Worst Dengue Outbreak in Decades: Only in Malaysia?

Number of dengue cases in Malaysia is hitting an all-time high. A total of 119,198 dengue cases have been recorded up to Nov 29, or an average of 359 new cases a day. And this is about 70 percent increase compared to the same period in 2018!

Malaysia is far from alone. Thailand, Vietnam, Bangladesh and Sri Lanka were also recording a record-high number of dengue cases, according to Azrul Mohd Khalib, chief executive of the Galen Centre for Health and Social Policy. Not only in Asia, dengue is spreading rapidly across Africa and the Americas. The Americas alone have reported more than 2.7 million cases by mid-November, the largest number since records began.

Dengue spreading across Asia and Central America

Who is to blame?

Dr Raman Velayudhan, coordinator of World Health Organization (WHO)’s vector management programme in Geneva says the Aedes mosquitoes are extending their reach as the global climate warms. Aedes mosquitoes in recent years have begun crossing into more temperate zones. Countries such as Nepal are beginning to report cases of dengue, chikungunya and Zika. Since 2010, dengue cases have been recorded in France, Italy, Portugal and Spain.

According to a new research (Ryan SJ, Carlson CJ, Mordecai EA & Johnson LR, 2019), with global warming, nearly a billion people could face their first exposure to viral transmission from either mosquito in the worst-case scenario within the next century. The largest increases in population at risk is consistently projected in Europe, with additional increases in high altitude regions in the tropics (eastern Africa and the northern Andes) and in the United States and Canada.

The economic burden

A 2015 research (Packierisamy P.R., 2015) estimated the cost of dengue in Malaysia at US$175.7 million a year, comprising the cost of illness (medical costs and productivity loss from illness and death) and the cost of prevention activities.

For prevention activities, Malaysia spent an estimated US$73.5 million on the national dengue vector control program in 2010. This spending represented costs per reported dengue case and per capita population were US$1,591 and US$2.68, respectively. About 92.2% of these costs were incurred at the district level, where most of the costs went to fogging activities and premise inspection for mosquito breeding sites.

The health ministry will be releasing Aedes mosquitoes that contain the Wolbachia bacteria in stages across the country to control the spread of dengue. This follows a pilot project in 2017 carried out in eight areas in Selangor that showed dengue cases reducing by 50% to 80%. The public also should raise their awareness on the severity of the rising dengue cases. Combating dengue is not only the Government’s job. What can we do? Open your windows when the council comes to fog your neighbourhood even though the chemical used is not very helpful to asthma sufferers!

Reference:

1. Think tank blames climate change for rise in dengue cases, 2 Dec 2019, FreeMalaysiaToday

2. WHO scales up response to worldwide surge in dengue, 14 Nov 2019, World Health Organization

3. Ryan SJ, Carlson CJ, Mordecai EA & Johnson LR (2019). Global expansion and redistribution of Aedes-borne virus transmission risk with climate change. PLoS Negl Trop Dis 13(3): e0007213.

4. Packierisamy PR, Ng CW, Dahlui M, Inbaraj J, Balan VK & Halasa YA, (2015). Cost of dengue vector control activities in Malaysia. Am J Trop Med Hyg. 2015.