What is the incidence of malaria in South India?

Incidence of Malaria in South India

Nearly 14% of the Indian population is at high-risk for malaria, with over 1 million infections and 2000 deaths each year across India, with South India contributing significantly to this burden. 1

Epidemiological Overview

• Malaria remains a significant public health challenge in South India despite decreasing trends in recent years 2
• The disease is caused by four protozoan species of the genus Plasmodium (P. falciparum, P. vivax, P. ovale, and P. malariae), all transmitted by female Anopheles mosquitoes 1
• In South India, particularly in states like Tamil Nadu, there is a considerable burden of malaria with P. vivax being the dominant species (70.8% in Chennai) 3

Regional Distribution and Incidence Patterns

• Studies in Chennai (Tamil Nadu) showed malaria prevalence of 3-8% by PCR in community surveys, with P. vivax dominating (70.8% of infections) 3
• Odisha state, part of eastern India bordering South India, shows higher prevalence rates with up to 18% of the population carrying malaria parasites when tested by PCR 4
• There is significant heterogeneity in malaria transmission between and within states of India, with various ecotypes and paradigms of malaria recognized 2

Submicroscopic and Asymptomatic Burden

• A proportionally high burden of asymptomatic (71%) and submicroscopic (71%) infections was detected in community surveys in Chennai 3
• This hidden reservoir of infection poses a significant challenge to malaria elimination efforts in South India 4
• The prevalence of Plasmodium species among asymptomatic individuals detected using qPCR (18%) is significantly higher than that detected by microscopy examination (5.5%) or rapid diagnostic tests (7.3%) 4

Seasonal Variation

• Malaria in South India shows seasonal variation with peak transmission typically occurring after the monsoon season 5
• Maximum prevalence of malaria in most parts of India is from July to November, with rainfall providing breeding grounds for mosquito vectors 5
• This seasonal pattern indicates unstable transmission of malaria in many regions of South India 5

Risk Factors and Vulnerable Populations

• Rural populations are more vulnerable to malaria infection compared to urban dwellers 6
• Lower socioeconomic groups bear a disproportionate burden of malaria in South India 6
• Young adults under 45 years of age constitute the majority (84%) of malaria patients in some regions 6
• Ethnic tribes living in forested areas of states like Odisha contribute significantly to the morbidity and mortality due to malaria 2

Challenges to Malaria Control

• Drug resistance and insecticide resistance are emerging challenges for malaria control in South India 2
• Lack of accurate knowledge about the true disease burden complicates control efforts 2
• Limited use of preventive measures such as mosquito nets (14%), repellents (13%), and protective housing features (7%) contributes to ongoing transmission 6
• The high proportion of submicroscopic and asymptomatic infections serves as a reservoir for continued transmission 3, 4

Impact on Public Health

• Malaria continues to cause significant morbidity and mortality in South India despite control efforts 2
• The disease has devastating socioeconomic consequences, particularly affecting the working-age population 6
• The pattern of clinical presentation has changed with multi-organ failure being more frequently observed in falciparum malaria 2
• There are increasing reports of P. vivax presenting with severe manifestations in South India 2