Malaria

Sporogenic cycle of Malaria

1. Mosquito ingest infected blood 2. male and female gametocytes fuse to form diploid zygote 3. Zygote transitions to an oocyst and implants in gut wall 4. oocyst subdivides by meiosis into ~8000 sporozoites 5. sporozoites migrate into salivary gland 6. infection transmitted to new host upon feeding

What is the life cycle of malaria parasite

1. Sporogenic cycle 2. Pro-erythrocytic cycle 3. Erythrocycic cycle

Erythrocyte cycle of malaria

AKA blood phase (all forms of malaria infect RBCs) 1. RBCs infected 2. Malaria multiplies to high numbers 3. RBCs ruptured due to high numbers releasing additional merozoites into the blood stream 4. Merozoites infect healthy RBCs and some become haploid gametocytes 5. mosquito bites infected individual, taking up haploid gametocytes and process starts over.

Pro-erythrocyte cycle of malaria

AKA liver stage 1. Mosquito bites human and injects salivary anti-coagulant containing sporozoites 2. Sporozoites rapidly invade liver cells forming HEPATIC SCHIZONTS 3. sporozoites replicate asexually 4. schizont ruptures releasing MEROZOITES with invade RBCs (inhibition of pro-erythrocyte stage is goal to vaccine)

What type of infection is malaria?

Blood borne protozoa infection

Clinical presentation of Malaria in the first few days

Can present with non-specific prodrome lasting several days Symptoms: -Headache -Malaise -Cough -Myalgia -Low fever

How does P. falciparum change RBCs morphologically?

Cellular knobs on RBCs promote agglutination of RBCs Cytoadherence is promoter of cerebral malaria Leads to intracapillary sequestration of infected RBCs to endothelial cells within organs

What is the vector of malaria?

Female anopheles mosquitoes Mosquito ingests human RBCS with heploid gametocytes that fuse to form diploid ocycsts. they then divide and multiply in the mosquito Sporogenic cycle begins and ends within mosquito

Clinical presentation of Malaria after 3-7 days

Fever, shaking , chills, and sweats Initial period of shivering and chills lasts 1-2 hours -High fever for 2-6 hours -excessive sweating causes patient temp to drop to normal This cycle repeats every 48 hours for P. falciparum

Why is plasmodium falciparum so severe?

Infects RBCs of all ages (<80% of cells) Creates KNOBS on infected RBCs witch stick to endothelial cells -this causes capillary obstruction, tissue hypoxia, and tissue necrosis It has the shortes incubation period of all plasmodium spp. Has most rapid erythrocytic cycle

How is malaria controlled?

Insecticide treated bed nets Indoor residual spraying walls within homes Vector control- control/eradication of mosquito pop

Clinical presentation for severe disease

Jaundice -> liver failure Shock-> multiple organ failure Respiratory failure Coma 20% fatality rate in adults and 15% in children WITH THERAPY

What organism caused malaria?

Plasmodium species There are five species of plasmodium associated with this disease P. falciparum is the most virulent human malarial parasite (75% of cases)

Infection of malaria

Reservoir= Humans Intermediate host= Humans Definitive host= Anopheles mosquitoes -plasmodium reproduces sexually only in mosquity Humans are intermediate hosts which means we infect the mosquitoes

Ring-form trophozoites

Seen on thin blood smear of p. falciparum infected people thin and delicate structures within RBCs rings may possess 1 or 2 chromatin dots

How is Malaria diagnosed?

Thick and thin blood smears are stained with GIEMSA STAIN Thick smears = presence of parasites Thin smears= species-level identification P. falciparum contain ring-form trophozoites on thin blood smear