What does it mean when a virus is virulent?
Definition. A virus that lyses its host immediately upon infection and often cause disease. Supplement.
What virulence factors do viruses have?
Viral virulence is influenced by viral genes in four categories: (1) those that affect the ability of the virus to replicate, (2) those that affect host defense mechanisms, (3) those that affect tropism, spread throughout the body and transmissibility, and (4) those that encode or produce products that are directly …
Can dengue virus be killed?
Typical dengue is fatal in less than 1% of cases; however, dengue hemorrhagic fever is fatal in 2.5% of cases. If dengue hemorrhagic fever is not treated, mortality (death) rates can be as high as 20%-50%. Luckily, if you’re planning on traveling, a vaccine is available.
What are four types of dengue virus?
Dengue is caused by a virus of the Flaviviridae family and there are four distinct, but closely related, serotypes of the virus that cause dengue (DENV-1, DENV-2, DENV-3 and DENV-4). Recovery from infection is believed to provide lifelong immunity against that serotype.
What causes high virulence?
Virulence—the harm a pathogen does to its host—can be extremely high following a host shift (for example HIV, SARs and Ebola), while other host shifts may go undetected as they cause few symptoms in the new host.
What is an example of virulent?
What is an example of a virulent? Human immunodeficiency virus or HIV is an example of a virulent virus. It is the causative agent of AIDS. It is virulent because it employs mechanisms for evading the host immune cells.
What is virulent and non virulent?
F protein of virulent strains is cleaved into the subunits Fi and F2 (Figure 1) by ubiquitous host proteases found in most tissues, whereas the F protein of non-virulent strains is cleaved only in cells containing trypsin-like enzymes. This enables virulent strains to spread faster within the host.
Can dengue happen twice?
It is possible to get dengue more than once. Dengue is caused by a virus which has four different strains. Being affected by one strain offers no protection against the others. A person can suffer from dengue more than once in her/his lifetime.
Is flavivirus enveloped?
The Flaviviridae are a family of positive, single-stranded, enveloped RNA viruses. They are found in arthropods, (primarily ticks and mosquitoes), and can occasionally infect humans.
What is serotype in dengue virus?
The Dengue Serotypes Dengue infections are caused by four closely related viruses named DEN-1, DEN-2, DEN-3, and DEN-4. These four viruses are called serotypes because each has different interactions with the antibodies in human blood serum.
What is high virulence?