Conclusion Caturday: Sick Swinehaus Swine (Case 5)

Photo of TA Douglas (Left) and Professor Pocky (Right) taken by Dr. Haus

 

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Click for Test Case Tuesday:  Sick Swinehaus Swine

 

Click for Thoughtful Thursday:  Sick Swinehaus Swine 

 

Quick Review

Diagnosis:

🐽African Swine Fever🐽

 

Pathophysiological Point:

African Swine Fever (ASF) is an extremely fatal viral disease of domestic swine.  The ASF virus mostly infects the macrophages/monocytes of the pigs.  This causes a huge depletion in the immune cells of the animals.  The presentation of ASF is similar to Ebola in humans where the pigs have high fevers and start bleeding from different orifices.

 

 Questions, Answers, and Further Information:

 

Level 1 Questions, Answers, and Further Information:

1. Explain why the veterinarian contacted the state veterinarian to report the disease outbreak.  (HINT:  Think about the severity of the pigs sickness and the information given at the start of this post).  
   
   The veterinarian contacted the state veterinarian to report a suspected foreign animal disease case.  When a large amount of animals die showing concerning signs the state veterinarian needs to be notified to ensure samples are taken to quickly diagnose the disease.  If the disease is a threat to other animals and the country we need to diagnose it quickly to contain the outbreak.
   
   
2. Explain why the pigs are dying so quickly.  (HINT:  Think about the physical exam findings and the major finding that was found in the dead pigs' autopsies/necropsies)
   
   The pigs are dying quickly because they are bleeding from their noses, mouths, and other orifices.  When too much blood is lost, there is not enough oxygen getting to the cells of the body and the pig cannot survive without oxygen from the blood.
   
   
3. Challenge question, what do you think should be done on the farm now that African Swine Fever has been diagnosed?  (HINT:  This disease is 100% fatal in American domestic pigs, there is no vaccination, the disease has never been on American soil, and there is no way to treat this disease.  The full answer to this question will be multiple different approaches)
   
   There are multiple answers to this question that are noted below:
   
   1. The pigs on the farm will need to be humanely euthanized as they have all been exposed to the disease
   2. The farm will need to be put on a strict quarantine where nothing can come in or out from the farm (this will help stop disease spread)
   3. The farm will be decontaminated by folks trained in disease outbreaks to remove the virus from the farm
   4. Surrounding farms will be put on quarantine and be tested for ASF
   5. There will be an investigation into the source of the infection
      
   
   

   Helpful Links:

   • USDA information on African Swine Fever:                                     https://www.aphis.usda.gov/aphis/resources/pests-diseases/asf/asf
     
     
   • World Organisation for Animal Health information on African Swine Fever:  https://www.woah.org/en/disease/african-swine-fever/
     
     
   • USDA Biosecurity Principles:                                                           https://www.aphis.usda.gov/animal_health/emergency_management/downloads/ed_materials/bio_principles_handout.pdf
     

 

Level 2 Questions, Answers, and Further Information:

1. Affected pigs are showing the signs of redness throughout their skin.  The severe redness noted in these pigs tells us that they are undergoing what process at an increased rate?  (HINT:  The other signs of this process are heat, swelling, pain, and loss of function)
   
   The process that is occurring at an increased rate in the pigs is inflammation/the inflammatory process.
   
   
2. Pathophysiologically explain the steps of the above disease process that leads to redness in these pigs.  Be sure to mention all molecules, substances, and changes that occur in each step.
   
   During the acute inflammation process, histamine is released and leads to a vasodilation of the blood vessels around the injury site while also increasing the leakiness of the vessels around the injury site.  The increased vasodilation brings more blood to the area of injury (increasing healing factors) and the increased leakiness allows more fluid, immune cells, etc. to enter the injury site to assist with healing.
   
   
3. Challenge question, explain how African Swine Fever is similar to the Ebola virus in humans.  Be sure to note the pathophysiology, source of infection, physical exam findings, etc. that are similar between the two diseases.  (HINT:  For this one take the time to find reputable sources to learn more about each disease)
   
   There are many answers to this question.  Both diseases are from viruses that are able to spread easily between different hosts.  Clinical signs can be similar between the diseases (hemorrhagic fevers, gastrointestinal signs, rapid death, etc.).  Ebola virus also infections the monocytes/macrophages of the host.  And many more!
   
   

   Helpful Links:
   

   • Merck Vet African Swine Fever:                                             https://www.merckvetmanual.com/generalized-conditions/african-swine-fever/african-swine-fever
     
     
   • Level 2 and 3 FAO ASF Manual:                                                                  https://www.fao.org/documents/card/en/c/cc6300en
     
     
   • Level 2 or 3 CDC Ebola:                                                                              https://www.cdc.gov/vhf/ebola/clinicians/evd/clinicians.html
     
     

Level 3 Questions, Answers, and Further Information:

1. Describe your recommended plan and why you are recommending each part of your plan.  Please answer this question as if you are explaining it to a the farmer or the general public without a scientific background.  (Remember, this will be a sensitive conversation for most folks)
   
   In this situation, depopulation of the pigs on the farm will be required.  This is a sensitive topic as the farmers will likely have an emotional attachment to their animals, farm, and business.  In this case, it is important to speak empathetically with the farmers and addressing their feelings on having their livelihood and animals euthanized.  Discussing how fatal the disease is (essentially 100% in US domestic pigs) and the need to quarantine the farm to prevent the spread of disease to other farms will be important.  In this case, I would focus on the severity of the disease, the uncomfortable death these pigs and other infected pigs would go through, and focus on the most humane option of not allowing them to suffer.
   
   The farm will also be placed into a strict quarantine with no trucks, animals, people, etc. moving in and out.  The farm will be the central quarantine zone (also called the hot zone) as the outbreak is contained, studied, and hopefully eliminated.
   
   
2. Please describe the different potential sources of ASF on this farm.
   
   The different potential sources of the ASF in this farm could be visitors of the farm accidentally (or intentionally) bringing ASF to the farm, the family may have visited another farm/country and brought the disease back with them, there is a possibility that the outbreak started at another farm and spread to this farm via wild boar or a fomite, etc.
   
   
3. Please describe the different ways ASF can be prevented from entering into farms, regions, countries, etc.
   
   Biosecurity is the biggest prevention plan to keep ASF out of a farm, region, country, etc.  Biosecurity includes, but is not limited to, preventing animals/animal products from infected areas to enter into unaffected areas, not allowing humans who have traveled to an infected area to come to the unaffected areas without proper decontamination, showering in/out of facilities, boot washes, washing clothes, never feeding garbage or pig products to pigs, keeping equipment clean, quarantining new animals, etc.
   
   

   Helpful Links:

   • ASF Review Paper:                                                                        https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9409812/
     
     
   • Ebola Review Paper:                                                                      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691429/
     
     
   • USDA Outbreak Response Tools:                                                           https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/emergency-management/ct_fadprep_outbreak_response_tools
     
   
   

Day 3 Conclusion

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