Protective efficacy of lambdacyhalothrin-impregnated bednets against Phlebotomus orientalis, the vector of visceral leishmaniasis in Sudan.

Field investigations on the sandfly Phlebotomus orientalis (Diptera: Psychodidae), the vector of Leishmania donovani causing visceral leishmaniasis (VL) in Sudan, were undertaken in two villages (Bellow and Elgamel) and Dinder National Park, to determine the protective value of bednets (polyester, 100 denier) impregnated with lambda-cyhalothrin 10 mg a.i./m2 pyrethroid insecticide. After exposure to treated netting for 30 s, P. orientalis females all died within 1 h. When field-tested in Acacia woodland, treated bednets provided complete protection from bites of the vector. Numbers of P. orientalis females landing on human collectors without bednets or using untreated bednets averaged 32.0 +/- 8.3 or 6.9 +/- 2.7 per man-night, respectively, whereas collectors using treated bednets experienced no sandfly bites during the same period (18.00-06.00 hours, 12 nights in June 1995). Socio-behavioural observations on the bed-time of people living in both study villages indicated that the use of impregnated bednets against P. orientalis would give more potential protection for women and children than for male adults. Overall the proportions of people and their durations of exposure to the risk of sandfly bites (i.e. after sunset until they went to bed) were 40% unprotected for< 1h, 50% for 1-2h and >10% for > or = 2h. Because visceral leishmaniasis in Sudan occurs mainly in children, the use of impregnated bednets (outdoors as well as indoors), and going to bed early could provide a high degree of personal protection against this zoonotic infection.

The role of cytokines in Henoch Schonlein purpura.

Serum levels of tumor necrosis factor (TNF) and interleukin(IL-1) were studied in 20 HSP patients, in the acute phase and after remission, by ELISA technique. Skin biopsies obtained during the acute phase both from a lesion and from unaffected skin, as well as during remission, were immunostained for TNF, IL-1, and IL-6. The mean age of the patients was 9.8 (5-13). Mean serum TNF levels during the acute phase and remission were 14.0 +/- 8.9 pg/ml, and 6.8 +/- 2.4 pg/ml, respectively (p < 0.05). Serum TNF levels in patients with renal involvement (18.8 +/- 10.2 pg/ml) were significantly higher than in those without (10.8 +/- 6.5 pg/ml) (p < 0.05). Serum levels of IL-1 in the acute phase and remission were undetectable. All specimens showed leukocytoclastic vasculitis. Immunohistochemical studies revealed TNF, and a less intense IL-1 and IL-6 staining in the nucleated epidermal layer, with a granular, intracellular pattern. Staining was significantly increased in the affected skin during the acute phase. These results suggest that TNF, IL-1, and IL-6 may play a role as a mediator of inflammation in HSP.