Health authorities have recently reported rising dengue fever cases nationwide in Sri Lanka with more than 33,000 suspected cases reported between January 1 - May 14. Media reports have quoted Health Ministry officials as saying that an epidemic was imminent unless the nation as a whole acts fast to halt this disturbing trend. Epidemiologists have also warned that the risk of dengue is highest in the next few months from May - July and again in October to January. Hence they have urged the public to take adequate precautions to safeguard themselves especially if they live in regions which are at high risk of flooding, landslides and heavy rains followed by short bursts of sunshine which are ideal for the dengue-carrying vector to lay its larvae.
As young children are mostly at the highest risk of contracting dengue as well as being exposed to the adverse impacts of complications from the more serious forms of dengue, namely Dengue Haemorrhagic Fever (DHF) and Dengue shock Syndrome ( DSS,) the Sunday Observer spoke to Consultant Paediatrician, Sri Jayewardenepura General Hospital, Dr. Mihira Manamperi who has also done several research studies on the impact of dengue on children, to share some of his expertise with our readers.
Excerpts
Q: Although many of our readers are familiar with the term Dengue, many of them are still ignorant of the seriousness of the diseases especially in the case of young children . For their benefit could you tell us what the symptoms of Dengue are ? What are the clinical signs to look out for that distinguish dengue from DHF? Are there different stages in its progress?
 Dr. Mihira Manamperi |
A. There are three main distinguishing features in Dengue. Undifferentiated febrile illness, Dengue Fever (DF) and more severe Dengue Haemorrhagic Fever (DHF). Undifferentiated febrile illness is the mildest form and it is more or less resembling another viral illness. During the first few days dengue fever and dengue hemorrhagic fever cannot be differentiated from each other. In both of these clinical entities children can have very high fever up to 104ºF and it will show a very poor response to paracetamol. They also will have retro-orbital (behind the eyes) headache, severe body aches, muscle, joint and bone pain. Some also will have symptoms such as throat pain, cough, and coryzal symptoms.
They could also have bleeding manifestations such as gum bleeding and passing red blood cells with urine (haematuria). Dengue fever will have two phases, febrile phase and a convalescent phase. In contrast, DHF will have a maximum period of up to 48 hours of plasma leakage before entering into the convalescent period. It could also lead to concealed haemorrhages. It is often difficult to differentiate DF from DHF in the febrile phase of the illness. Therefore, suspected DF and DHF patients should be closely followed up to detect evidence of plasma leakage.
Q: How do you diagnose that a patient has dengue?
A. If the patient is from a dengue prevalent area, with a close contact of the neighbouring vicinity, one should suspect dengue infection. Then a full blood count (FBC) with the NS1 antigen test together with the symptoms will help to diagnose it.
Q: What are the tests that need to be done to confirm the patient has dengue?
A. NS1 antigen test is a useful test to diagnose dengue infection early. When it is available it should be performed in the first three days of the illness. However, it will not help to predict DHF. At the same time a negative test does not exclude the dengue infection. During the febrile phase FBC also gives some hints to a dengue infection. Low total white cell count with relatively low platelet count will always favour the diagnosis of dengue.
Q: What are the ideal times of the day for the dengue vector to take its blood bites on humans?
A. The vector for dengue, Aedes mosquito, bites during the day. The highest biting intensity is about two hours after sunrise and the evening before sunset.
Q: Who are those most vulnerable to getting a more complicated Infection? Children? Elderly?
A. Young infants, obese children, those who have taken Ibuprofen and Mefenamic acid as an antipyretic, those who have been prescribed dexamethasone, methylprednisolone and other steroid drugs, past history of Dengue and children with comorbidities such as diabetes, long term renal disorders. Elderly people are also susceptible for a more severe disease with their already existing comorbidities such as diabetes, hypertension and with a background of ischemic heart disease.
Q: As you are a paediatrician, tell us how Dengue Haemorrhagic fever impacts on young infants and to what degree they are at risk of contracting it?
A: Young infants are in the high risk category. They almost always are breast fed. They can enter the critical phase of DHF earlier than a bigger child. The plasma leakage could be for a brief period (less than 48 hours) and they could leak fast. Monitoring the vital signs as well as controlling the fluid intake is tough as the baby wishes to have breast milk a lot. The liver could easily get compromised in young infants and the bleeding tendencies are also higher in this group.
Q: Treatment -wise how do you treat an infant with suspicious symptoms of dengue?
A. They need early hospital admission for more meticulous monitoring. At times your doctor will advise the mother to control or even stop the breast feeding to get a better understanding about the intake. Sometimes they will pass a tube to the bladder to get a more precise calculation of the urine output or they will measure the dry and wet pamper weight.
Q: Is the treatment the same for older children like toddlers, primary school children and pre -adolescents? Or do they vary from age to age?
A. With increase in age the management of dengue is much easier. The amount of fluid intake and the urine output would be calculated according to the body weight. After two days of onset of fever Full blood count (FBC) should be done and if the platelet count is above 200×109/L, then the child should have at least FBC daily . Your doctor may even decide to do it more frequently. The latest recommendation is to admit the child if the platelet count is less than 150×109/L. The patient needs to go through a clinical review if the child deteriorates fast with symptoms such as severe abdominal pain, persistent vomiting, not passing urine for more than 6 hours.
Q: Can one have dengue fever more than once? If so will it affect the immunity levels of the person concerned ? What are the complications of getting regular attacks of dengue fever in the case of children?
A. There is a tendency to develop severe forms of dengue in subsequent infections. The partial immunity obtained by previous infection from a different serotype induces a stronger immune response from the host. This immune response could damage the tiny blood vessels and lead to more plasma leakage.
Q: Concurrently, we also have a viral flu outbreak due to the rainy weather. Since both appear to have similar symptoms at the onset, how can you tell the difference between a common flu and dengue fever?
A. As mentioned in the beginning it is very difficult to differentiate from each other. Even children with Influenza will have low platelet counts, sometimes even less than 150×109/L with low total white cell count. During the first three days NS1 antigen test may be helpful to differentiate those two. However if the platelet count shows a downward trend it is always advisable to manage it as dengue till your doctor gets a clear idea.
Q: Preventing exposure to dengue has been cited as the best way to minimise dengue risks .. Do you agree? If so, how can this be done? Give us some simple guidelines.
A. Yes. Preventing exposure must play a pivotal role in minimising risk of dengue in order to reduce the burden on the curative sector, reduce expenditure of treating dengue infection and save one’s family as well as the lives of neighbours. Following the guidelines listed in the Guidelines on Management of Dengue Fever and Dengue Haemorrhagic Fever in Children revised edition 2023 May and National Dengue Control Unit website should be helpful:
Eliminating dengue mosquito breeding places
1. Cleaning one’s drains, garden, roof (and within the home) once a week and eliminate artificial and natural (plants, tree holes, tree stumps etc.) sites of water collection
2. Cleaning outdoor and indoor premises of offices, schools, shops, tuition classes, places of worship, education institutes etc. once a week
3. Liaise harmoniously with Grama Niladhari, Public Health Inspector and Medical Officer of Health in your area and give them your full support and cooperation.
* Protect oneself and family members with personal protective measures like repellants, bed nets, long sleeved and long legged clothing when outdoors
* Fogging is a crucial preventive method during epidemics with a boom in cases. It eliminates the adult dengue mosquitoes.
* Treating breeding sites (where the site is large or elimination of breeding site is impractical or not possible) with larvicides i.e. construction sites, cement tanks, roof gutters and concrete slabs.
Q: Have you a message to give our readers, especially parents of young children on preventing and managing dengue?
A. As I mentioned earlier and reiterate again, infants and neonates (less than 28 day old babies) are at highest risk as they have very high death rates of they contract dengue.So it is extremely important, that if you live in a dengue prevalent area and your baby develops a fever that you consult your paediatrician early. The paediatrician will then arrange an NS1 antigen test to identify the dengue illness early. If the test becomes positive my advice is that you follow the advice given to you carefully. The paediatrician may suggest that you hospitalise the baby for more meticulous monitoring to ensure that the infant gets a smooth and complete recovery.
I also urge parents to refrain from using non-steroidal anti-inflammatory drugs (ibuprofen, mefenamic acid etc.) and steroids (prednisolone, dexamethasone and methylprednisolone) to bring down the fever.
Q: Since the months of June - July is considered a transmission period for Dengue in Sri Lanka and we are now experiencing weather conditions that promote ideal breeding grounds for the dengue carrying mosquito larvae, do you have any further advice to offer readers and others on how they could best avoid the risk of dengue exposure at this time around?
A. If you have previously been infected with dengue fever, consult your physician regarding vaccination. Avoid mosquito bites and remove standing water to reduce the number of biting mosquitoes. Seek medical attention if symptoms develop within two weeks of being in affected areas. Do not use aspirin or ibuprofen products if dengue fever is suspected, as these could exacerbate bleeding tendencies associated with the disease.