Malaria on the rise in more than 13 countries, warn experts

In the 10 countries – including Tanzania, Mali, Burkina Faso, Cameroon, Ghana, Uganda and Niger – 3.5 million additional people were diagnosed with malaria in 2017 compared to 2016.

"We are no longer seeing a decrease in malaria as we have done in recent years," said Alistair Robb, senior advisor of WHO's global malaria program. "It's a concern."

The WHO region of the Americas has also seen an increase in malaria cases, mainly due to increases in Brazil, Nicaragua and Venezuela.

Malaria is a parasitic disease transmitted by the bite of anopheles female mosquitoes. It is both preventable and treatable. Yet an estimated 435,000 people died in the world in 2017. The African region accounts for 92 percent of all cases, according to the report.

Some countries have experienced a significant decline in the number of reported cases, including India, Pakistan, Ethiopia, and Rwanda. India has reported 3 million fewer cases and Rwanda 430,000 less in 2017, according to the report. Experts cite these countries as examples, especially for those whose caseload is increasing.

Success in these four countries has translated into political engagement, reaching out to marginalized populations and effective use of resources such as mosquito nets and mosquito nets. drugs, explained Robb. In many parts of Africa, "a large number of people still do not have access".

In heavily-affected African countries, the most needy populations – marginalized and vulnerable communities – can not access treatment and prevention resources, he added, exposing them to the risk of infection. In 2017, about half of those at risk of contracting the disease in Africa did not sleep under treated mosquito nets, according to the report.

"We have distributed tools where we can," said Dyann Wirth, professor of immunology and infectious diseases at Harvard T.H. Chan School of Public Health. Now strategies need to be rethought because there are problems to be treated differently, she said.

"If we just continue to do the same thing, we risk a significant rebound," said Wirth.

Maintain – do not sit – succeed

"You can not be content with yourself," Robb said, citing Nicaragua and Venezuela, which have seen an increase in the number of malaria cases in the last three years, and in Brazil in the past two years.

Venezuela experienced a strong increase on the continent, with 411,000 cases in 2017, against 136,000 in 2015.

However, South America as a whole has a low malaria burden – less than 2% of the global burden – resulting in a different pattern of transmission, explained Robb.

People there have less natural immunity to malaria, he said, making them more vulnerable as a population. If resources are not maintained, this can lead to a significant increase in the number of cases.

"The introduction of an infected person can trigger an epidemic," Wirth said.

When the levels are also low, the perceived risk is reduced, she explained, so that people are less likely to use mosquito nets to protect themselves from mosquito bites, for example. "Take care is important."

Wirth gave the example of Sri Lanka, which had an extremely low number of cases in the 1960s, but saw them rebound in the 1970s and 1980s. "It took 35 years to eliminate again." Sri Lanka has been declared free of malaria in 2016.

Venezuela is now facing the same challenge, she said.

"It's very important that we recognize that progress has stagnated," said Wirth. "Countries reporting an increase in the number of cases are an early warning."