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LWhen pathologist Thijs Kuiken examines the U.S. response to the H5N1 bird flu outbreak in dairy cows, he recalls a difficult time in the Netherlands, where he lives, in the late 2000s.
From 2007 to 2010, large goat and sheep farms were affected by annual outbreaks of Q fever. The disease, caused by the bacterium Coxiella burnetii, mainly affects ruminants (sheep, goats and cows). But humans can also get it. Some do not get sick. Some get a flu-like illness and recover. But some develop chronic Q fever syndrome, a debilitating disease. Hundreds of people in the Netherlands still suffer from the disease following the outbreaks of 2007-2010.
Scientists fear that the H5N1 virus could one day trigger a pandemic. Q fever is a bacterial disease that, when present in an environment, can cause significant numbers of infections in humans. But Kuiken sees a similarity in how, in both cases, the initial tendency is to treat these events in animals as an economic problem for the agricultural sector, rather than as an agricultural problem that could also have serious consequences for human health.
“My general concern about this outbreak is that it is too often treated as an economic problem and not enough as a public health and animal health problem,” said Kuiken, who works in the department of viroscience at Erasmus Medical Center Rotterdam.
Kuiken is one of the flu experts STAT spoke to last week for a story analyzing the response to the H5N1 outbreak in cows so far. He and others are concerned about the lack of urgency in the U.S. response and the apparent absence of a comprehensive plan to eradicate the virus from livestock. Agriculture Secretary Tom Vilsack believes the answer lies in better biosecurity on farms. But with the number of affected farms continuing to rise (the number reached 139 in 12 states as of late last week, and those are farms where farmers have actually authorized testing) there’s no sign that the trend is reversing. (The USDA’s count was 133 on Friday, which didn’t include the two most recent detections in Iowa and the four most recent in Colorado.)
Allowing the H5N1 virus to establish itself in cows would give the virus a chance to adapt to a mammalian species, increasing the risk that it would acquire mutations that would allow it to spread to and among humans.
The response to the Q fever outbreaks has been similar, Kuiken said: “Initially it was mainly an economic problem and a dairy goat industry problem, and it was handled by the Ministry of Agriculture.”
Infected animals shed large amounts of the bacteria in their milk, urine, feces and placentas. The infections caused “abortion storms” on farms where pregnant animals were kept, Kuiken said. The bacteria were blown away by the wind. “People were riding their bikes past these farms and getting infected.” But the locations of the affected farms have not been publicly disclosed, due to privacy concerns. (Sound familiar?) “So even though people were worried about getting infected and wanted to stay away from these areas, they didn’t know where they were,” he said.
The country’s health minister eventually called for the outbreak to be treated as a human health issue as well. “This was really an important lesson for veterinary and medical authorities,” Kuiken said.
Currently, control of the response to the H5N1 outbreak is in the hands of the U.S. Department of Agriculture. While many cases of sick farm workers have been reported (far more than the three people who have tested positive for H5N1 in this outbreak so far), few have been tested. The Centers for Disease Control and Prevention reported Friday that at least 53 people have been tested for the virus since the outbreak was first detected. That number was up from 51 late last week.
Efforts to try to determine the number of people infected have been thwarted because in many cases farmers have refused to let public health officials onto their properties to talk to and test their workers. But finally, there is a breakthrough: Michigan health officials are conducting a small serology study, with the cooperation of an undisclosed number of farms in the state. Participating workers fill out questionnaires describing their encounters with cows and their daily tasks, and give a blood sample that will be tested for antibodies to the virus. The CDC is collaborating with Michigan on the study.
Another ongoing study is the second part of an effort by the Food and Drug Administration (FDA) to assess the risk that the H5N1 virus poses to commercial dairy production. In early May, the agency reported that of nearly 300 samples of store-bought milk, about 1 in 5 contained fragments of avian flu viruses, but the viruses had been killed by pasteurization. (The FDA and USDA on Friday released a preprint — a study that has not yet been peer-reviewed — showing that commercial pasteurization techniques reduce the virus in milk to undetectable levels.)
The second part of the milk study will focus on some dairy products not tested in the first iteration, Don Prater, acting director of the FDA’s Center for Food Safety and Applied Nutrition, told reporters last week. Those include cream cheese, raw-milk aged cheese, butter and ice cream. Results will be available in a few weeks, he added.
The USDA will soon begin accepting applications for assistance to help farmers offset lost income from reduced milk production from cows infected with the H5N1 virus. With money available to cover losses, it is hoped that farmers will finally find a reason to test animals they suspect may be infected with the virus.