Humans are certainly not the only creature to be living on earth. The existence of certain animals in a human life can be either as food or a pet. There are reasons why there are ways of taking care of animals or when handling one as it does have an effect on humans. Some animals may actually be the root cause for disease in humans. In this DoctorOnCall’s article, we will learn more about Q fever in humans.
The bacterium Coxiella burnetii is the source of Q fever..This bacteria naturally infects some animals such as goats, cattle and sheep. This bacteria is found in the birth product (placenta, amniotic fluid), urine, faeces and milk of infected animals. The way humans are infected by this bacteria is through inhaling dust contaminated by infected animal faeces, urine, milk and birth products. Humans may also get sick with Q fever by eating contaminated, unpasteurized dairy products. It is rare for Q fever to be spread through blood transfusion, sexual intercourse or from pregnant mother to her baby.
There are groups of people that are at risk for exposure to Coxiella burnetii that include veterinarians, researchers at facilities housing sheep or goats, dairy workers, livestock farmers, and meat processing plant workers. Q fever can occur at any time of the year with most cases in the spring and early summer months. These are the birthing seasons for cattle, sheep and goats.
Symptoms of Q fever can vary from one person to another. Infection can result in no apparent symptoms or also known as asymptomatic, acute form which is often presented as flu-like illness which goes away on its own or serious symptoms which are associated with chronic form. Below are symptoms based on duration:
- Acute Q fever- starts approximately 2 to 3 weeks after exposure to the bacteria. Symptoms of acute Q fever include high fever, fatigue, headaches, muscle pain (myalgia), chills and muscle weakness. Dry cough and chest pain may appear, particularly in older or debilitated patients. Hepatitis may occur.
- Acute Q fever may not have preceded chronic Q fever, or it may emerge months to years following acute illness. Most cases are individuals with underlying conditions such as existing heart or blood vessel abnormalities or immunocompromised persons. Only a small percentage have chronic Q fever. Symptoms include night sweats, fatigue, shortness of breath, weight loss and swelling of the limbs. Liver problems such as hepatitis and hepatomegaly can occur. In less common cases, patients may have bone or joint pain due to infection of the bones and joints.
Diagnosing Q fever can be difficult as its symptoms may be similar to other diseases. Those who have symptoms associated with Q fever after spending time with or near animals, especially sheep, goats and cattle, need to get checked by doctors. Doctors will order blood tests to check for infection signs. Imaging tests may be done in certain cases with the possibility of using echocardiograms to evaluate the heart and its function. Diagnosis is typically confirmed with a serologic test or PCR.
Most people who are sick with Q fever do recover without antibiotic treatment. However, it is recommended that those who develop Q fever disease get treatment. Treatment is based on how serious the illness is. For acute Q fever, antibiotics such as doxycycline are prescribed by doctors. Antibiotics courses are usually 2 weeks. For chronic Q fever, patients often require several months of antibiotic treatment. Combinations of antibiotics such as doxycycline and hydroxychloroquine are given for several months.
The best way to prevent Q fever is to get vaccination. This vaccination is recommended to those at high risk for the infection such as those working with animals. Skin tests and blood tests are done before vaccination to check for previous exposure to Q fever. Those who have recovered from Q fever may have had lifelong immunity against the disease. However, since vaccines may not be feasible in all countries, there are other precautions that can be taken to avoid developing Q fever. This includes avoiding contact with animals especially when the animals are giving birth, practising good hygiene practices in premises, and avoiding consuming raw milk or raw milk products. Those who have been diagnosed with Q fever and have a history of heart abnormalities or with weak immune systems, should discuss with their healthcare provider on how to lower the risk for developing chronic Q fever.
In essence, Q fever is an infection caused by Coxiella burnetii bacteria. This bacteria can be found in many animals but most common is cattle, sheep and goat. Humans can get infected by the bacteria through inhaling dust or consuming food contaminated by the birth products, urine, faeces or urine of an infected animal. Treatment emphasises on prescription of antibiotics depending on severity of the disease.