Type 11 dengue virus deadlier than previous types | Sunday Observer

Type 11 dengue virus deadlier than previous types

Patients with suspected symptoms should get examined by a qualified doctor within 2 days from onset of fever

While Dengue is not a new disease in Sri Lanka, doctors currently battling to save lives of affected patients have discovered that the prevailing Type 11 dengue is more virulent and can rapidly cause patients to develop the very serious complications of Dengue Haemorrhagic Fever and Dengue Shock Syndrome . Scattered rains followed by bursts of sunshine has also led to a proliferation of mosquitoes islandwide, with the number of patients tripling this year compared to previous years. The extreme heat has also further facilitated the hatching of larvae eggs .

Most hospitals have complained of being overwhelmed by the number of dengue patients, causing a serious problem of where to accommodate them, as the beds in even the biggest hospitals in Colombo, the National Hospital, Colombo, the IDH and Negombo Base Hospital, are now running short of beds as patients crowd into corridors or share beds .

The Sunday Observer spoke to Community Consultant Physician Dengue Control Unit, Dr Preshilla Samaraweera to find out more about the emerging dengue virus and its impacts on the human body.


Q. We are now in the throes of a full blown dengue epidemic. Many experts have blamed the unusual surge in dengue fever cases this year to changing weather patterns, from scattered rains followed by sunshine, proliferation of breeding sites, intense heat causing the larvae to hatch quickly, uncleared garbage, and the attitude of people on eco friendly environments.

Do you agree?

A. All these factors are responsible. Firstly, the change in the virus into type 11 which we are now experiencing. Secondly, uncleared garbage, and thirdly, drastic weather pattern changes from intense cold to intense heat, as well as scattered rains followed by short spells of sunshine where the larvae finds new breeding places. The intense heat also facilitates the hatching of the larvae according to recent research.

Q. What are the most common strains of dengue we usually see in Sri Lanka?

A. From 2009-16 , it was Type 1 and 4. From mid 2016 it shifted to type 11.

Q. How did it enter our country?

A. From travellers who have visited countries where this particular strain is currently circulating.

Q. Mention a few.

A. Singapore, Malaysia , India.

Q. Does that mean people who are not exposed to this virus are less able to fight it?

A. Yes. Because they still have not developed sufficient immunity against the disease.

Q. Is it more dangerous compared to previous strains we have seen? In what sense? ( explain in detail)

A. It is more virulent when a person is first exposed to type 1 and type 11, afterwards.

Q. Then what happens?

A. They become more prone to Dengue Haemorrhagic Fever ( DHF) which if not treated quickly could be fatal.

They will develop life long immunity against type 1 but since type 11 is new and they have never been exposed to it, they would not have developed immunity against it.

Q. Compared to the normal Dengue Fever, what is the difference? How would you detect if the patient has DF or this new strain of type 2 virus? What are the symptoms of 1) DF 2) type 2 dengue

A. There is no difference. But, more are getting it. Symptoms of Type 11 is a rapid drop in the platelet count. Other symptoms such as, fever, lethargy, pain are symptoms of all dengue fever cases. Theoretically, you can get Dengue Fever four times.

Q. So how do you know if it is Type 11 dengue?

A. With a full blood count.

Q. What about the Rapid Dengue Antigen Test ( NSI)?

A. Rapid Antigen tests only indicate that the person is infected with the virus. That’s why we ask for a full blood count.

It is advisable to get a full Blood Count and the Dengue Antigen Test done together and the medical practitioner to evaluate him,/her for signs of the disease. To differentiate the types we have to do a test called RtPTR with a full blood count and Antigen Test to confirm if the patient has dengue fever or dengue haemorrhagic fever.

Q. Who is most at risk?

A. It affects all ages. But, one needs to be more vigilant where infants and pregnant women are concerned. Elders too are more prone to get complications of the disease. Those who have undergone surgeries, people with suppressed immunity and those with chronic non communicable diseases like diabetes, chronic obstructive airways disease, heart, liver, kidney and metabolic diseases, should seek medical treatment within 24 hours.

Q. I understand this new strain is more virulent and faster acting than the previous strains and the risks of going into DHF and DSS are much faster and greater? Do you agree?

A. Previously, we used to request doctors to do a full Blood Count test in the first three days of the onset of the fever. Now, we have asked that a full Blood Count be done on the second day, because some patients can go into Dengue Haemorrhagic Fever quickly .

Q. What are the organs that are affected?

A. All. Because of the virulent nature of this new type 11, it is best to get treatment quickly with a Full Blood Count to see how much the platelet level has dropped.

Q. Is Dengue Fever and DHF curable? What is the treatment?

A. Both are curable. We usually give patients symptomatic treatment.

Q. Is there a drug to prevent Dengue?

A. Not yet.

Q. Once you get dengue can you get it again? Can it come back in a more virulent form?

A. As I said, you get life long immunity against the type you have already been affected with. Theoretically, you can get dengue fever 4 times.

Q. What is the National Dengue Prevention Campaign doing to prevent and contain the spread of the disease?

A. We have devised three objectives : 1) To reduce mortality from dengue 2) Reduce morbidity 3 ) Eliminate mosquito breeding sites. We have also distributed posters to raise more awareness on prevention and what steps to be taken if one suspects they have symptoms of the disease.

Q. Do you recommend home remedies for dengue patients? What about papaya juice and other alternative treatments which are being advocated by some?

A. Not only are they dangerous they can compound the disease in patients . We only use scientifically proved methods.

Q. What about pain killers and other drugs to reduce fever and pain?

A. Medications to avoid are aspirin and Non steroidal anti Inflammatory Drugs ( NSAID) like Ibupeofen, dicloferen etc. All those with dengue fever symptoms must only be given paracetamol according to doctor’s prescriptions and the age of the patient. If not, complications can arise and doctors can be confused with regard to the actual signs.

Q. Your golden rules on preventing dengue, DHF and DSS?

A. Clean. Clean. Clean. A clean environment both inside your home, garden and the neighbourhood, as it is essentially a neighbourhood disease since the mosquito carrying dengue can fly only 50 -200 metres.

Allowing used plastic lunch sheets, styrofoam boxes, empty yoghurt cups and other non degradable items like used tyres, unclean gutters that lie uncleared in school compounds or houses can only increase the breeding sites for the aedes egypti mosquito. So, regular cleaning is essential and it is the duty of all to join in this effort.

The female adult mosquito which bites is mostly visible and active in the early hours of the morning and late evening.

We have therefore advised people to wear long sleeved or fully covered dresses during daytime, apply mosquito repellents, screen their windows and doors to prevent the entry of the mosquitoes, and keep their kitchens, bedrooms and toilets well ventilated so that the mosquitoes can’t hide in dark places in the house.

The public must be accountable for their actions and be more careful about the cleanliness of their environment.