Evidence of metabolic mechanisms playing a role in multiple insecticides resistance in Anopheles stephensi populations from Afghanistan.

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

Global water quality changes posing threat of increasing infectious diseases, a case study on malaria vector Anopheles stephensi coping with the water pollutants using age-stage, two-sex life table method

Background: Water pollution due to uncontrolled release of chemical pollutants is an important global problem. Its effect on medically important insects, especially mosquitoes, is a critical issue in the epidemiology of mosquito-borne diseases. Methods: In order to understand the effect of water pollutants on the demography of Anopheles stephensi, colonies were reared in clean, moderately and highly polluted water for three consecutive generations at 27 °C, 75% RH, and a photoperiod of 12:12 h (L:D). The demographic data of the 4th generation of An. stephensi were collected and analysed using the age-stage, two-sex life table. Results: The intrinsic rate of increase (r), finite rate of increase (λ), mean fecundity (F) and net reproductive rate (R0) of An. stephensi in clean water were 0.2568 d−1, 1.2927 d−1, 251.72 eggs, and 109.08 offspring, respectively. These values were significantly higher than those obtained in moderately polluted water (r = 0.2302 d−1, λ = 1.2589 d−1, 196.04 eggs, and R0 = 65.35 offspring) and highly polluted water (r = 0.2282 d−1, λ = 1.2564 d−1, 182.45 eggs, and R0 = 62.03 offspring). Female adult longevity in moderately polluted (9.38 days) and highly polluted water (9.88 days) were significantly shorter than those reared in clean water (12.43 days), while no significant difference in the male adult longevity was observed among treatments. Conclusions: The results of this study showed that An. stephensi can partially adapt to water pollution and this may be sufficient to extend the range of mosquito-borne diseases

Kdr genotyping and the first report of V410L and V1016I kdr mutations in voltage-gated sodium channel gene in Aedes aegypti (Diptera: Culicidae) from Iran

Background: Aedes aegypti is the main vector of arboviral diseases worldwide. The species invaded and became established in southern Iran in 2020. Insecticide-based interventions are primarily used for its control. With insecticide resistance widespread, knowledge of resistance mechanisms is vital for informed deployment of insecticidal interventions, but information from Iranian Ae. aegypti is lacking. Methods: Fifty-six Ae. aegypti specimens were collected from the port city of Bandar Lengeh in Hormozgan Province in the South of Iran in 2020 and screened for kdr mutations. The most common kdr mutations in Latin America and Asia (V410L, S989P, V1016G/I and F1534C), especially when present in combinations, are highly predictive of DDT and pyrethroid resistance were detected. Phylogenetic analyses based on the diversity of S989P and V1016G/I mutations were undertaken to assess the phylogeography of these kdr mutations. Results: Genotyping all four kdr positions of V410L, S989P, V1016G/I and F1534C revealed that only 16 out of the 56 (28.57%) specimens were homozygous wild type for all kdr mutation sites. Six haplotypes including VSVF (0.537), VSVC (0.107), LSVF (0.016), LSIF (0.071), VPGC (0.257) and LPGC (0.011) were detected in this study. For the first time, 11 specimens harbouring the V410L mutation, and 8 samples with V1016I mutation were found. V410L and V1016I were coincided in 8 specimens. Also, six specimens contained 1016G/I double mutation which was not reported before. Conclusions: The relatively high frequency of these kdr mutations in Iranian Ae. aegypti indicates a population exhibiting substantial resistance to pyrethroid insecticides, which are used widely in control operations and household formulations. The detection of the 410L/1016I kdr mutant haplotype in Iranian Ae. aegypti suggests possible convergence of invasive populations from West Africa or Latin America. However, as Iran has very limited maritime/air connections with those African countries, a Latin American origin for the invasive Ae. aegypti in Iran is more plausible

Prevention and Control Policies of Dengue Vectors (Aedes aegypti and Aedes albopictus) in Iran

Background and Purpose: Dengue fever has become a major public health problem in many world regions due to increased trade, travel, and problems controlling Aedes vectors. This policy brief aims to review, analyze, and present evidence-based policies for dengue prevention and control. Materials and Methods: The present research is a compilation of a policy brief in Iran, carried out in 3 stages according to its methodology. In the first stage, the problem’s justification and description were provided systematically by examining scientific documents by searching national and international scientific databases, websites, guidelines, and books. In the second stage, the first author prepared a draft of the priority elements related to the policy framework and discussed them with other authors. In the third stage, the draft questions were categorized and summarized, and subsequently, the policies were compiled in close discussion with all authors. Results: According to the recommendations of the best available evidence in the literature, 5 policy options were presented for the prevention and control of dengue fever as follows: 1) developing basic, applied, and innovative research; 2) strengthening the capacity and capability of the human, infrastructural, and health system in all relevant sectors for the surveillance, control, monitoring, and evaluation; 3) strengthening inter- and intra-sectoral coordination and collaboration; 4) community engagement and mobilization; and 5) scaling up of functions and integrating tools.  Conclusion: To increase the long-term impact of policies, it is recommended to use an integrated approach with the continuous support of all stakeholders (local, national, and regional)

Purification and characterization of hemocyte phenoloxidases in Chilo suppressalis walker (Lepidoptera: Crambidae)

In the current study, two phenoloxidases (POs) from the larvae of Chilo suppressalis Walker were extracted and purified by column chromatography using Sepharyl G-100 and DEAE-Cellulose fast flow column. Two proteins possessing PO activity, named as POI and POII, were extracted by purification, 5.08- and 5.62-fold, respectively, with 8.94% and 7.31% recoveries, respectively. Also, the specific activities of POI and POII were 0.478 and 0.529 U/mg protein, respectively. Finally, the molecular weights of POI and POII were calculated as 94.6 and 95.7 kDa, respectively. Kinetic parameters of the purified phenoloxidases by Lineweaver-Burk analysis were Vmax of 2.27 and 1.11 U/mg protein and Km of 15.51 and 17.31 mM for POI and POII, respectively. Mg2+ and Cu2+ significantly increased the PO activities. Ca2+ decreased the activity of POI and showed no statistical effects on POII activity. EDTA and DTC significantly inhibited the activities of the purified enzymes, while triethylenetetramine hexaacetic acid (TTHA) and RGTA showed no significant effects on enzymatic activities

Screening and Virulence of the Entomopathogenic Fungi Associated with <i>Chilo suppressalis</i> Walker

The current study aimed to explore the entomopathogenic fungi associated with the larvae of Chilo suppressalis Walker, a serious pest of rice, in northern Iran. The collected specimens were cultured and identified through morphological and molecular methods. The 38 specimens were identified by microscopic examination and genetic sequencing of the ITS region as follows: twenty-one isolates of Beauveria bassiana, five isolates of Akanthomyces lecanii, four isolates of Akanthomyces muscarious, three isolates of Metarhizium anisopliae, two isolates of Hirsutella subulata, two isolates of Trichoderma sp. and one isolate of Aspergillus sp. All the identified isolates were treated on the larvae through bioassay, evaluating the amount of hydrophobin and the activities of proteases, chitinases and lipase to find their virulence. Moreover, the percentage of thermotolerant and cold activity of the isolates were tested to determine their environmental persistence. The overall results revealed the isolates of B. bassiana, including BBRR1, BBAL1 and BBLN1 as the most virulent and environmental adaptive isolates among the fungi associated with C. suppressalis

Entomological Surveillance of the Invasive Aedes Species at Higher-Priority Entry Points in Northern Iran: Exploratory Report on a Field Study

BackgroundArboviral diseases such as dengue, Zika, and chikungunya are transmitted by Aedes aegypti and Ae albopictus and are emerging global public health concerns. ObjectiveThis study aimed to provide up-to-date data on the occurrence of the invasive Aedes species in a given area as this is essential for planning and implementing timely control strategies. MethodsEntomological surveillance was planned and carried out monthly from May 2018 to December 2019 at higher-priority entry points in Guilan Province, Northern Iran, using ovitraps, larval collection, and human-baited traps. Species richness (R), Simpson (D), evenness (E), and Shannon-Wiener indexes (H̕) were measured to better understand the diversity of the Aedes species. The Spearman correlation coefficient and regression models were used for data analysis. ResultsWe collected a total of 3964 mosquito samples including 17.20% (682/3964) belonging to the Aedes species, from 3 genera and 13 species, and morphologically identified them from May 2018 to December 2019. Ae vexans and Ae geniculatus, which showed a peak in activity levels and population in October (226/564, 40.07% and 26/103, 25.2%), were the eudominant species (D=75.7%; D=21.2%) with constant (C=100) and frequent (C=66.7%) distributions, respectively. The population of Ae vexans had a significant positive correlation with precipitation (r=0.521; P=.009) and relative humidity (r=0.510; P=.01), whereas it was inversely associated with temperature (r=−0.432; P=.04). The Shannon-Wiener Index was up to 0.84 and 1.04 in the city of Rasht and in July, respectively. The rarefaction curve showed sufficiency in sampling efforts by reaching the asymptotic line at all spatial and temporal scales, except in Rasht and in October. ConclusionsAlthough no specimens of the Ae aegypti and Ae albopictus species were collected, this surveillance provides a better understanding of the native Aedes species in the northern regions of Iran. These data will assist the health system in future arbovirus research, and in the implementation of effective vector control and prevention strategies, should Ae aegypti and Ae albopictus be found in the province

Biodiversity Species and Ecological Distribution of Scorpions in the City of Darmian, Southern Khorasan, Iran

Background and purpose: Scorpionism is a public health problem in Darmian City.  This study was conducted to determine the biodiversity and faunistic of scorpions in order to discover the health preventive features of scorpion sting among the residents of these regions. Methods: A nightly and daily actively searching on distribution and biodiversity of scorpions was carried during April 2015 to March 2016 in Darmian, Iran. Results: A total of 685 scorpions including five species belonging to buthidae family were identified. The highest abundance was observed in warmer months, and Mesobuthus eupeus (54.5%) was the most abundant species. The researchers found a positive correlation between abundance and temperature and a negative correlation between abundance and humidity. The scorpions were observed with more nocturnal activity and were well-adapted with more abundance to the plain, rural, and outdoors environments. Regarding constancy index, all species except A. crassicauda were classified as constant species (C=100). There was no significant difference in the richness of scorpions in different time collections (day or night), geographical areas (plain or mountainous), regions collected (urban or rural), and places (indoors or outdoors). The Shannon and dominant indices were found to be not significantly different between mentioned sites except in time collection. Conclusions: Species composition of scorpions revealed that scorpions were constantly active throughout the year which can play an important role in sting events. So, familiarity of healthcare experts and indigenous people with existing species and their seasonal activities can largely reduce the risk of scorpion stings

Designing and Determining the Validity and Reliability of a Questionnaire to Assess Knowledge, Attitude, and Practice of Healthcare Workers about Dengue in Mazandaran Province, North of Iran

Background and purpose: The knowledge, attitude, and practice (KAP) of healthcare workers are important to reduce the transmission and burden of dengue. There is no standard tool to assess KAP of healthcare workers about dengue in Mazandaran Province, Iran, so this study was conducted to design and assess the validity and reliability of a questionnaire in Persian assessing KAP of healthcare workers about these mosquito-borne viral disease. Materials and methods: In this descriptive analytical study, a preliminary questionnaire containing 81 questions was designed after reviewing articles and interviews with experts. To determine the validity of the scale, quantitative-qualitative face and content validity were measured, and Cronbach's alpha coefficient was used to assess the reliability. Results: In the study of face validity and qualitative content, experts' opinions were applied to the items as minor changes. The Impact Score (IS) of all items were higher than 1.5 (1.5-5) which provided supports for items importance. Content validity, based on the Lawshe table, optimal value of content validity ratio (CVR), and content validity index (CVI) were 0.6 and higher than 0.8, respectively. All items except one that was removed, obtained the desired score and were retained in the scale. Cronbach's alpha coefficient was 0.79 which showed that all items had an acceptable correlation. Conclusion: This study provided a reliable and valid tool in Persian to assess KAP of healthcare workers about dengue in Mazandaran Province, north of Iran and can be used for measuring dengue KAP by Iranian researchers

A Comparison of Therapeutic and Anti-inflammatory Properties of Triamcinolone and Placebo (Vitamin A) in Treatment of Paederus Dermatitis

Abstract Background and purpose: Paederus associated dermatitis has always been considered as a health problem in the northern of Iran. Since until now, the traditional method and some corticosteroids have been used in the treatment of Paederus dermatitis (PD) and no comprehensive studies have been carried out on the new method of treatment. Therefore, this study was aimed to compare the anti-inflammatory effects of triamcinolone with placebo in treatment of PD. Materials and Methods: This randomized double-blind clinical trial was performed during 6 months period in the clinics of Sari and Neka, Iran. Experimental group received triamcinolone and control group received placebo. The therapeutic effects of topically applied triamcinolone in 15 dermatitis patients and 15 control subjects were compared. The study subjects were visited in three separate times in the 1st, 7th and 14th day of the treatment. The data were collected in the questionnaire and compared in both groups by introducing the data into SPSS 11 software and analyzed by means of &chi; 2 test. Results: A total of 15 patients, 10 and 5 cases were undertaken for treatment in the Sari and Neka Townships, respectively. 40% and 50% of the patients from Sari and Neka Townships had lesion size 6-10 cm2, respectively. In this study, 90% and 100% of the patients from Sari and Neka had complete recovery 7 days after treatment, respectively. Statistical analysis indicated a significant difference between the case and control groups (P < 0.05). Conclusion: Insignificant difference was observed for treatment between the patients from the two Townships under study