A construction worker is diagnosed with mesothelioma. Which of the following is the most likely cause of this disease?

• A. Chronic infection with Streptococcus pneumoniae
• B. Exposure to asbestos fibers
• C. Infection with Mycobacterium tuberculosis
• D. Inhalation of fungal spores such as Histoplasma capsulatum

Answer: (B)

Verified step by step guidance

1. Understand the disease in question: Mesothelioma is a type of cancer that affects the mesothelium, the thin layer of tissue covering many internal organs, most commonly the lining of the lungs (pleura).
2. Identify known causes of mesothelioma: The primary and most well-established cause of mesothelioma is exposure to asbestos fibers, which are microscopic mineral fibers used in construction and other industries.
3. Evaluate the other options: Chronic infection with Streptococcus pneumoniae typically causes pneumonia, not mesothelioma; Mycobacterium tuberculosis causes tuberculosis, a lung infection but not cancer; inhalation of fungal spores like Histoplasma capsulatum causes fungal infections, not mesothelioma.
4. Link the patient's occupation to risk factors: A construction worker is more likely to have been exposed to asbestos fibers during work, which aligns with the known cause of mesothelioma.
5. Conclude that the most likely cause of mesothelioma in this patient is exposure to asbestos fibers, based on the disease pathology and occupational risk.