High Human Bocavirus Viral Load Is Associated with Disease Severity in Children under Five Years of Age

Abstract

Human bocavirus (HBoV) is a parvovirus and detected worldwide in lower respiratory tract infections (LRTIs), but its pathogenic role in respiratory illness is still debatable due to high incidence of co-infection with other respiratory viruses. To determine the prevalence of HBoV infection in patients with LRTI in Shanghai and its correlation with disease severity, we performed a 3-year prospective study of HBoV in healthy controls, outpatients and inpatients under five years of age with X-ray diagnosed LRTIs. Nasopharyngeal aspirates were tested by PCR for common respiratory viruses and by real time PCR for HBoV subtypes 1–4. Nasopharyngeal swabs from healthy controls and serum samples and stools from inpatients were also tested for HBoV1-4 by real time PCR. Viral loads were determined by quantitative real time PCR in all HBoV positive samples. HBoV1 was detected in 7.0% of inpatients, with annual rates of 5.1%, 8.0% and 4.8% in 2010, 2011 and 2012, respectively. Respiratory syncytial virus (RSV) subtype A was the most frequent co-infection detected; HBoV1 and RSVA appeared to co-circulate with similar seasonal variations. High HBoV viral loads (>106 copies/ml) were significantly more frequent in inpatients and outpatients than in healthy controls. There was a direct correlation of high viral load with increasing disease severity in patients co-infected with HBoV1 and at least one other respiratory virus. In summary, our data suggest that HBoV1 can cause LRTIs, but symptomatic HBoV infection is only observed in the context of high viral load.

Bocavirus Infection in Children at the Current Stage. A Literature Review

“…По данным отечественных исследователей, у больных hBoV-инфекцией установлено превалирование клини-ческой формы с изолированными воспалительными поражениями ВДП (назофарингит) -75,2%, реже отме-чался острый и обструктивный бронхит (16,2 и 8,5%), заболевание бокавирусной инфекцией чаще протекало в среднетяжелой форме (84,6%) с острым началом забо-левания [18,[26][27][28].…”

“…В 2005 г. в Швеции Т. Алландером с соавт. был описан новый респира-торный вирус, принадлежащий к семейству Parvoviridae, получивший название «бокавирус человека» (human Bocavirus, hBoV), который был выделен от младенцев и детей, страдающих острыми респираторными заболевани-ями верхних и нижних дыхательных путей [4,26]. Позднее hBoV был обнаружен у 1,5-19% больных ОРЗ в Австралии, Японии, Канаде, Соединенных Штатах, Франции, Германии, Корее, Таиланде, Великобритании, Южной Африке, Китае, Швейцарии, Финляндии, Италии, Бразилии, Иордании, Нидерландах и Иране, а также у 1% здоровых лиц [5].…”

Evaluation of Viral Diagnostics on rEspiratory iNfections in ChildrEn

“…However, papers on this subject show contradictory results. There are some reports suggest that there is no relation between multiple viral ARI and disease severity [68][69][70][71] , while others indicate a higher disease severity in children with a mixed respiratory infection 72,73 .…”

“…Sommige onderzoekers suggereren een positieve relatie hiertussen [63][64][65][66][67][68][69][70][71][72] , terwijl anderen die relatie niet zien [73][74][75][76][77][78] In de kindergeneeskunde praktijk is virale diagnostiek vaak gebruikt als een enkelvoudige meting bij eerste presentatie van een kind op de spoedeisende hulpafdeling of polikliniek. Deze omstandigheden zijn echter niet optimaal om de relatie tussen viral load en ziekte-ernst te bestuderen, omdat viral load een dynamisch proces is.…”

Human Bocavirus 1 Infection: Clinical Cases

“…Retrospective studies based on detection of HBoV1 infection and its correlation with signs and symptoms registered at the events of positive samples showed that the primary infection causes illness in children [19,20]. Additionally, symptoms have been shown to depend on high viral loads [10,[21][22][23][24]. However, HBoV1 natural history of infection and the genuine clinical manifestations associated remain challenging, especially in the scenario of a persistent infection.…”