Todayโs path rounds are on ๐ฆ๐ข๐ฅ๐ค ๐ฌ๐ฉ๐จ๐ญ ๐ฅ๐ข๐ฏ๐๐ซ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ข๐ฅ๐ค ๐ฌ๐ฉ๐จ๐ญ ๐ฅ๐ข๐ฏ๐๐ซ is a parasitic infection caused by the parasite ๐๐ฌ๐๐๐ซ๐ข๐ฌ ๐ฌ๐ฎ๐ฎ๐ฆ. Itโs called milk spot liver because the liver gains numerous white spots over its surface due to scarring.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This disease is seen in pigs!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ญ๐ก๐ ๐ฌ๐ฉ๐จ๐ญ๐ฌ?
The spots are caused by ๐ฅ๐๐ซ๐ฏ๐๐ฅ ๐ฆ๐ข๐ ๐ซ๐๐ญ๐ข๐จ๐ง of the parasites through the liver, which leaves large tracts where the larvae were present. These tracts heal by scarring, producing the white scarring that we see at necropsy.
๐๐ก๐๐ญ ๐ข๐ฌ ๐ญ๐ก๐ ๐ฅ๐ข๐๐ ๐๐ฒ๐๐ฅ๐ ๐จ๐ ๐ญ๐ก๐๐ฌ๐ ๐ฉ๐๐ซ๐๐ฌ๐ข๐ญ๐๐ฌ?
The adult parasites live in the gastrointestinal tract of the pig, so infected pigs will shed eggs in their feces. Other pigs will then eat the egg-contaminated feces, a contaminated dung beetle or a contaminated earthworm, introducing the eggs into their body. From there, the eggs will hatch and form larvae, which migrate through the liver to reach the bloodstream. Blood flow will move the larvae into the lungs, where they will burrow out into the airway and get coughed up by the pig. From there, they are swallowed and develop into adults in the gastrointestinal tract. Gross.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
These lesions are generally considered an ๐ข๐ง๐๐ข๐๐๐ง๐ญ๐๐ฅ ๐๐ข๐ง๐๐ข๐ง๐ (meaning it didnโt cause clinical signs or affect the animal). However, animals with this condition cannot be processed for human consumption, so there can be economic impacts for pork producers. Ascaris suum is ๐ณ๐จ๐จ๐ง๐จ๐ญ๐ข๐, meaning it can infect humans, so it is important to keep infected pork products out of the food chain! In some heavy infestations, pigs can also show increased respiratory effort (called ๐ญ๐ก๐ฎ๐ฆ๐ฉ๐ฌ) due to larval migration, weight loss and generally just donโt feel well.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Because the eggs are shed in the feces, a ๐๐๐๐๐ฅ ๐๐ ๐ ๐๐จ๐ฎ๐ง๐ญ can be done to assess the number of eggs present in a pigโs feces. However, most diagnoses come from seeing milk spots in the liver at necropsy.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
Treatment typically involves ๐๐ง๐ญ๐ก๐๐ฅ๐ฆ๐ข๐ง๐ญ๐ข๐๐ฌ (dewormers) to specifically target the parasites. In terms of prevention, the best method is keeping barns clean, and keeping pigs off soil surfaces so they canโt access earthworms or dung beetles.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-5) Examples of milk spot liver! I think itโs super pretty 
๐๐จ๐ฎ๐ซ๐๐๐ฌMaxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Ballweber, L.R. Ascaris suum in Pigs. Merck Veterinary Manual 2015.
Photos 1-5 courtesy of Noahโs Arkive.
