The Cerrado is Brazil's tropical savannah, which is arguably under greater threat than the Amazon rainforest. The Cerrado Biome of tropical South America covers about 2 million km(2) and is considered a biodiversity hot spot which means that it is especially rich in endemic species and particularly threatened by human activities. The Cerrado is increasingly exposed to agricultural activities which enhance the likelihood of mixing parasites from rural, urban and wildlife areas. Information about ticks from the Cerrado biome is scarce. In this report tick species free-living, on domestic animals and on a few wild animals in two farms in the Cerrado biome (Nova Crixás and Araguapaz municipalities, Goiás State, Brazil) are described. Amblyomma cajennense was the first and Amblyomma parvum the second host-seeking tick species found. Only two other tick species were found free-living: one Amblyomma nodosum and three Amblyomma naponense nymphs. Cattle were infested with Boophilus microplus and A. cajennense. Buffalos were infested with B. microplus and A. parvum. Dogs were infested with A. cajennense, Amblyomma ovale, A. parvum and Rhipicephalus sanguineus ticks. Anocentor nitens, B. microplus, A. cajennense, and A. parvum were found on horses. Amblyomma auricularium were found attached to nine-banded armadillos and Amblyomma rotundatum to red-footed tortoise, cururu toads and a rattlesnake. The latter was also infested with an adult A. cajennense. No tick was found on a goat, a tropical rat snake and a yellow armadillo. Among the observations the infestation of several domestic animals with A. parvum seems be the main feature. It suggests that this species might become a pest. However, the life cycle of A. parvum in nature, as well as its disease vectoring capacity, are largely unknown. It would be important to determine if it is a species expanding its geographic range by adaptation to new hosts or if it has been maintained in high numbers at definite locations by specific and still undetermined conditions. A higher prevalence of A. cajennense in most Brazilian biomes, with the exception of rainforests, was already shown before. Thus this species is favored by deforestation and is an important research target as it is the most common vector associated with the Brazilian spotted fever.
Cerrado biome, the South American savannah, covers about 2 million km(2) and is very rich in endemic species but threatened by agriculture. In this report free-living tick species are presented, and their seasonal and relative distribution within the various phytophysiognomies in a small Cerrado reserve in Minas Gerais State, Brazil. Overall 2,694 free-living ticks were found during a 2 years sampling period with CO(2) traps and cloth dragging. Of these, 73.5% were Amblyomma cajennense and 0.6% Amblyomma dubitatum. All other ticks (25.9%) were retained as Amblyomma spp. Adults of A. cajennense peaked in spring, the nymphs in winter of both years. Amblyomma larval clusters were found in autumn and winter. Adult ticks (46.7%) and nymphs (39.5%) were most often found in woodlands, whereas most larval clusters were found in valley-side marshes (39%). Amblyomma cajennense, Anocentor nitens, Rhipicephalus (Boophilus) microplusand Rhipicephalus sanguineus ticks were found on domestic animals from neighboring properties. Search for Rickettsia in the hemolymph of 497 A. cajennense and one A. dubitatum ticks yielded negative results. Results confirmed earlier reports on the overwhelming prevalence of A. cajennense ticks in the Cerrado biome of Brazil and added information to habitat preferences of this tick species, a major vector in Brazil of the Rocky Mountain spotted fever.
This is a report of ticks species, parasite prevalence and infestation intensity of birds in a forest fragment (18° 56' 57" S and 48° 12' 14" W) within the Brazilian cerrado (savanna), in the municipality of Uberlândia, State of Minas Gerais, Brazil. A total of 162 birds from 26 species were captured. One adult tick, 296 larvae and 67 nymphs were found on passerine birds. Of these, it was identified 31 larvae and 27 nymphs of Amblyomma longirostre, 17 nymphs of A. nodosum, one A. cajennense larvae and one male of Rhipicephalus sanguineus. All other ticks were identified as Amblyomma sp. larvae (n = 264) or nymphs (n = 26). Overall tick infestation intensity and prevalence were 4.32 ticks/infested bird and 52%, respectively. Sampling of host-seeking ticks on the ground within the forest during a two-year period showed only five Amblyomma sp. nymphs and one adult male of A. nodosum whereas a search for ticks on domestic animals (cattle, horses and dogs) found Rhipicephalus (Boophilus) microplus ticks. Although identification was possible in only 27% of bird ticks there seemed to be no correlation between environmental and domestic animal and bird infestation. It can be assumed that bird infestation may occur above the ground or at specific sites not sampled.Keywords: Bird, tick, Ixodidae, Brazilian savanna. ResumoNeste trabalho, são apresentadas as espécies de carrapatos em aves silvestres, sua prevalência e a intensidade de infestação em um fragmento florestal (18° 56' 57" S e 48° 12' 14" W) do Cerrado, no município de Uberlândia, Estado de Minas Gerais. Foram capturadas 162 aves de 26 espécies, mas apenas as aves Passeriformes estavam infestadas. Nestas, foram encontrados um carrapato adulto, 67 ninfas e 296 larvas. Dentre os carrapatos foi possível a identificação de 31 larvas e 27 ninfas de Amblyomma longirostre, 17 ninfas de A. nodosum, uma larva de A. cajennense e um Rhipicephalus sanguineus macho. Todos os outros carrapatos foram classificados como larvas (n = 264) ou ninfas (n = 26) de Amblyomma sp. A intensidade de infestação e a prevalência de carrapatos foram de 4,32 carrapatos/ave infestada e 52%, respectivamente. Na pesquisa de carrapatos em vida livre sobre a vegetação do fragmento florestal, foram capturados apenas cinco ninfas de Amblyomma sp. e um macho adulto de A. nodosum, por um período de dois anos. Carrapatos da espécie Rhipicephalus (Boophilus) microplus foram encontrados parasitando bovinos, cavalos e cães domésticos da região. Mesmo considerando a identificação de apenas 27% dos carrapatos das aves, parece não haver correlação entre infestação ambiental, nos animais domésticos, com a infestação das aves. Pode-se supor que a infestação das aves ocorra acima do solo ou em locais específicos não pesquisados neste trabalho.Palavras-chave: Ave, carrapato, Ixodidae, cerrado.
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