What is dengue fever?
Dengue is a viral mosquito-borne disease caused by dengue virus (DENV), which primarily transmits to humans through the bites of infected female mosquitoes of the Aedes genus. Once an infected mosquito bites a person, dengue virus enters the bloodstream through the saliva of the mosquito and invades white blood cells. It multiplies within white blood cells which may trigger immune responses that cause symptoms. The resulting spectrum of disease may range from sub-clinical symptoms to severe, and occasionally life-threatening symptoms and complications. Read along to learn more about dengue fever, its epidemiology, symptoms, diagnosis, and treatment.
What causes dengue fever?
Dengue fever is caused by an RNA virus of the Flaviviridae family. There are currently five serotypes of dengue fever virus, which are DENV-1, DENV-2, DENV-3, DENV-4, and DENV-5. Whereas recovery from a certain serotype of dengue fever virus is known to provide lifelong immunity against infections with that serotype, it was found that cross-immunity against other serotypes was only short-term and partial. Moreover, recent research has demonstrated that subsequent infection with a different serotype may increase the risk of severe complications. The primary vector of dengue fever virus (DENV) is female mosquitos of the Aedes genus, particularly of the species Aedes aegypti and less commonly the Ae. albopictus. These mosquitoes are also vectors of chikungunya, yellow fever and Zika viruses.
Is dengue fever contagious?
Dengue fever does not spread through direct contact. The primary route of transmission of the dengue fever virus (DENV) involves Aedes mosquitoes. Maternal transmission between the mother and her baby prior to or during delivery has also been reported. Last, while the risk of infection outside of endemic areas are low, dengue can also transmit through infected blood transfusions and organ transplants.
How common is dengue fever?
Dengue fever is a common and widespread disease with up to 400 million dengue infections and 40,000 deaths occurring each year. According to World Health Organization, whereas it caused significant epidemics only in 9 countries before 1970, dengue fever is currently endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-East Asia and the Western Pacific. The Caribbeans, Central and South America, Southeast Asia, and the Pacific Islands are still considered areas of high risk for dengue, with Asia home to approximately 70% of all cases.
What are the signs and symptoms of dengue fever?
The symptoms of dengue fever typically emerge after an incubation period of 4 to 10 days following the initial exposure to the virus and typically fade away after 2 to 7 days. Most people infected with the dengue fever virus (DENV) are asymptomatic or develop mild symptoms. In fact, the data demonstrates that only 1 in 4 people with dengue infection experience symptoms. World Health Organization (WHO) examines dengue fever within two major categories depending on disease severity. Common symptoms of a dengue infection include fever together with symptoms such as nausea, vomiting, rash, swollen glands, fatigue, bleeding nose/gums, headache, as well as pain in joints, bones, muscles and behind the eyes.
The signs and symptoms of dengue fever can easily be confused with many other illnesses such as chikungunya, Zika, malaria and typhoid fever, and they can become severe within a few hours. Severe dengue, also known as dengue hemorrhagic fever, is a health emergency which affects 1 in 20 people infected with dengue fever virus (DENV). It is a life-threatening complication which may involve plasma leakage, severe bleeding, respiratory distress, fluid accumulation, and organ dysfunction. Severe dengue primarily affects infants, pregnant women, and people with histories of previous dengue infection. Signs indicating the manifestation of severe dengue include severe abdominal pain, liver enlargement, persistent vomiting, blood in urine, stool, or vomit, bleeding under the skin, bleeding gums or nose, fatigue, irritability, difficult or rapid breathing, and restlessness. If left untreated, severe dengue can cause dangerous complications such as shock, internal bleeding, organ failure or even lead to death.
How is dengue fever diagnosed?
There are various methods available for the diagnosis of infections with dengue fever virus (DENV). First, dengue fever virus (DENV) can be diagnosed via reverse transcriptase–polymerase chain reaction (RT–PCR) methods. Secondly, there are various serological tests, such as enzyme-linked immunosorbent assays (ELISA), that check for recent or past infections with dengue fever virus (DENV) via detecting anti-dengue IgG and IgM antibodies.
Rapid antigen tests (RAT) and rapid antibody tests are point-of-care (POC) diagnostic techniques that are commonly used to detect the presence of a virus’s viral antigen. These lateral flow immunoassay methods can detect a viral infection a few days after exposure to the virus or before symptoms arise. Rapid antigen test kits, as contrast to enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) assays, require less time, money, and laboratory equipment. Rapid diagnostic tests detecting NS1, a protein specific to the virus, have also been developed for the diagnosis of dengue fever. Moreover, rapid diagnostic tests not only eliminated the requirement for specialized equipment and trained staff, but also allowed quick result within 15 to 20 minutes. On the other hand, there rapid antibody testing methods available for the detection of dengue specific IgG and IgM antibodies.
To meet a revolutionary safe and rapid dengue virus diagnosis, check out our RapidFor™ Dengue IgG/IgM/NS1 Combo Rapid Test Kit, RapidFor™ Dengue NS1 Ag Rapid Test Kit, and RapidFor™ Dengue IgG/IgM Rapid Test Kit.
How is dengue fever treated?
There is currently no specific treatment for dengue fever. Mild cases of dengue fever typically recover shortly at home by resting and staying hydrated. The over the counter (OTC) pain and fever reliever drugs may also be helpful in managing the symptoms during recovery. However, experts warn that while acetaminophen and paracetamol are safe options, non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen should be avoided as they might increase the risk of complications. The treatment of severe dengue fever may require in-hospital treatment, intravenous (IV) fluid and electrolyte replacement, and blood transfusions.
The first vaccine against dengue fever, Dengvaxia® by Sanofi Pasteur, was licensed in 2015 and has recently been approved by regulatory authorities in approximately 20 countries. The clinical trials have demonstrated the efficacy of the vaccine against dengue fever in people with histories of past infection. Accordingly, the vaccine is currently targeted for use in endemic areas, for people of 9 to 45 years of age who have had minimum one previous dengue virus infection. There are also various vaccine candidates that are currently under evaluation including the DENVax vaccine developed by Takeda, the efficacy data of which demonstrated a promising 62% efficacy three years after vaccination and 83.6% efficacy at preventing hospitalization.
What are some of the efforts for raising awareness for dengue fever?
Public health authorities support the development and application of guidelines, strategies, and policies regarding the prevention and management of dengue fever outbreaks. They provide training and technical guidance for the prevention, diagnosis, management, and treatment of dengue fever. Moreover, these institutions hold campaigns to inform and educate the general public as well as medical professionals on dengue fever and on the novel methods and technology for its prevention, diagnosis, and treatment. Each year on 15 June, The Association of Southeast Asian Nations, or ASEAN, commemorates ASEAN Dengue Day to raise awareness against the disease and mobilize resources for its prevention and management.