Sustainable control of malaria employing Gambusia fishes as biological control in Jalore and Barmer districts of Western Rajasthan

Sardar Sarovar Irrigation Canal system was constructed by Narmada Valley Development Authority (NVDA) to cater to drinking water as well as for irrigation purposes in Jalore and Barmer districts of Western Rajasthan. To cater to the needs of water for the villagers in the command areas, ‘Diggies’ (surface water tanks) with ‘Sumpwells’ (water supply surface tanks) were installed. In a health impact assessment study of the irrigation canals from December 2010 to February 2016, the breeding of two major malaria vectors. An. culicifacies and An. stephensi were observed in diggies and sumpwells. As a biological control, Gambusia affanis fishes were employed for larval control in such stagnated water sites during the intervention phase viz. February 2012 in 251 diggies and 251 sumpwells. A significant reduction of breeding in diggies (99.54%) and sumpwells (97.81%) was observed. The positivity and larval density (dip index) were monitored in the control from up to February 2016 for their sustainability.

A spatial statistical approach to analyze malaria situation at micro level for priority control in Ranchi district, Jharkhand.

Background & objectives: The presence of efficient malaria vectors namely Anopeles culicifacies, An. fluviatilis and An. annularis (Diptera: Culicidae), rapid industrialization causing large influx of population and poor health infrastructure are some of the factors that make malaria an important public health problem in Ranchi, the capital of Jharkhand State, India. A geographical information system (GIS) based retrospective study using spatial statistical tools was initiated in 328 subcentres of 14 primary health centres (PHCs) of the district using malaria epidemiological data of three years (2007-2009) to identify spatial distribution pattern of Plasmodium vivax (Pv) and Plasmodium falciparum (Pf) occurrence, delineation of hot spots and to map directional distribution trend of Pf spread to help formulate evidence-based policy and to prioritize control during 2011. Methods: Spatial statistics tools like Global Moran's I index, Getis-Ord Gi* and Standard Deviational Ellipse were used in GIS domain for analysis. Results: Spatial distribution pattern of Pv occurrence was found random while Pf distribution was significantly clustered. During 2007-2009, the number of subcentres under Pf hot spot category exhibited downward trend while high Pf risk subcentres exhibited upward trend. One consistent Pf hot spot consisting of five subcentres was identified in Silli PHC. During 2009, one Pf hot spot consisting of 20 subcentres and 18 subcentres under high Pf risk category were identified in Angara, Silli, Burmu and Kanke PHCs. A shifting trend in Pf spread was noticed from north-west to western direction from 2008 onwards. Interpretation & conclusions: The study recommended priority control in 20 Pf hot spot and 18 high Pf risk reporting subcentres including five consistent Pf hot spot subcentres in Angara, Silli, Burmu and Kanke PHCs during 2011 to address grave malaria situation in the district in a cost-effective manner.

Resting behaviour of Anopheles stephensi type form to assess its amenability to control malaria through indoor residual spray.

Background & objectives: In the present study, an attempt was made to find reasons of ineffectiveness of indoor residual spray to interrupt malaria transmission by investigating the behaviour of two variants of Anopheles stepnesi, viz. type form and mysorensis in rural areas of Rajasthan, India. Methods: Both low malarious (DDT spray from 1958 to 1976) and high malarious (DDT spray from 1958 to April 2006) villages were selected for the study in Arid zone district Jodhpur, Rajasthan during March–April 2006. Resting behaviour of the species during all its movement rhythms covering 24 h period related to: (i) swarming/ mating; (ii) pre- and post-biting rest; (iii) after feed resting between hoping movements; (iv) night and day time resting and; (v) diel activity movements in response to temperature changes, were carried out. Results: The results showed that household objects like cupboards, furnitures, hanging clothes, goods stacked on loft, stored clothes, cobwebs and floor were the dominant resting sites both in sprayed and unsprayed villages. About 95 and 97% of An. stephensi preferred to rest on household objects of unsprayed and sprayed villages respectively. There was no significant difference in resting behaviour of the species in both groups of villages (p >0.05). The pre-biting resting time was recorded as 5 to 15 min whereas post-biting resting time lasted for 15 to 25 min. After biting outdoor (in courtyard – open to sky) species starts entering the rooms at around 2330 hrs. It was observed that during III quarter (0100 to 0400 hrs) maximum species entered into the room were 56% in unsprayed and 62% in sprayed villages. Statistically there was no significant difference in the entry of mosquitoes (p >0.05) in both the groups of villages. Conclusion: Before DDT era, An. stephensi was found resting at all heights of the walls inside the human dwellings. Present study revealed that An. stephensi is trying to avoid sprayable surfaces and tend to rest on unsprayable surfaces during all its movement rhythms starting from swarming, pre-/post-biting and during hopping movements in the courtyard and thereafter household objects inside the room as final day time resting. It was concluded that changed behaviour of resting of An. stephensi on unsprayable objects in sprayed rooms largely accounted for failure of malaria control. Control of An. stephensi, thus requires an integrated vector control strategy based upon interesectoral, environmental, larviciding with chemical/biolarvicide and use of larvivorous fish wherever feasible. Such a control strategy offers cost-effective and sustainable option than indoor residual spray.

Retrospective study of chikungunya outbreak in urban areas of India.

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.

Application of spatial technology in malaria research & control: some new insights.

Geographical information System (GIS) has emerged as the core of the spatial technology which integrates wide range of dataset available from different sources including Remote Sensing (RS) and Global Positioning System (GPS). Literature published during the decade (1998-2007) has been compiled and grouped into six categories according to the usage of the technology in malaria epidemiology. Different GIS modules like spatial data sources, mapping and geo-processing tools, distance calculation, digital elevation model (DEM), buffer zone and geo-statistical analysis have been investigated in detail, illustrated with examples as per the derived results. These GIS tools have contributed immensely in understanding the epidemiological processes of malaria and examples drawn have shown that GIS is now widely used for research and decision making in malaria control. Statistical data analysis currently is the most consistent and established set of tools to analyze spatial datasets. The desired future development of GIS is in line with the utilization of geo-statistical tools which combined with high quality data has capability to provide new insight into malaria epidemiology and the complexity of its transmission potential in endemic areas.

Operational feasibility of rapid diagnostic kits & blister packs use for malaria control in high transmission areas of Orissa & Chhattisgarh.

BACKGROUND & OBJECTIVE: Early diagnosis and prompt treatment of cases with malaria are two important components of malaria control strategy. The independent assessment of the operational feasibility of rapid diagnostic kits and blister packs for malaria in some selected high transmission areas of Orissa and Chhattisgarh was done with the objectives to assess the knowledge and skills of the paramedical personnel and their acceptability by the paramedical personnel and the community, and to assess improvement in patients' health seeking behaviour. METHODS: The basic information regarding malaria situation, epidemiological divisions, distribution data of rapid diagnostic kits and blister packs, etc., was collected from State and district headquarters. The subcentres from the primary health centres/community health centres were selected on the basis of supply of rapid diagnostic kits and blister packs. The subcentres were visited and health personnel interviewed about their knowledge and skills on the use of rapid diagnostic kits and blister packs. A cross-sectional survey was conducted to assess the public opinion about rapid diagnostic kits and blister packs. RESULTS: We found that the paramedicals were well trained in the use of rapid diagnostic kits and blister pack administration and the acceptance was good by both paramedicals and general public. The compliance rate of radical treatment with blister packs was 100 per cent and no adverse events were reported. INTERPRETATION & CONCLUSION: Our findings showed that rapid diagnostic kits and blister packs under remote and inaccessible highly malarious areas can be introduced that will have significant impact in reducing malaria morbidity and mortality.

Bioecology of An. philippinensis in Andaman group of islands.

Studies on bioecology of An. philippinensis a vector of malaria was carried out in eight islands of the Andaman group. It was found that An. philippinensis preferred to rest and bite outdoors. Maximum biting was observed during 1800 to 2100 hrs on both cattle and human bait. The maximum breeding of An. philippinensis was recorded in slow moving stream followed by ponds with vegetation. The breeding sites infested with Chara and Spirogyra algae were most favourable whereas, with Lemna and Oscillatoria were unfavourable for the proliferation of this species. The breeding association of An. philippinensis was found with other seven anopheline species in different breeding habitats.

Geographic information system as a tool to study malaria receptivity in Nadiad Taluka, Kheda district, Gujarat, India.

Nadiad taluka, Kheda district, Gujarat State, India, comprising of 100 villages with unstable malaria and periodic epidemics, was selected for the study. Using topo sheets and satellite imageries thematic maps on water table, water quality, hydro-geomorphology, soil type, relief, irrigation channels, were prepared, overlaid and integrated sequentially using Arclnfo software. The composite map resulted in 13 stratification classes. Stratification classes 1-12 fell in non-irrigated tracts and exhibited 95% matching of areas of high receptivity as revealed by geographical information systems (GIS) and annual malaria parasite incidence (API). Stratification class 13, an irrigated area, showed poor matching but the ground verification established low receptivity of the area. Thus the study resulted in complete reconciliation of cause and effect relationship as established as per GIS in explaining malaria epidemiology. In general, the study revealed that high malaria in villages of Nadiad is mainly due to high water table, soil type, irrigation and water quality. Based on local malaria transmission determinants, a revised malaria control strategy has been suggested.

Estimation of larval production in Sanjay Lake and its surrounding ponds in Delhi, India using remote sensing technology.

A feasibility study to use remote sensing techniques for estimation of mosquito production in Sanjay lake in east Delhi was carried out. Besides the Sanjay lake, larval production for 12 surrounding remote sensing identifiable ponds was also estimated. Inspite of some limitations the technique is very useful for rapid mapping of major breeding sites, recording temporal changes and estimation of larval production in a cost effective manner in terms of survey cost and time.