Unpredictable weather marked by intense heat and sudden rainfall has increased the risk of spread of communicable diseases like dengue and malaria, health experts warn. This year’s rainfall is expected to be heavier than usual, which could intensify the spread of mosquito-borne illnesses, particularly dengue.

Dengue fever is a viral illness transmitted through the bite of an infected mosquito, specifically one carrying the dengue virus (DENV). The illness is most prevalent in tropical and subtropical regions, including parts of Asia, Central and South America, Africa, and the Pacific Islands. With the anticipated rise in rainfall, health authorities are urging the public to take preventive measures to avoid a potential outbreak.

This year the monsoon is expected to arrive in the third week of June, and the rainfall is estimated to be 5 percent above average. Eastern Nepal (Mechi, Koshi, Sagarmatha) is expected to receive 5–10 percent more rainfall, central Nepal (Janakpur, Bagmati, Narayani, Gandaki, and Lumbini) 4–6 percent more, and western and far-western regions are expected to receive average rainfall.

According to the World Health Organization, every year around 100–400m people get infected by Dengue from all around the world. In 2022, Nepal saw one of its worst dengue outbreaks in history: 52,557 confirmed cases and 60 deaths, according to official government statistics. While numbers dropped in 2024, the Epidemiology and Disease Control Division (EDCD) reported 34,385 cases and 13 deaths, affecting 76 districts across the country.

Since the first reported case of dengue in Nepal in 2004, the number of infections has been steadily increasing each year. To combat this growing health threat, early detection, diagnosis, management, and reporting have become essential. A regular surveillance and monitoring system has been implemented through an early warning and reporting mechanism.

Mosquito surveillance is also being strengthened through integrated vector management strategies. Integrated Vector Management (IVM) is a strategic approach to controlling vectors that transmit diseases like malaria, dengue, and Zika. It combines various control methods, including biological, chemical, environmental, and public health education, to optimize resource use and achieve sustainable vector control.

To support timely diagnosis, dengue rapid test kits have been made available free of charge at government health institutions. Furthermore, a comprehensive dengue prevention and control action plan has been approved and published by the EDCD on the occasion of World Neglected Tropical Diseases Day 2025.

Dr Sher Bahadur Pun, chief of the Clinical Research Unit at Sukraraj Tropical and Infectious Disease Hospital said: “Dengue might break out at any time during the monsoon season. One should take necessary precautions and the authorities concerned should have a good preparedness plan to stop the outbreak.”

To prevent dengue, it is important to take both personal and environmental precautions. Personal protection methods include using mosquito repellents, electronic mosquito-killing machines, mosquito nets and electric bats. Maintaining a clean and hygienic environment is equally important.

Dr Pun emphasized that while using items like above can help prevent mosquito bites, people should not rely solely on them. “These methods only deter mosquitoes temporarily and do not eliminate them,” he said, stressing the need for long-term preventive measures, such as maintaining cleanliness and preventing water stagnation in and around homes that serve as a breeding ground for mosquitoes. 

Province wise Dengue Cases (January-December 2024)

Source: Epidemiology and Disease control Division (EDCD)