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Q FEVER
Q Fever is a zoonosis – a bacterial infection that can cause illness in people, particularly those
working with livestock. The infectious agent is the coxiella burnetti bacteria. It was first identified
in abattoir workers in Brisbane, Queensland in 1937. The “Q” stands for “query” as, when it was
first identified, the causative nature was unknown.
Q Fever can spread to humans from animals, most commonly from livestock such as sheep,
cattle, goats and other domestic animals. The primary mode of transmission is the inhalation of
windblown contaminated aerosols, particularly from infected sheep placentas on open farmland.
The infectious airborne particles can travel significant distances and are highly resistant to
environmental conditions, often surviving in the open air for many months. Infection can also
result from the inhalation of dust, contact with unpasturised contaminated milk, meat and wool.
Although Q Fever remains relatively rare with only about seventy cases in the UK per year, it is
actually the world’s most infectious disease because infection can result from the inhalation of
single bacteria. As a result Q Fever has been considered by various governments as a potential
biological threat.
In animals, the infection is largely asymptomatic. In humans, the incubation period is usually two
to three weeks with the condition falling into two categories:
1. Acute Q Fever.
2. Chronic Q Fever (that is where the condition persists for more than six months).
In Acute Q Fever, symptoms are typically flu like with fever, myalgia and a dry cough but in some
individuals, they can have mild pneumonia with symptoms of hepatitis.
In cases of Chronic Q Fever which are more likely to occur with those with a pre existing health
condition, making them more susceptible to infection, the most common symptom is
endocarditis (that is, the inflammation of the inner lining of the heart), which if left untreated can
result in heart failure.
Cases can occur in people who are occupationally exposed. Those occupations, which are “at
risk” include farmers, shearers, tannery workers, abattoir workers and meat packers.
If correctly diagnosed at an early stage, antibiotics can shorten the course of the symptoms. It is
thought that once infected, a person develops a life long immunity against re-infection.
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