Summary
An
H5N2 avian influenza virus was isolated from ostriches in the Eastern
Cape Province of South Africa in July 2004. During a subsequent
national survey to determine the possible presence of the disease
in other areas of South Africa, specific antibodies against H5 avian
influenza were detected by the haemagglutination inhibition test
in ostrich sera collected in the Western Cape Province. However,
the sampling strategy used in the initial survey was developed to
accommodate practical constraints but did not truly reflect the
prevalence of the sero-reactor entities. A follow-up survey was
therefore conducted from March to May 2005 to obtain more representative
samples. None of the 15 126 serum samples collected from ostriches
aged 0‑4 months was positive, while 2.4% of the 14 664
serum samples collected from slaughter ostriches aged 5‑14 months
and 3.66% of the 8 791 samples collected from breeder ostriches
aged over 14 months were positive. Fourteen farms were inspected
in particular to identify relevant risk factors and risk mitigation
procedures that could minimise the spread of the disease. It was
concluded that biosecurity measures should be improved on ostrich
farms, in particular to minimise possible contact between ostriches
and wild birds.
Keywords
Avian influenza,
Epidemiology, Ostriches, Sero-surveillance, South Africa, Viruses.
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