Another Monsoon, Another Dengue Surge: Why Does This Repeat Every Year?

Parts of India are once again seeing a spread in dengue cases in clusters. Is this a cause for concern?

While Singapore's dengue outbreak has sent their government into overdrive, are India's dengue cases at risk of turning into an epidemic?

(Illustration: Chetan Bhakuni)

As Monsoon slowly recedes from most parts of India, like clockwork, infectious diseases like dengue and malaria have started moving in – thanks to water logging and the damp weather creating a prime breading ground for the mosquitoes that spread them.

This year, Delhi has already reported 1,258 dengue cases - the highest since 2018, according to a report by the Municipal Cooperation of Delhi. Over 300 of these cases were reported in the first five days of October alone.

Responding to the rising cases of vector borne diseases, all the hospitals in the National Capital have been asked by the government to reserve 10-15 percent beds for patients of vector-borne diseases, said Delhi Deputy Chief Minister Manish Sisodia, on Tuesday, 11 October.

Kolkata, on the other hand, has been seeing a surge in dengue cases everyday for the last few week with the city recording 2,800 cases of Dengue so far this year. On 10 October, 662 new cases were reported in the city.

In Patna, 1,844 dengue cases were reported till 8 October, according to the district administration. For comparison, in 2021, a total of 353 cases were reported in the city.

Uttrakhand's Haridwar district is also on high alert after a surge in cases, as well.

The real numbers, according health officials, are likely to be far higher.

FIT takes a closer look at what the situation is like in different parts of the country, and asks experts what this spike in cases means.

What Is the Dengue Situation Like in India Right Now?

“The last three to four weeks, we have been seeing a huge spike I would say," Dr Dibyendu Mukherjee, Consultant Internal Medicine, Fortis Hospital, Anandapur, Kolkata.

He goes on to add that nearly 60 percent of the patients admitted in the medical ward right now at his hospital are dengue patients.

Dr Mukherjee also reports that many of these patients have severe illness.

"These patients who are coming to the hospital are mostly severe cases. Their platelet count is dropping, some have got dengue shock syndrome as well. On occasion, we are seeing patients with fluid in the lungs. These are all complications of dengue ."

Dr Dibyendu Mukherjee, Consultant Internal Medicine, Fortis Hospital, Kolkata

Although, he adds, they haven't had any deaths in their hospital yet. "Death count is not so high because the platelets are not dropping below 10 thousand," he says.

Dr Laxman Jessani, Consultant, Infectious Disease Specialist, Apollo Hospitals Navi Mumbai, on the other hand says that although they are seeing more cases now than a few months ago, it isn't a worrisome situation.

However, Dr Jessani also adds that they too have been seeing patients with severe illness and complications.

“We are seeing some cases of dengue with complications - Dengue with ARDS (Acute respiratory distress syndrome) affecting the lungs, or dengue shock syndrome where the patient’s BP is very low, or dengue with secondary stepsis, or dengue with HLH (Hemophagocytic lymphohistiocytosis).

Dr Laxman Jessani, Consultant, Infectious Disease Specialist, Apollo Hospitals Navi Mumbai

"These cases there is high mortality associated with it. So we are seeing dengue deaths as well," he adds.

Speaking of the situation in Delhi, Dr Aditya Chawla, Senior Resident, Dr RML hospital says that although there has been a spike in cases, "Most of the cases are mild cases."

Dr Suneet Kumar Verma, Senior consultant - Internal Medicine, Alchemist Hospital, Panchkula, on the other hand, tells FIT that although there is a spike in cases this year, it is still lower than last year.

“I am dealing with Dengue for the last 14 years now in this zone and have never come across the kind of mortality rate that we saw last year.”

Dr Suneet Kumar Verma, Senior consultant - Internal Medicine , Alchemist Hospital, Panchkula

That said, he adds that the surge in cases in the district, particularly in the Kalka-Pinjore area has got authorities concerned.

Is This Spike a Cause for Concern, or a Yearly Occurrence?

This spike in dengue cases in the country is not unusual say experts.

"Last few years we have seen a spike in dengue cases around this time - Just after the monsoons. So, it is not unique this year," says Dr Mukherjee.

“We see cases every year and its very typical. It is typical in this post-monsoon months," adds Dr Jessani.

Speaking to FIT for a previous article, Epidemiologist J P Muliyil explained that dengue is endemic in India.

This means that periodic spikes in cases are to be expected. In India, this spike usually happens in the post-monsoon months of September and October.

However, this doesn't mean we become complacent.

"The most striking thing about dengue this time is that unlike last times, we are seeing a drop in the white blood cells count," says Dr Mukherjee.

"That is something unique from the last two years, because if the WBC count drops they become susceptible to other infections too."

Dr Dibyendu Mukherjee, Consultant Internal Medicine, Fortis Hospital, Kolkata

This could have been because of a new strain, he says.

There are, basically, four different types of dengue virus.

"DENV-1 infections may be more severe compared with DENV-2 infection. DENV-1 cases were more likely to present with red eyes whereas the absence of red eyes but presence of joint pain and lower platelet count was associated with DENV-2 cases."

Dr JP Muliyil, epidemiologist, to FIT

"When you have the first infection, you don't have any antibodies so you'll recover mostly and you'll feel fine. But in some cases of reinfection with another type of dengue in a year or two, the body tends to, in some cases, not all, react violently. It's a case of our immune system overreacting," he explains, adding, "this can be dangerous."

How to Protect Yourself

In preparation of an impending surge in cases in the city, the Delhi government, in the first week of October, chalked out an action plan to prevent mosquito breeding and dengue spread.

In the statement released by the Delhi Government, Sisodia said the present weather conditions are conducive for the transmission of vector-borne disease.

He warned that although the number of dengue cases has seen a sharp rise in the last two weeks, there is no need to panic, reported PTI.

“Some activities also have to be done by the municipal cooperation like fogging, preventing the breeding ground for mosquitos," says Dr Laxman Jessani.

On an individual level, these protective measures can help, particularly during the monsoons and in the post-monsoon months.

• Use mosquito nets

• Frequently apply mosquito repellent - particularly on your hands and feet

• Wear full sleeved clothes

• Make sure there is no stagnant water in potted plants in the house

• Be especially vigilant in the morning, because Dengue mosquitoes are known to bite early in the morning

Some other safety measures recommended by the World Health Organisation (WHO) are,

• Cover emptying and cleaning water storage containers on a weekly basis.

• Educate the community about prevention and safety measures.

• Seek medical help if you or someone close to you develops high fever (40°C/ 104°F) accompanied with headaches, pain behind eyes, nausea, swollen glands, joint, bone or muscle pains, or rashes on the body.

(Written with inputs from PTI)