Hamster Polyoma Virus Information Page

Bewteen 2000 and 2003 there was an epidemic of hamster polyoma virus infecion in the UK. We are very fortunate to have Dr Liz Johnson, a veterinary research graduate from Glasgow Veterinary School to advise and inform us. I have collected various articles from the hamster journals over this time and these are presented here. For the definitive guide, I suggest the reader refer to the article in the BHA journal January 2002

 A commentary on the infection was received from Dr Aiden Foster from the Bristol School of Clinical Veterinary Science.

Articles on the virus have been published in recent BHA journals:

 A Response to last month's internet gleaning on Papova by Liz Johnson

 Lumps - a response by Joanna Roach

 Papovavirus - an update by Anne Dray

 An early account of the infection by Anne Dray

Further information from the NetVet site has been submitted by Jessica Penther.
NetVet article

Re: Papovavirus Update

I have had some provisional results from Germany which are similar to previous in that there is some reactivity to the papovavirus antigens but not the main antigen. The tests are being repeated and when I get the final results I hope to draft an abstract for a conference and for publication. This still leaves us with no DEFINITIVE proof that the papovavirus is the cause of skin nodules or the spread of the disease.

In some respects the vet is correct in suggesting that we have to live with the situation.

Since the outbreaks behave like an infection one has to adopt the usual precautions of trying to limit the spread of any infectious disease. That is, try to reduce handling of affected or in-contact animals. Wash hands and use gloves between handling animals. Keep stocking densities low to avoid cross contamination via urine of the bedding and animals. Only the local vets can really comment on such measures because in part they are based on the knowledge of the individual hamster owner's accommodation.

If nothing else this problem has highlighted the need to secure a close working relationship with local vets to carry out (albeit potentially expensive) tests including skin biopsies and post-mortems to try to establish causes for skin nodules or sick animals. Not all nodules are going to be of the kind associated with papovavirus and without a histopathology report one can only speculate. Those hamsters that have fallen ill/died with such nodules may have disease unrelated to the suspected papovavirus.

Similarly if the pattern of the disease should change and the internal tumour form of the disease should be reported (called lymphoma) then we are potentially going to have deaths. Potentially whole colonies would need to be considered for euthanasia. This reflects the experience of research colonies where once established the diseases becomes endemic and there is no way of preventing spread.

Since urine is considered to be the source of the virus the showing of animals requires careful consideration of handling and hygiene.

Dr Aiden P Foster
Bristol School of Clinical Veterinary Science

Papova Virus

We are now aware of 4 Hamsteries that have almost certainly been infected by a highly infectious virus called a papovavirus. We did believe that the original notification that we received of the occurrence of this virus in the West Country was an isolated case but the other suspected cases are in the Midlands and the Yorkshire Areas.

The infection has been associated with the development of skin nodules that look like warts. The nodules are found particularly around the face but may involve the whole skin of hamsters. The limited information that we have to date is that the virus is transmitted via urine. This means that it can be spread by cage litter being kicked out into other cages, the same scrapers being used, handling several hamsters without washing hands or wearing gloves, etc. We understand that this virus is specific to Syrian and European Hamsters and that other species of hamsters or other animals are unaffected and cannot carry the virus.

Historically the virus has been associated with internal tumours (lymphoma). The lymphoma may take 5-30 weeks to develop following infection. The lymphoma disease is usually fatal. Please note that the case material from the West Country has not been associated with the lymphoma form of the disease.

Affected animals in the more advanced stages of the disease show warts around the face but earlier in the progression of the disease if the skin on the scruff of the neck is rubbed between the fingers then small grains can be felt whereas normally nothing is felt. Unlike true papillomas (warts) the skin lesions do not appear to regress, and there is no evidence, to date, to support the use of wart vaccines.

The case material seen in the West Country is the subject of on-going studies with the local vets and a research group in Germany. They are attempting to confirm that papovavirus is involved in this disease.

Them is no information about effective treatments and papovavirus infection can become endemic within a colony. Until we have better information about how to avoid the spread of this disease we would urge members to minimise the movement of stock and particularly ask members who have not imported new stock to their hamsteries or attended shows since last summer to please keep their stock isolated for the time being.

If anyone believes they have affected stock it would be very helpful if they could contact myself to register this fact and for them to advise anyone that has had stock from them. We need complete honesty about the extent of this disease if we are to prevent It becoming widespread.

Anne Dray
BHA Secretary
(published in 2000)

Transmissible Lymphoma

Publication Date unknown - more information may be available at www.netvet.com

  1. Cause : a unique mammalian viroid has been proposed as the cause by Coggin et al.; however, recent evidence indicates that the actual cause may be a papovavirus.
  2. Epizootiology: More than half of the hamsters 1 to 21 days old exposed in Coggin's facilities developed lymphoma. (Between 1975 and 1979, there were 3,749 individual cases.) Coggin et al. have described several epizootics among their hamsters, and epizootics also have occurred elsewhere. Transmission is by direct animal to animal contact, aerosol or ingestion of dried cage litter containing urine and feces. In Coggin's colony, it was common for more than 25% of newly introduced hamsters to die of diarrheal disease within 5 weeks after exposure to hamsters carrying the lymphoma agent. Coggin's hamsters also had enzootic papovavirus infection.
  3. Clinical: Emaciation, weakness, lethargy, diarrhea, rectal and abdominal bleeding, and subcutaneous masses. Papillomas also occur in infected colonies.
  4. Pathology: Most lymphomas arise in the large and small intestine and mesenteric nodes. Other affected organs, in approximate descending order of frequency, include liver,kidney, thymus, cervical lymph nodes, perirenal lymph nodes, stomach, eye, and inguinal lymph nodes. Most lymphomas are of B-cell origin, although some are T-cell, and most are composed of immature lymphoid cells, with rare to frequent mitotic figures. Some tumors are more pleomorphic, and some were classified as plasmacytomas. The cause of the diarrhea is not apparent from published descriptions; intestinal lesions are characterized as "nonbacterial." In young animals there is watery intestinal content with intussusceptions in a few hamsters; in adults hemorrhagic enteritis is common and many affected hamsters have intussusceptions. Papillomas are histologically typical.
  5. Diagnosis & control: Demonstration of the causative agent is difficult; lymphoma cells are not permissive for papovavirus replication and no virions are produced. Viral DNA is present in these cells, but in very small amounts, and it is difficult or impossible to detect. The papillomas, however, do contain demonstrable virus. The agent is very resistant and easily transmissible, making control difficult.
  6. References:
    Ambrose KR, Coggin JH Jr. 1975. An epizootic in hamsters of lymphomas of undetermined origin and mode of transmission. J Natl Cancer Inst 54:877-880.

    Barthold SW et al. 1987. Further evidence for a papovavirus as the probable etiology of transmissible lymphoma of Syrian hamsters. Lab Anim Sci 37:283-288.

    Coggin JH Jr et al. 1978. Horizontally transmitted lymphomas of Syrian hamsters. Fed Proc 37:2086-2088.

    Coggin JH et al. 1981. Unusual filterable oncogenic agent isolated from horizontally transmitted Syrian hamster lymphomas. Nature 290:336-338.

    Coggin JH Jr et al. 1983. B-cell and T-cell lymphomas and other associated diseases induced by an infectious DNA viroid-like agent in hamsters (Mesocricetus auratus). Am J Pathol 110:254-266.

    Coggin JH Jr et al. 1985. Papovavirus in epitheliomas appearing on lymphoma-bearing hamsters: lack of association with horizontally transmitted lymphomas of Syrian hamsters. J Natl Cancer Inst 75:91-97.

    Graffi A et al. 1968. Cell-free transmissible leukosis in Syrian hamsters, probably of viral etiology. Brit J Cancer 22:577-581.

    Graffi A et al. 1968. Virus-associated skin tumors of Syrian hamsters: preliminary note. J Natl Cancer Inst 40:867-873.

    Graffi A et al. 1969. Induction of transmissible lymphomas in Syrian hamsters by application of DNA from viral hamster papovavirus-induced tumors and by cell-free filtrates from human tumors. Proc Natl Acad Sci USA 64:1172-1180.

    Graffi A et al. 1969. Studies on the hamster papilloma and the hamster virus lymphoma. Comp Leukemia Res Bibl Hematol 36:293-303.

    Manci EA et al. 1984. Lymphoma-associated ulcerative bowel disease in the hamster (Mesocricetus auratus) induced by an unusual agent. Am J Pathol 116:1-8.

    Scherneck S et al. 1979. Studies on the DNA of an oncogenic papovavirus of the Syrian hamster. Virology 96:100-107.

    Vasa-Thomas KA et al. 1977. Characterization of immune responses to spontaneous hamster lymphomas. J Natl Cancer Inst 58:1287-1293.