Atividade anticoagulante de extratos de glândulas salivares de thyrsopelma guianense (diptera: simuliidae), principal vetor de onchocerca volvulus (nematoda: onchocercidae) no Brasil

Abstract

Thyrsopelma guianense (Diptera:Simuliidae) is the main Onchocerciasis vector in the single brazilian foci (Yanomani and Ye’Kuana Indians). However, there is already some evidence of the introduction of onchocerciasis in the Indian area Waimiri-Atroari/ Presidente Figueiredo/AM. This disease is among the main tropical diseases of social impact, with estimated 18 million people infected world wide, and as the second cause of blindness after cataract. The disease is caused through the bite of the simulid infected with the filarial worm, Onchocerca volvulus (Nematoda:Onchocercidae). The feeding and transmission are facilitated due to the presence of a variety of compounds of the saliva, with the most diverse biological functions: anti-coagulants, anti-platelets, vase expanders, immune modulators, among others. In this work, is described a pioneer study about the salivary proteins of the main onchocerciasis vector in Brazil (T. guianense) in which it was detected 1.07 μg/ par of gland of total soluble protein. The protein profile showed 12 polypeptides, with three bands of molecular weight above 69 kDa; two bands between 69 - 45 kDa; four bands between 45 – 30 kDa (with two abundant bands, mainly in the ages of 24 and 48 hours); one band between 30-20 kDa also abundant and two bands in the range of 20-14 kDa, small proteins, abundant and present up to 72 hours. Coagulating bioassays showed that salivary gland extracts (SGE) act in the two ways of coagulation (intrinsic, extrinsic and commum), extending the plasma recalcification time, protrombine time, trombine time, partially activated tromboplastine time, and that the amount of protein affects directly the inhibition of the coagulate formation. This work is the first investigation of anti-coagulants in salivary glands of Thyrsopelma guianense, suggesting that future studies should be supported with the aim to understand the function of salivary proteins, to help in understanding the blood feeding mechanisms and the transmission of the parasite. This knowledge will be subsiding for future research of drugs that block tropical disease transmission and specially the onchocerciasis.