Department: COMBATING INFECTION
BELONGING to the Parvoviridae virus family, human bocavirus (HBoV) was discovered in 2005.1 This emerging infectious disease is associated with respiratory tract infections, particularly in children, and is one of only two known human parvovirus pathogens.2 Studies have found a 5% to 10% prevalence of HBoV among children worldwide with upper or lower respiratory tract infections, mostly during winter.3 Because HBoV is usually associated with other respiratory viruses, it's difficult to determine if it's the cause of the respiratory tract infection or simply a "passenger" virus. (See What recent studies reveal for more information on the virus.)
Diagnosis and treatment
Common signs and symptoms of HBoV mimic those of a typical respiratory infection: cough, fever, and rhinorrhea. In patients with more severe lower respiratory tract disease, you may find wheezing, tachypnea, and grunting (in younger children) on physical exam. About 25% of patients experience some form of gastroenteritis in addition to respiratory symptoms.2 There are currently no diagnostic tests for HBoV.
No specific treatment is currently available for HBoV infection, and care is primarily supportive. Be alert to worsening signs and symptoms including tachypnea, wheezing, cough, crackles, use of accessory muscles of respiration, and nasal flaring. Supportive care depends on the patient's clinical status and may include I.V. therapy, supplemental oxygen, bronchodilators, nebulizer therapy, and corticosteroids. Some patients may require more aggressive respiratory therapy such as continuous positive airway pressure or even endotracheal intubation and mechanical ventilation.2 Because illness may or may not be due to this specific virus and may also be concurrent with a bacterial infection, antibiotics may be prescribed. As more information is discovered about this virus, more specific measures may become available.
Prevention and control
No recommendations for isolation for HBoV have been developed because it may be only one of many agents causing respiratory illness in children. Take precautions to prevent contact with oral or respiratory secretions, regardless of the known or suspected pathogen. The CDC recommends implementing contact and droplet precautions in addition to standard precautions for infants and young children with respiratory infections, particularly bronchiolitis and pneumonia (including respiratory syncytial virus, parainfluenza virus, adenovirus, and influenza). Discontinue droplet precautions when adenovirus and influenza have been ruled out.4
Because HBoV has been found in stool, it could be transmitted to others via fecal-oral contact. As always, practice proper hand hygiene and maintain contact precautions (which includes gloves) to avoid possible infection.
WHAT RECENT STUDIES REVEAL
A Dutch study of 78 pediatric intensive care patients found the overall prevalence of HBoV to be 5.1%, with the prevalence in healthy controls to be 4.8%. Among the hospitalized group, only 1 of 78 patients had HBoV alone; all others had multiple viruses present, indicating that HBoV may not have been the causative agent of the acute illness.5 Other studies have found rates of carriage, with and without symptoms, to be from 1% to 19% positive on viral culture.6 A serum antibody study in Japan found antibodies to HBoV to be as high as 71%, with young children having the lowest rates and adults having the highest. This probably indicates past infection of wide prevalence. The current knowledge of HBoV infection suggests that the virus is sometimes a passenger and sometimes a pathogen in acute respiratory tract disease.6
Another study reported that of 91 tonsil and adenoid tissue samples from children undergoing elective tonsillectomy and/or adenoidectomy, 5.5% were found to have HBoV DNA, indicating that the virus can persist in tonsillar tissue after the acute phase of illness has passed.7
1. Kahn J. Human bocavirus: clinical significance and implications. Curr Opin Pediatr.
2. Bennett NJ, Domachowske J. Bocavirus
3. Foulongne V, Seqondy M. Human bocavirus (HBoV). Pathol Biol (Paris)
4. Siegel JD, Rhinehart E, Jackson M, Chiarello L. Healthcare Infection Control Practices Advisory Committee. 2007 guideline for isolation precautions: preventing transmission of infectious agents in health settings
5. van de Pol AC, Wolfs TF, Jansen NJ, Kimpen JL, van Loon AM, Rossen JW. Human bocavirus and KI/WU polyomaviruses in pediatric intensive care patients. Emerg Infect Dis
6. Schildgen O, Muller A, Allander T, et al. Human bocavirus: passenger or pathogen in acute respiratory tract infections? Clin Microbiol Rev
7. Clement N, Battaglioli G, Jensen RL, et al. Presence of human bocavirus in human tonsils and adenoids [letter]. Emerg Infect Dis