To me, AIDS is an international epidemic and every country can be affected by it. Therefore, it can be discussed on an international level. Unfortunately, AIDS doesn't require a visa.
Without effective human intervention, epidemics and pandemics typically end only when the virus or bacteria has infected every available host and all have either died or become immune to the disease.
Left to their own devices, epidemic diseases tend to follow the same basic process: A virus or bacteria infects a host, who typically becomes sick and in many cases dies. Along the way, the host infects others.
As of 2013, according to the World Health Organization, 35 million people were estimated to be living with HIV or AIDS globally, and 39 million have died from the disease. The epidemic of denial won, and now everyone knows there is money in the making of drugs for AIDS.
Human bodies are designed for regular physical activity. The sedentary nature of much of modern life probably plays a significant role in the epidemic incidence of depression today. Many studies show that depressed patients who stick to a regimen of aerobic exercise improve as much as those treated with medication.
You can find episodes like the flu epidemic or war times when mortality rates go up, but sustained increases in mortality for any major group in any society are really quite rare. It's an indication that something is very wrong.
Online harassment, especially gendered online harassment, is an epidemic. Women are being driven out; they're being driven offline. This isn't just in gaming. This is happening across the board online, especially with women who participate in or work in male-dominated industries.