MALARIA- PowerPoint presentation pptx part 1

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1. MALARIA-I Dr Dayavanti (Microbiology)

2. History:- “Mal” means bad and “aria” means air -“disease is spread by air pollution through stagnant water and marshy lands” Alphonse Laveran (1880) discovered the causative agent Plasmodium , in the RBC of a patient in Algeria. Sir Ronald Ross (1897) - described the sexual cycle of the parasite in female Anopheles mosquito in Secunderabad , India.

3. Agent:- Human infection is mainly caused by five species such as: P. vivax causes benign tertian malaria (periodicity of fever is once in 48 hours) P. falciparum causes malignant tertian malaria (severe malaria, periodicity of fever is once in 48 hours) P. malariae causes benign quartan malaria (periodicity of fever is once in 72 hours) P. ovale causes ovale tertian malaria (periodicity of fever is once in 48 hours) P. knowlesi causes quotidian or simian malaria (fever periodicity is once in 24 hours, i.e. recurs every day). It is a parasite of monkey but can also infect humans and many cases affecting man were recently reported from Asia.

4. Mode of Transmission and Infective Form Man acquires infection by the bite of female Anopheles mosquito Rarely, by blood transfusion or transplacental transmission

5. Life Cycle:- Host: Plasmodium completes its life cycle in two hosts: Definitive host - Female Anopheles mosquito(sexual cycle) Intermediate host – Man (asexual cycle)

6. Life Cycle – Human cycle Pre-erythrocytic (Hepatic) Stage Erythrocytic schizogony Gametogony

7. Life Cycle – Mosquito cycle A female Anopheles mosquito during the blood meal, takes both asexual and the sexual forms. The asexual forms get digested whereas the sexual forms, i.e. the gametocytes undergo further development.

8. Relapse and recrudescence in malaria

9. Differences between malaria parasites

10. Pathogenesis and Clinical Feature – Benign malaria Benign malaria is milder in nature. Caused by all four species Characterized by a triad of febrile paroxysm, anemia and splenomegaly.

11. Pathogenesis and Clinical Feature - Benign malaria (Cont..) Febrile Paroxysm: Fever comes intermittently depending on the species. Occurs every fourth day (72 hour cycle for P. malariae ) and every third day (48 hour cycle for other three species). Paroxysm corresponds to the release of the successive broods of merozoites into the bloodstream, at the end of RBC cycle.

12. Pathogenesis and Clinical Feature - Benign malaria (Cont..) Febrile Paroxysm (Cont..): Each paroxysm of fever is comprised of three stages. 1. Cold stage (15mins to 1hour) 2. Hot stage 3. Sweating stage (2-4hrs)

13. Pathogenesis and Clinical Feature - Benign malaria (Cont..) Anemia: Patient develops normocytic normochromic anemia - attributed to various factors. Parasite induced RBC destruction—Lysis of RBC due to release of merozoites Splenic removal of both infected RBC and uninfected RBC coated with immune complexes Bone marrow suppression leading to decreased RBC production.

14. Pathogenesis and Clinical Feature - Benign malaria (Cont..) Splenomegaly : After a few weeks of febrile paroxysms, spleen gets enlarged and becomes palpable. Splenomegaly is due to massive proliferation of macrophages that engulf parasitized and nonparasitized coated RBCs.

15. Pathogenesis and Clinical Feature - Falciparum Malaria ( Malignant Tertian Malaria) An important feature of the pathogenesis of P. falciparum - ability to sequester (holding back) the parasites in the blood vessels of deep visceral organs like brain, kidney, etc. This leads to blockage of vessels, congestion and hypoxia of internal organs.

16. Complications - Falciparum Malaria Cerebral malaria Pernicious anemia Black water fever Algid malaria Septicemic malaria Pulmonary edema and adult respiratory distress syndrome Hypoglycemia Renal failure Bleeding/disseminated intravascular coagulation Severe jaundice Severe normochromic, normocytic anemia Acidosis

17. Immunity against Malaria Both innate and acquired immunity contribute to the resistance against malaria.

18. Innate Immunity Refers to inherent mechanisms of host resistance against malaria parasite. This depends upon various factors: Age of RBCs Nature of hemoglobin Hereditary ovalocytosis G6PD deficiency Duffy negative red blood cells Nutritional status

19. Acquired Immunity Both cellular and humoral immunity contribute to the resistance against malaria. Premunition

20. Epidemiology of Malaria Malaria is the most lethal parasitic disease of humans. Transmitted in 108 countries containing 3 billion people. In 2018, 228 million cases of malaria with about 4 lakh deaths occurred worldwide. Africa affected the worst (93%), followed by South-East Asia (3.4%). Incidence rate - About 57 cases per 1000 population at risk. P. falciparum - most common species worldwide - accounting for 99.7% of malaria cases in African region.

21. According to National Vector Borne Disease Control Programme (NVBDCP), 3.3 lakh malaria cases were reported from India in 2019, with 73 deaths. Over the last decade, Eastern Indian states - Odisha, Chhattisgarh and Jharkhand - maximum malaria cases - P. falciparum - predominant species In 2018 and 2019 - Uttar Pradesh - highest malaria burden in India - majority of cases were due to P. vivax . P. vivax - most common species in India (>50%), followed by P. falciparum (46%). P. malariae infections - <1% and are reported from - Karnataka, Chhattisgarh, Odisha, West Bengal, Madhya Pradesh, Tamil Nadu, Kerala and Assam. P. ovale - confined to tropical Africa. Only few cases are reported from India - Odisha, Chhattisgarh, Delhi, Assam, Gujarat and Kolkata.

22. Malaria Elimination in India Malaria control in India has been operated through NVBDCP since 2006. WHO has initiated The Global Technical Strategy for Malaria (2016–2030) - aims at elimination of malaria by year 2030. Till date 38 countries have already achieved the elimination status from WHO. In line with WHO, NVBDCP India has launched National Framework for Malaria Elimination (NFME) in 2016 with vision of malaria elimination by 2030. All states/ UTs of India are stratified into four categories based on annual parasite incidence (API).

23. World Malaria Day: Every year, 25 th April is being celebrated as “World Malaria Day” Antimalarial month is celebrated every June.

24. Laboratory diagnosis of malaria Microscopic tests: Peripheral blood smear - gold standard Thick smear - more sensitive Thin smear

25. Microscopic tests (Cont..): P. falciparum - ring forms (multiple ring form, accole form, headphone shaped ring forms), banana shaped gametocyte P. malariae - band forms P. ovale - enlarged fimbriated oval RBC with ring forms

26. Microscopic tests (Cont..): Fluorescence microscopy Quantitative buffy coat examination —parasitized RBCs appear as brilliant green dots

27. Non-microscopic tests: Antigen detection tests (RDTs)- detect pan malarial Ag (LDH, aldolase), falciparum specific Ag (HRP-II) Culture - RPMI 1640 medium Molecular diagnosis - PCR targeting 18S rDNA

28. Peripheral Blood Smear It is the simple and gold standard confirmatory test Specimen - Peripheral blood is collected from ear lobe or by finger prick or great toe (in infants). Time for taking blood: Collected few hours after the height of the paroxysm of fever and before taking antimalarial drugs.

29. Peripheral Blood Smear (Cont..) Frequency: Smears should be examined at least twice daily until parasites are detected. Types of peripheral blood smear- (1) thin and (2) thick smears. Smears are stained with one of the Romanowsky’s stains such as Leishman’s, Giemsa and Field’s, Wright’s or JSB stain Thin smear has to be screened first . It is screened near the feathery tail end

30. Thin blood smear showing different forms of Plasmodium vivax A. Ring form; B. Amoeboid form; C. Schizont; D. Male gametocyte; E. Female gametocyte

31. Thin blood smear showing different forms of Plasmodium falciparum A . P. falciparum ring forms such as multiple rings (blue arrow), accole form (red arrow) and head phone-shaped ring form (black arrow); B . Female gametocyte of P. falciparum; C . Male gametocyte of P. falciparum; D . Band form of P. malariae ; E . Ring form of P. ovale

32. Quantitative Buffy Coat Examination Blood (60 µL) is collected in a capillary tube coated internally with acridine orange. Capillary tube is centrifuged - causes separation of components of blood according to their densities, forming discrete layers as RBCs, WBCs, lymphocytes and platelets Examination of capillary tube at the buffy coat region under ultraviolet (UV) light source

33. Antigen Detection by Rapid Diagnostic Tests 1) Parasite lactate dehydrogenase ( pLDH ): Currently available test kits can differentiate pan malarial pLDH common to all species and pLDH specific to P. falciparum 2) Parasite aldolase : Produced by all Plasmodium species. 3) Plasmodium falciparum specific histidine rich protein-2 ( Pf -HRP-II):

34. Culture Culture techniques are mainly used for preparation of malaria antigens, not for diagnosis. Trager and Jensen method using RPMI 1640 medium (Roswell Park Memorial Institute) - most widely used technique for culture of malaria parasite.

35. Antimalarial drugs

36. Treatment of Vivax Malaria

37. Treatment of Falciparum Malaria

38. Prophylaxis against Malaria Chemoprophylaxis Vector control strategies Vaccine prophylaxis.

39. For short-term chemoprophylaxis (<6 weeks): Doxycycline is recommended, at a dose of 100 mg daily in adults and 1.5 mg/kg for children. The drug should be started 2 days before travel and continued for 4 weeks after leaving the malaria endemic area. Long-term chemoprophylaxis (>6 weeks): Mefloquine is recommended at a dose of 5 mg/kg weekly and administered two weeks before, during and four weeks after leaving the area.

40. Vector Control Strategies Anti-adult measures Residual insecticide spraying: Dichloro diphenyltrichloroethane (DDT), malathion and fenitrothion is highly effective against adult mosquito Space application of pesticide in the form of fog Individual protection: by using insecticide treated bed nets, repellents and protective clothing.

41. Anti-larval measures Larvicide: Use of mineral oil or Paris green to kill mosquito larvae and pupae Source reduction (mosquito breeding sites): Includes environmental sanitation, water management and improvement of the drainage system. Biological larvicide: Gambusia affinis (fish) and Bacillus thuringiensis (bacteria) can be used to kill the mosquito larva.

42. Vaccination for Malaria Pre-erythrocytic vaccine target sporozoites and liver schizonts . Erythrocytic vaccine target merozoites, blood schizonts Sexual stage vaccine target gametocytes RTS, S/AS01 It is the only vaccine candidate that has successfully completed phase III trial.

43. THANK YOU….