Discuss epidemiology of malaria, write briefly about its prevention and control .pptx

Discuss epidemiology of malaria, write briefly about its prevention and control

1. Discuss epidemiology of malaria, write briefly about its prevention and control

2. Introduction Malaria is a communicable disease caused by protozoan parasites of genus Plasmodium Transmitted to man by certain species of infected, female Anopheline mosquitoes. The disease is characterized by intermittent or remittent febrile paroxysms occurring on alternate days (tertian) or daily (quotidian). A typical paroxysm has an initial short ‘cold’ stage of shivering when patient gets himself covered with blankets and quilts, followed by the long ‘hot’ stage when rapidly increasing temperature shooting up to 39° to 40°C makes the patient throw them off and finally the ‘wet’ stage when profuse sweating brings down the temperature. 

3. Epidemiological factors Epidemiological triad

4. Agent factors Caused by hemoparasites of genus: Plasmodium Four species P. vivax : commonest P. falciparum : commonest P. malariae : focal distribution P. ovale : rare Cyclopropagative lifecycle of mosquito occurs in 2 stages Sexual stage in mosquito Asexual stage in human host

5. LIFECYCLE OF MALARIA PARASITE

6. Reservoir of infection Human Exception – Chimpanzees in tropical Africa Period of communicability Once the gametocytes mature and in present in sufficient density P. vivax appear in peripheral blood 3 to 5 days after the initial appearance of the asexual forms of parasites where as in falciparum infections they do not appear until 10-14 days after the first appearance of asexual parasites.

7. Host Factors Age- all ages are equally affected Sex- no difference Race- Black people with sickle cell trait – immune to P.falciparum G6PD deficiency – suffer more from P.vivax infection Economic status: low socio economic status, poor lighting Movements Migration, natural calamities Habits Sleeping outdoors, ignorance. Immunity No natural immunity, maternal antibodies provide immunity for first 3-5 months of birth

8. Environment factors Environmental factors influence the bionomics of the vector species of Anopheline mosquito and the habits of human host. Season- July to November Temperature- optimum temperature – 20 to 30 degree Humidity- higher the humidity – more the mosquitoes are active Rainfall – rain provide good opportunity for breeding , however heavy rainfall has adverse effects Altitude- not found in high altitude areas Man made malaria- burrow pits, gardens, construction sites, plastic bottles, water dams.

9. Vectors of Malaria 63 species of anopheline mosquito In India- only 6 primary vectors and 3-4 secondary vectors Resting habits Indoor: endophily Outdoor: exophily Time of biting: nocturnal: between dusk and dawn Flight range: 0.5 km to 8 km An.baimaii – 0.5 km An.minimus and fluviatilis- 1km An.culicifacies and stephensi- 2km An.sundaicus- 8km Breeding places

10. Species Distribution of Anopheles in India

11. Mode of transmission Vector transmission Direct transmission Congenital transmission Incubation period 9-14 days: falciparum 9-17 days: vivax 18-40 days: quartan malaria 16-18 days: ovale malaria

12. Clinical features

13. Diagnosis Microscopy Thin and thick film Serological tests Rapid diagnostic test

14. Prevention and control Stratification of problem Vector control strategies Anti adult measures Residual spraying: malathion, fenitrothion Space application: malathion Individual protection: mosquito nets, repellants Anti larval measures Larvicides: deltametrin Source reduction: reducing mosquito breeding sites Integrated control