While getting sick could mean just a cold, a temporarily depressed immune system could also mean more severe illness too. (thehealthyhomeeconomist.com)
Shelter medicine is a huge challenge (understatement - stressed animals with depressed immune systems in close quarters) and animals who may not appear sick when leaving for a home may come down with symptoms shortly after leaving. (patriciamcconnell.com)
Sugar has been found to markedly depress the immune system, specifically the very parts involved in killing cancer cells before they become clinically apparent. (mindbodygreen.com)