At present, Delhi is witnessing a rise in Dengue patients, reporting the maximum number of cases since 2018 due to prolonged monsoon. SUPRIYA RAMESH talks to experts to know more

According to the World Health Organization (WHO), Dengue cases have grown dramatically around the world in recent decades. A vast majority of cases are asymptomatic or mild and self-managed, and hence the actual numbers of Dengue cases are under-reported. Many cases are also misdiagnosed as other febrile illnesses.

With the advent of the rainy season, we surely get some respite from the scorching summer heat but many water-borne diseases tag along. And one of the most common diseases is Dengue, a mosquito-borne viral infection that is common in warm, tropical climates. It is caused by any one of four closely related antigenically distinct groups called serotypes that are DENV-1, DENV-2, DENV-3 and DENV-4, which means that it is possible to be infected four times in a lifetime. A particular serotype can be predominant at different times in a geographical area. It gives space to a wide number of symptoms that can be extremely mild (unnoticeable) to extremely severe. In severe cases, it can also be fatal.

Currently, Delhi is witnessing a surge in cases, reporting the maximum number of cases since 2018 for the same period due to prolonged monsoon. Whereas Punjab which observed 8,400 cases last year has reported only 5,889 cases this year, Hoshiarpur topping the list with 933 cases.

While many Dengue infections cause only mild illness, there have been cases where it has also caused an acute flu-like illness. Over time, this forms into a potentially lethal complication, called severe Dengue.  WHO states that severe Dengue is a leading cause of serious illness and death in some Asian and Latin American countries and requires management by medical professionals.

As per a comparative study published in Clinical Infectious Diseases, the incidence of Dengue has grown dramatically around the world in recent decades. A vast majority of cases are asymptomatic or mild and self-managed, and hence the actual numbers of Dengue cases are under-reported. Many cases are also misdiagnosed as other febrile illnesses.

The number of Dengue cases reported to WHO increased eight times over the last two decades, from 505,430 cases in 2000 to over 2.4 million in 2010, and 5.2 million in 2019. Reported deaths between the years 2000 and 2015 increased from 960 to 4032.

But why are we talking about DENV-2 at the moment? Is it more severe than all other serotypes? How worried should we be? These are the questions our mind is flooded with and it is high time we all should understand the seriousness of the disease and keep an ear to the ground.

The DENV-2 or D2 variant of Dengue was struck many cases of fever and deaths in western UP districts of Firozabad, Agra, Mathura and Aligarh. The term severe Dengue is in circulation now. It was earlier known as Dengue haemorrhagic fever and Dengue shock syndrome.

The new variant has been observed in 11 states and has become a topic of discussion amongst medical experts and organisations. “With DENV-2 type there seems to be a higher incidence of Dengue hemorrhagic fever where there is a capillary leak and bleed with low platelets and it may eventually progress to Dengue shock syndrome where blood pressure drops,” Dr Dilip Gude, Sr Consultant Physician, Yashoda Hospitals Hyderabad tells you.

“A person previously infected with Dengue when gets infected with a different serotype has a higher chance of developing hemorrhagic fever or shock syndrome,” tells Dr Anurag Aggarwal, Consultant Internal Medicine, QRG Super Speciality Hospital.

With all the talk about mosquitoes increasing during the rainy season, it is equally important to know that mosquitoes are also mainly attracted to carbon dioxide and heat, which indicates that they are equally active during summer. Moreover, DENV has the potential to infect people all year round and with this, the risk and fear remain throughout. Dr Anurag tells you more about the factors responsible for mosquito-spread. “Lack of adequate drainage, open drains and open areas of water stagnation are factors responsible for rapid spread. Increased movement of people without the adequate coverage of the body with exposed arms and legs increases their risk of getting bitten by an infected mosquito, wherein one in four people infected with Dengue virus will develop the disease.”

Talking about the symptoms, they can develop four to 10 days after the mosquito bites and last anywhere from two to seven days. We might be aware of only the common, usually talked about symptoms like high fever, severe body pain and internal bleeding with falling platelets but Dr Aggarwal gives a detailed note on the same. “High-grade fever with chills, backache, abdominal pain, rash, vomiting, joint pains, muscle aches, generalised weakness and fatigue and in severe cases shock, hemorrhagic manifestation like vomiting out blood, bleeding from anus, nose, gums and blood in the urine.”

He further adds that when a patient is having severe abdominal pain, recurrent vomiting and increased irritability, it may indicate the patient is developing severe Dengue. The intensity of fever has no correlation with the severity of illness a patient develops in the following days of illness.

In case one is facing possible symptoms and is sceptical about the testing, all you need to know is that there are two ways to get yourself tested, a card test and ELISA. Dr Aggarwal elaborates, “Testing is done by blood. One is through the card test which is not as sensitive as another test called ELISA. Two types of antigens are of significance, NS1 which is usually detectable within 24 hrs of symptom onset and may remain positive until nine days and other is IgM which is usually detectable four to five days after symptom onset and remains positive up to 12 weeks after catching an infection or maybe even longer.”

More than 20,000 confirmed Dengue cases across the country have been reported with more than 220 deaths occurring only in Uttar Pradesh. Cases have been reported from Andhra Pradesh, Gujarat, Karnataka, Kerala, MP, Uttar Pradesh, Maharashtra, Odisha, Rajasthan, Tamil Nadu, and Telangana.

There are no vaccines and currently, the treatment of Dengue is through supportive care and no specific medication is available. “The management includes intravenous fluid therapy, monitoring of the clinical condition, and intensive care. This helps reduce the morbidity and mortality in Dengue fever complications. Mild and uncomplicated cases can be managed at home under the supervision of the doctor,” Dr Anjali Saxena, Senior Consultant, General Pediatrics tells you.

Moreover, WHO has advised that patients should seek medical advice, rest and drink plenty of fluids. Paracetamol can be taken to bring down fever and reduce joint pains. However, aspirin or ibuprofen should not be taken since they can increase the risk of bleeding.

We can say that the Dengue outbreak is still under control but it has led to a surge in cases of high fever countrywide. As it is known to cause more morbidity than other variants, patients are having high-grade fever. Dr Gude tells you that there is an epidemiological hypothesis that there is a four-year cyclical spurt for Dengue outbursts and DENV-2 serotype now is known to cause a much-complicated disease.

With this, he advises that early diagnosis, aggressive hydration, and admitting high-risk groups such as the elderly and children and immunosuppressed patients may be important.

Considering the pandemic, how worried should we be about the Dengue virus? Are there chances that it could worsen amidst the pandemic? These are again a few questions that might cross our minds. Early symptoms of both COVID and Dengue can be the same and it would be nearly impossible for a common man to self detect if he/she has been infected by corona or Dengue. And coinfections are common and if someone gets COVID and Dengue then the outcome is going to be deadly.

“In this pandemic background, one needs to be extra careful and take all necessary precautions to prevent mosquito-borne diseases,” Dr Gude tells you.

Dr Saxena tells you that during these times healthcare resources can get overwhelmed and this can be detrimental to providing medical care to the needy.

Your safety is in your hands and making sure that you are not giving a breeding ground to mosquitoes is your responsibility.  Keep the surroundings of your house as dry as possible with no scope for stagnant water, cover your body with full sleeves clothes, put on mosquito repellent creams, coils, nets. Dr Gude suggests that having a high index of suspicion and taking a clinician's help as early as possible is important.

“Do not allow water to stagnate, cover drains or sprinkle oil over stagnated water, empty pots/tyres of water in your house, wear full sleeves clothes when stepping outside the house,” Dr Aggarwal tells you.

He further adds that in case of fever, visit your nearest physician as soon as possible. Watch for symptoms like intense abdominal pain, bleeding from any site, restlessness and breathlessness when you need to be concerned.

“The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for Dengue as well as for other diseases that Aedes mosquito transmit. At present, the main method to control or prevent the transmission of Dengue virus is to combat the mosquito vectors,” WHO advises and suggest ways through which it can be achieved.

• Prevention of mosquito breeding

Preventing mosquitoes from accessing egg-laying habitats by environmental management and modification

Applying appropriate insecticides to water storage outdoor containers

• Personal protection from mosquito bites

Using of personal household protection measures, such as window screens, repellents, insecticide-treated materials, coils and vaporizer and wearing clothing that minimises skin exposure

• Community engagement

Educating the community on the risks of mosquito-borne diseases

• Reactive vector control

Emergency vector control measures such as applying insecticides as space spraying during outbreaks may be used by health authorities

In addition, there is ongoing research amongst many groups of international collaborators in search of novel tools and innovative strategies that will contribute to global efforts to interrupt the transmission of Dengue, as well as other mosquito-borne diseases.