The U.S. Centers for Disease Control and Prevention said Thursday afternoon that the infected man was on a pre-extraction program and was helping to remove the chickens from an infected farm. The man, who was under 40, reported fatigue for a few days but has recovered, state health and CDC officials said in a statement. The man was isolated and treated with antiviral drug. Other people involved in the Colorado birdwatching operation tested negative, but are being re-screened for a lot of attention. The man was part of a crew of inmates approaching release who were working on the farm before a bird flu outbreak was confirmed there on April 19, said Lisa Wiley, a spokeswoman for the Colorado Department of Corrections. When bird flu was detected on a farm in Montrose County, detainees were asked to help kill and repel the birds. Agriculture officials reported an outbreak on a Montrose County farm with 58,000 chickens. Despite the infection, the CDC considers the threat to the general public to be low because the spread of the virus to humans requires close contact with an infected bird. Signs that could increase the risk to public health may include multiple reports of viral infections in people from bird exposure or recognition of spread from one person to another. The CDC is also monitoring genetic changes in the currently circulating H5N1 bird flu virus. Any genetic changes could indicate that the virus adapts to spread more easily from birds to humans or other mammals. Many different avian influenza viruses have been infecting humans around the world since at least the 1990s, but health officials still say that human infection is uncommon. In 2002, H7N2 caused pink and mild respiratory symptoms in people in the United Kingdom and the United States. Four infections in the United States have been detected since 2002. Two were transmitted from cats to humans in 2016. More than 1,500 people in China have been infected with the H7N9 strain, largely in cases between 2013 and 2017. This version caused serious infections in humans and 40% of those treated died. A different variant of H5N1 has also been available since 1997, infecting more than 880 people and having a 50% mortality rate. The current variant of H5N1 spreads to chicken and turkey herds in the US. in the backyard and in the trade swarms from the end of February. Viruses have been found in commercial birds and birds of prey in 29 states and in wild birds in 34 states. More than 35 million chickens and turkeys have been killed and removed to prevent the spread, the US Department of Agriculture said. The CDC said it had monitored the health of more than 2,500 people exposed to H5N1-infected birds, but that the detainee’s illness was the only confirmed case to date. The agency said it was possible the man only had the virus in his nose and that his body was not infected. Colorado public health officials say repeated tests on the man were negative for the flu. A positive nasal smear test meets the body’s criteria for treating it as an infection. “The appropriate response to public health at this time is to assume that this is an infection and to take action to limit and treat it,” the CDC said in a statement.
