What is Q Fever?

board of animal health

Reportable Disease of the Month

Q Fever

What is it?

A zoonotic disease mainly affecting mammals including sheep, goats and cattle. The disease has also been reported in various other mammals, birds and reptiles. The causative agent of the disease is the bacteria Coxiella burnetii. Q fever is found in almost every country, and was first discovered in Australia. The “Q” stands for query because scientists couldn’t determine the root cause of the disease (Coxiella burnetii bacteria) when it was first discovered.

How is it transmitted?

The majority of infections are believed to come from direct contact between infected and non-infected animals. Animals inhale or ingest infected materials or secretions like saliva, milk, urine, feces, birthing fluids, and afterbirth. Transmission may also be a result of contact with contaminated objects (fomites). The bacteria have also been found to circulate between wild animals via ticks, which can transmit the disease through a bite.

What are the clinical signs?

The majority of infected animals do not exhibit significant clinical signs. The most common indicator of a Q Fever infection in affected animals is late term abortion, stillbirth or the birth of small or weak offspring.

How is it diagnosed?

Samples can be collected from tissues from sick animals, aborted fetuses and afterbirth and submitted to a diagnostic laboratory to identify C. burnettii bacteria. Additionally, collecting blood samples on whole herds can identify if the disease is, or has been, present in the group by testing for an antibody response. If tested animals show a positive antibody response, it means members of the herd were infected at one point in time.

Is there a risk to people?

Yes, Coxiella burnetii can become aerosolized and inhaled by people, especially those assisting an infected animal as it gives birth. Veterinarians and livestock handlers have a greater chance of exposure than the general public. However, anyone is at risk through consumption of infected raw milk, and via the bite of an infected tick. Pasteurization of milk has been proven to kill the organism, and pasteurized products are safe to consume. Women who are infected during pregnancy may have a higher risk of complications.

How can it be prevented?

Precautions should be taken to separate pregnant livestock from the rest of the herd. Animals that have experienced an abortion or a stillbirth should be isolated and separated from the remaining pregnant animals in the herd. Livestock handlers should regularly clean and disinfect birthing areas and properly dispose of afterbirth because C. burnetii can remain viable for prolonged periods in the environment and is extremely resistant to heat, drying, and many common disinfectants. The bacteria can survive on equipment, so routine cleaning should be a standard precaution. Ticks can carry the bacteria, and minimizing livestock exposure to tick habitat and routinely examining animals for ticks can reduce risk of this disease. Vaccines are available in countries where the disease is an ongoing threat.

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