The Lucke Frog Kidney Tumor and its Herpesvirus

Northern leopard frogs are afflicted with a spontaneous malignantneoplasm of the mesonephros. A herpesvirus is invariably associatedwith tumors obtained from frogs hibernating 30 days or longerand in tumors of frogs taken from breeding ponds. Tumors obtainedfrom prehibernating frogs do not have viruses as detected byelectron microscopy but virus particles are found in some tumorswithin 7 days after the onset of hibernation. Tumors of frogsmaintained at warm temperature in the laboratory do not haveviruses and tumors of frogs maintained at cold temperaturesin the laboratory do contain viruses. However, the productionof viruses in the laboratory follows a distinctly slower chronologythan that which occurs in nature. Injection of cell fractionscontaining the herpesvirus into frog embryos induces tumorsnear the time of metamorphosis in many experimental animals.Embryos injected with tumor extracts not containing herpesvirusesdo not develop tumors. Environmental and laboratory observationsare discussed which may relate to natural transmission of thispresumed viral oncogenic agent.     

Herpesviruses in Metastatic Lucké Renal Adenocarcinoma

The etiologic agent of the renal adenocarcinoma of leopard frogs, Rana pipiens , is the Lucké tumor herpesvirus (LTHV). The virus is easily detected with thin section electron microscopy in primary tumors of frogs which have been exposed to a cold environment. Several spontaneous metastatic nodules and a large primary tumor were detected at autopsy of a frog which had been maintained at 4°C for 73 days. LTHV was found not only in the primary tumor, as previously reported, but also was present in metastatic tumor cells in the liver, fat body, and bladder. The presence of LTHV in metastatic cells demonstrates that the differentiated state of primary Lucké tumor cells is retained in its metastatic colonies even at the fine structure level revealed by electron microscopy.     

The Distribution of Burnsi and Kandiyohi Frogs in Minnesota and Contiguous States

This paper contains new data and maps concerning distributionof the burnsi and kandiyohi pigment pattern variants of thenorthern leopard frog, Rana pipiens.