Silver vine and other catnip alternatives
Our paper on catnip alternatives was published in BMC Veterinary Research on 16 March 2017.
Click here to access it for free (Open Access).
Since then, it has received quite some media attention. Within the first week, the article was accessed through the above link almost 1,500 times. It is already one of the most popular articles of BMC Veterinary Research since it was launched 12 years ago! It is wonderful that so many people are learning more about olfactory enrichment for cats and the various options they have. (Continues below the photograph.)
One of the many cats at Room 8 Cat Memorial Foundation enjoying Tatarian honeysuckle wood.
Great journalist such as Nick Stockton from WIRED (USA) and Cecile Borkhataria for The Daily Mail (United Kingdom) wrote about our research.
Lysine and feline herpesvirus 1
We have conducted a systematic review to evaluate what scientific evidence exists supporting the supplementation of lysine to prevent or treat feline herpesvirus 1 infection in cats.
"A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question. Researchers conducting systematic reviews use explicit methods aimed at minimizing bias, in order to produce more reliable findings that can be used to inform decision making." (source: Cochrane Library)
Levels of evidence
Feline herpesvirus 1 is a highly contagious virus that affects many cats. Virus infection presents with flu-like signs and irritation of ocular and nasal regions. While cats can recover from active infections without medical treatment, examination by a veterinarian is recommended. Lysine supplementation appears to be a popular intervention (recommended by > 90 % of veterinarians in cat hospitals). We investigated the scientific merit of lysine supplementation by systematically reviewing all relevant literature.
NCBI's PubMed database was used to search for published work on lysine and feline herpesvirus 1, as well as lysine and human herpesvirus 1. Seven studies on lysine and feline herpesvirus 1 (two in vitro studies and 5 studies with cats), and 10 publications on lysine and human herpesvirus 1 (three in vitro studies and 7 clinical trials) were included for qualitative analysis.
There is evidence at multiple levels that lysine supplementation is not effective for the prevention or treatment of feline herpesvirus 1 infection in cats. Lysine does not have any antiviral properties, but is believed to act by lowering arginine levels. However, lysine does not antagonize arginine in cats, and evidence that low intracellular arginine concentrations would inhibit viral replication is lacking. Furthermore, lowering arginine levels is highly undesirable since cats cannot synthesize this amino acid themselves. Arginine deficiency will result in hyperammonemia, which may be fatal. In vitro studies with feline herpesvirus 1 showed that lysine has no effect on the replication kinetics of the virus. Finally, and most importantly, several clinical studies with cats have shown that lysine is not effective for the prevention or the treatment of feline herpesvirus 1 infection, and some even reported increased infection frequency and disease severity in cats receiving lysine supplementation.
We recommend an immediate stop of lysine supplementation because of the complete lack of any scientific evidence for its efficacy.
The full text publication in BMC Veterinary Research is freely available via the BMC Veterinary Research website or via PubMed.