ABSTRACT
The German cockroach, Blattella germanica is a major hygienic pest and mechanical vector for pathogenic agents in hospitals and residential areas. The development of insecticide resistance is a serious problem in controlling of this pest. Toxicity of four commonly used insecticides [permethrin, cypermethrin, malathion and chlorpyrifos] against two hospital- collected strains of the German cockroach was investigated. Topical bioassay methods were carried out for detecting insecticide susceptibility of adult male cockroaches. For each insecticide, four to six concentrations resulting in >0% and <100% mortality were used. Three to six replicates of 10 cockroaches per concentration were conducted. The differences between LD[50] [microg/g] values were considered statistically significant only when the 95% confidence intervals did not overlap. Two hospital- collected strains of the German cockroach showed low to moderate levels of resistance to chlorpyrifos, permethrin, malathion and cypermethrin based on resistance ratios compared with susceptible strain. The low level chlorpyrifos resistance suggesting this insecticide may still provide adequate control of these strains. While the obsereved moderate levels of resistance to cypermethrin could imply developing resistance to this compound
ABSTRACT
OBJECTIVE@#To determine the variations in morphological characters of Culex pipiens complex and identify the species complex.@*METHODS@#A study was carried out from April to October 2009 in Yazd Province, Iran. This study was performed in two randomly selected rural villages in Yazd County using different sampling methods such as larval collection, hand catch, pyrethrum space spray, light trap, and pit shelter collections. The data were analyzed using SPSS software Ver. 16. ANOVA and Tukey's post-hoc test was used to compare the ratios of the samples.@*RESULTS@#The average of the DV/D ration was 0.090±0.007 and the range was 0-0.33. The average D/V ratio was 1.07±0.02, with maximum 1.6 and minimum 0.6. The costa and subcosta intersection were observed beyond the bifurcation of R2+3 in most of the specimens. The bifurcations of R2+3 and M1+3 veins were not on one direction in all samples. The range of the R-Cell/R2+3 ratio was 2.42-7.91. The average ratio of cross wing was 2.25±0.04 with a range of 1.36-3.70.@*CONCLUSIONS@#More populations of Culex pipiens from different areas of Iran need to be studied to gain complete information about the taxonomy and ecology of the species.
Subject(s)
Animals , Female , Male , Culex , Classification , Iran , Microscopy , PhylogeographyABSTRACT
Anthroponotic cutaneous leishmaniasis [ACL] has long been a significant public health problem in northeastern Iran. The objective of this study was to determine the efficacy of deltamethrin-impregnated vs. nonimpregnated bed nets [NIBs] and curtains [NICs] in ACL control. Deltamethrin-impregnated bed nets [IBs] and curtains [ICs] with 25 mg ai/m[2] were distributed among 160 households in one district and NIBs and NICs were distributed among the same number of households in another district. A third district with a similar numbers of households served as a control. Health education messages were disseminated to ensure the population's complicance with the proper use of bed nets and curtains. Sticky paper traps were used to assess the effect of insecticide-impregnated bed nets and curtains on the density of Phlebotomus sergenti. Deltamethrin susceptibility and also bioassay tests were carried out on the species by WHO standard method. Case findings were done by house-to-house visits once a season and all the inhabitants of the selected households in each district were examined. IBs and ICs provided good protection against sandfly bites and reduced the transmission of ACL in the intervention district, while NIBs and NICs provided no protection. There was no significant difference in monthly density of P. sergenti indoors and outdoors among the districts [P>0.05]. This species was susceptible to delta-methrin in the field population in the area. Bioassays confirmed that the nets treated with deltamethrin remained effective for more than 3 months. Personal protection is an effective and sustainable means of preventing and controlling ACL and can reduce dependence on insecticides. We encourage the use of IBs and ICs to control ACL in other high-risk areas of Iran and Afghanistan during the active season of sandflies