1 / 50

Malaria

Malaria. Dr R.N.Roy Associate Professor Department of Community Medicine. Malaria. A febrile illness caused by asexual plasmodium parasite transmitted by infected female anopheles mosquito Plasmodium genus of parasite infect RBC in human Occasional infections of monkey with P. knowlesi ,.

elisha
Download Presentation

Malaria

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Malaria Dr R.N.Roy Associate Professor Department of Community Medicine

  2. Malaria • A febrile illness caused by asexual plasmodium parasite transmitted by infected female anopheles mosquito • Plasmodium genus of parasite infect RBC in human • Occasional infections of monkey with P. knowlesi,

  3. Magnitude of problems • About half the world’s population (3.3 billion) in live in areas(109 countries & territories) endemic for malaria • Estimated 247 million malaria cases in 2006, of which 91% were due to Pf • Around 40% of the global population at risk of malaria resides in SEA Region

  4. AFRO: African Region AMRO: Region of the Americas SEARO: South-East Asia Region WPRO: Western Pacific region EMRO: Eastern Mediterranean

  5. Malaria Burden in India • During Pre- control era(1953) Annual Incidence was 75 mil / (22% of population) and 0.8mil death/ yr • During 2008 incidence was 1.53 million & half of these were Pf & 1055 deaths reported • About 88% of malaria cases & 97% of deaths reported from Northeastern (NE) States, Chhattisgarh, Jharkhand, MP,  Orissa,  AP  Maharashtra Gujarat  Rajasthan, W B Karnataka

  6. Problem in India Major epidemiological types in India • Tribal malaria • Urban malaria • Malaria in project area • Border malaria Serious problem in NE states • Perennial malaria transmission • Predominance of falciparum • Drug resistance

  7. EPIDEMIOLOGY OF MALARIA :Agent factors • Four species : (1)P. Vivax – causes BTM (2) P.Falciparum-causes MTM (3) P.Malariae-causes quartan malaria (4) P.Ovale (not in India)

  8. Host factors • Age: Parasitemia is low during infancy due to maternal antibody • During first few weeks show resistance to Pf infection due to fetal Hb • Pregnancy: increase risk in pregnancy :anemia , LBW delivery.

  9. Epidemiology Reservoir of infection: Human • (Exception- chimpanzee in Africa may carry P. malariae) Conditions for a successful reservoir: • Must harbor viable & mature gametocyte of both sexes in sufficient density

  10. Route of transmission • By bite of infected female anopheles mosquito • Blood transfusion, needle stick injury, sharing needles, organ transplantation • Congenital malaria- mother to foetus

  11. Genetic factors • HbF and Thalassaemia protect against malaria • Sickle cell trait (AS Hb) have higher immunity against P. falciparum • Person with ‘Duffy negative ‘ RBC are resistant to vivax infection

  12. Environmental conditions • Urbanization, • Industrialization and construction projects • Consequent migration, • Deficient water and solid waste management • Indiscriminate disposal of articles (tyres, containers, junk materials, cups, etc

  13. LIFE CYCLE OF PLASMODIUMMOSQUITO • Mosquito is definitive host (sexual multiplication takes place) • Mosquito picks up gametocytes from infected person  in gut converted into gamete, zygote, ookinets, oocist, sporozoites finally sporozoites reach the salivary gland (takes about 8- 25 days)

  14. Other factors: • Poor socioeconomic and housing conditions, • population mobility • some human habits like • sleeping out of door • Nomadism • refusal of spray activities etc contribute to causation of malaria .

  15. LIFE CYCLE OF PLASMODIUM IN HUMAN • Man -intermediate host (undergo asexual reprodn.) • Hepatic phase : Mosquito bite  inoculate sporozoites - reaches hepatocyte by 30mts  multiply to form hepatic schizonts  mature to daughter merozoites and released in sinusoids • Erythrocytic phase: Merozoites reach blood stream invade RBC in RBC multiply & develops schzoints  RBC ruptures 48 or 72 hourly releasing cytokinin, TNF pirogens  • Some merozoites convert & develop into gametocyte

  16. Pathophysiology • Incubation period: infective mosquito bite to onset of sign and symptoms = 9-30 days • IP depend upon species of parasite, host immune status, infecting doses and use of antimalarial treatment • Only erythrocytic parasitic stage causes clinical disease • Relapse: after primary attack with out subsequent mosquito bite. • Recrudescence: Reappearance of clinical malaria or M.P in blood, which remain dormant in RBC.

  17. VECTOR Only female Anopheles mosquito carry parasite and infect human

  18. Vector factors for transmission • Vector density • Man biting rate & frequency of blood meal • Time and place of man - mosquito contact • Man - cattle ratio • Flight range • Vector’s susceptibility to infection

  19. IMPORTANT VECTORS OF MALARIA IN INDIA

  20. Critical density for transmission

  21. ENTOMOLOGICAL INDICES  • Vector density (Man Hour Hand Captures ): Nos anopheles collected per man hr. catch • Mosquito infection rate • Man biting rate • Human Blood Index-indicate anthrophilism • Av. nos of larva per dip

  22. ENTOMOLOGICAL INDICES …. PER MAN HOUR DENSITY: No. of mosquitoes collected =--- ---------------------------------------X100 No. of man hours spent in search • High vector density indicates high potential for transmission SPOROZOITE RATE (%): No. of females positive for sporozoites = --------------------------------------------------x 100 Nos. dissected

  23. Suspected case of malaria A patient with fever but without any other obvious cause of fever • Cough and other signs of respiratory infection • Running nose and other signs of cold • Pelvic inflammation indicated by severe low backache, vaginal discharge , urinary symptoms • Skin rash suggestive of eruptive illness • Burning micturition • Skin infections e.g. boils, abscess, infected wounds • Painful swelling of joints • Diarrhoea • Ear discharge

  24. Lab diagnosis: All suspected fever cases be investigated • Blood smear examination/Microscopy • Rapid diagnostic test (RDT)

  25. How & when to use RDT / Smear Exam Where microscopy result is available within 24 hrs.  (Only microscopy done)  Treatment based on slide-result Where microscopy result is not available within 24hrs (Pf RDT + Slide taken) RDT +Ve  Treat Pf  Discard slide RDT –Ve  Slide microscopy  Treatment

  26. EPIDEMIOLOGICAL SURVEILLANCE

  27. ASSESSMENT OF PROBLEM (MALARIOMETRIC MEASUREMENT) • EPIDEMIOLOGICAL SURVEY • Proportional case rate • Spleen rate • Infant parasite rate • Children parasite rate-(% of 2-10 yr children ē MP in blood) • Annual Parasite Incidence (API) • Annual Blood Examination Rate (ABER) • Slide Positivity Rate (SPR) • Slide falciparum Rate (SFR) • Annual falciparum rate (AFR)

  28. Child Spleen Rate(CSR) • % of 2-10 yr children ē enlarged spleen Significance : 25-40%= Endemic >40%=Hyper endemic

  29. Infant parasite rate(IPR) Most sensitive index for recent transmission of malaria. # Positive for MP IPR= -----------------------------------------X100 # Blood slide examined from infants

  30. Annual Blood Examination Rate (ABER) Nos of smears examined & (RDTs +Ve) in a Yr. ABER = ----------------------------------------------------------X100 Total Population under surveillance • Index of operational efficiency of surveillance • ABER should be equal to fever rate in the locality • ABER should be > 10% of population • Monthly Blood Examination Rate should be >1% of population during the transmission season

  31. Annual Parasite Incidence (API) # of +Ve smears & +Ve RDTs in a year API=------------------------------------------------ X 1000 # Population under surveillance • Used to stratify malarious areas • Disease burden in community

  32. Slide Positivity Rate : % of slide positive for parasite Slide Falciparum Rate : % of slide positive for Pf SFR pinpoints areas of Pf preponderance for prioritizing control measures P.falciparum percentage (Pf %)

  33. Surveillance in malaria • Passive Case Detection- Collection of blood slides in Clinic/ institution & treatment. • Active Case Detection- system of detecting malaria cases (blood slide collection ) by HW through domiciliary visits • Mass blood survey- Examination of blood from all persons in a community (during epidemiological investigation around positive cases)

  34. DRUG SCHEDULE FOR MALARIA

  35. Age-specific drug schedules

  36. Chemoprophylaxis Short term chemoprophylaxis (up to 6 wks) (e.g. travelers from non-malarious areas) • Doxycycline 100 mg daily in adults or (1.5mg / kg OD)above in children , started 2 days before reaching endemic area continued for 4 weeks after leaving • Contraindication : Pregnancy & children < 8 years. Chemoprophylaxis for longer stay (> 6 wks) (e.g Military & paramilitary troops in malarious areas duty ) • Mefloquine 250 mg weekly for adults • Mefloquine 5 mg/kg for children • Contraindication of Mefloquine : H/O convulsions, & neuropsychiatric problems

  37. MALARIACONTROL ACTIVITIES & PROGRAMME IN INDIA

  38. Continued..

  39. Continued …

  40. Continued .. Continued ..

  41. NATIONAL ANTI-MALARIA PROGRAMME1999 Under NVBDCP Objectives: • Prevention of deaths due to malaria • Prevention of morbidity due to malaria • Maintenance of ongoing socioeconomic development

  42. Strategies • Surveillance and case management • Case detection (passive and active) • Early diagnosis and treatment • Integrated Vector Management (IVM) • Environmental Management • Stratification of the problem • Area with API<2 • Area with API ≥2 • Community Participation & BCC • Monitoring and Evaluation of the programme

  43. Integrated Vector Management (IVM) • Use of a range of biological, chemical and physical interventions of proven efficacy, separately or in combination, in order to implement cost-effective control and reduce reliance on any single intervention

  44. IVM Includes: • Rotation and & safe use of insecticides including management of resistance • Indoor Residual Spray (IRS) • Insecticide Treated bed Nets (Tins) / Long Lasting Insecticidal Nets (LLINs) • Antilarval measures including source reduction

  45. Vector control methods • Methods of reducing human-vector contact: • Mosquito nets & insecticide treated nets (Synthetic pyrethroid) • House protection with screening of windows, doors etc. • Use of repellents • Anti adult measures: • Indoor residual spraying with DDT/ • Space spraying of insecticides • Anti larval measures: • Larviciding • Biological Control • Source reduction by environmental management

  46. Anti adult measures • Indoor residual spraying with -Organo chlorine compound : DDT - OP-compounds : Malathion, Fenitrothion -Carbamate :Propoxur -Synthetic pyrethroids: Deltamethrin • Space spray: Pyrithrum • Out door space spray :Malathion, Pyrethrum

  47. Anti larval measures • Larviciding with MLO, Temephos ( abate), Fenthion etc. • Biological Control • Use of larvivorous fish (Gambusia affinis & Poecilia reticulata) • Use of biocides: bacillus thuringiensis • Source reduction by environmental management • Drainage /Filling /flushing/change of salinity

  48. Community Perticipation & BCC • Process of learning that empowers people to take rational and informed decisions through appropriate knowledge • Clear messages, communicated through different, credible channels are most likely to bring about change. Ignorance, prejudices must be replaced by knowledge Awareness campaign programme-observe malaria week • Legislative measures: • Model civic bye-laws:

  49. ‘High risk areas’ • Recorded deaths due to malaria • Doubling of SPR during last 3 yrs provided the SPR in 2nd / 3rd yr reaches ≥ 4% • Average SPR of the last 3 yrs ≥ 5% • P.falciparum proportion ≥ 30% provided SPR is ≥ 3% during any of the last 3 yrs • Any area with focus of CQ resistant P.f. cases • Aggregation of labour in project area & new settlements in endemic/receptive & vulnerable areas

  50. Thank you

More Related