Assessing the role of contact tracing in a suspected H7N2 influenza A outbreak in humans in Wales

BMC Infectious Diseases

Research Article

Cerian Webb¹  Ken TD Eames²  Josie Smith³  J Mark F Temple³  Roland Salmon³  Kathrin Thomas³ 

[1] Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, UK;London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK;National Public Health Service for Wales (now Public Health Wales), Temple of Peace and Health, CF10 3NW, Cardiff, UK;

关键词: Influenza;    Avian Influenza;    Oseltamivir;    Avian Influenza Virus;    Public Health Service;   

DOI  :  10.1186/1471-2334-10-141

 received in 2009-03-10, accepted in 2010-05-28,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe detailed analysis of an outbreak database has been undertaken to examine the role of contact tracing in controlling an outbreak of possible avian influenza in humans. The outbreak, initiating from the purchase of infected domestic poultry, occurred in North Wales during May and June 2007. During this outbreak, extensive contact tracing was carried out. Following contact tracing, cases and contacts believed to be at risk of infection were given treatment/prophylaxis.MethodsWe analyse the database of cases and their contacts identified for the purposes of contact tracing in relation to both the contact tracing burden and effectiveness. We investigate the distribution of numbers of contacts identified, and use network structure to explore the speed with which treatment/prophylaxis was made available and to estimate the risk of transmission in different settings.ResultsFourteen cases of suspected H7N2 influenza A in humans were associated with a confirmed outbreak among poultry in May-June 2007. The contact tracing dataset consisted of 254 individuals (cases and contacts, of both poultry and humans) who were linked through a network of social contacts. Of these, 102 individuals were given treatment or prophylaxis. Considerable differences between individuals' contact patterns were observed. Home and workplace encounters were more likely to result in transmission than encounters in other settings. After an initial delay, while the outbreak proceeded undetected, contact tracing rapidly caught up with the cases and was effective in reducing the time between onset of symptoms and treatment/prophylaxis.ConclusionsContact tracing was used to link together the individuals involved in this outbreak in a social network, allowing the identification of the most likely paths of transmission and the risks of different types of interactions to be assessed. The outbreak highlights the substantial time and cost involved in contact tracing, even for an outbreak affecting few individuals. However, when sufficient resources are available, contact tracing enables cases to be identified before they result in further transmission and thus possibly assists in preventing an outbreak of a novel virus.

【 授权许可】

CC BY   
© Eames et al; licensee BioMed Central Ltd. 2010