Evolutionary aspects of Parvovirus B-19V associated diseases and their pathogenesis patterns with an emphasis on vaccine development

Multisystem Involvement Induced by Human Parvovirus B19 Infection in a Non-immunosuppressed Adult: A Case Report

Background

Human parvovirus B19 (B19V) infection is usually symptomless and occurs in the childhood. While in immunocompromised adults, B19V infection also presents various clinical symptoms due to the host's immune status. The classic symptoms include erythema, anemia, arthropathy, and edema, but neurological involvement is rare.

Case Presentation

In this report, we present a case of B19V infection caused multiple organ dysfunction in a non-immunosuppressed adult. Metagenomic next-generation sequencing (mNGS) was used and successfully detected the pathogen in multiple types of samples, including blood, cerebrospinal fluid (CSF), and bronchoalveolar lavage fluid (BALF). The diagnosis was subsequently confirmed by polymerase chain reaction (PCR). He was treated with intravenous gamma globulin, resulting in a significant resolution of symptoms after 1 month.

Conclusion

Multisystem involvement induced by B19V infection was found in this case report. mNGS performed great advantages in rapidly and accurately diagnosing B19V infection in multiple types of samples, which helps the timely adjustment of treatment and improves the prognosis.

Is the ZIKV Congenital Syndrome and Microcephaly Due to Syndemism with Latent Virus Coinfection?

The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.

Porcine Parvovirus 7: Evolutionary Dynamics and Identification of Epitopes toward Vaccine Design

Porcine parvovirus 7 (PPV7) belonging to the genus Chapparvovirus in the family Parvoviridae, has been identified in the USA, Sweden, Poland, China, South Korea and Brazil. Our objective was to determine the phylogeny, estimate the time of origin and evolutionary dynamics of PPV7, and use computer-based immune-informatics to assess potential epitopes of its Cap, the main antigenic viral protein, for vaccines or serology. Regarding evolutionary dynamics, PPV7 had 2 major clades, both of which possibly had a common ancestor in 2004. Furthermore, PPV7 strains from China were the most likely ancestral strains. The nucleotide substitution rates of NS1 and Cap genes were 8.01 × 10⁻⁴ and 2.19 × 10⁻³ per site per year, respectively, which were higher than those reported for PPV1-4. The antigenic profiles of PPV7 Cap were revealed and there were indications that PPV7 used antigenic shift to escape from the host’s immune surveillance. Linear B cell epitopes and CD8 T cell epitopes of Cap with good antigenic potential were identified in silico; these conserved B cell epitopes may be candidates for the PPV7 vaccine or for the development of serological diagnostic methods.