Symptomatic malaria diagnosis overestimate malaria prevalence, but underestimate anaemia burdens in children: results of a follow up study in Kenya.

BACKGROUND: The commonly accepted gold standard diagnostic method for detecting malaria is a microscopic reading of Giemsa-stained blood films. However, symptomatic diagnosis remains the basis of therapeutic care for the majority of febrile patients in malaria endemic areas. This study aims to compare the discrepancy in malaria and anaemia burdens between symptomatic diagnosed patients with those diagnosed through the laboratory. METHODS: Data were collected from Western Kenya during a follow-up study of 887 children with suspected cases of malaria visiting the health facilities. In the laboratory, blood samples were analysed for malaria parasite and haemoglobin levels. Differences in malaria prevalence between symptomatic diagnosis and laboratory diagnosis were analysed by Chi-square test. Bayesian probabilities were used for the approximation of the malaria and anaemia burdens. Regression analysis was applied to: (1) determine the relationships between haemoglobin levels, and malaria parasite density and (2) relate the prevalence of anaemia and the prevalence of malaria. RESULTS: The prevalence of malaria and anaemia ranged from 10% to 34%, being highest during the rainy seasons. The predominant malaria parasite was P. falciparum (92.3%), which occurred in higher density in children aged 2‒5 years. Fever, high temperature, sweating, shivering, vomiting and severe headache symptoms were associated with malaria during presumptive diagnosis. After conducting laboratory diagnosis, lower malaria prevalence was reported among the presumptively diagnosed patients. Surprisingly, there were no attempts to detect anaemia in the same cohort. There was a significant negative correlation between Hb levels and parasite density. We also found a positive correlation between the prevalence of anaemia and the prevalence of malaria after laboratory diagnosis indicating possible co-occurrence of malaria and anaemia. CONCLUSION: Symptomatic diagnosis of malaria overestimates malaria prevalence, but underestimates the anaemia burden in children. Good clinical practice dictates that a laboratory should confirm the presence of parasites for all suspected cases of malaria.

Experimental chemotherapy with Allium sativum (Liliaceae) methanolic extract in rodents infected with Leishmania major and Leishmania donovani.

BACKGROUND & OBJECTIVES: Several plant products have been tested and found to possess antileishmanial activity. The present study was undertaken to establish whether methanolic extract of Allium sativum Linn has antileishmanial activity in comparison to standard drugs. METHODS: Methanolic extract of A. sativum bulbs was screened for in vitro and in vivo antileishmanial activity against Leishmania major strain (NLB 145) and L. donovani strain (NLB 065). Pentostam and Amphotericin B were used as standard drugs. BALB/c mice and golden hamsters (Mesocricetus auratus) were used in in vivo studies on L. major and L. donovani respectively. RESULTS: The extract exhibited very low cytotoxicity (IC50 >450 µg/ml) against Vero cells. The extract had significantly better (p <0.001) leishmanicidal activity against both species (IC50 34.22 µg/ml to L. major, 37.41 µg/ml to L. donovani) than Pentostam. However, the activity was significantly lower (p <0.001) than that of Amphotericin B against both the species. At a concentration of 250 µg/ml, the extract induced the production of 60 µM of nitric oxide, a ten-fold up-regulation in activated macrophages. The multiplication indices for L. major amastigotes treated in 100 µg/ml were significantly different (p <0.05). Treatment with the extract, daily for 28 days led to a significant reduction (p <0.05) in footpad swelling in BALB/c mice; similar activity noticed in the treatment with standard drugs. The Leishman-Donovan Units (LDU) for the extract treated animals were significantly higher (p <0.05) than those of standard drugs, but lower compared to the negative control. INTERPRETATION & CONCLUSION: Since the mechanism of action for the methanolic extract is apparently immunomodulatory, garlic compounds could be purified and tried as complementary medicine in the management of leishmaniases.

Antimalarial Activity of Croton macrostachyus Stem Bark Extracts against Plasmodium berghei In Vivo.

There is an increasing need for innovative drug and prophylaxis discovery against malaria. The aim of the present study was to test in vivo antiplasmodial activity of Croton macrostachyus H. (Euphorbiaceae) stem bark extracts from Kenyan folkloric medicine. Inbred Balb/c mice were inoculated with erythrocytes parasitized with Plasmodium berghei (ANKA). Different doses (500, 250, and 100 mg/kg) of C. macrostachyus ethyl acetate, methanol, aqueous, and isobutanol extracts were administrated either after inoculation (Peters' 4-day suppressive test) or before inoculation (chemoprotective test) of the parasitized erythrocytes. All the extracts showed significant suppression of parasitemia compared to control (p < 0.001): for the ethyl acetate extract in the range of 58-82%, for the methanol extract in the range of 27-68%, for the aqueous extract in the range of 24-72%, and for the isobutanol extract in the range of 61-80%. Chemoprotective effect was significant (p < 0.001) and the suppression caused by the ethyl acetate extract was between 74 and 100%, by the methanol extract between 57 and 83%, and by the isobutanol extract between 86-92%. The study showed that it is possible to inhibit the growth of the parasites by various stem bark extracts of C. macrostachyus in Balb/c mice supporting the folkloric use of the plant against malaria.