Background
Chemical control has been the most efficient method in mosquito control, the development of insecticide resistance in target populations has a significant impact on vector control. The use of agricultural pesticides may have a profound impact on the development of resistance in the field populations of malaria vectors. Our study focused on insecticide resistance and knockdown resistance (kdr) of Anopheles arabiensis populations from Northern Sudan, related to agricultural pesticide usage.
Results
Anopheles arabiensis from urban and rural localities (Merowe and Al-hamadab) were fully susceptible to bendiocarb 0.1% and permethrin 0.75% insecticides while resistant to DDT 4% and malathion 5%. The population of laboratory reference colony F189 from Dongola showed a mortality of 91% to DDT (4%) and fully susceptible to others. GLM analysis indicated that insecticides, sites, site type, and their interaction were determinant factors on mortality rates (P < 0.01). Except for malathion, mortality rates of all insecticides were not significant (P > 0.05) according to sites. Mortality rates of malathion and DDT were varied significantly (P < 0.0001 and P < 0.05 respectively) by site types, while mortality rates of bendiocarb and permethrin were not significant (P >0.05). The West African kdr mutation (L1014F) was found in urban and rural sites. Even though, the low-moderate frequency of kdr (L1014F) mutation was observed. The findings presented here for An. arabiensis showed no correlation between the resistant phenotype as ascertained by bioassay and the presence of the kdr mutation, with all individuals tested except the Merowe site which showed a moderate association with DDT (OR= 6 in allelic test), suggesting that kdr genotype would be a poor indicator of phenotypic resistance.
Conclusion
The results provide critical pieces of information regarding the insecticide susceptibility status of An. arabiensis in northern Sudan. The usage of the same pesticides in agricultural areas seemed to affect the Anopheles susceptibility when they are exposed to those insecticides in the field. The kdr mutation might have a less role than normally expected in pyrethroids resistance; however, other resistance genes should be in focus. These pieces of information will help to improve the surveillance system and The implication of different vector control programs employing any of these insecticides either in the treatment of bed nets or for indoor residual spraying would achieve satisfactory success rates.
Geohelminthes are soil transmitted parasites and a major public health challenge in children, particularly in the tropical and subtropical regions of the world where sanitary conditions are poor. A study to determine the prevalence of geohelminthes infections among school children in parts of Lokoja Local Government Area of Kogi State was carried out. Stool specimens were collected from 254 school children in two primary schools and examined using standard concentration method. School children were randomly selected for the study. The overall prevalence of geohelminthes recorded was 58.30%. Five Geohelminthes were observed in order of prevalence; Fasciola spp (33.10%), Trichiuris trichiura (24.30%), Ascaris lumbricoides (21.60%), Hookworm (18.20%) and Enterobius vermicularis (2.70%). The prevalence rate in males was higher (37.80%) than that of the females (20.50%) and statistics significantly different (χ 2 = 3.841, p<0.05). The public school showed the highest infection rate (73.60%), while the private school assumed the least prevalence of (42.40%). Chi-square analysis showed a significant difference in the infection among the schools (χ 2 = 3.841, p<0.05). Based on these findings, mass treatment of school children, health education campaign, improved sanitary condition, provision of toilet facilities and personal hygiene were recommended as control and prevention measures.
Owing to the adverse effect of synthetic pesticides, there has been increasing need to search for natural and environment friendly pesticides of plant origin as agents for control of vector of mosquito-borne diseases. This study was aimed to investigate the larvicidal activities of North eastern botanicals against vector of mosquitoes-borne diseases. Five mosquito repellent plants used by the indigenous people of north eastern, Nigeria were analysed for their effectiveness against Anopheline mosquitoes. The methanol and petroleum ether were analysed for their phytochemical properties. The methanol and petroleum ether extracts were investigated for phytochemical compounds with larvicidal activities against anopheline 3rd instar larvae through using deferent extracts of methanol and petroleum ether of different concentration that ranged from 50-200 ppm. The larvicidal were observed after every six hours for total period of 36 hours. The extracts of Hyptis suaveolens and Azadirachta indica of both methanol and petroleum ether extracts showed high toxicity effects against anopheline. The test plants contained phenol, alkaloids, flavonoids, tannins, azadrachtin, glycosides saponins, terpenoids and steroids.
In conclusion, the present plant extracts have potentials for development of new and safe control products for mosquitoes. As natural occurring insecticides, these plants derived materials that could be useful as an alternative for synthetic insecticides.
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