Histoplasmosis

Related Infectious Disease Risks for Workers

What to know

In addition to Histoplasma, there are other concerns for workers who may contact birds, bats, or their droppings. These include Cryptococcus neoformans, Rabies virus, and Chlamydia psittaci.

landscape work occurring in the woods, where soil might contain histoplasma

Cryptococcosis

Cryptococcus neoformans is a causative agent of the fungal infection cryptococcosis, also known as C. neoformans infection. C. neoformans lives throughout the world in soil, decaying wood, tree hollows, or bird droppings.12

People can become infected with C. neoformans after breathing in the microscopic fungus. However, most people exposed to the fungus never get sick from it.

Occupational considerations

Avoiding C. neoformans is generally difficult because it is common in the environment. Outdoor occupations, like landscaping and outdoor construction, have been associated with increased risk of cryptococcosis.3 Little is known about the specific activities that may increase risk of C. neoformans infection. However, working near bird droppings may increase exposure.

Healthcare providers should be aware of the increased risk of cryptococcosis in outdoor workers. They should consider these diseases in any patients with unexplained:

  • Lung disease
  • Lung nodules
  • Meningitis

Find more information on C. neoformans infection including symptoms, diagnosis, and treatment here.

Rabies

Rabies is a fatal but preventable viral disease.4 It can spread to people and pets if they are bitten or scratched by a rabid animal. In the United States, rabies is mostly found in wild animals like bats, raccoons, skunks, and foxes.

Occupational considerations

Workers are at risk of rabies if they5:

  • Receive a bite from a rabies-infected animal or human
  • Have an open wound, scratch, or abrasion that makes contact with rabies-infected saliva or other rabies-infected tissue (neural tissue)
  • Work in a laboratory where rabies virus is aerosolized or where workers may be exposed via needlesticks or other accidents
  • Frequently enter into caves where bats are present

Workers who encounter a dead bat should never pick up the bat with bare hands. In bats that died from rabies, the virus can remain in the carcass until decomposition is well-advanced and dry. Instead, whenever possible, use a shovel or other tool to pick up and move the dead bat. If the bat must be handled, wear heavy gloves. This should minimize risk of an accidental scratch or contamination of existing abrasions on the worker's hands.

Rabies can also be prevented by vaccinating people at high risk of infection before exposure occurs. These groups include5:

  • Rabies research laboratory workers
  • Veterinarians or those who regularly enter caves with bats and bat droppings
  • Animal control workers working with animals that live on the ground

If you are exposed

If you do come into contact with a rabid animal or have a high-risk exposure, it is important to seek treatment as soon as possible. The efficacy of post-exposure prophylaxis approaches 100% when prompt medical care is provided.4 Talk to a healthcare provider about whether you need post-exposure prophylaxis, if:6

  • You are get a bite or scratch
  • You are unsure if a rabies virus exposure occurred

Find more information on rabies including symptoms, diagnosis, and treatment here.

Psittacosis

Psittacosis is an infectious disease caused by the bacteria Chlamydia psittaci.7 C. psittaci can infect humans who breathe in aerosolized dried droppings or respiratory secretions of infected birds. Birds include psittacines (cockatiels, parakeets, parrots, and macaws), pigeons, or poultry.89 Transmission can also occur through:

  • Direct contact with feathers
  • Direct contact with tissues
  • Direct contact with respiratory secretions of infected birds
  • Mouth-to-beak contact.8

Occupational considerations

Workers in occupations that involve contact with live birds or bird carcasses are at increased risk of infection. Such occupations include:789101112

  • Veterinarians
  • Bird breeders
  • Poultry workers
  • Pet shop workers

Outbreaks have been described in turkey processing plants and chicken slaughter plants.12131415 An outbreak among English office workers was likely caused by indirect environmental exposure to infected pigeons.16

Resource ‎

The National Association of State Public Health Veterinarians provides recommendations to prevent transmission to humans.
Compendium of Measures to Control Chlamydia psittaci Infection Among Humans (Psittacosis) and Pet Birds (Avian Chlamydiosis)

The recommendations to prevent occupational exposures to C. psittaci include:

  • Quarantine of newly-acquired birds or birds exposed to ill birds
  • Cleaning and disinfecting cages
  • Other animal husbandry practices

Those handling ill birds or cleaning their cages should use appropriate personal protective equipment:

  • Protective clothing
  • Gloves
  • Eye protection
  • Disposable NIOSH-approved filtering facepiece respirator8

Find more information on psittacosis including symptoms, diagnosis, and treatment here.

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Content Source:
National Institute for Occupational Safety and Health
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