Fast Facts: What You Need To Know About The African Swine Fever

We Filipinos are known to have a centuries-long love affair with pork, devouring all parts of the pig from the insides to the skin. This runaway consumption has made the country pork power in the global market.

It has been pointed out in the Senate that the Philippines produced almost 2.3 million metric tons of pork, with the country’s national herd totaling to 12 million, including a 1.75 million sow population this 2019.

About a month ago, an outbreak on the so-called African swine fever (ASF) has surfaced Philippine news agencies confirming the arrival of the virus in the country.

The virus now threatens one of the country’s biggest industries, eighth when it comes to volume, representing a total worth of P260 billion.

Be alert and stay informed. Here are some of the basic questions and answers about the ASF virus.

What is African swine fever?

According to the National Meat Inspection Service (NMIS), African swine fever (ASF) is a highly contagious condition of pigs, including bush pigs, warthogs, wild boars, and wild pigs.

The virus causes pigs to lose their appetite, as well as experience episodes of high fever. It also causes hemorrhages in the skin and internal organs, causing high death rates.

What causes African swine fever?

African swine fever is a double-stranded DNA virus and the only member of the Asfarviridae family (ASF related virus), which exhibits the characteristics of the Poxvirus family (smallpox etc.) but is structurally distinct.

What are the clinical signs of the ASF virus?

The clinical signs of ASF can manifest in different forms.

Clinical signs include a fever (40.5-42 degrees Celsius), vomiting, diarrhea, reddening of the skin at extremities, chest and abdomen, anorexia, and abortion.

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How do I recognize the signs of ASF in pigs?

The clinical signs of ASF range from mild to severe depending on the strain of the virus.

With the severe form, almost all affected pigs die. Less severe forms may result in milder clinical signs. Some clinical signs of ASF are:

  • Abortion (which can occur in pregnant sows)
  • Appetite loss
  • Appearance of blue marks on the skin and extremities
  • Death (maybe sudden with few signs prior)
  • Diarrhea
  • Discharge from the eyes and nose
  • High fever
  • Lethargy
  • Vomiting
  • Weakness

How is ASF transmitted?

The transfer of ASF virus between animals can happen through various channels. It can occur either by direct contact of sick and healthy animals, and indirectly through contaminated feed, or on contaminated clothing, and vehicles.

Animals that have recovered from the infection can continue excreting virus throughout their lives. In addition, ASF can also be transmitted via soft-bodied ticks of the genus Ornithodoros. Once the pathogen has found its way into the environment, it can stay and remain infectious for a long time.

Non-infected animals also play a special role in the spread of the virus. Foods produced from infected animals that are consumed by non-infected animals, or even persons, can carry the virus and can remain infectious for several months. One example is processed foods.

Once affected foods find their way into previously ASF-free places, it can cause infection in all types of pork in the region. Food scraps should, therefore, be disposed of in such a way that they cannot reach other animals that are not infected by the virus.

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How dangerous would it be for those animals diagnosed with ASF?

The incubation period for ASF is between five to 15 days, with death occurring within six to 13 days post-onset of illness.

In domestic swine, the mortality rate is very high for swine suffering from the acute form of the disease, often approaching 100%. In the sub-acute, or chronic forms of the disease, mortality is usually much lower varying between 30%-70%.

How is ASF diagnosed?

Diagnosis can be either by identification of the virus by direct antigen detection by immuno-fluorescence, tissue culture inoculation, or detection by polymerase chain reaction (PCR).

Serological tests such as an indirect antibody fluorescent test, or ELISA can identify anti-ASFV antibodies in blood samples taken eight to 21 days post-infection.

How long does it take to test for the ASF virus?

A quick test could be carried out within a few hours after the samples are sent to the laboratory. If the initial result is positive, further confirmatory tests will be conducted as soon as possible and the laboratory report could be provided within 24 hours.

Are humans susceptible to the virus?

As the ASF virus cannot be transferred to humans, it is not dangerous. The consumption of foods originating from infected animals is not dangerous to health either. Direct contact of humans with infected animals does not pose a risk either.

However, humans can become carriers of the virus once they ingest the affected pork or if they get close to the infected meat. The virus can also survive even if the meat has been processed or canned. Well-cooked pork and pork products are safe for consumption.

Given that ASF will not be transmitted to a human, why is it necessary to take action to guard against the disease?

ASF is a highly contagious swine disease which could cause massive death in pigs within a very short period of time. As currently, there is no vaccine or treatment available, this disease poses a severe threat to the pig rearing sector.

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How is ASF treated?

There is no treatment or vaccine for ASF.

How can the outbreak be controlled?

Killing the herd of infected individuals is one way of preventing the spread of the disease.

Remains of infected animals should be disposed of either by burning or burial and the premises of the infection should be thoroughly disinfected. Setting up a control zone around any infected premises and monitoring the movement of pigs within the zone is also a must.

In African countries where the disease is enzootic (which means that the disease is consistently prevalent in the region), it is important that pigs are not brought into contact with ticks that can carry the virus.

What measures should the Government take to ensure the food safety of fresh pork?

The government should be closely monitoring the situation, staying vigilant and implementing corresponding measures in a timely manner.

  1. All imported and local pigs must undergo stringent antemortem and post-mortem inspections in slaughterhouses to ensure that pigs supplied to the market are fit for human consumption.
  2. All live pig consignments from the city should be accompanied by valid health certificates which ensure that live pigs are from reliable sources and are in good health
  3. All vehicles and personnel entering and leaving pig farms should be requested to perform accentuated cleansing and disinfection.
  4. Suspend importation of products from infected hog breeders.
  5. Devise a surveillance plan on ASF and conduct sampled testing when there are pigs suspected to be infected.
  6. Provide assistance and loans to facilitate farmers purchasing facilities to enhance biosecurity.
  7. Step-up cooperation with local governments of each barangay, infected or not, to crack down on illegal importation of infected meat.

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What actions has the government done in lieu of the ASF Outbreak ?

  1. Before the news that ASF has triggered swine deaths was shared with the public, the Philippine government had already forwarded tissue samples of the affected hogs to various laboratories to determine what causes the death of the pigs.
  2. The government has also imposed the “1-7-10 Protocol” in areas affected by ASF
  3. Quarantine checkpoints were also set up in areas that are within a radius of one kilometer from farms suspected to be affected with ASF. All of the pigs found within that area are to be killed.
  4. According to the Department of Agrarian Reform (DAR) more than 7,400 pigs have been killed in the affected areas.
  5. Authorities also conducted surveillance which limits any arrival or transfer or animals, specifically pigs within the 7-kilometer radius.
  6. Farm owners in the 10-kilometer radius need to report any pigs showing symptoms of the disease.
  7. All pork imports from ASF-affected countries such as Cambodia, China, Mongolia, Vietnam, some areas in Laos, Myanmar, and South Korea are banned.
  8. The Department of Agriculture has allotted a budget of P82 million for further prevention methods to halt the spread of the disease.
  9. Part of the P82 million will also go to providing financial aid amounting to P3,000 each to affected hog raiser.

What can consumers do to ensure that the virus does not spread further?

To stop the spread of the virus to other herds, consumers must strictly comply with the rules and regulations on the importing of foods from risk areas.

The public should not buy pork from unknown sources and should thoroughly cook the meat before consumption. Always look for the NMIS seal as a guarantee. Uneaten foods containing animal ingredients should be disposed of in such a way that they cannot be reached by other animals.

Also, everyone is encouraged to report incidents of diseased animals to their respective municipal, city, or provincial veterinary offices.

Other sources: Rappler, Canadian Food Inspection Agency, Biosecurity New Zealand, Epizone, US Customs and Border Inspections