Species of Plasmodium which causes Malignant Malaria :

Correct — option (2), Falciparum.

Malignant malaria is the name for malaria caused by Plasmodium falciparum. An Etymologia note in Emerging Infectious Diseases (February 2021), the journal of the US CDC, by authors from ICMR's National Institute of Malaria Research, New Delhi, says falciparum "is the parasite that causes malignant tertian malaria in humans".

The World Health Organization's malaria fact sheet describes how severe this species is: "P. falciparum is the deadliest malaria parasite". Left untreated, P. falciparum malaria can progress to severe illness and death within 24 hours.

So the species behind malignant malaria is Falciparum.

The idea to remember: falciparum causes malignant malaria and is the deadliest species; vivax, ovale and malariae are other species that infect humans.

Why the others are wrong

• (1)
  Vivax — Plasmodium vivax is a human malaria parasite, but not the one named for malignant malaria. WHO describes P. vivax as the dominant malaria parasite in most countries outside of sub-Saharan Africa.

  WHO groups P. falciparum and P. vivax as the two species that pose the greatest threat, and names P. falciparum alone as the deadliest.

• (3)
  Ovale — Plasmodium ovale is one of the malaria species that can infect humans. WHO lists it with P. malariae and P. knowlesi as the other human malaria species, after the two that pose the greatest threat, P. falciparum and P. vivax.

  The malignant form of malaria is the one caused by P. falciparum.

• (4)
  Malarial — Option (4) is printed as "Malarial". The species name it resembles is Plasmodium malariae, which WHO lists among the malaria species that can infect humans.

  It is not the species that causes malignant malaria. That description belongs to P. falciparum, which WHO calls the deadliest malaria parasite.

Malaria is caused by Plasmodium parasites. WHO says five Plasmodium species cause malaria in humans: P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi.

The parasite and the carrier are different organisms. Malaria mostly spreads to people through the bites of some infected female Anopheles mosquitoes; blood transfusion and contaminated needles can also transmit it.

The Emerging Infectious Diseases note derives falciparum from the Latin falx or falci (sickle or scythe-shaped) and parum (like) or parere (to bear). Earlier names such as Haemotozoon falciforme referred to the parasite's sickle-shaped gametocytes; falciparum, suggested by William Henry Welch in 1897, was the name accepted.

Key facts

• WHO: five Plasmodium species cause malaria in humans; P. falciparum and P. vivax pose the greatest threat.
• WHO: P. falciparum is the deadliest malaria parasite; untreated, falciparum malaria can progress to severe illness and death within 24 hours.
• Emerging Infectious Diseases (2021): falciparum is the parasite that causes malignant tertian malaria; the name comes from the Latin falx or falci, sickle or scythe-shaped.
• WHO: P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.
• Malaria mostly spreads through bites of some infected female Anopheles mosquitoes (WHO).

Common traps

• Option (4) prints "Malarial", not a species name. The species it resembles is Plasmodium malariae, which is not the cause of malignant malaria.
• "Deadliest" and "dominant outside sub-Saharan Africa" describe different species in WHO's fact sheet: falciparum and vivax respectively.
• Plasmodium is the parasite; the female Anopheles mosquito is the vector that spreads it. A question can ask for either.

• practice — not a real PYQ

  According to WHO, which Plasmodium species is the dominant malaria parasite in most countries outside of sub-Saharan Africa?

  • (a)P. falciparum
  • (b)P. malariae
  • (c)P. vivax
  • (d)P. knowlesi
  Answer(3) — WHO names P. vivax as the dominant malaria parasite in most countries outside of sub-Saharan Africa. Option (1), P. falciparum, is the deadliest species and the most prevalent on the African continent; options (2) and (4) are among the other species that can infect humans.
• practice — not a real PYQ

  Malaria mostly spreads to people through the bites of some infected:

  • (a)female Aedes mosquitoes
  • (b)female Anopheles mosquitoes
  • (c)sandflies
  • (d)fleas
  Answer(2) — WHO states that malaria mostly spreads through the bites of some infected female Anopheles mosquitoes. Aedes mosquitoes spread dengue and chikungunya viruses, sandflies spread leishmaniasis, and fleas spread plague bacteria, so options (1), (3) and (4) are wrong.