Parvoviruses

What is Parvoviruses?

Parvovirus B19 is a type of virus that doesn’t have an outer shell and has a unique design similar to a twenty-sided shape. It carries a single strand of DNA. The virus can only infect humans and is known for causing a condition commonly known as fifth disease, or ‘slapped cheek syndrome’. It’s often seen in young children, but adults can get it too. It can also cause a condition called aplastic crisis in people with certain types of anemia, a condition called hydrops fetalis in pregnant women, joint problems, and a skin condition that’s often seen in young adults called papular-purpuric gloves and socks syndrome, or PPGSS. The virus can be passed between people through respiratory secretions, like sneezing or coughing, and blood products. If a woman becomes pregnant and gets infected with the virus, it can be passed to her baby.

What Causes Parvoviruses?

Parvovirus B19 is a virus that is uniquely shaped and does not have an outer layer. It carries a single-strand, linear DNA. Interestingly, this virus only affects humans, which means you cannot get it from animals.

Risk Factors and Frequency for Parvoviruses

Parvovirus B19 is a common infection that is found all over the world, primarily affecting school-aged children. However, it can affect people of all ages. The time when it most typically spreads is in the late winter, spring, and early summer. It’s also noted that mini-outbreaks happen roughly every three to four years.

• In developed countries, 2% to 10% of children under the age of 5 are affected by Parvovirus B19.
• For adults over the age of 20, the prevalence increases to between 40% and 60%.
• People who are 70 years and older have the highest prevalence, with 85% or more having had the infection.

Signs and Symptoms of Parvoviruses

Erythema Infectiosum is a condition characterized by a distinct set of symptoms. This usually begins with a headache, muscle pain, and fever due to a viral infection. After about one to one and a half weeks, the patient develops a rash. An important point to remember is that the individual is non-transmissible once the rash appears. An easily recognized “red-cheeked” look occurs where the central face is typically untouched. However, adults may not display this particular rash. A ‘lacy’ looking rash, particularly on the arms and legs, but also lightly on the torso, will then appear. This rash, lasting from one to three weeks, may intensify when exposed to heat or sunlight. Small joint arthritis might develop, particularly affecting the hands, feet, and knees. This is more common in adults, particularly women, and is rather rare in children.

In some cases, arthritis can occur without any visible skin changes, usually persists for one to three weeks. People already dealing with conditions that lead to a decrease in red blood cells production or an increase in their destruction may experience a crisis state. This circumstance is particularly true for patients with iron deficiencies, thalassemias, or diseases like sickle-cell anemia, and those who have undergone stem cell or solid organ transplants.

During pregnancy, the parvovirus B19 has the chance of being transmitted from the mother to the fetus. This is usually the case in situations where the pregnancy is below 20 weeks. The virus, by blocking fetal red blood cell production, can lead to profound anemia, stillbirth, fetal death, or hydrops (which is the abnormal accumulation of fluid in various fetal compartments). The majority of such cases happen in the second trimester despite the overall risk being low, around 2% to 6%. Testing for this virus is typically not done during preconception or prenatal screenings.

• Headache
• Muscle pain
• Fever
• Rash with a red cheeked appearance
• Arthritis
• Crises due to underlying red blood cell dysregulation disorders or transplant procedures
• Possible fetal complications if the mother contracts the disease during pregnancy

A related condition, Papular Purpuric Gloves and Socks Syndrome affects mostly young adults, but could happen at any age. Characterized by small blue or purple spots and a clear boundary at the wrists and ankles. It also includes symptoms like swelling and redness of the palms and soles, burning or itching sensation, and might also affect areas where skin touches skin. Unlike Erythema Infectiosum, patients are contagious when they have this rash. Mouth-related symptoms like erosion and small reddish spots might also occur, affecting the palate, throat, and tongue.

Testing for Parvoviruses

The best way to test for an infection is by examining certain proteins in the blood called “serum anti-B19 IgM antibodies”. If this test comes back positive, it suggests that you’ve been infected within the last two to four months. Another protein, “IgG antibody”, will usually show up in tests after one week of an infection. One more option is to run a PCR test which checks for the presence of the virus in your blood or tissue samples.

Treatment Options for Parvoviruses

The treatment for a condition known as erythema infectiosum, mostly seen in children, is usually focused on relieving the symptoms rather than treating the root cause. This is because children with this condition generally feel okay during an infection and don’t need specific treatment.

However, if the child experiences joint pain (also known as arthropathy), medicines called Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can be used to help alleviate the discomfort. And in severe cases where the body temporarily stops making red blood cells, a condition known as aplastic crisis, a blood transfusion can be done.

If a mother contracts this infection during the first or second week of pregnancy, it’s important for her to be closely monitored with repeated ultrasound scans to track the health and development of the fetus. In severe cases, a blood transfusion can be performed for the fetus while it’s still in the womb, if needed.

What else can Parvoviruses be?

When considering the cause of a skin condition like erythema infectiosum (also known as fifth disease), doctors may consider various other conditions that present similar symptoms. These conditions include:

• Scarlet fever
• Enteroviral infection
• Rubella (German measles)
• Still disease (a type of juvenile arthritis)
• Erysipelas (a bacterial skin infection)
• Contact dermatitis
• Kawasaki disease (a rare condition in kids that causes inflammation in the walls of some blood vessels in the body)
• Roseola infantum (a viral illness in young kids)
• Measles
• Drug eruption (a reaction caused by medication)

In addition, physicians also have to consider a number of conditions when diagnosing PPGSS, another skin condition. These conditions include:

• Meningococcal infection (a serious bacterial illness)
• Erythema multiforme (a type of hypersensitivity reaction)
• Henoch-Schonlein purpura (a disease that involves purple spots on the skin, joint pain, gastrointestinal problems, and glomerulonephritis, a type of kidney disorder)
• Painful acral erythema (a skin reaction that appears on the palms of the hands and the soles of the feet and that is usually associated with chemotherapy treatment)

Doctors need to carefully consider all these possible conditions based on the patient’s symptoms, medical history, and appropriate diagnostic tests to arrive at the correct diagnosis.

What to expect with Parvoviruses

Erythema infectiosum, a common infection, is generally mild for those in good health. However, it can lead to severe complications for individuals with compromised immune systems. In some cases, the parvovirus B19, which causes this infection, can lead to chronic anemia that needs medical treatment.

Once a person has had erythema infectiosum, they typically develop immunity, which protects them from future infections. Most of the time, PPGSS, which stands for ‘post-infection condition’, gets better on its own without any long-term effects.