Fiji Islands - Away with the mosquitoes

[Snowy Owl]

Away with the mosquitoes

http://www.fijitimes.com/story.aspx?id=47798

Verenaisi Raicola
Wednesday, September 06, 2006

THE Clean Up Fiji Campaign that will be held next week is a step in the right direction to prevent diseases spread by mosquitoes.

Mosquito-borne diseases such as dengue fever, for example, would be prevented if breeding grounds were destroyed.

But in order to eliminate breeding grounds, people must be concerned about their environments.

Not only that but those facing intermittent water supplies also need to be careful when they store supplies.

Health authorities have confirmed three cases of dengue fever.

Head of the National Centre for Communicable Diseases, Doctor Joe Koroivueta said water shortages indirectly contributed to dengue.

How?

During the shortages, people store water during the dry season and mosquitoes breed in these storage containers.

Pot plants and tyres are also fertile mosquito breeding grounds.

But nothing is done until there is a dengue outbreak then everyone panics.
And sometimes it is too late when infected people start bleeding.

History tells us that dengue fever is nothing new here.

Fiji reported its first clinical case of dengue fever in 1885.

During the 1974/1975 epidemic, 2000 cases were reported and 12 people died.

There was another outbreak in 1980 where there were 170 reported cases but no fatalities.

In 1981, there was an outbreak of the type IV virus where hundreds of people were treated and one person died.

In 1982, the epidemic struck again resulting in 546 reported cases but no deaths.

In 1992, three people died during an outbreak and a year later, 237 cases were reported but there were no deaths.

A 1998 outbreak of dengue fever resulted in 25,000 cases and 14 deaths.
Ministry of Health national advisor on family health, Doctor Josaia Samuela said dengue fever was a viral infection.

"In recent years, it has become a major public health concern for Fiji and other Pacific island countries with a severe, flu-like illness that can affect anyone, seldom causing death."

Dr Samuela said dengue viruses were spread through the bites of infective female Aedes mosquitoes.

Mosquitoes generally acquire the virus while feeding on the blood of an infected person. After harbouring the virus in its body for about 8-10 days, the female mosquito is capable of infecting people during a bite. The female mosquito thus becomes the main vector in transmitting the virus to susceptible individuals for the rest of its life.

At present, the only method of controlling or preventing dengue is to destroy the mosquitoes that harbour and carry the virus.

In Fiji, the Aedes aegypti and Aedes albopictus mosquitoes breed primarily in man-made containers like pot plants, metal drums and containers used for storing water, as well as used car tyres and other items that collect rainwater.

Mosquito breeding can be controlled through two main methods: cleaning the environment or water-holding containers and tyres and using chemicals to spray and kill adult mosquitoes.

"Proper covering of water-holding containers to prevent access by egg laying female mosquitoes is very important," Dr Samuela said.
He said insecticides (chemical sprays) must be used regularly to destroy breeding places.

"During dengue outbreaks, emergency control measures may also include the use of large spraying machines mounted on trucks," Dr Samuela said.
"However, the killing effect is only transient, with variable effectiveness because the spray droplets may not reach the breeding places of these mosquitoes," he said.

To prevent dengue fever, we must ensure that our homes and physical environments are free of water-holding containers that can become breeding grounds for mosquitoes.

Dr Samuela said people could use protective materials like mosquito nets when there were lots of mosquitoes around the house. It is a simple protective measure that could save lives.

"But people must seek early medical attention if simple fevers and body aches do not subside within two or three days because it could be either dengue or one of the other serious diseases like leptospirosis or typhoid."
He said enforcing public health legislation to ensure that all vacant properties in our localities were cleared of bushes and rubbish that could harbour and allow the breeding of mosquitoes was also important.

Dengue is prevalent when travellers come into the country with the infection.

"Once mosquitoes are able to feed on that infected person, the chance of a dengue outbreak increases as mosquitoes spread the virus through bites," Dr Sameula said.

"Whether it is closely linked to the increase in mosquito population is possible but then the dengue virus has to be harbouring in those mosquitoes. This occurs following periods of heavy rain," he said.

Dr Samuela said dengue was an infection due to a virus carried around by mosquitoes.
The only way to avoid it was either to get rid of all mosquitoes or to develop a vaccine against the virus.

"Both of these methods have not been realised and like most viral diseases, there is no specific cure for dengue fever. Antibiotics do not help," Dr Samuela said.

He said the clinical features of dengue fever varied and could be confused with influenza and other bacterial infections like leptospirosis and typhoid fever.

"The classical incapacitating form of the illness presents itself with sudden high fever, severe headache, pain behind the eyes, muscle and joint pains, and even a rash.

"Dengue can only spread from an infected person to another person by the bite of female Aedes mosquitoes. It does not spread directly through personal contact, cough or through sexual means."

Dr Samuela said from experience, dengue had been fatal with younger children as seen in the 1989/1990 outbreaks.

"People who suffer from dengue fever have no risk of death but some of them develop dengue haemorrhagic fever or dengue shock syndrome. In some of these cases, death can occur," he said.

"With proper treatment, the patients with dengue haemorrhagic fever and dengue shock syndrome can recover fully. Good treatment provided in time can save most lives," he said.

"There are four distinct, but closely related, viruses that cause dengue.

"Recovery from infection by one provides lifelong protection against that particular virus but confers only partial and transient protection against subsequent infection by the other three dengue viruses," he said.

Major population and demographic changes have occurred by way of uncontrolled urbanisation and concurrent population growth.

These demographic changes have resulted in substandard housing and inadequate water, sewer, and waste management systems, all of which increase mosquito population densities and facilitate the transmission of dengue.

"Increased travel by airplane provides the ideal mechanism for transporting dengue viruses between population centres of the tropics, resulting in a constant exchange of dengue viruses," Dr Samuela said.

"We need to fear further outbreaks of dengue because only time can tell when another one can become an epidemic," he said.