Journal of Vector Borne Diseases最新文献

Background objectives: Vector-borne diseases, particularly mosquito-bome illnesses, cause significant global health challenges, leading to approximately 700,000 deaths annually. In India, malaria remains a critical issue, especially in regions like Odisha state, where climatic factors heavily influence transmission dynamics. The study aimed to investigate the correlation between climatic factors (rainfall, temperature, and humidity) and malaria transmission in Kalahandi district of Odisha, India. This work focuses on understanding how local weather conditions affect mosquito breeding, population dynamics, and malaria incidence.

Methods: Epidemiological data from 2019 to 2021 on malaria cases was collected from the Chief District Medical Officer's office in Kalahandi. Entomological data were gathered bimonthly by capturing mosquitoes from various locations in Kalahandi using standard methods. Meteorological data, including monthly rainfall, temperature, and humidity, were obtained from the Odisha government database. The data were analyzed using correlation analysis, linear regression, and Pearson correlation to explore the relationship between weather parameters and malaria cases.

Results: The study found that rainfall positively correlates with malaria incidence, particularly during peak rainy seasons (July to September). Plasmodium falciparum cases showed a strong association with precipitation, while temperature and humidity showed mixed results. Excessive rainfall, however, may disrupt mosquito breeding sites.

Interpretation conclusion: It was noticed that Anopheles culicifacies was prevalent year-round but was particularly dense during the winter and summer (pre-monsoon) seasons, often in conjunction with Anopheles fluviatilis . The findings highlight the complex interplay of climatic factors influencing malaria transmission in the region, with rainfall being the most significant driver.

Background objectives: Dengue, a fast-growing vector-borne disease, has an estimated case-fatality rate of 5% and India is largely affected by dengue. Due to its unpredictable course and non-availability of specific treatment, timely identification of risk factors of severe dengue and its management is crucial. This study aimed to evaluate the clinical profile of children admitted to a tertiary care hospital with dengue, including their outcome, and identify the risk factors for severe dengue.

Methods: This prospective observational study included children admitted with serologically confirmed dengue. World Health Organization classification was used to classify the illness. The details of demographic characteristics, history, clinical examination, laboratory parameters, and outcome were noted. Various risk factors associated with severe dengue, including clinical and laboratory parameters, were determined using crude and adjusted odds ratios at 95% CI.

Results: Out of 157 enrolled children, 51 (32.5%) had severe dengue, and 5 (3.2%) died. Severe dengue showed no predilection for age, gender, or baseline IgG positivity. Multivariate-logistic regression analysis identified only fever ≥39°C [aOR 4.06 (1.60-10.27)] and petechiae [aOR 9.91(3.07-32.03)] as the clinical risk factors for severe dengue. Prolonged prothrombin time (>14s) [aOR 37.21(1.46-946.23)] and platelet count less than 50,000/cu mm [aOR 12.83(1.12-147.17] were observed as independent laboratory risk factors for severe dengue.

Interpretation conclusion: Simple clinical measures like a detailed history of fever >39°C and examination, especially for petechiae, should caution clinicians against progressing to severe dengue. Along with platelet count, prothrombin time should also be monitored during laboratory investigations.

Toxic epidermal necrolysis (TEN) and Steven-Johnson syndrome (SJS) are rare, severe cutaneous reactions often triggered by drug hypersensitivity. These conditions, characterized by varying degrees of skin detachment, are associated with certain medications, particularly antiepileptics and antibiotics. Chloroquine, a widely used antimalarial drug, is generally considered safe, but rarely, it can lead to TEN. We present a case of a three-year-old boy who developed TEN after oral administration of chloroquine for suspected malaria. Despite intensive care, the child experienced complications and eventually succumbed to the consequences of TEN. This case underscores the importance of recognizing the potential life-threatening side effects of chloroquine, especially in regions where it is frequently prescribed, like India. Healthcare professionals should remain vigilant about rare yet severe adverse reactions associated with widely used drugs like chloroquine.

Background objectives: India has made significant progress in combating malaria and reducing malaria-related mortality and morbidity. Yet, local transmission and malaria hotspots are important hurdles as India looks to achieve malaria elimination by 2030. Gadchiroli district is a highly malaria-endemic area in Maharashtra state of India. It accounts for more than 50% of the reported malaria cases in the state. Anopheles culicifacies and An. fluviatilis are the primary malaria vectors in the area. However, the status of vector sibling species is unknown in the district. In this study, we aimed to identify the sibling species of An. fluviatilis present in the district.

Methods: An. fluviatilis were collected from the human dwelling of the Dhanora block of the Gadchiroli district. The anopheline mosquitoes were identified morphologically and dissected for detachment of the head and thorax. Sibling species, Incrimination investigations, and analyses of blood meal sources were conducted using polymerase chain reaction (PCR).

Results: Two sibling species of An. fluviatilis S and U were present in the study area. Sibling species S was more prevalent than sibling species U. An. fluviatilis S was found to ingest human blood meal. An. fluviatilis U was feeding on cattle. Nevertheless, none of the samples were found positive for sporozoites or oocysts.

Interpretation conclusion: The propensity for malaria transmission varies across sibling species of An. fluviatilis. An. fluviatilis sibling-species S is more prevalent in the Gadchiroli district than sibling species U. The sibling species S was reported to play a major role in malaria transmission in central India. An. fluviatilis S feeds on humans and sibling species U was found to be more zoophilic. The resting behaviour of both these species was in human dwellings and it can enhance interaction with sprayed walls. Consequently, to achieve malaria elimination it is imperative to conduct a study of vector bionomics at the sibling species level to designate the most suitable vector control tools.

West Nile virus (WNV) infection is emerging as a disease of public health concern in Kerala state, India with recurring outbreaks since 2011. With its tropical climate, biodiversity hot spots of Western ghats, forest cover, plenty of water bodies and bird sanctuaries, Kerala provides an ideal ecological niche for vector breeding and transmission of WNV. In this work, we reflect on the peculiar features of the outbreaks of WNV fever in Kerala and highlight the knowledge gaps, research priorities and the need for effective control measures. Information on transmission patterns of WNV, its circulating lineages and identification of vectors is needed to adopt appropriate control strategies in the state. In addition to the active measures on the part of the health system to ensure vector control and to curtail transmission pathways of the disease, inclusion of the community in preventing WNV infection through awareness campaigns and other participatory control measures should be initiated in the pre-monsoon months.

The Japanese Encephalitis Virus (JEV), a zoonotic flavivirus, is responsible for infecting humans and inducing reproductive complications in swine, with transmission primarily facilitated by mosquitoes. Predominantly observed in Southeast Asia, Japanese encephalitis (JE) primarily circulates between amplifying hosts, notably swine, and culicine mosquitoes, particularly Culex tritaeniorhynchus . The wading birds are the reservoir host of this disease. Utilizing real time polymerase chain reaction (RT-PCR) presents a potential approach for detecting JEV in mosquito populations. Manifesting primarily within the central nervous system, JEV infection can instigate severe inflammation, contributing significantly to mortality rates, notable in India, especially in Uttar Pradesh, where JE poses a substantial public health concern. The initial instances of JE in Indian territories were recorded in 1955 in the southern provinces of Vellore and Puducherry, and in 1978 in the northern regions. Uttar Pradesh, among the 24 states endemic to JE, accounted for over 75% of reported cases till 2021 and remained as the state with highest JE cases uptill 2017. The geographical landscape of Gorakhpur, characterized by low topography, susceptibility to flooding, heavy precipitation, paddy cultivation and silt accumulation in riverbeds, creates favorable conditions for mosquito breeding and subsequent JEV transmission. Recent data from India's National Centre for Vector Borne Diseases Control (NCVBDC) indicates a decline in acute encephalitis syndrome (AES) and JE cases in Uttar Pradesh including Gorakhpur which has been the hot bed for JE/AES. Effective coordination across diverse sectors supported by evidenced based research by Indian Council of Medical Research (ICMR) in Gorakhpur played an important role under comprehensive multi-sectoral "One Health Approach", which helped significantly in mitigating the disease burden with more than 90% reduction in morbidity and mortality. This article assesses the current scenario, key intervention measures, ongoing initiatives, and underscores the significance of adopting a One Health Approach in combating JE/AES as a "Gorakhpur experience" to be implemented in other parts of the country and elsewhere.

Background objectives: Vector-borne diseases (VBDs) are a major public health concern. Globalization, urbanization and climate change are the reasons for the emergence and re-emergence of VBDs. In this study, we looked into the prevalence of VBD infections around a 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 and the sample positivity rate for VBDs was 63.6% (510/802 samples). On dividing 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, six samples (0.7%) were positive for chikungunya infection, 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 JE.

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 VBDs, developing stringent control policies, easy access to testing and initiating early appropriate therapy can help reduce the incidence of VBDs.

Background objectives: Mosquitoes transmit malaria and other infectious diseases. A thorough understanding of the dynamics, biting behavior, and infectiousness of Anopheles vector sporozoites is required to calculate transmission indices and develop effective control tactics. The goal of this study was to identify the mosquito species in a rural settlement near the Osogbo city in southwestern Nigeria, as well as their sources of blood meals and the rate at which sporozoites are formed.

Methods: From June to December 2021, 23 homes in the community were chosen at random to catch adult mosquitos with CDC light traps and pyrethrum spray catches (PSC). Mosquitoes were sorted using morphological criteria, and polymerase chain reaction (PCR) was used to detect the origin of the blood meal, check for the infectivity of sporozoites in the mosquitoes, and calculate the fraction of Anopheles gambiae s.l . collected.

Results: Among the 318 mosquitos collected, 185 (58.18 %) were recognized as An. gambiae s.l ., four (1.26 %) as Aedes aegypti , 104 (32.70 %) as Culex quequinfasciatus , and 25 (7.86 %) as Mansonia uniformis . PCR revealed that the specimens of An. gambiae s.l . were 96% An. colluzzi and 4% An. gambiae s.s. An. colluzzi mosquito species only consumed human blood.

Interpretation conclusion: The presence of sporozoites in none of the An. gambiae s.l . mosquitoes in the area indicates a low rate of malaria transmission. The anthropoliphic nature of the Anopheles species implies a danger of malaria transmission, despite the fact that none of the people tested positive for sporozoites.

Background objectives: Kyasanur forest disease (KFD) is a tick-bome viral illness prevalent in the Western Ghats region of India, posing a significant public health concern. The current formalin-inactivated KFDV vaccine exhibits modest efficacy, necessitating the development of more potent preventive measures.

Methods: This study employed immunoinformatic modelling techniques to design a multiepitope-based vaccine subunit targeting humoral and cell-mediated immune responses against KFDV. The vaccine was constructed using helper T cell (CD4+), cytotoxic T cell (CD8+), and B cell epitopes, linked together with appropriate linkers and an adjuvant β-defensin at the N-terminus, resulting in a 704 amino acid long vaccine subunit. Evaluation parameters included immunogenic potency, allergenicity, solubility, toxicity, and population coverage. Predictions of secondary and three-dimensional (3D) structure were made, followed by docking studies with Toll-like receptor-3 (TLR3) and major histocompatibility complex (MHC-I and II) to assess binding affinity. Additionally, simulation of the vaccine and TLR3 construct was performed using the iMod server to further analyze their interaction dynamics.

Results: The developed vaccine subunit exhibited favorable structural and dynamic stability, with strong binding affinity to target receptors. Codon optimization and in silico cloning analysis indicated high vaccine expression and potency. Immune stimulation studies revealed enhanced production of IgG, IgM, helper T cells, cytotoxic T cells, INF-gamma, and IL-2, indicative of robust immune response against KFDV.

Interpretation conclusion: The developed vaccine construct was structurally and dynamically stable and produced a strong immune response against KFDV. However, further animal model studies are needed to assess the efficacy and safety of these vaccines for the prevention of KFDV The vaccine subunit structure was submitted to the ModelArchive database.