A simple and economical direct agglutination test for the detection of visceral leishmaniasis is described. Trypsin-treated, Coomassie Brilliant Blue-stained, formalin-preserved promastigotes were used as antigen in re-usable V-well microtitre plates. In 21 patients with recent kala-azar, titres of 1:51200 or higher were found. Cured kala-azar patients treated 4 to 14 months before testing, showed titres in the range of 1:3,200 to greater than 1:51,200. Healthy and diseased controls had titres below 1:1,600 with the exception of African trypanosomiasis patients who showed titres of 1:200 to 1:12,800, overlapping with the titres of cured kala-azar patients. Where trypanosomiasis is not a consideration, a titre of 1:1,600 could be considered indicative of visceral leishmaniasis, the sensitivity and specificity were then 100%. The test was applied to sera of 280 inhabitants of Baringo District, a known focus of visceral leishmaniasis in Kenya. When treated cases were included, the test showed a sensitivity of 100% and specificity of 99.3%. This test could be used in district hospitals and health centres in endemic areas as an aid in diagnosis of kala-azar and in the field for sero-epidemiological studies.

To increase the potential for the wide-scale application of our direct agglutination test for visceral leishmaniasis, modifications in the components and procedures were introduced. Supplementation with 0.056 M citrate of the suspension medium stabilized the antigen for 9 weeks at 3rC. To circumvent the need for cooling systems in the field, 0.2% (wt/vol) gelatin was added to the serum diluent instead of fetal bovine serum, with reliable results. Specificity and sensitivity were improved by the incorporation of 0.1 M 2-mercaptoethanol in samples with borderline titers. The test could be performed on samples of whole blood; thus the difficulties of preparation and storage of serum, plasma, or filter paper blood are avoided. For mass screening programs, a single serum dilution of 1:6,400 could be employed, contributing to a further reduction in test expenses. Sera from different geographical areas showed equal reactivities in this direct agglutination test despite the nonhomologous Leishmania donovani antigens used.

A newly developed direct agglutination test (DAT) for visceral leishmaniasis, IFAT and ELISA were applied to sera of patients with visceral leishmaniasis, African and American trypanosomiasis, other parasitic infections and healthy controls. The sensitivities of the 3 tests were comparable (96.3% to 100%); excluding patients with African and American trypanosomiasis, the specificities of DAT and IFAT were 100% and ELISA 87.3%. When trypanosomiasis sera were included, the specificities were 72.6%, 94.3% and 79.4% in DAT, IFAT and ELISA respectively. In 273 sera from a leishmaniasis endemic area (Baringo District, Kenya), the sensitivity was 80% in DAT and IFAT and 60% in ELISA, specificities being 99.6% (DAT), 98.5% (IFAT) and 62.5% (ELISA). As the new DAT is economical and easy to perform, it is recommended for sero-epidemiological field work on visceral leishmaniasis.

The efficacy of an oral 8-aminoquinoline (8-[[6-(diethylamino)hexyl]amino]-6-methoxy-4-methylquinoline) (WR6026) in the treatment of 16 patients with kala azar was evaluated. The first 8 patients received therapy for 2 weeks at a dosage of 0.75-1.00 mg/(kg.d); 1 patient was cured, and in regard to the other 7, a 1-logarithm decrease in the number of splenic parasites and clinical improvement were noted. The next 8 patients received therapy for 4 weeks at the same daily dosage (1 mg/[kg.d]); 4 were cured, and for the other 4, 1- to 2-log decreases in the number of parasites and clinical improvement (in regard to weight, liver and spleen size, hemoglobin level, and leukocyte count) were noted. The therapy was associated with minimal toxicity; adverse effects included gastrointestinal distress, headache, and methemoglobinemia. The fact that one-half of the patients were cured indicates that future trials with longer regimens and higher dosages are warranted and should include patients for whom existing treatment methods have failed.