RESUMO
A Brazilian fox (Lycalopex vetulus) was rescued from a highway, and 16 days after maintained in captivity, the fox shed oocysts with sizes compatible with Hammondia sp. and Neospora caninum. DNA extracted from oocysts were initially tested in two PCRs targeting the internal transcribed spacer 1 (ITS-1) of the rDNA of Hammondia heydorni and the Nc-5 gene of N. caninum. A 270-bp product was visualized in the PCR for H. heydorni. No amplification was observed for N. caninum PCR. Since ITS-1-based PCR is not sufficient to differentiate Hammondia species derived from canids, oocyst DNA was examined using multilocus sequence analysis of five genetic fragments [intron 1 of the alpha tubulin gene (intron 1), internal transcribed spaces 1 and 2 (ITS-1 and ITS-2) of the rDNA, 28S rRNA gene (D2/D3 domain), and heat shock protein 70 (Hsp70)]. The Hammondia sp. oocyst from the Brazilian fox, referred here as H-FOXBR isolate, is closely related to H. heydorni and Hammondia triffittae, but differs from these parasites in three genetic markers (alpha tubulin gene, ITS-2, and 28S rRNA). As reported by other research groups, Hammondia spp. excreted by canids are genetically diverse and may encompass additional species besides H. heydorni and H. triffittae. In this study, we confirmed that H-FOXBR has significant genetic differences in comparison to H. heydorni and H. triffittae and may represent a separate species. Further studies are needed to identify the life cycle of this parasite and to characterize the parasite stages in the intermediate and definitive hosts.
Assuntos
Coccidiose/veterinária , Raposas/parasitologia , Oocistos/isolamento & purificação , Sarcocystidae/isolamento & purificação , Animais , Brasil , Coccidiose/parasitologia , DNA Intergênico/genética , DNA Ribossômico/genética , Fezes/parasitologia , Variação Genética , Proteínas de Choque Térmico HSP72/genética , Neospora , Reação em Cadeia da Polimerase , RNA Ribossômico 28S/genética , Sarcocystidae/genética , Tubulina (Proteína)/genéticaRESUMO
The present study aimed to detect and characterize antigenic proteins and to assess their activity as preventive vaccines against dermatobiosis. Polyclonal antibodies were produced against three larval instars (L(1), L(2), L(3)), and their antigenic proteins were assessed for reactivity. Polyclonal antibodies produced in animals immunized with extracts were analyzed, and L(3)-derived antibodies showed proteins with better antigenic responses. The study of reactivity using immunodetection showed that the 50-kDa protein had the highest antigenicity. This protein was purified and subjected to mass spectrometry, and the sequences obtained were compared with those in the databases available. No similarities were found with existing sequences. Subsequently, large quantities of purified protein were used to immunize cattle. Vaccine effectiveness was evaluated by comparing the number of cutaneous nodules formed in the control group and immunized animals. The antigen produced proved a promising candidate for vaccine production, with 90.67 % efficacy. Immunohistochemistry of antigen-antibody reaction in larval sections showed epitopes all over larval tissues.