Last year there were an estimated 249 million cases of malaria worldwide. the World Health Organization announced on Thursdaysignificantly more than before the Covid-19 pandemic and an increase of five million compared to 2021. Malaria remains one of the most common causes of death in children.

These new cases were concentrated in just five countries: Pakistan, Nigeria, Uganda, Ethiopia and Papua New Guinea. Climate change was the direct trigger for three of them, said Dr. Daniel Ngamije, who heads the WHO’s malaria program.

In July 2022, massive floods inundated more than a third of Pakistan and displaced 33 million people. An explosion of mosquitoes soon followed. The country reported 3.1 million confirmed malaria cases this year, compared with 275,000 the year before, a five-fold increase in the transmission rate.

“Given the very heavy monsoons, we had expected these consequences, but not to this extent,” said Dr. Muhammad Mukhtar, Director of Pakistan’s National Malaria Control Program.

While flooding has receded in some areas, there are still large areas of standing water, and the malaria parasite is now well established and circulating in communities that previously had little immunity, Dr. Mukhtar.

More than seven million mosquito nets have been distributed to displaced people, but people living in small tents or large, crowded halls have nowhere to hang them, Dr. Mukhtar. The country relies on spraying insecticides and mass administration of antimalarial drugs to combat mosquitoes.

Pakistan has confirmed 2.3 million malaria cases so far this year and expects the total to be even higher than the total from 2022.

“It will take another one or two years for the situation to normalize, unless, God forbid, another natural disaster occurs,” said Dr. Mukhtar.

In Pakistan, as in other places where weather disasters fueled the spread of malaria, new mosquito habitat was only part of the problem. The floods damaged 2,200 health facilities and left millions of people in affected districts unable to access medical treatment.

The number of deaths from malaria remained largely stable worldwide between 2021 and 2022, but at an estimated 608,000 was still well above the total of 576,000 in 2019, i.e. before the Covid pandemic.

The number of deaths fell steadily from 2000 to 2015 as major efforts were made to make better diagnostics and treatment methods, as well as insecticide-treated bed nets, widely available in malaria-affected areas of sub-Saharan Africa. But growing resistance to these drugs and insecticides, along with stagnant funding and changes in mosquito behavior, have joined forces to stop this progress. Covid has further disrupted both healthcare services and supply chains.

Climate change is also at least partially responsible for an increase in malaria in Ethiopia (with 1.3 million more cases than last year) and Uganda (with 600,000 more), said Dr. Ngamije from the WHO. Highland areas that have long been too cool and dry to allow malaria-carrying mosquitoes to breed have begun reporting cases in these two countries.

In Ethiopia, major civil wars resulted in millions of people being displaced, making them once again vulnerable to malaria. Conflicts also drove the spread of malaria in other areas: in Myanmar, for example, cases rose more than sevenfold.

And Ethiopia is one of the African countries where an invasive mosquito species, Anopheles stephensithat thrives in urban areas that were once largely free of malaria is now spreading the disease.

There are worrying signs of this in Uganda too The malaria parasite develops resistance to the main drug used to treat the disease.

Nigeria, the country with the highest malaria burden, also experienced extreme flooding in 2022. The country was able to keep the rate of new infections stable, but rapid population growth led to an additional 1.3 million cases.

Climate change is also driving malaria cases, with people displaced by drought, heatwaves and storms and left in substandard housing, Dr. Ngamije. Weather disasters disrupt supply chains for malaria tests, treatments and insecticides. Increasing food insecurity in sub-Saharan Africa due to floods and droughts is leaving more children malnourished and therefore more vulnerable to severe malaria. Repeated malaria infections keep children from going to school and wipe out the savings of the lowest-income families in affected countries.

The malaria report actually contained some good news. Azerbaijan, Belize and Tajikistan were certified malaria-free by the WHO in 2022.

More than two million children in Ghana, Kenya and Malawi had received at least one dose of a new malaria vaccine by the end of 2022. Vaccination protection will be expanded to twelve more countries next year. There was a 13 percent decrease in child mortality over four years in the areas where the first malaria vaccine was administered.

Dr. Ngamije said he had hoped that malaria data for 2022 would show a decline rather than an increase in global cases. But the WHO’s approval of a second malaria vaccine, which will rapidly increase supply, as well as the increasing availability of bed nets treated with various types of chemicals to counteract the effects of insecticide resistance, make him optimistic that there will be one in the next There will be significant progress this year.

“If it’s a normal year,” he said.