Contribution of Environmental Surveillance Toward Interruption of Poliovirus Transmission in Nigeria, 2012–2015

Abstract

Background. Cases of paralysis caused by poliovirus have decreased by >99% since the 1988 World Health Assembly's resolution to eradicate polio. The World Health Organization identified environmental surveillance (ES) of poliovirus in the poliomyelitis eradication strategic plan as an activity that can complement acute flaccid paralysis (AFP) surveillance. This article summarizes key public health interventions that followed the isolation of polioviruses from ES between 2012 and 2015.Methods. The grap method was used to collect 1.75 L of raw flowing sewage every 2–4 weeks. Once collected, samples were shipped at 4°C to a polio laboratory for concentration. ES data were then used to guide program implementation.Results. From 2012 to 2015, ES reported 97 circulating vaccine-derived polioviruses (cVDPV2) and 14 wild polioviruses. In 2014 alone, 54 cVDPV type 2 cases and 1 WPV type 1 case were reported. In Sokoto State, 58 cases of AFP were found from a search of 9426 households. A total of 2 252 059 inactivated polio vaccine and 2 460 124 oral polio vaccine doses were administered to children aged <5 year in Borno and Yobe states.Conclusions. This article is among the first from Africa that relates ES findings to key public health interventions (mass immunization campaigns, inactivated polio vaccine introduction, and strengthening of AFP surveillance) that have contributed to the interruption of poliovirus transmission in Nigeria.

Dynamics affecting the risk of silent circulation when oral polio vaccination is stopped

“…ES has already been used to discover long local SC of polio in Pakistan ( Alam et al, 2016 ). In Nigeria ES has demonstrated its capacity to guide public health actions ( Johnson Muluh et al, 2016 ). It detected a cVDPV2 that stimulated a special vaccination program after OPV2 use had been ceased in the rest of the world ( Etsano et al, 2016 ).…”

“…That will help locate ES where it will be most informative. Currently sites are being located where the most problems in eliminating polio cases have been experienced ( Johnson Muluh et al, 2016 ). But one implication of older age groups sustaining prolonged low-level SC is that populations not exposed to OPV or WPV from kids might have more waned immunity and thus be more likely to sustain reinfection transmission chains given high transmission conditions.…”

A Review of the Most Commonly Used Methods for Sample Collection in Environmental Surveillance of Poliovirus

“…The 2-phase separation method has been extensively used during PV ES campaigns and has been very successful at detecting WPV [ 32–36 ], Sabin-like PV strains [ 17 , 34 , 36–42 ], VDPV [ 17 , 18 , 41 ], and other PV strains [ 35 ].…”

Could Water and Sanitation Shortfalls Exacerbate SARS-CoV-2 Transmission Risks?

“…Of six major northern Nigeria cities conducting polio virus environmental surveillance, only Abuja operates a sewage plant. 10 In Lagos, there are multiple sewage treatment plants, but their performance is suboptimal, and they therefore pose a risk of enteric pathogen transmission to surrounding areas. 11 , 12 Sewage handling capacity has not grown in tandem with the explosive and continued growth of this megacity so that coverage does not extend to all residents.…”

“…13 As a result, fecal matter can be deposited into the open environment, pour from toilets unconnected to sewerage into surface water, or be buried underground in soakaways and pits from where, if these receptacles are not adequately protected, it can seep into shallow wells used for irrigation, drinking, and household purposes. 10 , 13 – 15…”