RESUMO Os ácaros macronissídeos são ectoparasitas de vertebrados terrestres. Nós montamos e reexaminamos material de ácaros coletado em uma expedição entre 1987-1989 à Estação Ecológica de Maracá, Estado de Roraima, Brasil. Os espécimes foram identificados como Acanthonyssus proechimys Yunker e Saunders (Mesostigmata: Macronyssidae), que haviam sido coletados parasitando um echimídeo sul-americano, Proechimys sp. Este é o primeiro registro de Acanthonyssus no Brasil.

ABSTRACT Macronyssid mites are ectoparasites of terrestrial vertebrates. We slide-mounted and re-examined mite material collected in a 1987-1989 expedition to Maracá Ecological Station, Roraima State, Brazil. The specimens were identified as Acanthonyssus proechimys Yunker and Saunders (Mesostigmata: Macronyssidae), which were collected parasitizing a South American spiny rat, Proechimys sp. This represents the first record of Acanthonyssus in Brazil.

Un total de 50 caninos de áreas rurales de los estados Lara, Yaracuy, Carabobo y Falcón, Venezuela, fueron examinados visualmente y mediante palpación cutánea con el fin de detectar la presencia de garrapatas. Ninguno de los animales se encontró parasitado por Rhipicephalus sanguineus, la garrapata común del perro. Se colectaron 139 especimenes adultos del género Amblyomma Koch, 1844: 72 hembras y 65 machos de la especie Amblyomma ovale Koch, 1844, y dos hembras de la especie Amblyomma triste Koch, 1844. La identificación de los especimenes se realizó mediante observación en lupa estereoscópica y con la ayuda de claves taxonómicas. Los Estados donde se colectó el mayor número de ixódidos fueron Falcón con 52 especimenes y Lara con 49, representando 38 y 36%, respectivamente. A. ovale ha sido reportada como vector natural de Hepatozoon canis en áreas rurales. La especie A. triste fue colectada sólo en un canino del estado Yaracuy. Esta especie ha sido incriminada como el vector biológico de varios agentes rickettsiales patógenos, tanto para humanos como para animales domésticos y salvajes, por lo que se resalta la importancia del género Amblyomma en la transmisión de enfermedades zoonóticas.

Fifty dogs from the rural areas of Lara, Yaracuy, Carabobo and Falcón States of Venezuela were sampled through the visual and touch techniques in search of the presence of ticks. All the dogs were free of the brown dog tick Rhipicephalus sanguineus. A total of 139 adult ticks of the genus Amblyomma Koch, 1844 were collected: of them, 65 males and 72 females were identified as Amblyomma ovale Koch, 1844, whereas two females belonged to the species Amblyomma triste Koch, 1844. The observation through stereomicroscope, as well as the use of taxonomic keys, were employed in the identification of the collected specimens. Most of the ticks were collected in Falcón and Lara States, totalling 52 (38%) and 49 (36%), respectively. The species A. ovale has been reported as a natural vector of the protozoan Hepatozoon canis in rural areas. A. triste was collected only in one dog in Yaracuy State. This species has been incriminated as a biological vector of several rickettsial agents to the men and animals. The actual role of the genus Amblyomma as vector of zoonotic disease agents is highlighted.

This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of São Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi), and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus) were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting fleas, whereas Rickettsia bellii was the only agent infecting ticks, but no animal or human blood was shown to contain rickettsial DNA. Testing animal and human sera by indirect immunofluorescence assay against four rickettsia antigens (R. rickettsii, R. parkeri, R. felis, and R. bellii), some opossum, dog, horse, and human sera reacted to R. rickettsii with titers at least four-fold higher than to the other three rickettsial antigens. These sera were considered to have a predominant antibody response to R. rickettsii. Using the same criteria, opossum, dog, and horse sera showed predominant antibody response to R. parkeri or a very closely related genotype. Our serological results suggest that both R. rickettsii and R. parkeri infected animals and/or humans in the studied areas.

Polygenis (Polygenis) platensis s. l. (Jordan & Rothschild) foi assinalada pela primeira vez no Brasil nos municípios de Capão da Canoa, Tramandaí e Osório, RS. Novos registros de hospedeiros são dados para a espécie, com a inclusão de Ctenomys flamarioni (Travi) e Ctenomys minutus (De Blainville). Variações morfológicas foram também observadas entre os espécimes coletados sobre mesma espécie de hospedeiro e em mesma localidade, evidenciando alguma hibridização entre as duas subspécies e impossibilitando a determinação do status subespecífico. O número de espécies de pulgas conhecidas para o Brasil é aumentado para 60.

Polygenis (Polygenis) platensis s. l. (Jordan & Rothschild) is recorded for the first time from Brazil in the municipalities of Capão da Canoa, Tramandaí and Osório, RS. New host records for this flea include Ctenomys flamarioni (Travi) and Ctenomys minutus (De Blainville). Morphological variations were also observed among the flea specimens collected on the same species of host at the same municipality, evidencing some hybridization between the two subspecies and disabling the determination of the subspecific status. The number of known species of Brazilian Siphonaptera is now 60.

O estudo baseou-se em 208 espécimes, coletados em uma ampla faixa geográfica situada entre os centros do Brasil e da Argentina. Morfologicamente, as características utilizadas para a identificação de Polygenis (Polygenis) rimatus (Jordan) foram estudadas, tais como a presença ou ausência do duto da espermateca com margens espessadas e a forma da margem posterior do esternito VII, entre as fêmeas, bem como o ângulo entre os braços proximal e distal do tubo interno do aedeagus e o número de suas circunvoluções, nos exemplares machos. Os resultados obtidos são importantes para subsidiarem o reconhecimento da espécie. A variabilidade de algumas características entre exemplares de localidades disjuntas no Brasil e Argentina é também noticiada.

The study was carried out on the basis of 208 specimens of both sexes from a wide geographical range, from central Brazil to central Argentina. The morphology of diagnostic features of Polygenis (Polygenis) rimatus (Jordan) including the presence or absence of the ductus of the spermatheca with a thick wall, the shape of the posterior margin of seventh sternum in females, and the size of the angle between the distal and the proximal arms of the basal part of the aedeagal tubus, and the number of convolutions made by the coil of the aedeagal tubus interior in males, have been studied. The results obtained are important in clarifying some difficulty in species recognition. Besides, the variability of some characteristics between specimens from disjoint localities in Brazil and Argentina is also noticed.