Host defense mechanisms are imperfect because the genomes of every known virus encodes proteins that can block nearly every step of the immune response. For every host defense, there is a viral offense. Let’s consider the different ways that viruses are known to evade the early, or innate, host defenses. The illustration depicts in a …
In response to viral infection, many organisms mount a remarkable defense known as the immune response. This response to viral infection consists of an innate, or nonspecific component, and an adaptive, or specific defense. The innate response is considered the first line of immune defense because it is active even before infection begins. In fact, …
When influenza virus is introduced into the respiratory tract, by aerosol or by contact with saliva or other respiratory secretions from an infected individual, it attaches to and replicates in epithelial cells. The virus replicates in cells of both the upper and lower respiratory tract. Viral replication combined with the immune response to infection (which …
There is an ongoing outbreak of enterovirus 71 (EV71) in a broad region of Asia, including China, Vietnam, Mongolia, Taiwan, and Singapore. There have been 3606 cases in China, including 36 deaths. Infection with EV71 is common in Asia, where it causes hand-foot-and-mouth disease in children, a febrile syndrome accompanied by flat or raised red …
