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Malaria in Koraput district of Orissa
Insights
Malaria prevalence in Koraput, Orissa, was 13%, with young children most affected. High incidence suggests significant acquired immunity in this tribal population.
Area of Science:
- Epidemiology
- Public Health
- Tropical Medicine
Background:
- Malaria remains a significant public health challenge, particularly in tribal regions of India.
- Understanding malaria's epidemiology in diverse populations is crucial for targeted interventions.
Purpose of the Study:
- To investigate the incidence and prevalence of malaria in the tribal district of Koraput, Orissa.
- To identify high-risk age groups and tribal communities for malaria infection.
- To explore potential factors influencing malaria transmission and immunity.
Main Methods:
- Conducted mass blood surveys in 61 villages, examining 12,122 individuals.
- Performed fever surveys over one year in 22 villages, collecting 5,511 blood samples.
- Assessed splenomegaly in 2,554 children under 10 years of age.
Main Results:
- Overall malaria parasite positivity was 13% (1,604/12,122).
- Children aged 2-4 years exhibited the highest parasite rates (27.2%) and incidence (457/1000).
- Plasmodium falciparum was the predominant species (80%), followed by P. vivax (10%).
- Spleen rates in children aged 2-9 years were 22%, with no correlation to parasite species.
- Annual parasite incidence (API) was 89.5 per 1000 population.
- Malaria prevalence and splenomegaly were higher in Bonda, Kondh, and Poroja tribal children.
Conclusions:
- The age-specific patterns of malaria prevalence and incidence suggest a high level of acquired immunity within the population.
- Significant variations in malaria burden exist among different tribal communities, highlighting the need for community-specific strategies.
- Genetic factors may play a role in malaria susceptibility and resistance within these tribal groups.
Abstract:
Incidence and prevalence of malaria was studied in the predominantly tribal district of Koraput, Orissa state. In the mass blood surveys in 61 malarious villages, a total of 12,122 persons were examined and 1,604 (13%) were found positive for malaria. Infant parasite rate was 23% and young children 2-4 years old were the worst affected (parasite rate 27.2%). P. falciparum, P. vivax, and P. malariae accounted for 80, 10 and 3% respectively of all infections. A sample of 2,554 children below 10 years of age were examined for splenomegaly. The spleen rate in 2-9 year old children was 22% and the average enlarged spleen (AES) was 2.06. There was no association between size of the spleen and species of parasite. Fever survey was done for a year in 22 villages and 5,511 blood samples were collected of which 24.8% were positive for malaria parasite. The annual parasite incidence (API) was 32.4 per 1000 infants and 89.5 per 1000 population. Children, 2-4 years old recorded the highest incidence (457/1000). The age pattern of prevalence and incidence indicate high level of acquired immunity in the population. Prevalence and incidence varied among different tribal communities. Prevalence of infection and splenomegaly was higher among children of Bonda, Kondh and Poroja tribes. The role of genetic factors in malaria is discussed.