Caracterização morfológica de larvas infectantes de Libyostrongylus douglassii e Libyostrongylus dentatus (Nematoda, Trichostrongylidae) e adultos de Codiostomum struthionis (Nematoda, Strongylidae) parasitas de avestruzes (Struthio camelus)

Abstract

The aim of this work was differentiates infective larvae of Libyostrongylus douglassii, L. dentatus and Codiostomum struthionis allowing the differential diagnosis of those species among fecal cultures. For this, 10 adult ostriches were slaughtered, their proventriculum and caeca ware removed and adult parasites were collected. Females adults of L. douglassii and L. dentatus were separate in five samples of 100 females each. The samples were macerated individually and mixed with sterilized feces and culture fecal was performed to obtaining of infective larvae. Adults parasites of C. struthionis collected in the caeca were washed in saline solution (NaCl 0,09%) and quantified. All the parasites were fixed in A.F.A. for optical microscopy and adults of C. struthionis and infective larvae of Libyostrongylus spp. were fixed in Karnovsky solution for scanning electron microscopy. All proventriculum and 90% of the analyzed caeca were positive to the infection by Libyostrongylus spp. and C. struthionis, respectively. It is possible to distinguish L. douglassii of L. dentatus and C. struthionis by the morphology and length of the larvae sheath tail, that in L. douglassii is short and with acute ending different the other two species that are long and filamentous. For the differential diagnosis between L. dentatus and C. struthionis is more reliable the use of the morphology of the ending of the larvae tail that, in L. dentatus presents a knob in the extremity, this character is not observed in C. struthionis. Like this, this continues being the best parameter for the differentiation among these two species of gastrointestinals nematodes of the ostriches. The differentiation of the infective larvae of L. douglassii, L. dentatus and C. struthionis among fecal cultures will facilitate the diagnosis of this species, by researchers and breeders, favoring the knowledge of the biology of these nematodes.