Journal of Arthropod-Borne Diseases
Volume:13 Issue: 1, Mar 2019

Rickettsia felis is an emergent Rickettsial agent whose main vector is Ctenocephalides felis, but ticks, mites and lice are also infected. We aimed to search for molecular evidence of Rickettsia spp. in fleas collected from dogs and wild rodents (Heteromys anomalous) from three villages of Córdoba and Antioquia provinces (Northern of Colombia), where outbreaks of rickettsioses have occurred, and discuss the possible role of fleas on endem ic/enzootic regions for rickettsia. During 2010 and 2012, 649 Ctenocephalides felis felis and 24 Pulex irritans fleas were removed from dogs and wild rodents (Heteromys anomalous), respectively, in 3 locations from Córdoba and Antioquia provinces (Colombia). These fleas were tested into pools for Rickettsial infection by PCR, targeting gltA, ompB, and ompA Rickettsial genes. Almost 20% (30/153) of C. felis felis pools contained Rickettsial DNA. The fragments of ompB gene showed high identity values between sequences from Necocli and Los Cordobas with R. felis strain from Senegal (100% and 99.7% respectively) and all were highly related by phylogenetic analyses. Rickettsial DNA in pools of P. irritans was not detected. Our findings highlighted the endemicity of the infection by R. felis in fleas from northern of Colombia and showed the likely importance of dogs as hosts of C. felis felis fleas and their potential role as reservoirs of R. felis.

Crimean-Congo hemorrhagic fever (CCHF) causes serious health problems in humans. Though ticks of the genera Hyalomma play a significant role in the CCHF transmission it was also found in 31 other thick species. Totally, 1412 ticks from 8 remote sites in Armenia during 2016 were sampled, pooled (3-5 ticks per pool) and tested for the presence of CCHFV antigen using ELISA test. From 359 tick pools, 132 were CCHF virus antigen-positive. From 6 tick species, four species (Rhipicepha lus sanguineus, R. annulatus, R. bursa, Hyalomma marginatum) were positive for the virus antigen and R. sanguineus was the most prevalent (37.9%). Dermacentor marginatus and Ixodes ricinus revealed no positive pools, but both revealed delectable but very low virus antigen titers. The highest infection rate (50%) was observed in R. sanguineus, whereas H. marginatus rate of infection was 1 out 17. For the first time in the last four decades CCHF virus antigen was detected in Ixodid ticks of Armenia. This finding substantiates the role of R. sanguineus in the disease epidemiology; however, the role of H. marginatum in the CCHF virus circulation in the country could not be excluded.

The detection of insecticide resistance in natural populations of Anopheles vectors is absolutely necessary for malaria control. CDC bottle bioassay as a new tools has been employed for detecting the insecticide resistance. For a limit number of mosquito vectors, diagnostic doses and diagnostic times for some insecticides have already been deter mined using this new assay. For the first time in the area, susceptibility levels of Anopheles stephensi was done with DDT, deltamethrin, and bendiocarb using CDC bottle bioassay and compared results with WHO standard test method. Anopheles stephensi were collected in larvae stage from the cisterns of drinking water in Chabahar port which considered as old malaria foci, Sistan and Baluchistan province. The field collected larvae were colonized at the insectary of School of Public Health (SPH), Tehran University of Medical Science. The susceptibility tests were carried out on sugar fed female mosquitoes aged 2–3 days, against DDT 4%, bendiocarb 1% and deltamethrin 0.05% using WHO and CDC susceptibility methods. The mortality and knockdown rates, as well as the parameters of regression analysis, includ ing LT50 and LT90, was calculated separately for the WHO and CDC methods.  The 24h mortality rates of An. stephensi were 28.6% and 25.6% for DDT, 60.8% and 64.6% for bendiocarb and 100% for deltamethrin using both WHO and CDC assay at 30 and 60min respectively. The 50% lethal times (LT50) were estimated 44.9 and 66.2min, 38.9 and 81.8min and 0.7 and 15.0min respectively using both WHO and CDC susceptibility tests. The similar results of susceptibility levels were shown for DDT, bendiocarb and deltamethrin. The lethal times (LT50) showed significant difference using both WHO and CDC bioassay methods.

West Nile fever, as an expanding zoonotic disease, has been reported from different creatures involved in the disease from Iran. In addition to biological mosquito-associated factors, various elements such as their activi ties, distribution, behavior and vectorial capacity could be affected by environmental factors. We determined the dis tribution of West Nile virus (WNV) vectors, the environmental factors affecting WNV transmission and the high-risk areas across West Azerbaijan Province (Northwestern Iran), regarding the potential of WNV transmission using Ge ographical Information System (GIS). Mosquitoes’ larvae and adults were collected from different habitats of the province in 2015 and identified using standard morphological keys. The data regarding the distribution of mosquitoes across the studied area were organized in ArcMap databases. Inverse Distance Weighted (IDW) interpolation analysis was conducted on the data of synoptic stations to find climatic variables in the collection sites of different mosquito species. Layers of transmis sion-related environmental factors were categorized and weighed based on their effects on disease transmission. Overall, 2813 samples of different mosquito species from different regions of the province were collected and identified. According to the GIS analysis, areas in the northeastern province, which have lower altitudes and slopes with higher temperatures and more water bodies, were found to have better condition for the activity of mos quitoes (as high-risk areas: hot spots). The precision of our results was proven to be in line with previous study results that identified high-risk areas, where WNV-infected vectors were captured from these same areas.

The efficacy of biolarvicides may be influenced by species of mosquito, larval age and density, tem perature, water quality, bacterial formulation, and others. The aim of this study was to evaluate the influence of tem perature and chlorine on larvicidal activity of Bacillus thuringiensis Cuban isolates against Aedes aegypti. The influence of temperature (25, 30, 35 °C) and chlorine (2.25mg/L) on the larvicidal activity of eleven B. thuringiensis Cuban isolates (collected between 2007 and 2009) were tested under laboratory conditions following WHO protocols. Bioassay data were analyzed by Probit program. The effect of chlorine and temperature (25, 30, 35 and 40 °C) on the Cry and Cyt proteins of these isolates was determined by SDS-PAGE polyacrylamide gel electro phoresis. The pathogenicity of the isolates U81, X48 was affected at 35 °C. However, A21, A51, L910, and R89 isolates increase their entomopathogen activity at 35 °C. No differences were observed in toxicity of M29, R84, R85 and R87 isolates at different temperatures. The Cry 4, Cry 10 and Cry 11 proteins were reduced in A21, X48, R85 isolates at 35 and 40 °C. The Cyt proteins were reduced at 35 and 40 °C in A21, X48, R85, and A51 isolates. In L910 and R84 isolates, the Cyt toxin was degraded only at 40 °C. In chlorinated water, the lethal concentrations 50 and 90 in A21, A51, M29, R84, U81, and X48 isolates were increase. A21, A51, L910, R85, and X48 isolates have a strong larvicidal activity for the treatment of Ae. aegypti breeding’s sites exposed to high temperature and chlorine.

Timely entomological and insecticide resistance monitoring is a key to generating relevant data for vector management. We investigated the insecticide susceptibility status of Anopheles gambiae s.l. in eight rural farming communities in Southern Gombe, Nigeria. Overall, 3–5 days-old adult female Anopheles mosquitoes reared from field-collected immature stages between September and November, 2014 were exposed to the diagnostic doses of pyrethroids, organophosphate and carbamate insecticides using the Center for Disease Control Bottle bioassay. The observatory knockdown time from exposure to each insecticide was recorded up to two hours. The dead mosquitoes were then identified morphological ly and by molecular assays. Mortality results showed resistance in An. gambiae s.l. populations to bendiocarb (2.3–100%), deltamethrin (39–70%), pirimiphos-methyl (65-95%), dichloro-diphenyl-trichloroethane (0–38.1%), permethrin (0–46.3%) and lambda-cyhalothrin (42.5–86.4%). The few cases of full susceptibility were observed from lamdacyhalothrin exposed population of An. gambiae s.l. in Banbam and Pantami respectively. An. gambiae 177 (45%) was significantly higher (P< 0.05) than An. arabiensis 64 (16.3%), An. coluzzii 34 (8.7%) and An. gambiae/An. coluzzii hybrid 78 (19.8%). A strong evidence of widespread resistance in the major malaria vector species in Southern Gombe to all common classes of insecticides is a justification for the State Malaria Elimination Programme to consciously con sider incorporating insecticide resistance management strategies into control programs in order to sustain the future of current control interventions.

The abundance, diversity, distribution and ecology of mosquitoes (Diptera: Culicidae), especially ar bovirus vectors are important indices for arthropod-borne diseases control. Larvae and adult mosquitoes were collected using the standard methods from different habitats in nine localities of three counties in the East Azerbaijan Province, Northwestern Iran during June to October 2017. In addi tion, species richness (R), Simpson’s diversity index (D), Shannon–Wiener index (H̕) and evenness (E) as measures of diversity, were calculated. Overall, 1401 mosquito specimens including 1015 adults and 386 larvae were collected in the study area. The properties of geographical larval habitats were recorded. Four genera along with 10 species were collected and identified, including Anopheles hyrcanus, An. maculipennis s.l., An. superpictus s.l., Aedes caspius, Ae. vexans, Cu lex pipiens, Cx. theileri, Cx. perexiguus, Culiseta longiareolata and Cs. subochrea. Among the three counties, Ahar region presented the highest species richness (R: 1.5) and diversity values (D: 0.79, H’: 1.74, E: 0.73). This study provides important information on the diversity, distribution and ecology of ten mosquito species in the region. This information leads to a better understanding of mosquito population dynamics in relation to vector control measures.

Theileria is a protozoal parasite that belongs to the phylum Apicomplexa. Theileriosis is an important tick-borne disease caused by various species of Theileria. Among these species, T. lestoquardi (T. hirci) is highly pathogenic, while other species such as T. ovis make Subclinical and mild infections in small ruminant. Therefore, the precise identification of the species and the vector ticks are very essential for epidemiological studies and the design of control programs. This research was conducted with the aim of molecular study to identify Theileria species and vectors in Zabol, eastern Iran in 2015. The presence of Theileria in 80 blood samples and vector ticks was evaluated using PCR method. Of 80 blood samples, PCR analysis showed that 50 samples (62.5%) were infected with Theileria. The eval uation of the first phase PCR with Nested PCR showed that infections with Theileria ovis and Theileria lestoquardi were 67.45% and 32.55% cases respectively. Overall, 110 ticks (78 males and 32 females) were collected and generally two genera and six spe cies including Rhipicephalus bursa (9.1%), Rh. sanguineus (29.1%), Rh. turanicus (10.9%) Hyalomma asiati cum asiati cum (23.63%), Hy. excavatum (10.9%), Hy. anatolicum (16.37%) were detected. After evaluating ticks infection by PCR method, three species of Rh. turanicus, Rh. sanguineus and Hy. asiaticum asiaticum, were infected. Theileria ovis has a high prevalence among the sheep of zabol and Hy. asiaticum asiaticum, Rh. sanguineus and Rh. turanicus may be the main vectors of Theileria species in this area.

The purpose of this study was molecular detection and phylogenetic analysis of Wolbachia species of Dirofilaria immitis. Adult filarial nematodes were collected from the cardiovascular and pulmonary arterial systems of natural ly infected dogs, which caught in different geographical areas of Meshkin Shahr in Ardabil Province, Iran, during 2017. Dirofilaria immitis genomic DNA were extracted.  Phylogenetic analysis for proofing of D. immitis was car ried out using cytochrome oxidase I (COI) gene. Afterward, the purified DNA was used to determine the molecular pattern of the Wolbachia surface protein (WSP) gene sequence by PCR. Phylogeny and homology studies showed high consistency of the COI gene with the previously-registered sequences for D. immitis. Comparison of DNA sequences revealed no nucleotide variation between them. PCR showed that all of the collected parasites were infected with W. pipientis. The sequence of the WSP gene in Wolbach ia species from D. immitis was significantly different from other species of Dirofilaria as well as other filarial spe cies. The maximum homology was observed with the Wolbachia isolated from D. immitis. The greatest distance be tween WSP nucleotides of Wolbachia species found between D. immitis and those isolated from Onchocerca lupi. PCR could be a simple but suitable method for detection of Wolbachia species. There is a pattern of host specificity between Wolbachia and Dirofilaria that can be related to ancestral evolutions. The results of this phylogenetic analysis and molecular characterization may help us for better identification of Wolbachia species and understanding of their coevolution.

Despite all the efforts made to control and eliminate malaria in Iran, this disease is still considered as a priority health problem in the South East of Iran. We aimed to determine the cultural obstacles which have prevented the elimina tion of malaria in this region. This study was carried out through qualitative content analysis.
Purposeful sampling was done from people who had malaria or were involved with malaria patients in 2015, in Sarbaz City, Sistan and Baluchestan Province, Eastern Iran. Data were collected through interviews using open questions and continued until data saturation. The most important barriers in malaria prevention was delay in visiting health centers, delay in diagnosis and treatment due to superstitious beliefs, lack of information about the disease, misdiagnosis and fake doctors. Other obstacles were lack of trust and cooperation with interventions offered by the health system, lack of proper use of the available facilities to prevent malaria and commuting in the high-risk neighbor countries. Raising awareness in people, officials and health workers about malaria and preventive health interven tions as well as health risks associated with fake doctors, following up and re-examination of peripheral blood smear in suspected cases, establishing malaria control stations in border areas and specific measures to refer immigrants and people crossing the border toward malaria diagnosis stations is suggested.

The aim of study was to compare macroscopical and histopathological findings between venoms be-longing to two scorpion species, Androdoctonus crassicauda, and the newly discovered Leirus abdullahbayrami. The animals used in this experimental study were fifteen New Zealand bred rabbits. Three groups were constituted as group I (L. abdullahbayrami group, n= 6), group II (A. crassicauda group, n= 6) and group III (control group, n= 3). The animals in the L. abdullahbayrami group and the A. crassicauda group were envenomed through an intravenous route. The rabbits were monitored for the first 24h following the envenomation. The animals dead within that time period were examined and all animals were sacrificed and standard necropsy process was performed at 24h. The pathomorphological findings from group I were found to be more severe than those observed in group II. The venom from the newly identified L. abdullahbayrami has a greater effect than the venom from the A. crassicauda. Moreover, as this was a rabbit modeling study, the L. abdullahbayrami might pose the most serious health threat to infants in particular due to their smaller body weight. These findings will provide a better understanding of envenomation of human beings in terms of the possible consequences of scorpion toxication on the organs.

Sandfly fever is an incapacitating disease caused by sandfly-borne Phleboviruses that can lead to men ingitis, encephalitis or meningoencephalitis. West Nile virus (WNV), a mosquito-borne Flavivirus, can induce neu roinvasive disease manifested by meningitis, encephalitis or acute flaccid paralysis. Both vectors are endemic in Cy prus and very active during summer. The aims of this study were to determine first the prevalence of sandfly fever viruses (SFV) and WNV infections in Cyprus and second, to investigate their role in central nervous system (CNS) infections. For the prevalence study, 327 sera collected in 2013 and 2014 were tested for anti-SFV and anti-WNV IgG using indirect immunofluorescence assay and ELISA, respectively. In order to investigate a possible role of SFV and WNV in CNS infections, 127 sera of patients presenting symptoms of SFV or WNV infections were screened for IgM specific to SFV and WNV. The overall anti-SFV IgG seroprevalence was 28% and was increasing with age (P< 0.01). The seropreva lence rate for anti-WNV IgG in Cyprus was 5%. Concerning the role of SFVs in CNS infections, anti-SFV IgM was detected in 8 out of 127 sera from selected patients presenting relevant symptoms of infections during vector’s active period. In addition, anti-WNV IgM were detected in 17 out of the 127 patients with compatible symptoms. The findings confirm the presence of sandfly fever and WNV in Cyprus and should, therefore, be con sidered in the differential diagnosis of patients with febrile illness/meningitis.