Chlamydophilosis is a bacterial infection that can range from subclinical through to acute or chronic disease states. It is characterised by respiratory, digestive or systemic infection and can affect a wide variety of bird species, including turkeys, pigeons, ducks, psittacines (such as parrots), although chickens are not commonly affected. Chlamydophilosis can affect other animal species and is a zoonotic disease (can be transmitted to humans). Symptoms in birds include fever, discharges from the nostrils and eyes, green to yellow-green droppings, conjunctivitis, sinusitis, inactivity, ruffled feathers, weakness, loss of appetite and weight loss. The disease in humans is usually respiratory and characterised by rapid onset of flu-like symptoms. Pneumonia, organ failure, and death can result if the disease is severe or left untreated.
Chlamydophilosis is caused by the bacterium Chlamydophila psittaci. This bacterium can only multiply within host cells and spread is primarily through inhalation of faecal dust. Recovered birds remain carriers and continue to shed the organism for up to 42 days after clinical signs subside. The same strain of the bacterium may cause mild disease or asymptomatic infection in one species, but severe or fatal disease in another species. The disease is not egg transmitted.
There is no effective vaccine available for use in birds. Treatment with tetracycline antibiotics will prevent mortality and shedding but cannot be relied upon to eliminate latent infection and therefore shedding may recur. Treatment of infected flocks with tetracyclines a minimum of two weeks prior to slaughter can effectively eliminate the transmission risk to processing workers. Effective biosecurity procedures are an important factor in preventing infections from occurring. The bacterium can survive in dried faeces for many months but is susceptible to heat and most disinfectants, however, it is resistant to acid and alkali.