RESUMO
Canine parvovirus type 2 (CPV-2) is a relevant pathogen for dogs and causes a severe disease in carnivore species. CPV-2 reached pandemic proportions after the 1970s with the worldwide dissemination, generating antigenic and genetic variants (CPV-2a, CPV-2b, and CPV-2c) with different pathobiology in comparison with the original type CPV-2. The present study aimed to assess the current global CPV-2 molecular phylogeny and to analyze genetic diversity and temporal spreading of variants from Brazil. A total of 284 CPV-2 whole-genome sequences (WGS) and 684 VP2 complete genes (including 23 obtained in the present study) were compared to analyze phylogenetic relationships. Bayesian coalescent analysis estimated the time to the most recent common ancestor (tMRCA) and the population dynamics of the different CPV-2 lineages in the last decades. The WGS phylogenetic tree demonstrated two main clades disseminated worldwide today. The VP2 gene tree showed a total of four well-defined clades distributed in different geographic regions, including one with CPV-2 sequences exclusive from Brazil. These clades do not have a relationship with the previous classification into CPV-2a, CPV-2b, and CPV-2c, despite some having a predominance of one or more antigenic types. Temporal analysis demonstrated that the main CPV-2 clades evolved within a few years (from the 1980s to 1990s) in North America and they spread worldwide afterwards. Population dynamics analysis demonstrated that CPV-2 presented a major dissemination increase at the end of the 1980s / beginning of the 1990s followed by a period of stability and a second minor increase from 2000 to 2004.
Assuntos
Doenças do Cão/virologia , Variação Genética , Infecções por Parvoviridae/veterinária , Parvovirus Canino/genética , Filogenia , Animais , Brasil , Doenças do Cão/transmissão , Cães , Infecções por Parvoviridae/transmissão , Infecções por Parvoviridae/virologia , Parvovirus Canino/classificaçãoRESUMO
Autonomous parvoviruses are small, non-enveloped, lytic DNA viruses replicating in the nucleus of actively dividing mammalian cells of appropriate species and tissue origins. In contrast to AAV, the other main subgroup of parvoviruses, autonomous parvoviruses do not require the assistance of an auxiliary virus for productive infection and do not stably integrate in the cellular DNA. Therefore, autonomous parvoviruses are suitable vectors for mediating transient gene transduction in dividing target cells. Interestingly, some of these viruses possess a striking inherent oncotropism, which may render them particularly suitable as selective vehicles in the clinical context of cancer gene therapy. In this chapter, we will present a brief overview of the biology of autonomous parvoviruses. This topic will be followed by a description of the design and recent developments in the production and use of parvoviral vectors, with a particular emphasis on biosafety aspects. Finally, the risk assessment related to the production and use of parvoviral vectors will be discussed in last part of the chapter.
Assuntos
Vetores Genéticos/efeitos adversos , Parvovirus/genética , Medição de Risco , Infecções por Parvoviridae/transmissão , Parvovirus/fisiologia , Gestão da Segurança , Tropismo , Replicação ViralAssuntos
Doadores de Sangue , Sangue/virologia , DNA Viral/sangue , Controle de Infecções/métodos , Programas de Rastreamento/métodos , RNA Viral/sangue , Doadores de Sangue/legislação & jurisprudência , Transfusão de Sangue/legislação & jurisprudência , Transfusão de Sangue/normas , Transmissão de Doença Infecciosa/prevenção & controle , Infecções por HIV/sangue , Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , HIV-1/genética , HIV-1/isolamento & purificação , Antígenos de Superfície da Hepatite B/sangue , Vírus de Hepatite/genética , Vírus de Hepatite/isolamento & purificação , Hepatite Viral Humana/sangue , Hepatite Viral Humana/prevenção & controle , Hepatite Viral Humana/transmissão , Humanos , Controle de Infecções/legislação & jurisprudência , Licenciamento , Programas de Rastreamento/legislação & jurisprudência , Programas de Rastreamento/normas , Análise de Sequência com Séries de Oligonucleotídeos , Infecções por Parvoviridae/sangue , Infecções por Parvoviridae/prevenção & controle , Infecções por Parvoviridae/transmissão , Parvovirus B19 Humano/isolamento & purificação , Plasma , Guias de Prática Clínica como Assunto , Política Pública , Sensibilidade e Especificidade , Reação Transfusional , Inativação de VírusRESUMO
Despite the much lower actual yield than that estimated for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) nucleic acid testing (NAT)-only positives in the USA and Germany, look-back procedures have revealed that no HCV transmission has occurred in Germany since the introduction of NAT. This indicates sufficient sensitivity of the pool-PCR approach. The slow ramp-up of hepatitis B virus (HBV) however, may require a different approach. It has been shown in Germany that the pooling of samples followed by virus enrichment results in a significant yield. Single donation testing for HBV would not increase the yield, because virus enrichment from mini-pool results in a similar sensitivity to that of single donation testing. Both strategies may be useful for extending future NAT to HBV screening. New candidate viruses for NAT are Parvo B19 and hepatitis A virus (HAV) because of their extreme resistance to inactivation procedures. Their low pathogenicity and epidemiologic characteristics, however, make them candidate viruses only for pooled source plasma. The main future issues of NAT will be related to the automation of pooling, extraction and amplification as a single homogeneous process. Depending on the throughput, automated single donation NAT as demonstrated by the 'Tigris' system may be an option, as far as all transfusion-relevant viruses will be included. In the near future high throughput systems will rely on pooled donor samples, most probably in conjunction with efficient enrichment procedures. For these systems, automation of the extraction and amplification process will be one of the first steps. These procedures will also limitthe costs of NAT and keep it available for use with future candidate viruses.
Assuntos
DNA Viral/sangue , Programas de Rastreamento/métodos , RNA Viral/sangue , Viremia/diagnóstico , Fatores Biológicos/sangue , Fatores Biológicos/isolamento & purificação , Custos e Análise de Custo , Previsões , Alemanha , HIV/isolamento & purificação , Infecções por HIV/sangue , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , Hepatite B/sangue , Hepatite B/diagnóstico , Hepatite B/prevenção & controle , Hepatite B/transmissão , Vírus de Hepatite/genética , Vírus de Hepatite/isolamento & purificação , Hepatite Viral Humana/sangue , Hepatite Viral Humana/diagnóstico , Hepatite Viral Humana/prevenção & controle , Hepatite Viral Humana/transmissão , Herpesviridae/genética , Herpesviridae/isolamento & purificação , Infecções por Herpesviridae/sangue , Infecções por Herpesviridae/diagnóstico , Infecções por Herpesviridae/prevenção & controle , Infecções por Herpesviridae/transmissão , Humanos , Programas de Rastreamento/economia , Programas de Rastreamento/estatística & dados numéricos , Infecções por Parvoviridae/sangue , Infecções por Parvoviridae/diagnóstico , Infecções por Parvoviridae/prevenção & controle , Infecções por Parvoviridae/transmissão , Parvovirus B19 Humano/genética , Parvovirus B19 Humano/isolamento & purificação , Reação em Cadeia da Polimerase/economia , Segurança , Estados Unidos , Viremia/virologiaRESUMO
BACKGROUND: Nonenveloped and thermostable viruses such as parvovirus B19 (B19) can be transmitted to patients who are receiving plasma-derived coagulation factor concentrates treated by the S/D method for inactivating enveloped viruses. Therefore, it is important to develop and validate new methods for the inactivation of nonenveloped viruses. STUDY DESIGN AND METHODS: Suspensions of B19 in coagulation factor concentrates (FVIII) were irradiated with UVC light. B19 infectivity was determined by an indirect immunofluorescence assay using CFU-E, as a host cell, derived from peripheral blood CD34+ cells. The effects of catechins on B19 infectivity and on FVIII activity after UVC illumination were also examined. RESULTS: The indirect immunofluorescence assay estimated the B19 infectivity of samples containing virus copies of 10(5) to 10(11) per 10 microL to be a median tissue culture-infectious dose of 10(0.3) to 10(5.4) per 10 microL. B19 was inactivated by 3 log at 750 J per m(2) of UVC radiation and was undetectable after 1000 or 2000 J per m(2) of irradiation. However, FVIII activity decreased to 55 to 60 percent of pretreatment activity after 2000 J per m(2) of UVC radiation. This was inhibited in the presence of rutin or catechins. Epigallocatechin gallate could maintain FVIII activity at almost 100 percent of pretreatment activity after 2000 J per m(2) of UVC radiation, while B19 infectivity was decreased to undetectable levels, which resulted in >3.9 log inactivation. CONCLUSION: UVC radiation in the presence of catechins, especially epigallocatechin gallate, appears to be an effective method of increasing the viral safety of FVIII concentrates without the loss of coagulation activity.