Journal of Vector Borne Diseases最新文献

Background objectives: Dengue is now endemic in over 100 countries, with Asia bearing over 70% of the global burden. In Malaysia, dengue cases have increased dramatically, particularly in Pulau Pinang, where cases rose from 1,621 in 2022 to 7,343 in 2023. To examine factors associated with dengue outbreaks in Pulau Pinang in 2023 by comparing outbreak cases with single cases.

Methods: Cross-sectional study using eDengue database, the Malaysian National Dengue Registry.

Results: The study included 1,106 confirmed dengue cases, with 553 categorised as outbreak cases and 553 as single cases. Significant associations were found between dengue outbreaks and Priority Locality 1 (areas with Uncontrolled Outbreaks/ Hotspots/ Recurrent Outbreaks/ Dengue Deaths in the previous year) (AOR: 0.15, 95% CI: 0.06,0.37, p<0.001), Aedes Index ≥1% (AOR: 1.35, 95% CI: 1.02,1.77, p=0.031), patients initially visiting government clinics (AOR: 1.63, 95% CI: 1.10,2.43, p=0.015), hospitalized dengue patients (AOR: 0.70. 95%CI: 0.52,0.96, p=0.029), the time taken from notification to source reduction (AOR: 0.57, 95% CI: 0.50,0.66, p<0.001) and time taken from notification to investigation (AOR: 2.40 95%CI: 1.77,3.24, p<0.001).

Interpretation conclusion: This study identifies key factors associated with dengue outbreaks in Pulau Pinang such as Aedes Index, Priority Locality 1 areas and initial visits to government clinics. These findings underscore the need for targeted vector control and early intervention in high-risk areas to reduce outbreak risk. Early healthcare seeking behavior and timely intervention are critical in managing the spread of dengue. Further research is needed to explore additional factors and improve public health strategies.

Background objectives: This study was compared the Borrelia antibodies and chemokine ligand 13 (CXCL13) levels in cerebrospinal fluid (CSF) samples from cases diagnosed with relapsing-remitting multiple sclerosis (RRMS), radiologically isolated syndrome (RIS), and pseudotumour cerebri (PTC).

Methods: A total of 43 CSF samples were collected from patients diagnosed with RRMS, RIS and PTC. We prospectively investigated Borrelia IgG and IgM antibodies in the CSF samples of the cases by enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) method, and CXCL13 levels by ELISA. Data were statistically analysed using the the Spearman rank correlation test.

Results: Five antigens (protein 19, 20, 21, 58, and outer surface protein C (OspC)) were positive due to confirmation of the positive samples for Borrelia antibodies by the WB method. There were no significant differences in CSF CXCL13 levels between the three groups. The CXCL13 level was found to be statistically higher in the demyelinating group compared to the PTC group (p=0.001).

Interpretation conclusion: The Borrelia antibodies were found positive in CSF samples of RRMS patients. The coexistence of high CXCL13 (may be a potential biomarker) suggests that LNB may also play a role in the etiopathogenesis of RRMS. In addition, the positive detection of OspC and p58 WB bands in most cases suggests that these protein bands can be used as in the differential diagnosis of neurodegenerative diseases and Lyme disease.

Background objectives: A hike in dengue cases was recorded in last two years, resulting from both single and multiple-serotypes of dengue virus (DENV) and secondary infections, culminating in significant hospitalizations and deaths in India. This study focuses on evaluating symptomatic and haematological parameters in acute dengue patients of the northern part of West Bengal to predict disease severity early on and also to analyze the correlation between circulating DENV serotypes with severity.

Methods: Dengue patients (N=540) diagnosed as NS1 positives were categorized into 13.7% severe DHF (N=74) and 86.3% mild DF (N=466) and prediction of risk was done using logistic regression. DENV RNA was isolated from blood, converted to cDNA, and detected/serotyped via RT-qPCR by using DENV specific primers.

Results: Only 14.48% (N=11) patients showed single serotypic (DENV2 or DENV3) infection of dengue. In contrast, multi-serotypic infections (N=65) with the prevalence of DENV2 and DENV3 co-infections were found among the dengue patients, affecting severe changes in the most critical haematological parameters such as hematocrit and platelet count. The multivariate binary logistic regression model revealed that only six parameters viz., age (p=0.032), presence of joint pain (p=0.015), Haemoglobin level (p<0.001), total RBC count (p=0.024), total WBC count (p=0.003), lymphocyte% (p=0.019) were found to be significantly associated with the risk of DHF.

Interpretation conclusion: Most prevalent DENV2 and DENV3 infections significantly impact hematocrit and platelet counts in the study region. Our prediction model, incorporating age, joint pain, hemoglobin, RBC, WBC, and lymphocyte, may effectively predict dengue severity.

Background objectives: Sound plays an important role in mosquito foraging and sexual interactions. Mosquitoes utilize acoustic signals for host location, sexual recognition, and mating, which is achieved through the rhythmic beating of their wings to generate distinct sounds characterized by specific flight tone frequencies.

Methods: In this study, electronic music (Tremor by Dimitri Vegas, Martin Garrix and Like Mike) and country music (Country Road by John Denver) were played in high and low volumes to investigate the influence of different genres of music on the blood feeding and mating responses of Ae. aegypti. The observations encompassed monitoring the landing attempts, blood-feeding endeavors, and mating behavior of Ae. aegypti.

Results: High-volume electronic and country music with elevated pitch and amplitude significantly reduced host attacks and blood-feeding attempts by female mosquitoes compared to low-volume or music-off conditions.

Interpretation conclusion: However, the significant reduction of successful copula was only observed in Ae. aegypti mosquitoes exposed under electronic music with high volume. As transmission of dengue is through blood feeding and mating, this discovery may open new possibilities for developing music-based control strategies against mosquito-borne diseases.

Background objectives: A 2.5-year placebo controlled double blind trial was conducted to investigate the safety and efficacy of AYUSH- SL, a poly- herbal Ayurvedic formulation on filarial lymphedema in different endemic areas of India. Lymphatic filariasis (LF) is caused by parasitic nematodes from Wuchereria bancrofti, Brugia malayi, or B. timori that are transmitted through mosquitoes. In Ayurveda, LF has been elaborately narrated under the heading Shlipada, and the literature also includes detailed therapeutic measures.

Methods: The multicenter, prospective, parallel group interventional study of a total of 180 participants were recruited within the duration through competitive enrollment. Diagnosed cases of grade I and grade II filarial lymphedema of Grade I and Grade II (lower extremities) were included in the trial. The study group was treated with MDA and AYUSH-SL or its placebo tablet.

Results: The control group had received MDA and a matching placebo. The primary outcome measure was the reduction in edema calculated for analysis by percentage reduction from baseline at the 4th, 12th and 24th week. Secondary outcome measures included improved quality of life (QoL), which was assessed using the Lymphatic Filariasis Specific QoL Questionnaire, and prevention of recurrence of acute episodes, which was evaluated by investigating the presence and severity of episodes in the past 4 weeks. The water displacement method for the evaluation of the efficacy of the intervention was shown to be highly significant compared to the baseline value (right leg; 3071.60 ± 970.482, 2828.40±829.339, p<0.001and Left leg; 3158.69 ± 1136.391, 2890.73 ±1077.475, p<0.001).

Interpretation conclusion: There was significant improvement of Quality of Life in the LF QoL Questionnaire (p <0.001) at each follow-up visit in both groups. Safety estimations on hematologic and biochemical parameters were within limits and or changes were not significant. The results revealed that AYUSH- SL is safe and effective for FL due to its comprehensive anti-inflammatory, antimicrobial, and anti-allergic activities.

Background objectives: Vector-borne diseases (VBD) are a major public health concern. Globalization, urbanization & climate change are reasons for the emergence and re-emergence of VBDs. In our study, we looked into the prevalence of VBD infections around our tertiary care hospital in South India. The objective was to determine the prevalence of common VBDs like Malaria, Dengue, Japanese encephalitis (JE), Chikungunya and Scrub typhus in patients with acute febrile illness (AFI).

Methods: This was a prospective laboratory based observational study. Blood samples from patients with AFI were tested for Dengue NS1 Antigen, IgM and IgG; and IgM antibodies for JE, Chikungunya and Scrub typhus using ELISA tests. Peripheral blood smear examination was performed for malarial parasite detection.

Results: Total 802 samples were analysed. The sample positivity rate for VBD was 63.6% (510/802 samples) On diving the positive results across seasons in the study period, the VBD positivity rates were 66.3%, 49.1%, 61.2% and 67.3% for the first post-monsoon, summer, monsoon and the second post-monsoon seasons respectively- a trend of increased rates noted during the post-monsoon seasons. 192 samples (23.9%) were positive for scrub typhus alone, 189 samples (23.6%) were positive for dengue infection alone, six samples (0.7%) were positive for chikungunya infection alone, 121 samples (15.1%) were positive for dengue plus scrub typhus co-infection, two samples (0.2%) were positive for dengue plus chikungunya co-infection, while 292 samples (36.4%) showed negative results. None of the samples were positive for malaria and Japanese encephalitis.

Interpretation conclusion: Scrub typhus and dengue were the most prevalent VBDs in concordance with the prevalence pattern noted in other studies in South India. Increasing awareness and surveillance of the VBDs, developing stringent control policies, easy access to testing and initiating early appropriate therapy can help reduce the incidence of VBDs.

Background objectives: To achieve schistosomiasis eradication plan by 2030, the development of efficient diagnosis is crucial. This study focuses on assessing the immunodiagnostic potential of S. haematobium (Sh) soluble egg antigen (SEA) and worm antigen (SWA) for urogenital schistosomiasis.

Methods: Urine microscopy identified 50 S. haematobium-positive and 50 negative samples from a total of 500 examined. An additional 50 samples from a non-endemic area were included, bringing the total number of samples used for the assay to 150. Indirect ELISA immunoassays using SEA and SWA as the probing antigens evaluated 50 sera samples each from Sh positive, negative endemic (NE), and non-endemic (NNE) individuals. SDS-PAGE analysis of crude protein extracts was conducted, followed by Western blot analysis using primary antibodies from pooled Sh-infected sera samples.

Results: Diagnostic performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC), sensitivity, and specificity. The AUC values for Sh SEA and SWA were 0.75 and 0.76 in NE samples, and 0.91 and 0.89 in NNE samples, respectively. Sensitivities 90 (95% CI: 78.64 - 95.65)/ 64.71 (95% CI: 52.17 - 75.92), and specificities 50 (95% CI: 36.64 - 63.36)/ 81.25 (95% CI: 63.56 - 92.79) were recorded for SEA and SWA, respectively in NE samples. In addition, sensitivities 90 (78.64 - 95.65)/ 92 (95% CI: 80.77 - 97.78), and specificities 72 (95% CI: 58.33 - 82.53)/ 72.00 (95% CI: 57.51 - 83.77) were recorded for SEA and SWA, respectively in NNE samples. The mean antibody titer against Sh SEA in infected samples was significantly higher than in non-infected samples (P <0.0001). Eight (8) immunoreactive protein bands; 4 each of SEA and SWA were identified, indicating potential for diagnostic tool development.

Interpretation conclusion: Sh SEA and SWA demonstrate promise for diagnosing urogenital schistosomiasis in both endemic and non-endemic regions.

Background objectives: Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic disease and significant health concern particularly in endemic regions. We aimed to evaluate the efficacy in dexamethasone treatment on clinical outcomes in CCHF patients.

Methods: We included adult patients diagnosed with CCHF and those whose platelet count dropped to 70,000/mm3 or lower. The efficacy of dexamethasone on clinical outcomes was evaluated. It was a retrospective analytical study.

Results: The study included 55 patients. All patients received standard supportive treatment, and none of them received ribavirin therapy. It was observed that 23 (41.8%) of the patients were treated with dexamethasone. No significant differences were observed between patients treated with dexamethasone and those without dexamethasone treatment, regarding factors such as bleeding incidents during hospitalization, the need for blood product transfusions, thrombocyte recovery status, intensive care unit admission, and in-hospital mortality. In-hospital mortality was observed in two patients among all patients (3.6%).

Interpretation conclusion: Our study found that dexamethasone treatment did not lead to a significant improvement in clinical outcomes for CCHF patients.

The epidemiology of dengue has been demonstrating significant changes in recent years, with rising incidence of infection in countries with known endemicity and occurrence of fresh outbreaks in previously unaffected territories. India, which has been a traditional hotspot dengue virus (DENV) transmission in the endemic south-east Asian region, has also been affected by the sweeping changes in dengue epidemiology. Two remarkable developments characterize the alterations witnessed by India 2011-2017. Firstly, all parts of the country have witnessed abrupt replacement of existing DENV lineages with emerging novel strains. Secondly, co-circulation of multiple serotypes of DENV have been reported from all across the country 2011-2017; thereby hinting at the transition of the country towards hyper-endemicity. Considering the potential clinical implications of such epidemiological transformation in terms increasing involvement of pediatric patients and growing predisposition to serious complications, the present review provides an update on the serotypic and genotypic profile of dengue outbreaks that have been witnessed by different zones of India between 2011 and 2017. Dividing the country into northern, southern, eastern, western, central and north-eastern zones, we describe discrete zone-specific distribution patterns of DENV serotypes and genotypes and observe simultaneous circulation of different DENV strains in different parts of the country. Random shifts in the genetic characteristics of the circulating strains and the widespread co- circulation of all four serotypes underscore the need for undertaking continuous and representative molecular surveillance of the circulating DENV strains across the country for prompt identification of emerging strains and novel mutants; gain insights into the formulation of Dengue vaccines and develop a clearer understanding of the molecular basis of immune evasion, disease epidemiology and pathogenesis.

Background objectives: Aedes aegypti is a major vector responsible for spreading dengue, chikungunya, yellow fever, and Zika viruses worldwide. These illnesses have increased globally due to climate and environmental changes. Vector control and management are the principal tactics for combating mosquitoes-borne diseases in the absence of an effective vaccine. The study aimed to ascertain bioactivities of Ageratum houstonianum leaf acetone extract (AhLAE) against Aedes aegypti.

Methods: Bioefficacy of AhLAE was tested against fourth instar larvae (L4) of Ae. aegypti using standard WHO protocol. The mortality, growth, and development of larvae, pupae and adults were recorded after exposure to the extract.

Results: The AhLAE showed larvicidal activity against L4 with LC50 and LC90 values of 401.88 and 691.24 mg/L, respectively. The mortality of the larvae further increased on subsequent days. The AhLAE caused a significant reduction in pupae formation and adult emergence. It also increased the larval duration of L4 and development duration of the pupa formed from the treated L4, indicating its growth-suppressing effects. The impact of the AhLAE was dose-dependent; high concentrations caused reduction in survival and growth of L4. Consequently, the L4-pupal and L4-adult growth indexes decreased. Additionally, the AhLAE induced developmental anomalies in the form of larva-pupa (L-P) intermediates.

Interpretation conclusion: The study found that the AhLAE exhibited larvicidal, growth-suppressing, and development-altering activities against Ae. aegypti. The findings suggest the potential of AhALE as a natural insecticidal agent for controlling mosquitoes.