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An endemic focus of cutaneous leishmaniasis (CL) is located in the Sutlej River Valley in Himachal Pradesh (India) in the north-western Himalaya where CL co-exists with visceral leishmaniasis (VL). In areas of the Indian subcontinent such as Rajasthan, cutaneous leishmaniasis is transmitted by Phlebotomus papatasi (Scopoli) and Phlebotomus salehi. In Himachal Pradesh, Phlebotomus longiductus (Parrot) is suspected to be the vector for CL. In the current study, sand flies were collected and tested for Leishmania infection and to confirm the vector species causing CL. Sand flies were collected during April and September of 2017–2019 from CL endemic villages of Rampur (Shimla), Nirmand (Kullu) and Nichar (Kinnaur) districts of Himachal Pradesh. The sand flies were identified as Phlebotomus (adlerius) longiductus (Parrot) and Phlebotomus (larrousisus) major (Annandale). The density of P. longiductus was found highest. The elevation of villages ranged from 947 m to 2,130 m and were far from the presence of subsoil water. Field collected sand flies tested positive (7.69%) for Leishmania donovani by PCR-RFLP. The L. donovani sequences detected from P. longiductus were 97% similar to L. donovani sequences reported from the cases of CL in Himachal Pradesh.The Leishmania positive sand flies were morphologically identified as Phlebotomus adlerious longiductus providing one step further evidence towards the vector status of CL in Himachal Pradesh. The findings of the study are of epidemiological significance for strategic planning of vector control for leishmaniasis in India.

Vector-borne diseases (VBD) constitute 17% of all infectious diseases that pose a major public health concern around the world. In India, VBD like malaria and dengue continue to account for a significant disease burden. Management of these diseases is dependent in part upon effective vector control and hence several vector control strategies are in use for controlling mosquito populations. However, vectors evolve over time and become capable of averting many of the used control measures, leading to a constant need to find for novel and improved interventions. Attractive toxic sugar bait (ATSB) is a novel vector control strategy that is highly effective at regulating vector density in a particular area. ATSBs exploit the sugar feeding behaviour of mosquitoes. They are developed by combining small amounts of toxins with sugar. A chemical attractant is also included to lure the mosquito into the toxic sugary trap. Although effective, ATSB testing has been limited in scope around the world and ATSBs are completely unexplored in India. In this review, we provide an in-depth account of the development of ATSBs. We highlight the potential of ATSBs in controlling major Indian vectors of malaria and dengue, and we discuss possible challenges that could affect the efficacy of ATSBs in India. © 2020 Society of Chemical Industry.

An outbreak of Japanese encephalitis (JE) was reported in Solan district of Himachal Pradesh, India in May 2018 wherein a total of eight JE cases were reported by the state health department, of which seven cases were confirmed by ELISA. An entomological survey was carried out to investigate the presence of vector mosquitoes in the affected area. Field visits were undertaken in eight villages of two blocks in Solan district. Larval collections were made from the major aquatic sites and emerging mosquito species were identified. Seepage water ditches were the main source of JE vector mosquitoes Culex tritaeniorhynchus and Cx. bitaeniorhynchus. During hand catch collections of adult mosquitoes, three vector species of JE,Culex tritaeniorhynchus (Man Hour Density 1–14), Cx. vishnui (MHD 2) and Cx. bitaeniorhynchus (MHD 1–2) were collected. A few specimens of Cx. tritaeniorhynchus (6 no.) were also collected in light trap collections. Since this was the first reported outbreak of JE from Himachal Pradesh, India, studies on sero-surveillance in addition to bionomics of JE vectors are required for better understanding of epidemiology of JE in Himachal Pradesh. Moreover, there is a need to study the role of climate change especially rising temperature in the context of JE in Himachal Pradesh.

Background Dengue is rapidly expanding climate-sensitive mosquito-borne disease worldwide. Outbreaks of dengue occur in various parts of India as well but there is no tool to provide early warning. The current study was, therefore, undertaken to find out the link between El Niño, precipitation, and dengue cases, which could help in early preparedness for control of dengue. Methods Data on Oceanic Niño Index (ONI) was extracted from CPC-IRI (USA) while the data on monthly rainfall was procured from India Meteorological Department. Data on annual dengue cases was taken from the website of National Vector Borne Disease Control Programme (NVBDCP). Correlation analysis was used to analyse the relationship between seasonal positive ONI, rainfall index and dengue case index based on past 20 years’ state-level data. The dengue case index representing ‘relative deviation from mean’ was correlated to the 3 months average ONI. The computed r values of dengue case index and positive ONI were further interpreted using generated spatial correlation map. The short-term prediction of dengue probability map has been prepared based on phase-wise (El Niño, La Niña, and Neutral) 20 years averaged ONI. Results A high correlation between positive ONI and dengue incidence was found, particularly in the states of Arunachal Pradesh, Chhattisgarh, Haryana, Uttarakhand, Andaman and Nicobar Islands, Delhi, Daman and Diu. The states like Assam, Himachal Pradesh, Meghalaya, Manipur, Mizoram, Jammu & Kashmir, Uttar Pradesh, Orissa, and Andhra Pradesh shown negative correlation between summer El Niño and dengue incidence. Two - three month lag was found between monthly ‘rainfall index’ and dengue cases at local-scale analysis. Conclusion The generated map signifies the spatial correlation between positive ONI and dengue case index, indicating positive correlation in the central part, while negative correlation in some coastal, northern, and north-eastern part of India. The findings offer a tool for early preparedness for undertaking intervention measures against dengue by the national programme at state level. For further improvement of results, study at micro-scale district level for finding month-wise association with Indian Ocean Dipole and local weather variables is desired for better explanation of dengue outbreaks in the states with ‘no association’.

Background & objectives: Climate change is an emerging issue particularly in the context of vector-borne diseases. A study was undertaken in Nainital and Almora districts of Uttarakhand to provide evidences of changing climatic conditions, abundance of vectors, and knocking of malaria in hilly areas. Material and methods: Longitudinal data on temperature and relative humidity were procured from Tussar Silk Centre, Bhimtal, India as well as generated using HOBO device. Monthly density of malaria vectors, their positivity for sporozoite proteins of malaria parasite and fever surveys were conducted as per the standard procedures from 2010 to 2013. Epidemiological data were procured from the State Programme Officer of Uttarakhand state. Results: It was found that the temperature has increased since 1990 resulting in extension in windows of malaria transmission, temporal distribution as well as man hour density of Anopheles culicifacies and An. fluviatilis in hilly districts of Uttarakhand state. Both the vectors were found in high density up to a maximum man hour density of 110 (An. culicifacies) and 69 (An. fluviatilis) as compared to 32 and 33, respectively during 1998. The field collected vector species were also found positive for sporozoite proteins of malaria parasites in the month of October and November. Evidence of occurrence of malaria cases was also found in areas hitherto free from malaria. Interpretation & conclusion: The findings reveal that Himalayan region needs attention to strengthen surveillance for malaria to identify emerging new foci of malaria transmission in view of climate change. Health education to communities about preventive measures to contain breeding of vectors and seeking timely treatment should be imparted so as to achieve the goal of malaria elimination in category-1 in the first instance.

The present study was planned to characterize the microclimate experienced by Aedes larvae in different breeding habitats by determining the temperature variations in water kept in containers during different months under natural conditions. The study was conducted in three municipal zones of Delhi. In each site, four types of container material (plastic, cement, iron and ceramic) were chosen for recording the water temperature in the containers. Daily air and water temperatures (mean, maximum and minimum values) recorded by HOBO and Tidbit data loggers, respectively, were compared using analysis of variance and Tukey’s honest significant difference (HSD) tests. Mean monthly temperature of water varied from 16.9 to 33.0 °C in tin containers, 17.3 to 35.6°C in plastic containers, 14.3 to 28.5°C in ceramic pots, 23.3 to 30.4°C in cemented underground tanks (UGT) and 15.8 to 35.1°C in cemented overhead tanks (OHTs). Corresponding values for the air temperature ranged from 17.7 to 36.1°C. The difference between temperature of water in the containers and air temperature was highest for ceramic pots. Daily mean, maximum and minimum temperatures recorded by different data loggers differed significantly (P

Four xanthones were isolated from the roots of Andrographis paniculata using a combination of column and thin-layer chromatographic methods. They were characterized as (i) 1,8-di-hydroxy-3,7-dimethoxy-xanthone, (ii) 4,8-dihydroxy-2,7-dimethoxy-xanthone, (iii) 1,2-dihydroxy-6,8-dimethoxy-xanthone and (iv) 3,7,8-trimethoxy-1-hydroxy xanthone by IR, MS and NMR spectroscopic methods. In vitro study revealed that compound 1,2-dihydroxy-6,8-dimethoxy-xanthone possessed substantial anti-plasmodial activity against Plasmodium falciparum with its IC(50) value of 4 microg ml(-1). Xanthones bearing hydroxyl group at 2 position demonstrated most potent activity while xanthones with hydroxyl group at 1,4 or 8 position possessed very low activity. In vivo anti-malarial sensitivity test of this compound on Swiss Albino mice with Plasmodium berghei infection using Peters' 4-day test gave substantial reduction (62%) in parasitaemia after treating the mice with 30 mg kg(-1) dose. In vitro cytotoxicity against mammalian cells revealed that 1,2-dihydroxy-6,8-dimethoxy-xanthone is non-cytotoxic with its IC(50) > 32 microg ml(-1).

Nainital District is situated at an altitude of 1934 m (MSL) at southern extremity of lesser Himalyan zone in Kumaun region of U.P state, India. It is located at 29.23 north latitude and 79.3 east longitude having an area of 6794 km. The terrain is heterogenous consisting of 18% hilly forest, 47% forest, 4% bhabar and 29% terai area with a net work of lakes, rivers, rivulets and canals. The average rainfall ranged from 1275 mm to 3050 mm depending on the terrain. Five lakes namely Bhimtal, Sattal, Khurpatal, Naukuchiatal and Nainital are situated in the hilly area of Nainital region. It may be noted that no insecticide was used in the vicinity of lakes for vector control programme while DDT and HCH were extensively used in Terai and Bhabar area for malaria control. Water from these lakes was the only source for drinking and domestic use for people residing in these areas. Lakes water was supplied to the community through water pipe after some treatment. Therefore the present study was conducted to monitor the levels of HCH and DDT in the water from these five lakes of Nainital.

Background & objectives: A retrospective study on chikungunya outbreak in India in five States viz. Delhi, Madhya Pradesh, Orissa, Maharashtra and Kerala was conducted in 2007-2008 to know the distribution and determinants of chikungunya fever outbreak in India. Methods: On the basis of high and low incidence of chikungunya fever, two districts from each State and two wards from the selected district were taken for random selection of 1000 households from 10 districts and 5 States. Semi-structured questionnaires were administered to individuals, patients, qualified health professionals and to stakeholders for collecting information. Results: The educational background and occupation of the respondents showed variations across the study States. Only in high incidence ward of Maharashtra, water storage period for 3-6 days and emptying, drying of water containers on weekly basis was noted. The study through knowledge, attitude, belief, practice (KABP) obtained individual's perception of chikungunya fever, its prevention and control. Patients’ expenditure on treatment was mainly recorded less than Rs 500 across study States. Health facility survey obtained an overview of the capacity of local health facilities. Stakeholders’ perception regarding chikungunya fever was also noted. Interpretation & Conclusions: The study revealed differences in awareness of chikungunya, cause of the disease, vector responsible, mode of transmission, biting time and elimination of breeding of mosquitoes statistically significant among high and low incidence wards of all the States. Expenditure on treatment was independent of economically active status and loss of man-days across all the States. Education and occupation did not have any relation with emptying/drying of water containers in high incidence wards. Strengthening of surveillance, information, education and communication (IEC) activities along with case management facilities may be provided by the State health department for prevention of chikungunya outbreaks in future. Stakeholders should be more involved in outbreak management and future planning.

Breeding behaviour and seasonal prevalence of vector anopheline in different habitats associated with rice land agroecosystem of terai and bhabar area of District Naini Tal was studied from July 1992 to June 1994. Adult prevalence in both the areas shows two distinct An. fluviatilis peaks in the months of March and October and the breeding places for the species were pokhars in bhabar and stream and irrigation drains in terai. Prevalence of adult An. culicifacies was observed during July to August in bhabar and April and August in terai. In bhabar high immature density of An. culicifacies was noted mainly in tanks, pokhars and paddy fields (early transplantation period). In terai high immature density of An. culicifacies was noted in stream, while low in paddy fields. Higher prevalence of immatures and adult anopheline vectors coincide with peak malaria incidence in both the areas. In bhabar in the months of August and September large number of malaria cases were contributed by An. culicifacies and in November by An. fluviatilis. In terai, malaria cases in April and from June to September were contributed by An. culicifacies, whereas An. fluviatilis might be responsible for transmission in October.

Background Synthetic pyrethroids are potent insecticides most commonly used in the vector control programme. These are applied for indoor residual sprays, space sprays and in impregnated bed nets. Resistance reduces the efficacy of insecticides. Thus, the susceptibility status of the target vector(s) is monitored routinely to select the effective ones. A study was undertaken in a malaria endemic coastal city Mangalore, Karnataka, South India, against the known malaria vector Anopheles stephensi. Methods The susceptibility status was assessed at diagnostic doses of DDT (4%), malathion (5%), deltamethrin (0.05%), cyfluthrin (0.15%), alphacypermethrin (0.10%), lambdacyhalothrin (0.05%) and permethrin (0.75%) using the standard WHO tube test method during October/November 2006. Results Anopheles stephensi was resistant to malathion by 54.9%, but tolerant to deltamethrin by 86.1%, cyfluthrin 95.5% and alphacypermethrin 90.6%, whereas it was susceptible to DDT by 98.1%, lambdacyhalothrin 98.6% and permethrin 100.0%, respectively. The KDT50 and KDT95 values for these insecticides also showed the similar responses. Conclusion Susceptibility of An. stephensi to DDT is an important finding as this has never been used in Mangalore city, whereas its rural counterpart Anopheles culicifacies is widely resistant to this insecticide. The study explores the selection and rotation of the appropriate insecticide molecule even within the same group for effective vector management.

"In this paper an attempt is made to describe the probability model of the total number of migrants [at the household level]. The suitability of the model is tested through observed data [for India]."