Response This is, of course, a very interesting question and difficult to deduce from the phylogenetic tree of a single protein without molecular clock, as in our case. However, this and similar questions have already been analyzed to quite some detail for the existing strains. The current knowledge of the scenario for H1N1 is that around the late 1970s to early 1980s, a human-avian reassortant virus started to be detected in European pigs as host (PMID: 8091678). Then, this avian-like swine flu started to move from the European continent to the UK in the early 90s (PMID: 9049404). More reassortments and emergence of the N2 subtype that quickly spread is also well documented. This phylogenetic analysis plugs the new H1N1 strain into the already known clusterings among the NA subtypes and within the N1 family. Development of TaqMan(® )MGB fluorescent real-time PCR assay for the detection of anatid herpesvirus 1 BACKGROUND: Anatid herpesvirus 1 (AHV-1) is an alphaherpesvirus associated with latent infection and mortality in ducks and geese and is currently affecting the world-wide waterfowl production severely. Here we describe a fluorescent quantitative real-time PCR (FQ-PCR) method developed for fast measurement of AHV-1 DNA based on TaqMan MGB technology. RESULTS: The detection limit of the assay was 1 × 10(1 )standard DNA copies, with a sensitivity of 2 logs higher than that of the conventional gel-based PCR assay targeting the same gene. The real-time PCR was reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. CONCLUSION: The high sensitivity, specificity, simplicity and reproducibility of the AHV-1 fluorogenic PCR assay, combined with its wide dynamic range and high throughput, make this method suitable for a broad spectrum of AHV-1 etiologically related application. China is currently holding the largest waterfowl population in the world and its waterfowl production industry has been characterized by an increasing expansion and rapid development during the past decades [1] . However, infectious diseases represent the biggest obstacle to successful development of this business. Anatid herpesvirus 1 (AHV-1) infection alternatively known as duck virus enteritis (DVE), or duck plague (DP) [2] , is one of the most widespread and devastating diseases of waterfowls in the family Anatidae and has severally affected the waterfowl industry since the early 1900s because relatively high mortality could be observed and a wide host range including domestic [3] and wild ducks [4, 5] , geese and swans of all species as well as other birds like coots are susceptible. Furthermore, serious carcass condemnations and decreased egg production were also observed in affected waterfowls. Like other herpesvirus-induced diseases, AHV-1 infection has latent form and the virus can be persistently shed by birds that recover from the disease [6] . This complicates the control of the disease, particularly under small-holder farming conditions prevalent in China.