Brucellosis Outbreak in China Not Cause for Concern in the U.S., Experts Say

Brucella bacteria

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Key Takeaways

  • Brucellosis is a bacterial infection transmitted from animals to humans, but not between humans.
  • Experts say a recent outbreak in China isn't cause for alarm in the United States.

There’s currently an outbreak of brucellosis, a disease caused by bacterial infection, in China. People may be wondering what it is and if they are at risk—and if this will play out like COVID-19. But experts says brucellosis spreads very differently than COVID-19.

Experts say there’s not much cause for alarm because of the low rate of human-to-human transmission.

“The outbreak in China should not increase concern in the U.S. The disease does not spread by person-to-person transmission,” Justin Lessler, Phd, an associate professor of epidemiology at Johns Hopkins University, tells Verywell.

Brucellosis is a bacterial infection also known as Malta fever and Mediterranean fever. Brucella abortus, Brucella melitensis and Brucella suis are strains of the bacteria that cause brucellosis, according to the U.S. Centers for Disease Control and Prevention (CDC).

People get brucellosis when they come into contact with livestock carrying brucella, a type of bacteria. People can also get brucellosis from inhaling bacteria, which is what authorities believe happened in China. Human-to-human transmission is extremely rare, but can occur if an infected mother is breastfeeding, the CDC states on its website.

There are about 100 cases a year in the U.S., and this has been the case for decades, Lessler says.

"For the general population in the U.S., the risk is very low," Amira Albert Roess, PhD, MPH, professor of global health and epidemiology at George Mason University, tells Verywell. "Transmission in the U.S. is typically linked to contact with infected wildlife or contaminated food animal products, including unpasteurized milk or raw meat. The dairy and other food animal sectors in the U.S. have the disease under control. Unfortunately, we are seeing more cases in wildlife, particularly in Yellowstone."

What This Mean For You

Brucellosis is quite different from COVID-19 in terms of patient outcomes, and outbreaks can occur anywhere there are livestock.

Brucellosis Symptoms, Diagnosis, and Treatment

Symptoms of brucellosis include fever, headaches, fatigue, and muscle aches. Some symptoms may be long-lasting or permanent, such as neurologic symptoms, organ swelling, depression, and arthritis, the CDC reports.

Doctors use blood and bone marrow tests to detect brucellosis. A blood test, for example, works by detecting antibodies against the bacteria.

Brucellosis is commonly treated with antibiotics. Recovery can take a few weeks to several months, and death only occurs in less than 2% of all cases.

Brucellosis in China

The Health Commission of Lanzhou reported that 3,245 people had tested positive for brucella bacteria as of September 14, 2020.

The outbreak originated at the Zhongmu Lanzhou biological pharmaceutical factory. During late July to late August 2019, the factory was producing brucellosis vaccines for animals. But their production process used expired disinfectants and sanitizers, so the waste gas released still contained the bacteria.

The gas leaked into the air, traveling by wind toward the Lanzhou Veterinary Research Institute, where the outbreak was first recorded. In November of 2019, people began reporting infections. Nearly 200 people were infected by the end of the year, the news agency Xinhua reports. By January 2020, authorities rescinded vaccine production licenses for the pharmaceutical factory.

Bacteria Basics

Eating or drinking raw, unpasteurized dairy products is the most common way people contract bacteria. Cows, goats, sheep, and other animals including dogs can become infected with brucella bacteria. People can’t get the bacteria if they eat cooked meat from an infected animal, the National Park Service reports.

In the U.S., the bacteria is found in bison and elk that reside in the Greater Yellowstone Area.

Infection Perceptions

Jürgen A. Richt, Phd, a professor and director of the Kansas State University Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), tells Verywell that he thinks it’s unfortunate that it took China nine months to inform the public about the bacteria’s release.

Because of the novel coronavirus, people are currently more sensitized to outbreaks of new zoonotic microbes and re-emergence of known zoonotic microbes like brucella, Richt says.

Roess thinks Americans will be concerned about infectious disease outbreaks in other countries for the foreseeable future.

"The important thing to remember about brucellosis is that we've known about it for a very long time and we have effective methods to control it in food animal production," she says.

In other words, it's not a novel disease like COVID-19.

“[Brucellosis] is a systemic bacterial infection as opposed to a respiratory virus [such as SARS-COV-2, the virus that causes COVID-19], so is very different,” Lessler says. “While it shares some of the same symptoms, it is not generally a respiratory illness.”

Lessler is concerned about people focusing so much on outbreaks from China.

“New infectious diseases can emerge anywhere in the world, and there is no guarantee that the next threat will come from China,” he says.

Even in the age of COVID-19, there are other infectious threats, and the safety of the food supply is paramount, he adds.

“We should be concerned with fighting infectious disease no matter where it occurs,” Lessler says.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Negron M, et al. Notes from the Field: Human Brucella abortus RB51 Infections Caused by Consumption of Unpasteurized Domestic Dairy Products — United States, 2017–2019. U.S. Centers for Disease Control and Prevention. 2019.

  2. U.S. Centers for Disease Control and Prevention. Humans and Brucella Species

  3. Health Commission of Lanzhou City. Bulletin of the Handling of the Brucella Positive Antibody Incident of Lanzhou Veterinary Research Institute. Sept. 15, 2020. 

  4. XinhuaNet. Brucella cases caused by contaminated factory exhaust: report. Dec. 27, 2019. 

  5. National Park Service. Brucellosis. Sept. 15, 2017. 

By Kristen Fischer
Kristen Fischer is a journalist who has covered health news for more than a decade. Her work has appeared in outlets like Healthline, Prevention, and HealthDay.