Journal of Arthropod-Borne Diseases最新文献

Background: The growing concerns regarding the recent invasion of Aedes aegypti in Iran and the potential outbreak of dengue fever, chikungunya and Zika viruses in the country highlight the importance of assessing the susceptibility of this vector to different insecticides.

Methods: The study assessed the resistance status of Ae. aegypti resistance to insecticides such as deltamethrin, permethrin, malathion, and temephos in Bandar Abbas City, Hormozgan Province, Iran. The research followed WHO standard testing procedures for adult mosquitoes. Adult susceptibility tests were conducted using 1X the discriminating concentrations to determine the frequency and status of insecticide resistance. Additionally, 5X and 10X the discriminating concentration were used to evaluate the intensity of resistance. Larval susceptibility to temephos was tested using concentrations of 156.25, 31.25, 6.25, 1.25, and 0.25 mg/l of temephos.

Results: Adults were resistant to all three tested insecticides at WHO-recommended diagnostic concentrations (DCs). In terms of resistance intensity, Ae. aegypti exhibited low-intensity resistance to malathion and deltamethrin, while resistance to permethrin was high-intensity. Dose-response analysis regarding the susceptibility of larvae to temephos showed LC₅₀, LC_90, and LC₉₉ values of 0.013, 0.065, and 0.238 mg/l, respectively. These values indicate resistance when compared to the WHO diagnostic dose for temephos resistance of 0.012 mg/l.

Conclusion: The results of this study highlight the need for an urgent strategy to manage resistance to insecticides and strengthen the integrated management program of Ae. aegypti. This fact emphasizes the importance of reducing larval sources and promoting research on alternative methods and products.

Background: Cutaneous leishmaniasis (CL) is a neglected tropical infection and the most prevalent vector-borne disease in Iran. There is no approved human vaccine and current treatments are restricted; some drugs are expensive and have notable side effects. Therefore, the need for the development of a safe and effective vaccine that can be produced at a low cost remains urgent. It has been shown that vaccinating animals with salivary gland homogenate or saliva components of sand flies protected against Leishmania infection. In this study, we aimed to prepare a mammalian expression vector encoding Phlebotomus papatasi salivary protein 15 (PpSP15) intended to be used as a DNA vaccine in our forthcoming studies.

Methods: In this study, we designed and constructed pcDNA3. 1, a constitutive mammalian expression vector, to encode the immunogenic protein PpSP15. The presence of the target gene was confirmed by enzymatic digestion and sequencing. The mammalian COS-7 cells were transfected with the pcDNA3.1 vector and the expression of PpSP15 protein was then examined in the cell line using Western Blotting analysis.

Results: Restriction enzyme digestion and sequencing revealed the correctly constructed pcDNA3.1-PpSP15. After the transfection of the COS-7 cell line with pcDNA3.1-PpSP15 using Linear Polyethylenimine, the PpSP15 protein expression was confirmed by western blot analysis using anti-His antibody.

Conclusion: A high expression level of PpSP15 protein in COS-7 cells was achieved after the transfection of COS-7 cells, using cationic Linear Polyethylenimine. In subsequent research, this recombinant plasmid is supposed to be utilized as a candidate DNA vaccine to find its immunity induction in susceptible animal models.

Background: Anthroponotic cutaneous leishmaniasis (ACL) caused by Leishmania tropica is endemic in most parts of Iran; however, its vector ecology has not been extensively studied. This study investigates the effects of lunar phases and climatic factors on the biodiversity and frequency of sand flies in various biotopes, with and without artificial light.

Methods: Sand flies were collected using sticky paper traps in four lunar phases (new moon, first quarter, full moon, and last quarter). Alpha and beta diversity indices were calculated using the relevant formulas. Poisson regression analysis was used to study the relationship between lunar phases and climatic factors with the sand fly frequency.

Results: In places with artificial light, the highest richness was observed in the new moon and the first quarter (S= 7), and the highest species evenness and Shannon-Wiener indices were observed in the last quarter (E= 0.464, H= 0.832) phases. But in areas without artificial light, the maximum value of richness was in the first quarter and full moon (S= 9), and the highest value of evenness and Shannon-Wiener was in the first quarter (E= 0.748, H= 1.645). Non-parametric tests revealed that among climatic factors, only wind speed exhibited a significant correlation with sand fly frequency.

Conclusion: The highest diversity in biotopes with and without artificial light was observed in the last quarter and first quarter, respectively, and also, wind speed influenced the frequency and diversity of sand flies in different habitats, so in sand fly surveillance, it is crucial to consider these important factors.

Background: As medical students are the future doctors and healthcare providers of the country, it is essential to evaluate their awareness, attitude, and practice about leishmaniasis. Therefore, we have decided to assess the knowledge, attitude, and practice of medical students in the clinical phase about cutaneous leishmaniasis (CL).

Methods: This descriptive-analytical study was performed on 318 clinical students, including those in physiopathology, Extern-1, Extern-2, and internship phases at Golestan University of Medical Sciences. A questionnaire was designed, containing 28 questions divided into four sections: demographic, knowledge, attitude, and practice. Data were analyzed using the Spearman correlation coefficient and Chi-square tests.

Results: 318 individuals participated in the study, of which 193 (60.6%) individuals were female, and 125 (39.4%) individuals were male. 70 physiopathology students (100%), 72 Extern-1 students (93.5%), 73 Extern-2 students (92.4%), and 88 internship students (100%) had a good level of awareness. Among physiopathology students, 42 individuals (60%), 58 Extern-1 students, (75.3%), 71 Extern-2 students, (85.5%), and 88 (100%) internship individuals had a good attitude. The results of this research showed that 19 (27.1%) physiopathology students, 49 (63.6%) Extern-1 students, 27 (32.5%) Extern-2 students, and 42 (47.7%) interns had a good level of practice.

Conclusion: As future healthcare providers, medical students must possess a high level of knowledge, a positive attitude, and strong practice skills in managing conditions such as CL. Given the prevalence of this disease in the country, organizing targeted educational programs for medical students can significantly enhance their knowledge and abilities.

Background: The extract of seed and leave of Ricinus communis (castor plant) is rich in glycerides and fatty acids, including ricin, oleic acid, palmitic acid, linoleic acid and dihydroxy-stearic. This study aimed to evaluate the repellency effect of R. communis leaf extract (castor extract, CE) on Phlebotomus papatasi sand flies and compare its effectiveness with a commercial insect repellent, 10% DEET spray (positive control), under laboratory conditions.

Methods: Hydro-alcoholic extract of castor leaves was prepared, and the repellency effect and mortality rates were evaluated at different doses. The study also assessed 10% DEET (positive control) and 50 μl of 70% ethanol (negative control). The modified Wirtz method was applied using the K and D apparatus.

Results: The repellency effect of various doses of hydro-alcoholic castor extract (CE) on Ph. papatasi sand flies were evaluated. The ED₅₀ (95% CL) was calculated as 4.17 mg/cm², and ED₉₀ (95% CL) as 7.9 mg/cm² after 24 hours of exposure. At 1.6 mg/cm², the repellency effect of hydro-alcoholic CE was greater than that of 10% DEET. However, DEET exhibited higher repellency than CE at concentrations below than 1.6 mg/cm² (i.e. 0.1, 0.2, 0.4 and 0.8 mg/cm²). Mortality among sand flies was observed only at high doses (1.6mg/cm²) of hydro-alcoholic CE, with the highest mortality rate recorded at 17.7%.

Conclusion: This study demonstrated that 10% DEET and hydro-alcoholic castor extract exhibit strong repellency effects against Ph. papatasi sand flies, the primary vector of zoonotic cutaneous leishmaniasis. The findings highlight castor extract's potential as an effective sand fly repellent.

Background: Golestan National Park is the first, oldest and most vast national park in Iran. It was registered as a biosphere reserve by UNESCO in 1977. The park is located in Golestan, North Khorasan and Semnan Provinces. There is no information about the mosquitoes (Diptera: Culicidae) in this park.

Methods: The larvae of mosquitoes were captured from various habitats using the standard 350 ml capacity dippers and also by pipettes, for small larval breeding sites, and buckets, for wells, during spring-autumn 2019. Larvae were preserved in lactophenol and mounted on microscope slides in Berlese medium and identified by morphological characters. The altitude and coordinates of the sampling localities, larval habitat characteristics and physicochemical features of habitat waters were recorded. Association and affinity indices were calculated.

Results: In total, 1349 larvae including 13 species across four genera were collected: Anopheles claviger, An. maculipennis s.l., An. moghulensis, An. superpictus s.l., Culex hortensis, Cx. perexiguus, Cx. pipiens, Cx. theileri, Cx. torrentium, Cx. tritaeniorhynchus, Culiseta longiareolata, Cs. subochrea and Uranotaenia unguiculata. Anopheles moghulensis and Cx. torrentium were new to the region. Culiseta longiareolata (62.6%) displayed the most abundance. Anopheles maculipennis s.l., An. moghulensis and Cs. subochrea were the least specimens (0.1%). Larval habitat characteristics, physicochemical features of habitat waters, association occasions, and percentages were presented. The nitrate of water samples displayed a significant difference among the species (P=0.003).

Conclusion: The study of bionomics of adult mosquitoes and detection of the vectors of different pathogens using serological or molecular-specific tests are recommended.

Background: Anaplasma spp. and Ehrlichia spp. are amongst the most important tick-transmitted bacteria that can cause zoonotic disease in various hosts including ruminants and humans.

Methods: In this study, 16srRNA, EE, and dsb sequences were respectively used to screen Anaplasmataceae family, Anaplasma spp., and Ehrlichia spp. in tick samples (n= 100) collected from 100 domestic ruminants including 50 sheep and 50 cattle in Jiroft City, southeast of Iran, between June and August 2021.

Results: two genera were predominant among the ticks including Hyalomma spp. (64%; 43% from sheep and 21% from cattle) and Rhipicephalus spp. (36%; 22% from cattle and 14% from sheep); all ticks were adult and 73% of them were male. DNA of Anaplasmataceae was detected in 17% (17/100) of the ticks collected from cattle (18%; 9/50) and sheep (16%; 8/50). Anaplasma spp. was not found in the samples, but two ticks were positive for Ehrlichia spp.; all were positive for Ehrlichia spp. belonged to the cattle (4%; 2/50).

Conclusion: This study shows that Anaplasmataceae strains are circulating via ticks among domestic ruminants in the study area, emphasizing the need for effective tick control strategies by livestock farmers, health, and veterinary authorities. Surveillance, molecular characterization and further sequencing-based studies are crucial for informed control and prevention efforts.

Background: Zoonotic cutaneous leishmaniasis (ZCL) is an endemic disease in Varzaneh City where Leishmania major is the causative agent and the great gerbil, Rhombomys opimus, is the main reservoir host of the disease. Despite control efforts, ZCL outbreaks recur every few years. This study was conducted to revive information on the parasite/s species circulating between humans and the reservoirs in the region.

Methods: Leishmania infection in patients and R. opimus was studied using direct parasitological and molecular methods during 2019-2021. Nested-PCR and DNA sequencing were used for Leishmania parasite identification. Inter and intra-species variations in the Leishmania parasites were investigated using BLAST and MEGA7 software.

Results: All suspected patients (N=34) and 14 out of 36 great gerbils tested positive for Leishmania parasites via direct parasitological method. Nested-PCR method revealed all the patients were infected with L. major (94.1%) and mixed infection of L. major and Leishmania turanica (5.9%), and great gerbil specimens were infected with either L. major (44.4%), L. turanica (5.6%), or Leishmania gerbilli (5.6%) and also with mixed infection of L. major and L. turanica (30.5%), L. major and L. gerbilli (8.3%) and mix of all the three Leishmania species (5.6%).

Conclusion: The identical sequences of L. major in both human patients and rodents indicate that the great gerbils are the main reservoirs of L. major in Varzaneh City. The presence of L. turanica in patients would be of interest to carry out further studies to determine the role of this species in the persistence, signs, and treatment of ZCL in humans.

Background: The global rise in malaria parasite resistance to antimalarial drugs necessitates new therapeutic strategies. Medicinal plant extracts, long used in traditional malaria treatment, have shown antiplasmodial potential in recent studies. This study investigated the effects of nano tannic acid MgO (NTA MgO) and chloroquine (CQ), both individually and in combination, on a chloroquine-sensitive Plasmodium berghei strain.

Methods: BALB/c mice infected with P. berghei were divided into 11 groups. Groups were treated with NTA MgO (12.5, 25, 50, 100 mg/kg), CQ (1, 3, 10, 20 mg/kg), pure tannic acid (100 mg/kg), or assigned as controls. Peter's method determined the fifty percent effective dose (ED50) for NTA MgO and CQ. Drug interactions were assessed using the fixed-ratio method (ratios: 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, 0/100). Parasitemia and inhibition percentages were calculated and analysed using SPSS software.

Results: The ED₅₀ values for CQ and NTA MgO were found to be 1.1 mg/kg and 25 mg/kg, respectively. A synergistic effect was observed when a combination of 30% CQ and 70% NTA MgO was used, which significantly reduced parasitemia compared to the control group (P< 0.05, Kruskal-Wallis test). Additionally, NTA MgO administered alone at a dosage of 25 mg/kg effectively reduced the parasite load.

Conclusion: NTA MgO showed strong antiplasmodial activity both alone and with chloroquine (CQ). The 30% CQ and 70% NTA MgO combination exhibited a significant synergistic effect, highlighting its potential as a new treatment for chloroquine-sensitive malaria and the promise of plant-based nanoparticles against drug-resistant malaria.

Background: Venom of scorpions are complex bioactive polypeptides. To gain greater insights into the structural and functional impacts of toxins from Androctonus crassicauda (Buthidae), a dangerously venomous scorpion species, its venom was isolated, purified, and characterized.

Methods: Long chain toxin with four disulfide bonds purified by size exclusion chromatography and reversed-phase HPLC and characterized by amino acid sequencing and molecular weight determination.

Results: The primary structure analysis exhibits a neurotoxin named AnCra2 with 7302.24 Da molecular weight and 64 amino acid residues that cause paralysis and lead to death in NIH mice. The LD₅₀ of AnCra2 was determined to be 0.61±0.04 μg/mice. Phylogenetic analysis displays the toxin has 97% sequence similarity with alpha toxins reported from north African scorpions that affect voltage-gated sodium channels (VGSC), also proposed that differentiation among the scorpions of family Buthidae is affected by the geographical conditions and efficiency in evolutionary variations. AnCra2 exposed binding residues have a high affinity for receptor residues in site-3 (segment-3) of VGSC that are approved by three-dimensional structure and homology modeling.

Conclusion: Purified AnCra2 seems to be a new putative Alpha neurotoxin in homology with the structure of neurotoxins that act on VGSC as a pharmaceutical tool.