Efficacy of oral supplementation with L-lysine in cats latently infected with feline herpesvirus

Abstract

Once daily oral administration of 400 mg of L-lysine to cats latently infected with FHV-1 was associated with reduced viral shedding following changes in housing and husbandry but not following corticosteroid administration. This dose caused a significant but short-term increase in plasma L-lysine concentration without altering plasma arginine concentration or inducing adverse clinical effects.

Feline herpesvirus

“…loss of appetite and nervous withdrawal) to re-housing than those that did not shed; and (iii) had a trend towards lower mean serum antibody levels (as assessed by antibody/complement lytic capacity) prior to re-housing compared to the non-shedder cats [36,40]. There is also some evidence of a refractory period after an episode of viral reactivation when animals are less likely to shed [29,30,80].…”

“…L-lysine is an antagonist of arginine, which has been shown to be essential for human herpes simplex virus and FeHV-1 replication [80]. Treatment with L-lysine therefore decreases viral proteosynthesis and has been shown to have some inhibitory effect against both human herpesvirus and FeHV-1 infection.…”

“…Treatment with L-lysine therefore decreases viral proteosynthesis and has been shown to have some inhibitory effect against both human herpesvirus and FeHV-1 infection. Oral supplementation with L-lysine reduces the severity of experimentally-induced FeHV-1 conjunctivitis when administered prior to primary infection [127] and the number of shedding episodes associated with reactivation of latent infection induced by re-housing [80]. It may therefore be of use early in acute disease or as a means of reducing the severity of disease and virus shed at times of stress: suggested dosage regimens are described elsewhere [82,128].…”

“…The effect of L-lysine on FeHV-1 replication has recently been explored both in vitro and in experimental cat studies [79,80,127]. L-lysine is an antagonist of arginine, which has been shown to be essential for human herpes simplex virus and FeHV-1 replication [80].…”

Opinion of the Scientific Panel on Additives and Products or Substances used in Animal Feed on the safety and efficacy of L-lysine sulphate (Vitalys®Liquid and Dry) for all animal species

“…(Flodin, 1997) In the cat, high doses of L-lysine (0.4 -0.5 g additional L-Lys per day; i.e. increase of around 0.5 -0.6 % of dietary lys) seem to reduce severity of conjunctivitis caused by feline herpes virus type 1 (FHV-1) and virus shedding (Maggs et al, 2000(Maggs et al, , 2003Stiles et al, 2002). It is assumed that arginine has a growth promoting effect on FHV-1 and herpes simplex which will be diminished by excess dietary lysine due to the interaction between Arg and Lys (Tankersley, 1964;Maggs et al, 2000), however without affecting the plasma arginine concentrations (Stiles et al, 2002;Maggs et al, 2003;Fascetti et al, 2004).…”