HEP 444 Case Report The Red Mist

Name

ASU

HEP 444: Epidemiology

19th August 2022

Case Report-The Red Mist

1) Describe the setting for the story in terms of persons affected, place of the disease outbreak, and time from the initial ill person (index case) to the end of the outbreak

The red mist story happened at the Austin Medical Centre in Austin, Minnesota, in September 2007. A Hispanic immigrant suffered from a peculiar disease and developed symptoms such as tingling, pain, and difficulty walking. The Hispanic immigrant worked at a local meat processing plant called Quality Pork Processors (QPP). The doctors communicated with the immigrant with the help of a translator who appeared perplexed by the turn of events because she had previously interviewed other patients with similar symptoms. Upon perusing medical files at the facility, medical staff discovered that there had been ten previous cases of patients demonstrating similar symptoms dating back to December 2006. After consulting with the Minnesota Department of Health, the experts discovered that muscle pain and weakness were common among slaughterhouse workers due to the nature of the work, which often involved standing on their feet the entire day and performing repetitive tasks.

2) Describe the processes of elimination that the epidemiologists used in identifying the disease causes of the employee’s symptoms.

Two weeks after the first case was reported, the chief occupational nurse at QPP called the state health department and spoke with Richard Danila. She had referred three patients complaining of tingling, pain, and heavy legs to the Mayo clinic for special testing and was worried that a new epidemic could spread at the plant. Aaron Devries, a medical detective, was assigned to this case. Devries visited Mayo clinic, the Austin Medical Center, and the meat processing plant, all in one day to solve the puzzle, and discovered that the patients were suffering from polyneuropathy, a neurologic disorder that caused damage to several peripheral nerves. The detective also discovered that symptoms of the epidemic included muscle weakness, head and neck pain, numbness, and burning pain in the hands and feet. Some patients had lost sensation in their lower bodies and required the help of walkers and wheelchairs.

Epidemiologists focused on polyneuropathies and understood that the condition could have different causes, such as diabetes or physical traumas. Other probable causes were chemical poisoning or contagious infections which spread from animals to humans. The pathogen passed from hogs to humans is trichinella, but this one often causes diarrhea and stomach cramps. Moreover, the pathogen is seldom found in farm-bred pigs, and it was ruled out on these grounds. Devries also considered a degenerative brain disease caused by a prion but ruled this out because the outbreak affected peripheral nerves and not brain tissue and the fact that prion diseases are degenerative and incurable. Devries was convinced that a food-related issue or repetitive stress did not cause the disease. He was also convinced that the illness was not transmitted from one person to another because none of the patient’s family members had suffered similar symptoms.

Devries then moved to the QPP factory and took a tour of the facility with the CEO, the human resources manager, and the head nurse and discovered that most of the patients exhibiting the common symptoms of the outbreak worked in a warm room (where the carcasses are butchered). Having narrowed it down to the warm room, Devries sought help from James Sejvar, a neurology expert, and Peter Dyck and James Dyck, experts in peripheral neuropathies. Devries also sought the intervention of Daniel Lachance, a neurologic disorders research scientist. The experts suggested that the index patient displayed relapsing symptoms, suggesting an autoimmune condition such as chronic inflammatory demyelinating polyneuropathy (CIDP). CIDP involves the destruction of the myelin sheath. CIDP can often be caused by an infection and Campylobacter bacteria. This further informed the scientists of the possibility that the swine were the cause of the bacterial infection.

Armed with this information and other experts, the scientists entered the cavernous warm room. In this room, one of the scientists, Ruth Lynfield, noticed a strange reddish mist blowing around the warm room, intensified by the presence of an overhead fan with pink particles settling on the people at the head table. Notably, most of the workers had safety gear that could not prevent them from breathing in the red mist. Ruth and another scientist, Wading, recommended that using air blasting machinery to harvest brains be stopped. They called for dismantling this machinery and agreed to provide the head table workers with additional protective equipment. This intervention ended polyneuropathy in Austin, Minnesota.

3. What were the two studies that the epidemiologists used, first to identify who was at risk for having the symptoms, and second to identify the cause of the autoimmune response?

The epidemiologists developed a questionnaire to assist the investigators in identifying disease risk factors by comparing the experiences of the QPP patients and the workers who had remained healthy. Thirteen patients enrolled in the study, two groups of health workers who served as controls, forty-nine who worked at the head table, and fifty-six who worked anywhere in the room. All the thirteen neuropathy patients had worked in the warm room, and seven had worked at the head table. Eight of the patients were women, and 80% were Hispanic. The patients and healthy controls were interviewed on their health histories, jobs and work histories, and the potential causes of exposure outside the factory. The factory’s medical station took a throat swab and blood sample. Controls for the distance from the head table were tabulated. The study’s results indicated that the thirteen neuropathy patients were 6.9 times more likely to have worked at the head table than the warm room controls and 7.5 times more likely to have blown brains or backed heads than the headroom controls.

The second study attempted to investigate the cause of the autoimmune response. Server and colleagues surveyed factories in the US that used compressed air devices to process hog brains. They studied 26 federal inspected swine abattoirs and found six processed swine brains, of which three used pressurized air. The researcher also notified the World Health Organization, the World Organization for Animal Health, and the European Center for Disease Prevention and Control to get information on overseas data. However, these organizations did not find any organization overseas that relied on compressed air to harvest hog brains. The pork processing plants in Indiana and Nebraska were home-made, similar to the one in Minnesota, and were designed in such a way as to allow for pressurized air. Results indicated five positive cases in Indiana and one positive case of peripheral neuropathy in Nebraska. Later, a study in Indiana identified four more cases of polyneuropathy, bringing the total to nine. It was therefore identified that there was a positive correlation between pressurized air that caused the red mist and the polyneuropathy cases. An autoimmune response was also suggested when patients started improving when they were no longer exposed to the brain mist or when steroids and other immunotherapies were administered.

4. Describe the epidemiologist’s conclusion that led to the outbreak.

Neurologists concluded that the outbreak was caused by the disruption of nerve impulses which involve membrane channels that allow the passage of calcium, potassium, and sodium ions. Channelopathies are caused by inborn mutations or an autoimmune reaction caused by a foreign body. The Austin outbreak was caused by an antibody attack on the potassium channels, leading to weakness, pain, and sometimes lower limb paralysis.

5. Discuss ethical concerns of this employment setting and regard for worker safety.

One of the ethical concerns was the failure of the employer to provide the safety gear for employees to work in the warm room. This exposed employees to the red mist emanating from the hogs' brains and were made worse by an electrical fan in the room. The employer failed to protect his employees from the exposure and was therefore liable to compensate the employees under the law. The employer should have acted ethically by providing safety gear for the task they were involved in.

Another ethical concern was the failure of the employer to compensate employees who suffered from the outbreak while in employment. The employer later fired workers who filed for compensation because they were working under forged or stolen identities. The employer should have compensated the employees and allowed the index employee to continue working even after the compensation had been settled.

References

Levitt. (2015). Deadly Outbreaks: How medical detectives save lives threatened by killer pandemics, exotic viruses, and drug-resistant parasites. Skyhorse Publishing.