Hamster polyomavirus (HaPV)
Source: Merck Veterinary Manual (merckvetmanual.com), a copyrighted professional veterinary reference. Per COPYRIGHT_POLICY §3, the points below are paraphrased derived fact summaries: numerical values and proper nouns are preserved from the source, but sentences are rewritten and not quoted verbatim.
Claims
*[Paraphrased derived summary — non-Open-Access source.]* Hamster polyomavirus (HaPV) causes outbreak (epizootic) lymphoma in young Syrian hamsters and skin epitheliomas in older hamsters carrying the infection. *[Paraphrased derived summary — non-Open-Access source.]* When HaPV enters a previously unexposed breeding colony of Syrian hamsters, lymphoma spreads rapidly, affecting up to 80% of animals (Merck cites reference 2).