Infectious disease
8 questions tagged Infectious disease — spanning every one of the seven Ws.
What is measles?
Measles is a highly contagious viral disease that causes fever, cough, red eyes, and a characteristic rash. It can lead to serious complications such as pneumonia and brain inflammation.
Which vaccine was the first widely used vaccine against a bacterium that causes stomach ulcers?
There is no licensed vaccine for Helicobacter pylori, the bacterium that causes many stomach ulcers, so no vaccine is widely used against it. This makes it a notable exception among major infectious causes of disease.
Which vaccine is most important for preventing pneumonic plague outbreaks?
There is no routinely used plague vaccine for the general public, so no vaccine is currently the main tool for preventing pneumonic plague outbreaks. Public health control relies on antibiotics, surveillance, and vector control.
Why do antibiotics not work against viruses?
Antibiotics target structures that bacteria have, such as cell walls and bacterial ribosomes, but viruses do not have those same targets. That is why antibiotics do not treat colds, flu, or COVID-19.
Why can one measles case start a large outbreak?
Measles is one of the most contagious human infections, with an R0 often estimated around 12 to 18. In a community with low vaccination coverage, a single case can spread very rapidly.
Why does tetanus cause muscle spasms instead of a typical wound infection?
Tetanus is caused by a toxin made by Clostridium tetani, not by the wound itself spreading locally. The toxin blocks nerve signals that normally relax muscles, leading to painful spasms.
Why do some diseases spread through the air more easily than others?
Airborne spread is more likely when a germ survives in tiny particles that stay suspended and can be inhaled. Factors like particle size, moisture, ventilation, and how much virus a person sheds all matter.
How do antibiotics work against bacterial infections, and why do they not work on viruses?
Antibiotics attack bacterial structures or functions that human cells do not have, such as cell walls or specific enzymes. Viruses do not have those targets, so antibiotics do not affect them.