Zoonosis: who is at risk?
Not every zoonose infection leads to illness. People in good health (read: with a strong immune system) can be carriers of disease without becoming ill themselves. This same dynamic is at work in other populations at higher risk, where the infection can be more serious. The term used to refer to these groups as a whole is YOPI: Young, Old, Pregnant or Immunocompromised.
The Young are, of course, children and -- especially -- babies, as their immune systems are not yet fully developed. The effects of illness can also be more serious in babies. Diarrhoea can easily lead to dehydration.
The Old are seniors, fragile because their immune systems no longer function optimally.
The Pregnant are at special risk because the immune system of an expectant mother can be less effective. The biggest problem here, however, is that some pathogens can pass through the placenta to cause damage to the unborn child, even if the mother isn’t sick herself. Factors influencing the risk to an embryo or foetus are the characteristics of the specific pathogen and how advanced the pregnancy is.
The Immunocompromised are those with a weakened immune system. The problem can be caused by an illness such as HIV, or taking medicines that suppress the immune system (after an organ transplant). Chemotherapy and radiation administered to treat cancer also have an immunosuppressant effect.