PETALING JAYA – The spike in malaria cases in several parts of Malaysia in 2023 is causing concern among public health experts, who cite climate change as one of the contributory factors.

The number of cases so far in 2023 has already exceeded the 404 reported in the whole of 2022.

As at June 2023, there were 215 cases reported in Kelantan and 840 cases in Sabah, while Terengganu reported 26 cases over the first five months of the year.

These are worrying statistics after Malaysia recorded zero human malaria infections from 2018 to 2021.

The rise in malaria cases also comes as the country is dealing with an increase in dengue cases because of the hotter and drier weather caused by the El Nino weather phenomenon.

Malaria is caused by a parasite transmitted through the bite of an infected female Anopheles mosquito.

Health experts said zoonotic malaria – carried by monkeys and spread to humans through mosquito bites – remains a concern, and they have called for mass blood screening in affected areas.

Zoonotic transmission of malaria usually affects people residing near forest fringes, plantations and agricultural sites, including those involved in activities such as logging, fishing, planting and hunting-gathering.

Public health expert Zainal Ariffin Omar said climate change and deforestation could be among the contributing factors.

“It could also be due to people moving nearer to places that are a source of malaria,” said the former Health Ministry official.

Universiti Kebangsaan Malaysia’s Professor Sharifa Ezat Wan Puteh said warmer temperatures and changes in rainfall patterns due to climate change, as well as changes in the behaviour of mosquitoes carrying malaria, could also be factors contributing to the increase in cases.

“In Kelantan, however, this could be more due to human-animal conflict,” she added.

She said that while Malaysia has entered the phase of eliminating the indigenous transmission of malaria, zoonotic malaria transmitted from macaque monkeys remains a public health problem.

“Indigenous transmission” is the mosquito-borne transmission of malaria in a geographic area where malaria occurs regularly.

“The parasite known as Plasmodium knowlesi is usually carried by macaque monkeys and spreads to people when a mosquito bites an infected macaque and then bites a person,” Prof Sharifa said.

“This happens during logging, fishing, planting, deforestation or when entering a jungle. Monkeys also travel to nearby houses and villages and spread the parasite. It is also known as simian malaria.”

Prof Sharifa said delays in seeking medical attention and a lack of preventive measures such as putting up mosquito nets might lead to a further increase in cases.

She added that the disease could also be transmitted via the migration of people from malaria-prone countries to Malaysia.

She proposed that the government conduct mass blood screenings to detect the malaria parasite among workers in affected areas in Kelantan.

“We also need to keep a watchful eye on full-blown malaria cases, especially among children.”

Prof Sharifa said the resistance of malaria parasites to anti-malaria treatment drugs has also heightened the threat of the disease.

On Sept 25, Kelantan Health Department director Zaini Hussin said the state had recorded 215 malaria cases so far in 2023, an increase of 98 cases – or 84 per cent – compared with the same period in 2022.

Of these, 53 were human malaria infections and 162 involved zoonotic transmissions. However, there have been no malaria-related fatalities reported in the state so far.

Datuk Zaini said frequent exposure to forests and plantations was among the factors leading to the increase in malaria infections in Kelantan.

Of Sabah’s malaria cases, 816 involved zoonotic malaria, 14 were imported human malaria cases, and 10 were human-introduced malaria infections.

On March 14, Health Minister Zaliha Mustafa said the country is facing a new threat in the form of a rising number of zoonotic malaria cases. THE STAR/ASIA NEWS NETWORK