The restoration of fluids, electrolytes and the acid-base balance (e.g. replacement of losses of
potassium and bicarbonate due to salivation and reduced food intake), preferably by
intravenous administration, is required in cats with severe clinical signs. Food intake is
extremely important. Many cats with FHV infection do not eat because of their loss of smell
due to nasal congestion or because of ulcers in the oral cavity. Food may be blended to cause
less pain when eating, should be highly palatable, and may be warmed up to increase the
smell. Appetite stimulants (e.g. cyproheptadine) may be used. If the cat is not eating for more
than three days, placement of a nasal or an oesophageal feeding tube is indicated.
Antibiotics should be given to treat all acute cases of feline upper respiratory tract disease to
prevent secondary bacterial infections. Broad-spectrum antibiotics with good penetration in
the respiratory tract should be given.
Cats severely affected by FHV need intensive nursing care and appropriate supportive therapy
is very important. If there is nasal discharge, this should be cleaned away several times a day
with physiologic saline solution, and be treated afterwards with local ointment. Drugs with
mucolytic effects (e.g. bromhexine) may be helpful. Eye drops or ointment can beadministered several times a day. Nebulisation with saline can be used to combat dehydration of the airways.
Vitamins are sometimes used although their value is unclear.
Table 2.2. Antiviral drugs recommended for the treatment of acute FHV ocular disease. The drugs are listed in decreasing order of preference.
| Drug | Type of drug |
Route of administration |
Efficacy in vitro |
Effica cy in vivo |
Control led study in vivo? |
Comments |
| Trifluridine | Nucleoside analogue |
Topical Use every hour for 1st day and every 4 hours thereafter (Maggs, 2001) |
Excellent | n.d. | no | Topical treatment of choice in ocular FHV manifestations. Some cats averse to application topically. Toxic if given systemically. (Maggs, 2001) |
| Feline IFN- ω |
Interferon | Systemic 1 MU/kg SC sid or eod Oral 50,000 – 100,000 Units daily Topical dilute 10MU vial in 19ml 0.9% NaCl and use as eye drops: 2 drops in each eye 5 times a day for 10 days (Jongh, 2004). |
yes | n.d. | Safe and licensed for use in cats. No published controlled in vivo studies for use of this product in FHV infection at time of writing. Used along with l-lysine in chronic infections. |
|
| Human IFN-α |
Interferon | SC high dose PO low dose 5-35 Units daily |
yes yes |
yes yes |
yes yes |
Less bioactive than feline interferon. 5-35 Units daily reduces clinical disease but not FHV shedding. Used along with llysine in chronic infections. |
| L-lysine | Amino-acid Oral | Oral 250 mg bid or 400 mg sid |
yes | yes | yes | Safe, reduces spontaneous ocular viral shedding rate in latently infected cats (Maggs, et al, 2000; Maggs, et al, 2001; Stiles et al. 2002; Maggs et al, 2003) |
| Idoxuridine | Nucleoside analogue |
Topical use initially ever 2-4 hours (Maggs, 2001) |
excellent | n.d. | no | Topical treatment for ocular FHV. Difficult to source, pharmacists can formulate a 0.1% ophthalmic solution. Toxic if given systemically. |
| Ganciclovir | Nucleoside analogue |
Topical | excellent | n.d. | n.d. | Topical treatment for ocular FHV. Good in vitro activity against FHV (van der Meulen et al, 2006; Maggs et al, 2004) |
| Acyclovir | Nucleoside analogue |
Topical and oral | Poor (high doses may be needed to overcome viral resistance) |
some | yes | Minimal in vitro effect of all the anti-herpesvirals (van der Meulen et al, 2006, Williams et al., 2004), moderate in vivo effect (Williams et al., 2005). Marked synergy in combination with human IFN−α (Weiss, 1989). Toxic systematically. (Maggs, 2001) |
n.d. = not determined; eod = every other day; sid = once daily; bid = twice daily; tid = three
times daily.
It should be noted that the above drugs may not be readily available or licensed for cats.
Other drugs have been proposed for the treatment of FHV ocular infections, including
bromovinyldeoyuridine, cidofovir, HPMA, pencyclovir, ribavirin, valacyclovir, vidarabine,
foscarnet and lactoferrin. However, the efficacy of these drugs is not supported by appropriate
data.