Geographical distribution of Amblyomma cajennense (sensu lato) ticks (Parasitiformes: Ixodidae) in Brazil, with description of the nymph of A. cajennense (sensu stricto)

Abstract

BackgroundUntil recently, Amblyomma cajennense (Fabricius, 1787) was considered to represent a single tick species in the New World. Recent studies have split this taxon into six species. While the A. cajennense species complex or A. cajennense (sensu lato) (s.l.) is currently represented by two species in Brazil, A. cajennense (sensu stricto) (s.s.) and Amblyomma sculptum Berlese, 1888, their geographical distribution is poorly known.MethodsThe distribution of the A. cajennense (s.l.) in Brazil was determined by morphological examination of all lots of A. cajennense (s.l.) in two large tick collections of Brazil, and by collecting new material during three field expeditions in the possible transition areas between the distribution ranges of A. cajennense (s.s.) and A. sculptum. Phylogenetic analysis inferred from the ITS2 rRNA gene was used to validate morphological results. Morphological description of the nymphal stage of A. cajennense (s.s.) is provided based on laboratory-reared specimens.ResultsFrom the tick collections, a total 12,512 adult ticks were examined and identified as 312 A. cajennense (s.s.), 6,252 A. sculptum and 5,948 A. cajennense (s.l.). A total of 1,746 ticks from 77 localities were collected during field expeditions, and were identified as 249 A. cajennense (s.s.), 443 A. sculptum, and 1,054 A. cajennense (s.l.) [these A. cajennense (s.l.) ticks were considered to be males of either A. cajennense (s.s.) or A. sculptum]. At least 23 localities contained the presence of both A. cajennense (s.s.) and A. sculptum in sympatry. DNA sequences of the ITS2 gene of 50 ticks from 30 localities confirmed the results of the morphological analyses. The nymph of A. cajennense (s.s.) is morphologically very similar to A. sculptum.ConclusionOur results confirmed that A. cajennense (s.l.) is currently represented in Brazil by only two species, A. cajennense (s.s.) and A. sculptum. While these species have distinct distribution areas in the country, they are found in sympatry in some transition areas. The current distribution of A. cajennense (s.l.) has important implications to public health, since in Brazil A. sculptum is the most important vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1460-2) contains supplementary material, which is available to authorized users.

Current status of ticks and tick-host relationship in domestic and wild animals from Pantanal wetlands in the state of Mato Grosso do Sul, Brazil

“…After the reassessment of the taxonomic status and distribution of A. cajennense in Brazil (Nava et al 2014;Estrada-Peña et al, 2014;Martins et al, 2016) we assume that all records from Brazilian Pantanal are A. sculptum. Moreover, we review our field samples and all ticks are A. sculptum.…”

“…Moreover, we review our field samples and all ticks are A. sculptum. The distribution of A. sculptum in Brazil generally encompass the entire Cerrado and Pantanal biomes and great part of the Atlantic forest biome (Martins et al, 2016).…”

Amblyomma sculptum: genetic diversity and rickettsias in the Brazilian Cerrado biome

“…Amblyomma cajennense s.s . is associated with the Amazonian region, and its equatorial climate, and there is no evidence that the species participates in tick‐borne disease (TBD) transmission (Nava et al ., ; Martins et al ., ). By contrast, in Brazil A. sculptum occurs in the Cerrado (tropical savanna), Atlantic rainforest, Pantanal and Caatinga biomes (in areas with tropical climate).…”

“…and A. sculptum may occur in sympatry. Under such circumstances, identifying correctly the two species may be difficult (Martins et al ., ), and consequent errors in epidemiological studies may occur.…”

Diversidade De Carrapatos (Acari: Ixodidae) Em Animais Silvestres Recebidos Pelo Zoológico Municipal De Guarulhos

“…Os carrapatos foram identificados em estereomicroscópio, utilizando-se chaves taxonômicas (BARROS-BATTESTI et al, 2006;MARTINS et al, 2010;MARTINS et al, 2016) e posteriormente tombados no acervo da "Coleção Nacional de Carrapatos Danilo Gonçalves Saraiva" (CNC) da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, sob os números de tombo (3403)(3404)(3405)(3406)(3407)(3408).…”