Sri Lanka’s Deadly Dengue Fever Outbreak Is ‘Three Times’ Worse Than Previous Years

Sri Lanka is facing an unprecedented outbreak of dengue fever, which has resulted in more than 100,000 cases and claimed almost 300 lives so far this year. Aid groups say that the onslaught of cases is overwhelming the island nation’s medical system.

As of Monday, 105,153 dengue fever cases have been reported across Sri Lanka, according to numbers from the Epidemiology Unit of the country’s Ministry of Health. That is almost double the total case count in the entire year of 2016, which stands at 55,150. A total of 296 people have died from the mosquito-borne epidemic so far.

The populous Western Province — including Colombo, the country’s capital city — is the worst hit, with more than 46,000 cases reported so far, making up around 44% of the country’s total. The spike in dengue cases coincides with the monsoon season and comes in the wake of torrential rains and flooding, according to the World Health Organization (WHO). The group explained that the high number of cases in suburban and urban areas is linked to the accumulation of trash soaked with rainwater and puddles of still water. Both situations create ideal breeding grounds for mosquitoes.

“This is unusual,” Gerhard Tauscher, operations manager of the International Federation of Red Cross and Red Crescent Societies (IFRC) in Sri Lanka tells TIME. “There’s always a peak [in dengue fever cases] during rainy seasons, but this one is three times higher.”

He adds that the concentration of cases in Western Province “has to do with population density,” as well as a concentration of rainfall on that part of the country.

Compounding the problem for Sri Lanka is the prevalent strain of dengue virus in this particular wave, which, according to the WHO, had only been identified in low numbers in the country since 2009.

“Dengue is endemic here, but one reason for the dramatic rise in cases is that the virus currently spreading has evolved and people lack the immunity to fight off the new strain,” Dr. Novil Wijesekara, Head of Health at the Sri Lanka Red Cross, said in a statement released Monday.

The IFRC announced Monday that it is releasing extra funding for the Sri Lanka Red Cross to ramp up its response, which includes providing medical care, raising public awareness in identifying dengue fever symptoms and preventing its spread, as well as eradicating possible breeding spots for mosquitoes. “Dengue patients are streaming into overcrowded hospitals that are stretched beyond capacity and struggling to cope,” the group said in a statement.

The Red Cross intervention follows Australia’s announcement last week that it would provide help to Colombo in fighting the outbreak.

Spread through mosquito bites, the dengue virus causes flu-like symptoms, and can occasionally develop into a severe form called dengue hemorrhagic fever. Its incidence worldwide has seen explosive growth in recent decades, according to the WHO — the dengue virus is now endemic in over 100 countries, with an estimated 390 million infections every year.

Tauscher expects that there would eventually be an end to the current boom in dengue cases across the country, telling TIME that “it will probably drop in four to six weeks, when the rain stops.”