What is Q fever and is it dangerous?

The article is expertly consulted by Master. Doctor Nguyen Thi Nhat - Doctor of Infectious Diseases - Department of Examination & Internal Medicine - Vinmec Hai Phong International General Hospital. The doctor has more than 10 years of experience in the field of artificial kidneys, and in the field of infectious diseases, examining and managing patients with kidney disease and infectious diseases.

Q fever is a zoonotic disease that is transmitted to humans by direct contact or by respiratory transmission from an infected host. Fortunately, Q fever is highly self-healing, and immunity can provide lifelong protection.

Q fever (Q Fever; Query fever) is a disease of animals (cow, sheep, goats...) that is transmitted to humans through feces, urine, milk, placenta. The disease in humans is usually acute (sometimes turning chronic).
The causative agent is Coxiella burnetii (R. burnetii) - a Gram-negative cocci, smaller than other Rickettsii (0.3 - 0.7 m long). This is a spore-forming bacterium with high resistance in the periphery, surviving for more than 1 month on chilled fresh meat, 7-10 months on wool at 15-200C, over 40 months in skimmed milk at temperature. indoor temperature; Bacteria are killed by Lysol 1%, formaldehyde 2%, hydrogen peroxide 5%.
Animals infected with pathogens such as sheep, domestic cats, ... often have no symptoms but excrete a lot of bacteria in feces, urine, milk, especially placenta every time they give birth (sick sheep placenta) contain up to 1,000,000,000 bacteria/gram of tissue). These wastes are factors that transmit bacteria from animals to humans and between animals.
The rare disease is transmitted directly from sick people to normal people, including through the respiratory tract. However, bacteria can be transmitted from animals to humans through the main modes of transmission:
Due to direct occupational contact with skin, wool, meat, placenta, amniotic fluid, urine, feces of sick animals; or in contact with the patient's clothing or waste. By inhalation: inhalation of dust containing bacteria from the waste of diseased animals in factories, on grasslands, etc.; bacteria-containing molecules can fly as far as 1.5 miles (2.4 km); There are opinions that this is the common method (in developed countries). C.burnetii can be used as an aerosol biological weapon. Rarely, the disease is transmitted directly from an infected person to a healthy person through the respiratory tract. By eating or drinking: By eating undercooked meat, or raw milk of sick animals. However, this mode of transmission is more rare.

Incubation period is about 18 - 20 days (14 - 39 days); After that, the disease has a sudden onset, with flu-like syndrome with high fever, headache/eye socket, muscle and joint pain, sweating, cough, even bleeding, pulmonary symptoms are not clear, picture on film X-rays often show atypical pneumonia.
Disease progression is variable but usually mild, with recovery by day 15. Mortality rate is less than 2%. Some cases are severe, more rarely, with complications of endocarditis lasting up to 2 years (accounting for 50% of patients with valvular disease); chronic granulomatous hepatitis; neurological syndrome; thrombophlebitis,..

Q fever appears in many countries around the world. The actual incidence is even higher than reported because there are many mild cases, missed detection, and inadequate testing at the facility.
The epidemic is circulating in areas where there are animals containing pathogens. The disease has occurred in risk points such as cattle farms (cattle, goats, sheep), meat, milk, wool, wool processing factories..., Medical and Veterinary Research Institutes, especially where sheep are used for research.

Vietnam is currently a country with a focus on agriculture, raising and developing cattle in rural areas and farms. These animals, such as cows, goats, sheep, or some other animals such as buffaloes, cows, pigs, fish... are at risk of becoming pathogens in nature.
Fortunately, every individual gets sick. After recovering from the disease, immunity is likely for a lifetime; Cellular immunity is longer lasting than humoral immunity.
Q fever is considered the most common self-healing disease; In many areas, up to 11-12% of the population has antibodies to C.burnetii without a history of colds, pneumonia,...

Reference source: Department of Preventive Medicine, Ministry of Health