Avian influenza and the South African poultry industry
Celia Abolnik
Poultry Section, Department of Production Animal Diseases, UP Faculty of Veterinary Science, Old
Soutpan Road, Onderstepoort, 0110.
The South African poultry industry continues to dominate the local agricultural sector contributing
some 22% of agriculture income in 2012 with a combined gross income set at over R 37.807 billion.
The total amount of poultry and eggs consumed in 2012 was 2.441-million tonnes, 31.5% more than
the combined beef, pork, mutton and goat consumed during the same period. In global terms, South
Africa is ranked 10th out of 204 countries listed for broiler production with a market share of 1.7%.
Of 204 countries listed for egg production, South Africa is ranked 26th with a market share of 0.7%.
In contrast to gallinaceous poultry production, South Africa is the world leader in ostrich production
with 75% of global market share. Meat, leather and feather exports earn about R1.2 billion annually.
The two production systems (ostrich vs. chicken) are as vastly different as the species themselves,
the major difference, in simple terms being that intensively-reared ostriches are farmed outdoors
and intensively-reared chickens are housed indoors. Outdoor farming of any poultry produces a new
risk: exposure to avian influenza viruses.
Avian influenza virus (AIV) is a ubiquitous symbiont of wild waterfowl where infection is sub-clinical
but large amounts of virus are shed via faeces and oro-nasal excretions into the environment. Where
poultry and wild ducks come into contact (usually through water) transmission of AIV may occur.
Two of the numerous AIV serotypes in their natural low pathogenic form (LPAI), viz. H5 and H7 are
prone to mutation in poultry and produce highly pathogenic avian influenza (HPAI), a lethal disease
that spreads quickly and has zoonotic potential. Other serotypes cause milder disease with lower
mortality rates in poultry but still affect production with significant economic impacts. Avian
influenza outbreaks in the ostrich industry have been both socio-economically and economically
devastating and the ostrich industry and national government remain at an impasse on various
control issues. Vaccination is not permitted and the recommended method of control remains by
stamping-out (culling), but recent a solution in the form of heat treatment of meat seems to offer
some hope for exporters. The stringent regulations imposed on the ostrich industry contrast the
situation in chickens. H6N2 strains have been endemic in the national flock since 2002 and although
controlled vaccination against H6N2 is permitted, this has not halted the outbreak. In fact, dramatic
genetic drift has occurred over the past decade, but the vaccine strain has not been revised.
Compounding the problem is the existence of a large and unregulated spent hen industry, facilitating
the spread and maintenance of many poultry diseases throughout South Africa. H6N2 is not a
zoonotic pathogen, but it does form a convenient, established “backbone” should H5 or H7 re-assort
into the chicken population. Continuous, rigorous biosecurity practice remains the best strategy for
controlling influenza A virus infections in poultry.