Q fever is a potentially lethal infectious zoonotic disease. Q fever can lead to myocarditis, encephalitis, and hepatitis. The main source of infection for humans are farm animals - cows, sheep, goats - as well as dogs and cats. What are the causes and symptoms of Q fever? What is the treatment?
Qfever is an acute infectious disease caused by bacteria - Coxiella burneti rickettsiae. In Poland, the disease was diagnosed in humans since 1956. The largest in Poland (and one of the largest in Europe) epidemics of Q fever in dairy cattle and humans (over 1000 patients) occurred in the then Zamość Province in 1983.
Q fever - routes of infection
The main source of infection for humans are farm animals - cows, sheep, goats - as well as dogs and cats. Human infection can occur through the oral route through unpasteurized milk of cows, sheep, goats and cheeses made from it.
The sources of infection may be, among others contaminated wool, milk, faeces of infected animals and their urine, dust in rooms where sick animals are housed, contaminated water and animals such as cats in the perinatal period.
Infection can also occur during milking, meat processing, sheep shearing, and leather and wool processing. Infected animals in the perinatal period are also a threat (infection occurs through contact with aborted fetuses, placenta, amniotic fluid or vaginal mucus of animals).
Another source of Coxiella burnetii are ticks (due to sucking blood during bacteremia in infected animals), tick feces and feces of domestic ruminants, which when dried as dust or aerosols with germs are inhaled by animals or humans.
Human-to-human horizontal infections are very rare, mainly in hospitals, where patients infect each other through the sputum released by violent coughing. There is also a risk of infection to the fetus from the mother.
People who come into contact with farm animals or their products are particularly vulnerable. They are farmers, veterinary and zootechnical service, employees of slaughterhouses, meat processing plants, dairies, tanneries, leather and wool industries.
Q fever -symptoms
In humans, Q fever is distinguished between acute and chronic course. Acute symptoms vary from patient to patient:
- increase in body temperature - occurs frequently (in about 90% of patients)
- headache (in about 50% of patients)
- muscle pain (37%) joint pain (27%)
- cough (in 34%)
Cardiac disorders occur in 2% of patients who experience acute Q fever, including myocarditis, which may be fatal.
Neurological symptoms (meningitis or encephalitis) may appear, especially if humans are infected with goats.
One of the most common complications is atypical pneumonia, which, if left untreated, can lead to acute respiratory distress syndrome (ARDS)
The chronic form of Q fever in humans develops within months or even years from the time of infection. The result is
- 75 percent cases of endocarditis. The disease is accompanied by pathological changes in the heart valves and / or immunosuppression
- arthritis and bone marrow inflammation may develop
- chronic hepatitis may develop
In the case of infection of a pregnant woman, C. burnetii locates in the uterus and in the mammary glands, which endangers both the mother and the fetus or newborn. There may be a miscarriage or premature birth with a baby with a low body weight and a low level of viability.
Q fever - diagnostician
If Q fever is suspected, an indirect immunofluorescence test (IFT) is performed to detect specific Phase I antibodies (IgM and IgG) dominant in the chronic phase of the disease and antibodies to Phase II antigen that occur in the acute course of Q fever .
Molecular biology tests are performed more and more often to confirm Coxiella burnetii infection. polymerase chain reaction - PCR.
Q fever - treatment
treatment of Q fever is based on antibiotic therapy (e.g. with doxycycline, ciprofloxacin) for 2-3 weeks and, in the event of complications, on combining appropriate antibiotics and using them for a minimum of 2-3 years.
1. Truszczyński M., Q fever, animal disease and zoonosis - practical aspects, "Życie Weterynaryjne" 2010
2. Galińska E. M., Żukiewicz-Sobczak W., Chmielewska-Badora J., Q fever in humans - etiology, diagnostics, clinical forms, "European Journal of Medical Technologies"2014