Q fever

The symptoms of Q fever can vary significantly from person to person. Many individuals infected with Q fever may remain asymptomatic or show no symptoms for an extended period. Approximately 50% of those infected with the bacteria will develop symptoms. For symptomatic cases, symptoms typically appear between two to three weeks after exposure to the bacteria. The severity of symptoms can range from mild to severe, depending on the level of infection. Signs and symptoms include:

• High fever (up to 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 is caused by the bacterium Coxiella burnetii. It is primarily found in cattle, sheep, and goats. The bacteria can pass into the 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
• 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
• Individuals involved in animal studies or research

The bacterium is highly infectious and remains viable in dust and stool for months. Even a brief exposure to the bacterium can result in infection. However, person-to-person spread is extremely unlikely. Very rarely, Q fever can spread through:

• Blood transfusion
• Transmission from a pregnant woman to her fetus
• Sexual intercourse
• The bite of an infected tick

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:

1. Occupation

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

2. Location

Being located close to a farm or farming facility, or living on a farm, may increase your risk of the disease.

3. Season

Although there is no specific time of year when one can get infected, it seems to be more common in the spring and early summer.

4. Consumption of Unpasteurized Milk or Dairy Products

Rare cases have been reported from consuming infected raw, unpasteurized milk or dairy products.

5. Immunocompromised Individuals

A weak immune system can increase the risk for a severe form of the infection. Common reasons for a weakened 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 such as:

• Influenza
• Other viral infections
• Salmonellosis
• Malaria
• Hepatitis
• Brucellosis

Later, it resembles many forms of bacterial, viral, mycoplasmal, and other atypical pneumonias. Therefore, the diagnosis of the disease can be difficult based on symptoms alone. When a patient is symptomatic and shows flu-like symptoms, your doctor may suspect Q fever if you live or work in an environment that puts you at high risk for exposure. Your doctor might ask about the whereabouts of your close contacts or similar exposure. Based on your answers, your doctor might recommend blood tests along with additional tests, which include:

• Antibody test: Individuals infected with Q fever develop specific antibodies, including immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM). Measuring the levels of these 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 detect 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 specimens. 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): This test checks for low red blood cells (anemia) and levels of white blood cells.
• Liver function or kidney function tests: These tests 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, including:

• 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 heartbeat and pumping of blood. Your doctor may recommend an ECG to identify if the heart valves are healthy and confirm the absence of heart disease.

Tests may also be conducted to rule out other causes for symptoms, such as tick-borne diseases or more common viral or bacterial infections.

If your occupation involves close contact with cattle, vaccination is the best preventive measure. However, the Q fever vaccine is not available globally. If you are not vaccinated, Q fever can primarily be prevented by exercising caution when in close contact with cattle, sheep, pigs, and horses.

Vaccination

There is a vaccine available for Q Fever named Q-VAX® that can help prevent the occurrence and severity of the infection. However, it is only commercially available in Australia. Pre-vaccination screening with skin and blood tests should be conducted to identify preexisting immunity to Q fever, as vaccinating individuals who already have immunity can cause severe local reactions. If you are not vaccinated and are at high risk for Q fever, you must follow these preventive measures:

• Disinfect and decontaminate areas in the workplace or home where exposure to the infection is suspected.
• Avoid unnecessary contact with animals, especially those giving birth.
• Dispose of all birth materials properly after a livestock animal has given birth.
• Prevent dogs, cats, birds, and other animals from scavenging birthing products.
• Wash your hands thoroughly at regular intervals.
• Perform regular tests and inspections on animals and farms.
• Avoid consumption of unpasteurized milk or milk products.
• Pregnant women should avoid assisting with livestock births.
• Minimize or restrict airflow from facilities that house animals to residential areas.
• Quarantine infected and exposed animals.
• Practice safe workplace protocols and procedures to minimize the risk of infection.

The severity of the disease and symptoms plays a key role in deciding the treatment regime for Q fever. In most cases, asymptomatic individuals and those with mild infections typically resolve within a few weeks without any treatment. However, in the case of a severe infection, your doctor will need to prescribe medication—an antibiotic.

1. Antibiotic therapy

   Doxycycline is the most commonly prescribed antibiotic for treating Q fever. Individuals with chronic Q fever are usually prescribed a combination of antibiotics for a duration of 18 months. Once chronic Q fever is treated, your doctor may ask you to return for follow-up tests to confirm the absence of recurrence.

2. Anti-inflammatory drugs

   Some individuals may not respond to antibiotic treatment; in such cases, the doctor will prescribe anti-inflammatory drugs. Hydroxychloroquine, a medication used for treating malaria, has been found effective against Q fever. If you are pregnant and exhibit symptoms of the disease, your doctor will recommend antibiotic treatment, with the type of medication varying depending on your condition.

3. Multiple/combination drugs

   Chronic Q fever, the severe form of the infection, can be challenging to treat. Endocarditis, which is inflammation of the inner lining of the heart's chambers and valves, may require the patient to undergo multiple drug treatments. Individuals with heart conditions need 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, especially 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 most cases, the symptoms of Q fever are mild flu-like and resolve within a few days to a week. If Q fever persists or recurs, it can cause complications that severely damage organs such as the heart, lungs, liver, and brain. Chronic Q fever is the severe form of Q fever that develops months or years after the initial diagnosis. Complications caused by chronic Q fever include:

• Pneumonia, affecting 30%-50% of patients, which can lead to acute respiratory distress and may sometimes cause a medical emergency.
• Hepatitis (inflammation of the liver).
• Myocarditis or endocarditis (inflammation of the heart).
• Meningitis (inflammation of the membranes around the spinal cord and brain) or encephalitis (inflammation of the brain).
• Osteomyelitis (bone inflammation).
• Acalculous cholecystitis (inflammation of the gallbladder).
• Persistent fatigue, also known as post-Q fever fatigue syndrome, which lasts more than a year after the infection.
• Pregnancy complications such as miscarriage, low birth weight, premature birth, and stillbirth may occur due to the 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.

In some cases, people may experience 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.

Q fever and other diseases

Below is a list of some other bacterial diseases that cause similar symptoms, making it important to understand how these diseases are similar to Q fever yet 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. Common symptoms include severe pneumonia, chills, fever, cough, and sharp pain in the side of the chest.
• Rocky Mountain spotted fever is a bacterial disease caused by R. rickettsii. The disease is characterized by mild to severe 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 be transmitted to humans. The infection is caused by bacteria belonging to the genus Brucella. Common symptoms include fever, muscle pain, headache, loss of appetite, profuse sweating, and physical weakness. Similar to Q fever, brucellosis can be prevented by avoiding the 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 is transmitted when a diseased animal bites a human or when a human is bitten by a tick or fly.