Vol 12 No 1 (2018)

Published: 2018-03-18

Review Article

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    Iran has a wide variety of zoogeographical regions and different seasons. Here are some important mosquito-borne diseases. Mosquitoes normally live in waters. Its aquatic insect fauna is highly unexplored. To being resolved this faunal gap, a variety of literature records from previous century in different parts of Iran was reviewed. In some southern and southeastern foci in Iran, Malaria is still a main endemic disease which is unstable with two seasonal spring and autumn peaks even though Iran is lunching Malaria elimination. This review article showed the wide variety of aquatic insects throughout the country. Researchers can discuss water pollutant and its quality by using aquatic insect fauna as well as biological control for vectors. Types of aquatic in­sects and macroinvertebrates sampling can be useful for water quality monitoring as indicators. Looking at aquatic insects’ life in water could be one of the most cost-effective and the easiest method to assess the water contaminations by different pollutants and will provide a guideline for scientific communities and environmental agencies for decision making.

Original Article

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    Background: Cockroaches are the most prevalent domestic pests of a worldwide distribution. They were recognized as possible vectors of pathogenic bacteria, viruses, fungi and parasites in residential dwellings and hospital environ­ments. The present study isolated and identified yeasts and filamentous fungi from digestive tract of American cock­roaches, collected from three different residential regions of Iran.Methods: Seventy cockroaches were sampled using direct collection (hand catch), vacuum cleaner and sticky traps in Ahvaz, Iran in 2009–2010. Their medically important fungal microorganisms were isolated from digestive tract using standard mycological methods. Filamentous fungi were identified by macroscopic and microscopic examina­tion. Yeasts were identified by API ID32C-32100 kit.Results: A high percentage of cockroaches (88.6%) were detected to carry fungi of medical importance. Overall, 23 fungi species/genera were isolated from the American cockroaches' alimentary tract. The fungi isolated from cock­roaches, from the residential regions were species of Aspergillus, Rhizopus, Penicillium, Mucorales, Alternaria, Cladosporium, Mycelia, Chrysosporium, Candida, Rhodotorula, Zygosaccharomyces, and Debaryomyces. Candida spp. (41.4%), Aspergillus spp. (37.1%) and Rhodotorula spp (27.1%) were the most common fungi recovered on cockroaches. Candida albicans and Candida glabrata were the commonest species of the genus Candida. In addi­tion, Aspergillus niger and A. flavus were the most frequent species of the genus Aspergillus.Conclusion: American cockroaches may carry pathogenic fungi in the urban areas of Ahvaz.
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    Background: Culex pipiens is a mosquito species distributed in different parts of Iran. It is known as vector of some diseases as well as a nuisance insect. A successful control campaign needs to study the biology, ecology and suscep­tibility status of the target pest. The aim of this study was to investigate the susceptibility status of Culex pipiens to some insecticides recommended by WHO in north of Iran.Methods: Larvae were collected from different breeding places in Sari County by standard dipping method. They were reared to adult stage in an under standard condition. World Health Organization (WHO) standard test kits and the diagnostic dose of 12 imagicides were used for adults, while two larvicides were used against larvae.Results: The least and highest mortality rates after exposure to insecticides were 4.7% (Propoxur 0.1%) and 76.4% (Etofenprox 0.5%), respectively. Larvae showed high resistance to temephos (19.19%) and malathion (54.63%). Culex pipiens was found to be resistant to all used insecticides/larvicides at diagnostic dose.Conclusion: Intensive use of pesticides against agriculture and urban pests increased the resistance level of this spe­cies to different insecticides, although currently there is no control program against it. Study on the mechanisms of resistant in this species to different insecticides is recommended.
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    Background: We investigated the hemodynamic changes (Inotropic, chronotropic and arrhythmogenic) in intrave­nously envenomed anesthetized rats with Hemiscorpius lepturus venom. The neutralizing potencies of different drugs and commercial antivenom were assessed simultaneously.Methods: Different doses of the crude venom (100, 200 and 400μg/rat) were injected during five minutes via the femoral vein and cardiovascular changes were recorded in rats in Razi Institute Corporation, Karaj, Iran in 2017. The drugs (Atropine, lidocaine, propranolol and prazosin) were injected before the venom for determination of the coun­teracting effects. Different volumes (100, 500 and 1000µl) of the antivenom were pre envenomed to neutralize cardi­ovascular changes.Results: Temporary hypertension and bradycardia with no arrhythmogenic effects were depicted within twenty minutes. There was a difference in arterial pressure between the venom (400μg/rat) and the vehicle at 8 minutes (114.68±5.1mmHg versus 70.2±4.3mmHg). Elevation of the mean arterial pressure was inhibited by propranolol (2 mg/kg) and neutralized by prazosin (1mg/kg) while lidocaine (4mg/kg) and atropine (1mg/kg) had no effects. Pre­medication with Iranian commercial antivenom (1000μl) produced surprisingly temporary hypertension compared to the vehicle (140.84±4.5 versus 84.3±3.2). It had no neutralizing properties on blood pressure variation before the venom injection. Volume-expanded hypertension phenomenon was ruled out in a parallel study.Conclusion: This venom has vasoconstrictive effects in rats probably due to the presence of norepinephrine like ma­terials in its content or liberated from adrenal gland inhibited by prazosin premedication. The neutralizing effects of antivenom on venom-induced hypertension are questionable.
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    Background: Leishmaniasis is a re-emerging serious international public health problem, and both visceral and cu­taneous types of leishmaniasis became important endemic diseases in Iran. In this study, the relationships between environmental factors (vegetation and elevation) and the prevalence of diseases have been investigated.Methods: All international and national online databases were searched by terms such as leishmaniasis, incidence, prevalence and other related words attributed to Iran and published until first quarter of 2015. The developed data­base in Excel, later imported to the ArcMap for spatial analyst and mapping. Afterwards, the software was used for modeling the relationship between the prevalence/incidence and environmental variables (vegetation and elevation) by both linear and nonlinear regression.Results: After mapping the prevalence data from 144 studies, considering non-parametric ANOVA, the tendency of zoonotic visceral leishmaniasis to presence in high elevation and high vegetation was more than Anthroponotic and zoonotic cutaneous leishmaniasis. While linear regression showed weaker results for modeling, however, additive nonparametric regression analysis suggested that 10km buffers for elevation, and 10 as well as 50km buffers for veg­etation could contribute in better fitness in modeling of these variables.Conclusion: The detailed maps for distribution of disease concluded. The nonlinear regression is a reliable predictor of the relationship between environmental factors and disease incidence, although more and wide researchers are needed to confirm it.
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    Background: The fatal form of leishmaniasis is visceral form (VL), found in some of the countries in the world. Visceral leishmaniasis has been reported sporadically from all provinces in Iran, including Lorestan. This study aimed to characterize parasite species in DAT positive and some of the DAT negative human blood samples of Delfan district, Lorestan Province, central Iran.Methods: Blood samples were collected from different geographical areas of Delfan. Serum was used for DAT test and remained part of molecular study. DNA was extracted by using DNG-plus extracted kit (Cinagen, Iran). Poly­merase chain reaction amplification of Leishmania kDNA and PCR-RFLP of ITS1 was done to identify Leishmania species. Some amplicons were sequenced, submitted to GenBank and analyzed by BLASTn.Results: Expected band of kDNA for L. infantum (720bp) was amplified in 16 out of 186 (8.6%) samples which showed previously anti-Leishmania antibody at different titers or were negative serologically. Using BLASTn, 93% similarity with L. infantum has been shown. The rDNA-ITS1 was amplified only in 9 samples (4.7%). RFLP pattern was similar to what expected for L. infantum.Conclusion: A new emerging hypo-endemic focus, caused by L. infantum, is going to be established in Delphan District, Lorestan Province. Further studies on vector and reservoirs are necessary for the region and other parts of Lorestan Province.
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    Background: Leishmaniasis is one of the most important vector-borne diseases in Iran, existing in a variety of forms ranging from cutaneous to visceral forms. Jask County has been recognized as an endemic focus of the disease in the southeastern region of Iran. This study analyzed the situation of cutaneous leishmaniasis (CL) during 2006–2014.Methods: This cross-sectional analytical study was conducted on CL data got from health sector. ArcGIS 10.3 was exploited for the spatial analysis of CL. Potential high-risk areas of the disease regarding its' current geographical distribution were considered.Results: Overall, 874 CL cases had been registered in the district health center, implying an average incidence of 162.5per 100000. More than 90% of the cases emerged from rural areas. The disease is geographically distributed in the southeastern regions of Jask County. Over one-third of the total study area can be classified as high-risk areas, involving 61 villages with a total population of about 18000. Remarkably, altitude and total precipitation were real­ized to play key roles in CL transmission within the study area.Conclusion: Although the national protocol for the control of ZCL recommends the substantial destruction of rodent colonies serving as reservoirs of the disease in infected foci, critical improvement of the knowledge of the residents in these areas is crucial for community-based management of the disease in Jask County.
  • XML | PDF | downloads: 316 | views: 349 | pages: 85-93
    Background: Malaria, a mosquito-transmitted disease, is still a major human health problem all over the world. Lar­viciding is a component of comprehensive control program to overcome the disease. Negative aspects of synthetic insecticides application, such as environmental safety concerns, have favored use of natural insecticides.Methods: Larvicidal activity of essential oil, extracts and fractions of a wild grown and a cultivated type of Bunium persicum fruits against malaria vector Anopheles stephensi was assessed according to the method described by WHO.Results: Bunium persicum showed remarkable potency against An. stephensi larvae. LC50 values for essential oil, total extract, petroleum ether fraction and methanol fraction were 27.4284, 64.9933, 85.9933 and 255.7486ppm for wild type, and 21.3823, 63.2580, 62.7814 and 152.6357ppm for cultivated one.Conclusion: The results of this study suggest B. persicum as a valuable source of natural insecticides against malaria vector Anopheles stephensi.

Short Communication

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    Background: Dirofilaria immitis is an important filarioid transmitted by culicids. The vector role of these arthropods may be influenced by biological events as melanization against D. immitis larvae. This study aimed to detect the occurrence of melanization in Culex quinquefasciatus, Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus experimentally infected with D. immitis.Methods: Five populations (Cx. quinquefasciatus RECIFE (P1), Ae. albopictus RECIFE (P2), Ae. aegypti RECIFE (P3), Ae. aegypti CAMPINAS (P4) and Ae. aegypti ROCKEFELLER (P5)) were artificially fed with infected blood containing D. immitis microfilariae. Ten mosquitoes per day from each population were dissected for 14 days.Results: Melanized larvae of D. immitis were observed in all population except in P3. The period in which melanized larvae were found varied from the third to the 14th day post-infection. Difference in the number of these larvae was observed between P5 and P2–P3 (P< 0.01), and between P5 and P4 (P< 0.05). Third-stage larvae of D. immitis were detected in all population 14 d post-infection, except in P3, which presented high mortality 24 h post-infection. The melanization observed in the populations herein studied did not indicate refractory since third-stage larvae were observed at the end of the experiment. Most likely, this immune response aimed to control the number of larvae, in order to maintain the equilibrium between vector-parasite.Conclusion: The melanization did not seem to be a limiting factor to the development of this filarioid in these local Brazilian Culicidae populations.

Letter to the Editor