16 research outputs found
The direct agglutination test for diagnosis of visceral leishmaniasis under field conditions in Sudan: comparison of aqueous and freeze-dried antigens
Population relationships of Simulium yahense and Simulium sanctipauli in the Firestone Rubber Plantation at Harbel, Liberia
Resistance to insecticides in the SIMULIUM DAMNOSUM complex. Operational consequences. Development of new chemicals and formulations
Cytotaxonomic confirmation of two forms of Simulium sirbanum in the eastern part of the Onchocerciasis Control Programme in West Africa
The direct agglutination test for diagnosis of visceral leishmaniasis under field conditions in Sudan: comparison of qeqeous and freeze-dried antigens
The performance of the direct agglutination test (DAT) was evaluated under field conditions in an endemic area of visceral leishmaniasis in eastern Sudan, using aqueous (Aq) antigen which has to be kept refrigerated and a newly developed freeze-dried (FD) antigen which is stable at ambient temperature. Both antigens compared well, with 92-98% of readings being identical or only with one dilution difference in titre. FD antigen gave titres that were identical with Aq antigen in 73% of samples, higher in 19%, and lower in 8%. Owing to high ambient temperatures and low humidity, microtitre plate wells dried out during the standard procedures for elution and incubation. However, shortening the elution time from 12 to 4 h proved possible for both antigens; incubation could be reduced from 24 to 10 h for Aq antigen, after which the plates could still be read. Incubation with FD antigen required 18 h and the plates needed to be kept cool because of evaporation. Despite the longer procedure with the FD antigen, the DAT can be completed in 24 h and the use of this stable antigen, that does not require refrigeration, is a major improvement in performing the DAT under unfavourable field condition