Determining the burden of neurological disorders in populations living in tropical areas: who would be questioned? Lessons from a Mexican rural community.

BACKGROUND: The best approach to determine the burden of neurological disorders in developing countries is to perform population-based studies. Our objectives were to determine the prevalence of neurological disorders in a Mexican rural community and assess the usefulness of a household screening questionnaire. METHODS: The survey took place in a Mexican rural community of Puebla State in Mexico. This was a cross-sectional, population-based, 2-phase study including a comparison of the usefulness levels of the individual (IQ) and household (HQ) questionnaires. RESULTS: A total of 4,008 individuals participated in the prevalence study using the IQ; of these, 280 neurological examinations allowed to identify 127 individuals suffering from at least 1 neurological disease. The most frequent ailments were headache (22.4/1,000, 95% confidence interval, CI: 17.7-28.2), neuropathy (7.1/1,000, CI 95%: 4.4-11.3) and epilepsy (3.9/1,000, CI 95%: 2.3-6.5). The HQ, used in parallel with the IQ, detected significantly fewer neurological cases. This result was mainly due to the low capacity of the HQ to detect headache. CONCLUSIONS: Results of the prevalence study are discussed emphasizing their relevance in adequately allocating resources. The usefulness of the HQ for screening neurological disorders in general was low, but could be adequate for specific neurological disorders.

Fungus-elicited metabolites from plants as an enriched source for new leishmanicidal agents: antifungal phenyl-phenalenone phytoalexins from the banana plant (Musa acuminata) target mitochondria of Leishmania donovani promastigotes.

Two antifungal phenyl-phenalenone phytoalexins isolated from the banana plant (Musa acuminata) elicited with the fungus Fusarium oxysporum, together with a methoxy derivative of one of them and two epoxide precursors of their chemical synthesis, were tested for leishmanicidal activity on Leishmania donovani promastigotes and L. infantum amastigotes. Drugs inhibited proliferation of both forms of the parasite with a 50% lethal concentration range between 10.3 and 68.7 micro g/ml. Their lethal mechanism was found linked to the respiratory chain by a systematic approach, including electron microscopy, measurement of the oxygen consumption rate on digitonin-permeabilized promastigotes, and enzymatic assays on a mitochondrial enriched fraction. Whereas the whole set of compounds inhibited the activity of fumarate reductase in the mitochondrial fraction (50% effective concentration [EC(50)] between 33.3 and 78.8 micro g/ml) and on purified enzyme (EC(50) = 53.3 to 115 micro g/ml), inhibition for succinate dehydrogenase was only observed for the two phytoalexins with the highest leishmanicidal activity: anigorufone and its natural analogue 2-methoxy-9-phenyl-phenalen-1-one (EC(50) = 33.5 and 59.6 micro g/ml, respectively). These results provided a new structural motif, phenyl-phenalenone, as a new lead for leishmanicidal activity, and support the use of plant extracts enriched in antifungal phytoalexins, synthesized under fungal challenge, as a more rational and effective strategy to screen for new plant leishmanicidal drugs.