B19 virus causes following clinical syndromes: (a) flu-like illness, (b) erythema infectiosum or fifth disease, (c) infection in pregnant women, and (d) chronic B19 infection.
B19 virus most commonly causes a flu-like illness. Malaise, headache, myalgia, and rhinorrhea are the common symptoms.
B19 virus is an additional causative agent of erythema infec-tiosum or fifth disease, the condition seen most commonly in children. The infection begins with nonspecific symptoms, followed by appearance of a distinctive rash on fifth day of infection. A bright red rash develops on both cheeks that appear as they have been slapped. The rash then appears on the trunk, which spreads gradually toward the arms and legs. The condition usually subsides within 1–2 weeks.
Aplastic anemia: Transient but severe aplastic anemia canoccur in children with chronic anemia, such as sickle cell anemia, thalassemia, and spherocytosis (aplastic crisis) after infection with B19 virus. Gloves and sock syndrome is another serious complication caused by B19 virus. In this syndrome, erythematous exanthema appears on the hands and feet, with a well-defined margin on the wrist and ankle joints.
If the B19 virus causes reinfection in a pregnant mother who is infected earlier by the same virus and is already immune to the virus (showing positive B19 antibodies), then no adverse effects are seen in the fetus. In nonimmune seronegative preg-nant mothers, B19 virus infection is increasingly associated with risk for fetal death. The infection may cause severe anemia in the fetus and subsequently, the fetus may develop signs of high-output cardiac failure (hydrops fetalis). B19 virus, however, does not cause any congenital anomalies in the fetus.
This infection occurs in immunocompromised patients, such as patients with HIV, those receiving immunosuppressive ther-apy, and transplant patients. Chronic anemia, leukopenia, and thrombocytopenia are the common manifestations.