GIS based malaria information management system for urban malaria scheme in India.

A GIS based information management system has been developed to help Urban Malaria Control in India. The basic objective is to develop a model to assist planning and implementation of a suitable control measure. The system can help in: (i) identifying high receptive areas in time and space domain; (ii) identifying risk factors for high receptivity; (iii) monitoring and evaluating control measures. To demonstrate this system, information on 33 parameters and malaria cases has been attached to a digitised map of Dindigul, an urban town in Tamil Nadu. Functionalities of the system and its utility are described in this paper. A GIS based information management system ensures that if a localised spurt of the disease occurs, it can be associated rapidly with a likely cause, a specific vector, and a probable human source, so that appropriate preventive action can be taken to arrest any rising trend.

Spiracular indices in Anopheles stephensi: a taxonomic tool to identify ecological variants.

Thoracic spiracle length and its index was examined for their ability to discriminate two ecological variants, type form and mysorensis, of Anopheles stephensi in the adult stage. The type form is exclusively domestic in all seasons, whereas the mysorensis variant occupies the outdoor niche during monsoon and postmonsoon seasons, with spillover into domestic sites during summer ecological stress periods. A statistically significant co-relation was established between the ridge count of the egg and two adult measurements, the thoracic spiracle length, and the spiracular index. In An. stephensi type form, average spiracle length was 0.11-0.12 mm and average spiracular index was 8.09-9.23, whereas in mysorensis, the corresponding figures were 0.09-0.10 mm and 6.82-7.60. These parameters showed consistent variations in population of mosquitoes that emerged during monsoon and summer season. The thoracic lengths in both variants remained constant, and only spiracular lengths showed fluctuations in three seasonal populations. These measures provide discrimination of adult variants--identifications that are essential in malaria control programs.

Malaria paradigms in India and control strategies.

The paper gives a brief history of malaria control in India through the National Malaria Control Programme (NMCP), National Malaria Eradication Programme (NMEP), implementation of the Modified Plan of Operation (MPO), strengthening of malaria control by launching P. falciparum Containment Programme (PfCP) and the Urban Malaria Scheme (UMS). Making reference to various evaluations of the NMEP, the paper analyses the present malaria situation and brings out reasons demanding change in the strategy of malaria control in consonance with the global malaria control strategy of the World Health Organization (WHO). The epidemiological analysis has revealed that the present adverse malaria situation concentrates mostly under the following five epidemiological paradigms viz. (i) tribal malaria, (ii) rural malaria, (iii) urban malaria, (iv) industrial malaria, and (v) border malaria. Malaria control requires specific approaches and control strategies for each paradigm. We have suggested changes/augmentation in the organizational set-up beginning from NMEP Directorate to the most peripheral health units. The primary responsibility of malaria prevention and control including cost in developmental projects should be shared by the corporate sectors through intersectoral coordination. Residual problems during maintenance phase of the project would come under the general health services. International and bilateral cooperation increases resources availability. The available tools and their rational use for malaria control in different epidemiological paradigms has been discussed with emphasis on integrated control, selective use of chemical insecticides and adoption of cost-effective and sustainable malaria control methods. In this context, intersectoral collaboration, community participation, training, operational research and health education have been discussed as the vital components for effective malaria control.

Management of admitted malaria cases in four major hospitals of Delhi: a case study.

A hospital-based retrospective case study of admitted patients was undertaken in four major hospitals of Delhi during 1991, with a view to assessing (i) recording and reporting system of malaria cases, (ii) diagnostic criteria being followed, (iii) management of complicated and severe malaria cases, and (iv) availability of life-saving antimalarials. The study showed that none of the hospitals either followed the international coding system for recording or adopted the National Malaria Eradication Programme guidelines for diagnostic criteria malaria, i.e. by blood smear examination. Diagnosis of malaria in three out of four hospitals was not preceded by blood examination in all cases. Only 55% of the 283 clinically suspected malaria cases were screened for malaria parasite with overall positivity of 20.14 per cent and of 38.25 per cent in examined cases. Age and sex break-up indicated that males suffered more and 65 per cent of the patients belonged to 16-40 years' age groups as compared to 38.4 per cent population falling in this age group according to 1981 census. Out of 263 recovered study cases, 13 per cent came from adjoining states while this percentage went up to 35 per cent (7 out of 20 cases) in the case of malaria deaths. Over 80 per cent of the clinically suspected cases presented with signs and symptoms of fever or fever with rigour, chills or vomiting. In 38 per cent of the cases there was a definite time lag in reporting of the cases to hospitals but most of the cases (91 per cent) were administered antimalarials within 24 h of admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical appraisal of entomological data of Madhya Pradesh for 1991 and its relevance to the National Malaria Eradication Programme.

Entomological data generated in five entomological zones, of Madhya Pradesh State during 1991 including, Bhopal, Bilaspur, Gwalior, Indore and Raipur were analyzed. The entomological parameters that were studied included per man hour (pmh) density, abdominal physiology and parity status. The inferences were related to i) resting behaviour (exophily/endophily) ii) duration of indoor resting period of mosquitoes iii) man-vector contact iv) efficacy of residual insecticide and v) vulnerability of the area to focal malaria outbreaks. The data chiefly pertains to the putative malaria vector Anopheles culicifacies in all the five zones under study. The studies have brought out that A. culicifacies, traditionally endophilic and endophagic, has demonstrated radical departure in its resting and feeding behaviour. In Gwalior zone the species shows high preference for exophily. In Bhopal and Indore zones there is differential resting behaviour with respect to season. The species shows, for most part of the year exophily but is also endophilic during post monsoon period. In Bilaspur zone the species shows marked exophily and endophagy. Irrigation practices seem to have affected the mosquito population density patterns in these regions as brought out in Indore and Bilaspur zone, where high density pattern is observed between November and February. These findings have obvious implications in selecting the appropriate intervention methods and the period of spray in areas where residual spray is the method of choice for interruption of transmission.

Epidemic of malaria in Barmer district (Thar desert) of Rajasthan during 1990.

Barmer district of Rajasthan in Thar desert and hitherto a hypoendemic area for malaria came in the grip of a severe malaria epidemic during 1990. The epidemic occurred as an aftermath of floods, preceded by normal rains during 1988 and 1989 after a prolonged drought phase. The epidemic was spread over the whole district including Barmer town. Annual Parasite Incidence (API) and Annual falciparum Incidence (AFI) for the district touched record figures of 17.20 and 5.83 respectively while for the Barmer town they were 36.5 and 14.0 respectively. Out of the eight PHCs, Baitu PHC was the worst affected where the two indices touched all-time high figures of 55.3 and 19.6 per cent respectively. A total of 122 infants were reported positive for malaria, of which 103 were contributed by Baitu PHC alone. Eighty per cent infant positivity was spread over September and November, indicating a high rate of transmission. A total of 47 deaths due to cerebral malaria were reported. However, in view of the high infectivity among infants and paediatric groups there was a strong possibility of deaths among these groups which could not be verified. Entomological findings revealed that a sudden increase in An. culicifacies densities due to extensive breeding potential, as a sequel to floods, activated the transmission, which was maintained at a low level by An. stephensi, predominant in this desert region. Other factors which contributed to the intensity and extent of epidemic were the return of drought-migrated population from malarious areas, low cattle density, malaria non-immune population, inadequate and poor spray coverage and delayed radical treatment. Insecticide adult susceptibility tests revealed a high degree of resistance in An. stephensi against DDT and dieldrin.

Development of a methodology for malariogenic stratification as a tool for malaria control.

Modified plan of operation (MPO) for malaria control launched in 1977 failed to curb malaria incidence beyond about 2 million cases per annum and thus necessitated development of multipronged malaria control strategies based upon malariogenic stratification. A model for such stratification based upon six most sensitive, but quantifiable, epidemiological parameters for which records are easily available at PHC level, namely, topography, average annual rainfall, vector(s), average annual parasite incidence (API) for the last five years, epidemic potential and vulnerability was developed. This model has been successfully tried in the State of Karnataka and on that basis the whole State has been divided into five strata in order of increasing endemicity. Objectives of malaria control for each of the stratum so defined have been proposed.

Malaria as anthropo-ecosystem (MAES): Part V. Self-regulation and stability of MAES.

In biological ecosystems, population tends to fluctuate above or below asymptotic level or the 'carrying capacity'. Self-regulation is achieved by extrinsic, that is, environmental limiting factors and intrinsic, that is, physiological and genetic factors. In Malaria Anthropo-Ecosystem (MAES) which is much more intricate and complex system, Plasmodium being endoparasite is required not only to interact with intrinsic factors of its vertebrate and invertebrate host but also to regulate itself to environmental factors to which its both the hosts are subjected. Attempt has been made to provide, on the basis of present knowledge, the probable explanation of self-regulatory mechanisms from molecular, cell, organ/organism, population/community levels of vertebrate and invertebrate hosts which give stability to MAES as a whole system.

Malaria as Anthropo-Ecosystem. Part IV. Adaptation of elements of MAES.

Adaptations have been recognized as an essential facets of evolution. These broadly cover two types exemplified by change (adjustments) and that leads to creation of new species. The former is generally in response to environmental factors, while the others are genetic and heritable and enable the population to continue its existence. These are also accompanied by biological and behavioural changes. In the study of MAES, adaptations appear to be main mechanism which facilitate the dynamics of the malaria system in time and space. Schematically, three broad groups of resultant factors of adaptations within MAES. viz. genetical, biological and environmental have been identified and briefly discussed with regard to their diversity in all the three elements of MAES.

Malaria as anthropo-ecosystem. Part III: Diversity of MAES.

Diversity being one of the main characteristics of Malaria Anthropo-Ecosystem (MAES) is reflected in time and space. Temporal diversity of MAES generally may be divided into two types--long time periods usually on a global scale, and various local fluctuations expressed as malaria periodicity. Geographical confinement of MAES is determined by interactions of various elements of the latter with biotic and abiotic components of the environment. The diversity of the MAES within climatic zones of South and South-East Asia is shown to be of many types of sub-systems depending, apart from climatic conditions, on types of human activity in those ecosystems.