Malaria(Plasmodium falciparum)- Epidemiology, Life Cycle, Prevention and Eradication

Malaria(Plasmodium falciparum)- Epidemiology, Life Cycle, Prevention and Eradication.
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1. Malaria ( Plasmodium falciparum )- Epidemiology, Life Cycle, Prevention and Eradication Sarath

2. Epidemiological Triad Host 1.Sex-Male 2.Race-Sickle cell trait 3.Occupation-Labourers,Farmers,Tribals 4.Socio Economic status 5.Human Habits -Nomadism Environment 1.Seasons 2.Temperature 3.Humidity 4.Rainfall 5.Altitude Agent Factors 1.Parasites 2.Reservoirs 3.Relapses Vector Anopheles Mosquito

3. Organism Plasmodium Falciparum Phylum : Apicomplexa Class : Sporozoea Subclass : Coccidia Order : Eucoccidia Suborder : Haemosporina

4. Features of plasmodium falciparum Forms in the peripheral blood- Rings and crescents only. Ring form- Cytoplasm fine and regular. Often with 2 nuclei. Form accole. Merozoites- 18 to 24 or more. Arranged in a grape like cluster. Gametocyte- Banana shaped. Larger than the red blood cell.

5. Life Cycle Exogenous Phase(in Mosquito) Sexual Cycle ( sporogony ) Endogenous Phase(in Human) Asexual Cycle( Schizogony ) Sporozoites pass through body cavity,salivary glands Exoerythrocytic cycle multiplication in liver parenchymal cells Merozoites Enter RBC Ring Trophozoite Mature Trophozoite Immature Schizont Mature Schizont Microgametocyte (differentiation) Macrogametocyte Human blood enters mosquito Microgamete (fertilization) Macrogamete Zygote Ookinete (motile Zygote) Penetrates to outer layer of stomach wall of mosquito and encysts Oocyst grows(multiple division stage: cyst bursts to release sporozoites Sporozoites in saliva injected into human host

6. Malaria Life Cycle in Humans

7. Reservoir Conditions : The person must harbour both sexes of gametocyte in blood Gametocytes must be mature Gametocytes must be viable Gametocytes must be present in suffcient quantity

8. Reservoir Contd … Humans 1. One who harbours the sexual forms of parasite. 2. Children are more likely to be gametocyte carriers than adults. Hence better reservoir.

9. Transmission Vector Transmission Anopheles culicifacies – Rural and per urban areas Anapheles stephensi -- Urban and Industrial areas Anopheles fluviatilis -- Hilly areas Anopheles epiroticus -- Only in Andaman and Nicobar

10. 2. Direct Transmission By sharing syringes, blood transfusion etc.

11. Parasites keep their infective activity during at least 14 days in bottles stored at -4 C Persons who have lived in endemic area and anyone who has had malaria should not be accepted as a blood donor until 3 years afterwards.

12. 3. Congenital Malaria Congenital infection from mother to newborn also occur, but it is comparatively rare

13. Prevention All that we have to do is to break this chain

14. Insecticide treated nets Repellents protective clothing screening of houses Environmental sanitation water management drainage Larviciding of water surfaces intermittent irrigation slucing , biological control Indoor residual spraying Space spraying Ultra low volume sprays Health e ducation Community participation Prophylaxis for susceptible population Gametocidal drugs

15. Prevention Action For Individual and Family protection Reduction of Human-Mosquito contact Insecticide treated nets, repellents, protective clothing, screening of houses Destruction of mosquito larva Peri -Domestic sanitation Source reduction Small scale drainage Social participation Motivation for personal and family protection Destruction of Adult Mosquitoes Indoor residual spraying

16. Prevention Action For Community protection Reduction of Human-Mosquito contact Insecticide treated nets, zooprophylaxis Destruction of mosquito larva Larviciding of water surfaces, intermittent irrigation, sluicing, biological control Source reduction Environmental sanitation, water management, drainage Destruction of Adult Mosquitoes Indoor residual spraying, Space spraying, ultra low volume sprays Social participation Health Education, Community participation

17. Biological Control- Gambusia

18. Insecticide treated nets

19. Can malaria be Eradicated??? Agent Source Susceptible Population Vector Eradication Elimination Control

20. Current answer is NO  Why?? D espite progress, the burden of malaria is still great and it is widespread . Drug and insecticide resistance are on the rise. In S outh East Asian countries, resistance of  Plasmodium falciparum,   to Artemisinin , has been detected. Although new drugs and insecticides are being sought, none are expected to be available in the near future. Ref: Malaria eradication:Is it possible?Is it worth it?Should we do it?Should we do it? Jenny Liu,Sepideh Modrek,Roly D Gosling,Richard GA Feachem

21. Increased mobility of people not only makes containment of resistance difficult, but also threatens the introduction or reintroduction of malaria parasites to receptive areas . New strains are emerging- ex. Plasmodium knowles i Zoonotic reservoirs Ref: Malaria eradication:Is it possible?Is it worth it?Should we do it?Should we do it? Jenny Liu,Sepideh Modrek,Roly D Gosling,Richard GA Feachem

22. How can we bring eradication in the future??? Malaria is biologically and ecologically different throughout the world. So Malaria eradication strategies should be developed and implemented on a local or regional level . Eradication can be accelerated by new drug regimens and strategies that lead to complete parasitologic cure of the individual . The majority of malaria infections occur in asymptomatic people, who are a source of continued transmission. A successful and accelerated eradication effort will target asymptomatic infections through community-based efforts.

23. Thank You