Welder's Anthrax Case and Novel Treatment
Louisiana has documented the ninth known case of welder's anthrax in the United States, which also represents the first clinical application of the monoclonal antibody medication obiltoxaximab for this condition. The case details were published in a recent Morbidity and Mortality Weekly Report by the US Centers for Disease Control and Prevention (CDC).
Understanding Welder's Anthrax
Welder's anthrax is a form of pneumonia caused by anthrax toxin–producing Bacillus cereus bacteria, a pathogen related to Bacillus anthracis. Historically, six of the preceding eight documented cases in the US have resulted in fatalities. Identified risk factors include exposure to dust and welding fumes, inadequate ventilation, and insufficient use of personal protective equipment (PPE).
Patient Presentation and Treatment
In September 2024, an 18-year-old welding apprentice in Louisiana, with no history of vaping, smoking, or excessive alcohol use, developed severe pneumonia and respiratory failure requiring intubation and mechanical ventilation. The patient had been employed as a welder for six months prior to the onset of illness.
Confirmation of anthrax toxin genes was made by the Louisiana Department of Health and the CDC in the patient’s blood and in samples collected from the worksite.
Treatment administered included standard multidrug antimicrobial therapy, drainage of a pleural effusion, and obiltoxaximab. The obiltoxaximab was acquired from the US Strategic National Stockpile and was given approximately 34 hours after welder’s anthrax was suspected, which was about one week following symptom onset.
Outcome and Recommendations
The patient exhibited rapid improvement within days, leading to the discontinuation of mechanical ventilation. Discharge occurred after 26 days, and symptoms had fully resolved by a three-month follow-up examination. This case suggests potential benefits of combining antitoxin therapy with standard antimicrobial treatments for welder’s anthrax.
To mitigate infection risks, employers in welding and metalworking industries are advised to adhere to best practices for minimizing workplace exposure to welding fumes and gases, as well as to soil and dust in areas where the bacteria may be present. Further research and analysis of environmental, occupational, and host factors are necessary to establish effective prevention and control measures.