Skip to main content

Dengue Fever


Dengue fever: also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.

Dengue is transmitted by several species of mosquito within the genus Aedes, principally A. aegypti. The virus has four different types; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. As there is no vaccine, prevention is sought by reducing the habitat and the number of mosquitoes and limiting exposure to bites.

Treatment of acute dengue is supportive, using either oral or intravenous rehydration for mild or moderate disease, and intravenous fluids and blood transfusion for more severe cases. The incidence of dengue fever has increased dramatically since the 1960s, with around 50–100 million people infected yearly. Early descriptions of the condition date from 1779, and its viral cause and the transmission were elucidated in the early 20th century. Dengue has become a worldwide problem since the Second World War and is endemic in more than 110 countries. Apart from eliminating the mosquitoes, work is ongoing on a vaccine, as well as medication targeted directly at the virus.

Comments

Post a Comment

Popular posts from this blog

Laboratory tests

Dengue fever may be diagnosed by microbiological laboratory testing.[23] This can be done by virus isolation in cell cultures, nucleic acid detection by PCR, viral antigen detection or specific antibodies (serology).[13][25] Virus isolation and nucleic acid detection are more accurate than antigen detection, but these tests are not widely available due to their greater cost.[25] All tests may be negative in the early stages of the disease.[5][13] These laboratory tests are only of diagnostic value during the acute phase of the illness with the exception of serology. Tests for dengue virus-specific antibodies, types IgG and IgM, can be useful in confirming a diagnosis in the later stages of the infection. Both IgG and IgM are produced after 5–7 days. The highest levels (titres) of IgM are detected following a primary infection, but IgM is also produced in secondary and tertiary infections. The IgM becomes undetectable 30–90 days after a primary infection, but earlier following re-inf...
Post a Comment
Read more

Diagnosis

The diagnosis of dengue is typically made clinically, on the basis of reported symptoms and physical examination; this applies especially in endemic areas.[1] However, early disease can be difficult to differentiate from other viral infections.[5] A probable diagnosis is based on the findings of fever plus two of the following: nausea and vomiting, rash, generalized pains, low white blood cell count, positive tourniquet test, or any warning sign (see table) in someone who lives in an endemic area.[23] Warning signs typically occur before the onset of severe dengue.[8] The tourniquet test, which is particularly useful in settings where no laboratory investigations are readily available, involves the application of a blood pressure cuff for five minutes, followed by the counting of any petechial hemorrhages; a higher number makes a diagnosis of dengue more likely.[8] It can be difficult to distinguish dengue fever and chikungunya, a similar viral infection that shares many symptoms and ...
Post a Comment
Read more

Research

Research efforts to prevent and treat dengue include various means of vector control,[43] vaccine development, and antiviral drugs.[27] With regards to vector control, a number of novel methods have been used to reduce mosquito numbers with some success including the placement of the guppy (Poecilia reticulata) or copepods in standing water to eat the mosquito larvae.[43] There are ongoing programs working on a dengue vaccine to cover all four serotypes.[27] One of the concerns is that a vaccine could increase the risk of severe disease through antibody-dependent enhancement.[44] The ideal vaccine is safe, effective after one or two injections, covers all serotypes, does not contribute to ADE, is easily transported and stored, and is both affordable and cost-effective.[44] As of 2009, a number of vaccines were undergoing testing.[13][33][44] It is hoped that the first products will be commercially available by 2015.[27] Apart from attempts to control the spread of the Aedes mosq...
Post a Comment
Read more