As part of our research, we conducted an interview with Dr. David Lye, an expert in dengue fever from Tan Tock Seng hospital (one of the primary hospitals in Singapore) on the fifteenth of February. This is the transcript of the interview.
The audio recording of the interview can be downloaded from this link.
[MP3 | 9MB | 37 minutes ]
How was the outbreak of dengue handled?
I think the answer is very well. If you look at the worst time in September October we had five to ten hundred cases a week of dengue and now we have fifty to hundred cases. This is the graph obtained from the MOH website which is publicly accessible. Last year in the September October period we had thousand odd cases and now this is earlier this month less than a hundred. So the answer to the question is very well. And this is on the rising trend if you look at the years 2003, 2004, 2005. The important people became alarmed when there was a bed shortage in public hospitals due to the number of dengue patients.
What was different between 2005 and previously?
There was a lot of extra government effort. Prime minister was involved, national experts. People did a really good job of going around searching for mosquitoes and destroying their breeding grounds and even had a few weekends of "seek and destroy". Big cooperation where volunteers and officials from the environmental agency went around looking for mosquitoes.
Why wasn't it done any earlier?
That's a hard question to answer. It just shows that when a lot of effort is put in we can stop the problem. We haven't changed the way we fumigate much. For many years people say that we don't really find many mosquitoes in the house. Mosquito house index. If that's the case then why does the effort put in make any difference? Maybe it was just previously understaffed. As the minister said on the weekend, we are prepared for another outbreak. As long as there is motivation by the government we will continue to control it well. During the peak of the outbreak there were a lot of theories. Have the mosquitoes become smarter or are they hiding somewhere where we can't reach? People were talking about the trees which the fumigation can't reach. Local research shows that the mosquitoes can now fly up to twenty stories and fly for a long period of time, more than a kilometer. But in Singapore that doesn't really matter as people live so near to each other. The real problem here is that people weren't finding the mosquitoes. Either there weren't enough officers or they are not experienced enough. When they finally looked into it they found it and destroyed it. Dengue was never really a medical problem. More of an environmental problem. Dengue was wiped out of America in the 1970s but when people neglected it, it recurred and repopulated the whole of South America. Whether or not those numbers of low mosquito house index were real or people just weren't finding it, clearly, if you send someone who's inexperienced or don't send enough people they won't find it. In Jurong they were basically employing all the neighborhood volunteers and with enough people they were able to solve the problem. The fact that when people put in that extra effort and were able to destroy the mosquitoes suggests to you that the mosquitoes actually were there.
How close are researchers to finding a cure for dengue?
There's actually no real treatment for dengue. People are working on a vaccine. Dengue has four serotypes and whatever vaccine you produce has to cover all four. We will know more in the next few years but at this stage there's no real vaccine or treatment for dengue. The management for dengue is just prevention. Try to get rid of mosquitoes. And when you do get dengue infections it's just give symptomatic treatment. Panadol for fever, make sure you drink a lot of water, give them medication to relieve nausea and tablets to relieve itch and rash. And for the small minority that become really sick we give them fluids by infusion/needles and most of them get well. Unlike bacterial infections where you can take antibiotics, we don't really have medication that cures dengue. Majority of dengue patients just feel unwell. They are not really sick.
Are there additional research/measures done in tan tock seng to treat dengue?
There are two studies. We are analyzing the 2004 dengue patients to try and find out if there are any symptoms or signs or basic blood tests that can help us predict how to best manage them and when to admit them to hospital, and who can be predicted to be very sick from dengue. As I said earlier, only a small minority will become sick from dengue. What we call dengue shock syndrome. We don't have the final results yet. The other study is called the Eden study and is headed by Doctor Adrian Hong. he was trying to look at is there any features in the patients whether is it symptoms that the patient complains of or signs that we find when we examine the patient or blood tests in the early few days that can predict which patient is going to be sick and going to have to require hospitalization. This is being done at the polyclinic level. Most dengue patients don't come into hospital until day four or five if we can find out something in the first few days and can know that these people are going to do worse, this would be a useful thing for us, to focus on this minority. That study was started mid last year and is still ongoing.
What are the chances of a person recovering from dengue?
The majority will just recover naturally, over 90%. They get fever for five to seven days, feel pains here and there, stop going to school/work for a few days. But after that they get better. But about five to ten of them may contract dengue hemorrhagic fever. Blood vessels of the patient become leaky so the fluid in the blood vessels will leak out into parts of the body like the lungs and legs. Patients usually complain of swollen legs/hands and they may become breathless. These patients are the ones who are hospitalized.
Are there any factors to predict who will get dengue hemorrhagic fever?
Serotype 2 more likely to cause it. If you had dengue fever in the past, you are also more likely to contract it. Your increased risk is about 6 times. But your absolute risk is still very low because most people with dengue don't get hemorrhagic fever. Asian type of dengue virus also more likely to cause it, compared to the South American. Very young children in Thailand tend to develop severe hemorrhagic fever. Of the small percentage of people who develop hemorrhagic fever, even fewer of them develop dengue shock syndrome, which is where their blood pressure is low and they have an increased risk of death. The idea is to not let them worsen from hemorrhagic fever to dengue shock syndrome. People who died from dengue last year is less than 1%.
How can the family members help?
Encourage rest and make sure they drink a lot of fluids. Most people with dengue have no appetite. So long as they aren't vomiting they can drink water or soup. It is when they don't drink even water and have high fever that they can become dehydrated. If someone is vomiting a lot or having bad diarrhea then they might become dry easier. Old people also don't cope with this very well. As you get older your reserve is a lot less. We can also do a blood count everyday and monitor blood concentration and when it goes up people are more likely to develop hemorrhagic fever. For a small minority of patients, their blood count drops to a low ten to twenty thousand. These people are better observed in hospital.
How long and in what ways must a person be trained?
Not very long. Any doctor can treat dengue. Medical school is five years. Specialist doctors can teach young doctors. We actually use a dengue care path, which is a few pieces of paper which tells you what to do everyday and what to examine or ask.
How adequately prepared is Singapore for another dengue outbreak?
We should be okay. The government is very committed. If there is an increase in dengue cases again, the manpower will be provided to find the breeding areas for the mosquitoes and destroy them.
What is the possible damage and repercussions to Singapore's economy and society in such a case?
The main thing is that people will be taking time off work. A lot of people will end up in hospital and there would be a shortage of beds. If people remain vigilant and keep changing flower pot water etc. the bed shortage can be solved. We would know for sure whether we will have a problem after June.