Journal of Vector Borne Diseases最新文献

Background objectives: Mosquito-bome diseases are a major health issue among communities in Asia, and dengue has become a serious public health concern in Sri Lanka with varying magnitude since 1960. With the realization of the failures and limitations of current vector control strategies, the authorities are moving towards simple, low- cost, and eco-friendly vector management methods. Thus, the present study was devised to evaluate the potential densities of mosquito natural enemies in natural water habitats in Galle district, Sri Lanka, and to investigate the feeding efficacy of prominent mosquito natural enemies on main dengue vectors (Aedes sp.) in a laboratory setting.

Methods: The survey was carried out using eight sentinel sites in Galle district, and samples of mosquito natural enemies and mosquito larvae were collected, and identified using taxonomic keys.

Results: Study records, the aquatic insects of family Hydrometridae, Belostomatidae, Notonectidae, Nepidae, Ranat- ridae, and Corixidae as dominant mosquito natural enemies, and Libellulidae and Dytiscidae insects as sub-dominant families. The highest density of the family Hydrometridae was recorded in rural, natural inland, and rocky study sites. The order Hemiptera was recorded as the key order of the mosquitos' natural enemies in Galle district. The family Hydrometridae had the highest density of recorded mosquito natural enemies.

Interpretation conclusion: Aedes aegypti and Ae. albopictus were recorded as abundant vector mosquitoes. Family Nepidae is the most effective natural mosquito predator on Ae. aegypti and Ae. albopictus, and this knowledge will be vital for implementing future biological control strategies for Aedes vectors in Sri Lanka.

Background objectives: Mass Drug Administration (MDA) of Di-Ethyl Carbamazine and Albendazole is an effective strategy recommended by the World Health Organization to prevent transmission and eliminate lymphatic filariasis. Under the National Vector Borne Disease Control Programme (NVBDCP) in India, MDA is carried out as a yearly activity in endemic areas to accelerate the progress towards elimination of lymphatic filariasis. The study was carried with the objective to determine the coverage of MDA against lymphatic filariasis among the eligible population in Kalaburagi district, Karnataka and delineate the common reasons for non-acceptance of MDA.

Methods: Field-based cross-sectional survey was carried out. Cluster sampling of 4 clusters (3 rural and 1 urban) from four different taluks (one cluster from each taluk) of the district reporting high, medium and low coverage of MDA (as reported by District Malaria Office) Members from selected households in all clusters were interviewed regarding MDA administration, directly observed treatment, side effects and any co morbidities which ruled out MDA administration. Responses documented as tally marks in assessment sheets shared by NVBDCP office. Proportions, frequencies, and mean were calculated and inferential statistics were used.

Results: A total of 1263 individuals were assessed for MDA from a total 240 households (60 households in each cluster). The coverage of MDA varied from 90.33% in Heerapur in Kalaburagi Urban to 97.87% in Mogala thanda (Chittapur Taluk).

Interpretation conclusion: MDA Coverage against lymphatic filariasis has improved when compared to previous studies and it has also exceeded the coverage threshold as determined by programme for elimination of lymphatic filariasis.

Background objectives: Mosquito vectors are a significant cause of pathogen transmission to both animals and humans. Mosquitoes are responsible for transmitting various diseases, including chikungunya, filariasis, West Nile fever, dengue, malaria, and Zika fever, placing approximately 80% of the world's population at risk of infection at any given time. Controlling mosquitoes has become a multifaceted challenge, influenced by diverse environmental factors such as deforestation, urbanization, and climate change on a global scale. For centuries, medicinal plants have been utilized as bioinsecticides to control insect pests. Ziziphus mauritiana, also known as Chinese apple or Indian jujube is a deciduous thorny tree or shrub. Different parts of the Z. mauritiana plant have been traditionally used to treat various common diseases, a practice still prevalent in India and China.

Methods: In the current investigation, the chemical properties of Z. mauritiana leaf extract were examined through UV-Vis Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), and GC-MS Analysis. Second and fourth instar larvae, as well as pupae, of Aedes aegypti and Culex quinquefasciatus were subjected to different concentrations of the methanolic extract of Z. mauritiana for 24 h and 48 h to assess larvicidal and pupicidal activity.

Results: The FT-IR spectrum analysis revealed the presence of various functional groups in the chemical compounds extracted from Z. mauritiana , including amines, aromatics, alkanes, alkyls, carbonyls, and carboxylic acids. Additionally, GC-MS analysis identified Isoborneol (25.37%), 4-Acetylbutyric Acid (26.82%), and 2-Vinyl- 9-[Beta-D-Ribofuranosyl] Hypoxanthine (24.24%) as the three major phytoconstitutents in the methanol extracts of Z. mauritiana. Regarding the larvicidal activity, the methanolic extract of Z. mauritiana exhibited LC 50 values of 155.67 mg/L and 208.57 mg/L for second instar larvae, and 177.68 mg/L and 252.13 mg/L for fourth instar larvae of Cx. quinquefasciatus and Ae. aegypti, respectively, after 24 h of exposure. For pupicidal activity, the LC 50 values were 502.02 mg/L and 514.99 mg/L on pupae of Cx. quinquefasciatus and Ae. aegypti, respectively, within 24 h.

Interpretation conclusion: Overall, the GC-MS analysis provides valuable insights into the chemical composition of the Z. mauritiana extract, highlighting its potential as a natural and eco-friendly alternative for combating insect vectors and contributing to integrated mosquito management programs.

Background objectives: Aedes aegypti (Linnaeus) is the vector of multiple arboviruses, the most important being dengue viruses (DENV) that causes more than 90 million cases per year. The expanded range of Ae.aegypti into temperate climates has contributed to the increasing risk of DENV to new human populations. As an effort to better understand the ecology of Ae. aegypti in a temperate climate, larval surveillance was conducted to identify oviposition locations of this species from 2016-2018 in two nonincorporated communities located in El Paso, Texas and Ciudad Juarez, Chihuahua, Mexico.

Methods: This survey was conducted inside and outside private residences examining any possible water holding containers to collect with a dipper, turkey baster, or Pasteur pipette. Larvae and pupae were transported to the laboratory and reared to adults for morphological identification. A total of 601 Ae. aegypti larvae were collected and reared to adults from 24 containers in the Sparks community. In contrast, a total of 68 Ae. aegypti were collected and reared to adults from seven containers in the Anapra community.

Results: In both locations, the predominant container type that yielded immature mosquitoes were plastic buckets. Although the results were based on a small sample size, the finding provided a preliminary understanding of the oviposition sites of Ae. aegypti in two urban communities in a temperate climate region.

Interpretation conclusion: The identification of oviposition sites can be used to develop and implement vector control strategies.

Background objectives: Mosquitoes vectors are the key threat that spread viruses, bacteria, nematodes, protozoans, and other infections responsible for the transmission of serious public health ailments including dengue, yellow fever, malaria, and chikungunya.

Methods: To rear and cultivate mosquitoes at multiple stages of development (egg, larva, pupa, and adult) to be employed in various biomedical research, an innovative tool mosquito larva adult 2-in-1 rearing jar was designed and developed. The eggs/larvae or adults collected from the field or laboratory cultures can be released into the lower larvae or upper adult-rearing chamber so that they can find a suitable breeding place to oviposit or metamorphose into wrigglers and tumblers attaining the adult stage. Aedes, Anopheles, and Culex are three significant genera (Diptera: Culicidae) that were reared in experiments using this jar (Method I) in contrast to other conventional instruments available (Method II).

Results: Results of one-way ANOVA showed that the prototype was compatible and competitive for rearing, as the data was non-significant when compared in both groups. However, throughout the trials, it was discovered that the prototype had a greater record of mean percentage of adult emergence (98.33), which supports the novelty of the instrument.

Interpretation conclusion: This unique device eliminates the need for multiple tools, causes minimum bodily damage to stages during handling, can be used in both the lab and the field, is inexpensive, lightweight, portable, and requires single manpower to operate.

Background objectives: Aedes aegypti and Ae. albopictus are two sympatric mosquito species that compete with each other for resources when their breeding habitats overlap. This study examines what happens when sympatric Ae. aegypti and Ae. albopictus mosquitoes' mate with each other and other species by looking at insemination rates, fecundity, and hatchability rate.

Methods: We performed controlled mating experiments in laboratory settings, assessing both conspecific and interspecific crosses. We measured insemination rates, egg numbers, and hatching success to examine the reproductive interference dynamics between these two distinct mosquito species.

Results: In the context of conspecific mating, it was observed that both female Ae. aegypti and Ae. albopictus exhibited high insemination rates, with percentages 98% and 94%, respectively. However, interspecific mating exhibited interesting asymmetries as Ae. albopictus males achieved a notable insemination success rate of 28% when mating with Ae. aegypti females, while Ae. aegypti males achieved only an 8% insemination success with Ae. albopictus females. Additionally, females that mated with interspecific males had reduced production of viable eggs compared to conspecific mating. Most notably, interspecific mating resulted in the production of infertile eggs, while conspecific mating led to successful hatching.

Interpretation conclusion: The study reveals that Ae. aegypti and Ae. albopictus can asymmetrically interfere with each other's reproduction, causing a 'satyr' effect. This understanding of interspecific competition and reproductive interference in these mosquito species could impact their coexistence in shared breeding habitats.

Lyme disease (LD) and tick-bome relapsing fever (TBRF), both consequences of Borrelia burgdorferi infection, pose significant public health threats with overlapping symptomatic presentations. A previous study explores the potential of line immunoblots (IBs) as a transformative diagnostic tool for distinguishing between LD and TBRF. By employing strategically designed recombinant proteins on nitrocellulose membrane strips, IBs offer enhanced accuracy in identifying antibodies in patient samples. While serological assays for LD have seen advancements, the diagnostic landscape for TBRF lags behind, necessitating comprehensive diagnostic approaches capable of addressing both conditions. Immunoblots, with their ability to detect antibodies with exceptional precision, not only facilitate accurate diagnosis but also enable tailored patient treatment and monitoring of treatment response. The study underscores the importance of immunoblots in improving diagnostic accuracy and patient outcomes for tick- borne diseases. In conclusion, as research progresses in understanding LD and TBRF, immunoblots emerge not only as diagnostic tool but also as valuable resources for advancing research and refining patient treatment strategies.

Background objectives: Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease caused by several species of the protozoan parasite Leishmania. The need for new anti-leishmanial drugs for the treatment of CL is complicated by factors such as high cost, toxicity, potential for resistance and limited long-term use of existing anti-leishmanial drugs. The aim of this study was to investigate the therapeutic effect of Tarantula cubensis alcoholic extract (TCE), which has been shown to have wound-healing, anti-inflammatory, regenerative, resolving and epithelialising effects, on Leishmania major promastigotes in vitro and in vivo in an experimental mouse model of CL.

Methods: The effect of TCE on L. major promastigotes in vitro was investigated after determining non-cytotoxic concentrations of TCE using the XTT method. To establish a CL model, L. major amastigotes were injected into the paws of BALB/c mice. Lesion size and histopathological evaluation were used to assess the effect of treatment.

Results: TCE was found to be effective against L. major promastigotes at 24 h and 48 h at concentrations 250 μg/ mL, 125 μg/mL and 62.5 μg/mL ( P <0.05). TCE was found to be more effective than meglumine antimonate in treating CL in the experimentally induced CL model in BALB/c mice.

Interpretation conclusion: The results suggest that TCE holds promising potential as a therapeutic agent for the treatment of CL. However, further extensive investigations are required to substantiate and expand our understanding in this area.

Background objectives: Hantavirus and leptospirosis infections are zoonotic diseases with similar clinical and laboratory findings. The aim of this study is to identify the distinguishing features of these two diseases, for which a definitive diagnosis can take a long time.

Methods: Between September 2021 and June 2023, a total of 45 patients who were admitted to our hospital and were diagnosed with hemorrhagic fever with renal syndrome (HFRS) or leptospirosis were retrospectively evaluated. Patients were compared in terms of demographic data, clinical, and laboratory parameters. The role of these variables in predicting HFRS or leptospirosis was investigated. The two diseases were compared with regard to outcomes. Receiver operating characteristics were employed for the calculation of cut-off values, sensitivity, specificity, and positive and negative predictive values for parameters showing significant differences. A statistical significance level of p<0.05 was considered.

Results: Fifteen patients diagnosed with HFRS and thirty patients diagnosed with leptospirosis were included in the study. In both groups, hospital admissions were observed with non-specific and similar symptoms. There was no statistically significant difference observed between the two groups in terms of length of hospital stay, blood product transfusion, requirement for hemodialysis, intensive care unit admission, the rate of return to normal renal function and mortality. Elevated ferritin levels were statistically significant in favor of HFRS, while lymphopenia, elevated bilirubin, CRP, and ESR were statistically significant in favor of leptospirosis.

Interpretation conclusion: The use of laboratory findings and clinical symptoms can aid in the challenging task of accurately diagnosing and using appropriate treatment for these two diseases.