ABSTRACT
@#Leishmaniasis causes significant morbidity and mortality worldwide. In our country, there has been a significant increase in the number of cases of leishmaniasis in the last decade. In our study, the effects of Hypericum thymbrifolium, Hypericum scabrum and Eryngium creticum plant extracts were tested on Leishmania major, Leishmania tropica and Leishmania infantum/donovani, which were clinically resistant by not responding to Glucantime® therapy. Cytotoxicity of these extracts were evaluated by XTT method in the human fibroblast cell line. Possible active ingredients were detected by GC-MS analysis from plant extracts. Glucantime® resistance was detected at concentrations of 50 µg/mL and lower in 4 of the 7 strains tested. No living leishmania parasites were found in leishmania strains treated with plant extracts at concentrations of 100 µg/mL or higher. The concentrations of plant extracts included in the study on the WI-38 human fibroblast cell line were not cytotoxic. According to the GC-MS analysis, several active substances with biological activities and anti-parasitic effects, such as Thiophene, Germacrene-D, trans-Geranylgeraniol, Pyridine, and Maleimides, were identified. Based on the findings of the study, it is believed that these identified active substances when supported by in-vivo studies, will pave the way for future research and have the potential to be developed as anti-leishmania drugs.
ABSTRACT
Insecticide treated bednets locate a deposit of a quick-acting insecticide of low human toxicity between a sleeper and host-seeking mosquitoes. Thus a chemical barrier is added to the often incomplete physical barrier provided by the net. Treated nets may be considered as mosquito traps baited by the odour of the sleeper. Trials in Assam, Tanzania and elsewhere have shown that when a whole community is provided with treated nets, so many mosquitoes of anthropophilic species are killed by contact with the nets that the density and/or sporozoite rate of the vector population is reduced. In order to gain this "mass" or community effect, in addition to widespread personal protection, and thus to achieve the full potential of the treated net method, a high per cent coverage of the community is needed. This suggests that organised free provision of treated nets, comparable to a house spraying programme, is likely to be more cost-effective than trying to market nets and insecticide to very poor rural people. In areas with high malaria transmission, where acquisition of immunity to malaria is very important, it has been argued that vector control (without vector eradication) could, in the long run, make the situation worse by preventing the normal build-up of immunity. However, our data from Tanzania do not support this idea--3-4 years after provision of nets (which are re-treated annually) young children are still showing clear health benefits; older children are not "paying" for this by showing worse impact of malaria. There is less malaria morbidity in a highland area where malaria transmission is about 15x less intense than in a nearby lowland area. The per cent impact of treated nets malaria morbidity in both area was very similar. At present only pyrethroids are used for net treatment which suggested that emergence of pyrethroid resistance would have a disastrous effect. However, in West Africa, where there is now a high frequency of the kdr resistance gene in Anopheles gambiae, it is reported that treated nets continue to have a powerful impact on vector populations. In Tanzania, pyrethroid resistance has not been detected in malaria vectors, but it has emerged in bedbugs after seven years use of treated nets.