Nicole Brand Ederli

Morphological diagnosis of infective larvae of Libyostrongylus douglassii (Cobbold, 1882) Lane, 1923 and L. dentatus Hoberg, Lloyd and Omar, 1995 (Nematoda: Trichostrongylidae) of ostriches.

The differentiation of the species of the Libyostrongylus genus is only possible with the obtainment of the adult parasites in the ostriches proventriculus and gizzard. The present work confirms that it is possible to differentiate the infective larvae of L. douglassii and L. dentatus allowing the differential diagnosis of these species by fecal culture. To show this, adult females from both species were collected from ten proventriculus from adult ostriches and separated by species. Both groups were macerated individually added to sterilized feces for standard fecal cultures. The infective larvae were recovered, identified, quantified and measured. All proventriculus analyzed were parasitized by Libyostrongylus spp. and a clear heterogeneous location for each species was observed. The infective larvae from the fecal cultures of macerated L. douglassii presented a mean total length of 874.3+/-33.80 microm, and a short sheath tail (29.5+/-4.11 microm) with acute termination. The infective larvae from the macerated L. dentatus presented mean total length of 856.0+/-43.63 microm, long sheath tail (61.2+/-9.52 microm) with filamentous termination. The mean measures of the tails of both species had a significant difference. The differentiation of the infective larvae of L. douglassii and L. dentatus by fecal cultures will facilitate the diagnosis of both species for further understanding the Libyostrongylus biology.

Didelphis aurita (Marsupialia: Didelphidae): A New Host for Sarcocystis lindsayi (Apicomplexa: Sarcocystidae)

Abstract: Nine opossums, Didelphis aurita, were captured in the city of Seropédica, State of Rio de Janeiro, Brazil and examined for species of Sarcocystis. Sporocysts were observed in the mucosal scrapings of the small intestine from 3 opossums. Five budgerigars, Melopsittacus undulatus, were infected with sporocysts from each of these infected opossums and 5 budgerigars were used as controls. Of the 15 sporocyst-treated budgerigars, 5 birds that received sporocysts from 1 of the infected opossums developed tissue parasites. Meronts in the vascular endothelium of the lung venous capillaries and cysts in the skeletal and cardiac muscle cells were observed in histological sections stained with hematoxylin and eosin. The microscopic cysts, which were predominantly in the tongue and leg muscles, ranged from 65.3 to 118.1 μm in length and 14.0 to 29.4 μm in width and from 0.9 to 1.9 μm in thickness of the cystic wall. Sections examined by transmission electron microscopy revealed that the cyst wall contained numerous slender and jagged-shaped protrusions, each with a finger-like formation at the end. The morphology, especially of the cyst wall, and the morphometry of the tissue cysts indicate that the parasite is Sarcocystis lindsayi and, therefore, the opossum, D. aurita, is now considered a definitive host for this species in Brazil.

Pathological findings in the caeca of naturally infected ostriches, Struthio camelus Linnaeus, 1758 (Aves, Struthionidae) parasitized by Codiostomum struthionis (Horst, 1885) Railliet and Henry, 1911 (Nematoda, Strongylidae).

In order to characterize lesions associated with Codiostomum struthionis in ostriches, 10 caeca were examined on both macro- and microscopic levels. Parasites were found in the distal third of the caecum and characterized as C. struthionis. Thickened mucosa was identified macroscopically where parasites were observed in high concentrations. Nodular areas were also observed in the distal third of the infected caeca, as well as hemorrhagic areas abutting small ulcers surrounded by edema. These findings were not observed in healthy controls. The concentration of C. struthionis found in infected animals was directly correlated with the severity of lesions observed in each caecum. These results allowed us to infer that C. struthionis is responsible for lesions in ostrich caeca.