6.10.2: Endemic Diseases
Some diseases reach a level of regularity or seasonality, meaning they stay at a particular level consistently or only increase and decrease in a predictable pattern. Essentially, these illnesses remain with us at a consistent background rate, or cycle with predictable peaks every year. For example, we may become accustomed to “cold and flu season” that typically peaks between December and February in the United States (CDC, 2022). Since the numbers of cases increase up to the peak and then decrease in a predictable pattern over the course of those months, we would call the common cold and flu “endemic” to the U.S. Other pathogens are endemic to specific areas of the world, like malaria. Since mosquitos are the vector which transmits malaria to humans, malaria is endemic in many tropical countries where mosquitoes abound. Many virologists predict that COVID-19 will become endemic if it has not already (Jared, 2023).