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Dichotomic and pictorial taxonomic key for larvae of the genus Amblyomma (Parasitiformes: Ixodidae) that occur in Brazil, using optical and scanning electron microscopy for description and morphological redescription of the larval stage

Grant number: 19/03167-0
Support type:Research Grants - Young Investigators Grants
Duration: February 01, 2020 - January 31, 2024
Field of knowledge:Agronomical Sciences - Veterinary Medicine
Principal Investigator:Thiago Fernandes Martins
Grantee:Thiago Fernandes Martins
Home Institution: Superintendência de Controle de Endemias (SUCEN). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
Assoc. researchers:Adriano Pinter dos Santos ; Agustin Estrada-Peña ; Marcelo Bahia Labruna ; Pablo Henrique Nunes ; Vera Lucia Fonseca de Camargo Neves
Associated research grant:17/50345-5 - Institutional development plan in research and technology for surveillance and control of vectors of the Superintendence of Endemic Diseases Control - SUCEN , AP.PDIP


Ticks of the genus Amblyomma have the greatest medical and veterinary importance in Brazil, since ticks of this genus parasitize wild animals, domestic and accidentally humans that enter rural and forest areas for work and recreation purposes. Tick larvae of the genus Amblyomma are quite aggressive to humans and are frequently documented both in human parasitism and in the transmission of Brazilian spotted fever and other rickettsial diseases in the country. However, due to the lack of morphological description of many of the larvae of the species of Amblyomma ticks occurring in Brazilian territory, together with the lack of a complete taxonomic key for these ticks, very little is known about the species of Amblyomma larvae which parasitize humans and animals in the country. In Brazil, the vast majority of studies of systematics, bioecology and tick control have been concentrated in the nymphal and adult stages of Amblyomma, since they are the two stages in which there are morphological descriptions and taxonomic keys for all species known up to the present moment. In the present research project, the description and morphological redescription of the larval stage of ticks of the genus Amblyomma using molecular techniques, optical and scanning electronic microscopy, morphometry, chaetotaxy and porotaxy will be performed for the larval stage of the 31 species of this genus that occur in the national territory. It will include 12 species for which the larval stage remains without description: A. aureolatum, A. cajennense, A. coelebs, A. fuscum, A. goeldii, A. humerale, A. incisum, A. latepunctatum, A. naponense, A. pseudoconcolor, A. scalpturatum, and A. yucumense. A dichotomic and pictorial taxonomic key with important features illustrated by optical and scanning electron microscopy will be constructed for the larvae of the 31 Amblyomma species that make up the Brazilian fauna of Amblyomma. In addition to the 12 species mentioned above, the other 19 species included in this identification key with their morphological descriptions already reported in the literature are: A. auricularium, A. brasiliense, A. calcaratum, A. dissimile, A. dubitatum, A. geayi, A. longirostre, A. nodosum, A. oblongoguttatum, A. ovale, A. pacae, A. parkeri, A. parvum, A. romitii, A. rotundatum, A. sculptum, A. tigrinum, A. triste, and A. varium. Through the construction of the present taxonomic key, the medical-veterinary importance, the geographical distribution through acarological maps and the hosts of the larval stage will be possible in the future for each species, and can thus contribute significantly to the reduction of agents transmitted by ticks to human beings within the Brazilian territory. (AU)