Lesson 12 - MALARIA.pptx

malaria notes

1. MALARIA MC 3 LESSON 12

2. L a ver a n

3. Malaria remains the world's most devastating human parasitic infection. Malaria affects over 40% of the world's population. WHO , estimates that there are 350 - 500 million cases of malaria worldwide. In the Philippines there were 3,157 cases in 2022.

4. The malaria life cycle is a complex system with both sexual and asexual aspects . There is an exogenous sexual phase in the mosquito called sporogony during which the parasite multiplies . There is also an endogenous asexual phase that takes place in the vertebrate or human host that is called schizogeny .

5. A complex Life cycle

6. Human Cycle Pre erythrocytic schizogony Ery t hrocytic Schizogony Gametogony Exoer y throcyt i c schizogony

7. Events in Humans start with Bite of Mosquito Man – Intermediate host. Mosquito – Definitive host – Sporozoites are infective forms Present in the salivary gland of female anopheles mosquito After bite of infected mosquito sporozoites are introduced into blood circulation.

8. Pre erythrocytic cycle Sprozoites undergo developmental phase in the liver cell Multiple nuclear divisions develop to Sch i zonts A Schizont contains 20,000 – 50,000 merozoites.

9. Period of Pre erythrocytic cycle 1 P. vivax 8 days 2 P. falciparum – 6 days 3 P. malariae - 13 – 16 days, 4 P. ovale 9 days On maturation , l iver cells rupture to l iberate Merozoites into the blood stream

10. Erythrocyte cycle Merozoites released invade red cells P. vivax infects young erythrocytes P. malariae Infects old erythrocytes P. falciparum infects RBC of all ages The Merozoites are pear shaped and has 1-5 microns in length The receptors for Merozoites are on the red cells glycoprotein

11. Erythrocytic Schizogony Liberated Merozoites penetrate RBC Three stages occur 1 . Trophozoites 2. Schizont 3. Merozoite

12. Exo-erythrocytic (tissue) phase P. malariae or P. falciparum sporozoites do not form hypnoz oit es , develop directly into pre-erythrocytic schizonts in the liver Schizonts rupture, releasing merozoites which invade red blood cells (RBC) in liver

13. Gametogony Merozoites differentiate into Male and female gametocytes They develop in the red cells Found in the peripheral blood smears Microgametocyte of all species are similar in size Macro gametocytes are larger in size.

14. Mosquito cycle Sexual cycle Sexual cycle will be initiated in the Humans by the formation of Gametocytes De v e l op fu r th e r i n the fem a le Ano p h e les Mosquito Fertilization occurs when a Microgametocyte penetrate into Macrogametocyte ZYGOTE is formed matures into OOKINETE OOKINETE to OOCYST OOCYST matures with large number of Sporozoites ( A few hundred to thousands)

15. Mosquito cycle A definitive Host – Mosquito

16. Malaria the disease 9-14 day incubation period

17. Early symptoms The common first symptoms – fever, headache, chills and vomiting – usually appear 10 to 15 days after a person is infected. If not treated promptly with effective medicines, malaria can cause severe illness and is often fatal.

18. Clinical Presentation Stage 1(cold stage) Chills for 15 m ins to 1 hour Cause is due to rupture from the host red cells escap ing into Blood Preset with nausea, vomiting, headache Stage 2 (hot stage) Fever may reach up to 40 c ma y last for several hours.

19. Clinical Malaria Stage 3(sweating stage) Pat i ent starts sweating, concludes the episode Cycl e s a r e fre q uen t ly Asynch r o n ous Paroxysms occur every 48 – 72 hours In P. malariae pyrexia may last for 8 hours or more and temperature my exceed 41 c

20. Malaria stages of the disease

21. More commonly, the patient presents with a combination of the following symptoms Fever Chills Sweats Headaches Nausea and vomiting Body aches General malaise.

22. Periodicity can be clue in Diagnosis and species relation Malaria tertiana: 48h between fevers ( P. vivax and P. ovale ) Malaria quartana: 72h between fevers ( P. malariae ) Malaria tropica: irregular high fever ( P. falciparum )

23. SEVERE COMPLICATED MALARIA Confusion, or drowsiness with extreme weakness (prostration). In addition, the following may develop: Alteration in the level of consciousness (ranging from drowsiness to deep coma) Cerebral malaria (unrousable coma not attributable to any other cause in a patient with falciparum malaria) Respiratory distress Multiple generalized convulsions (2 or more episodes within a 24 hour period) Shock (circulatory collapse, septicemia) Pulmonary edema Abnormal bleeding (Disseminated Intravascular coagulopathy) Jaundice Hemoglobinuria (black water fever) Acute renal failure - presenting as oliguria or anuria Severe anaemia (Hemoglobin < 5g/dl or Hematocrit < 15%) High fever Hypoglycemia (blood glucose level < 2.2.mmol/l) defined as the detection of P. falciparum in the peripheral blood

24. Malaria the disease

25. Why Falciparum Infections are Dangerous Can produce fatal complications, 1.Cerebral malaria 2.Malarial hyperpyrexia 3. Gastrointestinal disorders. 4. Algid malaria (SHOCK) 5 . Black water fever can lead to death

26. Pernicious Malaria Is a life threatening complication in acute falciparum malaria It is due to heavy parasitization Manifest ed with 1. Cerebral malaria – it presents with hyperpyrexia, coma and paralysis. Brain is congested 2. Algid malaria – presents with clammy skin leading to peripheral circulatory failure.

27. Cerebral Malaria Malignant malaria can affect the brain and the rest of the central nervous system. It is characterized by changes in the level of consciousness, convulsions and paralysis.

28. Cerebral Malaria Present with Hy p e r p y r e x i a Can lead to Coma Paralysis and other complications. Brain appears congested

29. Black Water Fever In malignant malaria a large number of the red blood c ell s are destroyed. Hemoglobin from the blood c ells are excreted in the urine, which therefore is dark and almost the color of cola

30. How long Malaria infection can lost in Man Without treatment P. falciparum will terminate in less than 1 year. But in P. vivax and P. ovale persist as hypnozoites after the parasites have disppeared from blood. Can prod u ce periodic relapses upto 5 years In P. malariae may last for 40 years ( Called as recrudescence X relapse )

31. LABORATORY DIAGNOSIS OF MALARIA

32. Diagnostic Tools for Human Infections with Malaria Blood film examination( Microscopy ) QBC system Rapid Diagnostic Tests (RDTs) PCR

33. Thin and Thick smear

34. Microscopy Malaria parasites can be identified by examining under the microscope a drop of the patient's blood, spread out as a "blood smear" on a microscope slide. Prior to examination, the specimen is stained (most often with the Giemsa stain ) to give to the parasites a distinctive appearance. This technique remains the gold standard for laboratory confirmation of malaria.

35. QBC system has evolved as rapid and precise method in Diagnosis The QBC Malaria method is the simplest and most sensitive method for diagnosing the following diseases. 🞑 Malaria 🞑 Babesiosis 🞑 Trypanosomiasis (Chagas disease, Sleeping Sickness) 🞑 Filariasis (Elephantiasis, Loa-Loa) 🞑 Relapsing Fever (Borreliosis)

36. Appearance of Malarial parasite in QBC system

37. Antigen Detection Methods are Rapid and Precise Antigen Detection Various test kits are available to detect antigens derived from malaria parasites and provide results in 2-15 minutes. These " Rapid Diagnostic Tests" (RDTs) . Rapid diagnostic tests (RDTs) are immunochromatographic tests based on detection of specific parasite antigens. Tests which detect histidine-rich protein 2 (HRP2) are specific for P. falciparum while those that detect parasite lactate dehydrogenase (pLDH)-OptiMAL or aldolase have the ability to differentiate between P.falciparum and non-P.falciparum malaria

38. Newer Diagnostic methods Molecular Diagnosis Parasite nucleic acids are detected using polymerase chain reaction (PCR). This technique is more accurate than microscopy. However, it is expensive, and requires a specialized laboratory (even though technical advances will likely result in field-operated PCR machines).

39. Malaria Relapses In P. vivax and P. ovale infections, patients having recovered from the first episode of illness may suffer several additional attacks ("relapses") after months or even years without symptoms. Relapses occur because P. vivax and P. ovale have dormant liver stage parasites (" hypnozoites ") that may reactivate.

40. Prevention Avoid mosquito bites: Wearing long sleeves, trousers. Insecticide Treated Bednets Repellent creams or sprays.