Differentiation, emergence and re-emergence of viral pathogens: past, present, future / Zróznicowanie, pojawianie sie i powracanie patogenów wirusowych: przeszlosc, terazniejszosc, przyszlosc.

Viruses and viral diseases have been the subject of interest for science and some of our greatest challenges and achievements are in the field of virology. Cases of emerging and re-emerging infections have posed problems and sometimes enormous public health challenges. Despite significant advances in understanding pathogen biology, the molecular mechanisms of pathogenesis, breakthroughs in the prevention of these infections, and their impact on public health and the global economy, the emergence of new pandemic viruses remains unclear. This review article presents the current state of knowledge on newly emerging viral infections in the world, including recent SARS-CoV-2, MERS, ZIKV epidemics and discussing their possible origins, evolution, natural reservoir, mechanisms of adaptation to the human and potential risk factors.

Isolation of Sabin-like Polioviruses from Sewage in Poland.

As a complement to the active search for cases of acute flaccid paralysis, environmental sampling was conducted from January to December 2011, to test for any putative polio revertants and recombinants in sewage. A total of 165 environmental samples were obtained and analyzed for the presence of polioviruses by use of cell culture (L20B, RD and Caco-2) followed by neutralization and reverse-transcription polymerase chain reaction. Out of the 31 CPE positive samples, 26 contained one and 5 two different serotypes, yielding a total of 36 PVs. The microneutralization test revealed the presence of 7, 10 and 19 strains belonging to poliovirus serotype 1, 2 and 3, respectively. The genomic variability of 36 poliovirus strains was examined by the restriction fragment length polymorphism assay (RFLP). By combined analyses of two distant, polymorphic segments of the viral genome, one situated in the capsid protein VP1 coding region and the other in the 3D-polymerase coding region, we screened for the putative poliovirus revertants and recombinants. All detected PVs were classified as vaccine strains on the basis of RFLP-VP1 test. None of wild-type PVs or vaccine derived polioviruses were detected. RFLP assay also revealed the presence of 11 recombinants in 3D-polymerase coding region. Nine isolates appeared to be S3/S2, one S3/S1 and S1/S2 recombinant in analyzed 3Dpol region. This study revealed, through environmental monitoring, the introduction of SL PVs into the population associated with the routine use of OPV in Poland before the April 2016. Our findings demonstrate the usefulness of environmental surveillance in the overall polio eradication program.

Genetic characterization of enterovirus A71 isolates from severe neurological cases in Poland.

The aim of this study was to report a minor outbreak of enterovirus A71 (EV-A71) infection in Poland and characterize isolates from cases of severe neurological infection detected in 2013 and 2016. Phylogenetic analysis revealed that Polish strains belonged to the C genogroup: C1, C2, and C4. Severe neurological manifestations as encephalitis or acute flaccid paralysis (AFP), were associated with all detected subgenogroups. The C2 subgenogroup was associated with the outbreak in Gdansk, with serious cases of AFP, myelitis, cerebellitis, encephalitis, but also with mild, sporadic cases of aseptic meningitis, in other Polish cities. Data from the study established relationships of EV-A71 from Poland with previously characterized strains and confirmed the importance of high quality enterovirus surveillance with international reach.

Detection of Polioviruses in Sewage Using Cell Culture and Molecular Methods.

The work presented here demonstrates the utility of a two-step algorithm for environmental poliovirus surveillance based on: preselection of sewage samples tested for the presence of enteroviral genetic material-RT-PCR assay and detection of infectious viruses by cell culture technique (L20B for polioviruses and RD for polio and other non-polio enteroviruses). RD and L20B cell lines were tested to determine their sensitivity for isolation of viruses from environmental samples (sewage). Finally, we wanted to determine if sewage concentration affects the results obtained for RT-PCR and cell cultures.

Genetic Characterization of Human Enteroviruses Associated with Hand, Foot and Mouth Diseases in Poland, 2013-2016.

The objective of the present study was to describe the molecular characteristics of enteroviruses associated with hand, food, and mouth disease (HFMD) in Poland. Clinical material from HFMD cases, that occurred during 2013-2016 were examined. It has been showed that coxsackievirus A6 (CVA6), CVA10 and CVA16 were circulating in the country. Phylogenetic analysis showed that Polish CVA6 strains were divided into two distinct clusters suggesting two independent introductions. This is the first report of CVA6 infections associated with HFMD in Poland. These results emphasize the need for continuous monitoring of HFMD and facilitation of the diagnosis using molecular approaches.

Molecular characterization of environmental and clinical echovirus 6 isolates from Poland, 2006-2014.

The aim of this study was to investigate the genetic variability of echovirus 6 (E6) isolates from environmental samples and clinical cases of aseptic meningitis from 2006 to 2014. The analysis of the VP1 region showed the extensive diversity (up to 18.8%) and revealed that E6 circulating in Poland belong to four groups. Environmental strains clustered in three groups excepting the 2012 outbreak group, which shows the sudden introduction of new epidemic variant with Asiatic origin. Data from the study established relationships of E6 from Poland with previously characterized strains and confirmed the importance of both clinical and environmental surveillance. J. Med. Virol. 89:936-940, 2017. © 2016 Wiley Periodicals, Inc.

Molecular characterization of echovirus 30 isolates from Poland, 1995-2015.

Echovirus 30 (E30) is one of the most frequently identified enterovirus and a major cause of meningitis in children and adults. To investigate the genetic variability and relationship of E30 isolated from specimens of aseptic meningitis cases that occurred in Poland over a period of 20 years, sequences of VP1 gene were determined and genetic analysis was performed. From 1995 to 2015, 124 E30 were isolated using RD cells, and 58 isolates were sequenced and characterized by phylogenetic analysis of partial VP1 region (793 nt). In general, nucleotide sequence divergence in pairwise comparisons among Polish E30 isolates ranged from 0.0 to 15.0 %. The phylogenetic analysis revealed that E30 circulating in Poland since 1995 belong to two unique groups: Group I, characterized by high divergence (up to 13.1 %), segregated in four subgroups, and showed strong temporal circulation of E30. Group II, detected in Poland in 2013-2014, was closely correlated with two meningitis outbreaks and formed a separate genetically homogeneous group. Phylogenetic analysis revealed that strains from Poland had the closest genetic relationship with not only the isolates previously identified in Europe (Belarus, France, Germany, Italy, Russia) but also those in other parts of the world (Australia, China). Sequences of outbreak isolates were grouped in group II together with those from Russia and China isolated during 2010-2013. The identification of five distinct viral lineages during 1995-2015 confirmed the high E30 genetic diversity which may be an essential precondition for the emergence of new strains responsible for further potential aseptic meningitis outbreaks.

Enteroviruses Associated with Aseptic Meningitis in Poland, 2011-2014.

A 4-year study (2011-2014) of patients with meningitis was performed. Out of the 686 cerebrospinal fluid samples, 465 (67.8%) were posi-tive for eneteroviruses using RT-PCR and out of 334 clinical samples, 216 (64.7%) were positive for enteroviruses using cell culture methods. The highest detection rate was observed in the summer and autumn. In total, 185 enteroviruses were identified by using neutralization test. Echovirus 6 and 30 were the most common (41.7% and 37.5% respectively). The highest frequency of neurological infections (32.7%) occurred in children aged 5-9 years, mostly males (63.9%).

Enteroviruses Associated with Aseptic Meningitis in Poland, 2011­2014.

A 4-year study (2011­2014) of patients with meningitis was performed. Out of the 686 cerebrospinal fluid samples, 465 (67.8%) were positive for eneteroviruses using RT-PCR and out of 334 clinical samples, 216 (64.7%) were positive for enteroviruses using cell culture methods. The highest detection rate was observed in the summer and autumn. In total, 185 enteroviruses were identified by using neutralization test. Echovirus 6 and 30 were the most common (41.7% and 37.5% respectively). The highest frequency of neurological infections (32.7%) occurred in children aged 5­9 years, mostly males (63.9%).