Chigger mites (Trombidiformes: Trombiculidae) of small mammals from Brazil: morphological studies and investigation of the presence of pathogens

• Autor(a) principal: Jacinavicius, Fernando de Castro
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/10/10134/tde-25092019-104735/
• topic: 18S rDNA; 18S rDNA; Rickettsia; Chiggers; Mammalia; Mammalia; Rickettsia; Taxonomia; Taxonomy; Trombiculídeos

Chiggers are the popular name of larval stage of mites of the family Trombiculidae that parasite vertebrates, and during the parasitism, can cause a skin reaction in the host, known as trombiculiasis. Some species are vectors of tsutsugamushi, a human rickettsiosis, caused by the bacteria Orientia tsusugamushi. Furthermore, the presence of some pathogens has been detected in chiggers, as Coxiella, Hepatozoon and Rickettsia. To Brazil only the bacteria Ricekttsia felis-like was detected in the chigger species Blankaartia sinamaryi collected parasitizing a bird. In the Neotropical region this group of mites is currently poorly studied and there are gaps in taxonomy, biodiversity, and association with vertebrate. Considering in the lack of knowledge, and that there are indications of the possibility of the larvae participating in the transmission of pathogens in other regions of the world, the investigative analysis of Coxiella, Hepatozoon and Rickettsiain this group of mites in Brazil becomes relevant. National and international collections were consulted and the specimens collected parasitizing mammals were examined. Besides that, chigger mites collected recently were kept in colonies for the knowledge of nymph stages and all stages were used for molecular studies and in pathogen detection. By the end of this study, for the national territory 73 species are recorded, 17 species has been recorded in new localities in Brazil, 10 species are reported for the first time in the country, the deutonymph stage for one species was described, 24 new associations of chiggers parasitizing mammals in Brazil have been provided, two new species were described and the genus Arisoceruswas synonymized with the genus Herpetacarus. In addition, we provide the first report of the detection of strains of Rickettsia sp. in the chigger mites A. hertigi, Q. trapezoides, and T. bakeri collected on rodents in Brazil, including sequences of 18S gene of the species A. hertigi, Kymocta sp., Q. pazca, Q. trapezoides, and T. bakeri for the first time, increasing the genebank for this group of mites so diverse but still little known in Brazil.