Pre-monsoon rise in dengue and scrub typhus cases alarms entomologistsExperts ask local units to launch awareness drives and focus on cleanliness to lessen outbreak risk.
Although diseases like dengue and scrub typhus have become common in Nepal in recent years, the increased frequency of their infections before the onset of monsoon is alarming, entomologists warn.
As many as 51 districts throughout the country, including districts in the Kathmandu Valley, have reported infection of dengue and scrub typhus since January this year.
All three districts of Kathmandu Valley have reported cases of scrub typhus and Kathmandu and Lalitpur have reported cases of dengue infection, according to Gokarna Dahal, chief of Vector-borne Disease Control Section at the Epidemiology and Disease Control Division.
Dengue is a mosquito-borne disease that is transmitted by female Aedes aegypti and Aedes albopictus mosquitoes. The same vector also transmits chikungunya, yellow fever and Zika viruses, according to the World Health Organisation.
Likewise, scrub typhus, also known as bush typhus, is an infectious disease caused by the parasite Orientia tsutsugamushi, a mite-borne bacterium. It spreads in humans when bitten by infected chiggers (larval mites) found in mice.
The division said that at least 22 districts have reported dengue infection, and scrub typhus has been reported from 29 districts. Officials said that since January, 22 cases of scrub typhus have been reported in Kathmandu Valley—16 in Kathmandu, five in Lalitpur and one in Bhaktapur districts. Similarly, Kathmandu district recorded three cases of dengue infection and Lalitpur one.
“Monsoon is yet to start and we already have so many cases of scrub typhus and dengue infection,” said Sishir Panta, an entomologist at Vector-borne Disease Research and Training Center in Hetauda. “This is not a good sign as a major outbreak can happen at any time. Authorities concerned should take precautionary measures against the risk of major outbreaks.”
Dengue-transmitting mosquitoes breed in clean water and bite people in daylight.
Due to the drinking water crisis, people in the Valley collect water in various types of containers to last for several days. Uncovered water tanks and discarded plastic cups and bottles could become breeding grounds for dengue-carrying mosquitoes.
“Our own studies show that dengue outbreak occurred both in the pre monsoon, monsoon, and post monsoon months,” said Panta. “We can lessen the risks by focusing on cleanliness in big cities and launching awareness about the risk of discarded tires, uncovered water tanks, plastic cups, and bottles.”
Experts warn that garbage piling up on the streets of Kathmandu Valley for many days increases the risk of a major outbreak of dengue virus, as the vector that spreads the virus could easily breed in the rainwater collected in discarded cups, bottles and tyres.
According to doctors, mild to high fever, severe muscle pain, rashes, severe headache, and pain in the eyes are some of the symptoms of dengue, and treatment should be sought immediately if anyone experiences those symptoms. While there is no specific cure for the disease, early detection and access to proper medical care can lower fatalities.
Similarly, infection of scrub typhus can lead to respiratory distress, infection of brain, lungs, kidney failure and then multiorgan failure. If left untreated, it could be fatal.
High fever, headache, abdominal pain, backache, joint and muscle pain, red rashes, nausea and vomiting are some of the symptoms of scrub typhus infection, according to doctors.
Nepal saw a surge in scrub typhus cases after the calamitous 2015 earthquakes that killed nearly 9,000 people.
Three months after the quakes, the BP Koirala Institute of Health Sciences, Dharan had alerted the Epidemiology and Disease Control Division about six children with unusual fever and severe respiratory problems.
Serum samples were collected for subsequent tests in Kathmandu and Bangkok that confirmed a scrub typhus outbreak. By then, four children had already died during treatment. By the end of the year, 101 cases were confirmed in 16 districts and four more people succumbed to the disease.
The magnitude of the outbreak escalated in 2016—831 cases of scrub typhus were reported in 47 districts and 14 people died by the end of that year.
The Ministry of Health and Population said that 296 cases of scrub typhus have been reported since January this year.
Officials at the Epidemiology and Disease Control Division said that the newly elected local government representatives should take outbreak risks seriously and take measures accordingly.
“We have allocated funds to the local governments to launch dengue search-and-destroy campaigns at the local level,” said Dahal of the division. “Awareness drive also plays a crucial role in mitigating the risks.”