What Is Q Fever

• Fever
• Exhaustion
• Chills
• Severe headache
• Muscle pain

Does anyone in the audience recognise or have any of these symptoms? Do they resemble COVID-19, the flu or Q fever in any manner? Are you seeking information about Q fever with identical symptoms? Let's delve into the subject in detail for a deeper comprehension of this zoonotic disease.

Q fever is an infection caused by the bacteria Coxiella burnetii. All domestic and wild animals, including cattle, sheep, and goats, can transmit it to people. The disease may pass to people who do not interact with animals.

Even though persistent Q fever only affects a small percentage of the population, a thorough understanding of the condition can help avoid serious complications.

Overview

Except in New Zealand, Q fever is a zoonotic disease (humans contract the sickness from animals) that affects people worldwide. Coxiella burnetii, a tiny Gram-negative bacterium, strictly intracellular that can solely be isolated from eukaryotic cells, is responsible for the illness it causes. Rickettsia is no longer an accepted category for the bacterium. It was reclassified as Proteobacteria and placed in the same phylum as Legionella species as a result of molecular research. It grows within these cells in an acidic vacuole with a pH of 4.8. It can produce spores, which explains why it can endure harsh conditions for a long time and has a remarkable capacity to withstand physiochemical agents. Stages I and II are the two antigenic stages of Coxiella burnetii. Animals have it in phase I, which is very contagious; passage in cell culture or fertilised eggs causes a shift in the surface lipopolysaccharides, phase II. Phase II is far less dangerous than Phase I. Numerous genes can play a part in host-cell regulation, intracellular trafficking, adhesion, invasion, and detoxification.¹

Australia and the United States were among the first countries to identify Q fever as a disease affecting people in 1935 and the early 1940s respectively. The "Q" stands for "query" and was used when it was unclear what was causing it. Nature's reservoirs for C. burnetii include numerous kinds of ticks, birds, and mammals. Animals with a latent C. burnetii infection usually continue to discharge bacteria into the environment. At the time of giving birth, however, there is intermittent high-level shedding in females, and millions of bacteria are released per gram of placenta.

It is difficult to determine the prevalence of Q fever in most countries because it is rarely an illness necessary to be mentioned. Recent epidemiological studies, however, indicate that some nations, including France, the United Kingdom, Italy, Spain, Germany, Israel, Greece, and Canada (Nova Scotia), as well as many others where Q fever is widespread but goes undiagnosed due to insufficient surveillance of the disease, might want to consider it as a health concern. For people interacting with domestic animals like goats, sheep, and cattle daily, Q fever remains a concern. Nevertheless, there has been an increase in the overall number of cases recorded in urban dwellers who have had infrequent contact with infected pets like infected dogs and cats.^2,3

Causes of Q fever

Typically, the bacteria responsible for Q fever in the air or dust gets inhaled by a person. Despite domestic and wild dogs and cats, feral pigs, horses, rabbits, rodents, camels, birds, foxes, ticks, and native Australian wildlife (including bats, kangaroos and bandicoots) may all harbour the bacteria. Cattle, sheep, and goats are the most frequent sources of infection. Many times, infected animals show no symptoms. The bacteria can be identified in large amounts in the placenta, birth fluids, urine, faeces, and even in the blood or milk of animals infected with or carrying the germs. The wind can carry the bacteria over several kilometres and persists for a long time in the dust and soil.

Humans get infected by:

• Breathing in the bacteria that is in the dust or air while giving birth, butchering, or killing diseased animals, mustering, shearing, or transporting animals, mowing grass contaminated by infected animal excretions, visiting, living, or working in/near a high-risk industry and working with infected animals, infected animal tissues, fluids, or excretions, as well as with animal products or materials that have been contaminated.
• Cuts or needlestick wounds from working with infected animals are examples of direct contact with infected animal tissue or fluids on broken skin.
• Intake of raw, unpasteurised milk from contaminated sheep, goats, or cows.^4,5

Signs and symptoms of Q fever

Flu-like initial (acute) symptoms appear three to thirty days following exposure. Q fever fatigue syndrome (QFS), which affects some patients more than a year after first contact, causes continued symptoms. Others exhibit signs of chronic Q fever, a more severe infection. With an average of two to three weeks, the incubation period for Q fever ranges from two to 48 days.

Acute Q fever symptoms might vary greatly but are typically flu-like. It may result in hepatitis, pneumonia, encephalitis, or meningitis, which are all inflammatory conditions of the liver. You might experience the following symptoms:

• Fever 
• Severe fatigue
• Chills
• Sweats
• Muscle pain
• Sensitivity to light (photophobia)
• Severe headaches
• Nausea and diarrhoea
• Cough
• Pain in the chest
• Stomach ache
• Skin rashes that resemble pimples (purpura)
• Dyspnea

About 20% of people who acquire Q fever experience fatigue and other symptoms months or years after their initial exposure. The indications of QFS include:

• Extreme tiredness
• Headaches
• Sweats
• Joint discomfort
• Muscle pain

Even if you didn't exhibit symptoms at the time of your initial C. burnetii infection, chronic Q fever might develop months to years later. Although it frequently affects your heart, heart valves, and blood arteries, the symptoms can change depending on which sections of your body are affected. Signs include:

• Low-grade fever
• Night sweats
• Loss of weight
• Fatigue
• Breathing difficulty
• Swelling of legs or feet⁶

Management and treatment for Q fever

The treatment for those who have Q fever involves antibiotic therapy. Although antibiotic treatments can typically assist in reducing the duration of the infection, some mild cases of Q fever may heal without treatment. Doctors advise that all patients with Q fever should be treated with antibiotics, even if they don't exhibit any symptoms. According to the NHS, doxycycline is currently the most popular antibiotic therapy for treating people with Q fever, and it works best when taken within the first three days after the condition 100 mg is taken once every 12 hours for 14 days. Anti-inflammatory drugs are given to individuals who do not respond to antibiotics.

Hydroxychloroquine, frequently prescribed to treat malaria, is used for treating Q fever. The lysosomal pH can be increased with the assistance of hydroxychloroquine, enabling more efficient antibiotic activity against the bacteria.

Treatment for chronic Q fever is more challenging. Endocarditis may require prolonged antibiotic therapy, which typically requires many medications, including a combination of doxycycline and hydroxychloroquine. Trimethoprim-sulfamethoxazole is an option for people allergic to doxycycline. It is uncertain and varies from person to person how long therapy should last. Surgery can be necessary for those with damaged heart valves or a history of heart failure.

There are no vaccinations that the U.S. Food and Drug Administration continues to approve. Australia has a Q fever vaccine that is 83 to 100% effective at avoiding illness. The vaccination, however, requires that recipients be at least 15 years old. A blood and skin test should be performed prior to vaccination to ascertain whether the individual has previously been exposed to Q fever, either naturally or as a result of prior immunisation.

Management of Q fever symptoms is enhanced by supportive care. It may entail getting a lot of rest and drinking plenty of water. It's crucial to schedule follow-up appointments with a physician to keep track of development and ensure complete recovery.^7,8

Diagnosis of Q fever

Diagnostic methods include:

• Clinical assessment of your medical background, including any contact with animals or situations posing a high risk, will be evaluated by a medical specialist.
• Laboratory tests
• The following test findings may indicate acute Q fever:

• A normal white blood cell (WBC) count (70–90%), mild thrombocytopenia (25%), and increased WBC in as many as 30% are typically seen on a complete blood cell (CBC) test.
• In 70–85% of patients, modest transaminase elevation (2–3 times reference range) and alkaline phosphatase elevation (2–3 times reference range) without hyperbilirubinaemia are typically seen in liver function tests.
• The erythrocyte sedimentation rate (ESR), which typically ranges between 55 and 30 mm/h, is high.
• Numerous positive autoimmune antibodies, such as those against smooth muscle and phospholipid, may be found. 
• Blood cultures are normally negative.
• The subsequent laboratory findings could be seen in patients with chronic Q fever
• Disease-related chronic anaemia

     -   Increased ESR

     -   Elevated polyclonal gamma globulins

     -   Rheumatoid factor (RF) elevation

     -   Elevated creatinine levels

• Immunodetection

Patients receiving treatment for persistent Q fever benefit most from the discovery of C. burnetii in tissues. Samples may be examined unfixed or after being embedded in paraffin and formalin.

• Molecular biology

PCR-based diagnostic methods have become popular using samples and cell cultures.^9,10

Complications of Q fever

Acute and chronic consequences of Q fever could involve:

• Aneurysm
• Arterial fistula
• Endocarditis
• Fibrosis
• Acute respiratory distress syndrome (ARDS)
• Heart attack
• Osteomyelitis
• Loss of pregnancy
• Low weight at birth⁶

Prevention of Q fever

To prevent further disease outbreaks in a region, surveillance of disease, continuous monitoring, and implementation of appropriate preventive and control measures are required. 

Key measures to stop the development of C. burnetii infection include preventive immunisation, waste management such as covering and composting the manure, better livestock farming, and correct disposal and burial of aborted materials. Proper hygiene measures are an essential defence against this infection.

If you work with animals:

Do:

• Wear protective clothing, such as waterproof gloves and goggles.
• Wash your hands frequently. 
• Clean cuts or grazes quickly and cover them with a plaster or dressing.
• Ensure that every animal's placenta is disposed of safely.

Don't:

• Touch anything that may have come into contact with animal blood, faeces, urine, or afterbirth, such as clothing, boots, or gloves, if you're pregnant.
• Ingest unpasteurised (cold-processed) milk.
• Eat in animal-keeping areas.^11,12

FAQs

Is Q fever contagious?

Yes, Q fever is contagious. The bacteria that cause Q fever can infect humans from animals in as few as ten cases. There are very few if any, instances of direct, person-to-person infection.

Who is at risk of Q fever?

• Farmers, ranchers, stockyard workers and livestock truck drivers.
• Attendees at animal auctions.
• Workers in rendering plants and butchers.
• Hunters, meat packers, and trappers who handle hide and wool.
• Animal researchers, zookeepers, veterinary professionals, and support workers.
• Specific health and medical services for those who come into contact with infected people's blood, spit, or tissue.

How common is Q fever?

The likelihood of contracting Q fever varies by location and happens more commonly in rural areas with lots of livestock.

When should I see a doctor?

You should see a doctor if you have a high fever, intense headache, aching muscles, tiredness, or respiratory symptoms and think you may have Q fever.

Summary

It's relatively rare to suffer from Q fever. If you think you may have been exposed to Q fever or have unpleasant symptoms, consult a doctor as soon as possible. They can better assess your risks and provide the most effective treatments if you let them know about your medical background and employment history.

References

1. Q Fever - Infectious Disease and Antimicrobial Agents [Internet]. Infectious Disease and Antimicrobial Agents. [cited 2023 May 28]. Available from: http://www.antimicrobe.org/r08.asp

2. CDC. Q fever epidemiology and statistics | CDC [Internet]. Centers for Disease Control and Prevention. 2021 [cited 2023 May 28]. Available from: https://www.cdc.gov/qfever/stats/index.html

3. Q Fever - PMC [Internet]. PubMed Central (PMC). [cited 2023 May 28]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC88923/

4. Q Fever [Internet]. BC Centre for Disease Control. [cited 2023 May 29]. Available from: http://www.bccdc.ca/health-info/diseases-conditions/q-fever

5. Q fever treatment, causes, diagnosis & vaccine [Internet]. MedicineNet. [cited 2023 May 29]. Available from: https://www.medicinenet.com/q_fever/article.htm

6. Q fever: causes, symptoms, diagnosis, prevention & treatment [Internet]. Cleveland Clinic. [cited 2023 May 29]. Available from: https://my.clevelandclinic.org/health/diseases/17883-q-fever

7. Q fever - symptoms, causes, treatment | nord [Internet]. [cited 2023 May 30]. Available from: https://rarediseases.org/rare-diseases/q-fever/

8. Q fever - including symptoms, treatment and prevention | SA Health [Internet]. Home | SA Health. [cited 2023 May 30]. Available from: https://www.sahealth.sa.gov.au/wps/wcm/connect/public+content/sa+health+internet/conditions/infectious+diseases/q+fever/q+fever+including+symptoms+treatment+and+prevention

9. Q fever: practice essentials, background, pathophysiology. 2023 Feb 1 [cited 2023 May 30]; Available from: https://emedicine.medscape.com/article/227156-overview?reg=1

10. Emmanouil Angelakis, Didier Raoult. Q fever. Veterinary Microbiology, 2010, 140 (3-4), pp.297. ff10.1016/j.vetmic.2009.07.016ff. Ffhal-00556051f [cited 2023 Jun 1]. Available from: https://hal.science/hal-00556051/document

11. Q fever | nidirect [Internet]. 2018 [cited 2023 Jun 1]. Available from: https://www.nidirect.gov.uk/conditions/q-fever

Ullah Q, Jamil T, Saqib M, Iqbal M, Neubauer H. Q fever—a neglected zoonosis. Microorganisms [Internet]. 2022 Aug [cited 2023 Jun 1];10(8):1530. Available from: https://www.mdpi.com/2076-2607/10/8/1530