Background: Malaria is endemic in most parts of Afghanistan and insecticide-based vector control measures are central in controlling the disease. Insecticide resistance in the main malaria vector Anopheles stephensi from Afghanistan is increasing and attempts should be made to determine the underlying resistance mechanisms for its adequate management. Methods:The contents of cytochrome P450s, esterases, glutathione S-transferases (GSTs) and acetylcholine esterase (AChE) activities were measured in the Kunar and Nangarhar populations of An. stephensi from Afghanistan and the results were compared with those of the susceptible Beech strain using the World Health Organization approved biochemical assay methods for adult mosquitoes. Results:The cytochrome P450s enzyme ratios were 2.23-and 2.54-fold in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The enzyme ratios for esterases with alpha-naphthyl acetate were 1.45 and 2.11 and with beta-naphthyl acetate were 1.62 and 1.85 in the Kunar and Nangarhar populations respectively compared with the susceptible Beech strain. Esterase ratios with para-nitrophenyl acetate (pNPA) were 1.61 and 1.75 in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The GSTs enzyme ratios were 1.33 and 1.8 in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The inhibition of AChE was 70.9 in the susceptible Beech strain, and 56.7 and 51.5 in the Kunar and Nangarhar populations. The differences between all values of the enzymes activities/contents and AChE inhibition rates in the Kunar and Nangarhar populations were statistically significant when compared with those of the susceptible Beech strain. Conclusions:Based on the results, the reported resistance to pyrethroid and organophosphate insecticides, and tolerance to bendiocarb in the Kunar and Nangarhar populations of An. stephensi from Afghanistan are likely to be caused by a range of metabolic mechanisms, including esterases, P450s and GSTs combined with target site insensitivity in AChE.
Characteristics of mosquito larval habitats are important in determining whether they can survive and successfully complete their developmental stages. Therefore, data on the ecological factors affecting mosquito density and abundance especially the physicochemical properties of water of their breeding sites, can possibly be helpful in implementing larval management programs. Mosquito larvae were collected using a standard 350 ml dipper from fixed habitats including: artificial pool, river edge, creek and etc, in 30 villages of 16 counties from May-December 2014. Water samples were collected during larval collection and temperature (°C), acidity (pH), turbidity (NTU), electrical conductivity (μS/cm), alkalinity (mg/l CaCO3), total hardness (mg/l), nitrate (mg/l), chloride (mg/l), phosphate (mg/l) and sulphate (mg/l) were measured using standard methods. Spearman correlation coefficient, Kruskal-Wallis test of nonparametric analysis, Chi-square (χ2) analysis, regression analysis and C8 interspecific correlation coefficient were used for data analysis. A total of 7,566 mosquito larvae belonging to 15 species representing three genera were collected from fixed larval breeding places. Culex pipiens was the dominant species except in four villages where An. maculipennis s.l. and Cx. torrentium were predominant. There was a significant positive correlation between the density of Cx. pipiens and electrical conductivity, alkalinity, total hardness and chloride, whereas no significant negative correlation was observed between physicochemical factors and larval density. The highest interspecific association of up to 0.596 was observed between An. maculipennis s.l/An. pseudopictus followed by up to 0.435 between An. maculipennis s.l/An. hyrcanus and An. hyrcanus/An. pseudopictus. The correlations observed between physicochemical factors and larval density, can possibly confirm the effect of these parameters on the breeding activities of mosquitoes, and may be indicative of the presence of certain mosquito fauna in a given region.
Mosquitoes transmit a variety of diseases to humans. Their abundance and distribution are related to the characteristics of larval habitats. Mosquito larvae were collected from 120 natural and artificial habitats in 30 villages of 16 counties using standard 350 ml dippers and pipette, on a monthly basis from May-December 2014 in Mazandaran Province, northern Iran. Larval habitat characteristics were recorded separately, based on the conditions of the habitats (permanent or temporary, stagnant or running), type of habitats (natural or artificial), vegetation, exposure to sun, type of bed, water condition (clear or turbid), expanse (m), depth (cm, m) and temperature (°C) of habitats. The relationship between larval density and environmental variables was assessed by Chi-square tests. Totally, 19,840 larvae from three genera and 16 species were collected and identified. Anopheles maculipennis s.l. and Culex pipiens were the dominant species and collected with the highest density in plain areas. The highest number of larvae were collected from natural habitats (60.34%), including; river edge, marsh, pit and wetlands; with temporary and stagnant water, expanse of 0-5 m, depth of 1-25 cm, without plant, shadow-sun, muddy floor, turbid water, temperature 20-25°C and in sunny conditions. River edge and rice fields for An. maculipennis s.l and, wetlands and discarded tires for Cx. pipiens were the main larval habitats in the province. Statistical analysis revealed significant relation between occurrence of An. maculipennis s.l., Cx. pipiens, Culex torrentium, Culex mimeticus and Cs. annulata with each of the environmental variables (P < 0.001). These findings are essential in expanding our knowledge of the vectors ecology specially the type of habitat preference and will be beneficial in larval control programs.
Cockroaches are considered to be important reservoirs for protozoan and helminth parasites ,particularly an emerging Lophomonas spp., protozoan parasite. German cockroaches, Blattella germanica (B. germanica), are domestic pest distributed worldwide. However, little information is available regarding the burden of Lophomonas spp. infestation among domestic cockroach population worldwide. The present study investigated parasitic agents, emphasizing Lophomonas spp. infestation among B. germanica in northern Iran. During spring and summer 2018, a total of 496 adults B. germanica (265 males and 231 females) were trapped by hand and glass traps from the teaching hospitals in Mazandaran, Sari, northern Iran. All cockroaches were identi ed using taxonomic keys. Each cockroaches was anesthetized with chloroform and the alimentary tract removed. Each section was smeared onto a glass slide. All the smears were examined under light microscopy to determine the presence of the parasites. Ten genera of parasites were identi ed from the trapped B. germanica; overall, 233 (47%) were found to be positive for helminths (n=135) and protozoa (n=98). The helminths included Aspiculuris tetraptera egg ( 67/233, 28.7%), Oxiuros sp. (39/233; 16.7%), Dentostomella translucida (17/233; 7.3%), and nematodes Ova (12/233; 5.2%). The protozoan parasites identi ed Gregarina sp. (61/233; 26.2%), Entamoeba sp. (19/233; 8.2%), Blastocystis sp. (5/233; 2.1%), Lophomonas (4/233; 1.7%), Nyctotherus sp. (4/233; 1.7%), unclassi ed agella (5/233; 2.1%). Lophomonas spp. was detected within the gut of B. germanica, for the rst time, in Iran. It has previously been identi ed in the gut of cockroaches a long time ago, however, thisis the rst attempt to detect Lophomonas in cockroaches housing in hospitals. Thereby, it possibly presenting pose a serious respiratory infection risk for patients and health care personnel.
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