Molecular characterization of anopheline species diversity in the Andaman and Nicobar archipelago, with a particular emphasis on Anopheles barbirostris.

This study investigates anopheline species diversity in the Andaman and Nicobar Islands, employing morphological and molecular methods, focusing on the D3 domain of 28S rRNA (D3) and second internal spacer (ITS2). Ten Anopheline species were identified morphologically and confirmed with molecular markers. While the D3 region demonstrated low level of inter- and intra-specific genetic distance in all the species, ITS2 revealed clear barcoding gap.

Biodiversity of mosquitoes (Diptera: Culicidae) in phytotelmata from Car Nicobar Island, India.

The Culicidae mosquito family breeds in various natural and artificial water bodies. Phytotelmata are plant structures that hold water and are used by many mosquito species during their life cycle. Mosquitoes are disease vectors, and phytotelmata play an important role in harbouring them.

Genetic differentiation among Aedes aegypti populations from different eco-geographical zones of India.

The present study explicitly evaluated the genetic structure of Aedes aegypti Linn, the vector of dengue, chikungunya, and Zika viruses, across different geo-climatic zones of India and also elucidated the impact of ecological and topographic factors. After data quality checks and removal of samples with excess null alleles, the final analysis was performed on 589 individual samples using 10 microsatellite markers. Overall findings of this study suggested that, Ae.

Characterization of the anopheline vector breeding habitats: Implications for elimination of malaria in tribal inhabited Car Nicobar Island.

Background & Objectives: Malaria is an important public health problem in Andaman & Nicobar archipelago. Among the three districts, Nicobar is the most endemic district where API is >2. In this district, the malaria incidence in Car Nicobar Tehsil has declined steadily over the past 10 years.

Nation-wide vector surveillance on Zika and Dengue did not indicate transmission of the American lineage-pandemic Zika virus in India.

Objectives: Following the Public Health Emergency of International Concern declared on Zika by the World Health Organization during 2016, the Indian Council of Medical Research carried out nationwide vector surveillance for Zika and Dengue viruses (ZIKV and DENV) in India as a preparedness measure in 2016-19.

Methods: High-risk zones distributed to 49 Districts in 14 states/union territories were included in the study. Seven ICMR institutions participated, following a standard operating protocol.

Anopheles sundaicus Mosquitoes as Vector for Plasmodium knowlesi, Andaman and Nicobar Islands, India.

Using PCR and sequencing, we found Plasmodium knowlesi in the malaria vector Anopheles sundaicus mosquito collected from Katchal Island in the Andaman and Nicobar Islands, India. We cannot rule out natural transmission of this parasite to humans through this mosquito species. An in-depth investigation is needed to prevent disease outbreaks.

Correlation Between Physicochemical Properties of Soil and Presence of Leptospira.

Leptospirosis is an important global public health problem. Favourable environmental factors are influencing the survival of leptospires in soil, which is an important link in the transmission cycle. The present study was designed to understand the correlation between various soil nutrients and presence of Leptospira in soil samples of different regions of Andaman and Nicobar Islands.

Changing trend in the seroprevalence and risk factors of human leptospirosis in the South Andaman Island, India.

Seroprevalence of leptospirosis among a healthy population of the South Andaman Island was assessed through random sampling. Previous studies have high seroprevalences of up to 55% in general population and 65% in agricultural labourers. The study subjects (1,181 in total, 781 rural and 400 urban) were interviewed and tested for antibodies against Leptospira.

Can Subminimal Inhibitory Concentrations of Antibiotics Induce the Formation of Biofilm in Leptospira?

Antibiotics at subminimal inhibitory concentrations (sub-MICs) are known to induce biofilm formation in numerous bacteria in vitro. In this report, the effect of sub-MIC levels of antibiotics (doxycycline and tetracycline) on biofilm formation by leptospiral reference strains and isolates was investigated. The sub-MIC levels of both tetracycline and doxycycline were able to induce biofilm in some of the leptospiral strains.

Antimicrobial and antimalarial properties of medicinal plants used by the indigenous tribes of Andaman and Nicobar Islands, India.

In this study, methanol extracts of six medicinal plants (Alstonia macrophylla, Claoxylon indicum, Dillenia andamanica, Jasminum syringifolium, Miliusia andamanica and Pedilanthus tithymaloides) traditionally used by Nicobarese tribes of Andaman and Nicobar Islands were studied for antimicrobial and antimalarial activities as well as preliminary photochemical analysis. Plants were collected from Car Nicobar of Andaman and Nicobar Islands and the ethnobotanical data were gathered from traditional healers who inhabit the study area. The methanol extracts were obtained by cold percolation method and the antimicrobial activity was found using agar well diffusion method.

In Vitro Antimicrobial Susceptibility of Pathogenic Leptospira Biofilm.

Pathogenic Leptospira spp. are the causative agent of leptospirosis. Biofilm formation in leptospires is a new area of study, and its role in pathogenesis is not fully explored.

Can community-based integrated vector control hasten the process of LF elimination?

Community-based integrated vector control (IVC) using polystyrene beads (EPS) and pyrethroid impregnated curtains (PIC) as an adjunct to mass drug administration (MDA) was implemented for lymphatic filariasis elimination, in the filaria endemic villages of Tirukoilur, south India. In all the villages, MDA was carried out by the state health machinery, as part of the national filariasis elimination programme. Thirty-six difficult-to-control villages were grouped as, viz, MDA alone, MDA + EPS and MDA + EPS + PIC arms.

Studies on insecticide susceptibility of Aedes aegypti (Linn) and Aedes albopictus (Skuse) vectors of dengue and chikungunya in Andaman and Nicobar Islands, India.

Dengue and chikungunya are important arboviral infections in the Andaman Islands. Competent vectors viz. Aedes aegypti and Aedes albopictus are widely prevalent.

Host-feeding pattern of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in heterogeneous landscapes of South Andaman, Andaman and Nicobar Islands, India.

Mosquito foraging behavior is a determinant of host-vector contact and has an impact on the risk of arboviral epidemics. Therefore, blood-feeding patterns is a useful tool for assessing the role in pathogen transmission by vector mosquitoes. Competent vectors of dengue and chikungunya viz.

Impact on prevalence of intestinal helminth infection in school children administered with seven annual rounds of diethyl carbamazine (DEC) with albendazole.

Background & Objectives: One third of the world's population is infected with one or more of the most common soil-transmitted helminths (STH). Albendazole (ALB) is being administered with diethyl carbamazine (DEC) in filariasis endemic areas to eliminate lymphatic filariasis (LF) and helminth infections. In this study, the cumulative impact of seven annual rounds of mass drug administrations (MDA) of DEC and ALB on STH infection in school children in selected villages in southern India was determined.

Decline in lymphatic filariasis transmission with annual mass drug administration using DEC with and without albendazole over a 10year period in India.

The National Programme for the Elimination of Lymphatic Filariasis is underway in the endemic districts of Tamil Nadu State, South India, since 2001. Annual mass drug administration (MDA) was carried out by the state health department to all eligible individuals. The impact of MDAs on transmission parameters was evaluated in 2 revenue blocks, viz, one with DEC alone and the other with a combination of albendazole.

Persistence of lymphatic filarial infection in the paediatric population of rural community, after six rounds of annual mass drug administrations.

Under the Global Programme to Eliminate Lymphatic Filariasis (LF), mass drug administration (MDA) is being implemented in Tamil Nadu, south India, by the State health machinery. The impact of six annual rounds of MDA using diethylcarbamazine (DEC) with and without albendazole (ALB) on filarial infection (microfilaraemia prevalence-MFP; antigenaemia prevalence-AGP) in paediatric population of 2-9 years was determined in two revenue blocks, with a population of 321 000. After each MDA, 300-400 children were screened for filarial infection.

Lymphatic filariasis elimination programme in Andaman and Nicobar Islands, India: drug coverage and compliance post eight rounds of MDA.

Lymphatic filariasis (LF) is endemic in the Andaman and Nicobar islands, including the lone foci for a diurnally sub-periodic form of Wuchereria bancrofti in the Nancowry group of islands. A programme to eliminate LF was launched in 2004 by the Directorate of Health Services, Andaman and Nicobar Administration which involved a single annual mass drug administration (MDA) using diethylcarbamazine (DEC) with albendazole. So far, eight rounds of MDA have been implemented through the Public Health Care network.

Detection of Wolbachia endobacteria in Culex quinquefasciatus by Gimenez staining and confirmation by PCR.

Background & Objectives: Wolbachia are common intracellular bacteria that are found in arthropods and nematodes. These endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, including the induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-egg incompatibility. Since they can also move horizontally across species boundaries, Wolbachia is gaining importance in recent days as it could be used as a biological control agent to control vector mosquitoes or for paratransgenic approaches.

Wolbachia endobacteria in a natural population of Culex quinquefasciatus from filariasis endemic villages of south India and its phylogenetic implication.

Understanding Wolbachia mosquito interactions have been recognized as an important concept to develop novel vector control strategies. The prevalence of Wolbachia endobacteria in a natural population of the filariasis vector Culex quinquefasciatus was determined by the polymerase chain reaction method. Earlier workers had estimated the infection rates of Wolbachia with only one or very few individuals per species.

Role of community empowerment in the elimination of lymphatic filariasis in south India.

The World Health Assembly in 1997 has targeted the elimination of lymphatic filariasis (LF) by 2020, and in India the goal has been set for the year 2015 by annual single dose mass drug administration (MDA). The role of community empowerment in enhancing the drug compliance and bringing out the function of various methods used to disseminate the information on MDA to the villagers is focused. A longitudinal survey was carried out in nine villages in Tirukoilur block of Villupuram district, Tamil Nadu for filarial infection variables like microfilaraemia, antigenaemia, transmission indices before and after each MDA, to determine the drug impact.

Impact of ivermectin drug combinations on Pediculus humanus capitis infestation in primary schoolchildren of south Indian rural villages.

Background: Antifilarial drug combinations including ivermectin provide antifilarial activity with ancillary benefits on intestinal helminths and ectoparasites, such as chiggers and lice. The impact of single oral dose of antifilarial drugs, viz; (1) diethylcarbamazine (DEC) alone, (ii) DEC + albendazole (ALB), (iii) ivermectin (IVR) + DEC and (iv) IVR + ALB, was determined, on the head louse (Pediculus humanus capitis) in primary school children in a rural community in south India.

Methods: Primary school children (n = 534) of age 6-10 years from four villages of South India were examined for the presence of head lice before and after single dose of DEC + ivermectin drug combination.