It’s that time of the year again: dengue is on everybody’s mind. So far in this year, more than 17,000 cases have been reported in India though the true number is likely to be much higher because roughly three-quarters of the cases show no symptoms. Fortunately, the likelihood of death is low — under 1% of all cases with dengue symptoms result in death. But getting dengue a second or third time significantly increases the risk of the more severe form of the disease — dengue hemorrhagic fever — which can lead to death.
But India is not the only country facing the problem. More than 100 countries report dengue cases each year — a total of 50-100 million cases and about 20,000 deaths. Though dengue is certainly a serious public health problem, it pales in comparison with diseases like malaria (800,000 deaths each year, 50,000 in India alone) and tuberculosis (around 1.5 million deaths each year worldwide and over 300,000 of these in India).
There are several theories why dengue is getting worse worldwide. One of the reasons could be climate change because mosquitoes that cause dengue are sensitive to temperature and humidity. Another explanation is that as households get wealthier, there are more pockets of water in, say, discarded tyres or overhead tanks. In a sense, each of us is responsible.
Countries that have controlled dengue have managed to do so through strong public health systems and community action, which have gone a long way towards ensuring that there are no standing pools of water. Even a small cup, vase or dog’s bowl collecting rainwater can breed Aedes aegypti, the mosquito that causes dengue.
The sense that dengue is someone else’s problem, including that of the municipal department, makes the situation worse.
Let’s face it, with more important priorities like containing malaria, tuberculosis or diarrheal diseases, our overstretched municipal and public health authorities are unable to do much beyond the occasional anti-mosquito fogging, which has limited effect on the transmission of dengue. Larval control will be helpful where there are larger pools of standing water. Some wealthier countries impose fines on home owners who allow water to accumulate, but that may not be feasible in our system where even jumping a traffic light rarely attracts a penalty.
Dengue calls for individual responsibility and for local residential associations to come together to protect themselves. Fortunately, Aedes aegyptis doesn’t fly long distances during its lifetime — it typically travels less than a 100 metres. In other words, if your community eliminates mosquito breeding, it is your community that will enjoy the benefits of fewer dengue cases.
- Ramanan Laxminarayan is vice-president, Research and Policy, Public Health Foundation of India
The views expressed by the author are personal