A new virus has been discovered in the USA that can kill domestic cats and wild cats

For the first time, a disease that can kill both domestic and wild cats has been discovered in the USA.

A variant of rustrelavirus – related to the better-known rubella virus that causes rashes in humans – called RusV was discovered last year in a mountain lioness in Douglas County, Colorado, according to a study published in the journal. Emerging infectious diseases, this month.

The big cat was observed in May 2023 with skin lesions and signs of severe muscle weakness in its hind legs. It was also reluctant to stand up and had limited mobility.

Rangers suspected the mountain lion was suffering from an illness, but were unsure of the cause of her behavior. To end her suffering and prevent brain tissue destruction, the big cat was tranquilized and shot in the chest.

The study authors then began investigating the possible cause of the unknown disease.

The scientists said examination of tissue samples, the cat’s medical history and genetic sequencing suggested that she was suffering from the Rustrela virus variant RusV. Also known as Rubivirus strelenseRusV is the cause of the so-called “staggering disease”.

Staggering disease is a usually fatal neurological syndrome in cats, the study found, and RusV was only recently identified as its cause. The animals show signs of lesions and the same limb damage.

The syndrome has been documented in domestic cats in Europe since the 1970s and has also been identified in rodents. A similar syndrome was identified in Alabama cats 45 years ago, but the cause was unclear.

To prove a connection between the lesions and RusV, the researchers used hybridization methods previously developed for the virus. Hybridization involves the combination of two complementary, single-stranded DNA molecules – the genetic material in humans and almost all organisms – or RNA molecules (ribonucleic acid). RNA is a nucleic acid in all living cells that has similarities to DNA.

Hybridization can be used to identify specific genes and analyze the concentration of the molecule messenger RNA (mRNA) in cells. MRNA molecules contain the genetic information needed to produce proteins. Proteins perform many important functions in the body, such as repairing cells and protecting the immune system.

The authors said these methods showed that RusV RNA was present in all regions of the big cat's brain and in almost all levels of the spinal cord.

“We found particularly numerous or large, point-like signals in the granule cell layer of the hippocampus and in the Purkinje cells of the cerebellum, similar to findings in frightening cases of disease in cats in Europe,” said researchers at the Friedrich Loeffler Institute in Germany.

The new RusV virus discovered in Colorado was compared with other strains. It turned out that the samples from Colorado belonged to known genetic sequences in Europe.

Scientists do not yet know how widespread the virus is among domestic cats and wild cats in the United States.

The American Veterinary Medical Association said symptoms to look out for include an unsteady gait, an inability to retract claws, extreme sensitivity to touch, tremors and convulsions. The illness usually lasts from a few days to a few weeks, but can last for more than a year.

This generally leads to a deterioration that requires the animal to be euthanized.

“We are not concerned if this is an isolated case,” said Dr. Karen Fox, a wildlife pathologist at Colorado State University and author of the study. National Geographic“However, when we traditionally discover diseases, it means that we are only the tip of the iceberg and that we have missed a whole host of other diseases over time.”