Plasmodium and Malaria

Last Updated on May 5, 2020 by Sagar Aryal

The early history of Plasmodium and Malaria

In the past time, it was believed that malaria spread by bad air hence the name means bad air. In 1880 Malaria parasites firstly discovered by a french doctor, Charles Laveran. In 1897 Ronald Ross worked on avian malarial parasites (P. praecox), Ronald Ross was awarded Noble prize in physiology & medicine in 1902. Italian malariologists, Giovanni Battista, Grassi, Amico Bignami, Giuseppe Bastianelli, Angelo Celli, Golgi & Ettore Marchiafava, conclude that Malaria spread by mosquitoes 1898.

Plasmodium and Malaria

Figure: The life cycle of the malaria parasite. Image Source: Wikipedia.

Plasmodium species (the parasites of malaria)

We all known that Genus Plasmodium has several species causing malaria 4 main species causing human malaria is P. vivax, P. malariae, P. ovale, and P. falciparum.

Plasmodium vivax

World widely distributed but mainly occurs in sub-tropical & warmer temperate regions. It has 8 days of duration of the pre-erythrocytic cycle. The size of the signet-ring is 1/3 diameter of R.B.C., & a number of chromatin dots are single. Haemozoin pigment is yellowish-brown with fine granules and rodlets.

Plasmodium malariae

It is also worldwide distribution but mainly occurs in tropical and sub-tropical regions. Its pre-patent period (pre-erythrocytic cycle duration) is 7-12 days. Its signet ring also 1/3 of RBC diameter and having 1 dot of chromatin. Haemozoin is dark brown to black and abundant coarse granules.

Plasmodium ovale

Mainly found in tropical Africa. The duration of the pre-erythrocytic cycle is 9 days. Likely 2 before discussed species, it’s signet ring is also 1/3 of RBC diameter and usually one ring & one dot. Pigment (hemozoin) is dark brown, less abundant coarse granules.

Plasmodium falciparum

World wide distributed, mainly in tropical, sub-tropical, and warmer temperate regions. The signet ring is at the edge of RBC. Some-times 2 chromatin dots. Dark brown or black coarse granules around the nucleus.

Types of Malaria

1- Tertian, benign tertian

Causative species- Plasmodium vivax

Symptoms- occurrence of fever after (48) every third day, does not lead to death

2- Quartan malaria

Causative species – Plasmodium malariae

Symptoms- Frequency of fever every fourth-day (72 hours). It has the longevity of 40 years or more in untreated persons, chronic infection some time lead to lethal kidney conditions, but ordinary infection does not prove fatal.

3- Ovale or mild tertian Malaria

Causative species- Plasmodium ovale

Symptoms-  Symptoms resembling with tertian malaria and fever occur every 3rd day (48 hours). It is not more harmful and mainly found in tropical Africa.

4- Aestivo – autumnal, malignant tertian or pernicious malaria

Causative species- Plasmodium falciparum

Symptoms- Fever frequency at 48 hours. It is often a fatal type of malaria affecting the brain of the patient.

5- Quotidian malaria

Causative species- More than one species of Plasmodium or 2-3 generation of parasites mature on successive days.

Symptoms- Fever repeated daily with an interval of 24 hours.

Pathogenesis and Symptoms of Malaria

Symptoms appear after an incubation period (several days after infection). Symptoms appear when a large number of parasites organisms continue erythrocytic cycle at a time. Attacks of fever have three successive stages.

1- Cold stage

It has a time of 20 minutes to hours. In this phase, the patient suffers chill and shivering while he/she covered in blankets.

2- Hot stage

After the chill, hot stage start, body temperature rise up-to 41°C / 106°F. This phase ends within 1-4 hours. The patient feels hot with the headache.

3- Sweating stage

After the hot stage, sweating stage set-up, patient sweat, and fever come down temperature becomes normal

Blackwater fever and relation to Malaria

In this disease, RBC breaks down and hemoglobin excreted in the urine, also called “malarial hemoglobinuria”.  John Farrell Easmon, link this disease to Malaria. It is caused by the rapid and massive destruction of RBC and leads to hemoglobinuria, jaundice, anuria ( less than 50 ml of urine/day), and finally death. It may be caused by an autoimmune reaction of the plasmodium and antimalarial drug “quinine”. It is also caused by parasitization of RBC by Plasmodium falciparum when parasites are present more in number.

References

  1. Kotpal RL. 2017. Modern Text Book of Zoology- Invertebrates. 11th Edition. Rastogi Publications.
  2. Cox FE. History of the discovery of the malaria parasites and their vectors. Parasit Vectors. 2010;3(1):5. Published 2010 Feb 1. doi:10.1186/1756-3305-3-5

Sources

  • 2% – https://parasitesandvectors.biomedcentral.com/articles/10.1186/1756-3305-3-5
  • 2% – https://en.wikipedia.org/wiki/Ronald_Ross
  • 1% – https://www.sciencedirect.com/topics/medicine-and-dentistry/plasmodium
  • 1% – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3340990/
  • 1% – https://en.wikipedia.org/wiki/Blackwater_fever
  • 1% – http://medcraveonline.com/MOJAP/MOJAP-02-00048.pdf

Plasmodium and Malaria

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