Reconstruction of the historic time course of blood-borne virus contamination of clotting factor concentrates, 1974-1992.

Factor VIII and IX clotting factor concentrates manufactured from pooled plasma have been identified as potent sources of virus infection in persons with hemophilia (PWHs) in the 1970s and 1980s. To investigate the range and diversity of viruses over this period, we analysed 24 clotting factor concentrates for several blood-borne viruses. Nucleic acid was extracted from 14 commercially produced clotting factors and 10 from nonremunerated donors, preserved in lyophilized form (expiry dates: 1974-1992). Clotting factors were tested by commercial and in-house quantitative PCRs for blood-borne viruses hepatitis A, B, C and E viruses (HAV, HBV, HCV, HEV), HIV- types 1/2, parvoviruses B19V and PARV4, and human pegiviruses types 1 and 2 (HPgV-1,-2). HCV and HPgV-1 were the most frequently detected viruses (both 14/24 tested) primarily in commercial clotting factors, with frequently extremely high viral loads in the late 1970s-1985 and a diverse range of HCV genotypes. Detection frequencies sharply declined following introduction of virus inactivation. HIV-1, HBV, and HAV were less frequently detected (3/24, 1/24, and 1/24 respectively); none were positive for HEV. Contrastingly, B19V and PARV4 were detected throughout the study period, even after introduction of dry heat treatment, consistent with ongoing documented transmission to PWHs into the early 1990s. While hemophilia treatment is now largely based on recombinant factor VIII/IX in the UK and elsewhere, the comprehensive screen of historical plasma-derived clotting factors reveals extensive exposure of PWHs to blood-borne viruses throughout 1970s-early 1990s, and the epidemiological and manufacturing parameters that influenced clotting factor contamination.

Human parvovirus 4 prevalence among HTLV-1/2 infected individuals in Brazil.

Human parvovirus 4 (PARV4), a Tetraparvovirus, has been largely found in HIV, HBV, or HCV infected individuals. However, there is no data for the PARV4 occurrence in Human T-lymphotropic virus (HTLV-1/2) infected individuals, despite similar transmission routes. Here, PARV4 viremia was evaluated in 130 HTLV infected patients under care of a Brazilian HTLV outpatient clinic. PARV4 viremia was detected in 6.2% of the HTLV-1 infected patients. Most PARV4 positives showed no evidence for parenterally transmitted infections. It is suggested that in Brazil, transmission routes of PARV4 are more complex than in Europe and North America and resemble those in Africa. J. Med. Virol. 89:748-752, 2017. © 2016 Wiley Periodicals, Inc.

Parvovirus B19 and Parvovirus 4 infections among healthy blood donors; A prevalence report from Iran.

Background: Parvoviruses, characterized by their tropism for blood cells, can manifest as asymptomatic infections. With their ability to persist in blood, assessing the prevalence of Parvovirus B19 (B19V) and Parvovirus 4 (PARV4) among healthy blood donors is essential for evaluating the potential transmission risks through blood transfusions, emphasizing the need for comprehensive screening protocols. Methods: Four hundred blood donors participated in the study, with their blood specimens subjected to Real-Time PCR analysis for B19V and PARV4 nucleic acids after obtaining informed consent. Additionally, Complete Blood Count (CBC) assessments and determination of anti-B19 V-IgM and anti-B19 V-IgG antibody titers were performed using Enzyme-Linked Immunosorbent Assay (ELISA) for all collected samples. Results: The results reveal that 12 out of 400 individuals (3 %) exhibited positive results for B19V DNA, while 6 out of 400 individuals (1.5 %) tested positive for PARV4 DNA. Additionally, 8 out of 400 individuals (2 %) displayed positive results for anti-B19V IgM, and 306 out of 400 individuals (76.5 %) exhibited positive results for anti-B19 IgG. Notably, one donation from a donor presenting anti-IgM antibodies was subsequently confirmed as B19V DNA-positive through Real-Time PCR. In the analysis of CBC, a significant disparity in platelet levels was observed between B19V-positive donors, PARV4-positive donors, and B19V-negative donors. Conclusions: The study suggests that individuals at high risk, lacking detectable B19V antibodies, should undergo systematic screening and exclusion. This precaution is intended to minimize potential contamination risks within the studied cohort, despite the undefined pathogenesis and clinical implications of PARV4.

Capsid Structure of Aleutian Mink Disease Virus and Human Parvovirus 4: New Faces in the Parvovirus Family Portrait.

Parvoviruses are small, single-stranded DNA viruses with non-enveloped capsids. Determining the capsid structures provides a framework for annotating regions important to the viral life cycle. Aleutian mink disease virus (AMDV), a pathogen in minks, and human parvovirus 4 (PARV4), infecting humans, are parvoviruses belonging to the genera Amdoparvovirus and Tetraparvovirus, respectively. While Aleutian mink disease caused by AMDV is a major threat to mink farming, no clear clinical manifestations have been established following infection with PARV4 in humans. Here, the capsid structures of AMDV and PARV4 were determined via cryo-electron microscopy at 2.37 and 3.12 Å resolutions, respectively. Despite low amino acid sequence identities (10-30%) both viruses share the icosahedral nature of parvovirus capsids, with 60 viral proteins (VPs) assembling the capsid via two-, three-, and five-fold symmetry VP-related interactions, but display major structural variabilities in the surface loops when the capsid structures are superposed onto other parvoviruses. The capsid structures of AMDV and PARV4 will add to current knowledge of the structural platform for parvoviruses and permit future functional annotation of these viruses, which will help in understanding their infection mechanisms at a molecular level for the development of diagnostics and therapeutics.

Bocaparvovirus, Erythroparvovirus and Tetraparvovirus in New World Primates from Central America.

Parvoviruses in the genera Bocaparvovirus (HBoV), Erythroparvovirus (B19) and Tetraparvovirus (PARV4) are the only autonomous parvoviruses known to be associated with human and non-human primates based on studies and clinical cases in humans worldwide and non-human primates in Asia and Africa. Here, the presence of these agents with pathogenic potential was assessed by PCR in blood and faeces from 55 howler monkeys, 112 white-face monkeys, 3 squirrel monkeys and 127 spider monkeys in Costa Rica and El Salvador. Overall, 3.7% (11/297) of the monkeys had HboV DNA, 0.67% (2/297) had B19 DNA, and 14.1% (42/297) had PARV4 DNA, representing the first detection of these viruses in New World Primates (NWP). Sex was significantly associated with the presence of HBoV, males having greater risk up to nine times compared with females. Captivity was associated with increased prevalence for PARV4 and when all viruses were analysed together. This study provides compelling molecular evidence of parvoviruses in NWPs and underscores the importance of future research aimed at understanding how these viruses behave in natural environments of the Neotropics and what variables may favour their presence and transmission.

Human parvovirus 4 'PARV4' remains elusive despite a decade of study.

Human parvovirus 4 ('PARV4') is a small DNA tetraparvovirus, first reported in 2005. In some populations, PARV4 infection is uncommon, and evidence of exposure is found only in individuals with risk factors for parenteral infection who are infected with other blood-borne viruses. In other settings, seroprevalence studies suggest an endemic, age-associated transmission pattern, independent of any specific risk factors. The clinical impact of PARV4 infection remains uncertain, but reported disease associations include an influenza-like syndrome, encephalitis, acceleration of HIV disease, and foetal hydrops. In this review, we set out to report progress updates from the recent literature, focusing on the investigation of cohorts in different geographical settings, now including insights from Asia, the Middle East, and South America, and discussing whether attributes of viral or host populations underpin the striking differences in epidemiology. We review progress in understanding viral phylogeny and biology, approaches to diagnostics, and insights that might be gained from studies of closely related animal pathogens. Crucial questions about pathogenicity remain unanswered, but we highlight new evidence supporting a possible link between PARV4 and an encephalitis syndrome. The unequivocal evidence that PARV4 is endemic in certain populations should drive ongoing research efforts to understand risk factors and routes of transmission and to gain new insights into the impact of this virus on human health.

Frequency of human parvovirus 4 (PARV4) viremia among HBV-infected patients and healthy donors in Shiraz, Iran.

BACKGROUND/AIM: PARV4, a small DNA virus belonging to the family Parvoviridae, was first isolated in an HBV injecting drug user. Several studies have investigated PARV4 co-infection with HBV and HCV and its effect on the progression of liver disease. The aim of this study was to determine the frequency of PARV4 among HBV-infected patients and healthy individuals. MATERIALS AND METHODS: A group of 90 HBV patients and a group of 90 healthy subjects were included in this study. Samples were selected after screening tests such as HBsAg ELISA, anti-HCV ELISA, and anti-HIV ELISA. Nested-PCRs were conducted to detect the PARV4 genome. Positive samples were then subjected to DNA sequencing. RESULTS: PARV4 DNA was detected in 4.4% of HBV patients in comparison with 1.1% of healthy individuals (P-value: 0.36). DNA sequencing results revealed that PARV4 in all five positive samples was genotype I.Conclusions: Although this pilot study showed no significant difference between the frequency of PARV4 among HBV patients and healthy donors, further studies with a larger sample size are suggested to determine the association of PARV4 with HBV co-infection and the impact of this virus on the progression of liver disease in patients with hepatitis B.

Human parvovirus B19 and parvovirus 4 among Iranian patients with hemophilia.

BACKGROUND: Human parvovirus B19 (B19V) is one of the smallest DNA viruses and shows great resistance to most disinfectants. Therefore, it is one of the common contaminant pathogens present in blood and plasma products. Parvovirus 4 (PARV4) is a newly identified parvovirus, which is also prevalent in parenteral transmission. In this study, we aimed to evaluate the prevalence of B19V and PARV4 DNA among patients with hemophilia in Birjand County in eastern Iran. METHODS: This was a cross-sectional epidemiological study comprising nearly all people with hemophilia in this region. Whole blood samples were taken after patient registration and sent for plasma isolation. After nucleic acid extraction, B19V was detected with real-time polymerase chain reaction, PARV4 DNA was then detected using sensitive semi-nested PCR. RESULTS: In total, there were 86 patients with hemophilia, with mean age 28.5±1.5 years. Of these, 90.7% were men and 9.3% women; 84.9% had hemophilia A and 7.0% had hemophilia B. We found 11 patients (12.8%) were positive for B19V DNA and 8 were positive (9.3%) for PARV4 DNA. The prevalence of B19V was higher in middle-aged groups rather than younger people, whereas PARV4 infection was more common in younger patients (P <0.05). CONCLUSION: There was a high prevalence of B19V and PARV4 infection in this high-risk group of patients with hemophilia. Due to the clinical significance of the B19 virus, imposing more precautionary measures for serum and blood products is recommended.

PARV4 prevalence, phylogeny, immunology and coinfection with HIV, HBV and HCV in a multicentre African cohort.

Background: The seroprevalence of human parvovirus-4 (PARV4) varies considerably by region. In sub-Saharan Africa, seroprevalence is high in the general population, but little is known about the transmission routes or the prevalence of coinfection with blood-borne viruses, HBV, HCV and HIV.  Methods: To further explore the characteristics of PARV4 in this setting, with a particular focus on the prevalence and significance of coinfection, we screened a cohort of 695 individuals recruited from Durban and Kimberley (South Africa) and Gaborone (Botswana) for PARV4 IgG and DNA, as well as documenting HIV, HBV and HCV status.  Results: Within these cohorts, 69% of subjects were HIV-positive. We identified no cases of HCV by PCR, but 7.4% were positive for HBsAg. PARV4 IgG was positive in 42%; seroprevalence was higher in adults (69%) compared to children (21%) (p<0.0001) and in HIV-positive (52%) compared to HIV-negative individuals (24%) (p<0.0001), but there was no association with HBsAg status. We developed an on-line tool to allow visualization of coinfection data (https://purl.oclc.org/coinfection-viz). We identified five subjects who were PCR-positive for PARV4 genotype-3. Ex vivo CD8+ T cell responses spanned the entire PARV4 proteome and we propose a novel HLA-B*57:03-restricted epitope within the NS protein.  Conclusions: This characterisation of PARV4 infection provides enhanced insights into the epidemiology of infection and co-infection in African cohorts, and provides the foundations for planning further focused studies to elucidate transmission pathways, immune responses, and the clinical significance of this organism.

Absence of novel human parvovirus (PARV4) in Danish mothers and children.

BACKGROUND: The recently discovered human parvovirus 4 (PARV4) is found most frequently in injection drug users, HIV-positive patients, and in haemophiliacs. Studies from Ghana report the finding of PARV4 in plasma from 2 to 12% of children without acute infection, and in nasal secretions and faecal samples. Studies of PARV4 in children from industrialized countries are few. OBJECTIVES: We aimed to describe the occurrence of PARV4 in a population-based birth cohort of 228 Danish mothers and their healthy children who previously participated in a study of respiratory tract infections in infancy. STUDY DESIGN: Children were included over a whole calendar year and were monitored through monthly home visits through the first year of life. Plasma samples for the present study were available from 228 mothers, 176 newborns, and 202 12-months-old children. All samples were analysed for the presence of PARV4 antibodies by enzyme immunoassay, and samples with detectable antibodies were in addition studied by real-time PCR. RESULTS: One (0.4%) of 228 mothers had PARV4 IgG exceeding the cut-off absorbance level and another had borderline IgG reactivity. No mother among these two had an acute infection, as they were IgM and PARV4 DNA negative. All blood samples from newborns and one-year-old children had IgG and IgM reactivity below cut-off. CONCLUSIONS: PARV4 is rare in Danish mothers and infants. Further studies are needed, in both rural and urban settings, to investigate the epidemiology and clinical significance of this novel human parvovirus.

A two-step real-time PCR assay for quantitation and genotyping of human parvovirus 4.

Human parvovirus 4 (PARV4) of the family Parvoviridae was discovered in a plasma sample of a patient with an undiagnosed acute infection in 2005. Currently, three PARV4 genotypes have been identified, however, with an unknown clinical significance. Interestingly, these genotypes seem to differ in epidemiology. In Northern Europe, USA and Asia, genotypes 1 and 2 have been found to occur mainly in persons with a history of injecting drug use or other parenteral exposure. In contrast, genotype 3 appears to be endemic in sub-Saharan Africa, where it infects children and adults without such risk behaviour. In this study, a novel straightforward and cost-efficient molecular assay for both quantitation and genotyping of PARV4 DNA was developed. The two-step method first applies a single-probe pan-PARV4 qPCR for screening and quantitation of this relatively rare virus, and subsequently, only the positive samples undergo a real-time PCR-based multi-probe genotyping. The new qPCR-GT method is highly sensitive and specific regardless of the genotype, and thus being suitable for studying the clinical impact and occurrence of the different PARV4 genotypes.