Latest Infectious Disease News
A respiratory virus that recently sickened more than 200 people in China has appeared for the first time on U.S. soil. An American man in the Seattle area returned home last week with the recently discovered viral infection after visiting Central China, the CDC confirmed Tuesday.
First reported in Wuhan, China in December, the virus “2019 novel coronavirus” (“2019-nCoV”) was identified and named last week. It was identified as a coronavirus, placing it in a virus group that includes the deadly SARS and MERS infections.
As of Tuesday, infections from 2019-nCoV have claimed six lives and infected 291 people in China, the Associated Press reports. Other cases have been reported in South Korea, Japan, Thailand, and Taiwan.
Here are five important facts to catch you up to speed on this deadly new disease.
What Is Coronavirus, and Why Is It Named That?
“Coronavirus” refers to a group of RNA viruses, according to MedicineNet author and editor William C. Shiel Jr., MD, FACP, FACR. They got their name for their halo or corona-like appearance when viewed under an electron microscope, he explained.
These viruses are the second-leading cause of the common cold. But some strains of the virus, including SARS and MERS, have caused more serious health problems, as well as death.
What Makes Coronaviruses Unique?
“Coronaviruses are very unusual viruses,” Dr. Shiel said. One reason is they are “gigantic” by virus standards, he said, possessing over 30,000 nucleotides.
They also replicate in an unusual way, using a two-step replication mechanism. While many RNA viruses have a single, large gene that is replicated in a host’s body to produce viral proteins, coronaviruses may have as many as 10 separate genes, Dr. Shiel said.
“The coronavirus genome is a single strand of RNA 32 kilobases long and is the largest known RNA virus genome,” Dr. Shiel said. “Coronaviruses are also unusual in that they have the highest known frequency of recombination of any positive-strand RNA virus, promiscuously combining genetic information from different sources.”
How Are Coronaviruses SARS and MERS Different?
The new virus identified in China last week—2019-nCoV—is not SARS (“severe acute respiratory syndrome”), though both are coronaviruses. As such, both share some characteristics. SARS caused one of the most deadly coronavirus outbreaks on record. SARS was first identified in April 2003 by the CDC. In the 2002-2003 SARS outbreak, an estimated 10% of those infected (774 people) later died, according to Sandra Gonzalez Gompf, MD, FACP.
“SARS-CoV virus had never been identified before 2002,” Dr. Gompf said. “This was not entirely surprising because there are many types of coronaviruses, and they are known to mutate easily.”
Another deadly acute respiratory disease caused by a coronavirus is MERS (“Middle East respiratory syndrome”). MERS was first identified in 2012.
How Are Coronaviruses Transmitted?
Coronaviruses are commonly spread by animals. According to the World Health Organization, a detailed investigation revealed in 2002 that civet cats were responsible for SARS infections in humans. In 2012, MERS was linked to dromedary camels in Saudi Arabia. Bats are also believed to be common carriers of coronaviruses.
“Several known coronaviruses are circulating in animals that have not yet infected humans,” the WHO states. “As surveillance improves around the world, more coronaviruses are likely to be identified.”
Coronavirus infections can cause a variety of health problems in animals, Dr. Shiel said. These include hepatitis (inflammation of the liver) in mice, gastroenteritis (inflammation of the digestive system) in pigs, and respiratory infections in birds.
Although animals are common carriers, some coronavirus infections are also spread from person to person. That was true during the SARS outbreak. During the SARS outbreak, an estimated one in 20 infected people was a health care worker caring for a patient with SARS, Dr. Gompf said.
How Are Novel Coronaviruses Treated? Is There a Vaccine?
Since it is new, no vaccine has been developed for 2019-nCoV so far. Developing a new vaccine can take “a number of years,” according to the WHO.
The Chinese government faced criticism by some for responding slowly to the SARS health crisis in 2003. To act quickly, last week Chinese scientists published the genome sequence of 2019-nCoV with an eye toward sourcing a vaccine or treatment.
No individual treatment has been developed yet for this new virus. However the symptoms of a respiratory infection can be treated. The WHO adds that supportive care for infected people can be “highly effective.”
Meanwhile, to protect yourself, the WHO recommends:
- Maintaining basic hand and respiratory hygiene
- Maintaining safe food practices
- Avoiding close contact, when possible, with anyone showing symptoms of respiratory illness, such as coughing and sneezing.