Prospects for Antiviral Chemotherapy in Veterinary Medicine: 2. Avian, Piscine, Canine, Porcine, Bovine and Equine Virus Diseases

Abstract

SummaryThis paper, which is published in two parts, reviews the literature pertaining to antiviral chemotherapy of viruses of veterinary importance. While early reports in the 1970s referred to the chemotherapy of a number of different RNA and DNA viruses, there' was considerable focus in the 1980s, initially on herpesviruses and latterly on retroviruses, and particularly in cats. Details are given of the successful treatments of FeLV and FIV, which have been used as animal models for HIV therapy. 'Therapy of equine, canine, bovine, porcine, avian, and fish diseases is also considered. The high costs of developing and registering a new chemical entity, especially for food species in which extensive toxicity/residue data are required, is the main reason why specific antiviral compounds are not currently available for veterinary use, although some non-specific immune modulators are now emerging. Concurrent availability of appropriate diagnostic tools is a prerequisite for successful veterinary antiviral chemotherapy, as is a greater understanding of the pathogenesis of virus infections in animals and the development of more sophisticated means of drug delivery, appropriate to both food animal species and companion animals (dogs, cats, and horses). Additionally, antiviral agents are valuable as research tools per se, as opposed to solely as chemotherapeutic agents. Part 1 covers the feline virus diseases, while part 2 includes the other viruses~f veterinary importance, in dogs, horses, cattle, pigs, birds, and fish.

Inhibitors of bovine herpes mammillitis virus infections in cultured cells and in vaginally infected guinea pigs

“…Toxicological questions regarding the use of this compound in veterinary animals will need to be addressed, however. Until recently, the prospects for using antiviral agents to treat veterinary diseases generally have not been encouraging (Rollinson, 1992).…”

Antiviral chemotherapy in veterinary medicine: current applications and perspectives

“…Despite this, several antivirals licensed for use in human medicine are currently used with the cascade principle in therapy for animal diseases (3); for example, idoxuridine, trifluoridine and aciclovir in cats with feline herpesvirus 1 (FeHV-1) ocular infection (4) or zidovudine against feline immunodeficiency virus (FIV) (5). At the beginning of the 1990s, state-of-the-art reviews on the use and perspectives of antiviral chemotherapy in veterinary medicine (6,7) cited several reasons for the low use of these agents in veterinary medicine:…”

“…-the high cost of development of new chemical compounds, particularly for use in food species -use restricted to a single virus and a specific animal species -difficulties encountered in development of broadspectrum antivirals with low cytotoxicity -absence of rapid diagnostic techniques allowing prompt use of a specific antiviral agent in the course of an acute infection (6,7).…”

“…The culling of millions of animals during the foot and mouth disease (FMD) outbreak in the United Kingdom in 2001 was the topic of heated debate, because of controversies around its effectiveness, the economic and ethical consequences, and the impact on public opinion (12). The use of efficient antivirals and other control measures such as vaccination has been proposed as an alternative approach to culling in the control of highly contagious diseases of livestock (7,13,14).…”

Effects of phosphonylmethoxyalkyl derivatives studied with a murine model for abortion induced by equine herpesvirus 1

“…One approach to the control of EHV-1 is the use of antiviral chemotherapy, and over the years a number of antiviral compounds have been reported to be active in EHV-1 infection models (2,3,11,12,13,14,17,18,(22)(23)(24)(25). Two compounds from the phosphonylalkyl series, (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA) and (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC), were found to be efficacious in the mouse model, modulating clinical signs, reducing virus replication in the respiratory tract, and eliminating viremia (14,16).…”