Trypanosoma evansi Infections: Towards Penside Diagnosis

抄録

The mainstay for control of Trypanosoma evansi infections (surra) is chemotherapy and chemoprophylaxis. This strategy rests not only on availability of simple, efficacious drugs, but also on diagnosis. The parasitological techniques frequently employed in diagnosis, however, have very low sensitivity since most infections in the field are not associated with patent parasitaemia. An indirect latex agglutination test, Suratex®, for detecting circulating trypanosomal antigens in the blood of infected animals has the potential to circumvent this problem. The test is simple and rapid. It is carried out by mixing equal volumes of serum, plasma or whole blood with the Suratex® reagent on a test card, and the card rocked manually. ln positive reactions, agglutination develops in 2 minutes. Suratex® has been shown to be specific, with a specificity value of 99%, based on studies carried out using sera from horses, camels and cattle from non-endemic areas. The sensitivity of Suratex® is high: 93-97% of blood samples from animals with parasitologically confirmed diagnosis give positive reactions, and most importantly, the test also diagnoses the latent infections which cannot be detected by the parasitological techniques.