Jan. 23 2024 09:04 AM

With contributions by Jason Lombard, D.V.M.; Stephanie Ringler, D.V.M.; Natalie Urie, D.V.M.; James Sunstrum, M.D.; and Hind Hadid, M.D.

The authors are a Connecticut dairyman, veterinarians with USDA’s Veterinary Services, and infectious disease physicians with Corewell Health Hospital in Michigan, respectively.

I’ve been a dairy farmer for almost 50 years, and as many in the industry know, farm work must be completed even when you’re at your worst. That was true for me until I began experiencing extreme fatigue, headaches, and chronic bone and muscle pain in my legs and hands that left me bedridden some days. This was followed by shortness of breath, which lasted for two months where it was very difficult to even talk.

The symptoms I was experiencing are what I would imagine an extreme case of Lyme disease to feel like. For over a year, I met with multiple doctors who had no answers while my symptoms continued. Finally, I was referred to an infectious disease doctor who ran several tests to see if we could find the root of the problem.

Uncovering the cause

In 2022, I was diagnosed with a disease called chronic Q fever, which is caused by the organism Coxiella burnetii. I found that Q fever is a zoonotic disease, meaning that it is transmissible between animals and humans. People can be exposed in a few different ways, including the consumption of contaminated raw milk and contact with an infected animal’s feces, blood, placenta, or birthing fluids.

Since I stopped drinking raw milk more than two decades ago, the most likely route of transmission in my case was while I assisted cows during calving. I was told Q fever is an extremely rare disease and likely no doctor in the United States has diagnosed it in even two patients.

Q fever isn’t a hot topic among veterinarians and dairy producers because it rarely causes noticeable clinical signs in animals. Most human infections are associated with small ruminants, but cattle can be a source of infection, along with cats, dogs, ticks, and other animals. In cattle, sheep, and goats, the infection is called coxiellosis.

Infected livestock may shed Coxiella organisms in their milk, urine, feces, and birthing fluids. Infected pregnant ruminants can shed high numbers of this organism at birth or during an abortion, especially in the amniotic fluid and the placenta, which are expelled during the birthing process. This excessive shedding poses a high risk of exposure to other animals and humans.

The disease is associated with late pregnancy abortions, stillbirths, and early neonatal mortality in sheep and goats. U.S. seroprevalence studies found almost a quarter of goat operations and 12% of sheep operations had evidence of current or past Coxiella burnetii infection, while research from Canada showed about half of sheep and goat operations had been exposed.

Difficult to detect

Could your cows be infected with Coxiella? The answer is likely yes.

Cattle usually don’t show any clinical signs of disease. Three U.S. studies conducted in the early 2000s evaluating bulk tank milk found that between 80% and 95% of farms had evidence of previous coxiellosis infection, with larger farms more likely to have evidence of infection. Managing the disease in cattle is difficult, and no vaccines are currently available in the United States. People working with cattle are the most likely to be impacted by the disease.

In the United States, cases are reported based primarily on human and/or animal laboratory diagnosis of active infections or reports from producers and/or private veterinary practitioners. In livestock, the USDA definition of a suspect case of coxiellosis includes an “abortion storm in sheep or goats epidemiologically linked to confirmed cases of human Q fever.” Currently, coxiellosis is a reportable disease in most states and is also monitored on a national basis.

Prevention on dairies

Q fever infection in humans causes a variety of symptoms ranging from mild fever to serious, life-threatening complications, including abortion. The infection can be worse for individuals who have a weakened immune system, pre-existing valvular heart disease, or are pregnant.

The Centers for Disease Control (CDC) reports 150 to 200 human cases identified each year, with most of these cases occurring in people working at farms, slaughterhouses, and animal research facilities. The diagnosis of Q fever can be challenging for physicians and relies mainly on clinical suspicion and blood tests. Although antibiotics are used to treat Q fever infections, prevention remains the best approach for dairy farmers.

Humans become infected with Q fever by inhaling droplets with the bacteria, by skin contact, or by ingesting contaminated food or water. Coxiella is highly infectious, and exposure to a single organism via inhalation can cause an infection in humans. Certain precautions can reduce the risk of Q fever infection.

One way to greatly reduce exposure to this organism is by avoiding direct contact with animals giving birth, birthing products, and newborn animals. This is especially true for immunocompromised individuals and pregnant women, who should avoid all contact. Unfortunately, this is not possible for all personnel on dairies and other livestock operations.

If calving assistance is necessary or, more importantly, when handling fluids or material associated with an abortion, wearing personal protective equipment such as a well-fitted N95 mask, eye protection with goggles, gloves, and protective outerwear may reduce your risk of Q fever infection. Additionally, promptly disposing of birthing products and cleaning and disinfecting the immediate area where cows or other ruminants have given birth helps prevent the infection from spreading.

Proper handwashing and keeping all open wounds covered with waterproof bandages when working with animals also reduces the risk of Q fever infection though skin contact. Pasteurization kills Coxiella burnetii, and consumption of raw milk or raw milk products should always be avoided.

I spent over a year debilitated by Q fever infection, trying to find answers. Eventually, I connected with a Q fever Facebook group where I found there were many individuals around the world experiencing the same diagnosis as myself. Through my own research and by working with my doctor, I was able to find relief and my symptoms have significantly improved since my diagnosis.

If you or someone you know has developed similar symptoms, including flu-like illness with high fevers and severe headaches, they should contact their doctor. They should tell their doctor their occupation and any activity in the past two to three weeks that may have put them at risk of Q fever infection.

If you are diagnosed with Q fever, USDA and state animal health officials are available to assist producers in mitigating the spread of disease from livestock populations to other farms or people. I’m hoping my story can help someone who might be experiencing similar symptoms and raise awareness in the dairy community. We need to bring awareness to physicians so an early diagnosis can be made and dairy farmers like me don’t suffer from an undiagnosed Q fever infection.