Defined: Plasmodium ovale and different varieties of malaria

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Posted by Anuradha Mascarenhas | Pune |

Updated: December 13, 2020, 8:44:16 am


Malaria is caused by the bite of the female Anopheles mosquito when the mosquito itself is infected with a malaria parasite. (Source: Wikimedia Commons)

A not very common type of malaria, Plasmodium ovale, was identified in a jawan in Kerala. The soldier is believed to have contracted it during his posting to Sudan, from where he returned almost a year ago and where Plasmodium ovale is endemic.

Types of malaria

Malaria is caused by the bite of the female Anopheles mosquito when the mosquito itself is infected with a malaria parasite. There are five types of malaria parasites – Plasmodium falciparum, Plasmodium vivax (the most common), Plasmodium malariae, Plasmodium ovale, and Plasmodium knowlesi. Therefore, to say that someone has Plasmodium ovale malaria means that the person has been infected by that particular parasite.

In India, according to a health ministry statement of 1.57 lakh malaria cases in high-load states Odisha, Chhattisgarh, Jharkhand, Meghalaya and Madhya Pradesh in 2019, 1.1 lakh cases (70%) of falciparum malaria were on Jan. . December. In 2018, the National Vector-Borne Disease Control Program (NVBDCP) estimated that approximately 5 lakh had malaria (63% were from Plasmodium falciparum); Researchers who wrote in the Malaria Journal of BMC felt the numbers could be underestimated. According to the latest World Malaria Report 2020, cases in India fell from around 20 million in 2000 to around 5.6 million in 2019.

Plasmodium ovale

Scientists said P ovale rarely causes serious illness and there is no need to panic based on the case found in Kerala. Dr. VS Chauhan, professor emeritus at the International Center for Genetic Engineering and Biotechnology in New Delhi, said P ovale is very similar to P vivax, which is not a killer form. Symptoms include fever for 48 hours, headache, and nausea. The method of treatment is the same as for a person infected with P vivax. P ovale is no more dangerous than a viral infection, he said.

It is called oval because about 20% of the cells that are parasitized are oval in shape. Differentiating between P vivax and P ovale may be difficult, said Dr. Chauhan, but a good quality laboratory should be able to distinguish between the two. 📣 Follow the express explained in the telegram

Cases in India

According to scientists from the National Institute for Malaria Research (NIMR), the Kerala case may be isolated and there are no recorded cases of local transmission to date. Individual cases were previously reported in Gujarat, Kolkata, Odisha and Delhi. However, no local broadcast was recorded – meaning these cases have been recorded.

The Jawan had returned to India from Sudan in January of this year and was in Delhi. He went to Kerala a month ago and soon afterwards he developed a fever and other symptoms. After the Covid-19 tests were negative, he was tested for malaria.

“And on the slide we could see the parasite in the red blood cell sample. In Kerala, we usually see types of malaria such as Plasmodium falciparum and Plasmodium vivax. So we ran a rapid antigen test to detect the strain and found it was negative for both types. When we investigated further, we diagnosed it as Plasmodium ovale, ”said Dr. Rajeevan, medical superintendent at the Kannur District Hospital where the jaw was treated.

Dr. Rajeevan said it was possible that the parasite could remain in the body’s spleen or liver for long, even years, after the mosquito bite, and the person could later become symptomatic.

Africa and elsewhere

P oval malaria is endemic to tropical West Africa. According to scientists at the NIMR, P ovale is relatively uncommon outside of Africa and, where found, makes up less than 1% of isolates. It has also been detected in the Philippines, Indonesia, and Papua New Guinea, but is still relatively common in these areas.

A 2016 study on the China-Myanmar border found that P ovale and P malariae were very low in prevalence, but were often misidentified. In another study done in Jiangsu Province, China, indigenous malaria cases decreased significantly over the 2011-14 period, but imported P ovale and P malariae cases had increased and were often misdiagnosed.

– Contributions from Vishnu Varma in Kochi & ENS in New Delhi

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