Q fever (Coxiellosis)
About Q fever (Coxiellosis)
Q fever is a disease caused by the bacterium Coxiella burnetii, which can spread from animal to humans. It is typically found in livestock such as cattle, sheep, and goats but has also been found in various domestic and wild animals. Coxiella burnetii infection in animals is often without clinical signs, however, the bacteria can cause abortions (somtimes aboration storms on a single farm), stillbirths, or the birth of weak offspring in livestock. in humans, infection occurs through inhalation of contaminated aersols and dusts; and those likely to be in direct contact with birthing products such as vers and farm workers are at the greatest risk. other tansmissions routes, including foodborne, are possible. Human-to-human transmission, although rare, can occur under certain circumstances. Coxiella burnetii is highly resilient, surviving for months in harsh conditions, making prevention in animals challenging.
- Coxiella burnetii can cause reproductive losses in animals and disease in humans.
- The disease caused by C. burnetii is referred to as ‘Q fever’ in humans, and ‘coxiellosis’ in animals.
- The organism can be present in a herd or flock without causing any noticeable animal disease. However, in these herds/flocks there is still a risk of human infection. This may be the main reason for testing for C. burnetii on some farms, for example, open farms that are visited by members of the public.
- Coxiella burnetii can survive many months in the environment as an infectious spore-like small cell variant (SCV).
- SCV’s are resistant to heat, drying and disinfection. They can be carried several miles by the wind potentially spreading the disease over large distances.
- Coxiella burnetii has been associated with abortions and stillbirths in livestock (goats, sheep and cattle) but further work is required to investigate any potential links with metritis/endometritis or mastitis.
- Humans can become infected with C. burnetii if they inhale the bacteria. This could be through inhaling contaminated dust from bedding, animal hides, wool or furs, or bacteria which are aerosolised during birthing.
- The role of ticks in the transmission of C. burnetii is debatable and more work is required to confirm or deny any links.
- The infectious dose is very low, as few as one to ten organisms can cause infection.
- Most human infections are asymptomatic with others experiencing flu-like symptoms. In rare cases the disease can be much more serious, even fatal.
- Q fever/Coxiellosis is likely to be underdiagnosed due to the lack of clinical signs/symptoms in most animal and human infections.
- Vaccines are available for livestock in some countries including the UK. Vaccination can protect animals against reproductive losses, and reduces shedding of the bacteria from infected animals, thereby reducing transmission between animals and from animals to humans.