The following major eco-epidemiological types can be distinguished:
- Forest, forest-fringe and hill-tract malaria found in the eastern and north-eastern states. Transmission is intense and perennial. The populations are often “tribes” living in or near forests with a more or less nomadic life-style.
- Rice-field malaria which is often highly seasonal with low to moderate transmission. In the arid north-west, rice-field malaria declines to epidemic-prone desert-fringe malaria.
- Urban malaria has been a steadily increasing problem in India since the 1950s and is largely related to changing urban ecology with construction activities, which attract workers from poor rural endemic areas. Malaria related to development projects, e.g. road-building, is conditioned by similar factors.
At the time of independence in 1947, there were an estimated 75 million malaria cases and 0.8 million deaths annually. National Malaria Eradication Programme was launched in 1958, based mainly on widespread DDT spraying. The number of reported cases was reduced to about 100,000 by 1965-66. After global eradication was called off in 1969, funding decreased steeply, and by 1976 reported cases peaked at 6.47 million. In 1977, a Modified Plan of Operation was launched with the immediate objectives of preventing deaths and to reduce morbidity due to malaria. The programme was “integrated with primary health care”.
The blanket approach of insecticidal spraying was changed to selective indoor residual spraying targeting with Annual Parasite Incidence (API) of 2 per 1000 per year and above. The number of cases declined to 1.91 million in 2004 (figure 2). However, the proportion of cases due to P. falciparum has risen steadily in the 1980s. In the face of a generally decreasing case-load, this is a sign of worsening resistance to the treatment being used.