Dengue fever scare for Hong Kong family highlights rising risk from disease
A family's holiday scare underscores the rise in cases of dengue fever across Southeast Asia
On a recent family holiday to Bali, Lindsey Price's 10-year-old daughter Lauren came down with a sudden high fever of 39 degrees Celsius on the second day of their trip.
The family controlled the temperature with fever medication, but on the third day, Lauren began vomiting and collapsed.
A local doctor recommended she have a blood test, which confirmed that Lauren had dengue fever. It's a common virus borne by female Aedes aegypti mosquitoes.
Also known as break-bone fever because of its sudden high fever, severe headaches, joint and muscle pain, it normally manifests four to six days after infection. Other symptoms include nausea, vomiting, skin rashes and even mild bleeding.
According to Dr Faisal Nahdi, consultant paediatrician for the Rainbow Group of Hospitals in Hyderabad, India, children, unlike adults, may often experience symptoms similar to those of the common cold and gastroenteritis.
They have a greater risk of severe complications, although initial symptoms are generally mild and are mostly associated with high fever.
Younger children and people who have never had the infection before tend to have milder cases than older children and adults. But serious problems can develop.
These include dengue haemorrhagic fever, a complication characterised by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, enlargement of the liver, and failure of the circulatory system.
Nahdi says: "Over the last 12 years of treating patients with dengue, I've come across many cases which affect other [bodily] systems. That is either in isolation, or along with classic dengue symptoms like liver failure and neurological involvement, which can even cause death."
Since there is no vaccine or treatment for dengue, other than managing and controlling it with paracetamol, hydration and rest are the best options.
So Price kept Lauren in the comfort of their villa in Bali, while a doctor came by each day to monitor her and perform blood tests to check her platelet level. They quickly learned that it was a waiting game, as days one to three are when the high fever sets in and fluids are critical to keeping the body hydrated.
Days four to six are the critical stage where the blood platelet level can drop dangerously and sufferers can experience complications of dengue haemorrhagic fever or dengue shock syndrome.
Price says: "Luckily for our daughter, she didn't experience any complications, and the fourth blood test revealed she was in the recovery phase with her blood platelets rising back to normal levels."
Between 2004 and 2013, a total of 505 cases of dengue were recorded in Hong Kong, none of them fatal. According to Centre for Health Protection data, the incidence of dengue has been on the rise in the city over the last 10 years, with 31 cases in 2004, 58 cases in 2007, 83 cases in 2010, 103 cases in 2013 and 104 cases up to November 27 this year.
This is probably related to the increased incidence of dengue in Southeast Asia and recently in parts of southern China.
It is under control in the city due to preventive measures, says Dr John Simon, a specialist in tropical medicine who has seen about 200 imported dengue cases during the course of his practice over the past 20 years.
"I used to think it was because we didn't have Aedes aegypti in Hong Kong - only Aedes albopictus. The latter mosquito is said to be a less efficient vector than the first. The first is common in Singapore, Bangkok, Manila, and Jakarta," Simon says.
"But the recent huge outbreak [this summer] in Guangdong, where I believe they only have Aedes albopictus [mosquitoes], has made me think again. The reason it is well controlled in Hong Kong is because the government has an excellent mosquito control unit, with very good surveillance and eradication of larvae.
"Also, all cases are reported to the government, and are isolated. The colder climate in winter in Hong Kong [than in Southeast Asia] may also play a part. But dengue transmission can occur until the temperature drops to nine degrees [Celsius]," says Simon.
In Hong Kong, dengue is statutorily notifiable; all medical professionals are required to report suspected and confirmed cases. Price reported Lauren's case, as the normal incubation period is three to 10 days and Lauren presented with symptoms just two days after arriving in Bali.
Prior to leaving Hong Kong, she had attended a school camp at the government-run Shui Long Wo campsite in Sai Kung and returned with mosquito bites. The Centre for Health Protection has classified Lauren's case as possibly local.
As a dengue vaccine is still undergoing clinical trials, Dr Ivan Hung, a specialist in infectious diseases and clinical associate professor in the department of medicine at University of Hong Kong, advises travellers to wear loose, long-sleeved and light-coloured clothing, apply insect repellent which contains the chemical DEET, use a mosquito screen or nets in rooms that are not air-conditioned, and try to stay indoors at dawn and dusk, when the mosquitoes which carry the dengue virus are most active.
Although they have lived in Asia for more than 25 years, and travelled extensively, Price and her family had never been aware of the risk of contracting dengue.
Since returning to Hong Kong, she's been trying to raise awareness of dengue, and publicise the importance of recognising the symptoms to avoid complications.
"We will never forget the doctor saying that our daughter could die," Price says.
A traveller's guide to dengue prevention
Wear loose, light-coloured clothes that cover your hands and your legs.
Use repellent spray that contains diethyl-meta-toluamide (DEET) on exposed parts of the body and clothes. The concentration of DEET should not exceed 35 per cent for adults and 20 per cent for children. Pregnant women and infants should not use such repellents.
Eliminate stagnant water in open drains and even in plant pots, as it could be a breeding ground for
Aedes aegypti mosquitoes.
Use mosquito screens or nets in rooms that are not air-conditioned.
Take your own aerosol insecticides and bed nets as your next line of defence.
Permethrin cream or lotion, listed on the World Health Organisation's list of essential medicines, should be part of your travel first-aid kit.
If you feel unwell after visiting a dengue-prevalent area, seek medical advice quickly and provide travel details to your doctor.