November 2021

TEXT-ONLY VERSION (scroll to bottom to download Newsletter in PDF)

Management Of Animal Disease Outbreak

Animal diseases pose a continuing threat to human and animal health, food security, the environment, and the national economy. Arguably one of the more significant challenges faced by veterinary services in the management of animal disease outbreaks is the protection of the environment during disease procedures. In the event of an outbreak, it is vital to properly manage and dispose of the infected animals to prevent any further spread of the disease. Currently the most common disposal methods include: burial, landfilling, incineration and composting (Chowdhury, et al., 2019).

Proper carcass management is often the most expensive aspect when it comes to outbreak response. Because outbreaks require immediate action, there is often a lack of sufficient time, funding, or alternative methods that lead to short-term measures being taken that may have longer-term consequences – especially for the environment (Miller, et al., 2020).  

In the past few months the Western Cape has seen multiple outbreaks of African Swine Fever (ASF) and more recently Highly Pathogenic Avian Influenza (HPAI). Proper disposal of animal mortalities can help prevent or mitigate the spread of pathogens. For some of the methods mentioned above, there is a limit to their use. This is due to concerns over biosecurity, transportation logistics, public perception and environmental impact (Costa & Akdeniz, 2019).  For example, transportation of infectious animal mortalities to incineration or disposal facilities introduces biosecurity risks and may further influence the spread of the disease. Burying animal mortalities is also limited by the availability of suitable sites and sites that are large enough to accommodate mass causalities. It is also further limited in the choice of site due to the risk of contamination of the groundwater and pathogen survival. Further concerns include the slow decay and odour of carcasses (Koziel, et al., 2018). Unfortunately, the burial of small quantities of infectious bird carcasses was recommended as a short-term, immediate response to the recent HPAI outbreak in the Western Cape.

Koziel, et al., (2018) also noted that while the disease type and number of cases of epidemiologically significant outbreaks between 2005 and 2016 varied from year to year, there is an overall trend of total cases increasing. This indicates the management of animal disease outbreaks and the disposal of infectious animal carcasses is a global concern and that there is an increased need for preparedness and effective emergency disposal methods.

One method that has been recognised as a bio-secure disposal method is composting.  Composting has previously been used in large-scale disease outbreaks across the world and has successfully demonstrated its efficacy as a disposal method in the deactivation both bacterial and viral pathogens. Research has shown that it eliminates pathogenic organisms such as Escherichia coli O157: H7, Salmonella spp., highly pathogenic avian influenza, foot-and-mouth disease and Newcastle disease (Costa & Akdeniz, 2019). EarthPet has consequently developed a closed composting system that has been used successfully in the ASF outbreak earlier this year. Solutions such as these provided by EarthPet exist as alternatives to the burial, landfilling and incineration of carcasses which has lasting and damaging effects on the environment.

It is vital that in emergency situations the long term consequences of the different disposal methods are thoroughly investigated and that effective strategies and procedures are put into place beforehand to respond to animal disease outbreaks efficiently & safely.

References

Chowdhury, S., Kim, G.-H., Bolan, N. & Longhurst, P., 2019. A critical review on risk evaluation and hazardous management in carcass burial. Process Safety and Environmental Protection, Volume 123, pp. 272-288. https://doi.org/10.1016/j.psep.2019.01.019

Miller, L., Miknis, R. & Flory, G., 2020. Carcass Management Guidelines – Effective disposal of animal carcasses and contaminated materials on small to medium-sized farms.. FAO Animal Production and Health Guidelines, Issue 23. https://doi.org/10.4060/cb2464en

Koziel, J. A. et al., 2018. Lab-scale evaluation of aerated burial concept for treatment and emergency disposal of infectious animal carcasses. Waste Management, Volume 76, pp. 715-726. https://doi.org/10.1016/j.wasman.2018.03.009

Costa, T. & Akdeniz, N., 2019. A review of the animal disease outbreaks and biosecure animal mortality composting systems. Waste Management, Volume 90, pp. 121-131. https://doi.org/10.1016/j.wasman.2019.04.047

EarthPet’s November Infographic:

Animal diseases pose a threat to the surrounding environment, animal welfare, public health, food security and the economy. Proper carcass disposal management is therefore vital to limit further spread of these diseases.

• There are over 200 known types of zoonoses.
• Over the last decade – Direct costs of zoonotic diseases has been estimated at over $20 billion and indirect losses at over $200 billion to affected economies.
• 40+ countries : Over 40 countries have been reporting various subtypes of High Pathogenicity Avian Influenza over the last 6 months.

Animal disease outbreaks can affect:

• Food & nutrition security.
• Livestock production and trade.
• Public health & safety
• Animal welfare
• Economy

• Currently the most common disposal methods for animal carcasses include: burial, landfilling, incineration & composting.
• Think long-term: Because outbreaks require immediate action, there is often a lack of sufficient time, funding, or alternative methods that lead to short-term measures being taken that may have longer-term consequences – especially for the environment.

Composting:

• Recognised as a bio-secure disposal method.
• Has previously been used successfully in large-scale disease outbreaks across the world.
• Effectively neutralises pathogens such as Escherichia coli O157:H7, Salmonella spp., Highly Pathogenic Avian Influenza, foot-and-mouth disease & Newcastle disease.

• Increasing Trend: There is an overall increasing trend in the number of epidemiologically significant outbreaks. Proper carcass disposal is therefore vital.