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 arise in temperature, accelerates the insect’s metabolic rates, increases egg production and makesblood feeding more frequent. It also shortens the time period required for the development ofpathogens within insects. Visceral leishmaniasis (VL) is one of the most important vector-bornediseases transmitted by different sandfly species. In this study, a phenological model was used toestimate the number of generations, peak activity and temporal variability of sandflies in the mainVL foci in northwest Iran.Methods: Development requirements of different life stages of a Phlebotomus papatasi laboratorycolony 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 andsingle triangle model. Sandflies population dynamics was monitored in the field during the seasonalactivity 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 wasenough to support one complete life cycle and growth of the next generation up to late larvalinstar. Larvae of the second generation hibernate through winter and the first adult populationappears in the mid to late June of the next year when they receive at least 182 ADD from thebeginning 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 completelyin late September. This is the first degree day model related to sandflies in the most important VLfoci of Iran.Interpretation & conclusion: Further studies in various regions with variable climate arerecommended in order to better estimate and understand the development time, population dynamicsand activities of the vectors which in turn could be used in proper implementation of effectivevector control programmes

Molecular assay on Crimean Congo Hemorrhagic Fever virus in ticks (Ixodidae) collected from Kermanshah Province, Western Iran

Background: Crimean-Congo Hemorrhagic Fever (CCHF) is a feverous and hemorrhagic disease endemic in some parts of Iran and caused by an arbovirus related to Bunyaviridae family and Nairovirusgenus. The main virus reservoir in the nature is ticks, however small vertebrates and a wide range of domestic and wild animals are regarded as reservoir hosts. This study was conducted to determine the infection rate of CCHF virus in hard ticks of Sarpole- Zahab County, Kermanshah province, west of Iran. Methods: From total number of 851 collected ticks from 8 villages, 131 ticks were selected randomlyand investigated for detection of CCHF virus using RT-PCR. Results: The virus was found in 3.8 of the tested ticks. Hyalommaanatolicum, H.asiaticum and Rhipicephalus sanguineus species were found to have viral infection, with the highest infection rate (11.11) in Rh. sanguineus. Conclusion: These findings provide epidemiological evidence for planning control strategies of the disease in the study area

First report on natural Leishmania infection of Phlebotomus sergenti due Leishmania tropica by high resolution melting curve method in Southeastern 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 iidnetenrtnifayl atrnadn sdcirsitbinegdu sispha cLeeri s(hITmSa1n) ioaf snpueccleieasr irnib soasnodm aflli eDsN sAp eacsi mtheen sg.e Rneetsiuc ltms:a rTkherre we aosu tu soef d1 1to5 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. Tidheias l mfoert hlaordg eis s craapleid g,e sneontsyiptiivneg apnrodj escptesc.ifi

Fauna and Monthly Activity of Sand Flies at Zoonotic Cutaneous Leishmanianisis Focus in Qomrooddistrict of Qom Province in 2009

Background and Objectives: Zoonotic cutaneous leishmaniasis (ZCL) is a parasitological disease transmitted by female sand flies. There are several endemic foci of disease in different parts of Iran. The disease is mostly reported from central part of Qom Province including the villages Ghanavat and Qomrood. It is clear that knowledge on sand flies ecologyhas the main role in planning the control of cutaneous leishmaniasis (ZCL). This study was carried out to determinecutaneous leishmaniasis vectors in Gomrood district of Qom provincein 2009. Methods: The present study was a descriptive, cross-sectional one conducted on sand flies (the leishmaiosis vectors). It was carried out in Qomrood area of central district of Qom province during 2009. Sand flies were collected biweekly from indoors (bed rooms, stables, etc.) and outdoors-rodent burrows of three villages in Gomrood district, using 180 sticky traps (castor oil coated white paper 20 x 32 cm) from the beginning (May) to the end (November) of the active season. For species identification, sand flies were mounted in Puri’s medium and identified after 24 hours using the keys of Theodor and Mesghali (1964).Results: A total of 10252 adult sand flies (4578 from indoors and 5674 from outdoors) were collected and identified during May and November 2009. The following seven species were found in indoors: Phlebotomuspapatasi (86.1%), p. salehi (0/021%), P. sergenti (1/74%), p. caucasicus (1/26%), p. alexandri(0/24%), Sergentomyiasintoni (10/35%) and S. theodori(0/26%). The collected species of oudoors were Phlebotomuspapatasi (54/67%), P. sergenti (0/35%), p. alexandri(0/035%), S. sintoni (44/02%) S. dentata (0/21%) S. clydei (0/19%), S. theodori (0/46%) and S. pawlowski (0/05%). The most common sand flies in indoors and outdoors resting places were P. papatasi and S. sintoni. P. salehi was the lowest collected species in Gomrood district. The active peaks of sand flies were observed in late May and late August.The sex ratio i.e. number of males/100 females of P. papatasi was calculated to be 241.5 and 307.3 in indoors and rodent burrows, respectively. Conclusion: Our entomological survey showed that P. papatasi was the dominant species in indoors and outdoors. It seems this species can be probable vector for ZCL in the study area. Nevertheless, it is necessary that more studies are suggested (specially using molecular methods) in order to determinethe proven vector (s)

Morphological method for sexing anopheline larvae

Background & objectives: Most of autocidal control of malaria vectors relies on the rearing andrelease of large numbers of sterile male into a wild population and it would be crucial to separate themales from females before release. This could result in enormous economic benefits in the massrearing and raise the efficiency of the field operations. The development of genetic sexing ofmosquitoes, enabling the release of males only, but impairing the overall fitness of the releasedinsect has been considered greatly. Here we report on a morphological sexing method for thepreferential diagnosis and separation of males in late III and IV instar larvae for the mosquitoesAnopheles stephensi Liston and An. culicifacies s.l. (Diptera: Culicidae), the principal vectors ofhuman malaria in Asia and Indian subcontinent.Methods: Male mosquitoes are identified by their tube like organ at the 9th abdomen segment whichoriginates from segment parallel to the spiracles. Length and width of this organ is measured as66.66 ± 9.5 and 14.3 ± 1.5 μm respectively. The whole length of the organ is 201.63 ± 23.4 μm. Twofried eggs in the anterior portion of the segment are apparent in males. The length of tube in femaleis shorter than the male (almost half of the length–37.95 ± 4.0 μm), its width is slightly stout andwider than the male (16.72 ± 1.4 μm). Two fried eggs in the anterior portion of the segment areabsent. After separation of live male larvae by those characteristics, they were transferred into thetrays and emerged adults were identified to ascertain correct identification of sex.Results: All the larvae with male organs developed into male adults with hairy antennae and clubshaped palpi, whereas all the female larvae developed into adult females.Interpretation & conclusion: The sex separation at the larval stage will provide a clue for embryonicorigin of sex organs, insecticide selection at the larval stage, sex related genes, male sterility andother measures

Anopheline species composition in borderline of Iran-Azerbaijan

Malaria is still one of the most important health-problems in the world and is endemic in Iran. Since 1994, after collapse of former Soviet Union, a new threat of malaria importation emerged from those countries into the northern Iran. This work was carried out to provide further evidence on the status of anopheline species composition, the malaria parasite species, and natural infectivity of mosquitoes distributed in Pars-Abad district, on the borderline of Azerbaijan in northwestern Iran. Mosquitoes were collected from May to December 2008 in anopheline seasonal activity and were identified at the species level. The genus- and species-specific primers against Plasmodium ssrDNA gene were used for specific amplification on female mosquito head. +. thorax. Members of the Anoheles maculipennis complex were identified by sequence analysis of the ribosomal internal transcribed spacer II (ITS2-rDNA). Morphological character-based identification showed that out of 1455 anopheline female specimens, 1121 (77) were of A. maculipennis s.l. and 334 (23) were of Anoheles hyrcanus. Molecular analysis of the species complex indicated the presence of Anoheles sacharovi 984 (67.6) and A. maculipennis 137 (9.4) in the region. None of themosquito's head-thorax was found to be naturally infected by malaria parasite. Results of this study, particularly high dominance of A. sacharovi, suggest a potential risk of malaria epidemic in the region, and the need for a continuous epidemiological surveillance. © 2011 Elsevier B.V

Phlebotomus perfiliewi transcaucasicus is circulating both Leishmania donovani and L. infantum in northwest Iran

Leishmania infantum is the causative agent of infantile visceral leishmaniasis (IVL) in the Mediterranean Basin and, based on isoenzyme typing of the parasite isolated from dogs; this parasite was considered to predominate in the all foci of IVL in Iran. However, based on PCR detection and sequencing of parasite Cysteine Protease B (CPB), only one out of seven sandfly infections in Phlebotomus perfiliewi transcaucasicus was found to be L. infantum in the current investigation. The six other infections were haplotypes of Leishmania donovani, the causative agent of anthroponotic visceral leishmaniasis (AVL) in West Africa and India. The deduced amino acid of the L. donovani haplotype was found to be novel and the shortest CPB protein reported within the Leishmania spp. Circulation of both L. donovani and L. infantum by P. perfiliewi transcaucasicus, in addition to previous data indicating its ability to circulate L. tropica, suggests that this species, like other vectors of VL, is a permissive vector. Finding L. donovani infecting P. perfiliewi transcaucasicus in the area demands extensive and intensive typing of natural Leishmania infections in epidemiological investigations in Iran and the Mediterranean Basin in general

Comparative performance of imagicides on Anopheles stephensi, main malaria vector in a malarious area, southern Iran

Background & objectives: Jiroft district has subtropical climate and prone to seasonal malaria transmission with annual parasite index (API) 4.2 per 1000 in 2006. Anopheles stephensi Liston is a dominant malaria vector. The monitoring of insecticide susceptibility and irritability was conducted using discriminative dose as described by WHO.Methods: The IV instar larvae were collected from different larval breeding places and transported to the temporary insectary, fed with Bemax® and then 2–3 days-old emerged and sugar-fed adults were used for susceptibility and irritability tests employing WHO methods and kits to organochlorine (OC) and pyrethroid (PY) insecticides.Results: Mortality rates of field strain of An. stephensi were 91.3 ± 0.14 and 90 ± 0.47% to DDT and dieldrin, respectively at one hour exposure time but was susceptible to all pyrethroids tested. The average number of take-offs per min per adult was 2.09 ± 0.13 for DDT, 0.581 ± 0.05 for dieldrin, 1.85 ± 0.08 for permethrin, 1.87 ± 0.21 for lambda-cyhalothrin, 1.53 ± 0.13 for cyfluthrin, and 1.23 ± 0.1 for deltamethrin. Interpretation & conclusion: Currently, deltamethrin is being used for indoor residual spraying against malaria vectors in the endemic areas of Iran. The findings revealed that the main malaria species is susceptible to all pyrethroids including deltamethrin, permethrin, cyfluthrin and lambda-cyhalothrin but was tolerant to DDT and dieldrin. This report and the finding are coincided with results of previous studies carried out during 1957–61 in the same area. Irritability tests to OC and PY insecticides revealed the moderate level of irritability to DDT compared to pyrethroids and dieldrin. Monitoring for possible cross-resistance between OC and PY insecticides should come into consideration for malaria control programme