Dengue alarm: Huge concern

With dengue season approaching, the government should be extra vigilant about dengue outbreak anywhere, particularly in the flood affected areas, and be better prepared for future outbreaks

Dengue, one of the emerging vector-borne diseases of Nepal, is being increasingly detected among suspected febrile patients in Kathmandu. As of 1st September, at least 34 dengue cases have been detected by laboratory testing at Sukraraj Tropical and Infectious Disease Hospital (STIDH). Majority of these patients are now under treatment in different hospitals in Kathmandu. It indicates that dengue, a comparatively new viral disease, is appearing in an alarming manner in Kathmandu, and perhaps even in other parts of the country. In fact, more than 40 dengue patients’ from Lalbandi, Sarlahi district, have been treated at STIDH over the past two weeks, while several others are under clinical observation, meaning there is currently an ongoing outbreak of dengue fever in Sarlahi district. Dengue increases its activity between September-November in Nepal.

Recently, Sri Lanka has faced an unprecedented outbreak of dengue, with nearly 300 deaths and over 100,000 cases recorded in 2017, which is, according to the WHO, 4.3 fold higher than the average number of cases for the same period 2010 and 2016. Dengue virus serotype-2 was found responsible for this Sri Lankan outbreak. Dengue virus has four serotypes namely, DEN-1, DEN-2, DEN-3 and DEN-4. All four serotypes have been known to be co-circulating in Sri Lanka for more than 30 years. Similarly, in Nepal, all four serotypes have been found to be co-circulating since 2006. The first major dengue outbreak occurred in 2010 in Nepal. Since then, no such major dengue outbreaks have been recorded in Nepal. Several scientific reports have documented that major outbreaks of dengue usually occur every three to five years. A large dengue outbreak in Nepal, therefore, is expected or inevitable anytime in the future. We will be unable to bring outbreaks under control within a relatively short period of time as the country lacks adequate infectious disease specialists, dengue awareness, strong surveillance networks, infectious disease hospitals with modern and improved facilities, state-of-the-art laboratory, and most importantly political or government commitment towards infectious diseases.

Fever, headache, pain behind the eyes, muscle pain, rashes, and severe joint pains are the chief complaints of the patient with dengue fever. Because of extreme joint pains and body ache, it was formerly known as “break-bone fever”. If left untreated, it can cause bleeding known as “dengue hemorrhagic fever”, shock or even death. Bleeding from nose or gums, vomiting blood, black stools, red-purple dots or patches under the skin are some of the major signs of dengue hemorrhagic fever, and if these signs are associated with abdominal pain and persistent vomiting, it is regarded as “Warning Signs”. In Nepal, my previous research showed that nearly 10% of the dengue patients had developed “dengue hemorrhagic fever” and or “Warning Signs.” Similar results have also been demonstrated by other studies in Nepal. Usually bleeding problems occur as a result of secondary infection. Secondary infection is when an individual becomes infected for the second time. Secondary infection with a different serotype greatly increases the risk of bleeding in individuals. Since 2004, we have been experiencing multiple serotypes of dengue virus every year, meaning the chance of acquiring secondary dengue infection can be expected to increase greatly in the coming years. However, little information is available or restricted among researchers about distribution of serotypes in Nepal. PCR can help identify serotypes of dengue virus. Nevertheless, this method is expensive and not widely available in Nepal.

An alarming increase in the mosquito population that carries dengue viruses, known as aedes agypti and aedes albopictus, is another huge concern for Nepal. They both look similar with black and white stripes on their bodies and legs and they are day bitters. Last year, the Epidemiology and Disease Control Division (EDCD) warned of a dengue epidemic in Kathmandu city, and has, then planed an ‘Operation’ “ Mosquito Search and Destroy” campaign because both aedes mosquitoes have been found widely distributed in Kathmandu valley. A research carried out in Kathmandu has demonstrated that high frequencies of aedes mosquitoes are more commonly found in discarded tires followed by metal/plastic drums and plastic buckets. The number of vehicles is increasing year by year, while old/waste tires are usually thrown onto the streets which poses serious threats of dengue epidemic in the coming days. Municipalities of the Kathmandu should strictly monitor this issue, because “Mosquito Search and Destroy” campaign initiated by EDCD alone cannot ensure control and prevention of dengue epidemic effectively and efficiently.

With dengue season approaching, the government should be extra vigilant about dengue outbreak anywhere, particularly in the flood affected areas, and be better prepared for future outbreaks. For this, we need our own dengue guidelines first for diagnosis, treatment, prevention and control based on our own experiences and available resources that would greatly assist health care providers in minimizing dengue complications and controlling an outbreak if it occurs.

Pun is Coordinator, Clinical Research Unit, Sukraraj Tropical and Infectious Disease Hospital