The short heavy showers followed by bursts of sunshine we are currently experiencing has left pools of water on roads, lanes, gardens and even caused indoor leaks. These conditions are ideal as breeding sites for the dengue carrying mosquito resulting in the spread of Dengue fever leading to the more severe forms such as Dengue Haemorrhagic Fever (DHF).
However, Dengue can easily be prevented with proper precautions to keep mosquitoes at bay and clean surroundings, Dengue prevention authorities have said.
Unfortunately, this message seems to have fallen on deaf ears by many members of the public who only take measures to eliminate breeding sites by the public when there is a dengue outbreak. The focus on vaccinating people against the Covid-19 virus has also distracted the public from their routine efforts of cleaning their surroundings.
Due to concerns raised by heath authorities, The Sunday Observer spoke to Community Physician, Ministry of Health Dr. Ramya Premaratne to help educate readers on how Dengue is transmitted and how it spreads, how to protect ourselves and why it is so important to eliminate breeding receptacles and breeding sites that attract the dengue carrying vector.
Excerpts
Q: The current weather conditions in the country have prompted fears of an outbreak of dengue. Although most persons are familiar with the term Dengue, many still don’t know how it is transmitted and what causes it. Can you explain this to our readers?
A: The dengue virus spreads through a human-to-mosquito-to-human cycle of transmission. Typically, four days after being bit by an infected Aedes aegypti mosquito, a person will develop viremia, a condition in which there is a high level of the dengue virus in the blood. Viremia lasts for approximately five days, but can last as long as 12 days. On the first day of viremia, the person generally shows no symptoms of dengue. Five days after being bit by the infected mosquito, the person develops symptoms of dengue fever, which can last for a week or longer.
After a mosquito feeds on the blood of someone infected with the dengue virus, that mosquito becomes a dengue vector when the infected person has high levels of the dengue virus in the blood. Once the virus enters the mosquito’s system in the blood meal, the virus spreads through the mosquito’s body over a period of eight to 12 days. After this period, the infected mosquito can transmit the dengue virus to another person while feeding.
Q: What are the types of dengue circulating in Sri Lanka? Is there a difference in the types circulating now compared to previous years?
A: Aedes Aegypti and Aedes Albopictus are the vectors responsible for the transmission of dengue viruses (DENV). The four DENV serotypes (1, 2, 3, and 4) have been co-circulating in Sri Lanka for over 30 years.
The new genotype of DENV-1 has replaced an old genotype, and new clades of DENV-3 genotype III have replaced older clades. The emergence of new clades of DENV-3 in the recent past coincided with an abrupt increase in the number of dengue fever (DF)/dengue haemorrhagic fever (DHF) cases, implicating this serotype in severe epidemics.
Q: How can you tell the difference between a common flu and dengue fever as both have similar symptoms at the start? Or does it have different phases of development? If so what are they?
A: In typical viral infection, one may have a runny nose, throat pain, mild body ache and weakness. In dengue, the person may have a high-grade fever, severe body ache, severe joint pains and rashes (pinkish in colour) all over the body within 24 to 48 hours of the fever, Severe headaches, Pain behind the eyes, muscle pain, Fatigue, Nausea, Vomiting, Mild bleeding (such a nose bleed, bleeding gums, or easy bruising are other symptoms of Dengue fever.
To differentiate between viral fever and dengue fever, the patient is advised to undergo a full blood count test along with a dengue NS1 antigen test.
Dengue is most common in during the monsoon season. May- August and October- January. Viral fever, on the other hand, can occur during the transition period of any two seasons.
Q: Warning signs and symptoms to look out for?
A: Belly (Abdominal) pain, tenderness, vomiting (at least three times in 24 hours)
Bleeding from the nose or gums. Vomiting blood, or blood in the stool. Feeling tired, restless, or irritable
Q: Can they be treated at home? How?
A: There is no medicine to treat dengue. Symptoms of dengue can be mild or severe. Dengue with Mild symptoms can be treated at home. Rest as much as possible. Control fever.
Give Paracetamol to control fever. Do not give ibuprofen, aspirin, or aspirin-containing drugs. Sponge the person’s skin with cool water to reduce fever. Prevent dehydration – Dehydration occurs when a person loses too much body fluid from fever, vomiting, or not drinking enough liquids.
Q: Signs of severe dehydration?
A: In babies and children, look out for: sleepiness, lack of energy, sunken eyes, cool, discoloured hands or feet, Reduced Urination 1-2 times a day. In Adults, symptoms include: dark yellow urine, dizziness, sleepiness, becoming confused or irritable, rapid heartbeat, breathing problems and sunken eyes.
Q: What happen if pregnant mothers get infected? Can she pass the virus to her foetus?
A: A pregnant woman already infected with dengue can pass the virus to her fetus during pregnancy or around the time of birth. Dengue can have harmful effects, including death of the foetus, low birth weight and premature birth. Dengue virus infection during pregnancy increases the risk for any neurologic congenital anomaly in the infant by roughly 50 percent and for other congenital malformations of brain 4-fold.
Q: What is the most severe form of Dengue?
A: The most severe form of Dengue is severe Dengue Haemorrhagic fever and Dengue Shock Syndrome, where patients develop plasma leakage, bleeding, respiratory distress and internal organ dysfunction, particularly in the liver, heart and central nervous system. Patients go on to develop a severe and sometimes fatal form of the disease around the time the fever begins to subside (usually 3–7 days after symptom onset). The patient may develop warning signs of severe disease also called dengue haemorrhagic fever that can cause serious bleeding, a sudden drop in blood pressure (shock) and death.
Q: So when do they need to be hospitalised?
A: The indications for hospital admission include the following conditions:
Abdominal pain, Persistent vomiting, Fluid accumulation, Mucosal bleeding, Lethargy, weakness.
Patients with dengue symptoms and warning signs should be admitted to hospital for appropriate monitoring, treatment and eventual reference to an intensive care unit (ICU) in case of medical/laboratory worsening.
Due to the potential worsening of pre-existing conditions, people under 15 or above 60 years old, pregnant women and patients with underlying conditions, such as obesity, diabetes mellitus, severe cardiovascular disease, asthma and chronic obstructive pulmonary disease (COPD), blood diseases, chronic renal failure, and immunosuppressive drugs, deserve special attention.
Q: What are the tests required to confirm if a patient has dengue?
A: Full Blood count
Dengue NS1 Antigen. This is a blood test to detect the dengue virus early in the course of an infection.
Immunoglobulin M (IgM) (Antibodies)
Immunoglobulin G (IgG) (Antibodies)
Q: What are the current methods used to eliminate breeding sites?
A: · Space spraying of insecticides
· Source reduction by removing mosquito breeding containers and tyres
· Environmental Control to eliminate the breeding by altering the environment to make it unfavourable for mosquitoes to breed.
The dengue-spreading mosquito is a day-biting mosquito that is most active for around two hours after sunrise and several hours before sunset but it also bites at night in well-lit areas.
Q: What is the best approach to control the spread of dengue?
A: Protect yourself against mosquito bites. Prevent mosquito breeding inside and outside your home by getting rid of all water collecting receptacles both inside and outside the house. . Avoid visiting areas prone to mosquitoes.
Q: Challenges facing those engaged in trying to eliminate breeding sites?
A: Although awareness on dengue prevention is universal, various challenges still remain unanswered. Inadequate funding, limited resources hamper the dengue prevention, particularly in the villages and some suburban areas. The lack of an implementable and sustainable strategy to respond to the problem in an expanding geography of dengue worsens problems faced by the authorities despite the many efforts made in the past.
Q: Is there a contact number or a hotline to alert people about dengue?
A: The National Dengue Control Unit in the Ministry of Health, Nutrition and Indigenous Medicine Public Health Complex 555/5, Elvitigala Mawatha, Narahenpita Colombo 5.
Tele: 011-2368416, 011-2368417
Fax: 011-2369893
E-mail: [email protected]
Web: www.dengue.health.gov.lk