Dengue is the fastest-growing mosquito-borne viral infection, and its impact today is 30 times greater than that of 50 years ago. In the 1970s, less than 10 countries reported dengue epidemics. Now over 150 countries suffer dengue threat. While Latin America, Southeast Asia, and the Western Pacific report most of dengue cases, many African countries including Europe, the USA and China also experience dengue epidemics. The World Health Organization (WHO) estimates that about 40 percent of the world’s population irrespective of their ages is at risk of being infected with dengue.
The dengue mosquito
Scientific name: Aedes aegypti
Distinct physical features – black and white stripes or spots
Bites during the day
Lifespan: 2-4 weeks
Does not fly far (up to 400 meters) - lives near the breeding areas; this means that people rather than the mosquito are likely to move the disease from place to place
Lays eggs. the larvae develop even in very shallow water
Eggs can survive desiccation (drying out) for long periods and hatch once re-submerged in water, making control of this species very difficult
Only the female Aedes mosquito feeds on blood. This is because they need the protein found in blood to produce eggs. Male mosquitoes feed only on plant nectar
Female Aedes mosquito lays about 300 eggs at a time in different spots, about 2-3 times during its lifespan
Four types of dengue virus strains have been identified and the infection causes a wide range of symptoms. Having been infected once does not protect you from the other three strains of the virus. The second time symptoms are more severe.
Infection spread through mosquito bites; all it takes is a single bite from an infected mosquito.
Spread of dengue
Dengue spreads in many ways. Warm temperatures spread dengue transmission by increasing survival and biting rates, as well as decreasing the extrinsic incubation period of the dengue virus in mosquitoes. Dengue, being a tropical fever, thrives in warm and wet conditions. Climate Change, El Nino effect, increased rainfall and man-made environment increase the spread.
Breeding grounds
Stagnant drains; gutters; sloppy garbage collection and disposal; construction sites with areas of stagnant water; discarded tires, plastic containers, and flower pots; schools, hospitals, government buildings with vulnerable breeding areas and unkept grounds and storerooms; polluted canals and waterways that snake through many tenements in the city and suburbs; abandoned houses and premises and dilapidated buildings, among others.
Present situation
The National Dengue Control Unit have taken many efforts for the last decade to control dengue. Fogging, inspecting households, and enforcing fines are some of them. The information released by this unit indicates that the highest number of cases for 2016 were recorded from Colombo (15,400), Gampaha (6,298), Galle (2,808), and Kalmune and Ampara (815), with 815 deaths in 2016.
Many governments in other developing and developed nations are already pursuing aggressive means to fight dengue. Current efforts focus on prevention, such as using insecticides or reducing potential egg-laying habitats for dengue mosquitoes. Various organisations are also making progress in terms of immunization, with the most advanced vaccine candidate soon to be introduced in endemic countries.
However, this is not enough – elimination of dengue calls for a globally coordinated and integrated approach, which risks becoming a global pandemic.
Dengue Control – Think outside the Box
For years, all kinds of warnings were issued, precautions announced and anti-dengue drives were carried out in earnest, but we are still back at square one. Our health care system has made great strides in effectively managing and treating the disease; however, the recent increase in a hemorrhagic strain of dengue threatens to overburden our health care infrastructure. Dengue has become an epidemic in Sri Lanka. It is time that the health authorities got back to the drawing board and map out a definitive plan to contain the epidemic.
Let’s learn from others – look at the successful campaign against dengue in Lahore, Pakistan where 20,000 cases in 2011 were brought down to a couple of dozens in 2013 (http://www.npr.org/sections/health-shots/2013/09/16/223051694/ how-smartphones-became-vital-tool-against-dengue-in-pakistan)
The key steps taken by the Lahore campaign that can be incorporated by the Dengue Monitoring Unit in Sri Lanka:
* A Dengue hotspot map of the Colombo District, the most heavily affected area to start off with * A Google map that correlates the locations of dengue cases and hot spots for mosquito larvae.
* Easy to remember telephone numbers to report any dengue breeding locations
* Photos of potential dengue breeding areas/locations and address of breeding sites, and requesting the general public to send information on any potential breeding sites to the Monitoring Unit
* Dedicated Staff that can follow up on the photos sent and any complaints. They should also record the actions taken and follow up activities
This information will help the dengue control unit to target the areas that are breeding grounds for dengue, and also future potential breeding grounds.
The success story of the Lahore programme was that the authorities were able to destroy potential breeding areas of larvae (with the data gathered the previous year), before the onset of dengue following the rains.
* Create a similar App or new one – this can be done by Sri Lankan IT researchers and students, together with the Dengue Control Unit, taking the local context into account. We already have an App called “Mo Buzz dengue”, but no one seemed to be using it – may be it is not user-friendly, or the authorities do not get the correct information to act on it or only a few people are aware of it. We should find out the format of the Apps used in Lahore to make it effective.
These methods need a little technology and smart phones, but it is easy to implement and can be done rapidly. Lahore has demonstrated that it can be done by cooperating with the general public and dedicated officials.
The Health Ministry authorities should take a holistic view of the whole problem and attack it at the core, instead of relying on piecemeal solutions. All segments of society – households, schools, temples and other places of religious worship, government departments and construction sites should be co-opted to carry out a successful anti dengue drive. Imposing fines of Rs. 25,000 as suggested could be an effective deterrent
Awareness creation
The public can also cooperate by adding salt water or soapy water to small pools of water or stagnant drains to destroy dengue larvae.
Dengue is spread through mosquito bites from an infected person to another. Infected persons should sleep under a net till the fever subsides and they are no longer infectious. Homes of infected persons should be immediately fogged so that infected mosquitoes in the vicinity are immediately destroyed before further spread of the disease. Neighbours should be informed, so they can remain vigilant for a few days following detection of initial case in their vicinity.
We are talking here of saving lives, especially those of the most vulnerable in our population- young children and the elderly. Together we can do it; we can beat the dengue epidemic– let's do it.
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Dengue prevention
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