Journal of Arthropod-Borne Diseases
Volume:10 Issue: 1, Mar 2016

The present study was undertaken to study the larvicidal activity of different extracts of Nerium ole­ander leaves, and post-treatment temperature- toxicity relationship of these extracts against Culex pipiens. Further, the most potent extract was used to evaluate its biological and genotoxic activities. Crude extracts of N. oleander leaves were prepared using water, chloroform, acetone and diethyl ether as solvents. Extraction was carried out using soxhlet apparatus. Bioassay test was carried out on the larvae, and the LC50 of each extract was determined. Thus, newly hatched first instar larvae were treated, and the mortality count was recorded daily till pupation (accumulated mortality). The LC50 of diethyl ether extract, as the most potent ex­tract, was used for the further biological and genotoxic studies. The results obtained indicated that diethyl ether extract of N. oleander leaves was the most potent extract, with LC50 of 10500 mg/l. The toxicity of the four extracts, using the LC50, at 10 °C was higher than that at 35 °C. The LC50 of diethyl ether extract significantly decreased the larval duration, pupal duration, percentage of pupation, percentage of adult emergence, longevity of females, fecundity, and oviposition activity index, whereas the growth index and the percentage of development per day of larvae and pupae were significantly increased compared to non-treated insects. Moreover, treatment with this extract induced significant dominant lethality in both male and female adults. It appears that diethyl ether extract of N. oleander leaves is potential control agent to Cx. pipiens.

Crimean-Congo Hemorrhagic Fever Virus (CCHFV) belongs to genus Nairovirus and family Bunyaviridae. The main aim of this study was to investigate the extent of recombination in S-segment genome of CCHFV in Iran. Samples were isolated from Iranian patients and those available in GenBank, and analyzed by phyloge­netic and bootscan methods. Through comparison of the phylogenetic trees based on full length sequences and partial fragments in the S-segment genome of CCHFV, genetic switch was evident, due to recombination event. Moreover, evidence of multi­ple recombination events was detected in query isolates when bootscan analysis was used by SimPlot software. Switch of different genomic regions between different strains by recombination could contribute to CCHFV diversification and evolution. The occurrence of recombination in CCHFV has a critical impact on epidemi­ological investigations and vaccine design.

Algeria is among the most affected Mediterranean countries by leishmaniasis due to its large geo­graphic extent and climatic diversity. The current study aimed to determine the ecological status (composition and diversity) of phlebotomine sandfly populations in the region of Oum El Bouaghi (Northeast Algeria). An entomological survey was conducted during the period May–October 2010 in rural communities of Oum El Bouaghi. Catches of sandflies were carried out using sticky traps in both domestic and peri-domestic envi­ronments of 16 sites located beneath two bioclimatic areas, sub-humid and semi-arid. Most of these sites have vis­ceral and/or cutaneous leishmaniasis cases. A total of 1,363 sandflies were captured and identified. They belong to two genera, Phlebotomus and Ser­gen­tomyia, and five species. The species Phlebotomus perniciosus, P. perfiliewi and Sergentomyia minuta were con­stants. Phlebotomus longicuspis was common and P. papatasi was accidental in the study sites. P. perniciosus and P. perfiliewi are the two possible species that contribute in leishmaniasis transmission across the study area due to their high densities (96 and 49 specimens/m²/night, respectively); these two species dominate other species in all study sites. Findings emphasize the key-role played by P. perniciosus, P. perfiliewi and S. minuta in outlining site similarities based on sandfly densities. The study confirms that the more susceptible sites to leishmaniasis, which hold high densities of these sandflies, were located south of the study area under a semi-arid climate.

Sand fly saliva helps parasite establishment and induce immune responses in vertebrate hosts. In the current study, we investigated the modulation of Phlebotomus papatasi salivary gland antigen expression by sea­sonal and biological factors. Sand flies were grouped according to physiological stages such as unfed, fed, semi-gravid, gravid, parous, nulliparous, infected or non-infected with Leishmania major and based on the season in which they were collected. Salivary gland antigens (SGAs) were analyzed using SDS-PAGE and the antibody response against SGAs in Rhombomys opimus was determined by ELISA and Western blot. The highest protein content was found in the salivary glands of unfed sand flies. The saliva content was higher in parous compared to nulliparous, in summer compared to spring, and in Leishmania-infected compared to non-infected flies. The salivary gland lysate (SGL) electrophoretic pattern variations were observed among sand flies with various physiological stages particularly from 4–9 protein bands of 14–70 kDa. The SGL of unfed and gravid flies had extra protein bands compared to fed and semi-gravid sand flies. There was missing protein bands in SGL of parous compared to nulliparous; and in summer compared to spring collected flies. Rhombomys opimus se­rum reacted strongly with an antigenic band of around 28 kDa in the SGL of all sand fly groups. Certain biological and environmental characteristics of wild populations of vector sand flies affect the protein content and antigenicity of saliva. This might have an important implication in the design of vector-based vaccines.

Ixodid ticks (Acari: İxodidae) and fleas (Siphonaptera) are the major vectors of pathogens threatening animals and human healths. The aim of our study was to detect the infestation rates of East Hedgehogs (Erinaceus concolor) with ticks and fleas in Van Province, eastern region of Turkey. We examined fleas and ticks infestation patterns in 21 hedgehogs, collected from three suburbs with the greater of number gardens. In order to estimate flea and tick infestation of hedgehogs, we immobilized the ectoparasites by treatment the body with a insecticide trichlorphon (Neguvon®-Bayer). On the hedgehogs, 60 ixodid ticks and 125 fleas were detected. All of the ixodid ticks were Rhipicephalus turanicus and all of the fleas were Archaeopsylla erinacei. Infestation rate for ticks and fleas was detected 66.66 % and 100 %, respectively. We detected ticks (R. turanicus) and fleas (A. erinacei) in hedgehogs at fairly high rates. Since many ticks and fleas species may harbor on hedgehogs and transmit some tick-borne and flea-borne patogens, this results are the important in terms of veterinary and public health.

Interest in Tatera indica rodent arises mostly because it is believed that this species is survived among four subspecies reported from Iran, two of which exist in Khuzestan Province. In addition, it might has a role as res­ervoir hosts of zoonotic cutaneous leishmaniasis in the transmission of Leishmania major in some of the widespread Asian foci including southwestern Iran. Diagnostic morphological and molecular markers for T. indica were sought by characterizing from indi­vidual specimens, such as some taxonomic features and mitochondrial cytochrome b gene that had previously proven useful for the taxonomy of rodents. Wild rodents were caught using live wooden and wire traps. The specimens were identified morphologically using external criteria and molecularly by sequencing of Cyt b gene and phylogenetic analyses. Forty one T. indica were collected and identified morphologically in Khuzestan Province, Iran. Two morphotypes of T. indica were found and classified but sequencing and phylogenetic analyses of mitochondrial Cyt b gene did not support any subspecies between two morphotypes of T. indica. Because all 21 sequences of both morphotypes of T. indica had no variation with only one common and novel haplotype (GenBank accession No KP001566). This is the first time that T. indica was characterized molecularly in Iran. There is no molecular evi­dence for T. indica morphotypes or subspecies, and so a population genetics approach using several polymorphic genes might be employed using species-specific molecular markers. In addition, more specimens of T. indica species in large geographical locations should be tested.

Mosquitoes lay eggs in a wide range of habitats with different physicochemical parameters. Ecological data, including physicochemical factors of oviposition sites, play an important role in integrated vector management. Those data help the managers to make the best decision in controlling the aquatic stages of vectors especially using source reduction. To study some physicochemical characteristics of larval habitat waters, an investigation was carried out in Qom Province, central Iran, during spring and summer 2008 and 2009. Water samples were collected during larval collection from ten localities. The chemical parameters of water samples were analyzed based on mg/l using standard methods. Water temperature (°C), turbidity (NTU), total dissolved solids (ppm), electrical conductivity (µS/cm), and acidity (pH) were measured using digital testers. Thermotolerant coliforms of water samples were analyzed based on MPN/100ml. Data were assessed by Kruskal-Wallis test and Spearman Correlation analysis. In total, 371 mosquito larvae were collected including 14 species representing four genera. Some physico­chemical parameters of water in Emamzadeh Esmail, Qomrood, Qom City, and Rahjerd showed significant differ­ences among localities (P< 0.05). The physicochemical and microbial parameters did not show any significant dif­ferences among different species (P> 0.05). There was no significant correlation between the abundance of larvae and the different physicochemical and microbial parameters (P> 0.05). The means of EC, TDS, and phosphate of localities and species were remarkably higher than those of the previous studies. Other parameters seem to be in the range of other investigations.

Visceral leishmaniasis (VL) is one of the most important parasitic zoonotic diseases in the world. Do­mestic dogs are the main domestic reservoirs of VL in endemic foci of Iran. Various methods, including vaccination, treatment of dogs, detection and removal of infected dogs have different results around the world. General policy on control of canine visceral leishmaniasis is protection of them from sand fly bites. The aim of this study was evalua­tion of pour-on application of flumethrin on dogs against blood-feeding and mortality of field-caught sand flies. Once every 20 days from May untill September 2013, the treated and control dogs were exposed with field caught sandflies for 2 hours under bed net traps. After the exposure time, both alive and dead sand flies were trans­ferred in netted cups to the laboratory. The mortality rate of them was assessed after 24 hours. The blood-fed or un­fed conditions were determined 2 hours after exposure to the dogs under stereomicroscope. The blood feeding index was varied from 12.0 to 25.0 % and 53.0 to 58.0 % for treated and control dogs respectively (P< 0.0001). The blood feeding inhibition was 75.0–87.0 % and 41.0–46.0 % for the control and treated dogs (P< 0.0001), respectively.The total mortality rate was 94.0–100 % and 19.0–58.0 % respectively for the treated and control groups (P< 0.001).Conclustion: Application of pour-on flumethrin on dogs caused 90–100 % mortality until 2.5 month and inhibited the blood-feeding of sand flies.

Immunochromatographic based rk39 antibody detection test became popular for the diagnosis of vis­ceral leishmaiasis (VL) because of high sensitivity, rapidity, easy to interpret, and cost effectiveness. However, false positive result after complete cure of the patients is the major limitation with this test. The aim of the study to access the usefulness of non-invasive samples i.e. urine and saliva by rk39 test for the diagnosis of visceral leishmaniasis in comparison to serum. Seventy two clinically suspected VL patients were enrolled in the study among which 61 cases were con­firmed as VL and 11 cases were included in the control group. Serum, urine, and saliva samples of all the cases were tested for rk39 dip stick test. Urine and saliva both were equally sensitive as serum for the diagnosis kala-azar. In the control group, rk39 antibody test was negative in 10 cases out 11 (91%) with saliva in comparison to 4 cases with serum (36%), thereby found to be more specific. Saliva sample found to be highly reliable for the diagnosis of VL cases by rk39 test. The test with saliva sample showed less false positive result in comparison to serum sample, thereby can be used an adjunct with serum sample for the diagnosis of kala-azar in endemic areas.

The North Eastern Region in India is endemic for canine heartworm disease but in clinics accurate diagnosis is some times difficult. The aim of the present study was to determine the prevalence of occult infections for heartworm disease in canine in two geographical regions of North Eastern India. A total of 782 numbers of three categories of dogs namely, working dogs of military and paramilitary forces, pet dogs and stray dogs were screened for the presence of heartworm infection from August 2011 to July, 2012 in Guwahati (Assam) and Aizawl (Mizoram). Conventional, immunological and molecular techniques were followed for this epidemiological study. The criteria to determine the occult heartworm cases were based on the dif­ferences between heartworm positive cases in PCR test and antigen ELISA test. The findings revealed an overall 22.69 percent occult case. The working dogs had highest prevalence (60%) followed by pet (29.16%) and stray dogs (17.75%). The highest percentage of occult heartworm infection was present in working dogs maintained under military or paramilitary forces.

Tropical rat mite (Ornithonyssus bacoti) is reported from many parts of the world and is considered important in transmitting rickettsial pathogens. There have been scanty reports on prevalence of this parasite from India. Following a recent report of O. bacoti infestation in a laboratory mice colony from Nilgiris, Tamil Nadu, In­dia, attempts were made to detect the parasite in its natural reservoir, ie the domestic and peridomestic rats (Rattus rattus). The National Centre for Disease Control, Coonoor is involved in screening plague in domestic and peridomestic rats in Nilgiris and erstwhile plague endemic areas of Southern India. The parasite samples were identi­fied based on the morphological characteristics attributable to O. bacoti and as per description of published literature. Seven mite samples identified as O. bacoti based on morphological characteristics were isolated inci­dentally from domestic and peridomestic rodents in and around the hilly districts of Nilgiris, Southern India, during the routine plague surveillance programme. The identification was based on the morphological characteristics at­tributable to O. bacoti observed under a low power microscope. In India, this is probably the first record of isolation of O. bacoti from domestic and peridomestic ro­dents. Prevalence of such parasite in domestic and peridomestic rats necessitates further investigation on monitoring and surveillance of rickettsial diseases in the locality, as these parasites are considered to be potential vector of transmitting rickettsial pathogens.

Bromeliads can be epiphytic, terrestrial or saxicolous and use strategies to allow water to be re­tained in their leaf axils, where various arthropods can be found. These include mosquitoes, whose larvae are the most abundant and commonly found organisms in the leaf axils. The objective of this study was to look for im­mature forms of mosquitoes (the larval and pupal stages) in bromeliads in municipal parks in São Paulo and to discuss the ecological and epidemiological importance of these insects. From October 2010 to July 2013, immature mosquitoes were collected from bromeliads in 65 munici­pal parks in the city of São Paulo, Brazil, using suction samplers. The immature forms were maintained until adult forms emerged, and these were then identified morphologically. Two thousand forty-two immature-stage specimens belonging to the genera Aedes, Culex, Trichoprosopon, Toxorhynchites, Limatus and Wyeomyia were found in bromeliads in 15 of the 65 parks visited. Aedes albopictus was the most abundant species (660 specimens collected), followed by Culex quinquefasciatus (548 specimens) and Cx. (Microculex) imitator (444). The taxa with the most widespread distribution were Ae. aegypti and Toxorhynchites spp, followed by Ae. albopictus and Cx. quinquefasciatus. Bromeliads in urban parks are refuges for populations of native species of Culicidae and breeding sites for exotic species that are generally of epidemiological interest. Hence, administrators and surveillance and mosquito-control agencies must constantly monitor these microenvironments as the presence of these species endangers the health of park users and employees as well as people living near the parks.