Anti-SARS-CoV-2 antibody kinetics up to 6 months of follow-up: Result from a nation-wide population-based, age stratified sero-epidemiological prospective cohort study in India

Repeated serological testing tells about the change in the overall infection in a community. This study aimed to evaluate changes in antibody prevalence and kinetics in a closed cohort over six months in different sub-populations in India. The study included 10,000 participants from rural and urban areas in five states and measured SARS-CoV-2 antibodies in serum in three follow-up rounds. The overall seroprevalence increased from 73.9% in round one to 90.7% in round two and 92.9% in round three. Among seropositive rural participants in round one, 98.2% remained positive in round two, and this percentage remained stable in urban and tribal areas in round three. The results showed high antibody prevalence that increased over time and was not different based on area, age group, or sex. Vaccinated individuals had higher antibody prevalence, and nearly all participants had antibody positivity for up to six months.

First Report of Rubber Collection Bowls & Plastic and Bamboo Water Containers as the Major Breeding Source of Ae. albopictus with the Indigenous Transmission of Dengue and Chikungunya in Rural Forested Malaria-Endemic Villages of Dhalai District, Tripura, India: The Importance of Molecular Identification

BACKGROUND

With the reports of indigenous cases of dengue and chikungunya in the forest-covered rural tribal malaria-endemic villages of Dhalai District, Tripura, India, an exploratory study was undertaken to identify the vector breeding sites.

METHODS

From June 2021 to August 2022, mosquito larvae were collected from both natural and artificial sources in the villages, house premises, and their nearby forested areas outside of the houses. Other than morphological characterisation, Aedes species were confirmed by polymerase chain reaction targeting both nuclear (ITS2) and mitochondrial genes (COI) followed by bidirectional Sanger sequencing.

RESULTS

Aedes albopictus was abundantly found in this area in both natural and artificial containers, whereas Ae. aegypti was absent. Among the breeding sources of molecularly confirmed Ae. albopictus species, rubber collection bowls were found to be a breeding source reported for the first time. Plastic and indigenously made bamboo-polythene containers for storing supply water and harvesting rainwater in the villages with a shortage of water were found to be other major breeding sources, which calls for specific vector control strategies. Natural sources like ponds and rainwater collected on Tectona grandis leaves and Colocasia axil were also found to harbour the breeding, along with other commonly found sources like bamboo stumps and tree holes. No artificial containers as a breeding source were found inside the houses. Mixed breeding was observed in many containers with other Aedes and other mosquito species, necessitating molecular identification. We report six haplotypes in this study, among which two are reported for the first time. However, Aedes aegypti was not found in the area. Additionally, rubber collection bowls, ponds, and water containers also showed the presence of Culex quinquefasciatus and Culex vishnui, known JE vectors from this area, and reported JE cases as well. Different Anopheles vector spp. from this known malaria-endemic area were also found, corroborating this area as a hotbed of several vectors and vector-borne diseases.

CONCLUSIONS

This study, for the first time, reports the breeding sources of Aedes albopictus in the forested areas of Tripura, with rubber collection bowls and large water storage containers as major sources. Also, for the first time, this study reports the molecular characterisation of the Ae. albopictus species of Tripura, elucidating the limitations of morphological identification and highlighting the importance of molecular studies for designing appropriate vector control strategies. The study also reports the co-breeding of JE and malaria vectors for the first time in the area reporting these vector-borne diseases.

Current Therapeutic Delivery Approaches Using Nanocarriers for the Treatment of Tuberculosis Disease

Tuberculosis is a major health issue globally and a leading cause of death due to the infective microorganism Mycobacterium tuberculosis. Treatment of drug resistance tuberculosis requires longer treatment with multiple daily doses of drugs. Unfortunately, these drugs are often associated with poor patient compliance. In this situation, a need has been felt for the less toxic, shorter, and more effective treatment of the infected tuberculosis patients. Current research to develop novel anti-tubercular drugs shows hope for better management of the disease. Research on drug targeting and precise delivery of the old anti-tubercular drugs with the help of nanotechnology is promising for effective treatment. This review has discussed the status currently available treatments for tuberculosis patients infected with Mycobacterium alone or in comorbid conditions like diabetes, HIV and cancer. This review also highlighted the challenges in the current treatment and research on the novel anti-tubercular drugs to prevent multi-drug-resistant tuberculosis. It presents the research highlights on the targeted delivery of anti-tubercular drugs using different nanocarriers for preventing multi-drug resistant tuberculosis. Report has shown the importance and development of the research on nanocarriers mediated anti-tubercular delivery of the drugs to overcome the current challenges in tuberculosis treatment.

Sero-prevalence of SARS CoV-2 specific antibody among general population of Tripura, India: A baseline observation

Background: Spectrum of COVID-19 disease ranges from asymptomatic or mild symptomatic to life threatening cases. Population based sero-epidemiological studies are useful for assessing the magnitude of COVID-19 infection in a geographic area and it is helpful for planning control measures. Objectives: To estimate the sero-prevalence of SARS CoV-2 antibody in the general population of Tripura and to study the factors associated with it. Methodology: This community based cross-sectional study was conducted from 15th October to 14th November 2020 among 4800 subjects selected from the whole state of Tripura, India by probability proportionate to size sampling technique using 30 clusters. Electrochemiluminescence (eCLIA) based assay was used to test the serum samples for SARS-CoV-2 specific antibody. Data entry and analysis was performed using SPSS-25 for windows and sero-prevalence was expressed in percentages. Binary logistic regression model was used for predicting sero-positivity by including the significant factors associated with SARS-CoV-2 infection as found out by univariate analysis. Result: Sero-prevalence of SARS-CoV-2 antibody was found to be 34% among the general population of Tripura and it varied from 42.4% to 19.7% across different districts. Logistic regression model has identified, urban residency (OR: 1.21, 95% CI: 1.03-1.42), ethnic community (OR: 0.55, 95% CI: 0.48-0.64) and literacy (OR: 1.41, 95% CI: 1.13-1.77) as the independent risk factors for SARS-CoV-2 sero-positivity (p<0.05). Conclusion: Approximately one out of three residents of Tripura has already acquired the novel SARS CoV-2 infection. As the threshold required for achieving herd immunity against COVID-19 is not yet known, control measures need to be continued for preventing further spread of disease in the community.

Spectral Dependent Photoelectrochemical Behaviors of CdS Sensitized ZnO Nanorods

CdS decorated ZnO nanorods have been grown by a combination of hydrothermal method and successive ion layer absorption and reaction (SILAR) method. Optical absorption and emission properties of ZnO nanorods have been studied after sensitization with CdS nanoparticles. Current-voltage characteristics of ZnO nanorods and CdS sensitized ZnO nanorods have been studied in an electrochemical cell. The spectral dependent photocurrent and photopotential behaviors of ZnO nanorods and CdS sensitized ZnO nanorods have been investigated using monochromatic light of wavelength 300-700 nm. The photopotential recovery time have been estimated for CdS sensitized nanorods and pristine nanorods.