BLOOD AND TISSUES – PLASMODIUM SPECIES

1. Definition: Plasmodium species is a type of parasite responsible for causing malaria in humans → It's a protozoan parasite that infects the red blood cells → Causes fever, chills, and flu-like symptoms.

2. Causes: Plasmodium species is transmitted through the bite of an infected female Anopheles mosquito → When the mosquito bites, it injects the parasites into the human body.

Types of Plasmodium species:

• Plasmodium vivax
• Plasmodium ovale
• Plasmodium malariae
• Plasmodium falciparum (the most deadly species)

3. Life cycle of Plasmodium species:
   1. The parasite is ingested by the mosquito along with a blood meal →
   2. The parasites then undergo sporogony in the mosquito's midgut →
   3. The sporozoites are formed and travel to the salivary glands →
   4. When the mosquito bites a human, the sporozoites are injected into the bloodstream →
   5. The sporozoites then enter the liver cells and undergo schizogony →
   6. The merozoites are formed and infect red blood cells →
   7. The parasites then undergo asexual reproduction and form trophozoites →
   8. The trophozoites then mature into schizonts and release merozoites →
   9. The merozoites infect more red blood cells and the cycle continues →
   10. In the case of P. vivax and P. ovale, some of the parasites form hypnozoites in the liver cells →
   11. Hypnozoites can reactivate later and cause relapses.

Memory trick: "SPORZOITES SLEEP IN THE LIVER, MERZOITES MAKE TROPHOZOITES, TROPHOZOITES BECOME SCHIZONTS, SCHIZONTS RELEASE MERZOITES, AND MERZOITES INFECT RED BLOOD CELLS"

4. Pathogenesis: → The parasites infect the red blood cells and cause damage to the cells → → The infected red blood cells are removed from the circulation by the spleen → → The removal of infected red blood cells can lead to a decrease in the number of red blood cells in the circulation → → This can cause anemia → → The parasites also cause the release of pro-inflammatory cytokines → → This can lead to fever, chills, and flu-like symptoms.

5. Morphology: → The parasites have a distinctive "ring" or "band" shape within the red blood cells → → The ring shape is due to the formation of the parasite's nucleus and the surrounding cytoplasm → → The parasites can also form gametocytes, which are the sexual stage of the parasite → → Gametocytes are responsible for transmitting the parasite to the mosquito.

6. Clinical features of malaria: → Fever, chills, and flu-like symptoms → → Headache, muscle aches, and joint pain → → Nausea and vomiting → → Diarrhea or constipation → → Anemia → → Yellowing of the skin and eyes (jaundice) → → In severe cases, malaria can cause seizures, coma, and death.

7. Complications of malaria: → Anemia → → Jaundice → → Seizures and coma → → Respiratory failure → → Cardiac arrest → → Death.

8. Laboratory diagnosis of malaria: → Thick and thin blood smears are examined for the presence of parasites → → Polymerase chain reaction (PCR) is used to detect the parasite's DNA → → Rapid diagnostic tests (RDTs) are used to detect the parasite's antigens → → Blood tests are used to measure the level of hemoglobin in the blood → → Urine tests are used to detect the presence of the parasite's antigens in the urine.

9. Management of malaria: → Antimalarial medications are used to treat the infection → → The type of medication used depends on the severity of the infection and the type of parasite → → In severe cases, hospitalization may be necessary → → Supportive care, such as hydration and oxygen therapy, may be necessary → → Prevention of mosquito bites through the use of insecticide-treated bed nets and insect repellents can help prevent the spread of malaria.