Transmission, control & elimination

Malaria transmission

Photo: MMV

In India, malaria is transmitted by nine Anopheline species, although six of these are primarily responsible for transmission in India (Anopheles culicifacies, Anopheles stephensi, Anopheles dirus, Anopheles fluviatilis, Anopheles minimus and Anopheles epiroticus).1

The two main malaria parasites in the country are P. falciparum and P. vivax, however incidences of malaria from P. ovale and P. malariae have also been reported in some areas of the country.1 51% of malaria cases in India are as a result of P. vivax infection while about 48% are from P. falciparum and the rest from other Plasmodium parasites or mixed infections.2 P. falciparum used to be the dominant parasite, but this has changed in the last few years.2

P. vivax occurs mainly in the plains while P. falciparum is mostly prevalent in forested and peripheral areas.3

Maximum transmission of malaria takes place during the June to September monsoon season. From the October to December following the monsoon period, collection of rainwater in pits and puddles creates breeding grounds for mosquitoes which increases transmission.3

Malaria control and elimination

Given the varying nature of the malaria burden across India, malaria control and elimination is very segmented and the country has divided the different areas into four categories (using annual parasite incidence as the primary criteria) by the National Framework for Malaria Elimination (NFME) and will adopt a phased approach towards malaria elimination.3

The district is used as the unit of planning and implementation of malaria elimination programmes. Each state is responsible for classifying its districts according to the defined categories so that states that have met the criteria for the elimination phase may initiate elimination phase activities prior to those that have not met the criteria.3

Classification of states and union territories (UT) based on annual parasite incidence (API)

S. No. Categories of states/UTs Definition
1. Category 0: Prevention of re-establishment phase States/UTs with zero cases of malaria.
2. Category 1: Elimination phase States/UTs (15) including their distracits reporting an API of less than 1 case per 1000 population at risk.
3. Category 2: Pre-Elimination phase States/UTs (11) with an API of less than 1 case per 1000 population at risk, but some of their distrcits are reporting an API of 1 case per 1000 population at risk or above.
4. Category 3: Intensified control phase States/UTs (10) with an API of 1 case per 1000 population at risk or above.