What type of pathogen is dengue fever




















What is Dengue? Areas with Risk of Dengue Dengue outbreaks are occurring in many countries of the world. New Dengue Vaccine A new dengue vaccine is approved for use in children aged 9 to 16 years with laboratory-confirmed previous dengue virus infection and living in areas where dengue is endemic common.

New dengue vaccine. About Dengue. Statistics and Maps. For Healthcare Providers. New infections in humans can occur when saliva that contains virus is injected into a non-immune host during subsequent blood meals. However, there is no evidence that these viruses are responsible for large epidemics.

The virus circulates between humans in village and urban areas. Dengue is essentially a village and urban disease because its principal vector, Aedes aegypti, is abundant in the peridomestic environment. The species is a highly effective vector: it feeds almost exclusively on humans, breeds in small man-made articles that contain water, rests inside buildings and is rarely found more than 50 meters from human habitation.

Its biting habits tend to be diurnal. A second species, the Asian tiger mosquito, Aedes albopictus , can be common in the peridomestic environment, particularly in urban areas with abundant vegetation.

Nevertheless, epidemics have occurred in places where this mosquito was the only vector species present. Aedes aegypti was once present in Europe and responsible for large epidemics of yellow fever and dengue. Its disappearance after World War II has never been explained. Currently it is present in Madeira and it is conceivable that it could become re-established and widespread in Europe. The Aedes albopictus mosquito present in southern Europe is well adapted to winter temperatures, and is likely to extend its range northwards.

It is already a major nuisance in several Mediterranean countries, and was responsible for autochthonous cases of dengue in France and Croatia in Another approach is the detection of the non-structural-1 NS1 dengue antigen up to day four post-onset. However sensitivity of the assay is depending on the serotype. Determination of the dengue serotype and genotype is important for epidemiological studies; co-circulation of different dengue serotypes during an outbreak is not uncommon.

Viral isolation is done for research purposes. Serological diagnosis can be performed by detection of dengue IgM antibodies in serum specimen from day 5—6 of illness, or detection of a four-fold rise of specific IgG antibody titre on a pair of sera acute and convalescent specimens. In a secondary dengue infection, dengue IgM antibodies usually appear earlier from day 2—3 post onset and with a shorter duration.

An increase of dengue IgG titre has to be measured. Serological cross-reactions between dengue viruses and closely related flaviviruses are reported. Case management and treatment Supportive therapy is the only option, with strict avoidance of aspirin and other anticoagulants Epidemiology Dengue is endemic in more than countries in Africa, the Americas, South-East Asia, the Western Pacific and the eastern Mediterranean.

ECDC monitors the current dengue transmission worldwide. Dengue viruses are highly mobile, transported by infected travellers; all four serotypes now co-circulate in many cities around the world.

The number of dengue cases has been increasing dramatically in the past few decades and large outbreaks have been reported. Imported cases of dengue are frequently reported by travellers returning to the EU from endemic areas and may generate a local transmission in areas where the vector is present.

A small number of people who experience these symptoms will go on to have severe dengue which can include:. Cases of dengue virus occur in northern Queensland from time to time when travellers who have been infected overseas return and introduce the virus to the local mosquito population. Dengue virus is not transmitted spread from person to person.

Only infected mosquitoes transmit dengue virus. It is thought that the mosquito contracts the virus when it bites an infected person. The mosquito is then infective for the rest of its life and can spread the virus every time it bites someone. At least three different kinds of mosquito in Australia are suspected to be dengue carriers. They are Aedes aegypti, Aedes scutellaris and Aedes katherinensis.

These mosquitoes are found in northern Queensland, the Northern Territory and northern Western Australia. They are not found in Victoria. Protect yourself against mosquito bites to avoid dengue virus and other mosquito-borne diseases in dengue-affected areas. Suggestions include:. See a doctor immediately if you think you may have dengue virus. Early diagnosis is important to reduce the risk of complications and avoid further spread of the virus.

Your doctor will ask about your medical history, including any travel, and will do a physical examination. Blood tests are required to diagnose dengue. There is no specific treatment for dengue virus. Medical care aims to manage the symptoms and reduce the risk of complications while the person recovers. Most cases of uncomplicated dengue virus resolve fully within one to two weeks.

During this time, your doctor may advise:. This means you can be infected again in the future by one of the other three virus types. Your risk of developing severe dengue fever increases if you get dengue fever a second, third or fourth time. Severe dengue fever can cause internal bleeding and organ damage. Blood pressure can drop to dangerous levels, causing shock. In some cases, severe dengue fever can lead to death. Women who get dengue fever during pregnancy may be able to spread the virus to the baby during childbirth.

Additionally, babies of women who get dengue fever during pregnancy have a higher risk of pre-term birth, low birth weight or fetal distress. In areas of the world where dengue fever is common, one dengue fever vaccine Dengvaxia is approved for people ages 9 to 45 who have already had dengue fever at least once. The vaccine is given in three doses over the course of 12 months. The vaccine is approved only for people who have a documented history of dengue fever or who have had a blood test that shows previous infection with one of the dengue viruses — called seropositivity.

In people who have not had dengue fever in the past seronegative , receiving the vaccine appears to increase the risk of severe dengue fever and hospitalization due to dengue fever in the future. Dengvaxia is not available for travelers or for people who live in the continental United States. But in , the U. Food and Drug Administration approved the vaccine for people ages 9 to 16 who have had dengue fever in the past and who live in the U.

Virgin Islands — where dengue fever is common. The World Health Organization stresses that the vaccine is not an effective tool on its own to reduce dengue fever in areas where the illness is common. Preventing mosquito bites and controlling the mosquito population are still the main methods for preventing the spread of dengue fever.



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