Development and evaluation of a rapid diagnostic immunochromatographic device to detect antibodies in sera from intestinal capillariasis cases

Intestinal capillariasis, a fish-borne nematodiasis, is an important emerging zoonotic disease. Patients present clinical symptoms of borborygmus chronic diarrhea, intermittent abdominal pain, weight loss, and several degrees of painless lower-leg edema. Death may occur in cases of misdiagnosis and improper treatment. Diagnosis is difficult because of the atypical clinical symptoms and diagnostic confusion with diarrhea caused by gastrointestinal cancer, opportunistic infections in human immunodeficiency virus patients, and hyperthyroidism. In addition, parasite eggs are not always found in stool examination. Serology can provide a supportive diagnostic tool. We have produced a rapid and simple immunochromatographic test (ICT) kit for diagnosis of intestinal capillariasis by detection of diagnostic antibodies in human sera. Serum samples from healthy volunteers and patients with proven intestinal capillariasis and other parasitic diseases were evaluated with the Trichinella spiralis larval extract antigen absorbed ICT strips. The diagnostic sensitivity, specificity, and positive and negative predictive values were 100, 96.6, 90.2, and 100%, respectively. The ICT kit is simple and rapid to use and can supplement stool examination in clinical diagnosis of intestinal capillariasis. The test can be completed in 15 min without a need for any sophisticated instruments or reagents.