Which of the following is a recommended control measure for Chlamydia psittaci infection among birds and humans?

• A. Avoid mixing birds from multiple sources
• B. Quarantine new or exposed birds and isolate all ill birds
• C. Test for Chlamydia psittaci before boarding birds or selling them
• D. Screen birds that have frequent public contact (schools, educational facilities)

Answer: (B)

Controlling a zoonotic threat like Chlamydia psittaci relies on preventing introduction and stopping spread within a bird population and to people who handle them. The strongest measure is to quarantine new or exposed birds and to isolate any birds that are ill. Quarantine creates a window to observe health, detect signs of infection, and prevent new birds from mingling with the flock while incubation or shedding could be occurring, which reduces the chance that an infected bird slips in unnoticed. Isolating ill birds directly cuts off a major route of transmission—respiratory secretions and droppings—from spreading to other birds and to humans who handle them. Because many infected birds can shed the organism without obvious illness, this approach addresses both latent and active transmission risks more reliably than relying on testing alone, which can miss infections or yield false negatives. While testing and screening programs are useful parts of a broader control strategy, they don’t replace the protective effect of quarantine and isolation in preventing spread and human exposure.