Research collaborative groups from Hong Kong and China have recently discovered previously unrecognized morbilliviruses in cats. This molecular epidemiological study in stray cats from Hong Kong and sick cats from mainland China identified the novel morbilliviruses and demonstrated that the viral infection has a strong association with tubulointerstitial nephritis, the most common characterization of chronic kidney disease in cats.
The new virus, named feline morbillivirus (FmoPV), is an enveloped, negative-sense single-stranded RNA virus belonging to the Paramyxoviridae family, subfamily Paramyxovirinae. Other viruses of this subfamily are associated with a number of diseases in humans and mammals including human measles, human mumps, human parainfluenza pneumonia, human respiratory syncytial virus bronchiolitis and pneumonia, phocine distemper (seals), canine distemper (dog), Newcastle disease virus (birds), and rinderpest virus (cattle), just to name a few. The researchers hypothesized that if such a virus were found in cats, then feline morbillivirus would likely be associated with disease in cats, since these viruses are usually pathogenic in other species.
FmoPV RNA was detected in 56 of 457 stray cats (53 urine samples, four rectal swabs, and one blood sample) using RT-PCR. Complete genome sequencing of three FmoPV strains showed a genome size of 16,050 bases, the largest morbillivirus sequenced to date. High sequence similarity and identical genome organization of the three strains suggest a single species of FmoPV and a high degree of species-specificity. FmoPV was isolated from Crandell-Rees feline kidney cell cultures and shown to cause cytopathic effects. Histological examination in two FmoPV positive cats revealed interstitial inflammatory infiltrate, tubular degeneration/necrosis in kidneys, and decreased cauxin expression in degenerated tubular epithelial cells consistent with tubulointerstitial nephritis. A case-control study showed the presence of tubulointerstitial nephritis in seven of 12 cats with FmoPV infection, and only two of 15 cats without FmoPV infection, strongly suggesting an association between FmoPV and tubulointerstitial nephritis.
It is speculated that a feline nephrotropic virus, such as FmoPV, may trigger a self-sustained immunopathological process after acute kidney insult. Further studies should be performed to ascertain the pathogenic role of this virus, and determine whether antiviral and vaccine development may be important in the prevention and treatment of chronic kidney disease in some cats.
In 2013, Winn funded a research project at Tufts Cummings School of Veterinary Medicine to investigate whether FmoPV is present in cats in New England and whether an association exists between infection and chronic kidney disease.
Reference: Woo PCY, Lau SKP, Wong BHL, et al. Feline morbillivirus, a previously undescribed paramyxovirus associated with tubulointerstitial nephritis in domestic cats. Proc Natl Acad Sci USA 2012;109:5435-5440. [Free, full text]
