The odd case of flu contracted from a pig poses no broad public health risk, as this variety has no track record of spreading from person to person.
Buried in recent flu data from federal health officials is news that a Mercer County child had a type of swine flu transmitted from a pig, instead of from another person.
While such cases are not common, they are monitored by the government in case they become more widespread.
The case of what's called H3N2v flu - the state's first - involved a 9-year-old child from Mercer County who visited a Middlesex County farm on Dec. 24 of last year and fell ill Dec. 26th.
The child's illness was mild and did not require hospitalization, according to a spokeswoman for the N.J. Department of Public Health. The child was treated by a healthcare provider.
The U.S. Centers for Disease Control and Prevention indicated,"The patient visited a farm near where swine are frequently housed but no direct contact with swine was reported in the week prior to illness onset."
The illness that people call "swine flu," which was epidemic in 2009, comes from a virus with slight genetic variations that allow it to move more easily from pigs to humans. Once in humans, it is capable of human-to-human transmission.
In the recent New Jersey case, however, "no ongoing human-to-human transmission has been identified," according to the CDC report.
"There is no public health risk. No additional cases of illness have been reported among the child's family," said Nicole Mulvaney of the N.J. Department of Health.
By contrast, H3N2v (the 'v' stands for "variant") has never been a widespread problem, said Henry Niman, a Pittsburgh-based virologist who consults on swine flu and other related viruses.
"In 2012, it really looked like it could become a significant issue," he said, when there was a spike of hundreds of cases nationally. One woman in Ohio died from the illness. However, cases of the virus then died down, returning to just a handful of cases a year.
Since 2005, there have been just 354 confirmed cases of H3N2v, with the lion's share of them reported in Ohio and Indiana.
While this flu variation can be caught from pigs, its main way to spread remains person-to-person, Niman said. He cited a cluster of cases out of Washington County, Pennsylvania in which a number of people got sick after attending a county fair.
Many were 4-H members or their relatives - in other words, people who had spent substantial time around the pigs being exhibited. When public health officials subsequently interviewed their close contacts, they discovered hundreds of cases of suspected flu passed from person to person, Niman said.
Because this occurred in August, few viewed their mild, flu-like symptoms as actual "flu."
"Some were infected by swine, but most were infected by other family members," he said. "It's more of a risk to be around farmers than to be around pigs."
The N.J. Department of Health offers this advice about swine flu variants:
"To protect against the H3N2v flu virus (and other flu viruses), residents should limit contact with live pigs and wash hands with soap and water after exposure to live animals. If an individual recently had exposure to a live pig, they should monitor themselves for flu symptoms, which include fever, cough, extreme fatigue and lack of appetite. Residents who have had contact with live pigs and are experiencing these symptoms should notify their healthcare provider."
Kathleen O'Brien may be reached at kobrien@njadvancemedia.com. Follow her on Twitter @OBrienLedger. Find NJ.com on Facebook.