Resumo:
The genus Sarcocystis has approximately 200 species and only 17 of them are known to infect
snakes. The discovery of Sarcocystis nesbitti, which has public health relevance, boosted the
development of new investigations in snakes. In Brazil, studies on Sarcocystis spp. infection in
snakes are scarce. Then, the current work aimed to test the role of common boa (Boa sp.) from
Salvador city as Sarcocystis spp. hosts, and consequently, to characterize the stages of the
parasite by morphological and molecular methods. Fecal samples obtained from 65 boa from
Salvador city were examined using a centrifugal-flotation method. The frequency of infection
in the tested snakes was 1.53% (1/65). From the single positive animal, six fecal samples were
available for analysis. Intermittent shedding of sporocysts and variation in the number of
excreted sporocysts occurred in this snake. Morphomethric evaluation of the parasites revealed
significant differences in sporocysts’ sizes (p < 0.05). In vivo experimentation was carried out
with two species of rodents Mus musculus (Balb/c, Balb /c Nude and knockout INF- γ-KO
mice) and Rattus norvegicus (Wistar rat), resulting in no infection in the mice. As the tissues of
the rats are still under histological processing, it has not been possible to generate data so far.
Molecular analysis of sporocysts derived from the common boa using 18S, 28S, and ITS-1
markers demonstrated changes in the chromatogram compatible with heterozygosis. Still, after
editing these sequences, and associating them with the mitochondrial COX-1 marker, the
sequences revealed a high identity with Sarcocystis spp. isolated from snake sporocysts and
rodent sarcocysts. Phylogenetic analysis revealed that the common boa sample does not possess
correspondence with any other known organism, representing a novel sequence.
