What is Parvovirus (Parvo) in humans?

From the Guidelines

Parvovirus in humans is a viral infection that can cause fetal anemia and nonimmune hydrops fetalis (NIHF) in pregnant women, particularly if the infection occurs in the early second trimester.

Causes and Effects of Parvovirus Infection

• The virus has a predilection for erythroid progenitor cells, leading to inhibition of erythropoiesis and resultant anemia 1.
• The risk of a poor outcome for the fetus is greatest when the congenital infection occurs before 20 weeks of gestation, with a reported risk of fetal death of 15% at 13-20 weeks of gestation, and 6% after 20 weeks of gestation 1.
• In most cases, the anemia is transient, but in severe cases, fetal intravascular transfusion may be needed to support the fetus through this aplastic crisis 1.

Diagnosis and Management

• Diagnosis of parvovirus infection can be made by detection of the virus through PCR testing 1.
• Fetal intrauterine transfusion is recommended for NIHF due to parvovirus infection, unless the pregnancy is at an advanced gestational age and risks associated with delivery are considered to be less than those associated with the procedure 1.
• The survival rate for fetuses with hydrops or severe anemia caused by parvovirus infection is reported to be around 70-80% with intrauterine transfusion 1.

From the Research

Definition and Overview of Parvovirus (Parvo) in Humans

• Parvovirus B19 (B19V) is a significant human pathogen that causes a wide range of clinical manifestations, particularly in children and pregnant women 2.
• It is the only human pathogen in the family Parvoviridae, characterized as an autonomously replicating small single-stranded non-enveloped DNA virus 3.

Clinical Manifestations

• The infection can lead to severe complications, including transient aplastic crisis in individuals with chronic hemolytic anemias, arthralgia, and more severe joint diseases 2.
• B19V is associated with a variety of organ system involvements, including cardiac, neurological, hepatic, and renal complications, which can range from mild to life-threatening 2.
• In healthy immunocompetent individuals, B19 is the cause of erythema infectiosum and, particularly in adults, acute symmetric polyarthropathy 4.
• The virus can also cause persistent infections in immunocompromised hosts, leading to pure red cell aplasia and chronic anemia 4.

Transmission and Diagnosis

• The virus is transmitted through the upper respiratory tract by droplets, transfusion of blood or its components, and transplacentally 3.
• Detection of IgM antibodies is most important in serological diagnosis, and viral DNA can be detected by polymerase chain reaction (PCR) or hybridization procedures in patients' sera or infected tissues 3.

Treatment and Prevention

• Intravenous immunoglobulin can be used in the treatment as well as in prophylaxis of B19V infection 3.
• Vaccine phase I trials have shown promising results, but no specific antiviral treatment or vaccine is currently available, making early recognition and prompt management crucial for improving patient outcomes 2, 4.