Thanks for sharing this bit of research, Hebert. I suspect it would be very helpful for us all to be able to learn the specific viral subgroup(s) infecting our cats so we could customize their diets/meds accordingly, where possible!
I wonder if vets will eventually use this test in their practices? Best, Giselle > Message: 1 > Date: Thu, 4 Sep 2008 09:45:06 -0300 > From: hebert ferrarezzi <[EMAIL PROTECTED]> > Subject: [Felvtalk] FeLV diversity > To: <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="iso-8859-1" > > I found the following introductory paragraph of an article from The Journal > of Virology very interesting (and not excessively technical), to be posted > here. It provides some possible explanations to the differences regarding > latency period, survival time, associate malignancies and other disease > outcomes that we have witnessed, which could be related to different kinds > of FeLV viruses recognizable by means of molecular sequence comparisons: > > "Feline leukemia virus (FeLV) is a naturally occurring gammaretrovirus of > the domestic cat. FeLV is endemic in free-roaming urban domestic cats, > serological survey of which shows that at least 50% of adult animals have > been infected. The disease outcome of natural FeLV infection is variable and > rather unpredictable. Among persistently infected animals, the majority > succumb to degenerative diseases, including anemia or immunodeficiency; > however, a substantial minority develop neoplastic or proliferative > diseases, including lymphoma, leukemia, or myeloproliferative disorder. The > determinants of disease outcome in natural FeLV infection have not been > clearly defined but probably involve a combination of host, viral, and > environmental factors. While there is little doubt that the genetic > heterogeneity of the outbreeding mammalian host exerts an influence on > disease outcome, the genetic heterogeneity of FeLV in nature clearly has an > impact as well. > Like other natural retrovirus populations, FeLV is not a single genomic > species but represents a family of closely related viruses. Four natural > subgroups of FeLV (A, B, C, and T) have been described on the basis of > sequence differences in the surface glycoprotein (SU) and on receptor > interactions required for entry. > Subgroup A FeLV (FeLV-A) includes the ecotropic, weakly pathogenic viruses > that are horizontally transmitted in nature. Infection with FeLV-A is > associated with prolonged, asymptomatic persistent infection that may lead > to malignant lymphoma, typically of T-cell origin. For example, infection > with FeLV-A/61E in several studies induced thymic lymphoma in some animals > after prolonged latency for up to 2 years, but other animals remained > healthy for even longer periods of observation. FeLV-A is present in all > natural infections and gives rise to the other subgroups by envelope (env) > gene mutation, insertion, or recombination events de novo. > FeLV-B is a polytropic virus that arises by recombination with endogenous > FeLV-related sequences. The disease association of FeLV-B infection remains > unclear; however, FeLV-B is unusually common in animals with lymphoid > malignancy and thus may be linked to the induction of that disease. > FeLV-C is also a polytropic virus that arises by mutation in the SU gene. > FeLV-C is strongly associated with aplastic anemia in infected animals. > FeLV-T has recently been classified and includes T-cell-tropic cytopathic > viruses that cause lymphoid depletion and fatal immunodeficiency disease in > infected cats. FeLV-T evolves from FeLV-A by mutation and insertion in the > SU gene. > The association of particular outcomes with FeLV subgroups as described > above suggests that the nature of the virus isolate is the major disease > determinant in FeLV infection. In fact, in the case of anemia or > immunodeficiency induced by FeLV-C or FeLV-T, the genetic regions > responsible for directing disease outcome have been localized to mutations > or insertions in the FeLV SU gene. By comparison, the viral determinants of > neoplastic disease have not been as clearly defined." > Chandhasin et al. full text is available at > http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=15827142 > > Thanks for the attention, > Hebert > > > > _________________________________________________________________ > Instale a Barra de Ferramentas com Desktop Search e ganhe EMOTICONS para o > Messenger! ? GR?TIS! > http://www.msn.com.br/emoticonpack > > ------------------------------ > > _______________________________________________ > Felvtalk mailing list > [email protected] > http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org > > > End of Felvtalk Digest, Vol 3, Issue 4 > ************************************** > _______________________________________________ Felvtalk mailing list [email protected] http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org
