The swine flu strain, called H1N1, is passed on just like seasonal flu—mainly through coughing or sneezing of infected people.
The symptoms also mirror those of seasonal flu, including fever, cough, sore throat, body aches, headache, chills, and fatigue.
Though H1N1 isn't a pandemic—the World Health Organization has given it a threat level of five, its second highest rating—it's much too early to tell how severe the outbreak will be, said Ruth Karron, director of the Center for Immunization Research at the Johns Hopkins Bloomberg School of Public Health.
"There probably will be additional deaths reported. We do [also] have deaths from seasonal influenza, and I think it's important to bear that in mind," Karron said.
As is possibly the case with H1N1, the elderly and young are most at risk for dangerous flu complications.
(Test your infectious disease IQ.)
Experts are most concerned about swine flu for three reasons, the public health association's Benjamin said.
For one, it's genetically novel from other viruses, meaning that people aren't resistant to it. The virus is also easily spread and has been very lethal in Mexico, where 159 people have died so far.
Even so, there are strategies to slow its progression, Benjamin said: Telling people to stay home if they develop flu-like symptoms, closing schools selectively, and practicing basic hygiene are all effective.
Johns Hopkins's Karron added that improved vaccine production capacity and antiviral drugs are available, unlike in previous pandemics.
"What's really important for people to understand is we have methods of mitigation," she said.
There are also better tools than ever before to diagnose and track the illness, the infectious disease foundation's Rehm added. For instance, local physicians are now armed with up-to-date information from government agencies.
"If it had to happen, we are as prepared as we can be," she said.
SOURCES AND RELATED WEB SITES