Other Infectious Disease Risks for Workers who Disturb Bat or Bird Droppings

In addition to Histoplasma, Cryptococcus neoformans may also be a health risk for workers who disturb accumulations of bird or bat droppings. Other concerns include rabies virus for workers who handle dead bats and Chlamydia psittaci for workers who work in environments of certain birds.

Cryptococcus neoformans is a causative agent of the fungal infection cryptococcosis. C. neoformans lives in the environment throughout the world. Its specific habitats include soil, decaying wood, tree hollows, or bird droppings.1,2 People can become infected with C. neoformans after breathing in the microscopic fungus, although most people exposed to the fungus never get sick from it. Cryptococcosis often presents as meningitis or meningoencephalitis, with symptoms including headache, fever, neck pain, and sensitivity to light.3,4 Infection may also develop in the lungs, causing cough, chest pain, or shortness of breath.5

C. neoformans infections are rare in otherwise healthy people. Most cases occur in people who have weakened immune systems, particularly those who have advanced HIV/AIDS.6–8 Find more information on C. neoformans infection, including diagnosis and treatment, on the CDC C. neoformans Infections website.

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.9 Little is known about the specific activities that may increase risk of C. neoformans infection, although working near bird droppings may increase exposure. Healthcare providers should be aware of the increased risk of cryptococcosis in outdoor workers and consider this disease in patients with unexplained lung disease, lung nodules, or meningitis, even in patients without known weakened immune systems.


  1. Brown GD, Denning DW, Gow NW, Levitz SM, Netea MG, White TC [2012]. Hidden killers: human fungal infections. Sci Transl Med 4(165): 165rv113.
  2. Lazera MS, Salmito Cavalcanti MA, Londero AT, Trilles L, Nishikawa MM, Wanke B [2000]. Possible primary ecological niche of Cryptococcus neoformans. Med Mycol 38(5):379–383.
  3. Bratton EW, El Husseini N, Chastain CA, Lee MS, Poole C, Stürmer T, Juliano JJ, Weber DJ, Perfect JR [2012]. Comparison and temporal trends of three groups with cryptococcosis: HIV-infected, solid organ transplant, and HIV-negative/non-transplant. PLoS One 7(8):e43582.
  4. Sabiiti W, May RC [2012]. Mechanisms of infection by the human fungal pathogen Cryptococcus neoformans. Future Microbiol 7(11): 1297–1313.
  5. Chang WC, Tzao C, Hsu HH, Lee SC, Huang KL, Tung HJ, Chen CY [2006]. Pulmonary cryptococcosis: comparison of clinical and radiographic characteristics in immunocompetent and immunocompromised patients. Chest 129(2): 333–340.
  6. George IA, Spec A, Powderly WG, Santos CAQ [2018]. Comparative epidemiology and outcomes of Human Immunodeficiency virus (HIV), Non-HIV non-transplant, and solid organ transplant associated cryptococcosis: a population-based study. Clin Infect Dis 66(4): 608–611.
  7. Pappas PG [2013]. Cryptococcal infections in non-HIV-infected patients. Trans Am Clin Climatol Assoc 124:61–79.
  8. Shaheen AA, Somayaji R, Myers R, Mody CH [2018]. Epidemiology and trends of cryptococcosis in the United States from 2000 to 2007: A population-based study. Int J STD AIDS 29(5):453–460.
  9. Hajjeh RA, Conn LA, Stephens DS, Baughman W, Hamill R, Graviss E, Pappas PG, Thomas C, Reingold A, Rothrock G, Hutwagner LC, Schuchat A, Brandt ME, Pinner RW [1999]. Cryptococcosis: population-based multistate active surveillance and risk factors in human immunodeficiency virus-infected persons. Cryptococcal Active Surveillance Group. J Infect Dis 179(2):449–454.

Rabies is a fatal but preventable viral disease.1 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. However, in many other countries dogs still carry rabies, and most rabies deaths in people around the world are caused by dog bites.

The rabies virus infects the central nervous system and can lead to death.1 There is often discomfort or a prickling or itching sensation at the site of the bite prior to fever and vague symptoms before progressing within days to acute symptoms of cerebral dysfunction, anxiety, confusion, and agitation. As the disease progresses, the person can experience delirium, abnormal behavior, hallucinations, hydrophobia (fear of water), and insomnia. Find more information about rabies on the CDC Rabies website.

Occupational considerations

Workers who have the following exposures are at risk of rabies2:

  • Bite from a rabies-infected animal or human
  • Contamination of an open wound, scratch, or abrasion 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
  • Frequent entry into caves where bats are present

Workers who encounter a dead bat should never pick up the bat with bare hands. In the unlikely event the bat died from rabies, the rabies 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, heavy gloves should be worn to 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 include2:

  • Workers at continuous or frequent risk of exposure to rabies virus (rabies research laboratory workers)
  • Workers or other people who have exposures to rabies virus that might be recognized or unrecognized (veterinarians, those who regularly enter caves where bats and bat droppings are present)
  • Workers or other people who have infrequent exposure to recognized sources of rabies (animal control workers working with animals that primarily live on the ground (terrestrial animals) where rabies is uncommon to rare)

If you do come into contact with a rabid animal or have a high-risk exposure, the efficacy of post-exposure prophylaxis approaches 100% when prompt medical care is provided. 1 If you are bitten, scratched, or unsure whether a rabies virus exposure occurred, talk to a healthcare provider about whether you need post-exposure prophylaxis.3


  1. Centers for Disease Control and Prevention (CDC) [2020]. Rabies. https://www.cdc.gov/rabies/index.html. [Accessed November 16, 2020].
  2. Manning SE, Rupprecht CE, Fishbein D, Hanlon CA, Lumlertdacha B, Guerra M, Meltzer MI, Dhankhar P, Vaidya SA, Jenkins SR, Sun B, Hull HF; Advisory Committee on Immunization Practices CDC [2008]. Human rabies prevention—United States, 2008: recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 57 (RR-3):1–28.
  3. Rupprecht CE, Briggs D, Brown CM, Franka R, Katz SL, Kerr HD, Lett SM, Levis R, Meltzer MI, Schaffner W, Cieslak PR; CDC [2010]. Use of a reduced (4-dose) vaccine schedule for postexposure prophylaxis to prevent human rabies: recommendations of the advisory committee on immunization practices. MMWR Recomm Rep 59(RR-2):1–9.

Psittacosis is an infectious disease caused by the bacteria Chlamydia psittaci. The disease is most commonly associated with pneumonia caused by certain bacteria (atypical pneumonia), but the severity of illness can range from mild illness to serious, impacting multiple organ systems.1 Patients may develop mild illness with abrupt onset of fever, chills, headache, and muscle aches after an incubation period of 5–14 days.2 Dry cough is often present. Find more information on signs, symptoms, diagnosis, and treatment of psittacosis on the CDC Psittacosis website.

C. psittaci is transmitted to humans through inhalation of aerosolized dried droppings or respiratory secretions of infected birds such as psittacines (cockatiels, parakeets, parrots, and macaws), pigeons, or poultry.2,3 Transmission can also occur through direct contact with feathers, tissues, respiratory secretions of infected birds, or by mouth-to-beak contact.2

Occupational considerations

Workers in occupations that involve contact with live birds or bird carcasses are at increased risk of infection. Such occupations include:1–6

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

Outbreaks have been described in turkey processing plants and chicken slaughter plants.6–9 An outbreak among English office workers was likely caused by indirect environmental exposure to infected pigeons.10

The National Association of State Public Health Veterinarians published the Compendium of Measures to Control Chlamydia psittaci Infection Among Humans (Psittacosis) and Pet Birds (Avian Chlamydiosis), 2017, which provides recommendations to prevent transmission to humans.2 The recommendations to prevent occupational exposures to C. psittaci include quarantine procedures of newly-acquired birds or birds exposed to ill birds, cleaning and disinfecting cages, and other animal husbandry practices. Those handling ill birds or cleaning their cages should use appropriate personal protective equipment, including protective clothing, gloves, eye protection, and a disposable NIOSH-approved filtering facepiece respirator.2


  1.  Basarab M, Macrae MB, Curtis CM [2014]. Atypical pneumonia. Curr Opin Pulm Med 20:247–251.
  2. Balsamo G, Maxted AM, Midla JW, Murphy JM, Wohrle R, Edling TM, Fish PH, Flammer K, Hyde D, Kutty PK, Kobayashi M, Helm B, Oiulfstad B, Ritchie BW, Stobierski MG, Ehnert K, Tully TN Jr [2017]. Compendium of measures to control Chlamydia psittaci infection among humans (psittacosis) and pet birds (avian Chlamydiosis), 2017. J Avian Med Surg 31:262–282.
  3. Centers for Disease Control and Prevention [1990]. Psittacosis at a turkey processing plant–North Carolina, 1989. MMWR Morb Mortal Wkly Rep 39:460–461.
  4. Maegawa N, Emoto T, Mori H, Yamaguchi D, Fujinaga T, Tezuka N, Sakai N, Ohtsuka N, Fukuse T [2001]. Two cases of Chlamydia psittaci infection occurring in employees of the same pet shop. Nihon Kokyuki Gakkai Zasshi 39:753–757.
  5. Heddema ER, van Hannen EJ, Duim B, de Jongh BM, Kaan JA, van Kessel R, Lumeij JT, Visser CE, Vandenbroucke-Grauls CMJE [2006]. An outbreak of psittacosis due to Chlamydophila psittaci genotype A in a veterinary teaching hospital. J Med Micribiol 55:1571–1575.
  6. Vanrompay D, Harkinezhad T, van de Walle M, Beeckman D, van Droogenbroeck C, Verminnen K, Leten R, Martel A, Cauwerts K [2007]. Chlamydophila psittaci transmission from pet birds to humans. Emerg Infect Dis 13:1108–1110.
  7. Vorimore F, Thébault A, Poisson S, Cléva D, Robineau J, de Barbeyrac B, Durand B, Laroucau K [2015]. Chlamydia psittaci in ducks: a hidden health risk for poultry workers. Pathog Dis 73:1–9.
  8. Shaw KA, Szablewski CM, Kellner S, Kornegay L, Bair P, Brennan S, Kunkes A, Davis M, McGovern OL, Winchell J, Kobayashi M, Burton N, de Perio MA, Gabel J, Drenzek C, Murphy J, Holsinger C, Forlano L. Psittacosis outbreak among workers at chicken slaughter plants, Virginia and Georgia, USA, 2018. Emerg Infect Dis 25(11):2143–2145.
  9. Hadler SC, Castro KG, Dowdle W, Hicks L, Noble G, Ridzon R [2011]. Epidemic Intelligence Service investigations of respiratory illness, 1946-2005. Am J Epidemiol 174:S36–46.
  10. Mair-Jenkins J, Lamming T, Dziadosz A, Flecknoe D, Stubington T, Mentasti M, Muir P, Monk P. A Psittacosis Outbreak among English Office Workers with Little or No Contact with Birds, August 2015. PLoS Curr. 2018 Apr 27.