Dengue fever is a flavivirus in the same family as Zika, West Nile Virus, and yellow fever viruses. It is spread by the bite of Aedes mosquitoes such as the Aedes agypti and Aedes albopictus. Dengue is caused by one of four viruses known as 1,2,3, and 4. It can cause mild flu-like symptoms, but if it progresses without proper medical care, it can be lethal. Dengue Hemorrhagic Fever (DMF) is a specific syndrome that tends to affect children under the age of 10 and is a leading cause of sickness and death in children in certain Asian and Latin American countries. Dengue is also common in the US territories of Puerto Rico, the US Virgin Islands, and American Samoa. In the United States, outbreaks have most recently occurred in Hawaii (2015), Florida (2013), and Texas (2013). Because the Aedes aegypti and Aedes albopictus are common throughout many parts of the United States, local spread of dengue is possible.
Mosquitoes become infected when they feed on a person who is already infected with dengue, and then they spread it by feeding on other people. Dengue can also be transmitted from mother to child during pregnancy or at birth.
Signs and Symptoms
Dengue causes a flu-like illness. It typically begins with a high fever (104’F) that develops 3 to 7 days after exposure. Individuals may also experience a combination of the following symptoms: headaches, joint pain, pain behind the eyes, muscle pain, fatigue, nausea, vomiting, and skin rash. Severe dengue can result in severe stomach pain, bleeding from the nose or gums, and vomiting blood. People are more likely to have an acute response if they have previously been infected with a different form of Dengue.
Treatment and Vaccine
The virus has four strains, which is complicated for medical professionals to manage. Successfully fighting off one strain of dengue does not create immunity from other strains. People who have successfully beaten one strain are more at risk from complications if they get a second one. There is no treatment for dengue virus infection or disease. Treatment of symptoms is simply resting to support the immune system and acetaminophen to relieve fever and pain. However, the pharmaceutical company Sanofi created a Dengue vaccine, which was approved for use in the USA in May 2019.
Mosquitoes that transmit Dengue
The two mosquitoes of primary concern are the Aedes aegypti and the Aedes albopictus.
Aedes aegypti, the yellow fever mosquito, has a black body with a white violin shape design on its thorax. These mosquitoes do not fly far from their breeding grounds and usually take their blood meals in the early morning or late afternoon. The Aedes aegypti mosquito is also known to transmit other flaviviruses such as Zika.
Aedes albopictus, better known as the Asian tiger mosquito, is black with white stripes on its head and thorax. It has been adapting to our cooler regions by diapausing (a period of suspending its development) in the winter. The Asian tiger mosquito is also known to transmit other flaviviruses such as Zika, West Nile Virus, and yellow fever.
Aedes aegypti and Aedes albopictus are both floodwater mosquitoes, meaning that they lay their eggs in containers that will flood with water. When the rainwater fills a container to the point it reaches the eggs, depending on the time of year and temperature, the eggs will hatch. These mosquito species practice skip oviposition, in which they lay eggs in many different places. The eggs hatch into larvae and live in the water before they transform into a pupa and then emerge as an adult mosquito. They cannot survive without this water, and this is why “tip and toss” any standing water on your property during mosquito season is essential.