Insights from a Feline Disease Could Illuminate Long COVID Understanding

Feline infectious peritonitis (FIP), a severe and often fatal disease affecting cats, is caused by a type of coronavirus similar to those responsible for illnesses in humans. Research from the University of California, Davis, has revealed that the disease mirrors some of the long-term immune challenges faced by individuals recovering from COVID-19.

In a study published in Stem Cells Translational Medicine, scientists discovered that a combination of mesenchymal stromal cell (MSC) therapy and antiviral medications significantly aided in the recovery of cats suffering from FIP. The findings suggest that studying FIP could provide valuable insights into the long-term immune dysfunction observed in some COVID-19 patients.

According to Amir Kol, an associate professor in the Department of Pathology, Microbiology, and Immunology at UC Davis, the research indicates that MSC therapy not only mitigates acute inflammation but may also help restore the immune system to a healthier state over time.

The typical feline coronavirus initially affects intestinal cells, resulting in mild gastrointestinal issues. However, in certain cats, a combination of genetic predispositions and environmental triggers can lead to a more severe form of the virus that infects immune cells, causing systemic spread. This can manifest as either wet FIP, characterized by fluid accumulation in the abdomen or chest, or dry FIP, where organ inflammation occurs without fluid build-up. Both types lead to various complications, including fever and a decrease in crucial immune cells, impacting approximately 2% of cats, particularly those in shelters.

Historically, FIP was considered untreatable until 2018 when researchers identified an antiviral drug, GS-441524, that effectively cured cats with the condition. Despite this breakthrough, the drug was not commercially available until recently, limiting treatment access.

Longitudinal studies on cats post-recovery from FIP have been sparse, but preliminary observations indicate that many still present with enlarged lymph nodes, suggesting ongoing immune activity. This phenomenon bears resemblance to the experience of some individuals with long COVID, who continue to face health challenges despite recovering from the initial infection.

In their clinical trial, researchers divided cats into two groups: one receiving antiviral treatment along with MSC infusions, and the other receiving antiviral therapy with placebo infusions. While all subjects survived due to the efficacy of the antiviral agent, those treated with MSC exhibited notable immune recovery compared to their counterparts.

The outcomes indicated a reduction in hyperactive T and B cells, which can lead to immune overdrive, alongside an increase in regulatory T cells that help modulate the immune response. Additional assessments confirmed that MSC therapy supported the recovery of exhausted immune cells, potentially aiding in the formation of long-lasting memory cells crucial for future immune defense.

The study concluded that the MSC treatment appeared safe with no significant adverse effects reported. The implications extend beyond feline health, offering a unique perspective on similar viral infections in humans, like COVID-19.

Research into animal diseases can provide important insights into human health, emphasizing the value of veterinary medicine as a platform for translational science that benefits both animals and people.