Understanding Dengue: What to know and common terms associated with virus

Regional Vector Control Officer at the Western Regional Health Authority (WRHA), Ryan Morris. (Photo: Dwayne Young, JIS)

As the Government intensifies its campaign against the dengue virus, it is important that all Jamaicans have a full appreciation and understanding of the technical terms and jargons associated with the disease.

 These include dengue fever, Aedes aegypti and Aedes index.

Vector Control Officer at the Western Regional Health Authority (WRHA), Ryan Morris, said that a full understanding of the disease and methods used to curtail its spread are often impeded by technical terms.

As such, he argued that knowledge of dengue-related jargon will better enable Jamaicans to join in the national discourse and the fight against the mosquito-borne disease.

Morris explained that dengue fever is a mosquito-borne disease caused by the dengue virus. Symptoms typically begin three to 14 days after infection, and may include a high fever, headache, vomiting, muscle and joint pains, and rashes.

The Aedes aegypti mosquito is the primary vector of dengue.  The virus is passed on to humans through the bite of an infective female Aedes mosquito, which mainly acquires the virus while feeding on the blood of an infected person.

The mosquito can be identified by the white bands on its legs and a silver-white pattern of scales on its body.

It breeds in any collection of water, including discarded tins, cups, glasses, bottles, tyres, water drums, flowerpots, and coconut shells.

Prime Minister Andrew Holness and Health Minister Dr Christopher Tufton were among several notable government officials who participated in National Dengue Clean-up activities in the Corporate Area on Saturday, January 25. (Photo: JIS)

Turning to the Aedes index, Morris said that this is critical to vector control as “it gives us an idea as to what is happening, as well as what needs to be done”.

The index refers to the percentage of premises or homes in a limited, well-defined space, where actual breeding of Aedes aegypti is found and the total number of houses examined in that area.    

“That, within itself, would tell us whether we are high risk or low risk based on the percentage of the given space which is actually breeding the mosquitoes,” Morris told JIS News.

Other commonly used terms in vector control are larvicidal and adulticidal control, which speak to the eradication of mosquitoes at different stages.

“You have two aspects of control. You want to control mosquitoes from the larval stage, which is before they become adults. So, this is basically the stage in which you destroy the egg, you destroy the larvae with larvicides, which are placed in domesticated containers to kill the larvae. These larvicides are similar to what you would call insecticides,” Morris noted.

He explained that “adulticidal activity is what we commonly refer to as fogging or spraying. It is effective against only adult mosquitoes. It is done within a specific time frame, which is usually the fly time of the mosquito.”

Symptoms of dengue include sudden onset of high fever with severe headache, fatigue, pain behind the eyes, muscle, bone or joint pain, skin rash and vomiting or feeling nauseous.

Its more severe form, called dengue haemorrhagic fever, can cause haemorrhaging (internal or external bleeding), a sudden drop in blood pressure, and death.

Patients are advised to visit a doctor or medical facility; rest in bed; drink a lot of fluids (more than five glasses a day); use Paracetamol painkillers only; and avoid painkillers, containing aspirin, ibuprofen and other anti-inflammatory drugs, as they may increase risk of bleeding.

To prevent the disease, persons are advised to eliminate mosquito breeding sites by getting rid of items that collect water; installing mosquito nets over beds; wearing long-sleeve shirts and pants outdoors; using DEET (mosquito repellant), and regularly changing water in animal and pet containers.

A mosquito thwarted in it efforts to feed by a trusted net. (Photo: Readers’ Digest)

Dengue has been a national public health concern in Jamaica for some 50 years.

The disease is endemic in Jamaica and, as such, is usually seasonal. An increase in cases normally occurs after the rainy season from September to March.