It took nearly two years for doctors to figure out the cause of his chest pain.
Feral pigs in Florida. Credit: Getty | James Keith
In the fall of 2020, a 77-year-old man in Florida realized he had gotten one of the worst gifts imaginable—one that kept on giving.
According to a case report published in this month's issue of Emerging Infectious Diseases, the man showed up at a Gainesville hospital with chest pain that just wouldn't go away. For nearly two years prior, the man—a pastor living on a rural farm with dogs and goats—had been in and out of hospitals, and on and off of various antibiotics.
Generally, the man wasn't in the best health. His medical history included type 2 diabetes, high blood pressure, high cholesterol, and heart failure with reduced ejection fraction. For the latter, he had an automated implantable cardiac defibrillator (AICD) placed—and it was not his first. The man had a notable history of having gone through multiple defibrillators and revisions, including getting a new generator in 2018. Some possible reasons for such a history could include heavy use of the device and infections.
Throughout his hospital visits in 2019 and 2020, doctors suspected he had an infection lurking in his heart implant. But the germ behind it remained elusive. When they tried to isolate whatever bacteria, fungi, or other pathogen was causing the problem, they couldn't find anything. He was subsequently treated for a "culture-negative" infection. At one point, a test suggested a rare, opportunistic bacterium. But, after treatments with over half a dozen antibiotics for mostly two- to four-week spans over the two years, the discomfort in the left side of his chest would always return.
Hog-wild infection
During the fall 2020 visit, doctors finally rooted out the source of the problem. Blood culture tests showed clumps of some kind of bacteria among his blood cells. Imaging, meanwhile, showed signs of infection around his implant. The doctors were concerned enough that they decided it was time to take the implant out. After removing it, they sent the device and samples to the Florida health department and the Centers for Disease Control and Prevention, which did clinical and genetic testing. They all turned up Brucella suis.
B. suis is an extremely infectious bacteria that's usually found in pigs. The most common symptom in pigs is reproductive losses, such as stillbirths, though they can also develop other symptoms, such as abscesses and arthritis. In humans, it causes an insidious, hard to detect infection called brucellosis, which is used to describe an infection from any Brucella species: B. suis, B. melitensis, B. abortus, and B. canis.
In the US, there are only about 80 to 140 brucellosis cases reported each year, and they're mostly caused by B. melitensis and B. abortus. People tend to get infected by eating raw (unpasteurized) milk and cheeses. B. suis, however, is generally linked to hunting and butchering feral pigs and hogs.
Until recently, the Brucella species were designated as select agents by the US government, a classification to flag pathogens and toxins that have the potential to be a severe threat to public health, such as if they're used in a bioterror attack. The current list includes things like anthrax and Ebola virus. Brucella species were originally listed because they can be easily aerosolized, and only a small number of the bacterial cells are needed to spark an infection. In humans, infections can be both localized and systemic and have a broad range of clinical manifestations. Those include brain infections, neurological conditions, arthritis, anemia, respiratory involvement, pancreatitis, cardiovascular complications, like aneurysms, and inflammation of the spinal cord, among many other things.
In January, federal officials removed Brucella species from the select agents list—a designation that limits the types and amount of research that can be done on a pathogen. According to the US Department of Agriculture, the reason for the removal was to ease those limits, thereby making it easier for researchers to conduct veterinary studies and develop vaccines for animals.
Perilous present
After finding B. suis, the doctors went to gather more information about how the man could have contracted this rare species. The man said he wasn't a hunter, but recalled receiving a gift of feral swine meat on several occasions in 2017 from a local hunter. Though he couldn’t recall the specific hunter who gave him the biohazardous bounty, he did remember handling the raw meat and blood with his bare hands—a clear transmission risk—before cooking and eating it.
"This encounter likely served as his exposure to B. suis," his doctors concluded. They noted that it is possible the dog and goats on the farm where the man lived also could have picked up the infection from pigs and passed it on to him. But, the doctors deemed this less likely given that there was no evidence of sick animals on the farm, and the man said he didn't interact with them anyway.
Still, the risk from the gifted meat wasn't over yet. Because B. suis is so infectious, upon identifying the source of the man's infection, the doctors went back and notified the man's previous health care providers and the clinical laboratories that tested his samples to make sure no one was exposed to the infection. Through subsequent interviews, at least three laboratory workers were found to have had high-risk exposures. To make sure they didn't become infected, they underwent clinical and serologic monitoring for six months and received post-exposure prophylaxis, the doctors reported.
The man, meanwhile, finally received the proper course of antibiotics recommended by the CDC for brucellosis treatment, which was a combination of oral doxycycline and rifampin for six weeks. At the end of the course, his blood cultures were negative. A few months later, he had a new AICD placed. A year after the ordeal, lingering signs of the infection had faded. At a routine check-up after more than 3 years, he appeared to remain free of brucellosis.
The doctors say the case should raise awareness of the potential for brucellosis in Florida, particularly in patients with implanted cardiac devices. They note that there are more than a million feral swine in the state and any hunters are at risk. Moreover, they highlighted a small study from Saudi Arabia, where Brucella is endemic, that found that the bacteria were behind 11 percent of cardiac device infections.
After the long journey for this patient to receive a proper diagnosis, clinicians in Florida should keep brucellosis in mind—and residents should think twice about any gamey gifts.