Q fever is a bacterial infection caused by a bacterial pathogen, Coxiella burnetii, which is found worldwide except New Zealand. Coxiella burnetii is contagious and resistant to high temperatures, ultraviolet light and many disinfectants. It can survive on surfaces for up to 60 days. The CDC has ranked Coxiella burnetii as a “category B” bioterrorism agent.
Between 2000 and 2015, 904 cases of acute Q fever were recorded in England and Wales. The cases were mostly registered in Wales and the southwest of England.
Annually there are between 50–100 human cases of Q fever registered in the UK.
In the US the Q fever cases vary by state, with 38% of all cases reported in California, Texas and Iowa. According to CDC data, in 2017 there were 40 chronic Q fever cases and 153 acute Q fever cases were reported.
Q fever and its transmission
Q fever is a zoonotic disease and is usually spread from infected farm animals such as cattle, sheep, and goats. Infected animals with the Q fever appear healthy. Coxiella burnetii also infects cats, dogs and rabbits.
Q fever occurs at all times of the year with its peaks in spring and early summer.
Bacteria can be breathed in and/or are picked up by humans via the contact with infected animals’ milk, meat, blood, urine, feces, placenta, amniotic fluid, semen, wool or fur. When these infected substances dry up, Coxiella burnetii contained in these infected substances becomes a part of the barnyard dust, which is then inhaled by humans and enters their lungs.
Drinking unpasteurised/raw milk increases the risk of being infected with Q fever.
Some people do not get Q fever symptoms despite being infected, though the usual symptoms of Q fever include:
A sore throat
Muscle and joint pain
A high temperature
Symptoms usually develop 2-40 days after being infected.
Q fever in some cases can be severe, especially if one has a weakened immune system, impaired kidney function, blood vessel abnormalities or is pregnant.
The Q fever can cause pneumonia leading to acute respiratory distress and meningitis, brain inflammation.
In some cases people with Q fever develop a chronic Q fever, which is a life-threatening infection. Chronic Q fever can lead to endocarditis, heart valves infection, and if left untreated it can be fatal.
Apart from the heart, Q fever can also damage the liver, brain and lungs. Such cases of Q fever may require a hospital treatment and/or a long course of antibiotics.
Those in close contact with animals such as farmers, animal transporters, those visiting or working in abattoirs, butchers, animal researchers and vets are at a higher risk of contracting Q fever and should take precautions before, while and after their work with animals.
Pregnancy and Q fever
Pregnant women can get infected with the Q fever and this may affect their unborn baby.
Chronic Q fever is a life-threatening infection and in pregnant women it is linked with an increased risk of miscarriage, stillbirth and premature birth.
Pregnant women are advised to avoid close contact with the sheep, especially between January and April, the lambing season, as infections such as Q fever, chlamydiosis, listeriosis and toxoplasmosis could be passed on to them from the female sheep. Apart from the female sheep, goats and cows that have recently become mothers can also be carriers of these infections.
Although the risks are low, it is best to avoid close contact with sheep during the lambing season if you are pregnant and at other times of the year too as the risk is still present even when the lambing season is over.
Antibiotics is the main treatment.
Hospital treatment is required in severe cases. In cases of chronic Q fever a longer course of antibiotics will be required, and the doctor will prescribe the necessary.
Q-Vax vaccine is manufactured in Australia and is currently the only licensed Q fever vaccine for human use that offers immunity for many years.
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