At a glance
Also known as
Parvovirus; Fifth Disease test; Parvo B19
Why get tested?
To determine if you have, or recently had, a parvovirus B19 infection if you are at increased risk of complications from this infection
When to get tested?
When a pregnant woman has been exposed to someone with parvovirus B19; when a person, especially an person, has persistent or severe anaemia
A blood sample drawn from a vein in your arm for parvovirus B19 antibody testing; to detect the virus itself, the sample may be blood or, rarely, bone marrow
Test preparation needed?
What is being tested?
Parvovirus B19 is a that causes a common childhood illness, also called "fifth disease" or "erythema infectiosum." The virus is found in respiratory droplets during an infection and is easily transmitted to others through close physical contact. The infection typically has an incubation period of several days to two to three weeks, is active for a short period of time, and then begins to resolve.
For most people, parvovirus B19 infection is indistinguishable from other mild illnesses that develop and go away within a short time period. Many who are infected have no symptoms or have mild flu-like symptoms such as fatigue, a slight fever, headache, or an upset stomach, and many may not know that they have had a parvovirus B19 infection. The majority of people do not experience any significant symptoms or health problems and once the initial infection resolves, the person becomes immune and will not get the infection again.
Some children with the infection develop a characteristic and distinctive bright red "slapped-cheek" rash on both cheeks and a raised lacy rash on the trunk and extremities. The rashes may come and go for several weeks, reappearing and/or intensifying with exposure to heat and sunlight and with stress. By the time the rash appears, the child is no longer considered infectious. Parvovirus is sometimes called fifth disease because it is the fifth of six common childhood illnesses that can cause rashes.
Less commonly, some adults become infected and may develop "gloves and socks syndrome" with painful swelling of joints and reddening of the hands and feet that typically ends abruptly at the wrists and ankles. This condition usually resolves within a few weeks.
Parvovirus can also be passed from a pregnant woman to her fetus and transmitted through blood and blood products. In certain instances, the infection can lead to more serious disorders.
Parvovirus B19 can cause major health problems in three types of patients:
- People with iron deficiency anaemia or a condition that affects or shortens the life of red blood cells (RBCs), such as sickle cell anaemia or thalassaemia, may develop severe anaemia during a parvovirus B19 infection. Parvovirus B19 targets cells in the bone marrow that become RBCs and disrupts the production of new RBCs, which may affect those with underlying blood disorders more severely.
- Women who are infected during pregnancy can pass the infection to their baby. Most fetuses will be fine, but a small percentage will develop severe anaemia and a few may have an inflammation and infection of the heart muscle (myocarditis). These conditions can cause congestive heart failure in the fetus, miscarriage, hydrops fetalis - associated with fluid accumulation, and sometimes stillbirth. Parvovirus B19 is one of the most common causes of hydrops fetalis in Australia. The greatest risk for fetal complications is during the second trimester of pregnancy.
- In those with compromised immune systems, a parvovirus B19 infection may cause anaemia and be challenging to resolve. This includes people with HIV/AIDS, those who have had organ or bone marrow transplants, and those undergoing chemotherapy treatment for cancer.
Parvovirus B19 testing is not typically used to screen the general population. It is usually ordered to determine whether someone is currently, or has recently been, infected with parvovirus if they are at risk of complications. It may also sometimes be ordered to determine whether someone has ever been exposed to parvovirus. Testing involves either a measurement of parvovirus , immune proteins produced in response to parvovirus B19 exposure, or the detection of the genetic material of the virus itself (its ) during an active infection.
How is the sample collected for testing?
The sample required depends on whether testing is being done to determine the presence of antibody or to detect the virus itself and on the health status of the patient. Antibody testing requires a blood sample, obtained by inserting a needle into a vein in the arm. Viral detection may be done on blood or more rarely on a sample of bone marrow collected through a bone marrow aspiration or biopsy. Testing may be done on amniotic fluid in women with a fetus affected by hydrops fetalis.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.