Chlamydia psittacosis is a bird pathogen, which can be transmitted to humans from birds, poultry, cats, dogs, horses, and mice. Birds are infected worldwide, particularly pigeons, raptors, and caged birds. Human psittacosis can begin as an acute respiratory infection, after inhaling bird droppings, from the environment or contaminated ventilation systems; can cause life-threatening respiratory infections or mild symptoms; and in some patients can cause acute transverse myelitis. Before antibiotics, psittacosis caused many fatal epidemics linked to pet birds; and the CDC considers ownership of pet birds a public health concern.

In a 2018 case report, a patient with a month-long history of respiratory infection and other systemic symptoms was being treated with moxifloxin, without improvement.  Her psittacosis serology was negative; however, a PCR nasal swab with genome-specific real-time proved she had psittacosis, and her psittacosis genome matched the psittacosis genome found in her pet parrot. PCR testing for chlamydia provided the correct diagnosis and treatment.

Medical practitioners are seldom trained to diagnose psittacosis; serologic testing can be unreliable; and PCR testing is discouraged due to lack of understanding of the need, and lack of insurance reimbursement. Psittacosis causes autoimmune diseases, cancer, and chronic eye diseases. Psittacosis injected IV into rabbits caused acute eye infections. Birds develop melanoma of the eye; and psittacosis is the probable cause of ocular melanoma clusters, along pigeon and raptor migration routes.

Psittacosis is not a rare disease—it is a rarely diagnosed disease!  Psittacosis is widespread in birds and animals, is transmissible to humans, and chronic diseases caused by psittacosis are prevalent. Psittacosis is a dangerous pathogen, which is under-diagnosed and under-reported, in acute and chronic disease.

Weygaerde, Y, et al.  “An unusual presentation of a case of human psittacosis”. www.sciencedirect.com/science/article/pii/S221300711730401X