title: Prevalence of asymptomatic poliovirus infection in older children and adults in northern India: analysis of contact and enhanced community surveillance, 2009.
abstract: BACKGROUND
  In 2009, enhanced poliovirus surveillance was established in polio-endemic areas of Uttar Pradesh and Bihar, India, to assess poliovirus infection in older individuals.
  
  
  METHODS
  In Uttar Pradesh, stool specimens from asymptomatic household and neighborhood contacts of patients with laboratory-confirmed polio were tested for polioviruses. In Bihar, in community-based surveillance, children and adults from 250 randomly selected households in the Kosi River area provided stool and pharyngeal swab samples that were tested for polioviruses. A descriptive analysis of surveillance data was performed.
  
  
  RESULTS
  In Uttar Pradesh, 89 of 1842 healthy contacts of case patients with polio (4.8%) were shedding wild poliovirus (WPV); 54 of 85 (63.5%) were ≥5 years of age. Shedding was significantly higher in index households than in neighborhood households (P<.05). In Bihar, 11 of 451 healthy persons (2.4%) were shedding WPV in their stool; 6 of 11 (54.5%) were ≥5 years of age. Mean viral titer was similar in older and younger children.
  
  
  CONCLUSIONS
  A high proportion of persons≥5 years of age were asymptomatically shedding polioviruses. These findings provide indirect evidence that older individuals could have contributed to community transmission of WPV in India. Polio vaccination campaigns generally target children<5 years of age. Expanding this target age group in polio-endemic areas could accelerate polio eradication.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Mach
authors.affiliation: National Polio Surveillance Unit.
authors.forename: Harish
authors.initials: H
authors.lastname: Verma
authors.affiliation: National Polio Surveillance Unit.
authors.forename: Devendra W
authors.initials: DW
authors.lastname: Khandait
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Roland W
authors.initials: RW
authors.lastname: Sutter
authors.affiliation: World Health Organization, Regional Office for South East Asia, New Delhi, India.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: O'Connor
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Pallansch
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Cochi
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Linkins
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Susan Y
authors.initials: SY
authors.lastname: Chu
authors.affiliation: World Health Organization, Geneva, Switzerland.
authors.forename: Chris
authors.initials: C
authors.lastname: Wolff
authors.affiliation: National Polio Surveillance Unit.
authors.forename: Hamid S
authors.initials: HS
authors.lastname: Jafari
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D062665:Epidemiological Monitoring; D005243:Feces / Q000821:virology; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000821:virology; D011051:Poliomyelitis / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D017955:Poliovirus / Q000302:isolation & purification*; D015995:Prevalence; D017201:Virus Shedding; D055815:Young Adult
keywords: India; community transmission; enhanced surveillance; poliomyelitis