Polly can make you sick: Pet bird-associated diseases

Campylobacteriosis

The main reservoirs for Campylobacter jejuni are wild birds and poultry, although this bacterium can also affect other animals and pet birds.² The most commonly affected pet birds are psittaciforms (parrots) and passeriforms (finches and canaries).

The organism colonizes the small intestine and colon of birds and can be spread to humans through contact with feces or carcasses of infected animals.^33–35 Birds with campylobacteriosis develop hepatitis, lethargy, loss of appetite, weight loss, and yellow diarrhea and often die of the illness (R. Stevenson, personal communication, 2007).

The most important mode of transmission to humans is through handling or consuming chicken, milk, or other products contaminated with feces of carrier animals. However, in up to 24% of cases, the source of infection is unknown.^33,34

Human infection with C jejuni most commonly leads to an acute, self-limited gastrointestinal illness characterized by fever, diarrhea, and abdominal cramps. The diarrhea is typically watery or bloody and occurs 8 to 10 times a day at peak illness. Fever can persist for up to a week. Most cases resolve within 7 days, but some patients may have a relapsing diarrheal illness lasting several weeks. Between 20% and 40% of cases of Guillain-Barré syndrome are preceded by infection with C jejuni.³⁵

Giardiasis

Giardiasis is an intestinal protozoal infection caused by Giardia species (primarily G lamblia) that affect humans and other mammals. The parasite is found in bird droppings, but the role of birds in transmission to humans is unclear. Most infections are transmitted via contaminated surface water supplies, although person-to-person transmission has been documented.³⁶ Infected pet birds have signs of gastroenteritis and can be treated, but reinfection often occurs.³⁷

Giardia infections in humans are often asymptomatic, but about 50% of patients have diarrhea, abdominal pain, bloating, belching, nausea, and vomiting 3 days to 3 weeks after ingesting the parasite. A clinical clue may be new-onset lactose intolerance. Symptoms usually resolve after a week. Prolonged infection occurs in up to 20% of patients. People with hypochlorhydria or hypogammaglobulinemia, children, and travelers to endemic areas are at higher risk of infection.³⁷

DISEASES PRESENTING WITH SKIN SYMPTOMS

Pasteurellosis

Pasteurellosis is caused by Pasteurella multocida, an inhabitant of the healthy nasopharynx of some birds and also the causative agent of avian cholera.³⁸ Many pet birds that acquire systemic Pasteurella infection from a cat bite die of avian cholera (Stevenson R, personal communication, 2007).

Pasteurella organisms are transmissible to humans via bites or scratches from pet birds. Infected wounds in humans are usually red and painful, but the physical findings may lead one to underestimate the severity of infection. Transmission via respiratory droplets is rare but may cause acute or subacute bronchitis, pneumonia, or septicemia.³⁸

Erysipeloid

Erysipeloid, caused by the bacterium Erysipelothrix rhusiopathiae, is transmissible to humans via contact with domestic or wild fowl. Infection in pet birds can cause sepsis but is rarely seen in veterinary practice (R. Stevenson, personal communication, 2007).^38,39

Human infection typically affects broken skin, causing a dramatic, localized skin infection that is painful and pruritic; at first it is livid-red, then blue-red. The infection can spread to nearby joints. Septicemia and endocarditis in humans are rare complications.⁴⁰

Cryptococcosis

Cryptococcosis, caused by the encapsulated yeast Cryptococcus neoformans, can be harbored and transmitted by asymptomatic pet birds such as cockatoos via colonization of the gastrointestinal tract.^38,41 The organism is found in soil contaminated by feces of colonized birds.

Pulmonary symptoms and meningitis are more typical of cryptococcal disease in general, although when contracted from a pet bird via a break in the skin, cutaneous cryptococcosis usually presents with skin lesions resembling cellulitis, molluscum, herpes, and Kaposi sarcomalike papulonodules.⁴² Infection beyond the skin in immunocompromised patients may involve the lungs and the central nervous system.⁴¹ Prostate and eye infections have also been reported.³⁸

Avian mite dermatitis

Birds carry several kinds of mites: feather or “red” mites (which do not affect humans) and mites that can affect humans such as Ornithonyssus sylviarum (the northern fowl mite) and Dermanyssus gallinae (the poultry mite or chicken mite) (R. Stevenson, personal communication, 2007). O sylviarum and D gallinae are found in the commercial poultry industry, but uncommonly, pet birds can harbor them (R. Stevenson, personal communication, 2007).^42–44

In humans, mites can cause an intensely pruritic, papular-papulovesicular eruption.⁴²

Nontuberculous mycobacteriosis

Nontuberculous mycobacteria (Mycobacterium species chelonae, abscessus, fortuitum, avium, kansasii, ulcerans, and marinum) are ubiquitous in the environment and can colonize animals. M avium subsp avium causes avian tuberculosis.³⁸ Birds may carry mycobacterial organisms on beaks, claws, and talons, facilitating passage to humans (J.M. Gaskin, personal communication, 2006). In one reported case, M chelonae skin infection was probably transmitted in this manner to a bird-keeper via a bird bite.⁴⁵

In symptomatic nontuberculous mycobacterial infections, the site of inoculation usually determines the presenting signs. Mycobacteriosis should be suspected when skin or lung infections fail to improve with empiric treatment. Patients with structurally abnormal lungs or immunosuppression may be at higher risk of pulmonary or disseminated disease from infected birds.^46,47

Acknowledgment: The authors extend special thanks to Jack M. Gaskin, DVM, PhD, Department of Infectious Disease and Pathology, University of Florida, Gainesville, FL; Rhoda Stevenson, DVM, Exotic Bird Hospital, Jacksonville, FL; and Stephanie L. Hines, MD, Section of General Internal Medicine, Mayo Clinic, Jacksonville, FL, for their review of this paper. Editing, proofreading, and reference verification were provided by the Mayo Clinic Section of Scientific Publications.