxy, together with other external morphological characteristics, has been used to separate genera and species. However, the illustrations of these features are based on optical microscopy alone and many of these features are not clearly defined. Because of the difficulties in determining the larval and nymph stages of some genera, we have prepared illustrated keys for the immature stages of argasids, including an up-to-date list of the known species of the Neotropical region. We have also included an illustrated key for larvae of the Ornithodoros species from Brazil, based on scanning electron microscopy.

Muitos carrapatos argasídeos são conhecidos somente por descrições larvais, nas quais a quetotaxia associada a outros caracteres morfológicos tem sido usada para separar gêneros e espécies. No entanto, as ilustrações sobre esses caracteres são baseadas somente em microscopia óptica e muitos deles não estão claramente definidos. Devido às dificuldades em determinar estágios larvais e ninfais de alguns gêneros, elaboramos chaves ilustradas para os estágios imaturos de argasídeos, incluindo uma lista atualizada de espécies conhecidas da região Neotropical. Incluímos também uma chave ilustrada para larvas das espécies de Ornithodoros do Brasil baseada em microscopia eletrônica de varredura.

Ticks (Acari: Ixodida: Argasidae, Ixodidae) infesting humans in Northwestern Cordoba Province, Argentina

Ticks infesting humans were collected from September 2004 to August 2005 in Northwestern Córdoba in an area with a southern limit in the locality of Dean Funes (30°25´S 64°20´W) and San José de las Salinas (30°00´S 64°37´W) in the North. The collections consisted in ticks found attached on man obtained from three sources: 1) specimens fixed on two workers during two successive days per month of field work in the northern part of the area which belongs to Western Chaco district of the hytogeographical Chaco domain, 2) ticks attached to a man working in a farm close to Dean Funes in the Chaco Serrano district of the Chaco domain and, 3) ticks collected from a collaborator visiting daily a suburban property with dogs in the vicinities ofDean Funes. Most ticks collected were larvae, nymphs and adults of Amblyomma neumanni from the Chaco Serrano district where a nymph of Otobius megnini was also found on man. Adults of Amblyomma parvum and Amblyomma tigrinum were detected feeding on humans in the Western Chaco district and in the property close to Dean Funes, respectively. Amblyomma neumanni was absent on man from December to April while most specimens of A. parvum and A. tigrinum were collected during summer. Their role as potential vector of ticktransmitted diseases in the area is unknown.

Se recolectaron garrapatas (Acari: Ixodida: Argasidae, Ixodidae)infestando humanos entre septiembre de 2004 y agosto de 2005 en un área del noroeste de Córdoba cuyo límite al sur es la localidad Deán Funes (30º25´S 64°20´W) y el límite al norte es la localidad de San José de las Salinas (30°00´S 64°37´W). Las colecciones consistieron en garrapatas fijadas a humanos obtenidas de tres fuentes: 1) garrapatas fijadas sobre dos trabajadores durante dos días sucesivos por mes de trabajo de campo en la parte norte del área, la cual pertenece al distrito chaqueño occidental del dominio fitogeográfico del Chaco, 2) garrapatas fijadas a un trabajador en un campo cercano a Deán Funes en el distrito chaqueño serrano del dominio del Chaco y 3) garrapatas recolectadas de un colaborador que visitaba diariamente una propiedad suburbana con perros en las vecindades de Deán Funes. La mayoría de las garrapatas recolectadas fueron larvas, ninfas y adultos de Amblyomma neumanni del distrito chaqueño serrano donde una ninfa de Otobius megnini fue también encontrada sobre humano. Adultos de Amblyomma parvum y Amblyomma tigrinum se detectaron alimentándose sobre humanos en el distrito Chaqueño occidental y en la propiedad cercana a Deán Funes respectivamente. Amblyomma neumanni estuvo ausente sobre humano de diciembre a abril mientras que la mayoría de lo especímenes de A. parvum y A. tigrinum fueron recolectados durante el verano. Sus papeles como potenciales vectores de enfermedades transmitidas por garrapatas en el área es desconocido.