There is one frustrating cat disease that I came across quickly in Singapore. Lizard poisoning. As the name suggests the cat catches it after it digested a lizard infected with a liver fluke. While there are different flukes like Platynosomum ssp or Opisthorchis felineus, in subtropical regions Platynosomum ssp appears to be the main culprit. The fluke migrates and reproduces in the biliary system leading to severe inflammation and damages along the bile ducts in the liver, the gallbladder and the common bile duct. The challenging part about Lizard poisoning is that it won't cause any symptoms before the disease is advanced. This means, once the cat becomes sick some damages might not be reversible. The clinical signs can be very unspecific like not thriving, not eating or the cat presents in liver failure with severe icterus. The diagnosis might be revealed by finding fluke eggs in the faeces or bile, but it can be very challenging at times. The therapy involves killing the liver fluke, reducing the inflammation and increasing the bile flow as best as possible. Till today the best treatment option is the off label use of a high dose of a dewormer, called Praziquantel. While lower dosage and other medications might reduce the egg amount, new studies are showing the fluke burden did not improve. Further, the medication takes weeks to improve the liver functions and some changes might be irreversible. This means that a cat that is in liver failure will take weeks to get better, or might not improve at all if the damage is severe and not reversible at the time of diagnosis. Some cats even require surgical decompression of the thickened common bile duct to allow the bile to flow out. In some cases, the fluke has caused such severe inflammation of biliary duct cells that this can lead to cell mutation and development of cancer. Prevention would be to avoid your cat eating any lizards. This might not feasible. No regular dewormer prevents liver fluke. Only the use of off-label high doses of Praziquantel has shown to clear the infection in some cats. However, we hope more research will bring more therapeutic options and hopefully preventative measures.
Veterinary Parasitology: A review of the cat liver fluke Platynosomum fastosum Kossack, 1910 (Trematoda: Dicrocoeliidae)
J Vet Intern Med. 2016 May;30(3):787-93, Percutaneous Ultrasound-guided Cholecystocentesis and Bile Analysis for the Detection of Platynosomum spp.-Induced Cholangitis in Cats
Vet Sci. 2018 Mar 24;5(2),Efficacy of Praziquantel in the Treatment of Platynosomum fastosum in Cats with Natural Infections.