Seroprevalence of nasal myiasis in camels determined by indirect enzyme-linked immunosorbent assay utilizing the most diagnostic Cephalopina titillator larval antigens.

ABSTRACT

Background and Aim: Nasal myiasis is a serious parasitic disease among camels caused by Cephalopina titillator larvae that negatively affect animal health and production globally. The diagnosis of the infestation relies on postmortem examination of the head region, which considers a cause impeding treatment of live animals and may be misdiagnosed as central nervous system disorders. This study aimed to identify the most diagnostic larval antigen with the capacity for monitoring C. titillator infestation, and to estimate the seroprevalence of nasal myiasis in camels in Egypt, using indirect enzyme-linked immunosorbent assay (ELISA). Materials and Methods: Three hundred and six male camels of Egyptian and Sudanese breeds, aged 2-5 years, were clinically evaluated for respiratory and/or nervous disorders in Cairo Governorate, Egypt. At the time of slaughter, blood samples were collected from all examined animals. The postmortem examination of 38 animals was conducted. Salivary glands, hemolymph, and somatic antigens were extracted from the second and third larval instars. Results: The results revealed that the salivary gland antigen was the most potent antigen in detecting C. titillator specific total IgG antibodies compared to haemolymph and crude somatic antigens. Using receiver-operating characteristic curves and area under the curve, the salivary gland antigen had a sensitivity of 91.67% and a specificity of 92.31%, respectively. It has the highest positive predictive value, 95.7%, and negative predictive value, 85.7%. However, using somatic and hemolymph antigens revealed a sensitivity of 79.17% and 70.83% and a specificity of 76.9% and 84.6%, respectively. There was complete concordance between ELISA results and autopsy findings (true positive). One hundred and forty out of 306 (45.8%) camel serum samples were found to contain C. titillator. Conclusion: This study demonstrated that salivary gland antigen is more effective than somatic and hemolymph antigens in accurately detecting nasal myiasis in camels. In addition, determining the seroprevalence of nasal myiasis with the salivary gland antigen through indirect ELISA revealed that it is a prevalent disease among camels in Egypt. Periodic surveillance of the C. titillator prevalence is necessary for effective management and control measures.