Contribution of second stool specimen to increased sensitivity of poliovirus detection in India, 1998–2000

Abstract

Acute flaccid paralysis (AFP) surveillance data from India were analysed to examine sensitivity of poliovirus isolation from stool specimens and the added sensitivity obtained from collection of a second stool specimen. Analysis was restricted to Indian AFP cases, 1998-2000, with two adequate stool specimens. The proportion of cases confirmed with wild poliovirus isolation by the second specimen only was calculated, regardless of specimen quality. Overall specimen sensitivity (1998-2000) was 81% using the first specimen, 78% using the second, and 96% using both. Sensitivity increased from 1998 to 2000, with slightly higher sensitivity each year for the first specimen. The second specimen increased sensitivity by 15% overall and contributed more when the first specimen was collected late or was in poor condition. As wild poliovirus disappears, increased sensitivity provided by a second stool specimen may reduce the risk of missing circulating virus.

Surveillance during an era of rapidly changing poliovirus epidemiology in India: the role of one vs. two stool specimens in poliovirus detection, 2000–2010

“…The percentage of cases identified only by the second sample (7•2%) is similar to findings of previous studies in Latin America (8%) [4] and from the USA (10%) [8] but is lower than estimates reported previously from India (21%) [15] and the Western Pacific region (31%) [16]. The lower estimate in our analysis compared to a previous analysis of India's AFP surveillance system [15] could be due to improvements in the collection, storage and transport of specimens, as well as improved laboratory performance. Indeed, by 2000, both specimen sensitivity and the percentage of cases identified by the second stool sample (12%) approached comparable levels to the current analysis from 2000 to 2010.…”

Contribution of Contact Sampling in Increasing Sensitivity of Poliovirus Detection During A Polio Outbreak—Somalia, 2013

“…We estimated the added contribution of each contact specimen using a method similar to that described by Gary et al [ 17 ], which derives maximum-likelihood estimates for specimen sensitivities of each stool specimen. This method has previously been used to assess sensitivities of the first and second stool specimens collected from AFP case-patients, by assuming each stool specimen to be independent of each other; therefore, each stool specimen functions as the gold standard estimate for the other specimen [ 18 , 19 ].…”

Poliovirus nonpermissive CD155 knockout cells derived from RD cell line for handling poliovirus potentially infectious materials in virology laboratories

“…This dilemma was resolved when L20B cells became available to the global polio laboratory network. 15 L20B cells do not support the growth of most NPEV types. Thus, simplifying poliovirus isolation from stool samples of AFP cases.…”

“…Identifying polioviruses from mixtures of polio and non‐poliovirus isolates was time‐consuming if not very difficult. This dilemma was resolved when L20B cells became available to the global polio laboratory network 15 . L20B cells do not support the growth of most NPEV types.…”