Parvovirus is a mild infection in humans, predominantly affecting children and to a lesser extent in adults. It causes mild rash on cheek of the affected person. There are several types of parvovirus but most of them affect animals. Parvovirus B19 is the only virus to affect humans. The disease is also called fifth disease or erythema infectiosum.
Symptoms usually appear 4 to 14 days after the organism has entered into the body. Transmission occurs from nasal, saliva and respiratory secretions when an infected patient sneezes or coughs. It is contagious in the initial stage before the appearance of rash.
The virus can also transmit through blood. Therefore if pregnant woman is infected, the baby inside her may also be affected with the virus. In majority of cases the baby remains fine without any complication. There is very less chance of miscarriage, fetal anemia due to infection.
Signs And Symptoms Of Parvo In Humans
In majority of infected children and adults the symptoms are not manifested, although the condition in its initial phase is contagious. The symptoms may vary from one patient to another. The symptoms in the beginning are similar to that cold and flu such as mild fever, body ache, running nose, sneezing, fatigue and sore throat.
A few days later rash may also appear on back, chest, buttocks, thighs and hands. Some patients complain of itching in soles with red rash. Rash disappears in one or two weeks, but can develop again due to exposure to sunlight, heat or cold or even after strenuous exercise.
Joint pain is common in adults but rare in children. Pain in small joints persists for a long time particularly in women. Adults usually do not get typical slapped cheek rash as it is seen in children. Infection can occur only once, as the patient develops immunity to the virus.
Causes Of Parvo In Humans
Parvovirus in humans is caused due to parvovirus B19. This virus is different from parvovirus that is observed in dogs and cats. The outbreaks are common in winter but it can occur at anytime of the year. The organisms are transmitted from one human being to another.
Human parvovirus spread is through saliva, sneeze and secretion of respiratory tract and hand to hand contact. Parvovirus is contagious in the initial stage but before the appearance of rash and other joint pain. Parvovirus can spread through blood. Infected pregnant women can pass the virus to the fetus through placental route.
Parvovirus Infection In Pregnancy
A pregnant woman can be infected with the virus if she has not come in contact with the virus previously. She can pass the virus to the fetus inside her with a probability of 1 in 3. In most cases the baby remains fine even if the virus has passed through the placenta.
In small number of pregnant women, the virus can cause miscarriage or anemia in fetus. In rare cases it can lead to hydrop’s, a condition in the fetus where there is excess collection of fluid in the tissue. The problems usually are more if the pregnant woman is infected in first trimester, later on they are fewer.
Diagnosis: Diagnosis in children is possible with typical slapped cheek rash. During pregnancy a blood test will reveal if the woman is immune or if she is susceptible or has suffered from recent infection. In case if the test is positive for parvovirus, further investigations such as sonogram, amniotic fluid test etc will be helpful to check the health of fetus.
Treatment Of Parvovirus Infection
Patients with parvo infection recover within few days after the infection without any treatment. There is no specific antiviral treatment for parvovirus infection. The symptoms will reduce without any medication. However, sometimes in case of severe itching in soles or joint pain patient may be recommended symptomatic treatment.
In case is there is evidence of severe fetal anemia or fluid collection in baby, doctors may treat the condition with certain procedures such as blood transfusion through umbilical cord vein. Even if the procedure is extremely risky for the fetus, there is fair chance of survival in severely fetal anemia.
In some cases where the anemia in fetus is mild, doctors just monitor regularly with certain blood test and sonography. Fetuses who have survived the condition have very little chance of birth defects or problems related to development after their birth.