Effects of morphine on the biomass and development rate of Chrysomya albiceps (Diptera: Calliphoridae), a forensically important species.

The aim of this study was to determine the effects of morphine on the biomass and development rate of Chrysomya albiceps (Diptera: Calliphoridae). C. albiceps, a well-known forensically important species which is among the first wave of faunal succession on human cadavers, which makes it a valuable source of information for the estimation of postmortem interval (PMI). Antemortem exposure to substances such as drugs and toxins may have an effect on the biomass and/or on the development rate of insects that feed on carcass, which may directly affect PMI estimation. In this study, three rabbits were administered 12.5, 25 or 50 mg/ml of morphine sulfate via ear perfusion over a period of 3 hours, and a fourth rabbit, which did not receive morphine, was used as a control. The rabbits were sacrificed using chloroform 30 minutes after morphine administration. The tissues were analyzed for the presence of morphine using HPLC-UV. Morphine was detected in all tissues of rabbits that received morphine, except in the bile and spleen of the rabbit which received 12.5 mg/ml dose of morphine. The presence of morphine in rabbit tissues retarded larval development rate, but accelerated the puparial development rate. The rate of development of C. albiceps larvae that fed on rabbits which received 25 and 50 mg/ml dosages of morphine was 9 days each. However, the rate of larval development was similar in the 12.5 mg/ml morphine group and the control; 6 days. Results of this study show that an underestimation of the postmortem interval of 72 h based on larval development and an overestimation of 24 to 48 h based on puparial development is possible if the presence of morphine in tissues is not considered. Moreover, the decreased larval development rate caused an increase larval length and weight compared with the control group. In this study, we found a strong correlation between the concentration of morphine administered and concentrations in rabbit tissues. In the estimation of PMI, it is recommended that effects of drugs such as morphine on the development of carcass colonizers be considered.

Geographic distribution and spatial analysis of Leishmania infantum infection in domestic and wild animal reservoir hosts of zoonotic visceral leishmaniasis in Iran: A systematic review.

Visceral leishmaniasis (VL) is an important parasitic disease which is endemic in different parts of Iran; and domestic and wild canines are principal reservoir hosts of the disease. The objective of this study was to review the spatial distribution of canine VL (CVL) caused by Leishmania infantum in domestic and wild canines in different geographical areas of Iran. An extensive literature search was conducted in different international and national databases, including Cochrane, MEDLINE/PubMed, Scopus, Web of Science and Iran Medex to find articles with the words "visceral leishmaniasis in Iran" in their titles and "canine visceral leishmaniasis in Iran" or "feline visceral leishmaniasis in Iran" or "accidental reservoir hosts of visceral leishmaniasis in Iran" in their subtitles, irrespective of the type and duration of study. Screening of the irrelevant articles from total 36,342, yielded 61 eligible articles. More than 93% of the studies were carried out on domestic dogs (Canis familiaris, n = 57) and the remaining were on other carnivores such as wild canines including foxes (Vulpes vulpes, n = 4), jackals (C. aureus, n = 6) and wolves (C. lupus, n = 6); while studies on domestic cats (Felis catus, n = 3) as well as desert rodents (n = 2) were rare. The average rate of L. infantum infections reported among domestic dogs using direct agglutination test (DAT) in Iran was 12.5%. The highest prevalence rate (14%) was reported from the northwest regions of the country where VL is endemic. The review indicates that CVL is endemic in various parts of Iran and domestic dogs are the main and potential reservoir hosts of the disease. Other carnivores, such as domestic cats and some species of desert rodents (Cricetulus migratorius, Mesocricetus auratus and Meriones persicus) seem to be playing a role in the maintenance of transmission cycle of L. infantum in the endemic areas of the disease.

Detection of Leishmania major DNA within wild caught Phlebotomus papatasi and species composition of sand flies in endemic focus of cutaneous leishmaniasis, in western Iran.

Cutaneous leishmaniasis is one of the most important public health problem in many developing countries. The present study was conducted to determine the vector(s), the parasite and the species composition of sand flies in the Dehloran County during May-November 2012. Sand flies were collected by sticky traps and mounted in Puri's medium for species identification. Polymerase chain reaction (PCR) techniques of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphism (RFLP) were used for identification of DNA of Leishmania parasites in infected sand flies. A total of 82443 specimens comprising 15 species of sand flies (5 Phlebotomus and 10 Sergentomyia) were collected and identified. The species of Phlebotomus papatasi was dominant in outdoor and indoor resting places. Among the 280 specimens of female P. papatasi tested by PCR of kDNA, ITS1-rDNA genes of the parasite followed by RFLP, only 5 of them (1.8 %) were positive to Leishmania major parasites. This is the first molecular detection of leishmania infection of P. papatasi to L. major in this region. The results indicated that, P. papatasi was only species found infected by L. major and the principal vector of disease agent to human.

Predicted Distribution of Visceral Leishmaniasis Vectors (Diptera: Psychodidae; Phlebotominae) in Iran: A Niche Model Study.

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.

Laboratory and field evaluation of two formulations of Bacillus thuringiensis M-H-14 against mosquito larvae in the Islamic Republic of Iran, 2012.

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.

First report on natural Leishmania infection of Phlebotomus sergenti due Leishmania tropica by high resolution melting curve method in South-eastern Iran.

OBJECTIVE: To identify the Leishmania species in infected sand flies by Real-time PCR coupled with HRM analysis. METHODS: Real-time PCR coupled with HRM analysis targeting the first internal transcribed spacer (ITS1) of nuclear ribosomal DNA as the genetic marker was used to identify and distinguish Leishmania species in sand flies specimens. RESULTS: Three out of 115 females of Phlebotomus sergenti (P. sergenti) (2.6%) were positive to Leishmania tropica (L. tropica). CONCLUSIONS: This is the first report on P. sergenti as the main and proven vector of anthroponitic cutaneous leishmaniasis in Dehbakri County using Real-time PCR coupled with HRM analysis. This method is rapid, sensitive and specific for diagnosing of parasites in infected Sand flies and ideal for large scale genotyping projects.

Interleukin 4 (IL-4) gene promoter polymorphisms in Rhombomys opimus, the main reservoir of zoonotic cutaneous leishmaniasis.

Great gerbils (Rhombomys opimus) are the most common gerbils in center to northeast of Iran as well as central Asia and serve as reservoirs for the zoonotic agents, including Leishmania major, the principal etiologic agent of zoonotic cutaneous leishmaniasis (ZCL). The outcome of L. major infection in gerbils is not uniform. Among several immune-related factors including cytokine genes, the polymorphism in interleukin 4 (IL-4) promoter gene showed a great impact on outcome and pathological symptoms of L. major infection at least in mouse model. In this study gerbils' IL-4 promoter gene polymorphism is assessed. Specific primers were designed to develop a PCR-based assay to amplify IL-4 promoter gene to possibly define IL-4 promoter gene polymorphism in great gerbil populations with a range of Leishmania infection and symptoms collected from different foci of the central, north and northeast regions of Iran. The results showed that the designed primers amplify 689bp of the promoter gene. Sequence analysis of the promoter gene revealed five polymorphic sites assembly six haplotypes among the gerbil populations. Further studies are needed to assess whether or not the five polymorphisms cause different outcome phenotypes following infection with L. major in great gerbils. The data might be used to characterize the immune responses of R. opimus against L. major infection.

Laboratory and field evaluation of two formulations of Bacillus thuringiensis M-H-14 against mosquito larvae in the Islamic Republic of Iran, 2012

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

Molecular detection of Leishmania infection in sand flies in border line of Iran-Turkmenistan: restricted and permissive vectors.

A molecular study was carried out to incriminate sand fly vectors of cutaneous leishmaniasis (CL) in rural areas of Sarakhs district, Khorassane-Razavi Province, northeastern Iran, in 2011. Sand flies of Sergentomyia with three species and Phlebotomus with six species respectively comprised 73.3% and 26.7% of the specimens. Phlebotomus papatasi was the most common Phlebotomine species in outdoor and indoor resting places. Leishmania infection was found at least in 17 (22%) specimens including Ph. papatasi (n=9 pool samples), Phlebotomus caucasicus (n=6), Phlebotomus alexandri (n=1), and Sergentomyia sintoni (n=1). The parasites were found comprised Leishmania major (n=5), Leishmania turanica (n=10), and Leishmania gerbilli (n=4). Infection of Ph. papatasi with both L. major and L. turanica supporting the new suggestion indicating that it is not restricted only with L. major. Circulation of L. major by Ph. alexandri, and both L. gerbilli and L. turanica by Ph. caucasicus, in addition to previous data indicating the ability of Ph. alexandri to circulate Leishmania infantum and Leishmania donovani, and Ph. caucasicus to circulate L. major, suggests that these two species can be permissive vectors. The results suggest that Ph. papatasi and Ph. alexandri are the primary and secondary vectors of CL where circulating L. major between human and reservoirs, whereas Ph. caucasicus is circulating L. turanica and L. gerbilli between the rodents in the region.

Natural infection of wild caught Phlebotomus tobbi to Leishmania infantum in East Azerbaijan province, northwestern Iran.

BACKGROUND & OBJECTIVES: Zoonotic visceral leishmaniasis is caused by Leishmania infantum, which is transmitted to humans by bites of phlebotomine sandflies and is one of the most important public health problems in Iran. To detect and identify the Leishmania parasites and their corresponding vector(s), an investigation was carried out in Azarshahr County, a new and important focus of the disease in East Azerbaijan province in northwestern Iran during late April to late October 2010. METHODS: Sandflies were sampled using sticky papers (A4 white paper soaked in castor oil) from inside and outside of the houses and animal shelters, close to the vegetation and crevices. The head and three last abdomen segments of the specimens were removed and mounted in Puri's medium for species identification. The rest of body was subjected to molecular methods for detection of leishmanial parasites. RESULTS: Among 400 female sandflies tested by polymerase chain reaction (PCR) of kDNA, ITS1-rDNA, and CPB genes of the parasite followed by restriction fragment length polymorphism (RFLP), only 2 out of 8 Phlebotomus tobbi were positive to L. infantum parasites. CONCLUSION: The results indicated that, P. tobbi was the only species found infected by L.infantum and the principal vector of the disease agent to human.

Baseline insecticide susceptibility data of Phlebotomus papatasi in Iran.

BACKGROUND & OBJECTIVES: Phlebotomine sandflies (Diptera: Psychodidae) play main role in the transmission of different forms of leishmaniasis in the world. Phlebotomus papatasi is the main vector of zoonotic cutaneous leishmaniasis (ZCL) in Iran. There are several control measures for vector control using different classes of insecticides. The aim of this study was to breed the sandflies which were collected from a hyperendemic focus of the disease in central Iran in the laboratory condition and to determine its baseline susceptibility to commonly used insecticides. METHODS: Sandflies were collected from the field and were reared in insectary. Susceptibility tests were carried out on their generation. Baseline susceptibility of sandflies to DDT and pyrethroids was evaluated based on LT50 values. A total of 1305 specimens were tested using different time intervals. The LT50 and LT90 values were measured according to the WHO standard tests. The results were plotted using probit analysis and regression lines. RESULTS: The results against female sandflies revealed the LT50 values of 1312.66, 253.66, 36.04, 9.38 and 6 sec to DDT (4%), permethrin (0.75%), deltamethrin (0.1%), cyfluthrin (0.15%) and lambda-cyhalothrin (0.05%), respectively. The figures for male sandflies were 1200.97, 310.10, 18.63, 6.08 and 0.77 sec respectively to the above insecticides. CONCLUSION: The results of this study could help to provide a clue for implementation of currently used insecticides. Furthermore, a specific guideline is needed for monitoring and evaluation of insecticide susceptibility test against sandflies.

First detection of Leishmania infantum in Phlebotomus kandelakii using molecular methods in north-eastern Islamic Republic of Iran.

Shirvan district in north-eastern Islamic Republic of Iran is a new focus of visceral leishmaniasis. This study aimed to identify the vector(s), the parasite and the species composition of sand flies in the district during July-September 2009 using polymerase chain reaction techniques. In all, 2088 sand flies were collected from 3 villages. Nine sand fly species were identified: Phlebotomus kandelakii (Shchurenkova), P. major (Annandale), P. halepensis (Theodor), P. papatasi (Scopoli), P. sergenti (Parrot), P. longidactus (Parrot), P. caucasicus (Marzinovsky), Sergentomyia sintoni (Pringle) and S. sumbarica (Perfil'ev). P. sergenti and P. kandelakii were the most prevalent Phlebotomus species at 31.3% and 10.0% respectively. Of 59 female P. kandelakii, 2(3.4%) were naturally infected with L. infantum. This is the first finding of natural infection of P. kandelakii by L. infantum in this region suggesting P. kandelakii may be the vector of L. infantum in the area although it is the second most prevalent phlebotomine species.

Comparative study on the effectiveness of coumavec® and zinc phosphide in controlling zoonotic cutaneous leishmaniasis in a hyperendemic focus in central iran.

BACKGROUND: Zoonotic cutaneous leishmaniasis (ZCL) is an increasing health problems in many rural areas of Iran. The aim of this study was to introduce a new alternative rodenticide to control the reservoirs of ZCL, its effect on the vector density and the incidence of the disease in hyperendemic focus of Esfahan County, central Iran. METHODS: The study was carried out from January 2011 to January 2012. In intervention areas, rodent control operation was conducted using zinc phosphide or Coumavec®. Active case findings were done by house-to-house visits once every season during 2011-2012. To evaluate the effect of rodent control operation on the vector density, sand flies were collected twice a month using sticky traps. RESULTS: The reduction rate of rodent holes in intervention areas with Coumavec® and zinc phosphide were 48.46% and 58.15% respectively, whereas in control area results showed 6.66 folds intensification. The Incidence of ZCL significantly reduced in the treated areas. Totally, 3200 adult sand flies were collected and identified in the intervention and control areas. In the treated area with zinc phosphide, the density of Phlebotomus papatasi was higher in outdoors in contrast with the treated area by Coumavec® which the density of the sand fly was higher in indoors. CONCLUSION: Both rodenticides were effective on the incidence of ZCL and the population of the reservoirs as well. Coumavec® seems to be effective on the outdoor density of the vector. This combination of rodenticide-insecticide could be a suitable alternative for zinc phosphide while bait shyness or behavioral resistance is occurred.

First detection of Leishmania infantum in Phlebotomus kandelakii using molecular methods in North-Eastern Islamic Republic of Iran

Shirvan district in north-eastern Islamic Republic of Iran is a new focus of visceral leishmaniasis. This study aimed to identify the vector [s], the parasite and the species composition of sand flies in the district during July-September 2009 using polymerase chain reaction techniques. In all, 2088 sand flies were collected from 3 villages. Nine sand fly species were identified: Phlebotomus kandeiakii [Shchurenkova], P. major [Annandale], P. halepensis [Theodor], P. popatasi [Scopoli], P. sergentl [Parrot], P. longidoctus [Parrot], P. caucasicus [Marzinovsky], Sergentomyia sintoni [Pringle] and S. sumbarica [Perfii'ev]. P. sergentl and P. kandetakii were the most prevalent Phlebotomus species at 31.3% and 10.0% respectively. Of 59 female P. kandelokll, 2 [3.4%] were naturally infected with L infantum. This is the first finding of natural infection of P. kandelakii by L infantum in this region suggesting P. kandelakii may be the vector of L infantum in the area although it is the second most prevalent phlebotomine species

Molecular Detection of Leishmania infantum in Naturally Infected Phlebotomus perfiliewi transcaucasicus in Bilesavar District, Northwestern Iran.

BACKGROUND: Visceral leishmaniasis is caused by Leishmania infantum, transmitted to humans by bites of phlebotomine sand flies and is one of the most important public health problems in Iran. To identify the vector(s), an investigation was carried out in Bilesavar District, one of the important foci of the disease in Ardebil Province in northwestern Iran, during July-September 2008. METHODS: Using sticky papers, 2,110 sand flies were collected from indoors (bedroom, guestroom, toilet and stable) and outdoors (wall cracks, crevices and animal burrows) and identified morphologically. Species-specific amplification of promastigotes revealed specific PCR products of L. infantum DNA. RESULTS: SIX SAND FLY SPECIES WERE FOUND IN THE DISTRICT, INCLUDING: Phlebotomus perfiliewi transcaucasicus, P. papatasi, P. tobbi, P. sergenti, Sergentomyia dentata and S. sintoni. Phlebotomus perfiliewi transcaucasicus was the dominant species of the genus Phlebotomus (62.8%). Of 270 female dissected P. perfiliewi transcuacasicus, 4 (1.5%) were found naturally infected with promastigotes. CONCLUSION: Based on natural infections of P. perfiliewi transcaucasicus with L. infantum and the fact that it was the only species found infected with L. infantum, it seems, this sand fly could be the principal vector of visceral leishmaniasis in the region.

Susceptibility Status of Phlebotomus papatasi and P. sergenti (Diptera: Psychodidae) to DDT and Deltamethrin in a Focus of Cutaneous Leishmaniasis after Earthquake Strike in Bam, Iran.

BACKGROUND: The cutaneous leishmaniasis (CL) has been occurred in Dehbakri County, located 46 km of Bam District, Kerman Province since 2004-2005. Phlebotomus papatasi is an important vector of zoonotic cutaneous leishmanisis (ZCL) as well as sand fly fever and P. sergenti is considered as main vector of anthroponotic cutaneous leishmaniasis (ACL) in Iran. There are several measures for vector control with emphasizing on insecticides. The objective of this study was to determine the baseline susceptibility of leishmaniasis vectors to the DDT and deltamethrin in an endemic focus of CL in southern Iran. METHODS: Baseline susceptibility tests were carried out on field collected strains of P. papatasi and P. sergenti and tested with WHO impregnated papers with DDT 4.0% and deltamethrin 0.05% in the focus of disease in Dehbakri County during summer 2010. The values of LT(50) and LT(90) were determined using probit analysis and regression lines. RESULTS: The LT(50) value of DDT 4.0% and deltamethrin 0.05% against P. papatasi was 20.6 and 13.6 minutes respectively. The same data for P. sergenti were ranged between 21.8 and 17.7 minutes. CONCLUSION: The results of tests will provide a guideline for implementation of vector control using pesticides such as impregnated bed nets, indoor residual spraying and fogging.

Dynamics of Leishmania infection rates in Rhombomys opimus (Rodentia: Gerbillinae) population of an endemic focus of zoonotic cutaneous leishmaniasis in Iran.

Zoonotic cutaneous leishmaniasis (ZCL) due to Leishmania major is a great public health problem in the Old World. Leishmania major is widely distributed in populations of rodents in arid and savannah regions. In this study, seasonal variation of natural infection with Leishmania parasites in Rhombomys opimus (Rodentia: Gerbillinae) population of an endemic focus of ZCL in Iran was monitored. The study was conducted from October 2007 to October 2008 in the central part of the country. Nested polymerase chain reaction (PCR) assay was used for the detection and identification of Leishmania parasites, and the results were confirmed by PCR-restriction fragment length polymorphism (RFLP). The results showed that Leishmania infection rate was 55.8% (29 out of 52 gerbils) using nested PCR. The highest and lowest Leishmania infection rates were observed in fall and summer, respectively. Gerbils that were found to be infected only with L. major were 5.8%, and that with Leishmania turanica were 23.1%. A mixed natural infection was seen in the rodents with L. major and L. turanica (21.2%), with L. major and L. gerbilli (1.9%), and with all the three species (3.9%). Leishmania major infection alone was seen in fall and winter whereas mixed infection of L. major and L. turanica was observed in all seasons except in summer. Leishmania turanica infection was observed throughout the year. It is concluded that L. major, L. gerbilli, and L. turanica circulate in the population of R. opimus in central part of Iran. Leishmania major infection is usually accompanied by L. turanica in naturally infected gerbils with the highest rate in fall. It is recommended that the role of L. turanica in the epidemiology and transmission of ZCL should be reconsidered.

Molecular epizootiology of rodent leishmaniasis in a hyperendemic area of iran.

BACKGROUND: Zoonotic cutaneous leishmaniasis (ZCL) is an expanding disease and public health problem in Iran. In the current study, natural Leishmania infection rate and seasonal fluctuation of the infection in Rhombomys opimus population of a hyperendemic focus of ZCL in Iran was investigated. METHODS: The study was conducted from October 2006 to October 2008 in Esfahan Province, central part of Iran. An extensive sampling of rodents using Sherman traps was done in different seasons. Nested PCR assay was used for detection and identification of Leishmania species and the results were confirmed using PCR-RFLP. RESULTS: Leishmania infection rate was 58.6% (34 of 58) using nested PCR. 44.8% of the gerbils were infected only with L. turanica and 1.7% with L. gerbilli alone. A mixed natural infection with L. major and L. turanica was seen in 12.1% of the rodents. L. major infection alone was not seen in R. opimus population in the study area. The highest and lowest Leishmania infection rates were observed in fall and spring respectively. L. turanica infection was observed throughout the year whereas mixed infections with L. major and L. turanica was not seen in spring. CONCLUSION: It is concluded that in the study area, L. major, L. gerbilli and L. turanica circulate in the population of R. opimus. Leishmania major infection usually accompanied by L. turanica in naturally infected gerbils with the highest rate in fall. It is recommended that the role of L. turanica in the epidemiology and transmission of ZCL be revisited.

Differential Responses of Anopheles stephensi (Diptera: Culicidae) to Skin Emanations of a Man, a Cow, and a Guinea Pig in the Olfactometer.

BACKGROUND: Biting habit of mosquitoes plays an important role in the epidemiology of mosquito-borne diseases. Mosquitoes use a set of elaborate sensory modalities to find their preferred hosts by exploiting cues emanating from a nearby host. It has been suggested that the chemical profile of skin can provide further support for anthropophilic mosquito species to find their suitable hosts. This study aimed at revealing the value of skin emanation for a zoophilic species like Anopheles stephensi as a model. METHODS: Skin emanations of a man, a cow and a Guinea pig were collected by ethanol soaked cottons. Upwind responses of mosquitoes to 100 and 200 µl of filtered skin materials were non-competitively explored in a dual-choice olfactometer. L-lactic acid and other chemical content of the skin samples were identified by an enzymatic kit and GC-MS, respectively. RESULTS: Unexpectedly, only human skin emanation was resulted in the statistically significant activation and attraction responses of An. stephensi in the wind tunnel. L-lactic acid content of this skin sample was 10 and 29 times more than the cow and the Guinea pig, respectively. The possible role of lactic acid and a few other identified compounds have been discussed here. CONCLUSION: Anopheles stephensi showed higher and more specific upwind responses to human skin emanation in the olfactometer. Undoubtedly, the thorough explanation of this unexpected finding needs further investigation. But, if new data verify this result, then, it may be necessary to reconsider the role of skin emanation and thence the human blood index and vectorial capacity of this zoophilic mosquito.

Application of predictive degree day model for field development of sandfly vectors of visceral leishmaniasis in northwest of Iran.

BACKGROUND & OBJECTIVES: Temperature plays a significant role in insect's development where a rise in temperature, accelerates the insect's metabolic rates, increases egg production and makes blood feeding more frequent. It also shortens the time period required for the development of pathogens within insects. Visceral leishmaniasis (VL) is one of the most important vector-borne diseases transmitted by different sandfly species. In this study, a phenological model was used to estimate the number of generations, peak activity and temporal variability of sandflies in the main VL foci in northwest Iran. METHODS: Development requirements of different life stages of a Phlebotomus papatasi laboratory colony were measured and were subjected to the formula for calculation of accumulated degree day (ADD) for field sandflies using the online soft (UC IPM), using horizontal cut-off method and single triangle model. Sandflies population dynamics was monitored in the field during the seasonal activity in the region and its association with the ADD was tested using SAS software. RESULTS: Populations of sandflies accommodated well with the amount of accumulated degree days (ADD) in the region. During the seasonal activity, a total of 639 ADD were produced which was enough to support one complete life cycle and growth of the next generation up to late larval instar. Larvae of the second generation hibernate through winter and the first adult population appears in the mid to late June of the next year when they receive at least 182 ADD from the beginning of the spring. The highest population density of sandflies was observed in early August, followed by a rapid decrease in early September, with the adult population disappearing completely in late September. This is the first degree day model related to sandflies in the most important VL foci of Iran. INTERPRETATION & CONCLUSION: Further studies in various regions with variable climate are recommended in order to better estimate and understand the development time, population dynamics and activities of the vectors which in turn could be used in proper implementation of effective vector control programmes.