Dengue in Kathmandu

The ongoing monsoon, and the circulation of other infectious diseases that come with it, may lead physicians to misdiagnose or be unable to identify or manage dengue appropriately and in a timely manner

Over the past few days, a growing number of patients are being diagnosed with dengue virus infection in Kathmandu, despite having never travelled outside the city in those few days.

A press meet organised by the Epidemiology and Disease Control Division informed that at least 60 patients with dengue virus have been confirmed in Kathmandu. The number of cases that have been reported up until now is far higher compared to the previous year. Dengue in Nepal is mostly reported during October through December, which may indicate the possibility of a larger dengue outbreak in the Kathmandu Valley.

So far, nearly 4,000 dengue cases have been identified since the beginning of the outbreak of 2019. Dengue fever is usually mild and subsides in about 7 to 10 days after the symptoms first appear. My recent published research suggests that only 10 per cent of dengue-infected patients might develop a critical phase. So, most patients do not require hospitalisation, only close supervision of a doctor, complete rest and plenty of fluids.

However, many are unaware of the dos and don’ts while getting bed rest at home after infection. People may have heard of dengue virus, but they lack adequate knowledge regarding its nature or behaviours. Indeed, so far, there have not been any publicly known campaigns against this virus other than “mosquito search and destroy” in Kathmandu, even though the aedes mosquito, which carries the dengue virus, has been in the valley for a long period of time.

Currently, the government is requesting the public not to use dengue kits for all suspected cases due to its acute shortage. We are still underestimating the possible spread of dengue virus, despite regular outbreaks since 2010. It is almost certain that dengue virus will be more widespread over the next decades on account of the easy access of transportation, rapid urbanisation, ineffective mosquito control, lack of political commitment, climate change, increase in the surveillance and lack of knowledge.

The ongoing monsoon, and the circulation of other infectious diseases that come with it, may lead physicians to misdiagnose or be unable to identify or manage dengue appropriately and in a timely manner. At present, hundreds of dengue patients have presumably gone underreported, or are being treated for other infectious diseases due to lack of dengue testing kits.

Thus, the government must store sufficient number of dengue kits before the dengue season arrives. Dengue was first detected in Kathmandu during the 2010 outbreak across Nepal. Smaller dengue outbreaks have occurred since then. However, mosquitoes that carry the dengue virus were found to be widespread across Kathmandu during the 2011 survey (done by EDCD), indicating that a large-scale outbreak could have occurred in Kathmandu at anytime.

Moreover, dengue spreads more rapidly in larger cities with a more concentrated population, meaning that Kathmandu (the biggest and most densely populated city in Nepal) has always been at risk of dengue outbreaks in the past, which remains the same for the future.

The outbreak in Kathmandu is quite unusual and interesting. Outbreaks usually occur in clusters, but, in contrast, patients with dengue virus visiting the Sukraraj Tropical and Infectious Disease Hospital (STIDH) are from different places (scattered) across Kathmandu. This indicates that mosquitoes, possibly carrying the dengue virus, are now active across the various areas of Kathmandu. It can also be assumed that mosquitoes are moving freely and easily from one place to another due to increased vehicular movements. Another interesting point about this outbreak is the appearance of atypical symptoms, such as sore throat and transient hearing problems (or tinnitus) among confirmed dengue cases. It is also known as expanded dengue syndrome (EDS), which has been increasingly reported in recent years.

Precautionary measures in Nepal are impractical and need to be modified based on our available resources and infrastructure. For example, the government is advising the public not to collect and store water for a longer period of time inside and outside of their houses. However, this seems highly unfeasible unless the government addresses the water demand efficiently. Furthermore, following the current dengue outbreak, the concerned bodies have initiated “mosquito search and destroy” programmes aiming to control the outbreaks. But the federal government doesn’t have enough staff, and even sufficient logistic or financial support for such door-to-door efforts across the country.

The fact of the matter is that mosquitoes have never been successfully eliminated with the “mosquito search and destroy programme” in the past. In addition to this, it is now clear that the local governments are not prepared for any outbreaks and have failed to coordinate among the concerned bodies. This issue, however, must be taken as a lesson to develop control strategies accordingly, so that similar large outbreaks can be controlled as early as possible in the coming days.

The present dengue outbreak is the longest in duration, largest in terms of cases and most devastation in Nepali history, one that is unfortunately still spreading aggressively in Kathmandu and across the country.

Dr Pun is Chief, Clinical Research Unit, STIDH