SARS, Hendra virus, avian influenza – emerging infectious diseases that can be devastating. And in 70% of cases, the source of outbreaks of diseases like these is an animal. So, is culling wildlife the best way of protecting humanity from deadly viruses?
Dr Chris Degeling from the University of Sydney will be speaking at the Australian Veterinary Association Annual Conference tomorrow about disease control and wildlife which are the major reservoir for zoonotic diseases (that can pass between animals and people). Wildlife is the primary source of emerging infectious disease threats to human populations.
“When a disease outbreak occurs, such as the rabies outbreak in Bali last year or avian influenza in Asia, the aim of culling is to eradicate a host species. And most agree that depopulation will be most effective when infection rates are high in the animals and where large numbers can be found in close proximity to each other.
“However, infection control strategies for animal-borne diseases that hinge on depopulation are becoming increasingly controversial. Both experts and the public have legitimate conservation and animal welfare concerns,” Dr Degeling said.
Culling domestic animals and wildlife populations is also contrary to the One Health concept which continues to gain momentum within the scientific community and the general public.
“The One Health concept focuses on the common good which is concerned with what’s in the best interests of humans, animals and the environment,” he said.
According to this concept, human, animal and ecological health are explicitly linked. And yet despite this, culling domestic animals and wildlife populations remains a key component of institutional responses at times of heighted zoonotic risk. This, Dr Degeling says, is not the best course of action when it comes to long-term disease control.
“Widespread culling of animals, like we saw in Hong Kong with the culling of poultry in response to H5N1 highly pathogenic avian influenza, can be an impossible challenge with unpredictable health and environmental consequences. In the case of H5N1, 250 million poultry were destroyed resulting in a $10 billion loss. Culling poultry was a decisive measure and eradicated avian influenza in discrete and contained populations, but it has not been effective in eliminating the disease completely as outbreaks still occur in some poultry production systems in South East Asia.”
Dr Degeling argues that evidence as to the overall health benefits and cost-effectiveness of culling as a sustainable solution to many zoonotic risks also remains inconclusive.
“If we are going to effectively control animal-borne infectious disease, we need to establish methods and processes for sustainable collective action that promotes the health and wellbeing of humans, animals and the environment. For this to happen, we need to consider all the options in terms of a response including public education, biosecurity processes and legislation as well as vaccines,” he said.
The AVA Annual Conference is being held 22-27 May at the Adelaide Convention Centre.