Contain Dengue Transmission Risk

With the onset of monsoon, more cases of dengue have been reported across Nepal, posing a higher risk of this deadly mosquito-borne disease being transmitted as an epidemic. As the country is expected to witness more than average rainfall this monsoon, health authorities have already warned that there is a possibility that this virus disease may emerge as a serious public health concern. In pre-monsoon and rainy season, there are greater chances for the population of mosquito species carrying dengue virus to increase rapidly. Until some years in the past, dengue was a seasonal disease. But because of rapid urbanisation and global warming, dengue has begun posing a threat year-round. Modification in mosquito behaviour is another factor leading to an increased risk of dengue infection almost throughout the year. 

Rising cases

The latest data released by the Epidemiology and Disease Control Division (EDCD) under the Department of Health Services indicate that dengue has spread to 73 districts over the past six months or so. Many dengue cases have been traced in different districts. However, four Himalayan districts – Humla, Jumla, Dolpa and Mustang – have yet to report any dengue infections this year. Among provinces, Bagmati has recorded 482 cases since the start of 2024. This is the highest figure. With about 350 dengue infections, the Koshi Province is now in the second position in terms of the number of cases. The disease is likely to spread faster in the days ahead as the ongoing heavy rains have made many areas, especially in the Terai districts, waterlogged. Still waters are the main breeding grounds for mosquito species.  

Health scientists say that dengue is mostly spread to humans by mosquitoes belonging to Aedes aegypti and Aedes albopictus species. Nepal reported the first dengue case in 2004. A foreigner was found infected with this viral disease in Chitwan. Over the past two decades, the nation has witnessed hundreds of thousands of dengue infections. In the initial years, the disease was limited to the hot and humid Terai districts. But with the passage of time, this disease has been found being spread even to several hilly and mountainous districts. This is mainly because of climate change effects and the changing behaviour of mosquitoes. With a continuous rise in temperatures even in the hilly and Himalayan districts, the population of the mosquitoes carrying dengue virus has increased there. Such mosquitoes have also been able to adapt themselves to the cold weather. 

Despite this, the death rate is not very significant. But many patients suffering from this disease are likely to find their health condition being deteriorated startlingly as their level of immunity falls down. High fever, severe headaches, vomiting, pain behind eyes, joint, bone and muscle pains, swollen glands and rash skins are some of the key symptoms of dengue. No specific medicine has been developed for the treatment of the patients infected with dengue. Doctors advise patients to use only paracitamol for controlling the high fever caused by this disease. When one catches dengue repeatedly, there is a higher chance for his/her health condition to worsen further. A patient of severe dengue may show symptoms like severe abdominal pain, persistent vomiting, bleeding gums, vomiting blood, rapid breathing and restless. 

In 2016, Jhapa, Chitwan and Rupandehi districts came out to be dengue epicentres. During that year, the disease was transmitted to numerous districts across the country. But the situation continued to worsen in the following years. In 2020, dengue cases were found in all the 43 districts, with thousands of infections and 12 deaths. In 2022, the disease spread to all the 77 districts, infecting more than 54,000 people nationwide. Some 90 dengue-related deaths were recorded that year. Dengue wreaked havoc on Dharan where more than 18,000 cases and several deaths were recorded. The Kathmandu Valley was also a dengue epicentre, with many infections. Hospitals were full of dengue patients. There was an acute scarcity of paracetamol in the valley. The Koshi Province saw an alarming rise in the number of dengue infections in 2023. As many as 20 people succumbed to this viral disease there. Sunsari was the most affected among the districts in the province. About 31 per cent of cases were recorded in Sunsari alone.

What is worrying is that the number of dengue infections per 100,000 populations has been on the rise at an alarming rate over the years. Statistics show that there were just three cases per 100,000 populations in 2018. The figure increased to 60, 185 and 178 per 100,000 populations in 2019, 2022 and 2023, respectively. This really hints at a rapid surge in the number of dengue infections every year. This calls for necessary preventive and control measures.

Prevention

Open water tanks, unwanted cups, plastics storages for scrap materials and unused lands can be possible breeding grounds for the mosquitoes carrying dengue virus. So, everyone must ensure that there are no such mosquito hotspots in their houses and the surroundings in order to prevent the breeding of larvae. More people may lose their lives to dengue infection if effective measures are not taken right now to create awareness. Prevention of mosquito larvae and expanding health facilities are also essential. 

It is notable that some local governments, including the Kathmandu Metropolitan City (KMC), have launched a search-and-destroy campaign in view of the current difficult situation. Under this drive, they have wanted to search the mosquito larvae and destroy them. With this initiative, they have also aimed to raise public awareness against the dengue virus. The federal and provincial governments should also join forces with the local government to make this campaign a success. 

(The author is a former deputy executive editor of this daily.)