Leishmaniasis in Sudan. 3. Visceral leishmaniasis

摘要: From the early 1900s, visceral leishmaniasis (VL; kala-azar) has been among most important health problems in Sudan, particularly main endemic area eastern and central regions. Several major epidemics have occurred, recent--in Western Upper Nile province southern detected 1988--claiming over 100,000 lives. The disease spread to other areas that were previously not known be for VL. A upsurge number of cases was noted area. These events triggered renewed interest disease. Epidemiological entomological studies confirmed Phlebotomus orientalis as vector several parts country, typically associated with Acacia seyal Balanites aegyptiaca vegetation. Infection rates Leishmania high, but subject seasonal variation, numbers sand flies. Parasites isolated from humans flies belonged three zymodemes (MON-18, MON-30 MON-82), which all belong L. donovani sensu lato cluster. Transmission dynamics elucidated fully; heavy transmission relatively scarcely populated such Dinder national park suggested zoonotic whereas large patients post kala-azar dermal (PKDL) heavily affected villages may indicate a human reservoir anthroponotic transmission. Clinical presentation adults children did differ significantly, except more anaemic. Fever, weight loss, hepato-splenomegaly lymphadenopathy common findings. PKDL much than expected (56% VL developed PKDL), post-VL manifestations also found affecting eyes (uveitis, conjunctivitis, blepharitis), nasal and/or oral mucosa. Evaluation diagnostic methods showed parasitological diagnosis should still mainstay diagnosis, sensitivities lymph node, bone marrow spleen aspirates 58%, 70% 96%, respectively. Simple, cheap serological tests are needed. direct agglutination test (DAT) had sensitivity 72%, specificity 94%, positive predictive value 78% negative 92%. As tests, DAT cannot distinguish between active disease, subclinical infection or past infection. introduction freeze-dried antigen control sera greatly improved practicality accuracy field. An enzyme-linked immunosorbent assay using recombinant K39 higher (93%). polymerase chain reaction peripheral blood gave 70-93% sensitive microscopy node suspected leishmanin skin (LST) during converted c. 80% 6 months after treatment. Immunological both Th1 Th2 cell responses could demonstrated nodes evidenced by presence messenger ribonucleic acid interleukin (IL)-10, interferon gamma IL-2. Treatment mononuclear cells IL-12 drive immune response toward type production gamma, indicating potential therapeutic role IL-12. responded well treatment sodium stibogluconate, is first line drug at dose 20 mg/kg intravenously intramuscularly per day 15-30 d. Side effects resistance rare. Liposomal amphotericin B effective, few side effects. Control measures implemented. Based on observations does occur individuals who LST, probably because previous cutaneous leishmaniasis, vaccine containing heat-killed promastigotes currently undergoing phase III trial.