Sapovirus Infections in Nursing Homes Spreading in U.S.: Study

A little known and once-rare stomach bug is beginning to spread in nursing homes and long-term care centers throughout the United States, according to a new report. 

Researchers have noticed a prevalence of gastroenteritis outbreaks, which would usually be attributed to norovirus, but norovirus was not detected.

A new report by the U.S. Centers for Disease Control and Prevention (CDC) looked at a number of outbreaks in Oregon and Minnesota, and found that many were caused by sapovirus IV, considered a cousin of norovirus. However, it is on the rise and is increasingly causing illness and death in institutional settings, the researchers noted.

Fecal samples from 93 outbreaks at nursing homes and long-term care facilities in Oregon and Minnesota from 2002-2009 were tested by researchers. They found that 21 were linked to sapovirus.

Researchers say that it appears that sapovirus infections surged in 2007 worldwide. Before that only 3% of sapovirus outbreaks were detected in the elderly, and usually in individual instances instead of multi-victim outbreaks.

Sapovirus and norovirus are members of the bacterial family Caliciviridae, which was first discovered in 1977. It has a 24 to 48 hour incubation period and the most common symptom is vomiting that lasts from 12 to 60 hours. Sapovirus got its name from the first outbreak in a home for infants in Sapporo, Japan and was generally associated with outbreaks among young children.

Norovirus is extremely contagious and causes gastroenteritis. Symptoms of gastroenteritis from norovirus in humans can include nausea, vomiting, diarrhea, stomach cramping and sometimes low-grade fevers, chills, headaches, muscle aches and tiredness. The symptoms hit suddenly, and last for about several days.

Researchers recommended that future investigation of gastroenteritis outbreaks be investigated using multi-organism testing methods. Their findings were published ahead of print in the U.S. Centers for Disease Control and Prevention (CDC) medical journal Emerging Infectious Diseases.