Dados do Trabalho

Título

Morphological description of the larva of the tick Amblyomma aureolatum (Acari: Ixodidae), a vector of Brazilian spotted fever

Introdução

Amblyomma aureolatum is popularly known as the “yellow dog tick”, since males and females have a golden-yellow color on the dorsal scutum. Domestic and wild carnivores are the primary hosts for the adult stage, while birds and rodents are for the immature stages. They accidentally parasitize humans and transmit the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever. Adults and nymphs have already been described, but the larval stage lacks morphological description. 

Objetivo (s)

The objective of the present study was to describe the larva of A. aureolatum. 

Material e Métodos

The larva was described through scanning electron and optical microscopy, bringing the following results:

Resultados e Conclusão

Idiosoma. Length from apices of scapula to posterior body margin 0.635±0.015 (0.607–0.648), maximum breadth 0.561±0.010 (0.535–0.569). Body outline oval, with 11 festoons without tubercles. Scutum, 0.321±0.013 (0.307–0.355) length, 0.431±0.006 (0.422–0.442) breadth; inornate, surface very shagreened, without punctations, outline subtriangular with posterior margin slightly sinuous. Eyes flat, located at lateral scutal angles at the level of scutal midlength. Gnathosoma. Length from apex of hypostome to posterior basis margin 0.188±0.005 (0.183–0.200), maximum breadth 0.174±0.003 (0.168–0.180). Basis capitula, dorsally triangular in shape, with straight posterior margin in the center and slightly convex at the lateral boarders, without cornua; posterior margin convex ventrally, with pointed lateral projections, without ventral cornua. Palpi cylindrical 0.127±0.002 (0.125–0.133) length. Articles II and III each more than twice as long as I and IV; sutures between all articles distinct. Hypostome compact, rounded apically, length from apices to ventral posthypostomal setae 0.102±0.002 (0.099–0.105), maximum breadth 0.042±0.001 (0.040–0.044), dentition 2/2 throughout with 7–8 teeth per row, apical corona with minute denticles. Legs. Coxa I, 0.102±0.004 (0.096–0.109) length, 0.106±0.004 (0.101–0.117) breadth, with 2 triangular spurs, the external stout and two to three times longer than internal. Coxa II 0.095±0.004 (0.089–0.102) length, 0.140±0.008 (0.130–0.154) breadth, with 1 short triangular spur. Coxa III 0.116±0.008 (0.101–0.127) length, 0.117±0.008 (0.107–0.130) breadth, with 1 short triangular spur. Trochanter without spur. Tarsus I 0.221±0.005 (0.213–0.229) length, 0.073±0.003 (0.066–0.078) breadth. Tarsus III 0.176±0.004 (0.168–0.184) length, 0.052±0.003 (0.046–0.059) breadth.

Palavras Chave

Amblyomminae; Ixodida; Parasitiformes; Rickettsiosis; Public health