Only five cases of malaria but the US CDC issued an alert

Subject : Science and technology

Section: Health

Context:

The United States has identified five cases of malaria in people without any history of international travel in Florida and Texas over the past two months. This has led to the US Centres for Disease Control and Prevention (CDC) issuing an alert.

Why the alert?

Because this is the first time in 20 years that there has been local transmission of malaria in the United States.
The last time the infection was transmitted by a mosquito locally in the country was in 2003.
The US reports around 2,000 cases of malaria every year, mostly among international travellers from regions where the disease is in transmission.

Malaria disease:

Malaria is a parasitic infection transmitted by the bite of an infected anopheles mosquito; in the US, while the mosquito is found, the parasite is usually not.
There are five plasmodiums that can cause malaria in humans – p. falciparum,
p. vivax, p. malariae, p. ovale, and p. knowlesi.
P. falciparum is the deadliest, resulting in several complications, including cerebral malaria
Its cases are mostly seen on the African continent.
Outside the continent, p. vivax causes most cases. Though not as deadly as p. falciparum, it poses a unique challenge as the parasite is capable of laying dormant in the liver for extended periods.

Status of malaria in the world:

Nearly half of the world’s population continued to be at risk from the infection in 2021, according to the latest available World Malaria Report.
The report said there were an estimated 247 million cases across the world and 619,000 deaths due to malaria during the year. Around 95% of these cases were from the African region.

How does India fare?

Although malaria has been on the decline in India – there was an 85.1% decline in malaria cases and an 83.36% decline in deaths between 2015 and 2022– the country still has a high burden of infection.
In 2021, 1.7% of the malaria cases in the world and 1.2% of all the deaths were reported in India.
The country accounted for 79% of the malaria cases and 83% of the deaths from the WHO Southeast Asia region.
India has a high burden of difficult-to-treat p. vivax infections.

Could there be a resurgence of malaria due to climate change?

Climate had a very important role to play in the transmission of vector-borne disease.
The mosquitoes that transmit malaria are very sensitive to temperatures, they can thrive only in certain not-too-hot and not-too-cold temperatures.
Due to the rise in temperature malaria cases in colder regions can be increased potentially.