How does infection occur?
The main route of transmission is airborne dust. The pathogen is concentrated in the amniotic fluid, placenta, urine and milk of infected animals, enters the litter and soil, and is then transported over considerable distances with dust and wind. It only takes a small amount to inhale to make you sick. Less commonly, infection occurs through consumption of raw milk and unpasteurized dairy products. The infection is practically not transmitted from person to person. At risk are livestock farmers, veterinarians, slaughterhouse and wool processing workers, as well as residents of areas near farms.
- Inhalation of dust containing pathogen
- Contact with amniotic fluid during lambing and calving
- Raw milk and unpasteurized products
- Working with wool and skins
- Living near livestock farms
- Transmission between people is extremely rare
Acute symptoms
The incubation period is usually 2–3 weeks. The disease begins suddenly with high fever, severe headache, especially in the forehead and behind the eyes, severe weakness, muscle pain and profuse sweating. Often accompanied by a dry cough and chest pain due to pneumonia, which can occur secretly and be revealed only in the image. Some patients develop hepatitis with liver enlargement and elevated liver enzymes. The rash is rare, which sets Q fever apart from many other animal-borne infections.
- Sudden high fever and chills
- Severe headache behind the eyes
- Severe sweating and weakness
- Muscle and joint pain
- Dry cough, pneumonia
- Liver enlargement, hepatitis
- Rash is rare
Chronic form
Chronic Q fever develops in a small proportion of those infected, sometimes months or years after the acute episode, sometimes without it. The most common and dangerous manifestation is endocarditis, damage to the heart valves, which occurs without significant symptoms: prolonged low fever, weakness, weight loss, sweating, gradual increase in heart failure. Particularly vulnerable are people with existing defects, prosthetic valves, vascular prostheses and aneurysms, as well as immunocompromised patients and pregnant women.
- Heart valve endocarditis
- Infection of vascular grafts and aneurysms
- Prolonged low-grade fever
- Weight loss and fatigue
- Chronic fatigue after acute form
- Risk of pregnancy complications
Diagnostics
Diagnosis is rarely made by symptoms alone because they are nonspecific. The combination of the clinical picture with an indication of contact with animals, living near farms or drinking raw milk is crucial. The diagnosis is confirmed by serological studies, determining antibodies of two phases: their ratio helps to distinguish an acute infection from a chronic one. In the early period, blood PCR is used. Additionally, a complete blood count, inflammation indicators and liver enzymes are assessed, an x-ray of the lungs is performed, and if endocarditis is suspected, an echocardiography is performed.
- Detailed collection of animal exposure data
- Serological tests for antibodies
- Early blood PCR
- Complete blood count, CRP
- Liver tests
- Chest x-ray
- Echocardiography for suspected endocarditis
Treatment and prevention
The acute form is treated with antibiotics that are effective against intracellular pathogens; the drug, dose and duration are determined by the doctor, the course is usually about two weeks. Treatment started in the first days of the disease significantly shortens its duration. The chronic form requires combination therapy lasting many months with regular monitoring of tests and echocardiography, and sometimes surgical treatment of the valve. Prevention consists of protection at work and avoidance of raw milk. Pregnant women should avoid contact with lambing and calving animals.
- Antibiotic therapy as prescribed by a doctor
- Long-term combination therapy for chronic form
- Monitoring antibodies and echocardiography after recovery
- Pasteurization or boiling of milk
- Protective equipment when working with animals
- Restricting access of strangers to lambing areas
- Particular caution in people with heart defects and prostheses