Rains To Bring Dengue Outbreak
- In June 5,700 cases were reported which was more than double the 2,400 cases reported in May this year.
By Dinouk Colombage
As the rains return to Sri Lanka the country is preparing itself for another outbreak of dengue, according to the Chief Medical Officer (CMO) at the Colombo Municipal Council (CMC), Dr Pradeep Kariyawasam.
He said that Colombo, and the rest of the country, were experiencing a downward trend in the outbreak of dengue. “While June, July and August recorded a high level of reported cases, September has only seen 36 cases in the capital. This is a positive sign, however, with the recent rain we are preparing for a potential outbreak in October”, he said.
Kariyawasam added that they were confident that the city would be better prepared to handle an outbreak of dengue, having fought this strain continually this year. “In September the number of recorded cases so far has been on the decline. We are continuing to inspect properties in the city and surrounding areas while also carrying out spraying near any possible breeding grounds”, he explained.
The CMO further said that the early detection tests which were on offer for patients suspecting they were suffering from dengue had assisted in reducing the severity of the disease. “Dengue is rampant around the tropical world, especially during the monsoon seasons. Having a high number of cases is a concern but we are taking all possible steps to counter it”, he said.
However, the Epidemiology Unit at the Ministry of Health portrays a different picture of the fight against dengue. The three months leading up to September have shown a large scale increase in the number of reported cases of dengue. In June 5,700 cases were reported which was more than double the 2,400 cases reported in May this year. While the number of cases in August dropped to 4,600 there was still a marked increase.
With dengue cases on the rapid increase in Sri Lanka a proposed Center for Dengue Research is to be established at the Microbiology Department of the Medical Sciences Faculty at the Sri Jayewardenepura University.
Prof. S. Senanayake, a contributing lecturer at the Medical Sciences Faculty, said that they had been studying the current strain of virus that is transmitted by the dengue mosquito in an attempt to create a vaccine. “The problem with developing a vaccine for the virus is that it continues to change meaning the vaccine will also have to change with it. The other problem we face is that the virus only affects humans and so we cannot test the vaccines on animals, which means we have to work very slowly”, he explained.
Senanayake drew attention to a vaccine that was being developed in Thailand by the French drug maker Sanofi SA. “In that instance the tests were not as successful as they had hoped. According to the reports I have seen they claim that it was less than 40% effective. But I still find this positive as it shows that a vaccine can be developed against the virus”, he said.
In Thailand the vaccine was administered to 4,000 people who had been exposed to the dengue carrying mosquito. According to the drug makers’ findings the reason behind the low success rate was that there are four different strains of the dengue virus prevalent in the region, and only three of the strains were combatted by the virus.
While Sri Lanka struggles to contain the outbreak of the dengue virus, other countries around the world are suffering similar uphill tasks.
According to World Health Organisation (WHO) dengue is endemic in more than 100 countries in the Americas, the eastern Mediterranean, Southeast Asia, the western Pacific and Africa, making outbreaks, and even epidemics, a common occurrence. Yearly there is an estimated 50 million cases of dengue. The number of cases of dengue has increased over 30 fold since it was first identified 60 years ago, according to Dr Michael Crawford, researcher at the WHO.
Crawford said that mapping the distribution of dengue cases on yearly basis is difficult which makes combatting the virus that much harder. “The outbreaks are all over the world, and each year they are more prevalent in one area than another making it impossible to detect any patterns,” he said.
While it is difficult to estimate how far up Sri Lanka is ranked in the number of dengue cases the number of reported cases in Thailand, another country suffering an epidemic, will put it into context. This year alone there have been 17,086 patients in Thailand, while in Sri Lanka there have been 29,762 cases reported up till September.