MALARIA

1. MALARIA Assignment on BCH 514 Clinical Biochemistry Submitted by Selma Abdul Samad BCH-10-05-02 S3 MSc.Biochemistry

2. What is Malaria ?? • An infectious tropical Disease caused by the parasite Plasmodium sp. in humans • The name malaria derived from the Italian mal’ariaor bad air • Fifth cause of death from infectious diseases worldwide (after respiratory infections, HIV/AIDS, diarrhoeal diseases, and tuberculosis) and the second in Africa, after HIV/AIDS • It is a disease that can be treated in just 48 hours, yet it can cause fatal complications if the diagnosis and treatment are delayed.

3. Geographical Distribution • #1 priority tropical disease of WHO • Prevalent in 108 countries of the tropical and semitropical world (home to half of the world) • Every year, malaria is reported to cause more than 250-660 million infections and more than a million deaths (mostly among African children) • There has been a sharp decline in the incidence of malaria in South-East Asia since 1977 reflecting a rapid fall in India and Sri Lanka but . there has been a slow increase in South and Central America.

4. Geographical Distribution

6. In India .. • Orissa, Chhattisgarh, West Bengal, Jharkhand and Karnataka contribute the most number of cases of malaria in India

7. HISTORY OF MALARIA • One of the oldest diseases known to mankind • Wars , kings , dynasties etc influenced • Malaria was linked with poisonous vapours of swamps or stagnant water on the ground since time immemorial. • The word was introduced to English by Horace Walpole, who wrote in 1740 about a “horrid thing called mal’aria, that comes to Rome every summer and kills one.” The term malaria, without the apostrophe, evolved into the name of the disease only in the 20th . century.

8. Man and Malaria seem to have evolved together • It is believed that most, if not all, of today's populations of human malaria may have had their origin in West Africa (P. falciparum) and West and Central Africa (P. vivax) on the basis of the presence of homozygous alleles for hemoglobin C and RBC Duffy negativity that confer protection against P. falciparum and P. vivax respectively

9. Different studies have suggested that P. falciparum malaria probably jumped from great apes to man, probably by a single host transfer by vector mosquitoes • P. malariae, P. ovale, and P. vivax diverged over 100 million years ago along the lineage of the mammalian malaria parasites • P. ovale is the the sole known surviving representative of its line and causes infection only in humans

10. Famous victims of malaria • Alexander the Great is believed to have died of malaria in 323 BC, on the route to India beyond Mesopotamia • George Washington, (1st President of US, 1789-1797): Developed his first bout with malaria in Virginia in 1749 at age 17. He had periodic attacks, recorded in 1752, 1761, 1784, and 1798. • Abraham Lincoln (16th President, 1861-1865) had periodic bouts of malaria when growing up • John F. Kennedy (35th President, 1961-1963) acquired malaria during World War II, about 1943 • Mother Teresa was hospitalized with malaria in 1993 • , ……………….and many many others………………..

11. Scientific Discoveries… • Hippocrates was probably the the first malariologist • The Hippocratic corpus was the first document to mention • about splenic change in malaria and also it attributed malaria • to ingestion of stagnant water

12. Time Line For Scientific Discoveries • Ancient Times - Early man attributed the fevers to evil spirits, angered deities, demons, or the black magic of sorcerers • Severel thousand years ago - Babylonian cuneiform script attributes malaria to a god, pictured as a mosquito-like insect • 800 BC - Indian sage Dhanvantari wrote that bites of mosquitoes could causes diseases, fever, shivering etc. • 400 BC - Hippocrates described the various malaria fevers of man; distinguished the intermittent malarial fever from the other continuous fevers; noted the daily, every-other-day, and every-third-day temperature rise; mentioned about splenic change in malaria; attributed malaria to ingestion of stagnant water; also related the fever to the time of the year and to where the patients lived

13. Several theories and hypotheses came for years • It was finally in 1884 that Plasmodium was discovered by Russian Scientists and their link with malaria was confirmed by Louis Pasteur. • In 1897 Ronald Ross demonstrated oocysts in the gut of anopheline mosquito at Secunderabad, India, proving that mosquito was the vector for malaria

14. Nobel Prizes for Malaria Related Research • Ronald Ross, 1902: "For his work on malaria, by which he has shown how it enters the organism and thereby has laid the foundation for successful research on this disease and methods of combating it". Ronald Ross demonstrated the oocyst of malarial parasite in the gut wall of a mosquito on August 20, 1897 in Secunderabad, India. • Alphonse Laveran, 1907: "In recognition of his work on the role played by protozoa in causing diseases". Laveran was the first to notice parasites in the blood of a patient suffering from malaria on November 6, 1880 at Constantine, Algeria.

15. Julius Wagner-Jauregg, 1927: "For his discovery of the therapeutic value of malaria inoculation in the treatment of dementia paralytica". • Paul Hermann Müller, 1948: "For his discovery of the high efficiency of DDT as a contact poison against several arthropods".

16. Etiology • 5 species of malaria parasites that infect man identified • Plasmodium vivax (vivax malaria, benign tertian malaria) • Plasmodium ovale (ovale malaria, ovale tertian malaria) • Plasmodium malariae (quartan malaria) • Plasmodium falciparum (falciparum malaria, malignant tertian malaria, pernicious malaria, subtertian malaria) • Plasmodium knowlesi

17. The Malaria Parasites • Protozoan parasites called Plasmodia • Phylum: Protozoa • Class: Sporozoa • Genus: Plasmodia • Species : several species, 5 known to affect man

20. INFECTION • TRANSMISSION • Principal mode of spread of malaria is by the bites of female Anopheles mosquito • Of more than 480 species ofAnopheles, only about 50 species transmit malaria • The habits of most of the anopheline mosquitoes have been characterised as anthropophilic (prefer human blood meal), endophagic (bite indoors), and nocturnal (bite at night) with peak biting at midnight, between 11 pm and 2 am.

21. The blood meal from a vertebrate host is essential for the female mosquitoes to nourish their eggs. • The mosquitoes find their host by seeking visual, thermal, and olfactory stimuli and of these, carbon dioxide, lactic acid, skin temperature, and moisture are more important mosquito attractants • When a mosquito bites an infected individual, it sucks the gametocytes, the sexual forms of the parasite, along with blood. These gametocytes continue the sexual phase of the cycle within the mosquito gut and the sporozoites that develop then fill the salivary glands of the infested mosquito. When this female mosquito bites another man for a blood meal, the sporozoites are inoculated into the blood stream of the fresh victim, thus spreading the infection.

22. Anopheles Mosquito • Malaria is transmitted from man to man by the female anopheles mosquito • Nearly 45 species of the mosquito have been found in India • How does a mosquito bite? Anopheles Mosquito

23. Other modes of transmission • Mother to the growing fetus(Congenital malaria) - transplacentally or during labor • Transfusion Malaria: transmitted by transfusion of blood from infected donors. • Needle stick injury: accidentally among health care or due to needle sharing among drug addicts

24. LIFE CYCLE • The malaria parasite has a complex, multistage life cycle occurring within two living beings, the vector mosquitoes and the vertebrate hosts. • Consits of two phases • Sexual phase ( sporogony) – in female anopheles mosquito • Asexual phase ( schizogony) – in man

25.  The parasite passes through several stages of development such as the • sporozoites (Gr. Sporos = seeds; the infectious form injected by the mosquito) • merozoites (Gr. Meros = piece; the stage invading the erythrocytes) • trophozoites (Gr. Trophes = nourishment; the form multiplying in erythrocytes) and • gametocytes (sexual stages) • all these stages have their own unique shapes and structures and protein complements. • The surface proteins and metabolic pathways keep changing during these different stages, that help the parasite to evade the immune clearance, while also creating problems for the development of drugs and vaccines

26. Sporogony Within the Mosquitoes • Mosquitoes are the definitive hosts for the malaria parasites, wherein the sexual phase(sporogony) of the parasite's life cycle occurs • Results in the development of innumerable infecting forms of the parasite within the mosquito that induce disease in the human host following their injection with the mosquito bite • Infected individual  mosquito draws blood  the male and female gametocytes of the parasite find their way into the gut of the mosquito • Female forms macrogametes ; Males form microgamete

27. The male and female gametes fuse in the mosquito gut to form zygotes, which subsequently develop into actively moving ookinetes that burrow into the mosquito midgut wall to develop into oocysts. • Growth and division of each oocyst produces thousands of active haploid forms called sporozoites. • After the sporogonic phase of 8–15 days, the oocyst bursts and releases sporozoites into the body cavity of the mosquito, from where they travel to and invade the mosquito salivary glands.

28. When the mosquito thus loaded with sporozoites takes another blood meal, the sporozoites get injected from its salivary glands into the human bloodstream, causing malaria infection in the human host. • It has been found that the infected mosquito and the parasite mutually benefit each other and thereby promote transmission of the infection. The Plasmodium-infected mosquitoes have a better survival and show an increased rate of blood-feeding, particularly from an infected host. • The duration of the cycle in the mosquito is known as the external incubation period and varies from 8-10 days (28`C) to 16 days (20`C)

29. Malaria oocysts on stomach of mosquito

30. Schizogony in the Human Host • Man is the intermediate host for malaria, wherein the asexual phase of the life cycle occurs. • The sporozoites inoculated by the infested mosquito initiate this phase of the cycle from the liver, and the latter part continues within the red blood cells, which results in the various clinical manifestations of the disease. • Pre-erythrocytic Phase - Schizogony in the Liver: • With the mosquito bite, tens to a few hundred invasive sporozoites are introduced into the skin. • Following the intradermal deposition, some sporozoites are destroyed by the local macrophages, some enter the lymphatics, and some others find a blood vessel.

31. The sporozoites that enter a lymphatic vessel reach the draining lymph node wherein some of the sporozoites partially develop into exoerythrocytic stages and may also prime the T cells to mount a protective immune response • The sporozoites that find a blood vessel reach the liver within a few hours •  The sporozoites then negotiate through the liver sinusoids, and migrate into a few hepatocytes, and then multiply and grow within parasitophorous vacuoles. • Each sporozoite develop into a schizont containing 10,000–30,000 merozoites (or more in case of P. falciparum. • The growth and development of the parasite in the liver cells is facilitated by a afavorable environment created by the Thecircumsporozoite protein of the parasite.

32. The entire pre-erythrocytic phase lasts about 5–16 days depending on the parasite species: • on an average 5-6 days for P. falciparum, • 8 days forP. vivax, • 9 days for P. ovale, • 13 days for P. malariaeand • 8-9 days for P. knowlesi. • The pre-erythrocytic phase remains a “silent” phase, with little pathology and no symptoms, as only a few hepatocytes are affected. This phase is also a single cycle, unlike the next, erythrocytic stage, which occurs repeatedly.

33. The merozoites that develop within the hepatocyte are contained inside host cell-derived vesicles called merosomes that exit the liver intact, thereby protecting the merozoites from phagocytosis by Kupffer cells. • These merozoites are eventually released into the blood stream at the lung capillaries and initiate the blood stage of infection thereon. • In P. vivax and P. ovale malaria, some of the sporozoites may remain dormant for months within the liver. Termed as hypnozoites, these forms develop into schizonts after some latent period, usually of a few weeks to months.

34. ErythrocyticSchizogony - Centre Stage in Red Cells • Red blood cells are the 'centre stage' for the asexual development of the malaria parasite. • Within the red cells, repeated cycles of parasitic development occur with precise periodicity, and at the end of each cycle, hundreds of fresh daughter parasites are released that invade more number of red cells. • The merozoites released from the liver recognize, attach, and enter the red blood cells (RBCs) by multiple receptor–ligand interactions in as little as 60 seconds. This quick disappearance from the circulation into the red cells minimises the exposure of the antigens on the surface of the parasite, thereby . protecting these parasite forms from the host immune response.

35. The invasion of the merozoites into the red cells is facilitated by molecular interactions between distinct ligands on the merozoite and host receptors on the erythrocyte membrane. Glycophorin, the major erythrocytic glycoprotein is involved in merozoite invasion. • The more virulent P. falciparum uses several different receptor families and alternate invasion pathways that are highly redundant and hence can invade any red cell while others like P.vivax can invade using one type of receptor.

36. The process of attachment, invasion, and establishment of the merozoite into the red cell is made possible by the specialized apical secretory organelles of the merozoite, called the micronemes, rhoptries, and dense granules. • The initial interaction between the parasite and the red cell stimulates a rapid “wave” of deformation across the red cell membrane, leading to the formation of a stable parasite–host cell junction. • Following this, the parasite pushes its way through the erythrocyte bilayer with the help of the actin–myosin motor, proteins of the thrombospondin-related anonymous protein family (TRAP) and aldolase, and creates a parasitophorous vacuole to seal itself from the host-cell cytoplasm, thus creating a hospitable environment for its development within the red cell. • At this stage, the parasite appears as an intracellular “ring”.

38. The ring forms grow in size to trophozoites. Meanwhile, they utiliseHb . ie., the amino acids are utilised for protein bioshynthesis and the toxic heme is detoxified by heme polymerase and sequestered as hemozoin (malaria pigment) • The parasite depends on anaerobic glycolysis for energy • The trophozoite multiplies by schizogony dividing into a number of small merozoites varying with the species to form a mature schizont. • The erythrocytic phase is called schizogonic periodicity • At the end of the cycle,themerozoites are released by rupture of the red cell membrane and enter new red cells, particularly young red cells.

39. The erythrocytic cycle occurs every • 24 hours in case of P. knowlesi, • 48 h in cases of P. falciparum, P. vivax and P. ovale and • 72 h in case of P. malariae.  • During each cycle, each merozoite grows and divides within the vacuole into 8–32 (average 10) fresh merozoites, through the stages of ring, trophozoite, and schizont.

40. Gametogony : • A small proportion of asexual parasites do not undergo schizogony but differentiate into the sexual stage gametocytes. • These male or female gametocytes are extracellular and nonpathogenic and help in transmission of the infection to others through the female anopheline mosquitoes, wherein they continue the sexual phase of the parasite's life cycle. • Gametocytes of P. vivax develop soon after the release of merozoites from the liver, whereas in case of P. falciparum, the gametocytes develop much later with peak densities of the sexual stages typically occurring 1 week after peak asexual stage densities.

44. PATHOLOGY • The most pronounced changes related to malaria involve the blood and the blood-forming system, the spleen and the liver. • Secondary changes can occur in all the other major organs, depending on the type and severity of the infection. • The pathological changes are more profound and severe in case of P. falciparummalaria. Severe malaria is a complex multisystem disorder with many similarities to sepsis syndromes.

45. RBC rupture ; cytoadherence and sequestration • Anemia • Thrombocytopenia ; Clotting defects • Elevated ESR • Bone marrow may show evidence of dyserythropoeisis, iron sequestration and erythrophagocytosis in the acute phase of falciparum malaria. • Splenomegaly ; Splenic rupture • Malarial hepatitis ; Hepatomegaly • cardiovascular function abnormalities

46. GI irritation, ischemia, ulcers , necrosis • Nephritis ; albuminuria ; kidney failure ; edema • CNS manifestations ( in P.falciparum) • All pathological manifestations increased and severe in case of falciparum malaria

47. CLINICAL FEATURES • All the clinical features of malaria are caused by the erythrocyticschizogony in the blood • Typical features: • It includes three stages viz. Cold stage, Hot stage and Sweating stage • The febrile episode starts with shaking chills, usually at mid-day between 11 a.m. to 12 noon, and this lasts from 15 minutes to 1 hour (the cold stage) • Followed by high grade fever, even reaching above 1060 F, which lasts 2 to 6 hours (the hot stage). • This is followed by profuse sweating and the fever gradually subsides over 2-4 hours. These typical features are seen after the infection gets established for about a week.

48. In vivax malaria, this typical pattern of fever recurs once every 48 hours and this is called as Benign Tertian malaria. • Similar pattern may be seen in ovale malaria too (Ovale tertian malaria). • In falciparum infection (Malignant tertianmalaria), this pattern may not be seen often and the paroxysms tend to be more frequent (Sub-tertian). • In P. malariae infection, the relapses occur once every 72 hours and it is called Quartan malaria.

49. Atypical features: In an endemic area, malaria often presents with atypical manifestations • Atypical fever • Headache • Body ache, back ache and joint pains • Dizziness, vertigo • Altered behaviour, acute psychosis • Altered sensorium • Convulsions, coma • Cough • Breathlessness • Chest pain

50. Acute abdomen • Weakness • Vomiting and diarrhoea • Jaundice • Pallor • Puffiness of lids • Secondary infections • Hepatosplenomegaly • Combinations of the above