Dengue Fever

• Family: Flaviviridae
• Genus: Flavivirus
• Species: Dengue virus

• Arbovirus. Arthropod, Mosquito born (Aedes aegypti)



• It is a pathogen that causes Dengue fever (DF)
• Dengue hemorrhagic fever (DHF) can lead to Dengue shock syndrome (DSS)
• Has four different serotypes (DEN-1, 2, 3, 4)
• First reported epidemics in 1780 in Asia, Africa, and North America

• Affects humans
• It is prominent in tropical environments
• Ideal for mosquito habitats
• What is promoting the disease?
• Global warming is causing climate changes which is causing the disease to move to more environments
• Higher altitudes and amplitudes
• More habitats for mosquitoes to thrive in
• Spread has been increased by urbanization and population growth
• Inability of mosquito control in countries is also a major factor

• More than 2.5 Billion people live in areas that have a risk of infection
• Over 100 million cases of Dengue infection are reported each year globally
• 500,000 cases pertain to DHF
• DHF has a 5% fatality rate for those infected
• People at high risk are children and the elderly

Dengue induces cytokine production in cells

Cytotoxic factor affects endothelial cells in most of the following:

• Heart
• Liver
• Kidneys
• Lungs
• Intestines
• Spleen
• Lymph nodes
• Brain
• Skin (inflammatory rashes)

• Fever
• Headache
• Muscle and joint pain
• Dehydration
• Nausea and/or Haematemesis (vomiting of blood)
• Epistaxis (Bleeding from the nose, mouth, or gums)
• Haematuria (Blood in Urine)
• Pain behind the eyes
• Plasma leakage
• Respiratory distress
• Petechia (Skin rash) and/or Purpura (Lesions)

• Virus isolation by infection of mice using infected mosquitoes
• Detection of IgM antibodies in the blood by PCR or Viral isolation (Serology)
• ELISA (Enzyme-Linked Immunoabsorbent assay)
• Thrombopenia
• Raised hematocrit

• Humans are initially infected through a mosquito vector
• Initial interaction with cell occurs with the virus’s ability to infect cell
• Primary target are the phagocytes
• Virus uses cell receptor molecule to enter cell
• Cell receptor molecules include:
• Glycosaminoglycan
• Heparan Sulfate (Expressed in almost all cell types)
• Virus replicates in target organs
• Infects white blood cells and lymphatic tissues
• Virus is released and circulates in blood
• Alternate mosquito then bites host and receives virus

There is no specific treatment

Relieving symptoms and complications:

• Plasma volume replacement
• Sedatives for restless patients
• Blood transfusion with patients with significant blood loss
• Aspirin should be avoided

• Efforts of control are aimed against mosquitoes
• Elimination of breeding areas
• Actions to prevent mosquito bites (repellant, nets, and vapors)
• Vaccines
• Problem is that the vaccination needs to prevent all four serotypes
• Dengvaxia is the only dengue vaccine approved by the U.S. Food and Drug Administration and recommended for routine use by the Advisory Committee on Immunization Practices. It is made by Sanofi Pasteur. The vaccine prevents dengue caused by all four dengue virus serotypes.
• The vaccine is a tetravalent, live-attenuated dengue vaccine. It was constructed using recombinant DNA technology and replaces several genetic sequences in a yellow fever vaccine virus genome with the homologous sequences from the four dengue virus serotypes.