Journal of Arthropod-Borne Diseases
Volume:3 Issue: 1, Jun 2009

The control of leishmaniasis, a tropical neglected disease, has been concern of Iranian health authori­ties due to the increasing number of cases during the last two decades. The objective of this study was to determine del­tamethrine residue on the impregnated bed nets using HPTLC technique in a leishmaniasis control program in Iran. During this experimental study, a total of 130 small pieces of polyester netting were sewn to top, upper, and lower sides of some bed nets and then were impregnated with deltamethrin. The treated bed nets were distributed in Isfahan and Mashhad areas in April 2003. The samples were cut randomly after impregnation intervals. Deltame­thrin was extracted using acetone from samples and the extract was applied for spotting onto plates. The plates were devel­oped with n-hexane: ethyl acetate, 90+10(v/v), as a mobile phase in a Camage chamber. The qualifying of resi­due was observed in UV cabinet with λ=254 nm wavelength. Data were analyzed using SPSS version 11.5. and Stata Ver­sion 8. A three way ANOVA was used to compare the means of deltamethrin residue in each area, group and measur­ing time. The Kruskal-Wallis test was used to compare the means of residue for each of these factors with the con­trol separately. The retardation factor of deltamethrin was calculated 0.50±0.02. The residues of deltamethrin persisted well on impregnated nets at least for 15 weeks after impregnation. No significant difference could be detected in the loss of residue of insecticide in comparison to measuring times and positions of sampling pieces on the bed nets in these ar­eas. Based on the results of the present study the use of HPTLC technique is recommended instead of other chro­matographic methods for analysis of insecticide residue on the impregnated bed nets.

We aimed to develop a PCR-RFLP assay based on available sequences of putative vertebrate hosts to iden­tify blood meals ingested by field female sand fly in the northwest of Iran. In addition, the utility of PCR-RFLP was compared with ELISA as a standard method. This experimental study was performed in the Insect Molecular Biology Laboratory of School of Public Health, Tehran University of Medical Sciences, Iran in 2006-2007. For PCR-RFLP a set of conserved vertebrate prim­ers were used to amplify a part of the host mitochondrial cytochrome b (cyt b) gene followed by digestion of the PCR products by Hae III enzyme. The PCR-RFLP and ELISA assays revealed that 34% and 27% of field-collected sand flies had fed on hu­mans, respectively. Additionally, PCR-RFLP assays could reveal specific host DNA as well as the components of mixed blood meals. Results of PCR-RFLP assay showed that the sand flies had fed on cow (54%), human (10%), dog (4%), human and cow (21%), dog and cow (14%), and human and dog (3%). The results can provide a novel method for rapid diagnosis of blood meal taken by sandflies. The advan­tages and limitations of PCR and ELISA assays are discussed.

We aimed to evaluate different fibres of bednets impregnated with various pyrethroids. The stability of insecticide on the bednet was measured using different methods of washings as well as local made detergents. The entire test was carried out according to the WHO-recommended methods. In addition, the impact of the numbers of washes on the stability of the insecticides was determined. Permethrin 10% (EC), deltamethrin 10% (SC), lambdacyhalothrin 2.5% (CS) and cyfluthrin 5% (EW) were used at the recommended dosages. Three different lo­cal detergents were used. Two kinds of washing methods (shaking, no shaking) were used and in each method four kinds of washings, i.e. no wash, one wash, two washes and three washes was done. The main malaria vectors, Anophe­les stephensi, which is susceptible to all insecticides (BEECH strain), was tested with impregnated bednets in 3 minutes exposure time and the mortality was measured after 24 hours recovery period. Knock-down was measured as well using appropriate statistical methods. Lambdacyhalothrin has saved its insecticidal impact after being washed, whereas, deltamethrin has lost its activ­ity faster than other insecticides. Tow other insecticides had moderate effect. Golnar soap detergent has least ef­fect on the durability of insecticides, but the Shoma had the most. Whit increasing the times of washing, insecticidal ef­fects was decreased, but shaking had no influence on the decreasing of the quality of insecticidal impact. Results will be useful for local people who wish to use pyrethroid-impregnated bednets with their own lo­cal made detergent and bednets.

Mosquito-borne diseases are a major public health threat in Iran. The objective of this study was to de­ter­mine the fauna of culicinae mosquitoes for future mosquito control programs. Three genera and eleven species of the subfamily Culicinae (Diptera: Culicidae) were collected by dipping tech­nique and identified in Chabahar County, Sistan and Baluchistan Province, southeastern Iran, during January, Feb­ru­ary, and March 2007. The collected species included: Aedes vexans (new occurrence record for the province), Culex arbieeni, Cx. bitaeniorhynchus, Cx. deserticola, Cx. hortensis, Cx. perexiguus, Cx. pipiens, Cx. pseudovishnui, Cx. pusillus, Cx. quinquefasciatus, Cx. sinaiticus, Cx. theileri, Cx. tritaeniorhynchus, Culiseta longiareolata, Ochlerotatus cabal­lus, Oc. caspius, and Uranotaenia unguiculata. Our observations indicate that, in South of Iran hot and wet climatic conditions support the persistence of culicinae mosquitoes. As our study, regular monitoring of culicinae mosquitoes in this area could be the most use­ful for mosquito control and mosquito-borne disease prevention.

Many microorganisms in midgut of mosquito challenge with their host and also other pathogens pre­sent in midgut. The aim of this study was presence of non-pathogens microorganisms like fungal flora which may be cru­cial on interaction between vectors and pathogens. Different populations of Anopheles stephensi were reared in insectary and objected to determine fungal flora in their midguts. The midgut paunch of mosquito adults and larvae as well as breading water and larval food sam­ples transferred on Subaru-dextrose agar, in order to detect the environment fungus. Although four fungi, Aspergillus, Rhizopus, Geotrichum and Sacharomyces were found in the food and wa­ter, but only Aspiragilus observed in the midgut of larvae. No fungus was found in the midgut of adults. This is the first report on fungal flora in the midgut of the adults and larvae of An. stephensi and possible stadial transmission of fungi from immature stages to adults. The midgut environment of adults is not compatible for survivorship of fungi but the larval midgut may con­tain few fungi as a host or even pathogen.

Ectoparasites of mammalian hosts play an important role for transmission of diseases from the host res­ervoirs to human. The aim of this study was to determine the species composition and infestation parameters for para­sitic arthropods associated with Rhombomys opimus. Ectoparasites of R. opimus were collected from seven endemic district of ZCL in Iran including Shirvan and Sfaraysen in North Khorasan Province, Kalaleh in Golestan Province, Damghan and Shahrood in Semnan Prov­ince, and Badrood and Habibabad in Isfahan Province. The areas of study were mainly desert and plain. Rodents were captured using Sherman life traps during active seasons from May to November 2008. Captured rodents were trans­ported to laboratory and their ectoparasites were picked up using brushing against the fur of the rodents. Ecto­parasites were stored in 70% ethanol for their preservation and then identified based on morphological characters. Ectoparasites belonged to one flea species of Xenopsylla nuttalli and one mite species of Ornithonussus ba­coti. The flea species with 75.3% was more common than the mite. O. bacoti might play an important role in trans­mission of rat mite dermatitis among R. opimus colony. Results will provide an essential clue for combating zoonotic diseases in the region.

Scorpions are known as the most widespread poisonous creatures that cause casualties and death to human. They are distributed in tropical and subtropical areas. Among the sixteen Iranian Island in the Persian Gulf, Qeshm Island is the biggest and is located in the focus of the important internal and international commercial marinelines. Furthermore, thousands of tourists also visit the Island every year for its natural beauties and the siteseeings. The present research study was carried out during 1998-99 throughout Qeshm Island in order to know the species of scorpions, their abundance, the distribution and control strategy in order to reduce the scorpion stings and to safeguard the visitors as well as the local population. Collections were made randomly during the night. Samples were searched by black light and then collected by forceps. A total of 102 scorpions were captured. The scorpions were identified as Buthotus jayakari numbered 42 specimens (41.17%) and B. leptochelys numbering only 7 specimens (6.86%) belonging to the family Buthidae. Androctonus crassicauda was collected in the most parts of the Island and considered as the dominant species. The sex ratio was 1:1.53 in favor of females. B. lep­tochelys was rare species and by far restricted in its distribution. Considering the high population of A. crassicauda and its wide distribution, it is regarded to be re­sponsible for the majority of scorpion stings in Qeshm Island.

Qeshm (26.75N, 55.82E), Iran, is 1500 km² island in the Strait of Hormuz. Qeshm is a free trade zone, acting as an important channel for international commerce, and has been the site of much recent development. There is potential risk of stinging ant attacks for residents and visitors that may occur in the island. The aims of this study were to find out the fauna, dispersion, and some of the biological features of ant species with special attention to those, which can play role on the public health of the island. In this cross-sectional study, we surveyed ants around the island using non-attractive pitfall traps and active collection to evaluate potential threats to humans and other species during 2006-2007. All collected specimens were identified using the morphological ant keys. Only six ant species were found: Pachycondyla sennaarensis (41%), Polyrhachis lacteipennis (23%), Camponotus fellah (16%), Cataglyphis niger (9%), Tapinoma simrothi (7%), and Messor galla (4%). We were surprised not to find any cosmopolitan tramp ants so often associated with commerce and development. Instead, all six species may be native to the Middle Eastern region. The most common species, P. sennaarensis, has a powerful sting and appears to do well around human habitations. This species may prove to be a serious pest on the island.

Myiasis is the invasion of body tissues of humans or animals by the larvae of the Diptera or two-winged flies. The vari­ous forms of myiasis may be classified from clinical or entomological point. This study describes the existence of Chry­somya bezziana (Diptera: Calliphoridae) cases as a causative agent of myiasis in 18 and 87 year-old men in two differ­ent regions in Fars Province. To our knowledge, this is the first observation of mentioned species in this prov­ince.