Malaria and Filariasis

What is the pre patent period

Time from inoculation of sporozoite until parasites are detected by microscopy of blood

What is incubation period

Time from inoculation of sporozoits until a person develops clinical signs

What is relapse

New brood of parasites from hypnozoites in liver

What is recrudesence

Undetectable blood stage infection caused by drug resistance, unusual pharmacokinetics or incomplete dose

What is reinfection

Caused by new exposure

What is unstable malaria

Seasonal transmission

Plasmodium falciparum incubation period

9-14 day

Plasmodium vivax incubation period

12-17 day

Plasmodium malariae incubation period

18-40 day

Plasmodium ovale incubation period

16-18 day

Plasmodium knowlesi incubation period

9-12 day

Which plasmodium species has the shortest intra-erythrocytic cycle

24 hours; P knowlesi

How is P. knowlesi diagnosed

PCR ONLY

Malaria life cycle

Schizogony: Sporozoite replicate in hepatocyte → Merozoite enter RBC (symptom stage) → Ring stage (early trophozoite) → trophozoite → Schizont → Schizont break into merozoite → spread into blood

How does malaria cause fever

Malaria toxin in blood → Burst of TNF alpha by activated M → Fever = overproduction of TNF a

TNF a toxicity also causes what symptoms

Nausea, muscle pain, headache, loss of appetite

How does malaria affect liver

Sporozoite invade hepatocyte → Kupffer cells accumulate hemozoin pigment → Reduction of phagocytic ability → Kupffer loss of function

Malaria in the spleen

Anemia from destroyed RBC → Splenomegaly from increased RBC formation

Malaria in kidney

Acute renal failure; Hb and breakdown products accumulate faster than liver clearance; hypovolemia; Blackwater fever

What is blackwater fever

Dark urine with severe fever, jaundice and vomiting

What counts as malaria infection

Hyperparasitemia; >2% for low transmission area and >5% in high transmission area

P falciparum characteristic (clinical disease, intra-erythrocytic cycle, sequestration, parasitemia)

Severe; 43-52 hrs; sequestration; high and commonly infect cells

P vivax characteristic (intra-erythrocytic cycle, hypnozoite stage, infected RBC, )

48 hrs; hypnozoite stage; infects reticulocytes

P malariae intra-erythrocytic cycle

72 hrs

P ovale characteristic (intra-erythrocytic cycle, hypnozoite stage)

48 hrs; hypnozoite stage

Which plasmodium have hypnozoite stages

P vivax and P ovale

What is P falciparum

Main cause of mortality; cerebral malaria; recrudescence, high parasitemia, only RINGS and GAMTETOCYTES

P falciparum ring stage

P falciparum gametocyte

(left)

P falciparum rings with Maurer’s cleft (dot)

CNS malaria

Cerebral from P falciparum and Mild cerebral from other plasmodium species

What is P vivax

Only colonize duffy blood group ag; Latent = hypnozoite stage; normal to enlarged RBC; Schuffner’s dots

P vivax ameboid trophozoite

Dots are schuffner’s dots

What is P ovale

Hypnozoite in liver = long lasting latent infection; ONLY in reticulocytes; low parasitemia; James’ dots

P ovale ring form

Trophozoite with James’ dot

What is P malariae

Latent infection; low parasitemia; merozoites invade OLDER RBC

P malariae ring form

P malariae with ziemann’s dot

P malariae schizont

P malariae trophozoite

What is P knowlesi

Zoonotic species; Malaysia and Indonesia; Fatal infection; invade RBC with duffy group

Malaria in pregnancy

hypoglycemia and pulmonary edema; parasitemia peaks in second trimester

What mosquito species carry filariasis causing parasite

Culex, Aedes, Anopheles, Mansonia

What are two important causes of lymphatic filariasis

Wucheria bancrofti, Brugia malayi

What is lymphatic filariasis

Cause lymphatic damage and dysfunction → Lead to elephantiasis and hydroceles

What is the main cause of elephantiasis and hydroceles

W. bancrofti

What is acute filarial lymphangitis

Inflammation of lymphatic vessel

What is acute dermato-lymphangioadenitis

Bacterial infection of small collecting lymphatic vessels