January 11, 2013

Three separate flu or flu-like epidemics are emerging simultaneously across North America. The first includes an unusually aggressive flu virus that is showing up earlier than usual. The second is a surge of cases from a new type of norovirus. The third is a whooping cough outbreak, the worst in 60 years.

Forty-seven states reported that the flu had become widespread during the week ending January 5, up from 41 states the previous week, the Centers for Disease Control and Prevention (CDC) announced today. The most common strain currently moving across the county is an H3N2. This strain is more lethal than H1N1, the strain that typically appears in the United States at this time of year. The number of flu cases is currently “elevated” across the United States, except in Arizona, California, Hawaii, and Nevada. However, 24 states and New York City have reported “high levels” of flu-like illness to the CDC. On January 9, the mayor of Boston declared a public health emergency because of the number of flu cases flooding the city’s hospital emergency rooms. Across the United States, more than 3,700 people, primarily senior citizens, have been hospitalized with the flu and at least 20 children have died from the H3N2 strain since the season began this fall.

Cities across Canada have reported outbreaks of norovirus so serious that hospitals are shutting down and disinfecting whole wards because patients were becoming infected after checking in with a different ailment. The new strain is known as the Sydney 2012 variant, because it first appeared in Australia. The classic symptoms are “explosive” diarrhea and “projectile” vomiting.

Flu is caused by a virus, such as the ones above, which have been greatly enlarged and artificially colored. (© Linda Stannard, UCT/SPL from Photo Researchers)

In early January, the CDC reported 42,000 confirmed cases of whopping cough in the United States in 2012, the biggest outbreak in  60 years. The disease is unrelated to flu but causes a hacking, constant cough and breathlessness. Infants, especially premature infants, are at greatest risk. There were 18 recorded deaths from whopping cough in the United States in 2012.

The CDC and the local health authorities strongly advocate getting flu shots. Based on data from some 1,155 children and adults with acute respiratory infections, flu vaccines are judged to be 62-percent effective. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University in Nashville, Tennessee, has characterized this level of effectiveness as “normal.” “It’s a good but not a perfect vaccine,” he noted.

Additional World Book articles:

• Spanish flu
• Swine Flu
• Disease Detectives (a special report)
• Influenza: A New Threat from an Old Foe (a special report)
• Public health 2009 (a Back in Time article)