Dengue virus

Definition

Dengue virus is an arthropod-borne virus (arbovirus) that is responsible for causing dengue fever, a tropical disease transmitted primarily by Aedes mosquitoes. This virus is part of the Flavivirus genus and has four distinct serotypes, leading to the potential for severe disease upon reinfection. Understanding how dengue virus infects hosts and the immune responses it elicits is crucial for controlling outbreaks and developing effective vaccines.

5 Must Know Facts For Your Next Test

1. Dengue virus is transmitted to humans through the bite of infected Aedes mosquitoes, mainly Aedes aegypti and Aedes albopictus.
2. Infection with one serotype of dengue virus provides lifelong immunity against that specific serotype but increases the risk of severe illness if infected with a different serotype.
3. Symptoms of dengue fever typically appear 4 to 10 days after being bitten by an infected mosquito and can include high fever, rash, and severe pain.
4. Severe forms of dengue, such as dengue hemorrhagic fever and dengue shock syndrome, can be life-threatening and require urgent medical attention.
5. Preventive measures against dengue virus include mosquito control strategies, use of insect repellent, and vaccination with Dengvaxia in certain populations.

Review Questions

• How does the transmission cycle of dengue virus involve its mosquito vectors and human hosts?
  • The transmission cycle of dengue virus begins when an Aedes mosquito bites a human who is already infected with the virus. The mosquito then becomes a carrier, as the virus replicates within it. When the infected mosquito bites another person, the virus enters their bloodstream, potentially leading to dengue fever. This cycle underscores the relationship between the mosquito vectors and human hosts in the spread of the disease.
• Discuss the implications of having four distinct serotypes of dengue virus for public health strategies aimed at controlling outbreaks.
  • Having four distinct serotypes of dengue virus complicates public health strategies because infection with one serotype does not confer immunity against the others. This means that individuals can be infected multiple times throughout their lives. Public health efforts must focus on comprehensive surveillance and control measures that take into account this complexity, including education about risks associated with reinfection and development of vaccines that provide broad protection against all serotypes.
• Evaluate the role of immune response in both protection and risk during subsequent infections with different serotypes of dengue virus.
  • The immune response plays a dual role in dengue infections. Upon first exposure to one serotype, individuals develop immunity to that specific strain. However, if they are later infected with a different serotype, their immune system may respond inappropriately due to antibody-dependent enhancement (ADE). This phenomenon can lead to more severe disease manifestations like hemorrhagic fever or shock syndrome. Thus, while the immune system generally protects against infections, it can paradoxically increase the risk of severe outcomes upon secondary infections.

Related terms

Aedes mosquitoes: Aedes mosquitoes are a genus of mosquitoes known for being the primary vectors of dengue virus, as well as other diseases such as Zika and chikungunya.

Dengue fever: Dengue fever is an acute febrile illness caused by dengue virus, characterized by high fever, severe headaches, pain behind the eyes, joint and muscle pain, and rash.

Serotypes: Serotypes refer to distinct variations within a species of bacteria or viruses that can induce different immune responses; dengue virus has four serotypes, labeled DEN-1 through DEN-4.