Cutaneous herpes simplex virus infection of the guinea pig: lack of resistance to acyclovir and phosphonoformic acid after topical treatment

Small Animal Models to Study Herpes Simplex Virus Infections

Herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) are two of the most prevalent human viruses worldwide. They are known to cause a variety of diseases including genital herpes, meningitis, encephalitis, cold sores and herpes stromal keratitis. The seropositive rate for HSV-1 is around 90%, whereas for HSV-2 it remains around 20-25% for the general adult population. The infections caused by these viruses remain difficult to study because a large proportion of infected individuals are asymptomatic. Furthermore, given the neurotropic characteristics of the virus, studies aimed at understanding the complex pathogenesis in humans is difficult. As a result, animal models have been developed to understand several characteristics of HSV biology, pathogenesis, disease and host responses to infection. These models are also commonly used as the first evaluation of new drugs and vaccines. There are several well-established animal models to study infection with HSV, including mice, guinea pigs and rabbits. Variables within the animal models depend on the species of animal, route of infection, viral strain, dosage, etc. This review aims at summarizing the most commonly used animal models to study HSV pathogenesis and therapies.

Phosphonoformate (foscarnet, PFA) versus trifluorthymidine in the treatment of keratitis dendritica in the human. A double-blind, randomized, preliminary trial

Twenty patients with dendritic keratitis were treated in a double-blind analysis study with either phosphonoformate 3% or trifluorthymidine 1% drops. Nineteen cases were virologically confirmed. Follow-up was performed until closure of the corneal lesion was registered and a pair comparison between both substances was made. Healing time was longer for phosphonoformate (7.16 days) than for trifluorthymidine (5.83 days). There was no significant difference between phosphonoformate and trifluorthymidine. One drug failure was registered in each series. No side effects were observed.

Antiviral effects of phosphonoformate (PFA, foscarnet sodium)

This article describes the antiviral properties of foscarnet (trisodium phosphonoformate) at the enzyme level as well as in cell cultures and in vivo. The mechanism of action against herpesvirus DNA polymerases and reverse transcriptases is outlined. Clinical studies using topical foscarnet against mucocutaneous herpes simplex virus infections are presented. The clinical use of intravenous foscarnet against severe viral infections caused by cytomegalovirus, hepatitis B virus and human immunodeficiency virus is discussed.