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Abstract: In 2008, Canada designed and implemented the Canadian Notifiable Avian Influenza Surveillance System (CanNAISS) with six surveillance activities in a phased-in approach. CanNAISS was a surveillance system because it had more than one surveillance activity or component in 2008: passive surveillance; pre-slaughter surveillance; and voluntary enhanced notifiable avian influenza surveillance. Our objectives were to give a short overview of two active surveillance components in CanNAISS; describe the CanNAISS scenario tree model and its application to estimation of probability of populations being free of NAI virus infection and sample size determination. Our data from the pre-slaughter surveillance component included diagnostic test results from 6296 serum samples representing 601 commercial chicken and turkey farms collected from 25 August 2008 to 29 January 2009. In addition, we included data from a sub-population of farms with high biosecurity standards: 36,164 samples from 55 farms sampled repeatedly over the 24 months study period from January 2007 to December 2008. All submissions were negative for Notifiable Avian Influenza (NAI) virus infection. We developed the CanNAISS scenario tree model, so that it will estimate the surveillance component sensitivity and the probability of a population being free of NAI at the 0.01 farm-level and 0.3 within-farm-level prevalences. We propose that a general model, such as the CanNAISS scenario tree model, may have a broader application than more detailed models that require disease specific input parameters, such as relative risk estimates. [Copyright &y& Elsevier]

Please cite this paper as: Morens and Taubenberger (2010) An avian outbreak associated with panzootic equine influenza in 1872: an early example of highly pathogenic avian influenza? Influenza and Other Respiratory Viruses 4(6), 373-377. An explosive fatal epizootic in poultry, prairie chickens, turkeys, ducks and geese, occurred over much of the populated United States between 15 November and 15 December 1872. To our knowledge the scientific literature contains no mention of the nationwide 1872 poultry outbreak. To understand avian influenza in a historical context. The epizootic progressed in temporal-geographic association with a well-reported panzootic of equine influenza that had begun in Canada during the last few days of September 1872. The 1872 avian epizootic was universally attributed at the time to equine influenza, a disease then of unknown etiology but widely believed to be caused by the same transmissible respiratory agent that caused human influenza. Another microbial agent could have caused the avian outbreak; however, its strong temporal and geographic association with the equine panzootic, and its clinical and epidemiologic features, are most consistent with highly pathogenic avian influenza. The avian epizootic could thus have been an early instance of highly pathogenic avian influenza. [ABSTRACT FROM AUTHOR]

Influenza A viruses infecting poultry can be divided into 2 groups. The extremely virulent viruses cause highly pathogenic avian influenza (HPAI), with flock mortality as great as 100%. These viruses have been restricted to subtypes H5 and H7, although not all H5 and H7 viruses cause HPAI. All other viruses cause a milder, primarily respiratory, disease (LPAI) unless exacerbated. Until recently, HPAI viruses were rarely isolated from wild birds, but for LPAI viruses, extremely great isolation rates have been recorded in surveillance studies. Influenza viruses may infect, all types of domestic or captive birds in all areas of the world, with the frequency with which primary infections occur in any type of bird usually depending on the degree of contact of the bird with feral birds. Secondary spread is usually associated with human involvement, either by bird or bird product movement, or by transferring infective feces from infected to susceptible birds, but potentially wild birds could be involved. In recent years, the frequency of HPAI outbreaks appears to have increased, and there have been particularly costly out- breaks of HPAI in densely populated poultry areas in Italy, the Netherlands, and Canada. In each, millions of birds were slaughtered to bring the outbreaks under control. Since the 1990s, avian influenza infections attributable to 2 subtypes have been widespread in poultry across a large area of the world. The LPAI H9N2 virus appears to have spread across the whole of Asia in that time and has become endemic in poultry in many of the affected countries. However, these outbreaks have tended to be overshadowed by the H5N1 HPAI virus, which, although initially isolated in China, has now spread in poultry, wild birds, or both throughout Asia and into Europe and Africa, resulting in the death or culling of hundreds of millions of poultry and posing a significant zoonotic threat. To date, control methods seem to have been unsuccessful on the larger scale, and HPAI H5N1 outbreaks continue to be reported. [ABSTRACT FROM AUTHOR]

Five hundred and seventy-three clinical submissions with fowl adenovirus (FAdV) involvement were examined to investigate the association of different types of FAdV with clinical problems related to FAdV infection. Samples were received from 2000 to 2006 and originated from seven Canadian provinces. Four hundred and eighty-seven submissions were inclusion body hepatitis (IBH) related, while 86 were not IBH related. Viruses isolated from 287 samples were further analysed by hexon gene loop 1 sequencing. Twenty-seven genotyped FAdVs were from Alberta, 20 from British Columbia, 16 from Manitoba, one from Nova Scotia, 82 from Ontario, 64 from Quebec and 77 from Saskatchewan. Two hundred and forty-six analysed FAdVs were from IBH cases, confirmed by liver histopathology, by FAdV isolation from the liver, or both. Based on hexon gene loop 1 sequencing analysis, FAdVs associated with IBH outbreaks were genetically related to FAdV02 (nine isolates, 99.4%), FAdV08a (100 isolates, 99.4% to 100%) and FAdV11 (98 isolates, 99.4% to 100%). Thirty-nine viruses were 93.7% to 94.3% identical to FAdV07 strain x11a, but the genetic and immunogenic properties of this strain require further investigation. In IBH cases, the co-infection rates for infectious bursal disease virus, infectious bronchitis virus, reoviruses and Newcastle disease virus were 3.47%, 1.04%, 6.25% and 0.69%, respectively. Forty-one genotyped FAdVs were from "non-IBH" cases. Viruses isolated from non-IBH cases consisted of 22 FAdV01, 15 FAdV11, two FAdV08a and one each of FAdV02 and FAdV04 viruses. Co-infection rates in non-IBH submissions were 50.00% for infectious bursal disease virus, 40.70% for infectious bronchitis virus, 27.91% for reoviruses and 1.16% for Newcastle disease virus. [ABSTRACT FROM AUTHOR]

The article reports on the elevated resistance of main flu virus in the U.S. and Canada to Tamiflu or oseltamivir, based on the statement of the World Health Organization (WHO). However, the WHO did not change its recommendation of Tamiflue for bird flu patients because the agency believes the efficiency of the drugs against the virus. The U.S. Centers for Disease Control and Prevention reveals that the prevalence of virus resistance to Tamiflu is only 5%. Meanwhile, WHO spokeswoman Sari Setiogi discloses that only 8 out of 81 samples have resistance against the drug.

Reports on the move of the Canadian government to order for a mass cull of chickens in the country. Discovery of the avian flu among chickens in some areas of the country; Effects of the disease on humans; Move of the European Union and other countries to ban imports of chicken from Canada.

Reports on the efforts of the Canadian government to eradicate an outbreak of bird influenza by ordering the slaughter of about 19 million birds. Confirmation by the World Health Organization of two human cases of avian influenza A in British Columbia; Concerns of public health officials in Canada; Way that viruses of low pathogenicity can, after circulation for sometimes short periods in a poultry population, migrate into highly pathogenic viruses; Development of a seed vaccine for the avian flu virus, in case the virus turns into a serious health concern.