What is Brucellosis?

Brucellosis is an infectious disease that is caused by bacteria known as Brucella species. It’s also known by many other names such as Mediterranean fever, Maltese fever, Gibraltar fever, Crimean fever, goat fever, and Bang disease, among others. The disease was first identified in 1751 by British army surgeon, George Cleghorn and later studied more intensively after the Crimean War on the island of Malta. The name of the bacteria, Brucella, got its name from Major-General Sir David Bruce who identified the bacteria as the cause of this disease in 1886. It was later revealed in 1905 by Sir Themistocles Zammit that infected goats could spread brucellosis through their milk.

The Brucella bacteria are tiny organisms that usually live inside host animals’ reproductive organs, causing issues like abortions and sterility in these animals. These bacteria can be shed in urine, milk, and other body fluids of the animals. The bacteria come in various species, but the ones that are harmful to humans include: Brucella melitensis (from sheep), Brucella suis (from pigs), Brucella abortus (from cattle), and Brucella canis (from dogs). Among these, Brucella melitensis and Brucella suis are the most harmful, while Brucella abortus and Brucella canis have moderate harmfulness.

What Causes Brucellosis?

Brucellosis is an infection that’s passed from animals to humans which can be caused by four different types of Brucella bacteria: B. suis, B. melitensis, B. abortus, and B. canis. Even a few (10 to 100) of these bacteria can make a person sick. All of these bacteria types don’t move, live inside cells, and are neither spore-forming nor toxin-producing. Swine carry B. suis, sheep and goats carry B. melitensis, cattle carry B. abortus, and dogs carry B. canis.

Out of these, B. melitensis is the most potent and most prevalent globally, causing the most serious cases of brucellosis. People commonly get B. melitensis from interacting with infected animals or their products, largely through eating unpasteurized goat milk and related dairy foods. Workers in slaughterhouses can get infected when they come into contact with the bacteria present in body fluids and tissues of animals that becomes airborne. Similarly, veterinarians are often infected when administering animal vaccines against B. abortus and B. melitensis. Lab workers may get infected when handling tissues of infected specimens for testing or experiments.

While B. abortus is more common and less harmful to both animals and humans, it has been the leading cause of brucellosis in North America, seldom leading to complications. B. suis, the second most common cause of brucellosis in North America, typically results in long-term illness tied to destructive pus-producing lesions. B. canis, carried by dogs, leads to a disease akin to that caused by B. abortus.

Risk Factors and Frequency for Brucellosis

Brucellosis is a disease that typically spreads from animals to humans through the consumption of unpasteurized milk, dairy products, undercooked meat, or through direct contact with livestock. Inhalation of contaminated aerosols and blood transfusions can also lead to its transmission. The virus can pass from mother to fetus, and in rare cases, from person to person.

  • Brucellosis is notably common amongst workers in an animal-related profession due to occupational exposure.
  • The disease causes over 500,000 infections globally each year, although the numbers have decreased significantly in the United States as a result of animal vaccination programs and pasteurization of milk.
  • In 2010, the US reported 115 cases of brucellosis, the majority of which were in California and Texas.

The disease is especially common among young people. Around 60% of reported cases are in people between 13 to 40 years old, 16% are in people between 40 to 60 years old, while only 2.5% are in people older than 60 years old. Children in developing countries where pasteurization is not common may also have higher rates of brucellosis.

As for gender, brucellosis is more prevalent in males than females, likely due to men having more occupational exposure to animals.

Signs and Symptoms of Brucellosis

Brucellosis is a disease which can be diagnosed through a detailed history, particularly a dietary history. This is because the disease can be contracted by eating infected food shipped from areas where the disease is common. It’s particularly important to consider this if the patient lives in a region where brucellosis isn’t usually found.

The symptoms of brucellosis can include:

  • Headache
  • Periodic fever
  • Pain in different joints
  • Muscle pain
  • Feeling of tiredness or weakness
  • Lack of appetite
  • Sweating
  • Vomiting
  • Diarrhea
  • Abdominal pain
  • Possible miscarriage

Sometimes, the disease can result in conditions like sacroiliitis, osteomyelitis, spondylodiscitis, septic arthritis, and epidural abscess. Symptoms relating to the respiratory system, such as cough and shortness of breath, can also occur. Some patients might develop neurological symptoms, skin and ocular issues. One interesting symptom reported in some cases is a strong, unpleasant body odor, reminiscent of mold or wet hay.

During a physical examination, doctors often find that patients’ spleen or liver may be enlarged. There may also be swollen lymph nodes. In men, inflammation of the testes and associated structures could occur. Heart-related issues like endocarditis and pericarditis may also be present. Rarely, aortic fistulas can occur. The patient may present various neurological signs depending on their specific condition – these can range from papilledema, cranial nerve palsy, focal neurological deficits to symptoms like maculopapular eruptions, erythema nodosum, abscesses, and panniculitis on the skin, and even eye issues like uveitis, keratoconjunctivitis, iridocyclitis, optic neuritis, and cataracts.

Gram stain showing brucella, a gram-negative bacteria. They are small single
cells that are poorly stained.
Gram stain showing brucella, a gram-negative bacteria. They are small single
cells that are poorly stained.

Testing for Brucellosis

If you have brucellosis, the symptoms may not be very specific, which is why lab tests are typically needed for a correct diagnosis. Here is what might be done:

Full Blood Test:

In conditions like brucellosis, a complete blood count might be done. This could reveal lower than normal levels of white blood cells, red blood cells, or platelets (the substances that help with clotting). Some patients may have all three of these levels lower than normal, which is referred to as pancytopenia.

Inflammation Tests:

Your doctor might also test for inflammation in your body by checking the levels of markers such as C-reactive protein, erythrocyte sedimentation rate, serum lactate dehydrogenase, and alkaline phosphatase. Increased levels of these markers can suggest an ongoing inflammation in the body.

Liver Tests:

Liver tests can show whether your liver enzymes are at higher than normal levels, which happens quite often in brucellosis. If your liver is severely affected by the disease, you might also have an enlarged liver (hepatomegaly).

Cultures:

Because brucellosis is caused by bacteria, cultured samples of your blood or bone marrow might show the presence of the bacteria – although this may take more than a week due to the slow growth of brucellosis bacteria. Bone marrow cultures are usually more reliable owing to the higher concentration of bacteria in the marrow compared to the blood.

Antibody Tests:

If you live in an area where brucellosis is common, you might be subject to a standard agglutination test – a routine test to look for the brucella bacteria. Two other tests – an indirect enzyme-linked immunosorbent assay (ELISA) and Rose Bengal testing – are also available. In these tests, higher than normal antibody levels suggest an infection.

DNA Detection:

Brucella bacteria DNA can be detected in human blood samples through a method known as Polymerase chain reaction (PCR).

Radiography:

X-rays and other imaging techniques may show signs of damage to your backbone or spine as a result of brucellosis. This may be seen as an erosion of one or more vertebrae (backbones) or a narrowing of the disc spaces between these. In severe cases of the disease, images may show deformities or destruction of the bones.

Biopsy:

In certain cases, a biopsy may be needed to confirm the diagnosis of brucellosis. Samples of your bone marrow or liver are often taken for this test, through soft, long needles inserted into the corresponding areas. Biopsy analysis may show hepatitis or hepatic microabscesses in the liver.

Treatment Options for Brucellosis

The goal of treating brucellosis, a bacterial infection, is to manage the disease quickly to prevent further complications and recurrence.

Various Antibiotics

To treat brucellosis, doxycycline is commonly used together with another antibiotic like streptomycin, rifampin, gentamicin, or sulfamethoxazole/trimethoprim. Since the bacteria causing brucellosis live inside cells, the treatment needs to last several weeks. Using just a single antibiotic is typically avoided, as it often leads to the disease recurring. For uncomplicated cases, doxycycline alone could be the best option; however, it’s often combined with rifampin because the disease has a high chance of recurring with doxycycline monotherapy.

In the case of children who should not take doxycycline, a combination of trimethoprim-sulfamethoxazole and rifampin is often used for 4 to 6 weeks. Pregnant women can be treated with rifampin during pregnancy, adding trimethoprim-sulfamethoxazole after giving birth. If the disease affects the spine or sacroiliac joints, the typical treatment plan includes doxycycline and rifampin together with an aminoglycoside antibiotic like gentamicin for the first 2-3 weeks, followed by 6 weeks of rifampin and doxycycline.

Other Medications

Other drugs to manage the symptoms, including fever reducers and pain relievers, must also be given. Steroids can also be used in patients with brucella meningitis, although there’s a lack of evidence about their effectiveness.

The Role of Surgery

Surgery may be necessary in brucellosis patients for treating heart inflammation or draining joint effusions or abscesses along the spine. Infected heart valves might need replacement, and repair for aortic and aortopulmonary fistulas can also be done. In some instances, surgical cleaning and bone grafting might be performed on patients with spinal infections. In the US, dairy herds are tested yearly for brucellosis, vaccinating cows against the disease since accidental exposure to the cow vaccine has been shown to cause the disease in humans.

Brucellosis is a disease that can seem like many other sicknesses caused by bacteria and viruses. When doctors suspect a patient has brucellosis, here are some other conditions they should consider as possibilities:

  • Epstein bar virus, which causes mononucleosis, a condition often called ‘mono’
  • Infective endocarditis, an infection of the inner lining of the heart
  • Influenza, more commonly known as the flu
  • Leptospirosis, a bacterial infection that can cause a wide range of symptoms
  • Malaria, a serious disease usually spread through mosquito bites
  • Mechanical back pain, usually caused by bad posture, improper lifting or a physical injury
  • Meningitis, an illness that causes inflammation in the brain and spinal cord
  • Mycoplasma pneumonia, often referred to as ‘walking pneumonia’
  • Viral hepatitis, a condition where the liver becomes inflamed due to a viral infection
  • Enteric fever, a high fever caused by certain types of bacteria
  • Acute epididymitis, an inflammation of the epididymis, a tube located at the back of the testicles
  • Urinary tract infection, commonly known as a UTI

These diseases can present similar symptoms to brucellosis, making them important to consider in ensuring an accurate diagnosis.

What to expect with Brucellosis

For most patients with brucellosis, the outlook is very positive, although it may take a while to manage the symptoms. The chance of the disease returning is quite low. However, for patients who have other health conditions such as heart or lung diseases, brucellosis can become debilitating. Especially difficult cases are those people who experience heart failure due to endocarditis – their outlook isn’t good.

Interestingly, unlike most infections, brucellosis tends to improve with physical activity instead of bed rest. Recovery typically takes between three to six months. If the disease comes back, it either affects a specific area (local) or the entire body (systemic). But overall, the death rate for acute or chronic brucellosis is really low, definitely under 5% and likely even under 2%.

Possible Complications When Diagnosed with Brucellosis

If a patient is treated promptly and correctly, complications from brucellosis are unusual, but there may be a recurrence of the infection. If symptoms have been present for more than a month before diagnosis, there is a higher chance of developing additional complications. Here are the most common complications of brucellosis:

  • Cardiovascular complications, including
    • Endocarditis (infection of the heart’s inner lining)
    • Myocarditis (inflammation of the heart muscle)
    • Pericarditis (inflammation of the sac-like covering around the heart)
    • Mycotic aneurysms (abnormal widening of blood vessels) of the aorta and cerebral vessels
  • Problems with the reproductive and excretory systems, including
    • Orchitis (inflammation of the testicles)
    • Epididymo-orchitis (inflammation of the testicles and epididymis)
    • Glomerulonephritis (a type of kidney disease)
    • Pyelonephritis (kidney infection)
    • Abortion (in pregnant women)
  • Central nervous system complications, such as
    • Meningitis (inflammation of the membranes around the brain and spinal cord)
    • Meningoencephalitis (inflammation of the brain and its surrounding membranes)
    • Papilledema (swelling of the optic disc)
    • Radiculopathy (nerve condition that causes pain, numbness or weakness)
    • Stroke
    • Optic neuropathy (damage to optic nerves)
  • Blood-related complications, such as
    • Disseminated intravascular coagulation (blood clots and bleeding disorder)
    • Hemophagocytic syndrome (overactive immune response)
  • Musculoskeletal complications, like
    • Spondylitis (inflammation of the spine)
    • Sacroiliitis (inflammation of the sacroiliac joints)
    • Arthritis
    • Osteomyelitis (bone infection)
    • Bursitis (inflammation of the bursae, small sacs of synovial fluid)
    • Tenosynovitis (tendon sheath inflammation)
  • Gastrointestinal or hepatobiliary complications, such as
    • Hepatitis (inflammation of the liver)
    • Hepatic abscess (abscess in the liver)
    • Acute cholecystitis (gallbladder inflammation)
    • Ileitis (inflammation of the ileum)
    • Colitis (inflammation of the colon)
    • Spontaneous peritonitis (inflammation of the peritoneum, the tissue lining the abdomen)
  • Abscesses (pockets of pus) in the spinal cord, spleen, or thyroid

Recovery from Brucellosis

Most patients can receive care without being hospitalized, unless there are complications. Staying away from whatever caused the infection is crucial. In order to check if the treatment is working, blood tests are necessary. Following the medical treatment correctly is key to recovering completely.

Preventing Brucellosis

Patients should be given information about the disease: what it is, how it spreads, what symptoms it can cause, the possible complications, and the treatments available. They also need to be aware of several key points:

– Understanding the potential side effects of the medications
– Stick to the medication regimen until they are fully healed
– Stay away from animals that might be infected and use gloves and masks when handling an infected animal. Also, try to avoid food that could be contaminated
– Make sure that cattle, sheep, and goats are vaccinated
– Properly cook meat and make sure dairy products are pasteurized
– Lab workers need to make sure they are taking the right safety measures to prevent contamination.

Frequently asked questions

Brucellosis is an infectious disease caused by bacteria known as Brucella species. It can be transmitted to humans through the urine, milk, and other body fluids of infected animals, causing issues like abortions and sterility in these animals.

The disease causes over 500,000 infections globally each year, although the numbers have decreased significantly in the United States as a result of animal vaccination programs and pasteurization of milk.

The signs and symptoms of Brucellosis include: - Headache - Periodic fever - Pain in different joints - Muscle pain - Feeling of tiredness or weakness - Lack of appetite - Sweating - Vomiting - Diarrhea - Abdominal pain - Possible miscarriage In addition to these symptoms, Brucellosis can also result in other conditions such as sacroiliitis, osteomyelitis, spondylodiscitis, septic arthritis, and epidural abscess. Respiratory symptoms like cough and shortness of breath can occur, and some patients may develop neurological symptoms, skin issues, and ocular problems. Another interesting symptom reported in some cases is a strong, unpleasant body odor resembling mold or wet hay. During a physical examination, doctors may find an enlarged spleen or liver, swollen lymph nodes, and inflammation of the testes and associated structures in men. Heart-related issues like endocarditis and pericarditis may also be present, and in rare cases, aortic fistulas can occur. Neurological signs can vary depending on the specific condition and may include papilledema, cranial nerve palsy, focal neurological deficits, and skin manifestations such as maculopapular eruptions, erythema nodosum, abscesses, and panniculitis. Eye issues like uveitis, keratoconjunctivitis, iridocyclitis, optic neuritis, and cataracts can also occur in some cases.

Brucellosis can be contracted through the consumption of unpasteurized milk, dairy products, undercooked meat, or through direct contact with livestock. It can also be transmitted through inhalation of contaminated aerosols, blood transfusions, and from mother to fetus. In rare cases, it can be transmitted from person to person.

The doctor needs to rule out the following conditions when diagnosing Brucellosis: - Epstein bar virus, which causes mononucleosis, a condition often called 'mono' - Infective endocarditis, an infection of the inner lining of the heart - Influenza, more commonly known as the flu - Leptospirosis, a bacterial infection that can cause a wide range of symptoms - Malaria, a serious disease usually spread through mosquito bites - Mechanical back pain, usually caused by bad posture, improper lifting or a physical injury - Meningitis, an illness that causes inflammation in the brain and spinal cord - Mycoplasma pneumonia, often referred to as 'walking pneumonia' - Viral hepatitis, a condition where the liver becomes inflamed due to a viral infection - Enteric fever, a high fever caused by certain types of bacteria - Acute epididymitis, an inflammation of the epididymis, a tube located at the back of the testicles - Urinary tract infection, commonly known as a UTI

The types of tests that are needed for Brucellosis include: 1. Full Blood Test: This includes a complete blood count to check for lower than normal levels of white blood cells, red blood cells, or platelets. 2. Inflammation Tests: These tests check for markers of inflammation in the body, such as C-reactive protein, erythrocyte sedimentation rate, serum lactate dehydrogenase, and alkaline phosphatase. 3. Liver Tests: These tests check for higher than normal levels of liver enzymes and may also show an enlarged liver. 4. Cultures: Cultured samples of blood or bone marrow can be tested to detect the presence of the Brucella bacteria. 5. Antibody Tests: Standard agglutination tests, indirect enzyme-linked immunosorbent assays (ELISA), and Rose Bengal testing can be used to look for higher than normal levels of antibodies, indicating an infection. 6. DNA Detection: Polymerase chain reaction (PCR) can be used to detect Brucella bacteria DNA in blood samples. 7. Radiography: X-rays and other imaging techniques can show signs of damage to the backbone or spine. 8. Biopsy: In some cases, a biopsy of the bone marrow or liver may be needed to confirm the diagnosis of Brucellosis. These tests are important for a proper diagnosis of Brucellosis and to determine the appropriate treatment plan.

Brucellosis is typically treated with a combination of antibiotics, such as doxycycline and rifampin, to manage the disease quickly and prevent further complications and recurrence. The treatment needs to last several weeks because the bacteria causing brucellosis live inside cells. For children who cannot take doxycycline, a combination of trimethoprim-sulfamethoxazole and rifampin is often used. Pregnant women can be treated with rifampin during pregnancy, adding trimethoprim-sulfamethoxazole after giving birth. In some cases, surgery may be necessary to treat complications such as heart inflammation or draining joint effusions or abscesses. Other medications, such as fever reducers and pain relievers, may also be given to manage symptoms.

When treating Brucellosis, there can be side effects from the medications and complications of the disease itself. Some of the side effects and complications include: - Side effects of antibiotics: The antibiotics used to treat Brucellosis can have side effects such as nausea, vomiting, diarrhea, and allergic reactions. - Complications of Brucellosis: If the disease is not managed quickly or if there is a delay in diagnosis, there can be various complications, including: - Cardiovascular complications: Endocarditis, myocarditis, pericarditis, and mycotic aneurysms. - Reproductive and excretory system complications: Orchitis, epididymo-orchitis, glomerulonephritis, pyelonephritis, and abortion in pregnant women. - Central nervous system complications: Meningitis, meningoencephalitis, papilledema, radiculopathy, stroke, and optic neuropathy. - Blood-related complications: Disseminated intravascular coagulation and hemophagocytic syndrome. - Musculoskeletal complications: Spondylitis, sacroiliitis, arthritis, osteomyelitis, bursitis, and tenosynovitis. - Gastrointestinal or hepatobiliary complications: Hepatitis, hepatic abscess, acute cholecystitis, ileitis, colitis, and spontaneous peritonitis. - Abscesses: Pockets of pus in the spinal cord, spleen, or thyroid.

For most patients with brucellosis, the outlook is very positive, although it may take a while to manage the symptoms. The chance of the disease returning is quite low. However, for patients who have other health conditions such as heart or lung diseases, brucellosis can become debilitating. Especially difficult cases are those people who experience heart failure due to endocarditis - their outlook isn't good. Recovery typically takes between three to six months. If the disease comes back, it either affects a specific area (local) or the entire body (systemic). But overall, the death rate for acute or chronic brucellosis is really low, definitely under 5% and likely even under 2%.

You should see an infectious disease specialist for Brucellosis.

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