Journal of Arthropod-Borne Diseases最新文献

Background: The spectrum of dengue infection ranges from asymptomatic or mild to severe disease. The pathogenic mechanisms are not fully understood. A viral infection can induce the neutrophil extracellular traps (NETs), and the excessive NETs lead to increased vascular permeability, coagulopathy, and platelet dysfunction, a hallmark of severe dengue.

Methods: To evaluate the association of NETs formation with disease severity using a human public transcriptomic dataset (GSE17924) and clinical samples from dengue patients with different disease severity.

Results: Based on the transcriptomic analysis, the whole blood gene expression functional in neutrophil activities and NETs formation was upregulated with dengue disease severity. The serum concentration of citrullinated histone H3 (CitH3), a NETs marker, was measured in 28 dengue patients, of whom 18 classified as dengue fever (DF) and 10 as dengue hemorrhagic fever (DHF) grade 1 and 2. A significantly higher CitH3 concentration was found in DHF compared to DF patients. The level of CitH3 was negatively correlated with platelet counts.

Conclusion: Our results suggest NETs have contributed to the disease severity of dengue infection. Future studies on the predictive value of NETs markers and the potential NETs as a targeted therapy in dengue disease should be prioritized.

Background: Coxiella burnetii causes Q fever, a zoonotic and vector-borne disease. Ticks serve as vectors for this bacterium. This study aimed to determine the prevalence of C. burnetii infection in ticks in Shahr-e-Rey County, Tehran Province.

Methods: From December 2016 to November 2017, 179 ticks were collected on sheep at animal husbandry facilities and slaughterhouses located in Shahr-e-Rey, Tehran Province. Tick samples were morphologically identified and evaluated for the presence of the C. burnetii IS1111 gene using real-time PCR.

Results: Ticks were classified into four genera: Hyalomma (66.48%), Rhipicepalus (23.47%), Dermacentor (7.26%), and Ornithodoros (2.79%). Furthermore, 35.20% of the ticks were Hyalomma nymphs.All 77 ticks were pooled by species, and C. burnetii was found in 22.08% (n= 17). Ornithodoros lahorensis was the most prevalent tick infected with C. burnetii.

Conclusion: The distribution of C. burnetii and reports of Q fever from various regions of the country strongly suggest that the monitoring system should give this disease more attention.

Background: Ticks are hematophagous arthropods that have direct and indirect effects on hosts, including the transmission of pathogens. An environmental suitability study of some vector species of hard ticks was conducted using the MaxEnt model in the south-eastern region of the Caspian Sea in Iran.

Methods: The ticks were collected monthly (2014-2015) at 45 study sites covering different areas in terms of topography. Because most farms in the study area are traditionally engaged in sheep production and they are taken to pastures in the warm season, the ticks were sampled from herds of sheep.

Results: In total, 2410 hard ticks were collected and the vector species with wider distributions were considered for modelling. The areas under the curve for Hyalomma anatulicum, Hy. asiaticum, Hy. marginatum, Rhipicephalus bursa, Rh. sanguineus, and Rh. turanicus were 0.848, 0.762, 0.812, 0.772, 0.770 and 0.803, respectively. This means that temperature and precipitation were effective environmental variables for the prediction of appropriate regions for these tick species. The outputs of the models indicated that the western and south- western regions of Golestan Province provided the best niches for the presence of ticks.

Conclusion: The western regions of Golestan Province are potential habitats for tick-borne diseases in both livestock and humans and special attention should be focused on preventing the spread of such diseases in this region.

Background: Considering the importance of scorpions and recognizing the mechanisms of toxicity caused by their medically important species in Iran and adopting the best therapeutic approach based on these mechanisms, this study was performed by reviewing the clinical manifestations of scorpion stings.

Methods: The research was conducted by searching for articles and researches in related websites (PubMed, EMBASE, Scopus, Web of Science and CINAHL) and using domestic and international authoritative journals using the keywords of scorpion, clinical manifestations, in a review method. Finally, 104 qualified sources were selected and after reviewing and criticizing these studies, the author's point of view was presented.

Results: Clinical manifestations of Scorpion sting toxicity vary due to the existence of two toxic classes of neurotoxins and cytotoxins or hemotoxins in these arthropods in Iran. The number and distribution of species with neurotoxic venom are higher than the scorpions with cytotoxic venom and are reported throughout Iran. Scorpions with cytotoxic venom are mostly widespread in south and southwest of Iran.

Conclusion: Treatment and prevention of scorpion stings in Iran and neighboring countries in the Middle East should be planned based on the mechanism of toxicity and the presence of toxic classes with neurotoxic or cytotoxic venoms.

Background: Asymptomatic malaria is a major challenge to be addressed in the implementation of the malaria elimination program. The main goal of the malaria surveillance system in the elimination phase is to identify reliably all the positive cases of malaria reliably (symptomatic and asymptomatic) in the shortest possible time. This study focused on the monitoring of asymptomatic malaria reservoirs in areas where local transmission had been previously established.

Methods: It was a case-study approach that was conducted in the Anarestan area. A total of 246 residents and immigrants living in the area at the age range of 4-60 years old were randomly selected to be tested for malaria by microscope, RDT, and nested-PCR techniques. The inclusion criterion for participants to be entered into the study was the absence of specific symptoms of malaria. Moreover, participants who have been taking antimalarials for the last month were excluded from the study.

Results: The results indicated no positive cases of asymptomatic malaria among the participants tested by all methods.

Conclusion: The results of this study have shown that, without concerns for asymptomatic parasitic patients, a malaria elimination program has been successfully implemented within the studies area. In addition, the findings emphasized the existence of a strong malaria surveillance system in this area.

Background: Larvicidal agents can be produced using microbial resources, which are environmentally friendly, biodegradable, and economical. The study's goal was to evaluate the larvicidal activity of metabolites isolated from Nocardia (N. fluminea, N. soli and N. pseudobrasiliensis) and Streptomyces (S. alboflavus) bacterial species against Anopheles stephensi.

Methods: Four metabolites isolated from Nocardia and Streptomyces strains were exanimated for larvicidal activity. The experiments were performed for 24, 48, and 72 hours. 300, 350, 400, 450, 500, 550, and 600 μl of Actinobacteria metabolites were added to 100 cc of dechlorinated water. Fourth-stage larvae were placed in dechlorinated water as a control. LC₅₀ and LC₉₀ were calculated using toxicity data and analyzed.

Results: All metabolites had a statistically significant influence on mosquito larvae (P< 0.05). At 24, 48, and 72 hours, the LC₅₀ for N2 (N. fluminea) was 417, 386, and 370 ppm, respectively, and the LC₉₀ was 650, 595, and 561 ppm. Moreover, LC₅₀ for N4 (N. soli) was 389, 376, and 347 and LC₉₀ were 591, 565, and 533 and LC₅₀ for N5 (N. pseudobrasiliensis) was 390, 357, and 341 ppm and LC₉₀ were 589, 532 ppm. In addition, LC₅₀ for S921 (S. alboflavus) was 484, 416, and 382 ppm, and LC₉₀ was 701, 612, and 574 ppm.

Conclusion: The four bacterial metabolites tested in our study were found to have a notable effect on the mortality rate of Anopheles stephensi larvae, indicating their potential as natural larvicides. This is an effective technique for controlling Anopheles stephensi that has no detrimental environmental impact.

Background: Reduction of the Aedes aegypti population is the priority effort to control dengue virus transmission including the use of larvivorous fish. Biologically, the predatory efficiency of fish will slow down when the water acidity and temperature change from normal conditions. This study aimed to determine the predatory efficiency of three species of larvivorous fish against the Ae. aegypti larvae in different water temperatures.

Methods: Three well-known species of larvivorous fish namely Poecilia reticulata, Betta splendens, and Aplocheilus panchax were placed into 12 cm diameter jars with three water temperature ranges namely 20-21 °C, 27-28 °C, and 34-35 °C, and allowed to three days acclimatization. As many as one hundred 4^th-instars larvae of Ae. aegypti were gradually entered into each jar, and a longitudinal observation was made at 5, 10, 30, 60, 120, 240, 360, 480, 600, and 720 minutes. The predated larvae were recorded.

Results: In normal temperature ranges, the predatory efficiency of the larvivorous fish was 75%, 72.3%, and 32.8% for B. splendens. Aplocheilus panchax, and P. reticulata, respectively. The predation abilities decreased due to temperature changes. Betta splendens and A. panchax indicated the best predatory efficiency against Ae. aegypti larvae in different temperature conditions.

Conclusion: Betta splendens is the best larvivorous fish in the lower to normal, but A. panchax is the best in the normal to higher temperature ranges. This finding should be considered by public health workers in selecting larvivorous fish to control the Dengue vectors.

Background: Malaria is the most important tropical and parasitic disease in the world. Endophagy of many malaria vectors advocates that impeding their entry into houses and preventing their contact with the occupants from infective bites could protect them against malaria.

Methods: The study was carried out in Jaisalmer District, India and three villages were selected as test villages and three as control. Cross-sectional malaria prevalence surveys and mosquito collections were conducted in all the study villages. Insecticide-treated nets (ITNs) were tied below the beds for personal protection against the mosquito bite. Door and window curtains along with partition curtains were treated with insecticide for baring the entry of mosquito vectors.

Results: Plasmodium vivax and P. falciparum were reported from the study villages. Higher malaria cases were detected in the control villages than the insecticide-treated bed net-distributed villages. The percentages of reduction of mosquito density in the houses of the ITNs distributed villages were significantly higher than the control villages. The insecticide activity was decreased slowly, and the knockdown time (KD₅₀) values were found to be increased with the duration of usage of net. The KD₅₀ of Anopheles subpictus s.l. was found to be more than the An. stephensi. Rooms where the ITNs were found to be significantly lower per man-hour density of mosquitoes.

Conclusion: The use of alternative forms of ITNs shows a potential for preventing malaria and are making a significant contribution to the mosquito control. Effective use of ITNs could be helpful in the malaria elimination in India by 2030.

Background: Bed bugs (Cimex lectularius) are blood-sucking insects that bite humans usually at night and cause nuisance, psychological and social problems. These insects are considered a health hazard in densely populated places such as prisons. The aim of this study was to evaluate the knowledge, attitude and practice of inmates, soldiers, and prison staff regarding bed bugs in Mazandaran prisons.

Methods: This is a descriptive-analytical study in which 450 inmates and 210 staff (105 personnel and 105 soldiers) from prisons of Mazandaran Province were included in the study. Data on knowledge, attitude, and practice of the participants regarding bed bugs were collected using a structured questionnaire. To determine the relative content validity coefficient, the questionnaire was assessed by 10 specialists in terms of difficulty, inappropriateness, and ambiguity of the phrases. The reliability of the questionnaire was measured using Cronbach's Alpha and then the data were analyzed using SPSS software version 20.

Results: The maximum mean scores of knowledges, attitude, and practice between the three target groups were 16.42%, 44.07% and 71.21% respectively. Prison staff had the highest knowledge and practice, and inmates showed the highest attitude regarding bed bugs. There was no significant difference between the knowledge and attitude of inmates, prison staff and soldiers (P> 0.05) but there was a significant difference in their practice (P< 0.05).

Conclusion: Results of this study confirmed that all three groups of people in the prisons need appropriate education regarding all aspects of bed bug including its control.

Background: Understanding the microbiota of disease vectors can help for developing new strategies to prevent the transmission of vector pathogens. Ixodes ricinus is one of the most notorious tick vectors with increasing importance in Iran and other parts of the world while there is limited data on its microbiota. This study aimed to use metagenomics for identifying the I. ricinus tick's microbiota of Iran.

Methods: A total of 39 adult ticks were collected from Mazandaran (21 females), Gilan (17 females), and Golestan (1 male). Five tick pools prepared from 39 adults of I. ricinus were subjected to metagenomics analysis. The data were analyzed by targeting the V6 region of the 16S rRNA gene by Illumina 4000 Hiseq sequencing.

Results: Among hundreds of intestinal microbiota identified by metagenomics, various pathogenic microorganisms distributed in 30 genera and species including those responsible for tick-borne diseases resided in the genera Coxiella, Rickettsia, and Burkholderia were found.

Conclusion: Our results indicated that metagenomics identifies bacteria genera and species which cannot be easily recognized by routine methods. The presence of such pathogenic bacteria indicates the importance of possible zoonotic diseases in this region which could affect public health. These results further substantiate the importance of advanced metagenomics analyses to identify neglected tick-borne pathogens which enable researchers to provide efficient mapping roads for the management of emerging and re-emerging infectious diseases.