Journal of Arthropod-Borne Diseases
Volume:5 Issue: 1, Jun 2011

There is a little data on Coxiella burnetii (Q fever agent) in Iran. Ticks may play a significant role in the transmission of C. burnetii among animals. The aim of this study was to use polymerase chain reaction for the detec­tion of C. burnetii in ticks collected in Southeast Iran. One hundred and sixty ticks were collected from domestic animals in three localities of Kerman Province, South­east Iran from November to June 2009. The collected ticks were divided into 35 pools and examined by Trans-PCR for C. burnetii. Three pools, each consisting of five female of Hyalomma anatolicum anatolicum and one pool (6 ticks) of Rhipicephalus sanguineus ticks collected from goats and sheep were found to be positive by Trans-PCR. This paper documents the first molecular detection of C. burnetii in ticks, which shows their role as puta­tive vectors and reservoirs for this pathogenic agent.

The mainstay of diagnosis of relapsing fever (RF) is demonstration of the spirochetes in Giemsa-stained thick blood smears, but during non fever periods the bacteria are very scanty and rarely detected in blood smears by mi­cros­copy. This study is aimed to evaluate the sensitivity of different methods developed for detection of low-grade spi­ro­chetemia. Animal blood samples with low degrees of spirochetemia were tested with two PCRs and a nested PCR tar­get­ing flaB, GlpQ, and rrs genes. Also, a centrifuged-based enrichment method and Giemsa staining were per­formed on blood samples with various degrees of spirochetemia. The flaB-PCR and nested rrs-PCR turned positive with various degrees of spirochetemia including the blood samples that turned negative with dark-field microscopy. The GlpQ-PCR was positive as far as at least one spi­ro­chete was seen in 5-10 microscopic fields. The sensitivity of GlpQ-PCR increased when DNA from Buffy Coat Layer (BCL) was used as template. The centrifuged-based enrichment method turned positive with as low concentra­tion as 50 bacteria/ml blood, while Giemsa thick staining detected bacteria with concentrations ≥ 25000 bacteria/ml. Centrifuged-based enrichment method appeared as much as 500-fold more sensitive than thick smears, which makes it even superior to some PCR assays. Due to simplicity and minimal laboratory requirements, this method can be considered a valuable tool for diagnosis of RF in rural health centers.

Trypsin Modulating Oostatic Factor (TMOF) terminates trypsin biosynthesis in adult and larval mos­quito gut. It will inhibit the growth and development of mosquito larvae feeding on it resulting in death by starvation. The objective of this study is to determine the effective dose of Pichia-TMOF and the combination of Pichia-TMOF with Bacillus thuringiensis (Bt) as larvicide on Ae. aegypti larvae. Aedes aegypti first-instar larvae were exposed to various doses of Pichia-TMOF, Bt and combination of Pichia-TMOF and Bt. The development of the larvae were observed and recorded daily during the bioassay larval test until the adult emergence. The results showed that 400 ppm Pichia-TMOF and 300 ppm Pichia-TMOF were able to cause 100% and 67% cumulative mortality on Ae. aegypti larvae on 8th day respectively. At 200 ppm, 100 ppm and 50 ppm con­centra­tion Pichia-TMOF showed obvious stunted effect on Ae. aegypti larvae. Moreover, the combination of 400 ppm Pichia-TMOF with 0.1 ppm Bt showed synergistic effect on Ae. aegypti. Pichia-TMOF inhibited trypsin biosynthesis is potential to act in larval gut causing stunted growth and lar­val development and causing mortality. The combination of Pichia-TMOF and Bt increased the effectiveness in caus­ing larval mortality.

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. 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. 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. 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.

Metarhizium anisopliae strain IRAN 437C is one of the most virulent fungal isolates against house fly, Musca domestica. The objective of this study was to determine the interaction of this isolate with sublethal doses of spino­sad against housefly. In adult bioassay, conidia of entomopathogenic fungus were applied as inoculated bait at 105 and 107 spore per gram and spinosad at 0.5, 1 and 1.5 µg (A.I.) per gram bait. In larval bioassay, conidia were applied as combina­tion of spore with larval bedding at 106 and 108 spore per gram and spinosad at sublethals of 0.002, 0.004 and 0.006 µg (AI) per gram medium. Adult mortality was 48% and 72% for fungus alone but ranged from 66–87% and 89–95% in combination treat­ments of 105 and 107 spore/g with sublethal doses of spinosad respectively. The interaction between 105 spore/g with sublethals exhibited synergistic effect, but in combination of 107 spore in spite of higher mortality, the interac­tion was additive. There was significant difference in LT50 among various treatments. LT50 values in all combination treat­ments were smaller than LT50 values in alone ones. Larval mortality was 36% and 69% for fungus alone but ranged from 58%–78% and 81%–100% in combination treatments of 106 and 108 spore/g medium with sublethals of spino­sad respectively. The interaction was synergistic in all combination treatments of larvae. The interaction between M. anispliae and spinosad indicated a synergetic effect that increased the house fly mortality as well as reduced the lethal time.

Ecological data are important in the vector control management of mosquitoes. There is scattered pub­lished information about the larval habitat characteristics and ecology of the genus Anopheles (Diptera: Culicidae) in Iran and most of available data is in relation to malaria vectors in southern Iran. This cross sectional investigation was carried out to study the mosquito fauna and ecology in Guilan Province, northern Iran, during April–December 2000. Larvae were collected using the standard dipping technique. Larval habitat characteristics were recorded according to water situation (clear or turbid), vegetation, substrate type, sunlight situation, habitat situation (transient or permanent, running or stagnant), habitat type (natural or artificial), and water temperature. In total, 1547 third- and fourth-instar larvae of Anopheles from 90 habitats were collected and morphologi­cally identified. Five species; Anopheles claviger, An.’hyrcanus’, An. maculipennis s.l., An. plumbeus, and An. su­perpictus were identified and respectively comprised 6.3%, 22.4%, 54.4%, 13.0%, and 3.9% of the samples. The mean and range temperatures of the larval habitat water were 19.6oC (n=14) (16–25oC), 22.6oC (n=53) (12–33oC), 23.8oC (n=52) (10–33oC), 11.5oC (n=12) (9–21oC), and 20.4oC (n=7) (12–26oC), respectively. There was a signifi­cant difference in the mean water temperatures (11.5–23.5oC) of the larval habitats of different species (P=0.000). Most of the genus larvae were collected from natural habitats (86.9%) such as river bed pools (46.4%) and rain pools (33.1%) with transient (98.3%), stagnant (99.5%) and clear (95.3%) water, with vegetation (69.9%), mud (42.0%) or gravel (39.7%) substrate in full sunlight (69.6%) or shaded (22.7%) area. A checklist of the province mosquitoes including 30 species and seven genera has been provided. The main larval habitats of the most abundant species, An.’hyrcanus’ and An. maculipennis s.l., in Guilan Province are: river bed pools, rain pools, and rice fields.

The aim of his study was to determine development time and thermal requirements of three myiasis flies including Chrysomya albiceps, Lucilia sericata, and Sarcophaga sp. Rate of development (ROD) and accumu­lated degree day (ADD) of three important forensic flies in Iran, Chrysomya albiceps, Lucilia sericata, and Sarcophaga sp. by rearing individuals under a single constant temperature (28° C) was calcu­lated using specific formula for four developmental events including egg hatching, larval stages, pupation, and eclosion. Rates of development decreased step by step as the flies grew from egg to larvae and then to adult stage; however, this rate was bigger for blowflies (C. albiceps and L. sericata) in comparison with the flesh fly Sarcophaga sp. Egg hatching, larval stages, and pupation took about one fourth and half of the time of the total pre-adult development time for all of the three species. In general, the flesh fly Sarcophaga sp. required more heat for development than the blowflies. The thermal constants (K) were 130–195, 148–222, and 221–323 degree-days (DD) for egg hatching to adult stages of C. albiceps, L. sericata, and Sarcophaga sp., respectively. This is the first report on thermal requirement of three forensic flies in Iran. The data of this study provide preliminary information for forensic entomologist to establish PMI in the area of study.

Due to importance and fatal affect of Red-back spiders, Latrodectus hasselti, a faunistic survey for presence of this spider in Bandar Abbas has been conducted. This animal is considerably the most medically importance spiders all over the world. Live adult spider specimens were collected from Bandar Abbas town using hand catch conventional method and transferred to the laboratory throughout the summer of 2008. They were identified based on mor­phological characteristics and taxonomic keys and confirmed by some external experts. Results showed the occurrence of the red-back spider, L. hasselti from Bandar Abbas, southern port of Iran. Two female specimens were found. The spider had specific morphological characters including black color with an obvious orange to red longitudinal strip on its upper parts of abdomen. Although the specimens were collected from south of the country, however since the region is an important harbor and port and goods come form different parts of world we assume the possibility of arrival from its origin and native breeding sites of the world. Therefore further investigation is needed to clarify the presence of this species in different parts of Iran.