Effect of ultraviolet radiation on immature stages of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes.

Background & objectives: Understanding the influence of ultraviolet light on organisms is important for examining the hazards of exposure to ultraviolet (UV) light. However, little is known about the biological toxicity of ultraviolet light against mosquitoes, which are regularly exposed to UV light. This study was planned to determine the impact of UV radiation on different aquatic stages of Aedes aegypti, Anopheles stephensi and Culex quinquefaciatus mosquitoes. Methods: We exposed I/II instar larvae, III/IV instar larvae and pupae of Ae. aegypti, An. stephensi and Cx. quinquefaciatus mosquitoes to UV radiation of 253 nm wavelength in a closed chamber of 30×30 cm. The exposure was done for different time intervals viz. 1, 2, 3, 4 minutes and so on. Development of larvae/pupae to adult stage was monitored daily and mortality, if any, was recorded. Results: Development of I/II instar larvae of Ae. aegypti and Cx. quinquefasciatus to pupal stage was unsuccessful at an exposure time of one minute while only 1.7% pupation occurred in I/II instar larvae of Ae. aegypti upon similar exposure. When III/IV stage larvae were exposed to UV light, pupal development occurred only at 30seconds and one-minute exposure in An. stephensi and Cx. quinquefaciatus but in Ae. aegypti, no pupation occurred with one-minute exposure. With four-minute UV exposure of pupae, no adult emerged in Ae. aegypti; 33.3% adult emerged in An. stephensi and 66.7% adult emerged in Cx. quinquefaciatus. Interpretation & conclusion: Our results show that UV radiation results in developmental arrest of Ae. aegypti, An. stephensi and Cx. quinquefaciatus mosquitoes.

Insecticide susceptibility status of malaria vectors in Himachal Pradesh, India.

BACKGROUND & OBJECTIVES: The state of Himachal Pradesh is one of the hilly forested states of India. Warming of climate has been evidenced in the state due to the ongoing climate change which may cause the upsurge/introduction of mosquito-borne diseases. To curb disease transmission, an effective vector control strategy will be required. METHODS: Insecticide susceptibility status of available malaria vectors was determined using the standard WHO method in six districts Kangra, Una, Mandi, Bilaspur, Solan and Mandi of the state. An. culicifacies and An. fluviatilis were tested against DDT (4%), malathion (5%) and deltamethrin (0.05%) using WHO insecticide susceptibility kits. RESULTS: Overall, An. culicifacies was found resistant to DDT in all the six districts, susceptible to malathion in all districts except Bilaspur and Solan where it showed possible resistance. It was susceptible to deltamethrin in all the study districts. An. fluviatilis was resistant to DDT and susceptible to malathion and deltamethrin in Kangra and Una districts. INTERPRETATION & CONCLUSION: At present, indoor residual spraying (IRS) is not being undertaken in Himachal Pradesh. However, with the information generated through the present study, the state government can plan evidence-based IRS at least for focal spray in limited foci reporting malaria incidence.

Laboratory evaluation of the efficacy of boric acid containing toxic sugar baits against Anopheles culicifacies, An. stephensi and Aedes aegypti mosquitoes.

BACKGROUND & OBJECTIVES: Attractive toxic sugar baits (ATSB) is a novel tool which employs mosquito sugar feeding behaviour to kill them. The potential of ATSB against mosquito vectors has been demonstrated in limited scope around the world including Israel, some of the African countries and USA. But their efficacy against mosquito vectors of India is yet to be ascertained. Therefore, current study was planned to evaluate the efficacy of TSB (without attractant) against two important malaria vectors Anopheles culicifacies and An. stephensi along with major dengue vector Aedes aegypti. METHODS: TSB solution was prepared by dissolving different concentrations of boric acid in glucose and tested against each of the mosquito species. Another experiment was done by spraying this boric acid sugar solution on to Calendula officinalis plant. It served as a sole source of mosquito feed and mortality of mosquitoes was counted after 24 hours. RESULTS: The TSB resulted in 100% mortality of Ae. aegypti and An. stephensi at 4% concentration of boric acid while in An. culicifacies 100% mortality was achieved at 3% concentration TSB solution. TSB solution with 2% boric acid, resulted in 99.1% mortality in An. culicifacies while ~95 % mortality of An. stephensi and Ae. aegypti. When TSB solution with 2% boric acid was sprayed on plant, ~89-94% mortality was observed in both An. stephensi and An. culicifacies. INTERPRETATION & CONCLUSION: Based on the results, boric acid based toxic sugar bait solution could be a promising tool for vector control. Further studies are needed to find out its toxicity of TSB against non-target organisms and residual efficacy in field trials in different ecotypes.

Validation of micro-chip based PCR assays for diagnosis of both Plasmodium falciparum and Plasmodium vivax.

BACKGROUND & OBJECTIVES: Microscopy is considered as the gold standard for malaria diagnosis, however sub-microscopic infections can only be detected by Polymerase chain reaction, which demands high cost and elaborate laboratory setup. The Micro-chip PCR based Truenat Malaria Pv-Pf and Pf assay is a portable solution for detection of sub-microscopic/asymptomatic cases of malaria in the field, three lots of which were evaluated for P. falciparum and P. vivax malaria. METHODS: Three lots of Truenat® Malaria Pv-Pf and Pf assay (kits) were assessed using blood samples of P. vivax and P. falciparum as well as malaria negative blood samples. DNA was extracted from the blood samples using the Trueprep Auto v2 Universal Cartridge based sample prep device and real time qPCR was performed using Truelab DUO micro PCR Analyzer with three lots of Truenat® Malaria Pv-Pf and Pf Assays. Mean, Standard deviation and one-way analysis of variance (ANOVA) was used to assess the significance of inter-lot variability in Cycle threshold values. RESULTS: The Truenat® Malaria Pv-Pf and Pf assays identified the malaria parasites with 100% accuracy. Based on the test for variance (ANOVA) the inter-lot variability in cycle threshold values were not significant, indicating a high degree of precision. INTERPRETATION & CONCLUSION: Based on high accuracy and precision between different lots, the Truenat® Malaria Pv-Pf and Pf assays were found to be suitable for the diagnosis of sub-microscopic infections in field conditions to provide support in elimination of malaria.

Kyasanur forest disease and climatic attributes in India.

BACKGROUND & OBJECTIVES: In India, Kyasanur Forest Disease has been reported from the states of Karnataka, Kerala, Goa, and Maharashtra. The relationship between climatic factors and transmission of KFD remains untouched, therefore, the present study was undertaken. METHODS: Based on the occurrence of cases, Shivamogga district (Karnataka) and Wayanad district in Kerala and northern Goa (Goa state) were selected for the study. Data on the incidence of KFD and climate factors were collected from concerned authorities. To determine the relationship between dependent and independent variables, spearman's correlation was calculated for monthly as well as with lag months. RESULTS: KFD cases and temperature (°C) were found significantly correlated up to 1 months' lag period (p<0.05) while with precipitation relationship was found negatively significant for 0-3 months' lag. The range of suitable temperature for KFD in Shivamogga, Goa and Wayanad was found as 20-31°C, 25-29°C and 27-31°C respectively. The cumulative precipitation during transmission months (November-May) ranged from <150-500mm, while in non-transmission months (June-October) from >1100-2400mm. INTERPRETATION & CONCLUSION: The analysis of three sites revealed that with the increase in temperature, the intensity of KFD transmission decreases as corroborated by the seasonal fluctuations in Shivamogga, Goa and Wayanad. High precipitation from June to October rovides suitable ecology to tick vector and sets in transmission season from November to May when cumulative precipitation is <500 mm.

Distribution Expansion of Dengue Vectors and Climate Change in India.

India has witnessed a five-fold increase in dengue incidence in the past decade. However, the nation-wide distribution of dengue vectors, and the impacts of climate change are not known. In this study, species distribution modeling was used to predict the baseline and future distribution of Aedine vectors in India on the basis of biologically relevant climatic indicators. Known occurrences of Aedes aegypti and Aedes albopictus were obtained from the Global Biodiversity Information Facility database and previous literature. Bio-climatic variables were used as the potential predictors of vector distribution. After eliminating collinear and low contributing predictors, the baseline and future prevalence of Aedes aegypti and Aedes albopictus was determined, under three Representative Concentration Pathway scenarios (RCP 2.6, RCP 4.5 and RCP 8.5), using the MaxEnt species distribution model. Aedes aegypti was found prevalent in most parts of the southern peninsula, the eastern coastline, north eastern states and the northern plains. In contrast, Aedes albopictus has localized distribution along the eastern and western coastlines, north eastern states and in the lower Himalayas. Under future scenarios of climate change, Aedes aegypti is projected to expand into unsuitable regions of the Thar desert, whereas Aedes albopictus is projected to expand to the upper and trans Himalaya regions of the north. Overall, the results provide a reliable assessment of vectors prevalence in most parts of the country that can be used to guide surveillance efforts, despite minor disagreements with dengue incidence in Rajasthan and the north east, possibly due to behavioral practices and sampling efforts.

Untargeted metabolomics-based response analysis of temperature and insecticide exposure in Aedes aegypti.

In this study, we utilized an untargeted NMR metabolomics approach to identify the vector response in terms of metabolic profiling after temperature and insecticide exposure in comparison with the control. Clearly, temperature and insecticide exposure cause changes in the underlying metabolism, and the NMR metabolomic profile enables a direct examination of the immediate response of the vector to cope up with these changes. The present study was designed in four parts: A-Aedes aegypti were exposed to 40 °C for one-hour, DDT-4%, malathion-5%, and deltamethrin-0.05% separately and, part B-D; one-hour exposure at 35 °C and 40 °C temperatures followed by one-hour exposure to insecticide. The resultant metabolite profiles were compared with the control. In response to temperature and insecticide exposure, several metabolites and altered pathways were identified. Citrate, maltose, lipids, Nicotinate, Choline, Pyruvate and ß-hydroxybutyrate were found as important components of major biological pathways such as tri-carboxylic acid cycle, branched amino acid degradation, glycolysis/gluconeogenesis, amino acid metabolism, lipid and carbohydrate metabolism, nucleotide PRPP pathway, and phospholipid metabolism. Furthermore, the results also suggest that the changes imposed by exposure to temperature and insecticides individually, are reversed with combined exposure, thus negating the impact of each other and posing a threat to the control of Aedes-borne diseases such as dengue, chikungunya, Zika and yellow fever.

Detection of Leishmania donovani in Wild-Caught Phlebotomine Sand Flies in Endemic Focus of Leishmaniasis in Himachal Pradesh, India.

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.

Identification of bio-climatic determinants and potential risk areas for Kyasanur forest disease in Southern India using MaxEnt modelling approach.

BACKGROUND: Kyasanur forest disease (KFD), known as monkey fever, was for the first time reported in 1957 from the Shivamogga district of Karnataka. But since 2011, it has been spreading to the neighbouring state of Kerala, Goa, Maharashtra, and Tamil Nadu. The disease is transmitted to humans, monkeys and by the infected bite of ticks Haemaphysalis spinigera. It is known that deforestation and ecological changes are the main reasons for KFD emergence, but the bio-climatic understanding and emerging pathways remain unknown. METHODS: The present study aims to understand the bio-climatic determinants of distribution of tick vector of KFD in southern India using the Maximum Entropy (MaxEnt) model. The analysis was done using 34 locations of Haemaphysalis spinigera occurrence and nineteen bio-climatic variables from WorldClim. Climatic variables contribution was assessed using the Jackknife test and mean AUC 0.859, indicating the model performs with very high accuracy. RESULTS: Most influential variables affecting the spatial distribution of Haemaphysalis spinigera were the average temperature of the warmest quarter (bio10, contributed 32.5%), average diurnal temperature range (bio2, contributed 21%), precipitation of wettest period (bio13, contributed 17.6%), and annual precipitation (bio12, contributed 11.1%). The highest probability of Haemaphysalis spinigera presence was found when the mean warmest quarter temperature ranged between 25.4 and 30 °C. The risk of availability of the tick increased noticeably when the mean diurnal temperature ranged between 8 and 10 °C. The tick also preferred habitat having an annual mean temperature (bio1) between 23 and 26.2 °C, mean temperature of the driest quarter (bio9) between 20 and 28 °C, and mean temperature of the wettest quarter (bio8) between 22.5 and 25 °C. CONCLUSIONS: The results have established the relationship between bioclimatic variables and KFD tick distribution and mapped the potential areas for KFD in adjacent areas wherein surveillance for the disease is warranted for early preparedness before the occurrence of outbreaks etc. The modelling approach helps link bio-climatic variables with the present and predicted distribution of Haemaphysalis spinigera tick.

Impact of Climate Change on Health and Well-Being of People in Hindu Kush Himalayan Region: A Narrative Review.

Climate change and variability affect virtually everyone and every region of the world but the effects are nowhere more prominent than in mountain regions and people living therein. The Hindu Kush Himalayan (HKH) region is a vast expanse encompassing 18% of the world's mountainous area. Sprawling over 4.3 million km2, the HKH region occupies areas of eight countries namely Nepal, Bhutan, Afghanistan, Bangladesh, China, India, Myanmar, and Pakistan. The HKH region is warming at a rate higher than the global average and precipitation has also increased significantly over the last 6 decades along with increased frequency and intensity of some extreme events. Changes in temperature and precipitation have affected and will like to affect the climate-dependent sectors such as hydrology, agriculture, biodiversity, and human health. This paper aims to document how climate change has impacted and will impact, health and well-being of the people in the HKH region and offers adaptation and mitigation measures to reduce the impacts of climate change on health and well-being of the people. In the HKH region, climate change boosts infectious diseases, non-communicable diseases (NCDs), malnutrition, and injuries. Hence, climate change adaptation and mitigation measures are needed urgently to safeguard vulnerable populations residing in the HKH region.

Typical and atypical cutaneous leishmaniasis in Himachal Pradesh (India).

BACKGROUND: Visceral leishmaniasis (VL) is in elimination phase in India while cutaneous leishmaniasis (CL) is being reported from new foci. In Himachal Pradesh (HP), a foci of CL had been reported along Satluj River, but the causative agent poses a dilemma, hence the present study was undertaken in Shimla, Kullu and Kinnaur districts. METHODS: A total of 28 CL patients from Indira Gandhi Medical College and Hospital Shimla (IGMC) in 2018, were tested by rK39., Twelve fresh cases were subjected to microscopic detection of Leishmania parasite, PCR and sequencing. Skin biopsies of 3-4 mm diameter were cultured, as well as imprints were prepared for the detection of Leishmania amastigotes. Biopsy samples were inoculated into different culture media (M199, RPMI 1640, NNN) and were incubated at 22-24 °C. Polymerase chain reaction (PCR) was performed to characterize Leishmania parasite species. RESULTS: Of 28 patients, one was positive by rK39 dipstick test and one imprint was found positive for Leishmania amstigotes. Twelve biopsy DNA samples subjected to PCR for Leishmania kDNA, were found Lesihmania positive. Identification of Leishmania species was confirmed by PCR-RFLP and sequencing method. Of 12 Leishmania positive samples, six were identified as L. donovani, three L. tropica, two L.major and one remained unidentified. CONCLUSIONS: This study revealed the existence of three species of parasites i.e., L. donovani, L. tropica and L. major indicating the existence of typical and atypical leishmaniasis in Himachal Pradesh. The occurrence of CL cases in HP, Kerala or elsewhere should not be ignored considering them just cases of CL alone. Further studies are warranted to confirm the existence of L.donovani zymodeme MON37 from cases of CL in HP or L.donovani zymodeme MON2 strain causing VL in Bihar. Elimination of CL should also be considered along with goal of Kala -Azar elimination.

El Niño Southern Oscillation as an early warning tool for dengue outbreak in India.

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'.

Larvicidal and antibacterial activity of aqueous leaf extract of Peepal (Ficus religiosa) synthesized nanoparticles.

In this study, the zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) were synthesized using the aqueous leaf extract of Ficus religiosa (Peepal tree). The synthesized nanoparticles were tested as larvicides against the larvae of Anopheles stephensi. Further, the synthesized nanoparticles were tested as antibacterial agents against the Escherichia coli (gram negative) and Staphylococcus aureus (gram positive) bacteria. The synthesized nanoparticles were characterized with UV-visible spectroscopy, X-rays powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The larvicidal mortality was observed after 24 h and 48 h by probit analysis. The antibacterial activity was evaluated using the well diffusion method. The synthesized nanoparticles were irregular shape and varied size. The larvae of An. stephensi were found highly susceptible against the ZnO NPs than the TiO2 NPs and aqueous leaves extract. The highest mortality was observed in synthesized ZnO NPs against first to third instars of (LC50 50, 75, and 5 ppm) and 100% mortality in fourth instars of An. stephensi. The higher zone of inhibition was occurred against the E. coli. This report of present investigation revealed that the rapid biological synthesis of ZnO NPs and TiO2 NPs using aqueous leaf extract of F. religiosa would be effective potential larvicides for mosquito control as well as antimicrobial agents with eco-friendly approach.

Unlicensed medical practitioners in tribal dominated rural areas of central India: bottleneck in malaria elimination.

BACKGROUND: In India, Accredited Social Health Activists (ASHAs) deliver services for diagnosis and treatment of malaria, although unlicensed medical practitioners (UMPs) (informal health providers) are most preferred in communities. A cross sectional survey was conducted to: (i) assess knowledge and treatment-seeking practices in the community, and (ii) explore the diagnosis and treatment practices related to malaria of UMPs working in rural and tribal-dominated high malaria endemic areas of central India, and whether they adhere to the national guidelines. METHODS: A multi-stage sampling method and survey technique was adopted. Heads of the households and UMPs were interviewed using a structured interview schedule to assess knowledge and malaria treatment practices. RESULTS: Knowledge regarding malaria symptoms was generally accurate, but misconceptions emerged related to malaria transmission and mosquito breeding places. Modern preventive measures were poorly accessed by the households. UMPs were the most preferred health providers (49%) and the first choice in households for seeking treatment. UMPs typically lacked knowledge of the names of malaria parasite species and species-specific diagnosis and treatment. Further, irrational use of anti-malarial drugs was common. CONCLUSIONS: UMPs were the most preferred type of health care providers in rural communities where health infrastructure is poor. The study suggests enhancing training of UMPs on national guidelines for malaria diagnosis and treatment to strengthen their ability to contribute to achievement of India's malaria elimination goals.

Entomological investigation of an outbreak of Japanese encephalitis in Solan district, Himachal Pradesh.

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.

Determining the cutoff of rainfall for Plasmodium falciparum malaria outbreaks in India.

BACKGROUND: Malaria outbreaks due to Plasmodium falciparum have been reported from various parts of India. Rainfall is considered as one of the major determinants for malaria outbreaks, however, an estimate of rainfall threshold for malaria is not known. Owing to the vast geographic area, the present study was planned to determine the amount of rainfall required for malaria outbreaks and the lag period between outbreak and rainfall in different Indian climatic regions. METHODS: Simple statistical methods of overall mean and moving mean (case/mean ratio, CMR) were used to identify the districts with P. falciparum malaria outbreak due to rainfall and the amount of rainfall required for outbreaks. Of 120 districts reporting P. falciparum malaria outbreaks, 99 districts having substantially low number of cases (<100); <3 CMR in any year from 2009 to 2012 and districts having stable malaria transmission were excluded. Finally, analysis of outbreak month, lag period and the threshold of rainfall were determined in respect of 21 districts which represent different agro-climatic zones in the country. Whenever the moving mean of cases attained the value ≥3 in any month, that month was identified as P. falciparum malaria outbreak. The threshold amount of rainfall critical for malaria outbreak was calculated by the average mean of previous months (i.e., lag period). RESULTS: The rainfall cutoff ranged from >70 to >600mm in different districts. The month of outbreak varied with the climatic zones viz. arid, semi-arid, humid and per-humid districts. In humid and per-humid districts, outbreaks occurred during monsoon period whereas in arid and semi-arid regions outbreaks occurred during the post monsoon period. The lag period varied from 1-3 months; long lag period was observed in arid, semi-arid region, while short lag period in humid and per-humid regions. CONCLUSION: Malaria outbreaks can occur in post monsoon in arid and semi-arid region whereas in summer/monsoon in humid and per-humid regions. The lag period between rainfall and outbreak differs from one month with short lag (humid and per-humid) to long lag (arid and semi-arid). Based on the determined threshold of rainfall, the findings would be helpful in forewarning of imminent outbreak of malaria for the timely preparedness of malaria outbreaks not only in 21 studied districts, but also in several other districts of different climatic regions of India.

Malaria risk map for India based on climate, ecology and geographical modelling.

Mapping the malaria risk at various geographical levels is often undertaken considering climate suitability, infection rate and/or malaria vector distribution, while the ecological factors related to topography and vegetation cover are generally neglected. The present study abides a holistic approach to risk mapping by including topographic, climatic and vegetation components into the framework of malaria risk modelling. This work attempts to delineate the areas of Plasmodium falciparum and Plasmodium vivax malaria transmission risk in India using seven geo-ecological indicators: temperature, relative humidity, rainfall, forest cover, soil, slope, altitude and the normalized difference vegetation index using multi-criteria decision analysis based on geographical information system (GIS). The weight of the risk indicators was assigned by an analytical hierarchical process with the climate suitability (temperature and humidity) data generated using fuzzy logic. Model validation was done through both primary and secondary datasets. The spatio-ecological model was based on GIS to classify the country into five zones characterized by various levels of malaria transmission risk (very high; high; moderate; low; and very low. The study found that about 13% of the country is under very high malaria risk, which includes the malaria- endemic districts of the states of Chhattisgarh, Odisha, Jharkhand, Tripura, Assam, Meghalaya and Manipur. The study also showed that the transmission risk suitability for P. vivax is higher than that for P. falciparum in the Himalayan region. The field study corroborates the identified malaria risk zones and highlights that the low to moderate risk zones are outbreak-prone. It is expected that this information will help the National Vector Borne Disease Control Programme in India to undertake improved surveillance and conduct target based interventions.

Shift in Potential Malaria Transmission Areas in India, Using the Fuzzy-Based Climate Suitability Malaria Transmission (FCSMT) Model under Changing Climatic Conditions.

The future implications of climate change on malaria transmission at the global level have already been reported, however such evidences are scarce and limited in India. Here our study aims to assess, identify and map the potential effects of climate change on Plasmodium vivax (Pv) and Plasmodium falciparum (Pf) malaria transmission in India. A Fuzzy-based Climate Suitability Malaria Transmission (FCSMT) model under the GIS environment was generated using Temperature and Relative Humidity data, extracted from CORDEX South Asia for Baseline (1976-2005) and RCP 4.5 scenario for future projection by the 2030s (2021-2040). National malaria data were used at the model analysis stage. Model outcomes suggest that climate change may significantly increase the spatial spread of Pv and Pf malaria with a numerical increase in the transmission window's (TW) months, and a shift in the months of transmission. Some areas of the western Himalayan states are likely to have new foci of Pv malaria transmission. Interior parts of some southern and eastern states are likely to become more suitable for Pf malaria transmission. Study has also identified the regions with a reduction in transmission months by the 2030s, leading to unstable malaria, and having the potential for malaria outbreaks.

Preparedness for malaria elimination in the wake of climate change in the State of Uttarakhand (India).

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.