Journal of Vector Borne Diseases最新文献

The Chandipura virus (CHPV) is an emerging arbovirus in India, transmitted primarily by sandflies and associated with outbreaks of acute encephalitis in children. First identified in 1965 in Maharashtra, CHPV has since been linked to Acute Encephalitis Syndrome (AES) in several states, including Maharashtra, Gujarat, Telangana, and Madhya Pradesh. The virus predominantly affects children under 15 years, particularly in rural areas with poor housing conditions, and is most prevalent during the monsoon season when sandfly activities are high. Its clinical presentation includes a rapid-onset febrile illness progressing to encephalitis, often with a high case fatality rate. Diagnostic challenges arise due to similarities with other arboviral infections, complicating outbreak management. Current public health interventions emphasize vector control, environmental sanitation, and community awareness, though the lack of specific antiviral treatment and vaccines remains a significant barrier. This review highlights the need for improved surveillance, diagnostic tools, and vaccine development to mitigate the potential public health impact of CHPV in India. A One Health approach, integrating human, animal, and environmental health, is crucial for the effective management and prevention of CHPV outbreaks.

Background objectives: Visceral leishmaniasis (VL, or Kala-azar) is a potentially lethal vector-borne disease caused by intracellular protozoa of the genus Leishmania , serves as the primary reservoir; traditionally endemic to Bihar, Jharkhand, West Bengal, and Eastern Uttar Pradesh Indian states along river belts. VL has recently been observed in the past few years at a tertiary care teaching hospital located in the Himalayan region (non-endemic state, Uttarakhand). This study was done to identify the clinical features, demographics, complications and the risk factors involved in patients of non-endemic region a tertiary care hospital.

Methods: This retrospective study with present-day follow-up of all patients was done on VL patients who were admitted from January 2018 to January 2024. Diagnosis was established by rK 39 antigen test and/or Leishman-Donovan (LD) bodies on bone marrow examination. The clinical and laboratory data, duration of hospital stay and outcomes, and associated risk factors were collected on a proforma and analysed. Factors associated with Himalayan region (Uttarakhand) above Rishikesh (>1120 feet from sea level) were analysed using Chi-square.

Results: Males constituted 92% of the study population from which 67% of the population was from the Himalayan region of this middle Southern Himalaya (Uttarakhand). Risk factors such as residence in the rural area (p=0.47), residence near vegetation (p=0.12), poor household characteristics (p=0.073), low educational status (p=0.073), nearby water body (p=0.073), poor sewage or garbage disposal (p=0.241), insect bites (p=0.040) were associated with Himalayan region emergence. Fever (100%) and malaise (100%) were the most common symptoms presented followed by pain abdomen (29%). Pallor (100%) and splenomegaly (100%) were the most common abnormalities identified on examination followed by hepatomegaly (83%). Anemia (100%) and leukopenia (100%) were the most common biochemical abnormality detected followed by thrombocytopenia (79%), acute liver injury (63%), and hemophagocytic lymphohistiocytosis (HLH) (58%). The disease was diagnosed by the rK39 antigen test (67%), LD bodies in bone marrow examination (67%) and both positive in 29% patients. Mortality was seen in 17 % patients secondary to sepsis (75%) and one case post-discharge due to unknown reasons.

Interpretation conclusion: VL is emerging in Himalayan (Uttarakhand) region and has been found to have higher mortality and organ involvement (hepatomegaly) compared to non-Himalayan region. This calls for initiating a surveillance program before declaring elimination/eradication.

Background objectives: In 2010, artesunate and sulfadoxine-pyrimethamine (AS+SP) were adopted as the first-line artemisinin based combination therapy for treatment of uncomplicated Plasmodium falciparum malaria in India. Continuous therapeutic efficacy monitoring of first line anti-malarial drugs is required to update the treatment policy for malaria control and elimination. This study aimed to assess the therapeutic efficacy of artesunate and sulfadoxine-pyrimethamine (AS+SP) at three sites with different diseases transmission intensity.

Methods: A 28-day, single-arm, prospective study was conducted to evaluate the clinical and parasitological response to AS+SP. Patients received a six-dose regimen of AS+SP over three days and were monitored for 28 days through clinical and laboratory assessments. Participant recruitment and outcome classification was done as per WHO guidelines for surveillance of anti-malarial drug efficacy.

Results: A total of 170 participants were enrolled and 147 of them completed the follow-up. Adequate clinical and parasitological response (ACPR) was observed in 100% of the study participants who completed the follow-up. 100% fever clearance as well as parasite clearance was observed on day 3.

Interpretation conclusion: This study demonstrated high therapeutic efficacy and a good safety profile for artesunate and sulfadoxine-pyrimethamine at different transmission intensities. This suggests the continuation of the current artemisinin-based combination therapy for the treatment of P. falciparum malaria in India.

Background objectives: With an annual prevalence of 2000 cases, India has the highest global burden of Japanese encephalitis (JE). However, the distribution of the disease is not uniform across the country, wherein the states and districts considered endemic are prioritized for vaccination and other control measures. The central Indian state of Madhya Pradesh (MP), which is not yet considered JE-endemic, possesses multiple agents, hosts, and environmental risk factors and is geographically close to several hotspots of transmission. In this study, we explored the potential endemicity of JE in MP by estimating its prevalence in acute encephalitis syndrome (AES) cases, examining its geospatial and temporal distribution, and demonstrating evidence of viremia in known animal reservoirs.

Methods: A total of 761 human samples were analyzed using an ELISA kit to detect anti-JEV IgM antibodies. Nested and hemi-nested RT-PCR targeting the C-prM region were employed for 93 ELISA-positive human samples, as well as 100 swine and 99 equine samples.

Results: We observed a prevalence of 13% (99 out of 761) of JE in AES cases, predominantly affecting the pediatric population (73.74%) without any gender predisposition. We found JE viremia in 7% of swine and 8% of equine samples as potential animal reservoirs.

Interpretation conclusion: The study revealed a geospatial distribution of the virus in reservoirs and/or hosts across 22 districts, with high- and intermediate-burden districts clustering near the state's border with other JE-endemic states. The temporal distribution indicated that the virus circulated throughout the year.

Background objectives: The present study aimed to assess the impact of various blood or food sources on specific biological parameters of Phlebotomus sergenti Parrot, 1917, adult and immature stages, as well as the development of Leishmania tropica Wright 1903.

Methods: Sandflies were collected from a rural district and subsequently reared in an insectary using standard methods. Three larval diets were formulated and administered to the larvae. Adult sandflies were provided with three blood sources: BALB/c mice, humans, and poultry. The infection of sandflies with the parasite was examined to determine the development of Leishmania .

Results: The duration of larval and pupal stage development exhibited significant differences among the three food sources. However, these variations did not significantly affect the overall length of the immature period of Ph. sergenti (P= 0.098) or the mortality rate (P= 0.338) across the groups. The time required for oviposition differed significantly depending on the blood source (P= 0.007). Nevertheless, the fecundity and longevity of sandflies that fed on the three different blood sources did not show statistically significant differences (fecundity (P= 0.106)/longevity (P= 0.209)). Furthermore, no significant disparity was observed among the three types of blood sources concerning their ability to support L. tropica infection within Ph. sergenti's gut.

Interpretation conclusion: Redirecting the vector, Ph. sergenti , towards these specific food or blood sources as a means to reduce vector population or their vectorial capacity would not be a successful approach for interrupting the transmission cycle.

Background objectives: The breeding potential of vector mosquitoes of dengue and chikungunya viruses in and around airport and seaport of Sri Vijaya Puram (Port Blair), Andaman & Nicobar Islands was explored.

Methods: The survey was carried out for two years during the months of March and April. All the water holding containers in the residential and non-residential areas of the airport and seaport were surveyed for Aedes immatures.

Results: The Stegomyia indices were higher in 2023 compared to 2024. The indices in 2023; the HI, CI, BI and PI were 20.1, 5.6, 32.4 and 86.0, respectively, whereas in 2024, these values declined to 6.8, 1.9, 9.6 and 17.4. Two Aedes species; Ae. aegypti and Ae. albopictus were found in the surveyed containers, with the former in higher proportion. In 2023, larger drum/tanks had higher CI values, while in 2024 smaller containers had more positivity. Ovitrap index showed significant difference (P<0.05) between the two years in both airport and seaport. The percentage positivity for Aedes eggs was 41.2% (n=97) and 36.7% (n=79) in airport and seaport respectively.

Interpretation conclusion: This study is the first comprehensive entomological survey conducted at the Sri Vijaya Puram International Airport and seaport. It offers data on Aedes mosquitoes, especially Ae. aegypti , principal vector of arboviruses, at critical entry points, which are the key vulnerable zones of Andaman & Nicobar archipelago. This study highlights the urgent need for systematic vector surveillance and effective control measures.

Background objectives: Cutaneous leishmaniasis (CL) is a neglected tropical disease that can lead to chronic ulcerative wounds. The low efficacy and high cytotoxicity of current treatments for leishmaniasis is an important health issue. This study assessed the anti-leishmanial effects of stem bark extract of Rhamnus cathartica and nano-emodin (NE) against Leishmania major (L. major) in vitro and in vivo .

Methods: Emodin was prepared chemically and physically, and was formulated into nanoliposomes at concentrations of 25-400 μg/ml. The activity of nanoliposomes were evaluated in vitro and in vivo on cutaneous leishmaniasis in BALB/c mice. Results were analyzed using Prism and SPSS software. Statistical significance was determined using t-test and ANOVA.

Results: The results showed that the anti-parasitic effect of nano-emodin increased time and dose-dependently both in vivo and in vitro . 400 μg/ml of NE showed the highest inhibitory effects on L. major promastigotes. Also, this concentration could reduce the number of L. major amastigotes. Furthermore, the results of histopathological investigation indicated that all concentrations of nano-emodin had no nephrotoxicity and hepatotoxicity.

Interpretation conclusion: Considering the excellent anti-leishmanial effect of emodin nanoliposomes in addition to the non-toxicity, it can be concluded that this natural compound can be a suitable candidate for the treatment of cutaneous leishmaniasis.

Background objectives: Dengue fever is the most common arboviral disease and a serious public health problem, transmitted by Aedes mosquito. Entomological investigations were carried out in dengue affected villages and urban areas of Haridwar district, Uttarakhand, India to investigate the prevalence, distribution of Aedes mosquitoes and identify high risk areas in Haridwar for proposing control.

Methods: The entomological survey was carried out in all selected localities in different breeding habitats like domestic and peridomestic containers to detect Ae. aegypti breeding with the help of standard entomological techniques. About 777 houses were screened from 12 dengue affected villages and municipal areas of Haridwar district during the month of November 2021.

Results: Out of 777 surveyed houses, 119 (15.3%) houses have Aedes breeding while out of 4360 water containers only 158 (3.6 %) were found positive for Aedes breeding. During survey HI (15.32), CI (3.62), BI (20.33) and PI (35.78) were also calculated. The distribution of Aedes larvae and Breeding Preference Ratio in different type of breeding habitats were also estimated, the highest positivity of Ae. aegypti larvae was observed in underground/ ground level cemented tanks (7.94) followed by tray of domestic refrigerator (4.55), discarded tyres (3.72), desert coolers (1.70), plastic containers (1.47), junk materials (1.28), mud-pots (0.58) and flowerpots (0.42), respectively.

Interpretation conclusion: Aedes aegypti mosquito was found to be the dominant species in domestic and peri-domestic breeding habitats, while Aedes albopictus and Aedes vittatus mosquito were also observed in outdoor breeding habitats of the houses. Breeding of Aedes mosquito was found in water storage containers from the same areas where dengue cases were also reported.

Background objectives: Plasmodium falciparum is a protozoan parasite that causes malaria in humans. It is considered as the deadliest species of Plasmodium that infects humans. Research continues to focus on understanding the biology and genetics of P. falciparum to develop new tools, vaccines, and treatments aimed at reducing the global burden of malaria caused by this parasite.

Methods: In this study, three active compounds chrysin, indole-3-carbinol, and curcumin, were optimized using Gaussian16, and a molecular docking study was conducted against Plasmodium falciparum 3D7, along with an evaluation of pharmacokinetic properties.

Results: Molecular docking studies indicated that the chrysin compound exhibits a stronger binding affinity to selected receptors of P. falciparum compared to the other compounds. Additionally, in silico ADME screening was used to predict the pharmacological characteristics of potential drugs and their metabolites.

Interpretation conclusion: The findings predict that the chrysin compound exhibits better affinity with P. falciparum proteins, suggesting that this compound can effectively interact with specific targets within the parasite. It also highlights the favorable electrostatic interactions that contribute to its pharmacological effectiveness as an acetyl-CoA reductase inhibitor.