Malarial parasite Life cycle A bad thing happens Commentary

Charles Louis Alphonse Laveran, Patrick Manson, Ronald Ross parasitology

Malarial parasite

• Ronald Ross found the eggs of the parasite
• in the stomach wall of a specific species of mosquito
• and showed that they got there by feeding on the blood
• of a man with malaria.
• Alphonse Laveran had already, in 1880,
• discovered the malarial parasite,
• and Patrick Manson had suggested, in 1894,
• that malaria was transmitted by mosquitoes.

Life cycle

• A female mosquito of the species Anopheles,
• to get protein to produce her eggs,
• sucks human blood.
• To reduce clotting and constriction of your blood vessels,
• the mosquito injects her saliva,
• infected with sporozoites, beneath your skin,
• from where the sporozoites migrate into your bloodstream.
• The sporozoites collect in your liver
• where they invade cells and set up homes,
• transform into a rounded form,
• and mature into schizonts containing many merozoites.
• Merosomes bud off the infected liver cells
• and these lodge in capillaries of the lungs
• where they disintegrate, releasing thousands of merozoites,
• which invade red blood cells.
• In red blood cells, the merozoites
• transform into ring-shaped and trophozoite forms
• and they divide several times into new merozoites
• that escape and invade other red blood cells.
• Some merozoites get into your bone marrow,
• change into male or female gametocytes,
• then freely circulate in your blood,
• which the female mosquito sucks up.
• In the mosquito’s midgut,
• the gametocytes change into gametes,
• fertilize each oher, become diploid zygotes,
• and transform into invasive ookinetes that escape the gut.
• Outside the gut, they invade cells and set up homes
• where they divide and produce thousands of sporozoites.
• The sporozoites migrate to the salivary glands
• from where they are injected into their next host.

A bad thing happens

• Mosquitoes suck
• as if there were good and bad.
• You do not like the parasite
• and neither does the mosquito.
• It is unfortunate that humans
• make such good hosts for this worm.