Description of the Event
Approximate date of impact
In Nepal, dengue cases usually increase in July, coinciding with monsoon season, falling between June and September, with most cases reported in September. Hence, the approximate impact will be from July to September 2023, with 3,500 to 4,000 cases reported, as projected by the Ministry of Health and Population (MoHP). This year, as per epidemiological data collected up to April 2023, 600 cases have already been diagnosed which is highly alarming considering the usual incidence pattern in Nepal.
What is expected to happen?
Up to April 2023, 600 dengue (EWARS report, EDCD) cases have already been diagnosed, which is highly alarming as this is the very first time that dengue has occurred in a consecutive year, contrary to the usual cyclical pattern of dengue incidence in Nepal. On comparison of data between January to April 2022 and 2023, only 17 cases were reported in 2022, while over 600 cases have already been reported in 2023. In addition, dengue incidence started even during the winter season and is steadily rising over the next few weeks. According to a mathematical modelling projection conducted by WHO (2022), the projection shows that cases have already exceeded the alert threshold since the beginning of 2023 when compared to the reported dengue cases in EWARS, indicating early signs of an outbreak in Nepal. The projection also estimated the incidence of around 3,500 to 4,000 dengue cases by September 2023, which will be the highest peak of dengue incidence for 2023. On average, 20 to 30 cases of dengue have been found each week in different regions of Nepal.
Since dengue is relatively new in Nepal, there is a low level of knowledge and awareness among people. Although dengue prevention was less of a priority in the country until last year, GoN has been sincerely trying to address the emerging trend through joint planning and implementation this year. The number of dengue cases reached its highest level in 2022, and the NRCS has carried out preventive measures only after the government declared an outbreak. However, the timeliness of the response was not optimal, as most of the hospital capacities were overwhelmed and the morbidity/mortality rate increased significantly. In addition, community-level preventive (search and destroy) campaigns were carried out during that period. But it was challenging to control mosquito breeding at that time. Therefore, NRCS has planned to carry out the early action activities before the outbreak is declared this year.
Dengue is endemic in Nepal. All four serotypes of dengue exist in the country, with DENV 1&2 contributing to the highest burden, according to EDCD, MoHP. In 2022, the country experienced a dengue outbreak with a total of 55,000 cases and 88 fatalities, which is one of the largest outbreaks in Nepal in terms of the cumulative number of cases reported nationwide per year. In 2023, Nepal has been witnessing sporadic cases of dengue even during the winter in almost all topographical regions of the country.
Dengue has disparate effects on different population strata. While pregnant and lactating women, children, and the elderly population are vulnerable to dengue, the young adult population working outside has a higher exposure risk to dengue-infected vectors. In addition, the urban design of major cities in Nepal lacks infrastructural public health aspects, along with a challenging waste management system and poor sanitation facilities, providing vectors with an optimal environment for breeding. People residing in slums or urban cities with poor sanitation facilities are at greater risk of being affected. Hence, an exponential rise in dengue cases can not only overwhelm health systems but also affect the most vulnerable population with low socio-economic conditions.