Journal of Arthropod-Borne Diseases
Volume:5 Issue: 2, Dec 2011

There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions. These tests were carried out using WHO recommended bioassay method for adult mosquitoes. The extracts from black pepper was more effective as adulticide with lowest LC50 values (2.26% and 8.4%) against Aedes aegypti and Anopheles stephensi after 24 h of exposure while after 48h (1.56% and 5.11%) respec­tively. In terms of LC90 value black pepper was best with (8.66% and 30.1%) against Ae. aegypti and An. stephensi after 24 h of exposure while after 48h (4.59% and 17.3%) respectively. In terms of LT50 black pepper took 15 h to kill 50% tested population of Ae. aegypti while against An. stephensi it took more than 2 days. In terms of percentage mortality black pepper kill 84% of the population of Ae. aegypti and 44.75% of the An. stephensi population. Black pepper showed best results in term of LC50, LC90, LT50 and percentage mortality against Ae. ae­gypti and An. stephensi. Our study suggested that the plant extracts have potential to kill adult mosquitoes, are envi­ronment friendly and can be used for the control of mosquitoes.

Malaria and leishmaniasis are two most significant parasitic diseases which are endemic in Iran. Over the past decades, interest in botanical repellents has increased as a result of safety to human. The comparative effi­cacy of essential oils of two native plants, myrtle (Myrtus communis) and marigold (Calendula officinalis) collected from natural habitats at southern Iran was compared with DEET as synthetic repellent against Anopheles stephensi on human subjects under laboratory condition. Essential oils from two species of native plants were obtained by Clevenger-type water distillation. The protec­tion time of DEET, marigold and myrtle was assessed on human subject using screened cage method against An. stephensi. The effective dose of 50% essential oils of two latter species and DEET were determined by modified ASTM method. ED50 and ED90 values and related statistical parameters were calculated by probit analysis. The protection time of 50% essential oils of marigold and myrtle were respectively 2.15 and 4.36 hours com­pared to 6.23 hours for DEET 25%. The median effective dose (ED50) of 50% essential oils was 0.1105 and 0.6034 mg/cm2 respectively in myrtle and marigold. The figure for DEET was 0.0023 mg/cm2. This study exhibited that the repellency of both botanical repellents was generally lower than DEET as a synthetic repellent. However the 50% essential oil of myrtle showed a moderate repellency effects compared to mari­gold against An. stephensi.

Hyalomma anatolicum is the well-known hard tick, which is one of the most important livestock and hu­man pathogens vector, wide range in host and distributed in all over the Hyalomma geographic fauna as well as in Iran. Taxonomy of the Hyalomma ssp. is debatable whereas their identification is a problematic work. The reasons for this claim is time consuming Delpy’s researches in Iran also Schulze School, Feldman-Muhsam and the Russian tick workers. We would like to understand morphometric variation in the field collected H. anatolicum in Iran also validat­ing some morphologic quantitative and qualitative characters. A total 247 field-collected tick specimens from different geographical regions in west of Iran includes Khuzestan and Lorestan Provinces were studied. The morphologic characters of the ticks were measured by the cali­brated stereomicroscope ‎armed scaled lens. The measurements were analyzed using SPSS ‎for windows, version 16 on an IBM PC, ‎so varied shapes of species in different geographic ‎regions were drawn by the ‎aid of a drawing tube con­nected to a light stereomicroscope.‎ One way ANOVA test revealed significant differences among the quantitative parameters in five zones (P<‎‎ 0.‎‎00‎‎1‎) also each zone to other zone by Post Hoc Tests e.g. LSD. No significant differences in the lateral grooves length/conscutum length ratio parameter were found. Morphometric variation in Hyalomma spp is poorly studied. The variation in range and quantity of the mor­phometric parameters of H.anatolicum ‎underlies that the correct recognition and key construction for Hyalomma spe­cies dependes ‎on a complement morphometric study on the other species.

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. 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 LT50 and LT90 were determined using probit analysis and regression lines. The LT50 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. 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.

Appropriate methodology for storage biological materials, extraction of DNA, and proper DNA preservation is vital for studies involving genetic analysis of insects, bacteria, and reservoir hosts as well as for molecular diagnostics of pathogens carried by vectors and reservoirs. Here we tried to evaluate the utility of a simple filter paper-based for storage of insects, bacteria, rodent, and human DNAs using PCR assays. Total body or haemolymph of individual mosquitoes, sand flies or cockroaches squashed or placed on the paper respectively. Extracted DNA of five different bacteria species as well as blood specimens of human and great gerbil Rhombomys opimus was pipetted directly onto filter paper. The papers were stored in room temperature up to 12 months during 2009 until 2011. At monthly intervals, PCR was conducted using a 1-mm disk from the DNA impregnated filter paper as target DNA. PCR amplification was performed against different target genes of the organisms including the ITS2-rDNA of mosquitoes, mtDNA-COI of the sand flies and cockroaches, 16SrRNA gene of the bacteria, and the mtDNA-CytB of the vertebrates. Successful PCR amplification was observed for all of the specimens regardless of the loci, taxon, or time of storage. The PCR amplification were ranged from 462 to 1500 bp and worked well for the specified target gene/s. Time of storage did not affect the amplification up to one year. The filter paper method is a simple and economical way to store, to preserve, and to distribute DNA samples for PCR analysis.

Plant extracts and oils may act as alternatives to conventional pesticides for malaria vector control. The aim of this study was to evaluate the larvicidal activity of essential oils of three plants of Apiaceae family against Anophe­les stephensi, the main malaria vector in Iran. Essential oils from Heracleum persicum, Foeniculum vulgare and Coriandrum sativum seeds were hydro distil­lated, then their larvicidal activity were evaluated against laboratory-reared larvae of An. stephensi according to stan­dard method of WHO. After susceptibility test, results were analysis using Probit program. Essential oils were separated from H. persicum, F. vulgare and C. sativum plants and their larvicidal activi­ties were tested. Result of this study showed that F. vulgare oil was the most effective against An. stephensi with LC50 and LC90 values of 20.10 and 44.51 ppm, respectively. All three plants essential oil can serve as a natural larvicide against An. stephensi. F. vulgare oil exhib­ited more larvicidal properties.

Mediterranean visceral leishmaniasis (MVL) is an infectious disease that affects both human and ani­mals. Domestic dogs (Canis familiaris) are principal reservoir hosts of MVL caused by Leishmania infantum. Dogs are definitive hosts for Neospora caninum and a risk factor for infecting intermediate hosts. The immunosuppression caused by visceral leishmaniasis (VL) can promote the occurrence of co-infections with other agents such as neosporo­sis. This study aimed to determine the frequency of co-infection of the both protozoan parasites in the en­demic areas of VL from Meshkin-Shahr District, north-west of Iran. Altogether, 171 serum samples were collected from domestic dogs of Meshkin- Shahr District by multistage cluster sampling from October 2008 to August 2009. The collected serum samples were tested for the detection of simultaneous infection of L. infantum and N. caninum using direct agglutination test (DAT) and indirect ELISA, respectively. Of the 171 domestic dogs, 27 (15.8%) and 52 (30.4%) were showed antibodies against L. infantum and N. caninum, respectively. Simultaneous infections of N. caninum and L. infantum was found in 16 (9.4%) of the dogs. In VL-positive and VL-negative dogs, N. caninum infection was found in 59.3% and 25.0%, respectively. A statisti­cally significant difference was found between VL-positive and VL-negative dogs with N. caninum infection (P= 0.001). These findings indicate that Meshkin-Shahr District in northwestern Iran is an active focus of canine visceral leishmaniasis (CVL). Neospora caninum and L. infantum co-infection is prevalent in the area and infection by L. infantum seems to enhance susceptibility to N. caninum infection in domestic dogs.

Zoonotic cutaneous leishmaniasis (ZCL) is an increasing public health problem in some endemic re­gions. Horseradish peroxidase (HRP) conjugated rabbit anti-Rhombomys opimus (R. opimus) Ig is needed for im­munoblotting and ELISA tests used to explore the immune response of the rodents against the sand fly saliva. In this study, the production of HRP conjugated rabbit anti-R. opimus Ig was conducted for the first time. Rhombomys opimus Ig was purified from serum by protein G affinity chromatography column and in­jected into rabbit to produce anti-R. opimus Ig antibody. The titration of antibody against R. opimus Ig in rabbit se­rum was checked using indirect ELISA. Rabbit anti-R. opimus Ig was purified by Sepharose-4B-R. opimus Ig column. Re­activity of this antibody was assessed by indirect ELISA and was conjugated to HRP by periodate method. Approximately 3.5 mg Ig was purified from 1 ml R. opimus serum using protein G affinity chromatography col­umn. The molecular weight of purified R. opimus Ig was estimated about 150 kDa by SDS-PAGE. Nearly 2.3 mg rab­bit anti-R. opimus Ig was purified from 1 ml immunized rabbit serum. The purified antibody was conjugated to HRP and the optimum titer of HRP conjugated rabbit anti-R. opimus Ig was determined as 1:8000 using direct ELISA. HRP conjugated rabbit anti-Gerbil IgG has been produced by a few companies, but to our knowledge HRP conjugated rabbit anti-R. opimus Ig is not commercially available. Production of HRP conjugated rabbit anti-R. opimus Ig is considerably helpful for immunological studies of R. opimus, the main reservoir host of ZCL in Iran as well as some other countries.