RESUMO
Ascaris is a large roundworm parasite that infects humans and pigs throughout the world. Molecular markers have been used to study parasite transmission in Ascaris-endemic and -nonendemic regions of the world. In the United States, ascariasis still persists in commercial swine and has been designated a neglected disease of poverty in humans. However, relatively few data are available for evaluation of zoonotic transmission. In the present study, we obtained adult worms from abattoirs and characterized each worm on the basis of the gene encoding nuclear internal transcribed sequence (ITS) and mitochondrial cox1 Restriction fragment-length polymorphism analysis of ITS revealed swine, human, and hybrid genotypes. cox1 sequences were compared to all complete sequences available in GenBank, and haplotype analysis demonstrated 92 haplotypes worldwide. Sequences from the parasites in this study represented 10 haplotypes, including 6 new haplotypes that have not been previously described. Our results indicate that anthropozoonotic transmission has occurred in the past, resulting in the presence of human genotypes in pigs and supporting further investigation of zoonotic Ascaris transmission in the United States.
Assuntos
Ascaríase/veterinária , Ascaris/genética , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Adulto , Animais , Ascaríase/epidemiologia , Ascaríase/parasitologia , Ascaríase/transmissão , Ciclo-Oxigenase 1/genética , DNA de Helmintos/genética , DNA Espaçador Ribossômico/genética , Genótipo , Saúde Global , Haplótipos , Humanos , Iowa/epidemiologia , Filogenia , Suínos , Doenças dos Suínos/transmissão , Zoonoses/epidemiologia , Zoonoses/parasitologia , Zoonoses/transmissãoRESUMO
Toxocara vitulorum, an ascarid that infects bovines, is largely considered a parasite of tropical and sub-tropical areas of the world. Infections in more temperate climates have been reported but little is known about T. vitulorum transmission in North America. Herein, we detail an investigation of an Iowa beef farm where necropsy of a 20 day old beef calf revealed a mass of large ascarid nematodes occluding the small intestine. Gross histopathological, and molecular features of nematodes recovered from the calf were consistent with T. vitulorum. Fecal samples obtained from calves in the herd revealed 14 of 34 (40%) were shedding T. vitulorum eggs. Calves continued to shed eggs following a single dose of a topical moxidectin product. These results suggest that T. vitulorum may be more widespread in the United States than previously recognized. Due to the pathogenic nature of this parasite, further investigation into the prevalence and transmission of T. vitulorum in North America is warranted.