Malaria (มาลาเรีย) Assoc. Prof. Pradya Somboon, Ph.D. 1

Objectives 1.Morphology and Life cycle 2.Pathophysiology 3.Epidemiology and control 2

Human malarial parasites Plasmodium malariae (Quartan malaria) P. vivax (Benign tertian malaria) P. falciparum (Malignant tertian malaria) P. ovale (Ovale tertian malaria) Primate malaria parasites infecting man e.g. Plasmodium knowlesi Thai local names: ไข้จับสั่น ไข้ป่า ไข้ป้าง ไข้ร้อน เย็น ไข้ดอกสัก 3

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Anopheles ยุงก้นปล่อง Human Sporogony Schizogony (Asexual phase) (Sexual phase) 5

Life cycle of malaria parasites 6

Tissue schizont and hypnozoite vivax, ovale hypnozoite 7

Early trophozoite (ring form) Infect normal sized or small rbc: P. malariae Infect large (young) rbc: P. vivax, P. ovale Infect all aged rbc: P. falciparum Pm, PfPv, Po 8

Growing trophozoite PfPvPo Pm, bandPm, compactPm, irregular 9

Growing trophozoites Hb haemozoin (malarial pigment) Stippling: Schuffner’s dots: Pv, Po Maurer’s clefts: Pf Ziemann’s dots: Pm 10

Immature schizonts Pv Po Pm 11

PmPv Po Pf Mature schizonts merozoites

C o 37 Febrile paroxysm P. vivax, P. ovale Day 13

Gametocytes Pm Pv, Po Pf male female male female male female 14

P. falciparum ring form gametocytes male female Microgametocyte = male Macrogametocyte = female 15

Sporogony in mosquito midgut microgametocyte (male) 6-8 microgametes macrogamete (female) exflagellation + Zygote Ookinete Oocyst Sporozoites macrogametocyte (female) 16

Mosquito midgut with malarial oocysts 17

Sporozoites in salivary glands 18

Malarial infections 1. Bitten by an infected anopheline 2. Blood transfusion 3. Congenital 19

Course of infection Prepatent period (days) Incubation period (days) av.(range) Patent period (yr) av./max Pv (12-17+) 2/8 Po (16-18+) 1/5 Pf9-1612(9-14) 1/4 Pm (18-90) 4/53 20

Infection DEATH Infection RECRUDESCENCE Infection Treatment RECRUDESCENCE (R1 RESISTANCE) Re-infection RELAPSE (hypnozoite) Possible outcome of malaria infections PF All PF All PV, PO Parasite density Time (Blood stages) 21

Vivax and ovale malaria (Benign tertian malaria) Non-specific symptoms 2-3 days followed by febrile paroxysm (malaria paroxysm) every other day Cold stage 5-60 min Hot stage 2-6 hr Sweating stage 2-4 hr Clinical aspects malaria paroxysm 22

C o 37 Febrile paroxysm P. vivax, P. ovale Day 23

Malariae malaria (Quartan malaria) Febrile paroxysm every 72 hr. Nephrotic syndrome - the presence of nephrotic-range proteinuria, edema, hyperlipidemia, and hypoalbuminemia 24

Days C o 37 Febrile paroxysm P. malariae (P. knowlesi 24 hr.) 25

non-specific symptoms fever (every day or every other day) chill, headache, influenza-like, pains of limbs and back, nausea etc. Falciparum malaria (Malignant tertian malaria) 26

Complications of severe falciparum malaria Cerebral malaria Anaemia Renal failure Hypoglycaemia etc. caused by blocking of capillaries 27

non-specific symptoms fever (every day or every other day) chill, headache, influenza-like, pains of limbs and back, nausea etc. Falciparum malaria (Malignant tertian malaria) 28

Malaria Pathology - rupture of infected and uninfected rbc - release of toxins, malarial pigment - packing capillaries (cytoadherence) in brain, kidney, etc.(only Pf) - enlarged spleen - black water fever 29

Liver 30

Kidney 31

Malaria immunity Natural immunity Animal malarias Human P. vivax Duffy bl. gr. Neg. P. falciparum HbS P. falciparum G-6-PD def. Acquired immunity Active: experience infections Passive: congenital Imm. 32

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2 P. knowlesi distribution 36

Crab-eating macaque (ลิงแสม) Pig-tailed macaque (ลิงกัง) 38

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Malaria control 1. Blocking man-vector contact bednets, repellant 2. Vector control residual spray, insecticide-treated bednets, environmental control 3. Treatment of malaria cases active and passive case detections 4. Drug prophylaxis 41

Chemotherapy 1. Prophylactic use – not recommended 2. Therapeutic use -blood schizontocides Pf - mefloquine, quinine, artesunate, artemether Pv, Po, Pm - chloroquine - tissue schizontocides primaquine (Pv, Po) 3. Prevent transmission primaquine (Pf gametocyte) 42

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Laboratory diagnosis for malaria Thick blood film Thin blood film Giemsa stain 44

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Giemsa stained thin blood film 1. Infected rbc large with Schuffner’s dots ……….…. Pv or Po …....2 Infected rbc not large, no stippling seen …………. Pf or Pm … Active amoeboid form common, mature sch. has ~16 merozoites …… Pv Non-active amoeboid form, oval shaped, mature sch. has 6-12 merozoites ……..Po 3. Only ring form and/or banana-shaped gametocyte present ……………………..Pf Several forms with pigments scattering in cytoplasm ………………...Pm 46