Occupational Infections

Occupational Infections: Introduction - Bugs on the Job

• Infections acquired or worsened due to workplace biological agent exposure.
• Key risk factors:
  • Contact: Infected animals/humans, contaminated materials.
  • Environment: Soil, water, air.
  • Host: Skin breaks, immunosuppression.
• High-risk occupations: Healthcare, agriculture, veterinary, laboratory, sanitation.
• Common transmission: Inhalation, ingestion, skin/mucous membrane contact.
• Prevention pillars: PPE, hygiene, vaccination, engineering controls.

⭐ Many occupational infections are zoonotic (e.g., Anthrax, Brucellosis, Leptospirosis), particularly affecting agricultural and animal handling professions.

Occupational Bacterial Infections - Skin's Tiny Terrors

• Key risk: Contact with animals, animal products, soil, contaminated water.
• Erysipeloid:
  • Erysipelothrix rhusiopathiae; from fish, meat.
  • Violaceous, well-defined, tender plaque (hands/fingers).
  • Tx: Penicillin.
• Cutaneous Anthrax:
  • Bacillus anthracis; from animal hides, wool.
  • Painless papule → vesicle → ulcer → central black eschar; surrounding edema.
  • Tx: Ciprofloxacin, Doxycycline.

  ⭐ The characteristic painless black eschar of cutaneous anthrax is a key diagnostic clue.

• Tuberculosis Cutis:
  • Mycobacterium tuberculosis.
  • Forms: Lupus vulgaris (apple-jelly nodules), Scrofuloderma, TB verrucosa cutis (prosector's wart).
  • Tx: Anti-TB drugs.
• Atypical Mycobacteria (M. marinum):
  • "Fish tank granuloma"; from contaminated water.
  • Papules/nodules (hands), sporotrichoid spread. Culture at 25-33°C.
  • Tx: Clarithromycin.
• Brucellosis:
  • Brucella spp.; from infected animals/dairy.
  • Non-specific skin lesions; systemic symptoms (fever, arthralgia).
  • Tx: Doxycycline + Rifampin.

Occupational Fungal & Viral Infections - Spores & Spots at Work

Fungal Infections:

• Sporotrichosis ("Rose Gardener's Disease"): Sporothrix schenckii.
  • Occ: Gardeners, florists, farmers, miners.
  • Feat: Nodules, ulcers along lymphatics (lymphocutaneous spread).
• Dermatophytoses (Ringworm): Trichophyton, Microsporum spp.
  • Occ: Animal handlers (e.g., T. verrucosum from cattle), farmers, athletes.
  • Feat: Annular, scaly lesions.
• Candidiasis: Candida albicans.
  • Occ: Wet work (dishwashers, bakers), healthcare.
  • Feat: Intertrigo, paronychia.

Viral Infections:

• Orf (Contagious Pustular Dermatitis): Parapoxvirus.
  • Occ: Sheep/goat handlers.
  • Feat: Papulovesicular lesions, targetoid appearance; self-limiting.
• Milker's Nodule: Parapoxvirus.
  • Occ: Cattle handlers.
  • Feat: Firm, painless nodules on hands.
• Herpetic Whitlow: Herpes Simplex Virus (HSV).
  • Occ: Healthcare workers.
  • Feat: Painful vesicles on fingers.
• Molluscum Contagiosum: Poxvirus.
  • Occ: Wrestlers, swimmers.
  • Feat: Pearly, umbilicated papules.

📌 Orf from Ovine (sheep), Milker's from Moo-cows.

⭐ Sporotrichosis classically presents with lymphocutaneous spread - lesions track along lymphatic channels, often described as "sporotrichoid" spread.

Occupational Parasitic Infestations & Prevention - Unwelcome Workplace Guests

• Key Infestations & Risks:
  • Scabies: (S. scabiei) Healthcare/animal workers. Nocturnal pruritus, burrows. Tx: Permethrin 5% cream, oral Ivermectin.
  • Pediculosis: (Lice) Workers with close contact/shared gear. Itching, nits. Tx: Permethrin 1% lotion.
  • Cutaneous Larva Migrans (CLM): (Hookworm larvae) Farmers, gardeners, plumbers. Serpiginous, intensely pruritic tracks. Tx: Albendazole, Ivermectin.
  • Myiasis: (Fly larvae) Outdoor workers. Painful, boil-like lesions with central punctum. Tx: Occlusion, surgical removal.
  • Leishmaniasis (Cutaneous): (Leishmania spp.) Forestry/agricultural workers (endemic areas). Chronic non-healing skin ulcers.
• General Prevention Strategies:
  • Personal Protective Equipment (PPE): Gloves, appropriate footwear, coveralls.
  • Personal Hygiene: Frequent handwashing, regular bathing.
  • Environmental Measures: Pest control, proper sanitation, vector control.
  • Health Education: Awareness of risks, early symptom reporting.
  • Prompt diagnosis & treatment of affected individuals to prevent spread.

⭐ Cutaneous Larva Migrans is frequently acquired by skin contact (e.g., walking barefoot) with soil contaminated by dog or cat feces containing hookworm larvae; common in agricultural workers and gardeners.

High‑Yield Points - ⚡ Biggest Takeaways

• Erysipeloid: E. rhusiopathiae in butchers, fishermen; violaceous, sharply demarcated hand lesions.
• Orf: Parapoxvirus from sheep/goats; targetoid nodule, central umbilication/crusting.
• Milker's Nodule: Parapoxvirus from cattle; similar to Orf, often firmer, less inflamed lesions.
• Cutaneous Anthrax: B. anthracis from animal products; painless papule to black eschar with marked edema.
• Tuberculosis Cutis Verrucosa: M. tuberculosis in pathologists, butchers; warty, hyperkeratotic plaque.
• Herpetic Whitlow: HSV on fingers of healthcare workers; painful grouped vesicles.
• Sporotrichosis: S. schenckii in gardeners; nodules along lymphatics (lymphocutaneous).