Feline heartworm disease, caused by the filarial nematode Dirofilaria immitis, has been diagnosed with increased frequency in areas endemic for canine heartworm infection. The routine methods for determining the infection status of dogs, such as identification of circulating microfilariae in blood or identification of circulating antigen in serum, plasma or blood, have proven inadequate for screening cats. The inadequacies are due to the likelihood of single-sex infections and clinical disease during prepatent infections. Current antibody detection methodologies rely on crude or partially purified worm antigen preparations that may result in poor specificity. This report describes the cloning, expression, and diagnostic utility of the D. immitis homologue (PDi33) of the Onchocerca volvulus aspartyl protease inhibitor (Ov33). PDi33 is present in all stages that occur in the mammalian host (microfilariae, L3, L4, adult males, and females) and is released by adults cultured in vitro. An indirect enzyme-linked immunosorbent assay (ELISA) using antibody to recombinant PDi33 as a diagnostic marker for infection in cats was very sensitive and was useful for identifying prepatent infections. Testing of sera from cats infected with common gastrointestinal parasites also indicated excellent specificity. The same ELISA in dogs, although demonstrating reasonable sensitivity and specificity, appeared to be of less value as compared with the currently accepted antigen detection methodologies.
ABSTRACT:Plague surveillance is routinely conducted to predict future epizootics in wildlife and exposure risk for humans. The most common surveillance method for sylvatic plague is detection of antibodies to Yersinia pestis F1 capsular antigen in sentinel animals, such as coyotes (Canis latrans). Current serologic tests for Y. pestis, hemagglutination (HA) test and enzyme-linked immunosorbent assay (ELISA), are expensive and labor intensive. To address this need, we developed a complete lateral flow device for the detection of specific antibodies to Y. pestis F1 and V antigens. Our test detected anti-F1 and anti-V antibodies in serum and Nobuto filter paper samples from coyotes, and in serum samples from prairie dogs (Cynomys ludovicianus), lynx (Lynx canadensis), and black-footed ferrets (Mustela nigripes). Comparison of cassette results for anti-F1 and anti-V antibodies with results of ELISA or HA tests showed correlations ranging from 0.68 to 0.98. This device provides an affordable, user-friendly tool that may be useful in plague surveillance programs and as a research tool.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.