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EQUINE HEALTH
PSITTACOSIS
in Horses
by Heather Smith Thomas
Psittacosis is a rare but potentially fatal called parrot fever or parrot disease and is most Centers for Disease Control and Prevention
zoonosis - an animal disease that can
be transmitted to humans, caused by Chlamydia psittaci, a bacterium that is typically associated with birds. C. psittaci is capable of infecting mammals, however, such as horses, sheep, cattle, and goats. It has often been
commonly spread by parrots, parakeets and other birds of the parrot (psittacine) family. It can cause respiratory disease and skin infections in humans.
IN HUMANS
Psittacosis was first described as a human disease in Europe in 1879, when the first outbreak of psittacosis linked the disease to pet parrots and finches. It was rarely reported in the United States until a pandemic occurred in 1929-1930. Despite these outbreaks, psittacosis is regarded as a rare zoonotic infection.
Thus, there is a decreased awareness of this disease among the public as well as health care professionals, and when coupled with the need for specialized testing, under-diagnosis of psittacosis is likely when examining reports of psittacosis’ prevalence and incidence. The
(CDC) classifies psittacosis as a reportable condition in most states with estimated confirmed cases numbering fewer than 10 annually. Most experts attribute this to under- diagnosis and underreporting.
Therefore, this disease is thought to be uncommon in the U.S. although it is present, primarily in birds. In a 1982 survey, C. psittaci was isolated from 20 to 50% of necropsied pet birds in California and Florida.
Psittacosis in people is most commonly associated with pet birds, like parrots and cockatiels, and with poultry, like turkeys and ducks. These bacteria can infect people exposed to infected birds, but infected birds do not always show signs of the disease or seem sick. Both sick birds and infected birds without signs of illness shed the bacteria in their droppings and respiratory secretions. When these
92 SPEEDHORSE November 2022
“Psittacosis is a rare but potentially fatal zoonosis – an animal disease that can be transmitted to humans, caused by Chlamydia psittaci, a bacterium that is typically associated with birds.”