homepage logo

Biosecurity is key to battling a potential ASF outbreak

By Staff | Aug 6, 2019

If African swine fever (ASF) would reach the United States, experts agree the outcome could be potentially detrimental to Iowa’s agriculture industry. Practicing daily biosecurity measures could help not only keep ASF from affecting your herd, but is suggested in battling other foreign animal diseases.



African swine fever (ASF) has been in the headlines for close to a year and attempts are being made to keep it from spreading into the United States.

“African swine fever is a foreign animal disease that imposes an increased risk to Iowa due to our important role in the swine industry,” said Dr. Andrew Hennenfent, emergency management coordinator for animal health at the Iowa Department of Agriculture and Land Stewardship during a webinar discussing topics of ASF held last month.

Background of ASF

Hennenfent said ASF was first documented in Africa in 1921. It spread to Europe and eventually left the African continent in the late 1950s.

The virus continued to spread to parts of Spain and had since been eradicated in those areas before the most recent outbreak.

Hennenfent added it was the mid-2000s that ASF was detected in Georgia – a country located at the boundary of Europe and Asia and it continued to spread during that time, reaching into Russia.

Detection of the virus continued with findings in Ukraine in 2012 and Lithuania and Poland in 2013.

The Peoples Republic of China detected its first case of ASF in 2018 and detections continue today with the virus reaching hogs in Western Europe, up into Belgium.

“Those first detections in China were just under a year ago,” he said. “They have since been reported in all provinces of China, so it is pretty widespread throughout the country. It is in every aspect of their production system and it’s also started spreading to other countries in Asia. African swine fever is now present in at least 18 countries worldwide and some predictions say African swine fever could remain in circulation on the Asian continent for at least a couple of decades.”

The spreading of ASF

Hennenfent said ASF is a very large virus and it is important because that factors into why it is so difficult to develop a vaccine and why it is able to survive in the environment.

“What kept it in circulation so long in Africa is because the natural hosts of the virus are warthogs and soft ticks,” he said. “They get sick from the disease and carry the virus.”

The warthogs and soft ticks are constantly infecting each other.

“The warthogs carry on with their normal life cycle, they burrow underground. The ticks live there. So, when the ticks or warthogs come into contact with domestic pigs, the virus makes the domestic pig very sick,” he said.

Fortunately, in Iowa, there isn’t the species of tick that can carry ASF and there isn’t a wild or feral hog population to contend with.

The virus, Hennenfent, said is very robust.

“It survives easily outside of the pig,” he said. “It gets into all of their body fluids. It is very hardy in the environment. It can survive in salt-cured hams for many months and unprocessed meats – they need to be heated to as much as 158 degrees for 30 minutes. It can survive several years in frozen carcasses. That’s what makes this disease so challenging compared to other viruses. This virus is in organic material – blood, feces, urine. It can survive a very long time- even at room temperature.”

Pigs become infected with ASF by coming in direct or oral contact with something carrying the virus.

“Anything that can pick up that virus can carry it from one pig to another,” he said. “You, equipment – anything that will act as a passageway for that virus that it can hitch a ride to another pig and be the way the virus spreads.”

However, it cannot float in the air.

In China, Hennenfent, said where they are dealing with the largest outbreak of ASF the world has ever seen, they have done some studies on what has been the most common pathways of the virus to spread from one farm to another.

The transportation of live pigs and pig products is the least common method, researchers have found. The No. 1 way they have determined the virus is being spread around China is by being carried onto farms on workers or their vehicles that have not been disinfected properly.

“It could be someone walking through a pig pen that is not adequately cleaning their shoes. They stepped in feces or urine from a pig that has African swine fever and walk around pigs that are not sick from it,” he said. “A little amount of contaminated urine or feces is enough to get pigs in another pen sick. It is virus to snout. Anything that will physically pick up that virus and carry it to another pig is going to be what can expose them to the virus, ultimately making them sick.”


“Good biosecurity practices could potentially prevent half of the spread of African swine fever in China that is currently happening,” said Hennenfent, “There is no vaccine. And there is no specific treatment. The No. 1 prevention for it is biosecurity.”

Hennenfent recommends not only using proper biosecurity during an outbreak, but on a daily basis.

Daily biosecurity includes wearing site specific clothing – footwear and coveralls for each farm and leaving those clothes at the farm if possible. Even better is a facility that features a shower where workers can shower in and shower out.

“Essentially treat each animal facility as if it is its own island,” he said. “Regulate and monitor everything that is touching those animals, touching the inside that could potentially be carrying in a disease agent that could be making your animals sick.”

With African swine fever and other foreign animal diseases, ask anyone coming into contact with your farm about international travel.

“Since this can be carried on clothing and meat, we recommend a five-day down time when someone returns from a country that has African swine fever before they step foot on a facility in the United States that has pigs,” he said. “Controlling and tracking traffic on and off your farm – we want people to keep in mind that anything physically crossing onto their farm – there is always a possibility it could be carrying a virus or bacteria that can make their animals sick.”

Hennenfent also advises against bringing back any meat products from countries that have animals carrying the virus.

“This is for people, anyone even outside of agriculture – don’t bring meat products back to the United States,” he said.

Scaling up on biosecurity after coming back from a fair or show is also very important.

“We are in the height of summer right now,” he said. “We have animals moving to and from shows. We need to be isolating those from the rest of their farm for a period of time; working with their veterinarian to be sure they are not sick and didn’t accidentally bring something back and et the rest of their animals sick.”

Hennenfent said it is also important to teach others about biosecurity.

“What we want to keep in mind is that biosecurity on anyone’s farm or facility is only as strong as the weakest link or the person that knows the least about biosecurity,” he said. “We want people to serve as biosecurity ambassadors and educate their friends and family outside of agriculture the importance of keeping African swine fever outside of the United States.”

“Good biosecurity not only starts on the farm, but continues when the folks go off the farm and it is everyone’s role and responsibility to participate in good biosecurity,” he added.

What else can you do to protect your pigs?

Hennenfent said updating their premise identification and contact information are the steps that farmers and producers can take today.

Premise identification is used to track the movement of animals.

“In the event of an outbreak, having those premise identification numbers in our system and linked to the correct contact information allows us to rapidly notify people if they are in an area impacted by the disease and also allows us to trace forward and trace back investigations and figure out where that disease has touched and hasn’t touched as quickly as we can,” he said.

Hennenfent also recommends having a strong relationship with your veterinarian and to contact those proper authorities if you feel there is something wrong within your herd.

“You know your animals best,” he said. “Your veterinarian knows your animals best. If there’s anything you think is out of the ordinary it is always better to err on the side of caution and let your federal health officials know so they can take a look at it and decide if there should be further testing.”

Response at the state level for a foreign animal disease

Hennenfent said their initial response efforts for ASF or any foreign animal disease consists of three phases.

  • Detection of the disease.

This takes the form of a producer and veterinarian reporting any concern that there may be a foreign animal disease outbreak.

“This reporting immediately prompts a conversation between our state veterinarian and the USDA area veterinarian in charge,” he said. “They talk about the case and if what is being reported is suspicious, they will dispatch a foreign animal disease diagnostician. That is a federal or state veterinarian that has been through special USDA training to diagnose and screen for foreign animal diseases”

  • Contain it.

Hennenfent, said after confirmation of the disease, they will work to contain it and this will lead to quarantining the facilities and establishing a control area.

“The USDA will issue a national recommendation and in the case of African swine fever, that no live pigs be on U.S. roadways for a certain period of time while USDA and the different states figure out which areas of the country have been exposed,” he said.

During this period of time, main investigations will be conducted and any site with positive pigs or site with confirmed exposure of African swine fever will be quarantined and nothing will move on or off of that site.

A control area is established, basically creating a region around the infected site where if there are any other sites within that region that also have hogs, if we are dealing with African swine fever, would not be allowed to move anything on or off of their farm.

“The reason that is done is we want to ensure only movements that are happening are as low risk as possible,” he said.

  • Eliminate it.

This next step, Hennenfent, said would start happening while in the biocontainment phase.

“This would be where we want to, any pigs that are sick with African swine fever, we would want to pull out all of the stops of an outbreak and stamp it out as soon as possible,” he said. “Our goal would be any infected or sick pigs to be depopulated on those farms within 24 hours.”

The goal is to dispose of those carcasses after the animals are depopulated on that site.

“One thing we like to highlight is with any production animal system, or any size farms, something that folks can do right now is reach out to their regional DNR office. They can help you construct some maps of your premise with water tables, things along those lines to let you know what methods of disposals are and are not possible on your property so you can give that some forward thought,” he said.

Key things to know about ASF

Hennenfent said it is important to note there is no impact on human health.

“We cannot get sick from it, even if you were to eat a pork chop from a pig that died from African swine fever. The virus cannot infect you. The virus cannot live in our body. The most we can do is carrying the virus on our skin, on our clothes,” he said.

It won’t make people sick, so why do we care?

“There would be severe economic impact on the U.S. and especially Iowa if we were to get African swine fever,” he said. “That would not only affect the swine sector of our agriculture here in Iowa, but also affect some of our plant-based friends as well.”

Pigs raised in Iowa, Hennenfent, said consume about a quarter of all corn acres and a quarter of all bean acres in the state.

“If you think about that, if we are losing a large amount of pigs in Iowa, there are not going to be as many pigs to consume the corn and soybeans we raise, so this will also impact the corn and soybean market,” he said.

Hennenfent said it is best we keep African swine fever out of the U.S. instead of trying to eradicate it once it is here.

“But if it does come to the United States it’s in everyone’s best interests to eradicate it as quickly as possible,” he said. “If we fail at eradicating it as quickly as possible and it comes wide spread, it could not only result in years of trade restrictions, but also a decrease in domestic production from an increased mortality rate and in the long run, that could drastically increase the cost of doing business from what it is now.”

Please Enter Your Facebook App ID. Required for FB Comments. Click here for FB Comments Settings page