Vol 13 No 4 (2019)

Published: 2020-01-01

Review Article

  • XML | PDF | downloads: 277 | views: 208 | pages: 344-352
    Background: Malaria is the main vector–borne disease worldwide. There are several reports of insecticide resistant in malaria vectors worldwide due to using different insecticides. The aim of this study was to evaluate different native plant extortions against main malaria vector, Anopheles stephensi in Iran for choosing the appropriate plant for formula­tion and use for vector control.Methods: The larvae of An. stephensi were reared in insectary, extraction of plants were carried out at department of Pharmacology. The standard WHO method for biological tests was used for calculation of LC50 and LC90. Probit regra­tion lines were plotted for calculation of LC50 and LC90.Results: In this study several plants including: Mentha spicata, Cymbopogon olivieri, Azadirachta indica, Melia azeda­rach, Lagetes minuta, Calotropis procera, Eucalyptus camaldulensis, Cupressus arizonica, Thymus vulgaris, Lawsonia inermis, Cedrus deodara, Cionura erecta, Bunium persicum, Carum carvi, Artemisia dracunculus, Rosmarinus offici­nalis were used. Results showed that Mentha spicata and Eucalyptus camaldulensis, had the lowest and highest LC50 respectively.Conclusion: Results indicated that Mentha spicata and Eucalyptus camaldulensis, had the lowest and highest LC50 re­spectively. Several other plant extract also showed significant mortality. The formulation of these plants should be pre­pared and evaluate at the field condition against malaria vectors.  

Original Article

  • XML | PDF | downloads: 233 | views: 220 | pages: 353-361
    Background: Every year, thousands of cases and many deaths from scorpion sting are reported in tropical areas of South and Southwestern parts of Iran. The aim of this study was to identify the fauna and dangerous species of scorpi­ons in Rou­dan County, southern Iran.Methods: This descriptive study was conducted in 10 stations in Hormozgan Province. Scorpion sampling was done randomly by searching for their shelter and digging out their nests during day, and with the use of UV light during night from February 2013 to October 2014. Data of scorpion stings were obtained from health center of Hormozgan Province during 2014–2016.Results: Overall, 155 scorpions were collected on a set of eight species belonging to Buthidae and Hemiscorpiidae fam­ilies. These species were identified as Mesobuthus persicus, Mesobuthus phillipsi, Hottentotta schach, Odontobuthus doriae, Compsobuthus persicus, Orthochirus farzanpayi, Androctonus crassicauda and Hemiscorpius acanthocercus. One thousand and twenty-seven cases of scorpion sting were recorded during 2014–2016 with a peak period in summer. Most of cases were <44yr old. Five out of six medically important scorpions in Iran were actively identified in the study area.Conclusion: Results of this study would greatly help to identify risk factors of scorpion sting in high-risk areas for planning, management and treatment of patients with scorpion sting in these areas.
  • XML | PDF | downloads: 157 | views: 160 | pages: 362-377
    Background: Anopheles gambiae (Diptera: Culicidae) transmit malaria parasite that causes malaria fever in humans, causing millions of deaths every year among infants in tropical countries. This study was undertaken to assess the tox­icity of Ocimum basilicum and Ocimum gratissimum against pre-adult stages and adult malaria vector, An. gambiae and non-targeted aquatic organism, fingerlings of Clarias garipienus.Methods: Ethalonic extracts of O. basilicum and O. gratissimum were prepared according to the method described by WHO. The larvae and pupae of An. gambiae were exposed to plant extracts for 24h and their mortality was recorded. Toxicity of Ocimum species on non-targeted organism, fingerlings of C. garipienus was also investigated.Results: Ocimum basilicum showed remarkably potency against pre-adult stages and adults An. gambiae causing 100% mortality at 0.4% concentration within 24h of treatment. The LC50 and LC90 of O. basilicum were lower than O. gratti­simum in all stages of An. gambiae studied. Ocimum basilicum and O. gratissimum extracts significantly reduced the number of bites by the vector given a range of 72.25% to 81.75% protection. Ocimum species at the tested concentra­tions did not significantly reduce the number of fingerlings introduced.Conclusion: Ocimum species at the tested concentrations did not significantly reduce the numbers of non-targeted or­ganisms, fingerlings introduced. Therefore, O. basilicum and O. gratissimum could be used to reduce malaria preva­lence in the endemic areas of Nigeria as it poses no threat to aquatic organisms.
  • XML | PDF | downloads: 179 | views: 181 | pages: 378-390
    Background: Scorpions pose one of the most important public health and medical problems in tropical and subtropi­cal regions of the world, especially in developing countries. This study was conducted to determine the fauna and spatial distribution of scorpions. Methods: In this descriptive study, scorpions were captured using ultra-violet (UV) light, pitfall traps and digging methods in North Khorasan Province, northeastern Iran in 2017. After being encoded, the collected scorpions were stored in plastic containers of 70% ethanol and then transferred to the medical entomology lab of Tehran University of Medical Sciences for species identification based on morphological keys. In addition, Arc GIS 9.3 software was utilized for mapping spatial distribution of scorpions. Results: Overall, 143 scorpions were captured and identified. All of collected scorpions belonged only to Buthidae family. They were also classified into four genera (Androctonus, Mesobuthus, Odontobuthus, Orthochirus) and five species: M. eupeus (59.44%), A. crassicauda (16.78%), O. doriae (12.59), M. (Olivierus) caucasicus (9.09%), and O. farzanpayi (2.10%). Furthermore, spatial distribution of scorpions was performed in this area. Conclusion: Regarding the diversity, high frequency and wide geographical distribution of scorpions and their long-term seasonal activity in this area, the probability of occurrence of scorpion sting is high. Therefore, in order to pre­vent the occurrence of this public health problem, health educational programs be implemented by health- care pro­viders in the area.
  • XML | PDF | downloads: 203 | views: 195 | pages: 378-390
    Background: Culex pipiens play an important role in transmission of infectious diseases. Vector control by chemi­cal pesticides, leads inevitably to resistance development. Understanding the underlying resistance mechanisms can help improve the control programmes and insecticide resistance management.Methods: The total contents of cytochrome p450s and the activities of glutathione S-transferases, alpha- and beta-esterases and inhibition rates of acetylcholine esterase (by propoxur) were measured in the field population of Cx. pipiens collected from Sari County, North of Iran, in 2016 and the results were compared with those of the laborato­ry susceptible strain according to the biochemical assay methods of WHO for adult mosquitoes. Independent sample t-test was used to compare the mean values of enzyme activities/contents between filed and laboratory susceptible popula­tions.Results: The enzyme ratio of cytochrome p450s, alpha- and beta-esterases in the field population was 2.07, 3.72 and 1.36 respectively when compared with the results of the laboratory population. Although not statistically significant, the mean GSTs activities in the field population was marginally less than the laboratory population (ER=0.92). Ace­tylcholinesterase was insensitive to propoxur in 62.82% of the individuals of the tested field population. There was a significant difference (P< 0.05) between all values of the activities/contents of the enzyme in the field population except for GSTs compared with the laboratory susceptible strain. The highest enzyme activity was related to alpha esterase.Conclusion: The present study showed a range of metabolic mechanisms, comprising p450s and esterases combined with target site insensitivity of AChE, contributing to organophosphate, carbamate and pyrethroid resistance in the field population of Cx. pipiens.
  • XML | PDF | downloads: 205 | views: 171 | pages: 378-390
    Background: Mosquito-borne arboviruses such as West Nile (WN), dengue, Rift Valley fever, and Sindbis viruses are reported in Iran, but large-scale studies have not been performed on mosquitoes to find their vectors. A molecular study of the adult mosquitoes (Diptera: Culicidae) for flaviviruses was carried out in a focus of WN infection, Guilan Prov­ince, northern Iran.Methods: Mosquito collections were carried out in five stations of two counties (Anzali and Rasht) using light traps, hand catch by manual aspirators and night landing catch during August–September 2013 and 2014. Molecular screening of WN virus and more widely for Flavivirus RNA was carried out using specific PCR technique.Results: In total, 1015 adult mosquitoes were collected including 8 species representing four genera. The most preva­lent species were Ae. vexans (33.2%), Cx. tritaeniorhynchus (22%), Cx. pipiens (20.7%), and An. maculipennis s.l. (15.6%). Molecular screening was carried out on the 1015 mosquitoes after they were organized as 38 pools according to sex, species and trapping location. None of the pools were positive.Conclusion: Surveillance should be continued while increasing the sampling campaigns due to the presence of wetlands in the region and abundant species which are considered as vectors, feeding both on birds and humans.
  • XML | PDF | downloads: 158 | views: 158 | pages: 399-406
    Background: Phlebotominae sand flies (Diptera: Psychodidae) are the vectors of leishmaniasis. There are different methods for sand fly collection with different performance. The purpose of the current study was to compare the effect of different traps for collection of Phlebotominae sand flies in three endemic leishmaniasis foci in North Khorasan Prov­ince, northeast of Iran.Methods: Sand flies were collected using seven different traps from three villages, three times each twenty days during peak periods of seasonal activity in 2016.Results: A total of 7253 sand flies were collected. The specimens belonged to19 species. Phlebotomus sergenti was the most predominant species in the study area. Light trap baited with Carbon dioxide (CLT) and sticky paper trap (SPT) caught 22.6% and 22.3% of sand flies respectively. Animal baited trap (ABT) and white Shannon trap (WST) caught significantly fewer sand flies than the other traps. The sex ratio was different by phlebotominae sand fly species and collection methods. The sex ratio was highest in SPT and lowest in black Shannon trap (BST). Species diversity and species richness in SPT were more than other traps.Conclusion: Our findings confirm that CLT and SPT are the most efficient sand fly collection methods. CLT is higher attractive for females and Phlebotomus genus and is an ideal method for monitoring the population of Phlebotomus ge­nus during surveillance. SPT is an inexpensive, convenient and easy to be used to detect the presence of sand flies at low densities and provide a more realistic estimation of sand flies biodiversity.
  • XML | PDF | downloads: 190 | views: 251 | pages: 407-415
    Background: Culiseta longiareolata is an important vector for many human diseases such as brucellosis, avian influen­za and West Nile encephalitis. It is likely an intermediate host of avian Plasmodium that can transmit Malta fever. The aim of this study was to determine the  susceptibility level of Cs. longiareolata to different classes  of imagicides  which are recommended by World Health Organization .Methods: Larval stages of the Cs. longiareolata were collected from their natural habitats in Marand County at East Azerbaijan Province, northwestern of Iran in 2017. Adult susceptibility test were carried out with using impregnated papers to insecticides including DDT 4%, Cyfluthrin 0.15%, Deltamethrin 0.05%, Propoxur 0.1% and Fenitrothion 1% by standard test kits.Results: Results showed that Cs. longiareolata adult is more susceptible to pyrethroid and carbamate insecticides. Among tested insecticides, Cyfluthrin was the most toxic against Cs. longiareolata with LT50 value of 11.53 minutes and  Fenitrothion had the least toxic  effect (LT50: 63.39 min).Conclusions: This study provided a guideline for monitoring and evaluation of insecticide susceptibility tests against Cs. longiareolata  mosquitoes for further decision making.

Case Report