Q fever is a zoonotic disease that is transmitted from animals to humans. It is caused by the bacterium Coxiella burnetii which is mainly found in cattle, sheep, and goats. The bacteria is present in the milk, urine and feces of the infected animals. Moreover, large numbers of bacteria are shed in the birth products like placenta and amniotic fluid during birthing. When these products dry over time they contaminate the air. Inhalation of this contaminated air can cause infection in humans.
Q fever is mostly considered as an occupational disease associated with slaughterhouse workers, dairy workers, farmers, veterinarians or researchers involved in animal studies. The infection causes flu-like symptoms however, many people do not have symptoms at all or could be asymptomatic. If the Q fever persists or reoccurs, it can cause complications that can severely damage organs such as heart, lungs, liver, and brain.
The disease is prevalent globally, however, remains under-reported in many countries such as India. The disease can be prevented by avoiding close contact with animals when they are birthing, and practicing good hygiene at the workplace (farms and barnyards).
The infection can cause two types of Q fever that vary by severity and nature. The two types are:
Acute Q fever
This form of Q fever usually begins two to three weeks after exposure to the bacterium. Acute Q fever is characterized by flu-like symptoms which include high fevers, chills, muscle pain, and headaches. Acute Q fever is usually self-limited which means it can resolve itself without treatment.
Chronic Q fever
This form of Q fever may occur months to years after acute disease or without a previous history of acute Q fever. It has been observed that predisposing conditions such as pre-existing heart valve or vascular abnormalities or an immunocompromised immune system increases the risk for chronic Q fever.
Q fever is caused by the bacterium Coxiella burnetii. It is primarily found in cattle, sheep and goats. The bacteria pass into milk, urine and feces of infected herd animals. Infected aerosols can also travel, affecting people living downwind of an infected goat or sheep farm.
Other causes include contact with contaminated clothing, wool, hides or straw, dressing infected animals or consuming infected raw or unpasteurized dairy products. Usually, Q fever is an occupational disease seen in slaughterhouse and dairy workers, livestock farmers, rendering-plant workers, herders, woolsorters, veterinarians or those involved in animal studies or research.
The bacterium is highly infectious in nature and remains viable in dust and stool for months. Even a quick exposure to the bacterium can cause an infection. However, person-to-person spread is extremely unlikely. Very rarely, Q fever can spread through blood transfusion, from a pregnant woman to her fetus, through sexual intercourse or by the bite of an infected tick.
The symptoms of Q fever can vary significantly from person to person. Many people infected with Q fever do not show symptoms for a long time or are asymptomatic. About 5 out of 10 people infected with the bacteria get sick.
For symptomatic cases, symptoms show between two to three weeks after exposure to the bacteria. Symptoms can be mild or severe depending on the level of infection.
Signs and symptoms include:
High fever (upto 105°F)
Severe headache
Malaise or general feeling of being unwell
Fatigue
Chills or sweats
Non-productive cough
Shortness of breath
Muscle aches
Nausea
Vomiting
Diarrhea
Chest pain while breathing
Stomach pain
Drowsiness or confusion
Weight loss
Sensitivity to light
Jaundice
Q fever can infect men more often than women and adults more often than children. However, it has been commonly reported in elderly males. Certain factors can increase your risk of getting infected with Q fever, which include:
The following are at high risk as they are exposed to animals and animal products:
Workers in cattle, sheep, and goat abattoirs
Farmers, stockyard workers, and livestock transporters
Dairy workers
Wool shearers and sorters
Agricultural college staff and students
Wildlife and zoo workers exposed to high-risk animals
Veterinarians, veterinary nurses, and students
Tanning and hide workers
Professional dog and cat breeders
Laboratory workers handling veterinary products or working with Coxiella burnetii
Others who are exposed to cattle, camels, sheep and goats or their products
If you are located close to a farm or farming facility or live on a farm that may increase your risk towards the disease.
Though there is no specific time of year when one can get infected, it seems to be more common in the spring and early summer.
Not often, but rare cases were reported by consuming infected raw, unpasteurized milk or dairy products.
A weak immune system can increase the risk for a severe form of the infection. Some of the common reasons that lead to weakening of the immune system include:
Malnutrition
Certain diseases such as acquired immunodeficiency syndrome (AIDS) and cancer
Genetic disorders
Excessive consumption of medicines such as steroids, anti-cancer drugs, and painkillers
Lifestyle habits such as smoking, excessive drinking, and unhealthy eating
In case of an infection, not every patient shows symptoms and many patients can be asymptomatic. Moreover, symptoms do not readily suggest the diagnosis of Q fever. In the early stages, Q fever resembles infections like influenza, other viral infections, salmonellosis, malaria, hepatitis, and brucellosis. Later, it resembles many forms of bacterial, viral, and mycoplasmal and other atypical pneumonias. Therefore, the diagnosis of the disease can be difficult at times based on the symptoms alone.
When a patient is symptomatic and shows flu-like symptoms, your doctor may suspect you to have the infection if you live or work in an environment that can put you at high risk for exposure. Your doctor might ask you about the whereabouts of your close contacts or similar exposure.
Based on your answers, your doctor might recommend you to get some blood tests along with additional tests done. The tests include:
Antibody test: Individuals infected with Q-fever develop specific antibodies against Q fever including immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM). Measuring the levels of these classes of antibodies can help confirm a diagnosis of Q fever.
During the acute phase of Q fever, IgG and IgM antibodies may be detected. In chronic Q fever, IgG or IgA levels may be detected.
The most common serological tests for Q fever that detects the presence of specific antibodies or antigens in the blood or other fluids are:
Indirect immunofluorescence
Complement fixation
Enzyme-linked immunosorbent assay (ELISA)
Polymerase chain reaction (PCR) test: A PCR test is a highly sensitive test to detect the presence of C. burnetii infection in biopsy specimen. It can detect infection earlier than the antibody test, but it is less readily available. However, a negative PCR result does not rule out the diagnosis.
Complete blood count (CBC): It is done to check for low red blood cells (anemia) and levels of white blood cells.
Liver function or kidney function tests: They are done to diagnose any liver or kidney malfunction.
Prolonged infection with the bacteria can eventually damage the lungs and heart. The doctor might suggest a few imaging tests to confirm if the infection has caused damage to other organs.
Chest X-rays: Q fever can damage the lungs and cause pneumonia in some people. A chest X ray produces images of the heart, lungs, blood vessels, and bones of the chest, spine, and airways. The test confirms the presence of fluid in or around the lungs, which can be indicative of a concern. The chest x-ray can be performed to see if the lungs are healthy and have no obstruction.
Echocardiography: An echocardiography is a test that uses sound waves to produce images of the heart called an echocardiogram (ECG). The images show the heart beat and pumping of blood. Your doctor may recommend you to get an ECG done to identify if the heart valves are healthy and confirm the absence of a heart disease.
Tests to rule out other causes for symptoms such as tick-borne disease or more common viral or bacterial infections.
If your occupation involves close contact with cattle, vaccination would be the best preventive measure. However, the Q fever vaccine is not available globally. If you are not vaccinated, primarily, Q fever can be prevented by being extra cautious if you are in close contact with cattle, sheep, pigs, and horses.
There is a vaccine available for Q Fever named (Q-VAX®) which can help prevent the occurrence and severity of the infection. But it is only commercially available in Australia.
However, pre-vaccination screening with skin and blood tests should be done to identify preexisting immunity to Q fever as vaccinating people who already have immunity can cause severe local reactions.
If you are not vaccinated and are at a high risk for Q fever you must follow these preventive measures:
Disinfect and decontaminate areas in the workplace or house where you suspect an exposure to the infection
Avoid unnecessary contact with animals, especially the ones giving birth
Dispose of all birth materials after a livestock animal has given birth properly
Avoid dogs, cats, birds, and other animals from scavenging birthing products
Wash your hands properly at regular intervals
Perform regular tests and inspection on animals and farms
Avoid consumption of unpasteurized milk or milk products
Pregnant women should avoid helping with livestock birth
Minimize or restrict the airflow from facilities that house animals to residential areas
Quarantine infected and exposed animals
Practice safe workplace practices, protocols and procedures to minimize risk of infection
If you are asymptomatic or showcase mild infection, the symptoms may resolve within a few weeks without any treatment. However, if you have a severe infection and you have an underlying heart condition or are immunocompromised, you are recommended to see a doctor at the earliest. Also, if you are pregnant, consult a doctor.
Specialists that can help to manage and treat Q fever include:
General physician
Infectious disease specialist
The severity of the disease and symptoms plays a key role in deciding the treatment regime for Q fever.
In most cases, asymptomatic cases and people with a mild infection showing symptoms usually resolve within a few weeks without any treatment. However, in case of a severe infection your doctor will have to prescribe a medication – an antibiotic.
Doxycycline is the most commonly prescribed antibiotic for treating Q fever. People with chronic Q fever usually are prescribed a combination of antibiotics for a span of 18 months. Once the chronic Q fever is treated, your doctor may ask you to come back for follow up tests to confirm the absence of recurrence.
Some individuals might not respond to the antibiotic treatment, in that case, the doctor will prescribe some anti-inflammatory drugs. Hydroxychloroquine, a drug used for treating malaria, has been found to be effective against Q fever.
If you are pregnant and show symptoms of the disease, your doctor will recommend an antibiotic treatment. The medication type may vary depending on your condition.
Chronic Q fever, the severe form of the infection, can be difficult to treat. Endocarditis, inflammation of the inner lining of the heart's chambers and valves, may require the patient to undergo multiple drug treatments. People with heart conditions require an early diagnosis and antibiotic treatment for at least 18 months.
Q fever is a bacterial infection and in most cases the infection is self limited. In case of severe symptoms, the disease can be managed using antibiotics and anti-inflammatory drugs. Some tips to manage the symptoms of Q fever include:
Stay home and avoid contact with anyone.
Eat healthy, nutrient dense and easy to digest food.
Consume fluids (water, coconut water, electrolytes, soups, and fresh juices) to stay hydrated, if you have diarrhea as one of the key symptoms.
Take plenty of rest as it will help the body fight against the infection and cope with the condition.
In some cases, people may get a reinfection or the severity of the disease may lead to chronic Q fever and related complications. Here are some tips that will help you get better:
If you have mild flu-like symptoms, your symptoms may resolve in a few weeks (1-2). If you don’t feel better, book an appointment and see your doctor.
If you are immunocompromised or have a heart or lung condition, take extra care until the symptoms resolve. Your doctor may even call you frequently for follow up tests even after the infection has been treated.
Below is a list of some other bacterial diseases which cause similar symptoms and therefore it is important to understand how these diseases seem to be similar to Q fever yet are different.
Legionnaires’ disease is a rare infectious bacterial disease caused by Legionella pneumophila. The infection is contracted by inhaling contaminated water from showers and whirlpool baths. Some of the common symptoms of the disease include severe pneumonia, chills, fevers, cough and a sharp pain in the side of the chest.
Rocky mountain spotted fever is a bacterial disease caused by R. rickettsii. The disease is characterized with mild to serious symptoms such as headache, fever, chills, muscle aches (myalgia), joint pain (arthralgia), extreme exhaustion (prostration), and/or a characteristic skin rash.
Brucellosis is an infectious disease that affects livestock and can get transmitted to humans. The infection is caused by the bacteria that belongs to the genus Brucella. Common symptoms of the infection include fevers, muscle pain, headache, loss of appetite, profuse sweating, and physical weakness. Similar to Q fever, brucellosis can be prevented by avoiding consumption of unpasteurized milk.
Tularemia is a bacterial infection that commonly affects small mammals such as rabbits, rodents and hares. It is a highly transmissible disease and gets transmitted when the diseased animal bites a human or it gets bitten by a tick or fly.
In most cases, the symptoms of Q fever are mild flu-like and resolve within a few days to week. If the Q fever persists or reoccurs, it can cause complications that can severely damage organs such as heart, lungs, liver, and brain. Chronic Q fever is the severe form of Q fever which develops months or years after the first diagnosis. Complications caused due to chronic Q fever are:
Pneumonia, which affects 30%-50% of patients can lead to acute respiratory distress and may sometimes cause a medical emergency
Hepatitis (inflammation of the liver)
Myocarditis or endocarditis (inflammation of heart)
Meningitis (inflammation of the membrane around the spinal cord and brain) or encephalitis (inflammation of the brain)
Osteomyelitis (bone inflammation)
Acalculous cholecystitis (inflammation of the gallbladder)
Persistent fatigue (also called post-Q fever fatigue syndrome, which lasts more than a year after the infection)
Pregnancy problems such as miscarriage, low birth weight, premature birth, and stillbirth could be seen due to severity of Q fever
Many patients with Q fever may also develop long term complications such as chronic and persistent fatigue.
Since Q fever is an infectious bacterial disease, it can only be treated with antibiotics. There are no alternative therapies available for the disease.
