Surveillance of poliomyelitis in Northern Italy: Results of acute flaccid paralysis surveillance and environmental surveillance, 2012–2015

Abstract

Although in the last years poliovirus (PV) transmission has been reported at the lowest levels ever recorded, the spread of virus from endemic countries endures; the high levels of immigration flows across the Mediterranean Sea jeopardize Italy for PV reintroduction. The World Health Organization (WHO) strategic plan for global poliomyelitis (polio) eradication indicates the nationwide surveillance of Acute Flaccid Paralysis (AFP) as the gold standard for detecting cases of polio. In addition, the Environmental Surveillance (ES), seeking the presence of PV and Non-Polio Enterovirus (NPEV) in sewage, is recognized as a powerful tool to confirm PV circulation in absence of AFP cases, especially in polio-free countries. Here we report the results of AFP surveillance (AFPS) and ES in Lombardy (Northern Italy) from 2012 to 2015.Forty-eight AFP cases were identified during the study period. No AFP case was caused by PV infection. NPEVs were identified in 6.3% (3/48) of AFP cases. The annual AFP incidence rate was 0.87/100 0 000 children <15 y in 2012, 1.42/100 0 000 in 2013, 1.02/100 0 000 in 2014, and 0.47/100 0 000 in 2015; according to WHO indicators, the sensitivity of AFPS was adequate in 2013 and 2014. Completeness of case investigation raised progressively during the study period to achieve the WHO standards in 2014 (92.3%) and 2015 (100%). Completeness of follow-up increased from 72.7% in 2012 to 100% in 2014.In the framework of the ES conducted in Milan, 268 wastewater samples were collected from 2012 to 2015 and no PVs were isolated. In contrast, NPEVs were detected in 65.3% (175/268) of samples. All NPEVs characterized belonged to enterovirus species B: echovirus type 11, 6 and 3 were the most frequently detected viruses, representing 29.1% (41/141), 20.6% (29/141) and 9.2% (13/141) of genotyped NPEVs, respectively.Keeping strong and encouraging both AFPS and ES is crucial to ensure that PV will not return unnoticed in Italy -as well as in other polio-free countries -and, as a final point, to achieve the global polio eradication goal.

Environmental Surveillance for Poliovirus and Other Enteroviruses: Long-Term Experience in Moscow, Russian Federation, 2004–2017

“…Since vaccination against poliomyelitis with OPV is carried out in Russia in accordance with the National Vaccination Schedule throughout the year, which excludes the effect of vaccination campaigns on the frequency of EV release, this suggests that the Moscow region is characterized by pronounced summer–autumn seasonality of NPEV circulation among the population. The high prevalence of the EV-B species among the NPEV viruses is consistent with the results of studies carried out in Europe [31,32,33,34,37,45] and seems to reflect the epidemiology of NPEV in the region. Viruses E7, E11 and E19 were isolated mainly from wastewater, which indicates the silent circulation of these types in the population and their low pathogenicity.…”

Haiti Poliovirus Environmental Surveillance

“…The bias for the detection of echoviruses and other species B enteroviruses was most likely due to the RD cell line being used as part of the WHO virus isolation algorithm. 37 Environmental surveillance studies in Northern Italy and North India isolated mainly Enterovirus B types (e.g., Coxsackie B viruses and echoviruses), 38,39 whereas studies that included an additional cell line beyond RD cells (e.g., HEp2 and HT29) isolated a wider variety of enteroviruses. 16,40 The detection of human NPEVs confirms that the selected sites are impacted by human sewage.…”

Emerging Non-Polio Enteroviruses recognized in the framework of the Acute Flaccid Paralyses (AFP) surveillance system in Northern Italy, 2016–2018

“…Despite not achieving the indicators' goals, overall, the AFPS results were adequate in Lombardy in terms of data quality and timeliness, completeness of case investigation (>80%), and completeness of clinical follow-ups. Also, performances in Lombardy showed an overall improvement of AFPS compared to the results obtained from 1997 to 2011 (Pellegrinelli et al, 2015) in the same surveyed area and those reached in other Italian regions (Fiore et al, 1999;Patti et al, 2000;Angelillo et al, 2001;D'Errico et al, 2008;Pellegrinelli et al, 2017aPellegrinelli et al, , 2017bPalandri et al, 2020).…”

“…For rapid virus identification, RNA was extracted from stool suspension, respiratory samples, and the lysate of cell cultures that showed a cytopathic effect (CPE), and a specific 5 0 noncoding region (nucleotide [nt.] 179-575) of EVs was amplified by an inhouse one-step real-time RT-PCR assay (Pellegrinelli et al, 2017a(Pellegrinelli et al, , 2017b.…”