RESUMO
The performance of Fas2-ELISA for the diagnosis of Fasciola hepatica infection in children living in areas of high endemicity for fascioliasis in the Peruvian Andes is analyzed. Fas2-ELISA is based on the detection of circulating IgG antibodies elicited in infected individuals against a F. hepatica antigen termed Fas2. The study was conducted in three Andean localities, Huertas-Julcan in Junin, Asillo in Puno, and Cajamarca, with a total population of 634 children in an age range 1 to 16 years old. Child fascioliasis prevalence was 21.1% in Huertas-Julcan, 25.4% in Asillo, and 24% in Cajamarca, estimated by coprological inspection. The seroprevalence of F. hepatica infection, determined by Fas2-ELISA, was 27.8% in Huertas-Julcan, 44.6% in Asillo, and 29.1% in Cajamarca. The overall sensitivity of Fas2-ELISA was 92.4%, the specificity 83.6%, and the negative predictive value 97.2%. No association between OD(450) Fas2-ELISA and infection intensity measured by egg counting was observed. Results show that Fas2-ELISA is a highly sensitive immunodiagnostic test for the detection of F. hepatica infection in children living in human fascioliasis endemic areas.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/imunologia , Cisteína Endopeptidases/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Fasciola hepatica/imunologia , Fasciolíase/diagnóstico , Adolescente , Fatores Etários , Animais , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática/normas , Fasciolíase/epidemiologia , Fezes/parasitologia , Feminino , Helmintíase/epidemiologia , Humanos , Imunoglobulina G/sangue , Lactente , Intestinos/parasitologia , Masculino , Peru/epidemiologia , Prevalência , Infecções por Protozoários/epidemiologia , Fatores de Risco , Sensibilidade e EspecificidadeRESUMO
Circulating antibody against Fasciola hepatica antigens was determined by enzyme-linked immunosorbent assay (ELISA) and immunoelectrophoresis in alpacas naturally exposed to F. hepatica. Serological assay parameters were established by using sera from eight infected animals and seven controls with no record of this parasitic infection. Excretory--secretory (ES-) products, Fas1- and Fas2-ELISA were used to survey 307 alpacas from a F. hepatica endemic area in the Peruvian Andes. Seroprevalence of F. hepatica infection varied from 56.7, 64.8 and 66.8% measured by Fas1-, Fas2- and ES-ELISA, respectively. The sensitivity for ES-ELISA was 95%, corresponding Fas1- and Fas2-ELISA sensitivity values were 90 and 95%. In this population, 7% of animals were positive for F. hepatica eggs in faeces, other parasites detected were Trichuris sp. (40%), Nematodirus sp. (34.6%), Lamanema sp. (12.8%) and Eimeria sp. (11.8%). The results show that F. hepatica infected animals elicit circulating antibodies against ES, Fas1 and Fas2. Fas2-ELISA may be proposed as a sensitive assay for the immunodiagnosis of fasciolosis in alpacas.