Generality
Q fever is an uncommon infectious disease, transmitted by animals (in particular from breeding ones) and caused by a bacterium called Coxiella Burnetii .
Figure: Coxiella Burnetii, causal agent of Q fever
In most cases, the disease resembles a normal flu; more rarely, Q fever can give rise to serious complications and / or assume the contours of a chronic disease. In the latter case, the most serious damage can appear at the level of the heart.
The diagnosis is quite simple and is based on a quick blood test.
The milder forms of Q fever heal within a couple of weeks and without any special treatment. The more severe forms, on the other hand, may require prolonged antibiotic-based treatments.
What is Q fever?
Q fever is a human infectious disease caused by Coxiella Burnetii, a bacterium widespread in many animal species, particularly sheep, goats and farmed cattle.
Those affected show symptoms that recall the symptoms of influenza, therefore: fever, muscle pain and headache.
Some features of Coxiella Burnetii . It is a Gram-negative bacterium, resistant to high temperatures and ultraviolet light. According to biologists, if the external environment is favorable it can survive even 6 months without infecting anyone.
HISTORY
Q fever was first described in 1935. It was done by a pathologist, Edward H. Derrick, who found the infection among some workers in an Australian slaughterhouse. Since he did not understand the causes, Derrick decided to identify it with the letter Q of "query", the English term meaning "question mark".
Two years later, in 1937, Frank M. Burnet and Mavis Freeman isolated the responsible bacterium, namely Coxiella Burnetii ; while, in 1938, Herald R. Cox and Gordon Davis clarified the transmission mechanism.
The name Coxiella Burtetii was given in honor of HR Cox and FM Burnet.
Epidemiology
Q fever is widespread throughout most of the world, but it is not very common. In England, for example, it affects around 50 people a year, although it must be stressed that it is often confused by a normal influence (so it is underdiagnosed).
The people most affected are those who often come into contact with animals from livestock, such as peasants, veterinarians, breeders, animal transporters, slaughterhouse employees etc.
Causes
The infectious agent of Q fever, Coxiella Burnetii, is a common bacterium in many animals of different species, such as goats, sheep, breeding cattle, dogs, cats, Guinea pigs and rabbits.
These animals can be a source of infection if the man comes into contact with their urine, their faeces, their milk, their blood or placenta and amniotic fluid residues resulting from the conception of their young.
HOW DOES THE INFECTED-MAN ANIMAL TRANSMISSION TAKE PLACE?
The passage of the bacterium from the infected animal to humans can take place by:
- Inhalation of small particles released by the animals when they are slaughtered or when they give birth.
- Inhalation of contaminated dust from straw, hay and the land where animals usually reside.
- Penetration through some cuts and wounds on the hands, after touching urine, faeces or body fluids of contaminated animals.
- Penetration of dust and contaminated particles into the eyes
- Having drunk unpasteurized milk, produced from contaminated animals.
It seems that ticks infect animals. These could directly cause the disease also in humans, but based on several studies this happens very rarely.
INTERUMAN TRANSMISSION
Although this is a very remote possibility, it is possible for an individual with Q fever to transmit the bacterium responsible for the disease to another person. According to experts, transmission between humans can occur in two circumstances:
- After a sexual relationship between a sick person and a healthy one.
- In case of pregnancy, with the passage of the infection from the mother to the child.
FEBRUARY Q IS A ZOONOSIS
Q fever belongs to the class of zoonoses, or infectious diseases that are transmitted from animals to humans. Unless they adapt to the human species, zoonoses cause problems only to the individual who contracts them.
Factors that increase the risk of getting Q fever
- Work involving continuous contact with potentially contaminated animals.
- Living near farms, farms and mornings, because the particles can get carried away by the air and make long journeys.
- Male sex, because risky jobs are usually done by men.
Symptoms and Complications
Q fever can be asymptomatic, that is, free of obvious pathological signs, or characterized by disorders similar to flu symptoms .
Going into more detail, the infection is able to cause:
- High fever, even at 41 ° C
- Strong headache
- Muscle and joint pain
- Intense sweating
- Cough and sore throat
- Photophobia (light sensitivity)
- Weight loss
- Nausea
- Diarrhea
- Skin erythema
These manifestations can appear both a few days after infection and several weeks later (30-40 days). Their duration generally does not exceed two weeks.
A SPECIAL CASE OF FEBRUARY Q: THE FEBRUARY Q CHRONIC
In some cases, Q fever can take on the characteristics of a very serious chronic disease (called precisely chronic Q fever ); in similar circumstances, it can cause a very prolonged symptomatology (sometimes even more than 6 months) and the appearance of a serious cardiac disorder known as endocarditis .
Endocarditis is an inflammatory process affecting the membranes that line the internal cavities of the heart and the four heart valves.
Deepening: what is the cause of chronic Q fever?
According to some scientific investigations, chronic Q fever is more likely to arise if:
- You suffer from particular cardiac disorders (coronary heart disease, congenital heart defects and valvulopathies)
- He underwent heart surgery
- You suffer from kidney problems of a certain size
- You are sick with some form of lymphoma or leukemia
COMPLICATIONS
In some individuals, Q fever also develops pneumonia and / or hepatitis.
Pneumonia is inflammation of the lungs, hepatitis is inflammation of the liver. The first must be followed carefully and treated promptly, because it could cause serious consequences such as the so-called acute respiratory distress syndrome ( ARDS ); the second, on the other hand, is generally mild and gives rise to hepatomegaly (ie enlargement of the liver) and abdominal pain.
PREGNANCY
In some cases, Q fever contracted during pregnancy could lead to various complications, such as: premature birth, spontaneous abortion and low birth weight .
Diagnosis
To diagnose Q fever, a blood sample must be taken from the suspect individual and their antibody content analyzed (ie the type of antibodies present). If there are antibodies against the bacterium Coxiella Burnetii in the blood sample, it means that the patient under test has Q fever.
In particular cases of chronic Q fever, more in-depth diagnostic tests must be performed, such as chest x-ray and echocardiogram, in order to examine the health conditions of the heart.
Warning: in blood, antibodies appear only 2 or 3 weeks after infection.
Treatment
Mild or asymptomatic forms of Q fever usually heal within two weeks, without resorting to particular treatments.
On the other hand, moderate to severe forms and chronic Q fever require antibiotic treatment.
If heart damage occurs (in particular one of the four heart valves), heart surgery may also be necessary.
IN CASE OF FEVER Q MODERATE / SERIOUS, WHAT ANTIBIOTICS MUST BE TAKEN AND FOR HOW LONG?
The most widely used antibiotics are doxycycline, tetracycline, chloramphenicol, ciprofloxacin and hydroxychloroquine .
Once the type of antibiotic drug has been chosen, it should be taken for about 14 consecutive days and at least three times a day. It is important to give continuity to the treatment and to be regular in the administrations, because this is the only way to heal better and in the shortest possible time.
FEBRUARY Q CHRONIC
In the case of chronic Q fever, a combination of antibiotics is used : usually doxycycline and quinolones or doxycycline and hydroxychloroquine are administered.
To be sure of eliminating the bacterium Coxiella Burnetii from the body and to avoid relapses, taking the prescribed medicines should last at least 18 months.
During the entire period of therapy, every 3-6 months, blood tests are scheduled, the purpose of which is to assess the state of the infection and the benefits of treatment.
Once healing has been completed, it is advisable to undergo a complete heart check and a thorough blood test at least once a year for several years. This is a completely precautionary measure, aimed at promptly identifying any relapses or complications of the heart.
NB: quinolones are synthetic antibiotics.
Prevention
- For those who can develop chronic Q fever . Individuals predisposed to the chronic form of Q fever (ie heart patients, leukemia sufferers, those suffering from some kind of kidney disease, etc.) should avoid carrying out jobs and activities considered at risk, such as working in a farm. of cattle.
- For healthy people . Healthy people who live in close contact with potentially infected animals should avoid drinking unpasteurized milk and products derived from it. In addition, they should protect themselves from inhalation and contact with contaminated dust and particles.
- For pregnant women . A pregnant woman, who usually lives in close contact with animals potentially contaminated by the bacterium Coxiella Burnetii, must refrain from any work considered at risk.
NB: in some countries of the world, such as the United States and Australia, there is the possibility of vaccinating, even if, in general, this practice is reserved exclusively for people who carry out work considered at risk of Q fever.
