Human Bocavirus Is Not A Clinically Significant Human Pathogen Essay Samples

Introduction

The human Bocavirus (HBoV) is a novelty in the medical field as it was just a recently discovered pathogen in 2005. Liu (2011) indicated that its origin is from the Parvoviridae family of virus, which manifestations can be widespread, depending upon the immunologic and hematologic status of the host. The HBoV is also identified to occur with co-infection with other viruses that cause respiratory disease, but there has been indication that it is not a main causative factor for respiratory disease as the virus is also detected in gastroenteritis. There are growing debates about the HBoV epidemiologic contribution in respiratory disease and in gastroenteritis based on its clinical presentation, which this paper seeks to obtain better clinical insights based on the various literatures and clinical studies about the human Bocavirus.

Discussion

The human Bocavirus is highly associated with the common respiratory tract infection and gastrointestinal disease. However, there are few clinical studies that could provide an accurate finding that will point out the specific role of the virus in these diseases. The HBoV enters the host through the respiratory tract and it reaches the bloodstream. It can reach the gastrointestinal tract through ingestion of the virus or via the bloodstream. The human Bocavirus as a causative factor in upper and lower respiratory tract infections is debatable after researchers were faced with conflicting findings that the virus is a mere harmless bystander instead of a true pathogen (Schildgen, 2013). This hypothesis is based on the fact that the discovery of the HBoV was always with the co-infection of other viruses that cause respiratory tract infections. Clinical reports provide that the human Bocavirus is not related to any human respiratory disease pathogens, but is closely identified to be associated with viruses that have already an established pathogenic potential. According to Schildgen, et.al (2008), while respiratory tract samples show the presence of the virus, there is no guarantee to indicate accurately that the human Bocavirus is a causative factor of acute respiratory tract infections. The correlation of the HBoV is high respiratory tract infections, but it is highly debatable to indicate that it is a causative factor in the occurrence of respiratory diseases because its prevalence is always detected in the presence of other respiratory disease causing viruses in diagnosis. Christensen, et al. (2008) pointed out that among HBoV infected children, about 78% of them have multiple viral infections. Among the other viruses that are discovered to be present with the human Bocavirus are the Coronavirus, enterovirus, rhinovirus, and the RS virus. The higher the co-infection, the more prevalent the HBoV infection present. This finding is consistent with the clinical studies conducted by Wang, et.al (2010), showing that the HBoV infection always occurs with co-infection present of other respiratory disease causing viruses among children with respiratory tract symptoms. Thus, whether or not the human Bicavirus is primarily responsible for the respiratory tract infections remains unclear and highly debatable.
The virus was first detected in lower respiratory tract infections (LRTI) with the manifestation of higher rate of neutrophils in the white blood cells, which is a unique characteristic of HBoV positive lower respiratory tract infections. This laboratory findings show some pathogenic potential of HBoV in young children with the LRTI (Moriyama, 2010). Due to this clinical observation, some researchers hypothesized that the HBoV can be an important causative agent of LRTI among children. The HBoV infection in children with both upper and lower respiratory tract infections was found to be in conjunction with viral respiratory infection complications, such as asthma, pneumonia, acute otitis media with high prevalence of respiratory distress and hypoxia that are highly associated with broncholitis. This supports the fact that the HBoV may directly infect the lower respiratory tract, although it has been emphasized by Arnold, Singh, Spector and Sawyer (2015) that further studies are needed in order to establish HBoV as the causative agent in LRTI. Deng, et. al (2012) supports the same finding hypothesizing that the HBoV can have a significant role in causing the LRTI among children. They postulate that the high viral load can be an etiologic agent for LRTI that can cause wheezing and long term hospitalization. To support this hypothesis, the researchers further pointed out that the HBoV is present even among children with asymptomatic respiratory tract secretions. However, although there is a strong indication that the HBoV was confirmed to be present in respiratory tract aspirates in LRTI, the role of the virus as an etiologic agent is frequently questioned by many researchers. The clinical study of Allander, et.al (2007) also supports the finding that the human Bocavirus with high viral loads can be associated with respiratory tract infections, while those with a low viral load may indicate viral shedding. The presence of the virus is often associated with the symptom of wheezing among asymptomatic children with respiratory disease. Moreover, the study pointed out that the HBoV is more prevalent among children with symptoms of otherwise unexplained etiology than those where other viruses were detected. The HBoV is considered to be the fourth most common viruses that are frequently detected after the presence of pathogenetically established viruses known to cause respiratory infections has been identified. This hypothesis has been challenged by Venermo, et.al (2009) providing that there is no concrete indication to associate HBoV as a causative agent as there is a lack of study to show whether the co-infection of HBoV with other viruses is a sequential infection or a simultaneous viral infection.
While the role of the human Bocavirus as a causative agent remains unclear, many studies reveal that the virus is consistently detected in various respiratory diseases which increases its potential as a causative agent. Manning, et.al (2006) provides that the area of clinical research of identifying HBoV infections must be pursued as this can be clinically important in the future. According to their research, there is a high predominance of the HBoV infections among children, with the prevalence substantially higher than the researches made in the past. It was likewise pointed out in the research that the rate of co-infection is also higher.
The human Bicavirus is also detected in fecal samples, which indicates its presence in the gastrointestinal tract. While researchers are contemplating to consider the role of HBoV in gastroenteritis, it is difficult to establish its role as a causative agent owing to the presence of other viruses present in the fecal samples, such as the diarheal pathogens like the rotavirus, B. Salmonella, Campylobacter and staphylococcus aureus (Lau, 2007). It is common to find the human Bocavirus to be present in patients with gastroenteritis without any respiratory infections based on the fecal samples. This clinical manifestation of the HBoV likewise directed the interest of researchers to conduct further studies about the human Bocavirus as a potential pathogen in gastroenteritis. The most commonly identified symptoms are diarrhea and fever.
The virus was also detected in the respiratory secretions, serum and stools in stem cell transplant recipients, although it remains unclear how the virus disseminated the infection (Kahn, 2008). This is another area of potential research to discover the potential of the human Bocavirus to cause viremia, which is the presence of virus in the blood (Diallo, 2005) during an infection. In a study of Wang, et. al. (2010), the anti-HBoV IgM antibodies were detected in patients viremic for HBoV or those with a high presence of the virus in their nasal and throat swabs. About 90.9% of patients in the study showed to be IgM positive. The presence of IgM level is seen to be highest among children with a lower respiratory tract infection and pneumonia and the acute level of HBoV is seen among these patients. Thus, it can be pointed out that the virus-specific IgM antibodies can be an additional marker to the acute infections manifested among the HBOv positive patients (Karalar, 2010). An attempt was also made to study the role of the human Bocavirus in chronic obstructive pulmonary disease (COPD) in relation to the prevalence of the human Bocavirus in upper and lower respiratory tracts. However, there is a very low frequency for the HBoV to be present in the COPD acute exacerbations, making it unlikely to consider HBoV as a trigger to the disease (Ringshausens, et. al. 2009). Another potential condition where HBoV is suspected to have an etiological association is the Kawasaki disease. The area of consideration is on the genetic susceptibility of children with Kawasaki disease as a result of hyper immune reaction. While the human Bocavirus was detected in Kawasaki disease, the presence of suspected viral agents like the Adenovirus, Parvovirus, Parainfluenza virus, HIV, measles, Varicella-zoster virus and Rotavirus were not isolated (Santos, et. al. 2010).

Conclusion

In conclusion, the human Bocavirus is a novelty in the field of medicine. Although its presence in respiratory diseases and gastroenteritis has been identified, its role as a causative agent remains questionable and doubtful. This observation is however not conclusive to state that the human Bocavirus has not established itself as a potential pathogenic agent in respiratory diseases (Farrar, 2009). Owing to the prevalence of co-infection with other viruses, the role of the human Bocavirus as an etiology of respiratory disease remains clinically insignificant. There is no study as yet to establish the independent role of the virus to cause respiratory and gastrointestinal diseases, therefore it is premature to conclude its significant role in the occurrence of both respiratory diseases and gastroenteritis.
Various clinical studies already confirmed that the human Bocavirus is acquired early in life, after its detection among children (Acton, 2012). Despite the attempts of various clinical studies to present the role of the human Bocavirus in respiratory diseases and gastroenteritis, the presence of co-infection with other pathogenetically established viruses will bring cloud of doubts about its clinical significance in the manifestation of the diseases. Thus, the high presence of co-infections with the other respiratory viruses may complicate the analysis of the clinical studies made on the human Bocavirus (Guido, 2011). More studies must be taken further in order to isolate the role of the virus without being highly associated with the presence of other viruses in the clinical diagnosis in order to fully establish its role as a human pathogen. Until the association of the human Bocavirus with co-infection is completely eliminated, it can be concluded that the virus is not a clinically significant human pathogen.

References:

Acton, A. 2012. Bocavirus Advances in research and application. Georgia: Scholarly Editions.
Allander, et.al (2006). Human bocavirus and acute wheezing in children. Clinical Infectious Disease. 44:904-910.
Arnold, J.C., Singh, K.K., Spector, S.A. and Sawyer, M.H. 2015. Human bocavirus:Prevalence and clinical spectrum at a Children’s Hospital. Clinical infectious disease. 43:283-288.
Christensen, A. et al. 2008. Human bocavirus commonly involved in multiple viral airway infections. Journal of clinical virology. 41: 34-37.
Deng, Y. et. al. 2012. High viral load of boavirus correlates with duration of wheezing in children with severe lower respiratory tract infection. PlosOne. 7(3):1-7.
Diallo, A. 2005. Microbiology Recall. Maryland: Lippincott Williams and Wilkins.
Farrar, J. 2009. Manson;s Tropical Diseases. 23rd Ed. China: Elsevier.
Guido, M. 2011. Seroepidemiology of human bocavirus in Apulia, Italy. Clinical Microbial Infection. 18:74-76.
Kahn, J. 2008. Human bocavirus: Clinical significance and implications. Current opinion in pediatrics. 20:62-66.
Karalar, L. 2010. Prevalence and clinical aspects of human bocavirus infection in children. Clinical Microbial Infection. 16: 633-639.
Lau, S.K. 2007. Clinical and molecular epidemiology of human bocavirus in respiratory and fecal samples from children in Hong Kong. The Journal of Infectious Disease. 196: 986-993.
Liu, D. 2011. Molecular detection of human viral pathogens. Florida: CRC Press.
Manning, A. et.al. 2006. The Journal of infectious disease. 194: 1283-1290.
Moriyama, Y. 2010. Distinctive clinical features of human bocavirus in children younger than 2 years old. European Journal Pediatrics. 169: 1087-1092.
Ringshausen, F.C. et. al. 2009. Frequency and clinical relevance of human bocavirus infection in acute exacerbation of COPD. International Journal of COPD. 4: 11-117.
Santos, R. et. al. 2010. Kawasaki Disease and the Human Bocavirus – Potential Association. Journal of Microbiology Immunology and Infection.
Schildgen, O. 2013. Human Bocavirus: Lesson learned today. Pathogens. 2:1-12.
Schildgen, O. et.al. 2008. Human Bocavirus: Passenger or pathogen in acute respiratory tract infections? Clinical Microbiology Review. 21(2): 291-304.
Venermo, M. et.al. 2009. Clinical assessment and improved diagnosis of Bocavirus induced wheezing in children, Finland. Emerging infectious disease. 15(9): 1423-1430.
Wang, K. et. al. 2010. Correlation between Bocavirus infection and humoral response and co-infection with other respiratory viruses in children with acute respiratory infection. Journal of clinical virology. 47:148-155.