As the global dependence on pork production rises, many countries have turned toward swine systems in order to establish themselves as a strong international trade presence. Over the past one hundred years, however, the pork industry has faced tremendous implications due to outbreaks of African swine fever. From its first appearance in Kenya in the early 1900s, to the current epidemic in China, ASF has cost individual countries upwards of $1 billion USD in economic losses. This includes the trade deficit that comes as a result of not being able to export infected pork, as well as the need to employ expensive eradication measures in affected swine systems. Though these measures are vital to prevent the spread of ASF, many productions are unable to afford them. The highly contagious nature of African swine fever, combined with the inability to implement proper eradication and prevention measures in swine facilities worldwide, has resulted in immense financial deficits and restricted trade opportunities for many countries.
Domestic pigs were originally exposed to African swine fever through contact with infected feral pigs and warthogs. Once contracted by a domesticated pig, the disease rapidly infects many others within the herd due to its high transmission rate. Other forms of contagion include contact with contaminated materials such as farm equipment, infected pork products in feed, food waste, and infected fomites. The most common fomite is the soft tick of the Ornithodoros genus, which contracts the virus while feeding on an infected pig and passes it along to others. Throughout Europe and Asia, the high wild boar density and presence of soft ticks fosters an easily transmittable environment for ASF.
Once a pig contracts African swine fever, it may begin exhibiting outward signs such as high fever, depression, anorexia, and hemorrhages in the skin. In acute strains of the virus, the mortality rate is nearly 100%, and death most commonly occurs within six to thirteen days of showing symptoms. In chronic or subacute cases, symptoms include weight loss, intermittent fever, respiratory issues, chronic skin ulcers, and arthritis. These strains are less virulent, and have a much lower mortality rate that ranges from 30% to 70%. The symptoms of chronic cases, however, persist for longer periods of time. Although many pigs exhibit symptoms shortly after contracting the virus, certain breeds are less likely to show outward signs. African wild suids are common vectors of ASF as they do not express any of the common indicators, but are equally capable of transmitting the disease as those who do.
When a pig in a herd is suspected to have ASF, laboratory tests must be performed. This is done by isolating the virus from either a blood, lymph node, tonsil, or kidney sample, and identifying the viral agent. If confirmed, the farmer of the affected herd must restrict the movement of infected pigs and begin proper eradication procedures. Since there is no available vaccination, the most effective way to eradicate the disease is through slaughtering contaminated pigs. Afterwards, strict cleaning and biosecurity measures must be implemented to prevent future outbreaks.
In disease free countries, it is imperative to establish trade regulations that closely monitor pork importation. By ensuring that pork is not being imported from ASF affected areas, and waste products are being properly disposed of, countries that have not experienced outbreaks can protect their swine systems. Minimizing the movement of pigs within a facility is also crucial to preventing the spread of ASF. Keeping pigs centralized in one area for as long as possible, and thoroughly cleaning after a herd is moved, significantly decreases the probability of infection. In the U.S. alone, preventing the introduction of ASF into the pork supply has an estimated net benefit of $4,500 million dollars. This equates to around 5% of the total value of pork sales within the United States. By having strict biosecurity measures such as shower in/shower out policies, time requirements between contact in different swine barns, and trade bans on pork from certain countries, the U.S. has successfully prevented the rise of ASF in its pork supply.
Unfortunately, other countries have not been as successful in keeping the virus out of their nation. Over the past three months, China has reported its first major outbreak of African swine fever across twelve of its provinces. The first outbreak occurred in the northern province of Liaoning, and quickly spread to the southern provinces by the end of August. This is the first documented case in East Asia, which indicates the worsening contagion of ASF. Small farm producers dominate the Chinese pork industry, and often lack the financial means to implement strict biosecurity measures and purchase manufactured feed for their stock. Many of these systems opt for potentially contaminated kitchen waste rather than expensive, manufactured pig feed. Despite bans on feeding kitchen waste to pigs, the Ministry of Agriculture has stated that 62% of the country’s first outbreaks occurred as a result of this practice. These small farms often have more lenient biosecurity policies in place, which increases the threat of ASF outbreaks.
As the world’s top pork industry, China has produced over 54.65 million metric tons of pork in 2018, and is home to over half of the world’s pig population. This epidemic has resulted in the culling of hundred of thousands of pigs in an attempt to contain the virus. Infected provinces have since placed tremendous trade bans on live pigs, and the Ministry of Agriculture has banned inter-provincial trade between ten areas surrounding affected provinces. Due to the trade disturbances within the country, the price of pork products are expected to increase dramatically. The upcoming Lunar New Year also poses a threat to the price of pork due to its anticipated high consumer demand. In order to keep up with this demand, China must turn toward trade with other countries. However, recent U.S.-China trade war developments now allow pork products imported from the U.S. to be subject to tariffs. With limited local pork available, consumers will have to either pay high taxes on imports, or rely on other major pork producing countries such as Canada and Brazil.
Though substantial, the economic impact on producers and consumers is not the only consequence of an ASF outbreak. Once an infection is identified, there is an immediate threat to worldwide food security. Pork constitutes 36% of the world’s meat intake, and is the primary source of meat in countries where beef production is limited. Although ASF is not transmittable to humans and, therefore, poses no public health risk, there are many regulations in place that prevent the entrance of infected products from entering the food supply. Without these measures, ASF would spread far more rapidly than it already has. In addition, ASF hinders the amount of pork that can be produced globally. In 2018 thus far, over 118 million metric tons of pork have been produced. With the recent outbreaks in China, however, over 38,000 infected pigs have been sent to slaughter, and over 200,000 have been quarantined. This dramatic decrease in healthy pigs significantly inhibits the amount of pork products that can be produced.
Another concern with ASF outbreaks is the ecological impact. In certain countries, attempted preventative measures disrupt the natural ecological balance of wild animals. One of the main causes of African swine fever in domestic animals is contact with infected wild pigs and warthogs. Throughout the European Union, hunting practices have been used to eliminate these possible wild vectors of ASF. A recent study conducted by the European Food Safety Authority, however, concluded that substantial hunting of wild boar has no impact on the introduction and spread of African swine fever in domestic pigs. To better understand the impact of wild boar distribution in relation to ASF, the European Food Safety Authority is currently funding a project called ENETWILD. The project is primarily focused on gathering information on the geographical distribution of a variety of wildlife hosts, and using the aggregated data to analyze the effect on ASF transmission. Through continued research and active efforts, lessening the ecological impact of African swine fever can be made possible.
When an ASF outbreak occurs, countries across the entire globe are affected. The prominence of the pork industry in the international economy allows for tremendous consequences when disrupted. Massive economic losses, restricted trade opportunities, and local ecological disturbances threaten the infected areas, while harsh trade restrictions and fluctuating pork prices impact those that are not. Without a cure, African swine fever will continue to spread among pig populations and plague the world’s pork industry.
A variety of different sources were used to gather the information previously presented. The OiE: World Organisation for Animal Health is a French based, international organization that researches and reports on animal related diseases on a global level. The OiE website is a reliable source for information regarding the clinical signs, transmission, and diagnosis of African swine fever because of the expertise of those who write the articles. The authors are knowledgeable about the disease, and their articles are used to inform the global public. Similarly, the European Food Safety Authority is a government agency based in the European Union. Their website covers a wide range of topics regarding public health concerns throughout the EU, making it a reliable source for information on the effects of African swine fever. Another reliable citation is the Food and Agriculture Organization of the United Nations. The FAO website was used for statistics concerning the worldwide production of pork, as well as the production of individual countries. This website provided reliable information, as the U.N. is responsible for documenting accurate statistics and making them accessible to the public.
Despite the use of dependable websites, some less reliable sources were used as well. Wikipedia articles provide a comprehensive overview of African swine fever, however they can be edited by any member of the public. This could result in inaccurate information being published, and subsequently relayed to the reader. Thomson Reuters is a mass media firm based in Canada. Though the company reports on an international basis, the articles on their website could be slightly skewed since it is a news outlet. Inaccuracies, though probably less significant than in the Wikipedia article, could still be present.
Throughout the research process, it became apparent that the information gathered was sufficient when no new details were being uncovered. By covering a wide variety of topics regarding ASF, a comprehensive paper was able to be written, and no additional research needed to be done. Though the information provided may not be sufficient for an official scientific paper, it is satisfactory for research conducted by a member of the lay-public.