Dataset Information

The role of supplementary environmental surveillance to complement acute flaccid paralysis surveillance for wild poliovirus in Pakistan - 2011-2013.

ABSTRACT:

Background

More than 99% of poliovirus infections are non-paralytic and therefore, not detected by acute flaccid paralysis (AFP) surveillance. Environmental surveillance (ES) can detect circulating polioviruses from sewage without relying on clinical presentation. With extensive ES and continued circulation of polioviruses, Pakistan presents a unique opportunity to quantify the impact of ES as a supplement to AFP surveillance on overall completeness and timeliness of poliovirus detection.

Methods

Genetic, geographic and temporal data were obtained for all wild poliovirus (WPV) isolates detected in Pakistan from January 2011 through December 2013. We used viral genetics to assess gaps in AFP surveillance and ES as measured by detection of 'orphan viruses' (?1.5% different in VP1 capsid nucleotide sequence). We compared preceding detection of closely related circulating isolates (?99% identity) detected by AFP surveillance or ES to determine which surveillance system first detected circulation before the presentation of each polio case.

Findings

A total of 1,127 WPV isolates were detected by AFP surveillance and ES in Pakistan from 2011-2013. AFP surveillance and ES combined exhibited fewer gaps (i.e., % orphan viruses) in detection than AFP surveillance alone (3.3% vs. 7.7%, respectively). ES detected circulation before AFP surveillance in nearly 60% of polio cases (200 of 346). For polio cases reported from provinces conducting ES, ES detected circulation nearly four months sooner on average (117.6 days) than did AFP surveillance.

Interpretation

Our findings suggest ES in Pakistan is providing earlier, more sensitive detection of wild polioviruses than AFP surveillance alone. Overall, targeted ES through strategic selection of sites has important implications in the eradication endgame strategy.

SUBMITTER: Cowger TL

PROVIDER: S-EPMC5526532 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Publications

The role of supplementary environmental surveillance to complement acute flaccid paralysis surveillance for wild poliovirus in Pakistan - 2011-2013.

Cowger Tori L TL Burns Cara C CC Sharif Salmaan S Gary Howard E HE Iber Jane J Henderson Elizabeth E Malik Farzana F Zahoor Zaidi Syed Sohail SS Shaukat Shahzad S Rehman Lubna L Pallansch Mark A MA Orenstein Walter A WA

PloS one 20170725 7

<h4>Background</h4>More than 99% of poliovirus infections are non-paralytic and therefore, not detected by acute flaccid paralysis (AFP) surveillance. Environmental surveillance (ES) can detect circulating polioviruses from sewage without relying on clinical presentation. With extensive ES and continued circulation of polioviruses, Pakistan presents a unique opportunity to quantify the impact of ES as a supplement to AFP surveillance on overall completeness and timeliness of poliovirus detection ...[more]

PMID: 28742803

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Project description:BackgroundWorld Health Organization (WHO) targets for acute flaccid paralysis (AFP) surveillance, including the notification of a minimum rate of AFP among children, are used to assess the adequacy of AFP surveillance for the detection of poliovirus infection. Sensitive surveillance for poliovirus infection in both developed and developing countries is essential to support global disease eradication efforts. We applied recently developed methods for the quantitative evaluation of disease surveillance systems to evaluate the sensitivity of AFP surveillance for poliovirus infection in Australia.MethodsA scenario tree model which accounted for administrative region, age, population immunity, the likelihood of AFP, and the probability of notification and stool sampling was used to assess the sensitivity of AFP surveillance for wild poliovirus infection among children aged less than 15 years in Australia. The analysis was based on historical surveillance data collected between 2000 and 2005. We used a surveillance time period of one month, and evaluated the ability of the surveillance system to detect poliovirus infection at a prevalence of 1 case per 100 000 persons and 1 case per million persons.ResultsThere was considerable variation in the sensitivity of AFP surveillance for poliovirus infection among Australian States and Territories. The estimated median sensitivity of AFP surveillance in Australia among children aged less than 15 years was 8.2% per month at a prevalence of 1 case per 100,000 population, and 0.9% per month at a prevalence of 1 case per million population. The probability that Australia is free from poliovirus infection given negative surveillance findings following 5 years of continuous surveillance was 96.9% at a prevalence of 1 case per 100,000 persons and 56.5% at a prevalence of 1 case per million persons.ConclusionGiven the ongoing risk of poliovirus importation prior to global eradication, long term surveillance is required to provide a high degree of confidence in freedom from poliovirus infection in Australia, particularly if a low prevalence of infection is assumed. Adherence to the WHO surveillance targets would considerably improve the sensitivity of surveillance for poliovirus infection in Australia.

Project description:Enterovirus A71 (EV-A71) is a non-polio enterovirus that currently represents a major public health concern worldwide. In Africa, only sporadic cases have been reported. Acute flaccid paralysis and environmental surveillance programs have been widely used as strategies for documenting the circulation of polio and non-polio enteroviruses. To date, little is known about the molecular epidemiology of enterovirus A71 in Africa where resources and diagnostic capacities are limited. To fill this gap in Senegal, a total of 521 non-polio enterovirus isolates collected from both acute flaccid paralysis (AFP) and environmental surveillance (ES) programs between 2013 and 2020 were screened for enterovirus A71 using real-time RT-PCR. Positive isolates were sequenced, and genomic data were analyzed using phylogeny. An overall rate of 1.72% (9/521) of the analyzed isolates tested positive for enterovirus A71. All positive isolates originated from the acute flaccid paralysis cases, and 44.4% (4/9) of them were isolated in 2016. The nine newly characterized sequences obtained in our study included eight complete polyprotein sequences and one partial sequence of the VP1 gene, all belonging to the C genogroup. Seven out of the eight complete polyprotein sequences belonged to the C2 subgenotype, while one of them grouped with previous sequences from the C1 subgenotype. The partial VP1 sequence belonged to the C1 subgenotype. Our data provide not only new insights into the recent molecular epidemiology of enterovirus A71 in Senegal but also point to the crucial need to set up specific surveillance programs targeting non-polio enteroviruses at country or regional levels in Africa for rapid identification emerging or re-emerging enteroviruses and better characterization of public health concerns causing acute flaccid paralysis in children such as enterovirus A71. To estimate the real distribution of EV-A71 in Africa, more sero-epidemiological studies should be promoted, particularly in countries where the virus has already been reported.

Project description:The Polio Endgame Strategy 2019-2023 has been developed. However, more effective and efficient surveillance activities should be conducted with the preparedness of emergence for vaccine-derived poliovirus (VDPV) or wild poliovirus (WPV). We reviewed the impact of the case-based acute flaccid paralysis (AFP) surveillance (1991 to 2018) and environmental surveillance (2011 to 2018) in polio eradication in Shandong province of China. Clinical characteristics of AFP cases and enterovirus (EV) investigation of research samples were assessed. During the period, 10,224 AFP cases were investigated, and 352 sewage samples were collected. The nonpolio AFP rate sustained at over 2.0/100,000 since 1997. Of 10,224 cases, males and young children experienced a higher risk of severe diseases, and 68.5% suffered lower limb paralysis. We collected 1,707 EVs from AFP cases, including 763 polioviruses and 944 nonpolio enteroviruses (NPEVs). No WPV was isolated since 1992. The AFP surveillance showed high sensitivity in detecting 143 vaccine-associated paralytic poliomyelitis (VAPP) cases and 6 VDPVs. For environmental surveillance, 217 (61.6%) samples were positive for poliovirus, and altogether, 838 polioviruses and 2,988 NPEVs were isolated. No WPV was isolated in environmental surveillance, although one VDPV2 was identified. Phylogenetic analysis revealed environmental surveillance had the capacity to detect a large scope of NPEVs. The case-based AFP surveillance will be indispensable for detecting VAPP cases and VDPV circulation in countries using oral polio vaccine. Environmental surveillance is advantageous in identifying EV circulation and responding to ongoing circulating VDPV outbreaks and should be expanded to complement the AFP surveillance.IMPORTANCE Interrupting wild poliovirus transmission and stopping circulating vaccine-derived poliovirus (cVDPV) outbreaks have been proposed as two global goals by the World Health Organization in the Global Polio Eradication Initiative (GPEI). This analysis, based on the 28-year acute flaccid paralysis (AFP) surveillance and 8-year environmental surveillance, provides continued high-quality surveillance performance in achieving the GPEI and detecting the circulation of enterovirus. Given the ongoing cVDPV outbreaks in the world, we present the surveillance capacity of environmental surveillance in capturing enterovirus circulation. The final poliovirus (especially VDPV) elimination has become increasingly complex, and the case-based AFP surveillance alone will lead to difficulties in early detecting dynamics of poliovirus transmission and monitoring the extent of environmental circulation. This study goes beyond previous work to provide a detailed comprehensive evaluation of the enterovirus surveillance and can be used to formulate a set of implementation plan and performance indicators for environmental surveillance.

Dataset Information

The role of supplementary environmental surveillance to complement acute flaccid paralysis surveillance for wild poliovirus in Pakistan - 2011-2013.

Background

Methods

Findings

Interpretation

Publications

The role of supplementary environmental surveillance to complement acute flaccid paralysis surveillance for wild poliovirus in Pakistan - 2011-2013.

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