Medical workers in protective gear talk with a woman suspected of being ill with a coronavirus at a community health station in Wuhan in central China's Hubei Province, Monday, Jan. 27, 2020. China on Monday expanded sweeping efforts to contain a viral disease by extending the Lunar New Year holiday to keep the public at home and avoid spreading infection. (Chinatopix via AP) Credit: Courtesy of Chinatopix via AP

As New Hampshire monitors two possible cases of coronavirus, the risk of the novel infection spreading in Maine is low, according to the director of the state’s Center for Disease Control and Prevention.

However, the new coronavirus strain has spread internationally in a few weeks, with the number of confirmed cases rising nearly 60 percent between Monday and Tuesday alone. And the outbreak is happening during what has already been a more intense flu season in Maine that has led to more hospitalizations and deaths than last year.

There is a lot still unknown about the coronavirus as national and global health agencies and experts track the evolving outbreak. And that’s part of what makes the infection so worrying to public health authorities trying to limit its spread.

“What makes anything dangerous is you don’t know anything about it,” said Ronald Corley, director of the National Emerging Infectious Diseases Laboratories and a professor of microbiology at Boston University. “It just spilled over into the human population at the end of 2019. We don’t know really anything about it. We don’t necessarily know what to expect when a person gets the novel coronavirus.”

The first coronavirus infections were identified in the city of Wuhan in central China in December 2019. Within weeks, the virus spread across China and to at least 18 other countries, including the U.S. and Canada.

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As of Wednesday, 132 people had died from the virus, and the number of confirmed cases had risen to 5,974, with the overwhelming majority in China, The New York Times reported. No international deaths have been reported yet.

Across the U.S., 165 people were being monitored for the coronavirus, the U.S. CDC said Wednesday. Of those, five had confirmed infections, with the majority — like those in New Hampshire — still awaiting test results.

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But worldwide, the size of the outbreak is likely larger than the number of confirmed cases. A Northeastern University virus spreading estimate puts the size of the outbreak at 26,200 infections. And a transmissibility report by MRC Centre for Global Infectious Disease Analysis at Imperial College in London says that each infected person is estimated to have spread the virus to roughly two to three other people by Jan. 18.

In New Hampshire, the two people being monitored developed respiratory symptoms after recent travel to Wuhan. They are in isolation and are undergoing testing, according to the New Hampshire Department of Health and Human Services .

Credit: Chiang Ying-ying | AP

The new coronavirus isn’t a specific infection. It is a new strain within the coronavirus family that has caused past global outbreaks.

Coronaviruses can cause diseases ranging from the common cold to more severe infections. They are found in many different species of animals. Some evolve and infect humans, and have affected large numbers of people before, including the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) — which infected 8,000 people and killed 800 in 2003 — and the Middle East respiratory syndrome coronavirus (MERS-CoV), according to the CDC.

There are seven types of coronaviruses that have been known to infect people and cause illnesses. China reported the novel coronavirus, temporarily named the 2019-nCoV, to the World Health Organization on Dec. 31.

In a report published Monday, the WHO classified the risk of coronavirus as high globally, and very high in China. It has also published technical guidance for health experts for treating suspected novel coronavirus (nCoV) infections.

Infected people can show a range of flu-like symptoms, but patients without symptoms can also transmit the virus.

Infected people so far have exhibited a range of conditions, from few to no symptoms to severe illness and death. The CDC has listed cough, fever and shortness of breath as known symptoms.

The symptoms of 2019-nCoV may appear as soon as two days after exposure or as long as 14 afterward, the CDC estimates based on the incubation period of the MERS coronavirus.

“Individuals that have the coronavirus and the flu virus show very much the same symptoms,” Corley said. “That’s why [health professionals] are monitoring people carefully because that’s the only way to prevent spread. To identify potential contacts, keep them restricted in their movement by quarantining and then waiting until you get the diagnostics on them.”

The WHO recommends hand and respiratory hygiene and sound food safety practices as preventative measures for the public.

There is evidence that the new virus has spread from person-to-person contact. However, many early patients in Wuhan had some link to a large seafood and live animal market, suggesting an animal-to-person spread, according to the CDC.

“There have been some reports that even asymptomatic people, people who don’t have symptoms, can in fact transmit the virus,” Corley said. “If you don’t have symptoms, it doesn’t mean you’re not going to pass it on. Being cautious given how quickly this has spread to other countries is probably the best approach.”

Credit: Eugene Hoshiko | AP

China has implemented travel shutdowns and quarantines, and health organizations across the world are monitoring potential cases.

The Chinese government shut down all modes of transportation from Wuhan, including flights, buses, trains and ferries, to contain the outbreak, The New York Times reported. Last week, cities near Wuhan as well as China’s capital, Beijing, announced additional quarantines.

“The primary issue is to limit human-to-human transmission, to reduce secondary infections, especially amongst close contact and particularly in healthcare environments,” Dr. Michael Ryan, the WHO’s head of emergencies, said in an emergency meeting about the novel coronavirus on Jan. 22.

Ryan also said that reducing transmission from animals to humans, identifying the animal source or sources, and limiting exposure to those sources were priorities.