Human Parainfluenza Virus 3 - Symptoms and illnesses
Parainfluenza virus type 3 is one of a group of common viruses known as human parainfluenza viruses (HPIV) that cause a variety of respiratory illnesses. Symptoms usually develop between 2 and 7 days from the time of exposure and typically resolve in 7-10 days. Symptoms may include fever, runny nose, and cough. HPIV-3 can also cause bronchiolitis, bronchitis, and pneumonia. Infants and young children are particularly susceptible to HPIV-3 infections, though older adults and those with a weakened immune system are also at risk for complications. HPIVs are usually spread from an infected person to others through coughing, sneezing, and/or touching. Most adults have antibodies against parainfluenza but can get repeat infections. The incubation period, the time from getting infected with HPIV to onset of symptoms, is generally 2 to 6 days. HPIV-1 and HPIV-2 are most often associated with croup, with HPIV-1 most often identified as the cause in children. Both can also cause upper and lower respiratory illness and cold-like symptoms. HPIV-3 is more often associated with bronchiolitis, bronchitis, and pneumonia. HPIV-4 is recognized less often but may cause mild to severe respiratory tract illnesses. Upper respiratory illness from any HPIV is generally common cold symptoms. Signs and symptoms may include:
Reinfections
People can get multiple HPIV infections in their lifetime. These reinfections usually cause mild upper respiratory tract illness with cold-like symptoms. However, reinfections can cause serious lower respiratory tract illness, such as pneumonia, bronchitis, and bronchiolitis in some people. Older adults and people with weakened immune systems have a higher risk for severe infections. Most children 5 years of age and older have antibodies against HPIV-3 and approximately 75% have antibodies against HPIV-1 and HPIV-2.
Transmission
HPIVs usually spread by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. HPIVs may remain infectious in airborne droplets for over an hour and on surfaces for a few hours depending on environmental conditions. People are most contagious during the early stage of illness.
HPIV Seasons
Prevention and treatment
Overview
