Let’s consider some common misconceptions about biosecurity and how standardized outbreak investigations can help improve biosecurity outcomes.
Myth #1: Biosecurity is Making Progress
When asked whether biosecurity improvements are making progress, pig farmers or veterinarians often respond affirmatively. They cite increased implementation of biosecurity measures, such as washing trucks and thorough disinfection upon entering and leaving farms. But is this the best way to gauge progress? It might be better to evaluate the results that these biosecurity measures are intended to achieve. In the U.S., the incidence of PRRS and PED virus outbreaks in breeding farms remains high, and the introduction of PRRS virus, coronavirus, and other pathogens into growing pig herds continues at a high frequency. In some countries, including the U.S. and Spain, the mortality rate from weaning to market weight is high and increasing, indicating no overall improvement in pig health. Ultimately, the global spread of African Swine Fever (ASF) shows that no biosecurity progress is being made.
Why have results not improved despite more biosecurity measures being implemented? The pork industry has rapidly expanded over the past 30 years, leading to a significant increase in biosecurity risks. Geographically separated farming means that growing pigs are moved two or more times from birth to market weight, sometimes across long distances, which facilitates the rapid spread of local diseases. Dependence on hired labor and the development of specialized breeding farms, feed mills, and service companies, such as waste management and maintenance, has significantly increased the frequency of entries into farms by potential disease vectors, such as people, semen, feed, maintenance staff, vehicles, and equipment. As company sizes increase, specialized departments are formed, making coordinated decision-making increasingly difficult. Decisions affecting animal health are increasingly made by decision-makers who receive relatively little information from veterinarians. While there has been progress in implementing biosecurity measures, the lack of improvement in outcomes shows that the rapid development of the pork industry over the past 30 years has increased biosecurity risks faster.
Myth #2: We Know What Needs to Be Done
This is a refrain I often hear, especially from veterinarians in pig farming. The implication is that we already know what constitutes good biosecurity measures; there are plenty of published lists of good biosecurity practices, and if we implement them correctly, progress will be made. I completely disagree. For biosecurity measures to be effective, they must address significant biosecurity risks that increase the likelihood of pathogen introduction into the herd.
For a pathogen to be introduced into a herd, three failures must occur (Figure 1: The Concept of Three Failures to Identify Biosecurity Risks, Holtkamp et al., 2023). Biosecurity risk is defined as a circumstance, action, or inaction that increases the likelihood of one or more of the following three failures, and biosecurity risk analysis involves examining operational procedures to identify risks. Biosecurity risks arise from the implementation of operational procedures, including mandatory procedures in pig farming and procedures strictly followed to minimize biosecurity risks, such as thorough disinfection when entering and leaving the farm. Identifying biosecurity risks requires delving into the farming processes: Who performs the operational procedures? What is done regarding the layout, housing, and equipment? When will these procedures be carried out? Where will they be carried out? How are the procedures performed? Saying “we know what needs to be done” means that we have identified the most significant biosecurity risks. Based on my experience investigating outbreaks over the past decade, pig farmers and veterinarians rarely have a comprehensive understanding of the details of the production process to fully assess biosecurity risks. If veterinarians and farmers invest time in identifying and prioritizing biosecurity risks, they will find that real-life pig farming is more complex than imagined and it would be a mistake to assume that we already know what needs to be done.
Myth #3: Outbreak Investigations Are Only Valuable if They Identify the Cause of the Outbreak
Outbreak investigations are a great opportunity to identify and prioritize biosecurity risks. You may have heard the phrase “Never waste a good crisis.” An outbreak is a crisis, and it is an opportunity to learn, but learning is not guaranteed. If outbreak investigations are conducted well to identify and prioritize biosecurity risks, the information obtained will always be beneficial when invested in the investigation.
In 2021, the Swine Health Information Center (SHIC) funded the development of a Standardized Outbreak Investigation Program. A working group of 14 pig veterinarians was established to develop terminology, methods, and tools. The standardized outbreak investigation method is conducted as a comprehensive biosecurity risk analysis and epidemiological investigation. Risk analysis for biosecurity in pig farms involves collecting and evaluating information about biosecurity risks related to pathogen introduction into susceptible herds.
The methods and terminology developed for standardized outbreak investigations borrow heavily from the risk analysis and Hazard Analysis Critical Control Points (HACCP) methods used in the food industry. HACCP originated from NASA in the 1960s. It was designed as a systematic quality assurance method to identify food safety risks and ensure that food provided to astronauts was free from contamination. NASA worked with food processing engineers to develop a method to ensure safe food products by analyzing and monitoring the production process rather than the end product. The emphasis on analyzing and monitoring food safety risks during production is what makes HACCP applicable to analyzing biosecurity risks in pig farming.
The standardized method for outbreak investigation in actual infections aims to identify and prioritize biosecurity risks and implement biosecurity control measures to address these risks which will be discussed in a subsequent article.
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