This month's biggest news topic has expanded awareness of health terms that may be fuzzy or unfamiliar, such as the word pandemic (pronounced pan-DEMM-ick). The World Health Organization, a United Nations agency based in Geneva, Switzerland, last week declared that the coronavirus known as COVID-19 is a global pandemic -- a disease epidemic that has spread to all continents except Antarctica. Earlier examples include Spanish flu in 1918, smallpox, tuberculosis, HIV/AIDS and a 2009 flu pandemic. (Epidemic is a lower-level designation for above-normal cases of an illness, generally limited to one community or region.)

The current virus, which causes breathing difficulty, was first identified in Wuhan, China, in late December. More than 130 countries, with major outbreaks in central China, Italy, South Korea and Iran. More than 7,000 people have died from the disease and over 78,000 have recovered. Roughly 4,100 Americans are confirmed to be affected, a number sure to rise as free public testing expands widely this week, and at least 40 have died. The spread of pandemics can be slowed, but not stopped quickly. Once a new disease reaches that level of transmission, there's no way to halt the spread completely until a vaccine is developed. Still, medical care is much better than 100 years ago, and a scientists worldwide are working to unlock the secrets of COVID-19 so doctors can provide protective injections similar to annual flu shots.

Pandemics can be mild, or severe, depending on the disease itself. The most recent pandemic before now was the global spread in 2009 of an influenza type called H1N1. Although it formally reached pandemic levels by spreading across the globe, the disease had a mild impact in many countries. From April to November that year, about 3,900 people died in the United States from the H1N1 virus, a figure considered relatively low.

WHO doctor says: "’Pandemic’ comes from the Greek 'pandemos,' which means everybody. 'Demos' means the population. 'Pan' meaning everyone. So 'pandemos' is a concept where there's a belief that the whole world's population will likely be exposed to this infection and potentially a proportion of them fall sick." -- Dr. Mike Ryan in Geneva

U.S. specialist says: "Although we are far more prepared than in the past, we are also far more interconnected, and many more people today have chronic health problems that make viral infections particularly dangerous." – Dr. Tom Frieden, former director of the federal Centers for Disease Control

1918 pandemic: Influenza sometimes referred to as Spanish flu infected an estimated 500 million people (one-third of the world's population then) and is believed to have killed about 50 million. More American soldiers died from the pandemic than in World War I during 1918.