RESUMO
Scorpions are among the most medically important arthropods in Iran, particularly northwestern areas. To date, five scorpion species, i.e. Mesobuthus eupeus, Mesobuthus caucasicus, Androctonus crassicauda, Hottentotta saulcyi, and scorpio maurus, have been identified. The family Buthidae is responsible for most cases of scorpionism in Iran. The Mesobuthus eupeus species belong to this family and is commonly distributed from Turkey to China, including Iran. Among these species, Mesobuthus eupeus is regarded as the most medically important species and responsible for most cases of envenomation in this area. Morphological differences between some species collected in the study area have been reported. The present study, thus, aimed to identify the subspecies of Mesobuthus eupeus in northwestern Iran. Scorpions were captured in the summer months from 37 localities in three northwestern provinces in Iran: West Azerbaijan, East Azerbaijan, and Ardabil. Scorpion collection was carried out using rock rolling and ultraviolet methods. A total of 376 specimens of Mesobutus eupeus (177males and 199 females) were collected and identified as Mesobuthus eupeus (98.4%) and Mesobuthus eupeus philippovitschi (1.6%). Owing to the findings of our study, M.e.philippovitschi has been added to the scorpion fauna of northwestern parts of Iran for the first time. Unlike M.e. eupeus which is widely distributed from plains to mountainous regions, M.e.philippovitschi has limited distribution and is found mostly along the borders with neighboring countries. This subspecies is the most medically important and most prevalent one in the region. The findings of the present study also provide the basis for future consideration of regional antivenom production for this medically important species.
Assuntos
Antivenenos , Escorpiões , Animais , Feminino , Irã (Geográfico)/epidemiologia , Estações do Ano , Especificidade da EspécieRESUMO
Herein, we provide the ecological niches of gastrointestinal nematode infections in Guilan, Mazandaran, and Golestan provinces. For this purpose, 2688 fecal specimens of sheep and cattle were subjected to the flotation method. For modeling procedure, the results were analyzed by considering 23 bioclimatic and environmental variables as well as 96 points/locations. Maximum entropy (model MaxEnt) was used to visualize the spatial distribution of gastrointestinal nematodes. The relative importance of all variables was also assessed by using jackknife analysis. The highest proportion of sheep infection with strongyle-type egg was observed in Golestan province (57.8%) and the lowest in Guilan province (49.5%), and eggs per gram (EPG) was around 21-29. The parasites with the highest proportion of infection in both domestic animals included strongyle-type eggs. Among the different bioclimatic and environmental variables, the biggest contributor to habitat suitability of the gastrointestinal nematode presence was found to be minimum temperature of the coldest month (Bio6), precipitation of driest quarter (Bio17), precipitation of coldest quarter (Bio19), and altitude. The MaxEnt model was able to provide a suitable guidance for predicting the probability distribution of gastrointestinal nematodes under bioclimatic and environmental variables, and the findings pave way for integrated gastrointestinal nematode surveillance and control strategies in the southern strip of Caspian Sea. In addition, the low intensity of gastrointestinal nematodiasis in ruminants may be associated with the frequent administration of anthelmintic drugs, where actions are needed to investigate drug resistance in the areas concerned and to provide anthelmintic drugs administration in a targeted manner.
Assuntos
Distribuição Animal , Doenças dos Bovinos/epidemiologia , Meio Ambiente , Enteropatias Parasitárias/veterinária , Nematoides/fisiologia , Infecções por Nematoides/veterinária , Doenças dos Ovinos/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Fezes/parasitologia , Incidência , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Irã (Geográfico)/epidemiologia , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Prevalência , Ovinos , Doenças dos Ovinos/parasitologiaRESUMO
BACKGROUND & OBJECTIVES: Zoonotic cutaneous leishmaniasis (ZCL) is among the most endemic zoonotic diseases in Golestan Province of Iran. The aim of this study was to find the high risk areas of this infection by considering the distribution of reservoirs and human infection. METHODS: A cross-sectional study was conducted, in which Rhombomys opimus (Gerbils) were captured from different collection sites across the Golestan Province, Iran. records about the occurrence of Rh. opimus in the Province was obtained from earlier studies and were gathered in a database. Furthermore, records about the disease existence were also obtained from the health system database of Golestan Province. Villages with at least three cases of ZcL were considered endemic foci and used as presence sites for Leishmania major. ArcGIS and MaxEnt model were used to map and predict the best ecological niches for both reservoir and parasite. RESULTS: According to the MaxEnt model, the area under Roc curve for Rh. opimus and L. major was 0.92 and 0.89, respectively. The probability of presence for both species in the northeastern part of Golestan Province was more than the other parts. The Jackknife test indicated that factors like temperature and altitude plays significant role in predicting the environmental suitability for ZcL reservoir and parasite, respectively. INTERPRETATION & CONCLUSION: this modeling approach predicted the areas suitable for reservoir host and circulation of parasite to human. These findings can be used in proper mapping, surveillance and control of the CL.
Assuntos
Reservatórios de Doenças/veterinária , Gerbillinae/parasitologia , Leishmaniose Cutânea/epidemiologia , Doenças dos Roedores/parasitologia , Análise Espacial , Zoonoses/epidemiologia , Animais , Estudos Transversais , Reservatórios de Doenças/parasitologia , Ecossistema , Doenças Endêmicas , Humanos , Irã (Geográfico)/epidemiologia , Leishmania major/isolamento & purificação , Leishmaniose Cutânea/transmissão , Modelos Teóricos , Doenças dos Roedores/epidemiologia , Zoonoses/parasitologiaRESUMO
Visceral leishmaniasis (VL) is an important vector-borne disease in Iran. Till now, Leishmania infantum has been detected from five species of sand flies in the country including Phlebotomus kandelakii, Phlebotomus major s.l., Phlebotomus perfiliewi, Phlebotomus alexandri and Phlebotomus tobbi. Also, Phlebotomus keshishiani was found to be infected with Leishmania parasites. This study aimed at predicting the probable niches and distribution of vectors of visceral leishmaniasis in Iran. Data on spatial distribution studies of sand flies were obtained from Iranian database on sand flies. Sample points were included in data from faunistic studies on sand flies conducted during 1995-2013. MaxEnt software was used to predict the appropriate ecological niches for given species, using climatic and topographical data. Distribution maps were prepared and classified in ArcGIS to find main ecological niches of the vectors and hot spots for VL transmission in Iran. Phlebotomus kandelakii, Ph. major s.l. and Ph. alexandri seem to have played a more important role in VL transmission in Iran, so this study focuses on them. Representations of MaxEnt model for probability of distribution of the studied sand flies showed high contribution of climatological and topographical variables to predict the potential distribution of three vector species. Isothermality was found to be an environmental variable with the highest gain when used in isolation for Ph. kandelakii and Ph. major s.l., while for Ph. alexandri, the most effective variable was precipitation of the coldest quarter. The results of this study present the first prediction on distribution of sand fly vectors of VL in Iran. The predicted distributions were matched with the disease-endemic areas in the country, while it was found that there were some unaffected areas with the potential transmission. More comprehensive studies are recommended on the ecology and vector competence of VL vectors in the country.
Assuntos
Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/transmissão , Modelos Biológicos , Psychodidae/fisiologia , Animais , Ecossistema , Humanos , Irã (Geográfico)/epidemiologia , Psychodidae/parasitologiaRESUMO
Due to low efficacy in the field of a local commercial product of Bacillus thuringiensis M-H-14 (Bioflash(®)), a study was designed to assess its efficacy in laboratory, glass standard aquarium, semi-field and field conditions at both target and higher dosages against immature stages of Anopheles spp. and Culex spp. In laboratory conditions, the LC50 values of wettable powder and granule formulations were 227 and 1031 ppm respectively against a susceptible strain of An. stephensi. Following application of wettable powder and granules at 56.1 mg/aquarium, the survival rates of the exposed larvae to the granule formulation were 65.6% and 54.2% on days 6 and 8 respectively. In the artificial ponds, the larval density was reduced to 38.9%, 39.3% and 65.1% at dosages of 2, 4 and 8 g/m(2) respectively. In rice fields, at a dosage of 2 kg/ha, the density of immature larvae were reduced to 33.1% and 28.6% 7-days post-treatment. Further investigations are needed for the reasons for the low efficacy of this larvicide.
Assuntos
Bacillus thuringiensis , Culicidae/microbiologia , Controle de Mosquitos/métodos , Animais , Anopheles/crescimento & desenvolvimento , Anopheles/microbiologia , Culex/crescimento & desenvolvimento , Culex/microbiologia , Culicidae/crescimento & desenvolvimento , Irã (Geográfico) , Larva/microbiologia , Controle Biológico de VetoresRESUMO
Due to low efficacy in the field of a local commercial product of Bacillus thuringiensis M-H-14 [Bioflash[registered sign], a study was designed to assess its efficacy in laboratory, glass standard aquarium, semi-field and field conditions at both target and higher dosages against immature stages of Anopheles spp.and Culex spp.In laboratory conditions, the LC[50]values of wettable powder and granule formulations were 227 and 1031 ppm respectively against a susceptible strain of An.stephensi.Following application of wettable powder and granules at 56.1 mg/aquarium, the survival rates of the exposed larvae to the granule formulation were 65.6% and 54.2% on days 6 and 8 respectively.In the artificial ponds, the larval density was reduced to 38.9%, 39.3% and 65.1% at dosages of 2, 4 and 8 g/m[2]respectively.In rice fields, at a dosage of 2 kg/ha, the density of immature larvae were reduced to 33.1% and 28.6% 7-days post-treatment.Further investigations are needed for the reasons for the low efficacy of this larvicide
في ضوء تضاؤل الكفاءة للمنتج التجاري المحلي المستحضر من العصية الثورنجية صمم الباحثون دراسة لتقييم كفاءته في المختبر ضمن حوض مائي زجاجي معياري، وفي ظرف ميدانية وشبه ميدانية لكل من الجرعات المستهدفة والجرعات الأعلى ضد المراحل غير الناضجة من أنواع الأنوفيلات وأنواع الباعضات. وفي الظروف المختبرية، كانت قيم الجرعة القاتلة للنصف من مستحضرات المسحوق المرطب جزءا بالمليون ومن الحبيبات جزءا بالمليون، ضد الذراري المستجيبة من الأنوفيلة الأسطفانية. وبعد تطبيق المسحوق المرطب والحبيبات على حوض مائي بمقدار 65.1 مغ/حوض وجد الباحثون أن معدل بقاء اليرقات على قيد الحياة بعد تعرضهن لمستحضر الحبيبات كان 65.6 % في اليوم 6، و 54.2 % في اليوم 8. أما في الأحواض الاصطناعية فإن كثافة اليرقات انخفضت إلى 38.9 % بجرعة 2 غرام/متر مربع، وإلى 39.3 بجرعة 4 ميلي غرام، وإلى 65 % بجرعة 8 غرام/متر مربع. وفي حقول زراعة الأرز فقد أدت جرعة مقدارها 2 كيلو غرام/هيكتار إلى انخفاض كثافة اليرقات غير الناضجة إلى 33.1 % و 28.6 % بعد مرور 7 أيام على المعالجة. وهناك حاجة لمزيد من الدراسات حول أسباب انخفاض كفاءة مبيدات اليرقات
En raison de la faible efficacité sur le terrain d'un produit commercial local de Bacillus thuringiensis M-H-14 [Bioflash[R], une étude a été élaborée pour évaluer son efficacité en laboratoire, en aquarium de verre standard ainsi que dans des conditions déterraient de semi-terrain à des doses cibles mais aussi à des doses supérieures contre des Anopheles spp.et des Culex spp.à des stades immatures.Aux conditions de laboratoire, les valeurs de la CL[50]pour la poudre mouillable et les formulations en granulés étaient de 227 et 1031 ppm respectivement sur une souche sensible d'An.stephensi.Après application de poudre mouillable et de granules à 56, 1 mg/aquarium, les taux de survie des larves exposées à la formulation en granules étaient de 65, 6 % et 54, 2 % aux jours 6 et 8 respectivement.Dans les plans d'eau artificiels, la densité larvaire a été réduite, passant à 38, 9 %, 39, 3 % et 65, 1 % à des doses de 2 g/m[2], 4 g/m[2]et 8 g/m[2]respectivement.Dans les rizières, à une dose de 2 kg/ha, la densité des larves immatures a été réduite, passant à 33, 1 % et 28, 6 %, sept jours après le traitement.Des recherches supplémentaires sont nécessaires pour expliquer la faible efficacité de ce larvicide
Assuntos
Bacillus thuringiensis , Culicidae , Larva , Química Farmacêutica , Anopheles , CulexRESUMO
During 2008-2009 a total of 67 individuals of rodents, Tetera indica, Meriones hurrianae, Meriones libycus and Gerbillus nanus were trapped in three areas, Bampor, Daman and Qasre Qand from Iranshahr and Nikshahr districts. There is a significant difference between comparative abundance of four species (P<0.05). A total of 1422 ectoparasites collected including 299 mites (21%), 127 fleas (8.9%), 972 lice (68.4%) and 24 ticks (1.7%). Significant findings amongst the ectoparasites is the lice group with three species identified, Laelaps accuninata, Andralaelaps hermophrodita and Paracheylaellaps pyriformis being the first record in the study areas. All four captured genera of rodents are known as main/ potential reservoir hosts of zoonotic cutaneous leishmaniasis. The migration habit of rodents may affect the spatial distribution of parasitic ticks and their transmitted diseases like CCHF, which has been reported in recent years from Sistan and Baluchestan province. Monitoring of rodent populations and their ectoparasites will help to predict the potential of zoonotic arthropod-borne diseases.
Assuntos
Ectoparasitoses/veterinária , Doenças dos Roedores/epidemiologia , Animais , Animais Selvagens , Ectoparasitoses/epidemiologia , Ectoparasitoses/parasitologia , Irã (Geográfico)/epidemiologia , Prevalência , Doenças dos Roedores/parasitologia , RoedoresRESUMO
BACKGROUND & OBJECTIVES: Malaria is the most important mosquito-borne disease in Iran. It is endemic in south to southeastern part of the country. Knowledge about bio-ecology of vectors will support authorities for appropriate management of the disease. Bashagard district is one of the main endemic areas for malaria in south of Iran. This study was conducted to determine anopheline fauna, diversity and affinity in the area, characterization of larval habitats, and mapping their potential distribution across the district. METHODS: The potential aquatic habitats for Anopheles larvae were extracted from Indian Remote Sensing Satellite (IRS) image and digital elevation model of the area using GIS. Surface water bodies were sampled monthly during 200910 for anopheline larvae, while characteristics of their physical environment were recorded and water samples were analyzed. RESULTS: A total of 4511 Anopheles larvae were found during the year with the lowest and highest frequencies in February and April, respectively. Dominant species was Anopheles culicifacies. The Shanon diversity index ranged from 0.5700.829 at fixed collection sites, while the affinity index was significant among some vector species. CONCLUSION: Riversides and riverbeds were the main breeding places which provided sandy, rocky, and clay beds for different species. The potential breeding places as well as distribution of collected species were mapped. Knowledge about ecology of malaria vectors provides information to health sector for effective control programs.
Assuntos
Anopheles/classificação , Anopheles/crescimento & desenvolvimento , Biodiversidade , Ecossistema , Animais , Doenças Endêmicas , Feminino , Humanos , Irã (Geográfico)/epidemiologia , Malária/epidemiologia , FilogeografiaRESUMO
Bashagard district is one of the important malaria endemic areas in southern Iran. From this region a total of 16,199 indigenous cases have been reported in recent years. The aim of this study was to determine the situation of the disease and provide the risk map for the area. ArcGIS9.2 was used for mapping spatial distribution of malaria incidence. Hot spots were obtained using evidence-based weighting method for transmission risk. Environmental factors including temperature, relative humidity, altitude, slope and distance to rivers were combined by weighted multi criteria evaluation for mapping malaria hazard area at the district level. Similarly, risk map was developed by overlaying weighted hazard, land use/land cover, population density, malaria incidence, development factors and intervention methods. Our results reveal that the disease mainly occurs in north and east of the study area. Consequently the district is divided into three strata. Appropriate interventions are recommended for each stratum based on national malaria policy. Malaria hazard and risk map, stratification based on relevant information and data analyzing provide a useful method preparedness and early warning system for malaria control, although regular updating is required timely.
Assuntos
Controle de Doenças Transmissíveis/métodos , Doenças Endêmicas , Malária/epidemiologia , Animais , Tomada de Decisões , Geografia , Humanos , Incidência , Irã (Geográfico)/epidemiologia , Medição de RiscoRESUMO
Concerns about traditional chemical pesticides has led to increasing research into novel mosquito control methods. This study compared the effectiveness of 2 different types of polystyrene beads for control of mosquito larvae in south-east Islamic Republic of Iran. Simulated field trials were done in artificial pools and field trials were carried out in 2 villages in an indigenous malaria area using WHO-recommended methods. Application of expanded polystyrene beads or shredded, waste polystyrene chips to pool surfaces produced a significant difference between pre-treatment and post-treatment density of mosquitoes (86% and 78% reduction respectively 2 weeks after treatment). There was no significant difference between the efficacy of the 2 types of material. The use of polystyrene beads as a component of integrated vector management with other supportive measures could assist in the control of mosquito-borne diseases in the Islamic Republic of Iran and neighbouring countries.
Assuntos
Anopheles/fisiologia , Insetos Vetores/fisiologia , Malária/prevenção & controle , Controle de Mosquitos/métodos , Poliestirenos/química , Animais , Anopheles/parasitologia , Insetos Vetores/parasitologia , Irã (Geográfico) , LarvaRESUMO
Bashagard is an important malaria endemic area in south of Iran. An epidemiological and entomological survey was performed during 2002-2010. The aim of study was to determine malaria situation, species composition of anopheline mosquitoes and susceptibility status of main vectors to insecticides/larvicides. A total of 13,490 malaria cases were recorded, Plasmodium vivax (99.64%), P. falciparum (0.35%) and mix cases (0.01%). The highest and lowest Annual Parasite Incidence (API) were observed in 2007 (145.72/1000) and 2009 (6.29/1000), respectively. Anopheles culicifacies, An. dthali, An. stephensi, An. superpictus, An. fluviatilis, An. moghulensis, An. turkhudi and An. apoci were collected from the area. Two peak activities occur in April and October. The first five species were confirmed as malaria vectors in Iran. No indication of sporozoite in mosquitoes using molecular method was performed. Susceptibility tests using diagnostic dose of insecticides and larvicides showed only resistance of An. stephensi to DDT. Tolerance in An. stephensi to deltamethrin and bendiocarb is reported. The same phenomenon was observed in An. culicifacies to DDT, propoxur and deltamethrin, and in An. dthali to malathion and deltamethrin. Larvae of vectors were susceptible to all larvicides, except for An. stephensi that exhibited tolerance to fenthion. In conclusion it should be emphasized that malaria transmission is a complex process in Bashagard. This event is attributed to five proven vectors with different behaviors which are active in the area. Regarding tolerance of vectors to deltamethrin, resistance management is suggested by using new insecticide with novel mode of action.
Assuntos
Anopheles/crescimento & desenvolvimento , Anopheles/parasitologia , Malária Falciparum/epidemiologia , Malária Falciparum/transmissão , Malária Vivax/epidemiologia , Malária Vivax/transmissão , Controle de Mosquitos/métodos , Adolescente , Animais , Anopheles/classificação , Criança , Pré-Escolar , Coinfecção/epidemiologia , Coinfecção/prevenção & controle , Coinfecção/transmissão , Tolerância a Medicamentos , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Resistência a Inseticidas , Inseticidas/farmacologia , Irã (Geográfico)/epidemiologia , Malária Falciparum/prevenção & controle , Malária Vivax/prevenção & controle , Masculino , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Estações do AnoRESUMO
Concerns about traditional chemical pesticides has led to increasing research into novel mosquito control methods. This study compared the effectiveness of 2 different types of polystyrene beads for control of mosquito larvae in south-east Islamic Republic of Iran. Simulated field trials were done in artificial pools and field trials were carried out in 2 villages in an indigenous malaria area using WHO-recommended methods. Application of expanded polystyrene beads or shredded, waste polystyrene chips to pool surfaces produced a significant difference between pre-treatment and post-treatment density of mosquitoes [86% and 78% reduction respectively 2 weeks after treatment]. There was no significant difference between the efficacy of the 2 types of material. The use of polystyrene beads as a component of integrated vector management with other supportive measures could assist in the control of mosquito-borne diseases in the Islamic Republic of Iran and neighbouring countries
Assuntos
Poliestirenos , Anopheles , Culex , Controle de MosquitosRESUMO
Iran is in the malaria pre-elimination stage. In this situation community based strategies are important for malaria control. In order to intensify elimination activities we need to have a better understanding of the knowledge, attitudes and practices (KAP) of malaria prevention in the community. We carried out a KAP study in one malaria endemic district in southern Iran in 2009 using a structured questionnaire. Five villages with indigenous malaria cases during the previous year and a high potential for anopheline mosquito breeding were selected. All the households in each village were visited and the head of the household or other responsible adult was interviewed. Data were analyzed using SPSS 11.5. A total of 494 respondents from the five villages participated. More than 33% of people in the study area were living in sheds with poor facilities. The illiteracy level of the studied population was high (44.2%) and significantly affected the knowledge and practices of the respondents about malaria control (p<0.05). Descriptive analysis showed significant differences between sex, job and history of malaria infection of the respondents and their knowledge and practices about malaria control (p<0.05). Knowledge of the respondents about the route of transmission in malaria was good; 72.1% knew mosquitoes were the vector. Most people knew at least one symptom of the disease. The practices of respondents were 59.5% for bednet use and 9.3% for screening windows. The knowledge, attitudes and practices of respondents in this survey about malaria control were good in some cases, but in general needed to be improved with educational programs.
Assuntos
Doenças Endêmicas/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Malária/epidemiologia , Malária/prevenção & controle , Animais , Estudos Transversais , Culicidae , Feminino , Habitação/estatística & dados numéricos , Humanos , Insetos Vetores , Irã (Geográfico)/epidemiologia , Masculino , Mosquiteiros/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
This study evaluated the repellency effect of 3 topical repellents (permethrin, DEET and neem tree extract) against 3-5 day old females of laboratory and field strains of Anopheles stephensi. Probing/biting rates on the shaved belly of white rabbits were counted. Effective dose (ED) 50 and ED95 values were calculated by probit statistic software. The results revealed ED50 values of 0.007, 0.005 and 0.191 mg/cm2 for permethrin, DEET and neem, respectively, against the field strain. The figures for the laboratory strain were 0.006, 0.007, 0.156 mg/cm2. Major heterogeneity of response was observed using DEET. Although neem was the least effective agent, extracts of locally produced neem oil offer a promising repellent against mosquito biting.
Assuntos
Anopheles , DEET/administração & dosagem , Glicerídeos/administração & dosagem , Mordeduras e Picadas de Insetos/prevenção & controle , Repelentes de Insetos/administração & dosagem , Permetrina/administração & dosagem , Terpenos/administração & dosagem , Administração Cutânea , Animais , Anopheles/fisiologia , Avaliação de Medicamentos , Comportamento Alimentar/efeitos dos fármacos , Feminino , Insetos Vetores/fisiologia , Irã (Geográfico) , Modelos Animais , Controle de Mosquitos/métodos , Fitoterapia/métodos , Coelhos , Análise de RegressãoRESUMO
This study evaluated the repellency effect of 3 topical repellents [permethrin, DEET and neem tree extract] against 3-5 day old females of laboratory and field strains of Anopheles stephensi. Probing/biting rates on the shaved belly of white rabbits were counted. Effective dose [ED] 50 and ED95 values were calculated by probit statistic software. The results revealed ED50 values of 0.007, 0.005 and 0.191 mg/cm2 for permethrin, DEET and neem, respectively, against the field strain. The figures for the laboratory strain were 0.006, 0.007, 0.156 mg/cm2. Major heterogeneity of response was observed using DEET. Although neem was the least effective agent, extracts of locally produced neem oil offer a promising repellent against mosquito biting
Assuntos
Repelentes de Insetos , Permetrina , DEET , Azadirachta , Coelhos , Administração Tópica , Controle de Mosquitos , Laboratórios , AnophelesAssuntos
Anopheles/efeitos dos fármacos , Controle de Insetos/métodos , Insetos Vetores/efeitos dos fármacos , Inseticidas/toxicidade , Malária/prevenção & controle , Animais , Distribuição de Qui-Quadrado , Irã (Geográfico)/epidemiologia , Larva/efeitos dos fármacos , Malária/epidemiologia , Malária/transmissãoRESUMO
Anopheles stephensi Liston is an important malaria vector in Hormozgan province, where it is the most prevalent anopheline mosquito. It shows two annual activity peaks, one in spring and another in the autumn. In mountainous areas the second peak starts earlier than in coastal regions. Adults are endophilic and endophagic, but in the hot season when people sleep outside buildings they frequently bite outdoors. Larvae are found in a wide-range of habitats, both natural and man-made. All three biological forms of the species, occur in the province, i.e. An. stephensi stephensi (type form), An. stephensi mysorensis, and the intermediate form. An. stephensi mysorensis is found only in rural-mountainous areas, whereas the type and intermediate forms occur in urban-coastal regions and the rural plains, with the type form predominant. The presence of the type form in urban areas and mysorensis in rural areas is consistent with the available epidemiological data for malaria in the region and with the finding in India that the type form is an efficient malaria vector inhabiting urban areas whereas mysorensis is rural and has a lower vectorial capacity. Insecticide susceptibility tests on field collected adult mysorensis and adults from laboratory strains of the type and intermediate forms were carried out according to WHO standard methods. These showed that all three forms are susceptible to bendiocarb, propoxur, malathion, fenitrothion, deltamethrin, permethrin, cyfluthrin, and lambdacyhalothrin, but are resistant to DDT and show low level of tolerance to dieldrin. Examination of the larvicidal activity of malathion, fenitrothion, temephos and chlorpyrifos at diagnostic doses showed that these stephensi forms are susceptible to all larvicides except fenitrothion. Irritability tests to pyrethroid insecticides showed high levels of irritability to permethrin and lambdacyhalothrin, but low irritability to cyfluthrin and deltamethrin. The importance of these findings for the epidemiology and control of malaria in the region are discussed.
Assuntos
Anopheles/crescimento & desenvolvimento , Controle de Insetos/métodos , Insetos Vetores/crescimento & desenvolvimento , Malária/prevenção & controle , Animais , Feminino , Humanos , Resistência a Inseticidas , Inseticidas , Irã (Geográfico) , População Rural , Estações do Ano , População UrbanaRESUMO
BACKGROUND AND OBJECTIVES: Kahnooj district in south of Iran is an endemic area for malaria where Anopheles stephensi (Liston) is a main malaria vector and An. dthali (Patton) a secondary vector. According to the national strategy plan on monitoring of insecticides resistance, this study was performed on susceptibility and irritability levels of An. stephensi and An. dthali to different insecticides in the district. METHODS: The susceptibility and irritability levels of field strains of An. stephensi and An. dthali at the adult and larval stages to discriminative dose of different imagicides was determined as recommended by WHO. RESULTS: Using discriminative dose and WHO criteria it was found that An. stephensi is resistant to DDT and dieldrin with 36.1 +/- 2.3 and 62.2 +/- 1.95 mortality rates, respectively; but susceptible to other insecticides. An. dthali was found to susceptible to all tested insecticides. The larvae of An. stephensi, exhibited 100% mortality for temephos and malathion, but 44 +/- 4.32 for discriminative dose of fenitrothion. The results of irritability level for DDT and pyrethroids showed that permethrin had the most irritancy effect on An. stephensi and An. dthali. DDT and deltamethrin showed the least irritancy effect against An. stephensi with 0.42 +/- 0.08 and 0.77 +/- 0.12 take-offs/min/adult, respectively, however, lambdacyhalothrin had the least irritancy effect against An. dthali with 0.096 +/- 0.02 take-offs/min/ adult. The mean number of take-offs/min/adult with permethrin showed significant difference to DDT, lambdacyhalothrin, cyfluthrin and deltamethrin. INTERPRETATION AND CONCLUSION: Pyrethroid insecticides are being used as indoor residual sprays in Iran. Based on our results, the main malaria vectors in the region are still susceptible to pyrethroid insecticides. Therefore, we propose the use of pyrethroids with low irritancy effect in rotation with carbamate insecticides in two interval seasonal peaks of malaria transmission. Biological control including larvivorous fishes, using of local made Bacillus thuringiensis and larvicides such as chlorpyrifos-methyl are the main larval control in the region. Result on larval test exhibited the susceptibility of main vectors to some larvicides, although the 100% mortality was not obtained using fenitrothion and this is postulated the use of this insecticide in agriculture pest control. Monitoring and evaluation of insecticides resistance in malaria vectors in the region could provide an essential clue for judicious use of insecticides.
Assuntos
Anopheles , Insetos Vetores , Resistência a Inseticidas , Inseticidas , Malária/prevenção & controle , Análise de Variância , Animais , Relação Dose-Resposta a Droga , Irã (Geográfico) , Larva , Análise de Regressão , Especificidade da Espécie , Fatores de TempoRESUMO
Hormozgan Province is located in the south of Iran bordering the Persian Gulf. In this area, malaria is still considered a major health problem. In the province, eleven species of Anopheles were identified: An. pulcherrimus, An. sergenti, An. apoci, An. multicolor, An. subpictus, An. turkhudi, An. fluviatilis, An. stephensi, An. d'thali, An. superpictus, and An. culicifacies, among which only the last five species play an important role in malaria transmission. Larval habitats of malaria vectors varied from clean to brackish water, as well as sewage water, under palm trees, marshland, pools, pounds, drainage, irrigation canals, wells, and water containers. Malathion, fenitrothion, chlorpyrifos, and temephos were tested against An. stephensi, An. fluviatilis and An. d' thali larvae at diagnostic doses recommended by WHO. The results showed susceptibility to malathion, chlorpyrifos and temephos, but fenitrothion was not able to yield 100% mortality.