FeLV-homologous sequences in captive wild felid feces: infection not confirmed
Scientific reports · 2026
In plain language
The study analyzed fecal samples from 24 captive wild felids and detected genetic sequences similar to those of FeLV. This finding does not confirm latent or active FeLV infection. No link to lymphoma or leukemia was established. The findings apply only indirectly to domestic cats.
Scientific detail
Published in Scientific Reports in 2026 (doi: 10.1038/s41598-026-52077-7), this in vivo study used fecal viral metagenomics in 24 captive Panthera individuals: 14 Amur tigers, 2 South China tigers, 4 African lions, 3 leopards, and 1 jaguar. The FeLV-relevant observation was the detection of FeLV-homologous gammaretroviral sequences in fecal metagenomes. This detection does not confirm latent or active FeLV infection.
The authors attribute the eukaryotic metabolic pathways dominating the RNA dataset to co-extracted host mRNA rather than direct viral manipulation of host metabolism. This is the authors' interpretation of the background signal, not an independently validated mechanism. These pathway annotations do not establish FeLV-driven metabolic changes or oncogenesis. This claim has evidence level D, reflecting the indirect applicability of findings in wild Panthera felids to domestic cats.
The cohort was small, opportunistically selected, and drawn from a single facility, limiting generalizability. The animals were asymptomatic, and their health status was assessed solely through physical observation. The absence of concurrent diagnostic testing prevents distinction between transient shedding, latent carriage, and subclinical active infection. No control group was reported. Omission of host rRNA/mRNA depletion introduced transcriptomic background and likely reduced sensitivity for low-abundance RNA viruses.
Whether the detected FeLV-homologous sequences represent latent FeLV infection remains unresolved. The authors propose this possibility in the discussion but acknowledge that the available diagnostic data cannot determine infection state. The study does not establish an association with lymphoma or leukemia and does not investigate FeLV-driven oncogenesis.
What we know
FeLV-homologous gammaretroviral sequences were detected in fecal metagenomes from captive wild felids. The authors interpret the eukaryotic metabolic pathways dominating the RNA data as arising from co-extracted host mRNA, not direct viral manipulation of metabolism. This interpretation is not an independently validated mechanism; its evidence level D reflects indirect applicability to domestic cats.
What we don't know
Whether the detected sequences represent latent FeLV infection remains unresolved. Active infection is also not confirmed: without concurrent diagnostic testing, transient shedding, latent carriage, and subclinical active infection cannot be distinguished. No link to lymphoma or leukemia is established, and FeLV-driven oncogenesis was not investigated.
Evidence
EvidenceLevel D — Indirect evidence: other species or retrovirusConfidence 100/100
The authors attribute the eukaryotic metabolic pathways dominating the RNA dataset to co-extracted host mRNA rather than direct viral manipulation of host metabolism.
Excerpt verified in the source — verbatim, in the source's own language“Conversely, the eukaryotic pathways dominating the RNA dataset (such as energy and arachidonic acid metabolism) simply stem from host mRNA co-extracted during our total nucleic acid protocol. Rather than indicating any direct viral manipulation of host metabolism, these signals reflect the typical shedding of feline epithelial and immune cells into the gut lumen 24 – 26 .”
This records the authors' interpretation of the background signal, not an independently validated mechanism. These pathway annotations do not establish FeLV-driven metabolic changes or oncogenesis. Level D reflects indirect applicability from wild Panthera felids to domestic cats.
The discussion proposes possible latent infection but acknowledges that available diagnostic data cannot resolve infection state. Neither latent infection nor a connection to lymphoma or leukemia is established.
Provenance
Source: Diversity of fecal viromes and zoonotic risk assessment in captive wild felids using viral metagenomics.
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