Why does listeriosis have high morbidity and mortality?

• A. Its endotoxin thrives in any aged animal and the organism can survive a wide range of temperatures/pH levels
• B. It rapidly mutates to evade immunity
• C. It is highly contagious between animals
• D. It only affects young animals

Answer: (A)

The main idea is that the pathogen’s ability to survive in a wide range of environmental conditions makes infection more likely and harder to control. Listeria can persist in foods and the environment across different temperatures and pH levels, including refrigeration, which means contaminated products can reach many animals. In aged or immunocompromised animals, even small doses can trigger a disseminated infection that involves the nervous system or the placenta, leading to severe illness and high mortality. This combination of environmental persistence and the capacity to cause systemic disease in vulnerable hosts explains why listeriosis can have such high morbidity and mortality. It isn’t mainly about rapid mutation to evade immunity, it isn’t primarily a highly contagious disease between animals, and it doesn’t exclusively affect young animals.