A marker of the FeLV virus was detected in 95 of the 428 road-killed European wildcats studied in Germany (22.2%). It was more likely to be found in adults and towards the south and west of the country. This finding does not establish disease or progressive infection, and the animals studied may not represent the wider population. It remains unknown whether the virus is maintained among wildcats or depends on transmission from domestic cats.
The study published in Viruses in 2026 (doi: 10.3390/v18060627) examined 428 road-killed European wildcats (Felis s. silvestris) collected in western and central Germany between 1995 and 2024. The sample came from Bavaria (n=26), Hesse (n=249), Lower Saxony (n=53), North Rhine-Westphalia (n=4), Rhineland-Palatinate (n=22), Saxony-Anhalt (n=4) and Thuringia (n=70). These are cross-sectional observational data, without a control group or follow-up, from opportunistic carcass sampling that may not represent the living population. The empirical claims in the knowledge object are classified as level C evidence.
FeLV antigen was detected in 22.2% of the animals (95/428). The probability of antigen detection increased from north to south and from east to west, and was higher in adults than in juveniles or subadults. The authors interpret the age association as cumulative exposure, while noting that higher mortality among young animals could also contribute. The cross-sectional design cannot distinguish between these explanations or identify the cause of the geographic gradient. Antigen detection does not establish disease or progressive infection.
No antibodies to FIV were detected in any animal. This negative result does not exclude FIV infection, because the test systems were developed and validated for domestic cats. Proximity to built-up areas did not predict seroprevalence or antigen prevalence for any virus analysed. Such proximity may be a poor proxy for domestic or feral cat density, so the result does not rule out domestic cats as the source of infection.
The authors suggest that the decline in FeLV antigen prevalence towards the northeast may reflect geographic expansion of the virus from eastern central France, and that FeLV may be sustained by transmission within wildcat populations. These are hypotheses based on comparisons with prevalence estimates from other studies, not hypotheses tested in this study. Geographic coordinates may also be confounded with unmeasured environmental gradients. Whether infection requires contact with domestic cats or is self-sustained within wildcat populations remains unresolved; distinguishing these possibilities requires transmission data and viral sequencing.
IFAT cut-offs may underestimate seropositivity. Serological surveys cannot detect active viremia or persistent infection, and provide no data on unsampled groups such as kittens. There were too few FCV-positive animals for analysis, and the FHV models had very low explanatory power. Mortality attributable to the investigated viruses has not been documented in free-ranging wildcats. Prevalence alone does not establish pathogenic impact or population-level effects.
In this opportunistic sample of 428 road-killed wildcats, FeLV antigen was detected in 95 animals (22.2%), with a higher probability in adults and towards the south and west. No antibodies to FIV were detected, and proximity to built-up areas did not predict seroprevalence or antigen prevalence for the viruses analysed. These are level C observational findings, subject to sampling limitations and the use of tests validated for domestic cats; they do not establish disease or progressive infection.
The cause of the geographic gradient is unknown, as is whether the age association reflects cumulative exposure, higher juvenile mortality or both. It remains unresolved whether FeLV is maintained among wildcats or depends on transmission from domestic cats. The extent to which the sample represents the living population, and the pathogenic or population-level impact of these infections, have not been established. The absence of FIV antibodies does not exclude infection; serological surveys cannot detect active viremia or persistent infection and provide no information on unsampled groups such as kittens.
Excerpt verified in the source — verbatim, in the source's own language“Between 1995 and 2024, 428 road-killed wildcats were collected in Western and Central Germany and stored at −20 °C until dissection.”
The sample is opportunistic and carcass-based over 30 years. It may not represent the living population.
Excerpt verified in the source — verbatim, in the source's own language“According to the most parsimonious model, adults were more likely to have FeLV antigen than juveniles or subadults.”
The authors read this as cumulative exposure, but they also note that higher mortality in young animals could contribute. The cross-sectional design cannot separate these explanations.
Excerpt verified in the source — verbatim, in the source's own language“Serological surveys cannot detect active viremia, persistent infection, or any information on unsampled groups like kittens, where mortality risk is highest for some viruses”
This is the authors' own caveat. Prevalence alone does not establish pathogenic impact or population-level effects in wildcats.
Excerpt verified in the source — verbatim, in the source's own language“the probability of having FeLV antigen increased with decreasing latitude and longitude, i.e., from north to south and from east to west”
This describes a spatial gradient in a cross-sectional dataset. It does not identify the cause of the gradient.
Excerpt verified in the source — verbatim, in the source's own language“Antibodies against FIV were not detected in any wildcat.”
This is a negative serological result in this sample. It does not exclude FIV infection, because the assays were validated for domestic cats.
Excerpt verified in the source — verbatim, in the source's own language“Proximity to built-up areas did not predict seroprevalence for any virus.”
The authors caution that built-up area proximity may be a poor proxy for domestic or feral cat density. The result does not show that domestic cats are not the source of infection.
Excerpt verified in the source — verbatim, in the source's own language“Feline leukemia virus antigen was detected in 95/428 wildcats (22.2%; 95% CI: 18.5–26.4).”
This is an observational prevalence estimate from road-killed animals, with no control group and no follow-up. It does not show disease or that the infection is progressive.
This is the authors' tentative interpretation, based on comparison with prevalence values from other studies. Coordinates may also be confounded with unmeasured environmental gradients, and the study does not test the hypothesis.
The authors state that distinguishing self-sustained infection from ongoing spillover needs transmission data and viral sequencing.
AVA