title: Evaluating a surveillance system: live-bird market surveillance for highly pathogenic avian influenza, a case study.
abstract: BACKGROUND
  Highly pathogenic avian influenza H5N1 was first reported in poultry in Nigeria in February 2006. The only human case that occurred was linked to contact with poultry in a live bird market (LBM). LBM surveillance was instituted to assess the degree of threat of human exposure to H5N1. The key indicator was detection of H5N1 in LBMs. We evaluated the surveillance system to assess its operations and attributes.
  
  
  METHODS
  We used the US Centers for Disease Control and Prevention (CDC) updated guidelines for evaluating public health surveillance systems. We reviewed and analyzed passive surveillance data for HPAI (January 2006-March 2009) from the Avian Influenza National Reference Laboratory, and live bird market surveillance data from the Food and Agriculture Organization of the United Nations, Nigeria. We interviewed key stakeholders and reviewed reports of live bird market surveillance to obtain additional information on the operations of the system. We assessed the key system attributes.
  
  
  RESULTS
  A total of 299 cases occurred in 25 (72%) states and the Federal Capital Territory (FCT). The system detected HPAI H5N1 virus in 7 (9.5%) LBMs; 2 (29%) of which were from 2 (18.2%) states with no previous case. A total of 17,852 (91.5%) of samples arrived at the laboratory within 24 hours but laboratory analysis took over 7 days. The sensitivity and positive predictive value (PPV) were 15.4% and 66.7% respectively.
  
  
  CONCLUSIONS
  The system is useful, flexible, complex and not timely, but appears to be meeting its objectives. The isolation of HPAI H5N1 virus in some of these markets is an indication that the markets are possible reservoirs of the virus in Nigeria. We recommend that the Federal Government of Nigeria should dedicate more funds for surveillance for HPAI as this will aid early warning and reduce the risk of a pandemic.
authors.affiliation: Nigeria Field Epidemiology and Laboratory Training Program, Nigeria.
authors.forename: Ndadilnasiya Endie
authors.initials: NE
authors.lastname: Waziri
authors.affiliation: Nigeria Field Epidemiology and Laboratory Training Program, Nigeria.
authors.forename: Patrick
authors.initials: P
authors.lastname: Nguku
authors.affiliation: Nigeria Field Epidemiology and Laboratory Training Program, Nigeria.
authors.forename: Adebola
authors.initials: A
authors.lastname: Olayinka
authors.affiliation: Department of Epidemiology, Medical Statistics and Environmental Health, University of Ibadan, Nigeria.
authors.forename: Ike
authors.initials: I
authors.lastname: Ajayi
authors.affiliation: Department of Veterinary Public Health, Ahmadu Bello University, Zaria, Nigeria.
authors.forename: Junaidu
authors.initials: J
authors.lastname: Kabir
authors.affiliation: Department of Veterinary Public Health, Ahmadu Bello University, Zaria, Nigeria.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Okolocha
authors.affiliation: ECTAD Unit, Food and Agriculture Organization, Bangladesh.
authors.forename: Tesfai
authors.initials: T
authors.lastname: Tseggai
authors.affiliation: National Veterinary Research Institute, Vom, Nigeria.
authors.forename: Tony
authors.initials: T
authors.lastname: Joannis
authors.affiliation: National Veterinary Research Institute, Vom, Nigeria.
authors.forename: Phillip
authors.initials: P
authors.lastname: Okewole
authors.affiliation: National Veterinary Research Institute, Vom, Nigeria.
authors.forename: Peterside
authors.initials: P
authors.lastname: Kumbish
authors.affiliation: National Veterinary Research Institute, Vom, Nigeria.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Ahmed
authors.affiliation: National Veterinary Research Institute, Vom, Nigeria.
authors.forename: Lami
authors.initials: L
authors.lastname: Lombin
authors.affiliation: Global Public Health Solutions, Decatur GA, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Nsubuga
mesh_terms: D000818:Animals; D003132:Commerce; D004197:Disease Reservoirs; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology*; D007753:Laboratories / Q000706:statistics & numerical data; D009549:Nigeria / Q000453:epidemiology; D011159:Population Surveillance; D011200:Poultry / Q000821:virology*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D011795:Surveys and Questionnaires; D013997:Time Factors
keywords: Live bird market; Nigeria; highly pathogenic avian influenza; surveillance