In this article, Dr. Shahn Bisschop, a poultry specialist veterinarian and senior lecturer in the Faculty of Veterinary Science's Department of Production Animal Studies (PAS) sheds more light on the current outbreak of avian flu caused by a Highly Pathogenic (HPAI) strain of H7N6 avian influenza. Dr Bisschop, who is also a Diplomate of the American College of Poultry Veterinarians (DACPV) and a consultant for the South African Poultry Association (SAPA) on disease control explains how the disease can possibly be controlled and why it is difficult for people to become infected with the current strains circulating in South Africa.

What is avian influenza or bird flu?

Avian influenza (AI) is a highly contagious viral disease that affects both domestic and wild birds. The current outbreak caused by a Highly Pathogenic (HPAI) strain of H7N6 avian influenza is causing the most concern at present. The strain was first confirmed in chickens near Delmas at the beginning of June 2023. This virus is a novel mutation of a strain of avian influenza which originated from wild birds at or near the location of the original outbreak.

Can humans get avian flu? 

It is extremely difficult for people to become infected with the strains of avian influenza presently known to be circulating in South Africa. Avian flu is very contagious and deadly to chickens and a few species of wild birds. To humans almost not at all – the virus is not adapted to colonizing human cells. We do know that viruses can mutate over time, and it is possible for avian influenza to develop into a disease of humans, as has happened a few times earlier in history. For this reason, it is crucial that outbreaks are controlled as quickly as possible.

How long does avian flu last?

The incubation period is 14 days - that is the period between infection and the first clinical signs. An outbreak is considered to have ended 2 incubation periods (28 days) after the last bird shows clinical signs. In individual birds the course of the disease may be very short - a few days between first clinical signs and death in many birds. In others they will take longer to die, in still others, they will recover after a period of sickness lasting a few days to possibly a few weeks.

How can it be controlled or avoided?

Biosecurity and vaccination are used to manage diseases. Biosecurity refers to a wide range of steps taken by poultry producers to limit disease spread between farms; in the case of the current H7N6 HPAI strain, these have not been as successful as we had hoped, implying that we urgently require access to vaccines that will protect birds from dying from the disease while also slowing the rate at which the disease spreads between flocks.

In the event of outbreaks, it is usually the role of the government to ensure that infected birds are culled in order to reduce the risk of spread of the disease from infected flocks. In order to encourage farmers to agree to the culling of at-risk birds, the government needs to compensate farmers for the associated costs.