For Prabina Maharjan, it started with a headache, which then turned into fever and body pain.
When she finally turned up at the Sukraraj Tropical and Infectious Disease Hospital a week ago, tests showed something odd for this high-elevation city: dengue fever, a scourge more associated with Nepal’s low-lying tropics.
But as climate change brings hotter temperatures, disease threats are shifting – and this year Kathmandu, Nepal’s capital in the Himalayan foothills, is seeing an unprecedented surge of dengue.
In just the first week of September, more than 1,000 cases of the fever were diagnosed at the city’s Sukraraj Tropical and Infectious Disease Hospital, a quarter of them contracted in the Kathmandu area, said Anup Bastola, the hospital’s chief tropical medicine consultant.
In previous years, the hospital mainly has seen cases of the painful and occasionally fatal disease in people coming from Nepal’s southern lowlands, he said.
“But this year we saw many cases from the Kathmandu Valley itself,” he added.
In a city that has never faced such a large local outbreak, fear of dengue is so rife that people are flooding to hospitals for testing, even if they turn out to have a simple headache or seasonal flu, the doctor said.
“The flow of patient is so high that the staff are busy testing blood samples up until late in the night,” Bastola said.
Those in the testing lines included 39-year-old Maharjan’s mother and son, who also turned out to have caught the mosquito-carried illness, though weren’t hospitalised for a week as she was.
“We were astonished to be infected by a disease that is generally considered a disease of the Terai,” said Maharjan, referring to a southern tropical region of Nepal.
Like many, she is puzzled why the disease is now taking off in hilly Kathmandu, which lies at 1,400 metres (4,600 feet).
“There were mosquitoes in the valley in past years too, but we never heard about the outbreak of this disease in such a large scale,” Maharjan said.
MORE HEAT, LESS KNOWLEDGE
As climate change brings hotter conditions in many countries, health threats are rapidly changing, with many authorities underprepared, international public health officials warn.
According to data published by Nepal’s disease control division, more than 250 cases of locally contracted dengue were detected in the Kathmandu Valley between mid-July and early September, two of them fatal.
Last year, the valley saw only six cases, according to the agency’s figures.
Meghnath Dhimal, chief research officer at the government’s Nepal Health Research Council, said rising temperatures associated with climate change are the major driver of the new threat.
“In Nepal, the first outbreak of this disease occurred in 2006, when only five districts were affected. But this year the disease was found in 56 out of 77 districts,” he said.
Warmer conditions help spread the disease both by making it easier for mosquitoes to reproduce, and by spurring the virus itself to replicate faster.
But “migration of infected mosquitoes and human cases from the tropical parts (of Nepal) plays a role in seeding the disease” in new areas, he said.
Because there is no vaccine or particular medicine to treat dengue, reducing the number of mosquitoes is the main way to reduce its spread, Dhimal said.
But Nepal’s government, confronted with a fast-rising threat, so far has not put in place enough programs to do that, he said.
“As the highlands were rarely previously affected by dengue, people and government official are not well-prepared to prevent and control the disease” he said.
In most cases, efforts to battle the problem start “only after it has gained ground”, he said.
That means “the insects that are not eliminated this year will (lay eggs and) surge again next year after it starts getting to a favourable temperature,” Dhimal said.
Another obstacle in controlling the disease is simply the lack of awareness of many people about the emerging threat.
For example, residents may protect themselves against mosquito bites at night, but the dengue-carrying mosquito bites during the day, something few people in Kathmandu know, he said.
A study he led in 2012 found people in lowland Nepal were five times more likely than people in highland areas to understand dengue risks.
If highland Nepal is to successfully fight back against dengue, “awareness of people and control of the vector by effective government action and community mobilisation can be the only effective step”, Dhimal said.