Influenza

Test codes:

A0001 - Rapid antigen test for avian influenza.  This assay detects but does not distinguish most known strains of influenza A viruses, including H5N1, H5N2, H1N1, H2N2, H3N8, H4N6, H7N7, H8N4 and H9N2.

S0077 - This assay detects but does not differentiate most known strains of influenza A viruses, including H5N1, H5N2, H1N1, H2N2, H3N8, H4N6, H7N7, H8N4 and H9N2.
S0077 is included on P0019 - Canine Respiratory Panel and on P0020 - Feline Respiratory Panel

Influenza is a severe acute upper respiratory infection, and typical symptoms include pyrexia, dyspnea, anorexia and coughing.

Several different subtypes and strains of influenza viruses infect humans, swine, birds, horses, cats, dogs and other animals. Among these different strains, the avian influenza viruses have been the major concern. The natural reservoir for these viruses is wild birds, and birds are only susceptible to influenza A viruses.

There are three prominent subtypes of avian influenza A virus. They are classified by the hemagglutinin proteins on their surfaces: H5, H7, and H9. These viruses can be further divided in “low pathogenic avian influenza (LPAI)” and “high pathogenic avian influenza (HPAI)” forms, depending on the severity of disease they cause in birds.

Genetic differences in influenza viruses that typically infect birds and other animals, such as cats and dogs, exist that impede cross-species infection. However, a study published in September 2004 demonstrated that domestic cats can become infected with the H5N1 virus and are capable of transmitting the virus to other cats (http://www.avma.org/public_health/influenza/avian_faq.asp; http://www.cdc.gov/flu/avian/gen-info/qa.htm ). In February 2006, authorities in Germany reported that a domestic cat had died from H5N1 avian influenza. That cat lived in the northern island of Ruegen, where more than 100 wild birds are believed to have died of the disease, and it likely contracted the disease by eating one of those infected birds. In March 2006, three cats in Austria were confirmed to be ill with the H5N1 virus. These cats were among 170 living in an animal shelter where the disease had been detected in chickens a month earlier. Prior to confirmation of these feline cases, there had been anecdotal reports of H5N1 infection in domestic cats in southeast Asia and Iraq.

Large cats kept in captivity can be infected with avian influenza as well. In December 2003, two tigers and two leopards that were fed fresh chicken carcasses from a local slaughterhouse died at a zoo in Thailand. Avian influenza virus H5N1 was identified in their tissue samples. In February and March 2004, the virus was detected in a clouded leopard and white tiger, respectively, both of which died in a zoo near Bangkok. In October 2004, 147 of 441 captive tigers in a zoo in Thailand died or were euthanatized as a result of infection after being fed raw chicken carcasses. Results of a subsequent investigation suggested that at least some tiger-to-tiger transmission occurred in that facility.

Dogs are not usually susceptible to avian influenza viruses; however, an unpublished study carried out in 2005 by the National Institute of Animal Health in Bangkok indicated that, while dogs could be infected with the virus, no associated disease was detected.

Due to the airborne nature of the disease, infection of one animal can quickly spread to other animals and humans. Rapid and affordable testing of suspected influenza cases is thus essential to control the spreading of the disease. If the result of the rapid immunoassay is negative but the animal exhibits symptoms of respiratory infection, Zoologix also offers reflex PCR testing of the same sample with much higher sensitivity, and for a broader range of respiratory pathogens. This testing strategy eliminates the delay and cost involved in redrawing and shipping repeat samples.

Utilities:

• Confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of influenza virus
• Ensure that animal populations are free of influenza
• Early prevention of spread of this virus
• Minimize personnel exposure to this virus

References:
Daly, J. M., Lai, A.C.K., Binns, M.M., Chambers, T.M., Barrandeguy, M. and Mumford, J.A. (1996) Antigenic and genetic evolution of equine H3N8 influenza A viruses. J. Gen. Virol. 77:661-671.
Mumford, J. A., and Wood, J.M. (1993) WHO/OIE meeting: consultation on newly emerging strains of equine influenza. Vaccine 11:1172-1175.
Office International des Epizooties (OIE) (2000) Equine influenza, p. 546-557. In Manual of standards for diagnostic tests and vaccines. OIE, Paris, France.
Quinlivan, M., Cullinane, A., Nelly, M., Van Maanen, K., Heldens, J. and Arkins, S. (2004) Comparison of sensitivities of virus isolation, antigen detection, and nucleic acid amplification for detection of equine influenza virus. J. Clin. Microbiol. 42:759-763.
van Maanen, C. and Cullinane, A. (2002) Equine influenza virus infections: an update. Vet. Q. 24:79-94.
Webster, R. G. (1993) Are equine 1 influenza viruses still present in horses? Equine Vet. J. 25:537-538.

Specimen requirements: Preferred sample: nasopharyngeal swab, shipped overnight at room temperature.

Less preferred sample: 0.5 ml whole blood in EDTA (purple top) or ACD (yellow top) tube, shipped overnight at room temperature.

For specimen types other than those listed here, please call to confirm specimen acceptability and shipping instructions. For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround times:
A0001: 1 business day
S0077: 2 business days

Methodologies:
A0001: Rapid immunoassay
S0077: Qualitative reverse transcription real time PCR

Normal range: Nondetected