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ABSTRACT: Methoprene, an insect growth regulator, was evaluated under field conditions against the main malaria vectors in the Islamic Republic of Iran. The effect of 5, 10 and 20 kg ha<SUP>-1</SUP> concentration of methoprene granule formulation and 100 and 200 mL ha<SUP>-1</SUP> concentration of EC formulation was measured to determine any changes in Anophelini larval abundance and IE ratio in both rice fields and artificial ponds. In artificial ponds, granular methoprene at a dose of 20 kg ha<SUP>-1</SUP> inhibited adult emergence by 77.1% after 1 day and 65.9% after 3 days. The emulsifiable concentrate formulation of methoprene at 200 mL ha<SUP>-1</SUP> inhibited adult emergence by 83.7% after 1 day and 32.2% after 3 days. In rice fields, inhibition of emergence was 44.3% at 20 kg ha<SUP>-1</SUP> granule and 35.8% for emulsifiable concentrate at 200 mL ha<SUP>-1</SUP> after 3 days. The results vary depending on the mosquito species, treatment methods, breeding places and type of formulation.
Pakistan Journal of Biological Sciences. 01/2011;
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Asian Journal of animal and veterinary advances, 3(5):321-327. 01/2008; 3:321-327.
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ABSTRACT: Crimean Congo Hemorrhagic Fever (CCHF) is an arboviral zoonotic disease that is asymptomatic in infected animals, but a serious threat to humans. Numerous genera of ticks serve both as vector and reservoir for CCHF virus. CCHF is an endemic disease in different provinces of Iran. In this study by the use of ELISA method, IgG antibodies against CCHF virus were detected in 15(27.8%) out of 54 sheep examined whereas none of the high risk human samples were positive in Bahar Township, a western region of Iran. Reverse transcription-polymerase chain reaction (RT-PCR) showed CCHFV in 16.4% of hard tick samples. Six of 43(13.9%) Hyalomma ticks were infected. CCHFV was detected in 3 of 23 (13%) Rhipicephalus sp. and I of 5 (20%) of Haemaphysalis sp. Up to now there have been few confirmed human cases in this region. This study confirms the circulation of the virus in this region and so persons in close contact with livestock and also health care workers should be alarmed.
Asian Journal of Animal and Veterinary Advances 01/2008; 3(5):321-327. · 0.87 Impact Factor
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ABSTRACT: The duration of fipronil topical application toxicity of twelve strains of German cockroaches, Blattella germanica (L.), was determined. The Saman strain was collected in 2002, from infested Habitable Convened and the Bustan-7, Bustan-8, Bustan-10, Kouye-Pezeshky, Shahmorady, Zanjan and Kouye-Tehran strains were collected in 2001, from different infested student dormitories and the Fayyazbaghesh, Mogtameh and Kouye-Dokhteran strains were collected in 1997 from two infested hospitals and one student dormitory, respectively in Tehran, Iran. In the topical application bioassay, the average LD<sub>50</sub> of susceptible strain was 1.8, 1.3 and 0.96 ng per insect after 24, 48 and 72 h, respectively and the average LD<sub>95</sub> was 3.4, 2.6 and 2.2 ng per insect after 24, 48 and 72 h, respectively. As with the susceptible reference strain, where LD<sub>50</sub> was halved from 24 to 72 h, the LD<sub>50 </sub>of fipronil decreased with time in the field populations. LD<sub>50 </sub>varied > 3-fold from 1.2 to 3.6 ng per insect at 24 h and almost 2.5-fold from 1.2 to 3.0 ng per insect at 48 h. At the end of the bioassay at 72 h, LD<sub>50</sub> varied from 0.94 to 2.5 ng per insect, which is 1.6- and 2.6-fold higher than the standard susceptible value of fipronil and the steep slopes of dose-response curves indicated that the field population of these German cockroach strains was homogenous in response to fipronil. All German cockroach strains showed a similar susceptibility or lower tolerance (1.5 to 2.6-folds) for fipronil compared with the susceptible laboratory strain and the steep slopes of dose-response curves indicated that the field population of these German cockroach strains was homogenous in response to fipronil. These results indicate that the fipronil was relatively slow-acting in topical application bioassay, with LD<sub>50</sub> values decreasing until 72 h and becoming stable thereafter.
Pakistan Journal of Biological Sciences. 01/2006;
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ABSTRACT: The duration of fipronil WHO glass jar method toxicity against twelve strains of feral German cockroaches, Blattella germanica (L.), was determined. In the WHO glass jar bioassay, the average LT<sub>50</sub> of susceptible strain was 16.4,14.3,12.4 and 11.3 exposure minutes after 24,48,72 and 96 h, respectively and the average LT<sub>95</sub> was 20.3,19.9,19.5 and 19.1 exposure minutes after 24,48,72 and 96 h, respectively. As with the susceptible reference strain, where LT<sub>50</sub> was halved from 24 to 96 h, the LT<sub>50 </sub>of fipronil decreased with time in the feral German cockroach strains. LT<sub>50 </sub>varied > 8-folds from 16.2 to 24.7 exposure min at 24 h, 8.4 folds from 14.4 to 22.8 min at 48 h and almost 8.8 folds from 12.5 to 21.3 exposure minutes at 72 h. At the end of the bioassay at 96 h, LT<sub>50</sub> varied from 11.6 to 19.7 exposure minutes, which is 1.0 and 1.7 folds exposure min higher than the standard susceptible value of fipronil. All German cockroach strains showed a similar susceptibility or very low tolerance (1.5 to 1.7 folds) to fipronil compared with the susceptible laboratory strain and the steep slopes of time exposure-mortality curves indicated that the feral German cockroach strains was homogenous in time exposures to fipronil. These results indicate that the fipronil was relatively slow-acting in WHO glass jar method bioassay, with LT<sub>50</sub> values decreasing until 96 h and becoming stable thereafter.
Pakistan Journal of Biological Sciences. 01/2006;
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ABSTRACT: The efficacy of different synthetic pyrethroid-impregnated fabrics was evaluated against susceptible strain of An. stephensi under laboratory condition using a new method of WHO. LD<sub>50</sub>, LD<sub>90</sub> and diagnostic dose of pyrethroids were calculated for each type of insecticides and fabrics. Results revealed that LD<sub>50</sub> of lambdacyhalothrin, deltamethrin, cyfluthrin and etofenprox were 1.84, 8.97, 0.15 and 40.6 mg m<sup>-2</sup> on polyester; 3.19,11.73,10.94 and 103.01 mg m<sup>-2</sup> on nylon and 9.95, 6.68, 46.75, 9.53 mg m<sup>-2</sup> on cotton. The polyester net need the least concentration of insecticide and it showed the maximum mortality and minimum values of LD<sub>50</sub>, LD<sub>90</sub> and diagnostic dose. So it is the best suitable net for impregnation. The cotton was the best for its persistence of insecticides. In all types of nets lambdacyhalothrin was significantly superior in comparison to deltamethrin, cyfluthrin and etofenprox. Some exception was seen in cotton nets impregnated with etofenprox. LD<sub>50</sub>, LD<sub>90</sub> and diagnostic dose were highly decreased in comparison with other pyrethroids.
Pakistan Journal of Biological Sciences. 01/2006;
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ABSTRACT: The effect of torn bednets treated with three dosages of cyfluthrin 5% EW, deltamethrin 10% SC and permethrin 10% EC were evaluated under laboratory condition in. The objective of the present study was to observe the effect of impregnated torn bednets on the number of bites by An. stephensi. A glass tunnel test was designed to induce hungry female mosquitoes to pass through holes cut in the pyrethroid treated nets. A guinea pig used as bait to attract mosquitoes through circular holes in the netting. With untreated netting, 81-95% of laboratory-reared females passed through the holes overnight, 75-93% blood-fed successfully and 0.36-4% died. When the netting was treated with cyfluthrin at doses of 25, 50 and 100 mg a.i. m<sup>-2</sup>, the entry Index (the proportions that passed through the holes overnight) were 43.37, 41.82 and 23.72%; mortality rates were 66.31, 81.45 and 95.99%; and the feeding rate were 16.13, 9.82 and 1.09%. Experiments with deltamethrin treated nets at dosages of 12.5, 25 and 50 mg a.i. m<sup>-2</sup>, the entry index was 78.10, 61.54 and 27.34%, respectively, mortality rates were 53.26, 58.85 and 82.35%; blood feeding rate was 46.72, 31.15 and 13.49%. When the netting was impregnated with permethrin at dosages of 200 and 500 mg a.i. m<sup>-2</sup>, the entry index was 33.58 and 14.95%; mortality rates were 93.80 and 100% and blood-feeding rate was 5.11 and 0.36%. In conclusion it should be stressed that efficacy of pyrethroid impregnated bednets using “Tunnel Tests†showing acceptable protection rate both in lower and higher dosages as well as cause dead in the blood-fed mosquitoes. In addition, the higher dosages of these three pyrethroids provided good levels of protection against An. stephensi .
Journal of Biological Sciences. 01/2006;
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ABSTRACT: The insecticide resistance status in seven field collected strains of the German cockroach, Blattella germanica (L.) against three pyrethroids: permethrin, cypermethrin and cyfluthrin and cross resistance between these pyrethroids and organochlorine DDT were detected by glass jar test method. For detection of pyrethroid resistance in adult males of field collected strains, the glass jar knockdown test was used and the susceptibility level of each field strain was compared with that of a standard susceptible strain based on Resistance Ratio (RR) calculated by dividing the KT 50 of field strain by the KT 50 of standard susceptible strain. Tests were replicated three to six times in groups of ten cockroaches. For detection of DDT resistance in adult males of the field collected strains, the glass jar mortality test was used to compare the susceptibility level of each field strain with that of susceptible strain based on the mortality rate obtained from exposing them to a single discriminating dose. Tests were replicated three or four times in groups of ten cockroaches. The results of this study indicated that all the field-collected strains of German cockroach were resistant to three pyrethroids: permethrin, cypermethrin and cyfluthrin, i.e., the Resistance Ratios (RRs) of different strains ranged from 5.26 to 23.7 fold for permethrin, 2.9 to 20.7 fold for cypermethrin and 2.4 to 11.42 fold for cyfluthrin, respectively. The order of resistance level to three pyrethroid insecticides was permethrin>cypermethrin>cyfluthrin. Among these seven fields collected strains, five showed high resistance to organochlorine DDT indicating the possible cross resistance between three pyrethroid insecticides used in this study and the organochlorine DDT. Present results demonstrated the differential responses among field collected strains of German cockroach to pyrethroid and DDT insecticides. The information achieved on cross resistance between these three pyrethroid insecticides used in this study and organochlorine DDT could provide the preliminary information for a mechanistic study on possible mechanisms of insecticide resistance in pyrethroid resistant strains.
Journal of Biological Sciences. 01/2006;
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ABSTRACT: The species biological form composition and their spatial distribution was studied in south of Iran using egg morphological characters. All three known biological forms of the species; An. stephensi stephensi (type), intermediate and Mysorensis occur in the country; however their distribution and roles in malaria transmission are varied in each province. In Hormozgan province, all three forms were present. The type and intermediate forms with respectively 90 and 10% frequency occurred in urban-coastal or semi urban/rural-plain areas where An. stephensi is highly dominant and is the sole vector of disease. Mysorensis was found only in rural-mountainous areas where malaria is transmitted by other vectors. This is in agreement with the conventional idea that type form is important only in urban settings. However, in Sistan and Baluchistan which is the most malarious region of the country, in various human settings (urban/rural) and different climates only Mysorensis form was found. In Fars (Kazeron) which was previously a malaria endemic area and An. stephensi was the major vector, only intermediate was found. The biological differences in feeding behaviour and the differing vectorial capacity that have been observed in south of Iran can be explained in terms of the availability or limitation of animals` hosts. The results of this study emphasize on independent studies in each region, precaution in generalization and on reconsidering the conventional view about An. stephensi biological forms in western outreaches of the Indo-Pakistan subcontinent.
Pakistan Journal of Biological Sciences. 01/2006;
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Davari B, Vatandoost H,
Ladonni H,
Shaeghi M,
Oshaghi M.A,
H.R.Basseri,
Enayati A.A,
Rassi Y,
Abai M.R,
A.A. Hanfi Bojd,
Akbarzadeh K
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ABSTRACT: Using of insecticides depend largely on the knowledge of the susceptibility levels of malaria vectors to these chemical. In this study, the susceptibility levels of Anopheles stephensi to DDT 4%, dieldrin 0.4%, fipronil 1%, deltamethrin 0.05%, permethrin 0.75%, lambdacyhalothrin 0.05% and cyfluthrin 0.15% were determined according to WHO methods in three endemic malarious regions; Sistan and Baluchistan, Hormozgan and Fars provinces. The LT<SUB>50 </SUB>values of different insecticides were calculated using the probit regression line for each strain. The results showed that An. stephensi is resistant to DDT, dieldrin and fipronil in all regions; however Bandar Abbas strain showed the highest level of resistance to these three insecticides. All the tested strains were sensitive against four pyrethroid insecticides. The LT<SUB>50</SUB> of Bandar Abbas strain against cyfluthrin and deltamethrin with 5.46 and 3.22 min were the highest and the lowest values respectively. The highest and the lowest mortality rates of the Kazeroon strain of An. stephensi were against lambdacyhalothrin and permethrin with 6.80 and 0.682 min, respectively. In Iranshahr region, the figures for deltamethrin, permethrin, lambdacyhalothrin and cyfluthrin were 3.50, 5.10, 3.95 and 5.38 min, respectively. The results of the study suggested a possible cross-resistance between dieldrin and fipronil. Regarding the sensitivity of An. stephensi to different pyrethroids in the malarious regions of Iran, using pyrethroids is still suggested. Performing complementary tests with cyfluthrin on Bandar Abbas strain and with permethrin on Iranshahr strain seems to be necessary.
Pakistan Journal of Biological Sciences. 01/2006;
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Vatandoost H,
R. Abdoljabari Boonab,
Abai M.R,
Oshaghi M.A,
Rassi Y,
Gholizadeh S,
K. Mashhadi-Esmail A. Kousah,
Haghi M,
Gorghani M,
Aliakbarie-Sharabiani B,
M. Seif Farshid,
Piazak N
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ABSTRACT: An entomological survey was carried out on the bionomics of Anophelines species in Kalibar, East-Azerbaijan during the year 2003-2004. The result showed that five Anophelines species comprising A. sacharov i, A. maculipennis , A. superpictus , A. hyrcanus and A. claviger were present in the study area. Based on the species density rate it was assumed that A. sacharovi could play an important role in malaria transmission and A. maculipennis and A. superpictus could be considered as secondary vectors. A. sacharovi was active from May to September which peaks in July and August in outdoor and indoor, respectively. This species was mainly endophil and anthropophil. Biting activity of A. sacharovi took place in the second half of night. Susceptibility tests using the WHO-recommended discriminative doses of insecticides revealed that this species is resistant to DDT, tolerant to dieldrin and susceptible to malathion, fenitrothion, permethrin, and deltamethrin. A. maculipennis had high density at the beginning of summer, then its population fell down slowly and in early autumn reached to the lowest. The population of this species was found frequently in human shelters and most of its bites took place in the second half of night. Its larvae occurred in slow flowing water and channels with water plants and were more abundant in August.
Pakistan Journal of Biological Sciences. 01/2005;
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ABSTRACT: Naturally, there are different species of Culex mosquitoes in Iran. Culex pipiens complex is widespread in many parts of the country, specially in urban areas. In spite of this fact that Cx. pipiens species is the vector of some orboviruses and filariasis in many countries of the World, it does not have an important role in transmission of diseases in Iran. This species can easily reproduce in urban areas, due to the infection of surface waters and presence of sewage canals. The importance of Cx.pipiens for mankind is in fact, its biting and nuisance, specially at sleeping time. In this study, six types of current military uniforms of Iran’s army were treated by permethrin (0.125 mg. permethrin [AI]/cm2) and examined against the biting of natural population of Cx.pipiens in urban areas in Tehran. Eight volunteer were selected for this study. Six of them put on the treated uniforms and the other two of them wore the untreated uniforms. All the subjects participated in the night biting test for eight active nights July 2004. There was no significant difference in the protection of different treated uniforms against mosquitoes biting. The average number of biting among who wore untreated uniforms (control) was 2.14 mosquito biting/min/person (128.2/hr), While it was 0.23 (13.8/hr) for who wore treated uniforms. The percent protection of treated uniforms, in comparison with untreated ones, was about 89%. The protection percent of treated uniforms for different species of mosquitoes, in comparison with untreated ones, was calculated through determining the species of captured mosquitoes, separately from case and control subjects. The results of species identification among captured mosquitoes of a field study showed that about 95% of them are of Cx.pipiens species, and protection of treated uniforms against them, was estimated 87%. Moreover, as an accompaning environmental consequence a significant reduction in mosquito's density was seen.
International Journal of Environmental Science and Technology. 01/2005;
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ABSTRACT: In this study the susceptibility status of the field and laboratory strains of Anopheles stephensi , the main malaria vector, was determined to different larvicides. Five larvicides, i.e., chlorpyrifos-methyl, Bacillus thuringiensis , temephos, fenitrothion and methoprene were tested using WHO standard test method in the laboratory condition, against the field and lab strains of Anopheles stephensi Liston of Hormozgan province, southeastern Iran. The LC<sub>50</sub> values were calculated from the probit-regression line for each larvicide. Results exhibited the LC<sub>50</sub> values for B. thuringiensis , chlorpyrifos-methyl, fenitrothion, temephos and methoprene as 0.08483, 0.01115, 0.001131, 0.001613, 0.00073 mg L<sup>-1</sup>, respectively for lab strain. The values of 0.521279, 0.016419, 0.002475, 0.003388 and 0.000825 mg L<sup>-1</sup>, were measured as LC<sub>50</sub> against field strain, respectively. From the results it can be concluded that there was significant difference between two strains for B. thuringiensis , temephos and fenitrothion at the LC<sub>50</sub> level. The field strain was more tolerant than lab strain to the three larvicides. At diagnostic dose as recommended by WHO both strains are susceptible to all larvicides, therefore they can be applied for malaria vector control in the region.
Pakistan Journal of Biological Sciences. 01/2005;
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ABSTRACT: Visceral leishmaniasis is one of the most important health problems in Iran which is transmitted by sandflies species to human. In order to determine vector/s of the disease an investigation was carried out in Meshkinshahr district, the most important focus of the disease in Ardebil province, north west of Iran, during 2001-2005. Using sticky papers, CDC light traps and aspirators, totally 2500 sandflies were collected and identified at the species level. Host blood preference and natural infection of female specimens to promastigotes were tested, respectively using ELISA and dissection followed by PCR assay using species-specific kinetoplast minicircle primers. Results showed that six species of Phlebotomus kandelakii, P. perfiliewi transcaucasicus, P. papatasi, P. jacusieli, P. caucasicus and P. sergenti were present in the district, where P. kandelakii with 40% was the most prevalent species. Anthropophilic index of P. kandelakii species was calculated 32.8%, indicating a strong preference to human. Among the dissected female sandflies, only 11 out of 1002 (1.1%) of P. kandelakii was found naturally infected with promastigotes. Species-specific amplification of the Giemsa stained promastigote slides revealed specific PCR products of Leishmania infantum DNA in the infected P. kandelakii sand-flies. Having found high prevalence and anthropophic index and natural infection to Leishmania infantum provide enough evidences to incriminate the species of P. kandelakii as the main and proven vector of visceral leishmaniasis for the first time in the region and in science.
Pakistan Journal of Biological Sciences. 01/2005;
