In vitro activities of 9-([2-hydroxyethoxy] methyl) guanine (acyclovir), (E)-5-(2-bromovinyl)-2'deoxyuridine, 9-beta-D-arabinofuranosyladenine (vidarabine), 5-iodo-2'-deoxyuridine (idoxuridine), and 5-trifluoromethyl-2'-deoxyuridine (trifluridine) were studied against 6 strains of feline herpesvirus-1. A significant difference was not detected among viral strains in their susceptibility to these compounds (P = 0.442). The relative potency of these compounds was trifluridine greater than greater than idoxuridine greater than virdarabine greater than bromovinyldeoxyuridine greater than greater than acyclovir. Concentrations of trifluridine and idoxuridine (0.67 and 6.8 micromole, respectively) required to reduce plaque numbers by 50%, compared with that of controls, were significantly lower (P less than 0.001) than were those of other compounds.

Serologic analyses and virus isolation studies were carried out to determine the role of bovid herpesvirus-4 (BHV-4) in infections in cattle, principally those of the reproductive tract. Serologic analyses were performed, using an indirect fluorescent antibody test on thoracic fluid specimens from aborted fetuses and on sera from 3 sources of adult cattle. Virus isolation was attempted from field cases of abortion, early embryo death, and postpartum vulvovaginitis/metritis, using uterine discharge and buffy coat preparations obtained from cows and tissues obtained from aborted fetuses. Of 420 fetal thoracic fluid specimens examined, 5 were positive for BHV-4 antibodies. Seventeen percent of adult cattle from 2 sources ie, clinically normal herds and abattoir cattle, were seropositive for BHV-4 antibodies. Cattle from a third source, 4 herds with high incidence of reproductive tract disorders, had a seroprevalence rate between 36 and 88%. Two isolates of BHV-4 were also obtained from this group. the overall incidence of BHV-4 antibodies in clinically normal cattle was higher than previously recognized, with relatively higher prevalence in herds having reproductive problems (chi-squared = 156.5, P less than 0.005). At least 10% of the BHV-4 antibody-positive sera did not have neutralizing antibody against bovine viral diarrhea virus and/or bovid herpesvirus-1, both important causes of bovine reproductive tract disorders.

A serologic survey was conducted to determine the prevalence of antibodies to alcelaphine herpesvirus-1 (AHV-1) in captive exotic ruminants within the United States. Forty-six percent of the members of the subfamily Alcelaphinae (wildebeest, topi, hartebeest) in the family Bovidae had virus-neutralizing antibody to AHV-1. Other subfamilies of Bovidae with high prevalence of virus-neutralizing antibodies to AHV-1 included Hippotraginae (oryx and addax) and Caprinae (sheep and goats), with prevalence of 45% and 29%, respectively. Herpesviruses that have been isolated from captive exotic ruminant species, including healthy animals and those with clinical malignant catarrhal fever at the Oklahoma City Zoo and the San Diego Zoo/Wild Animal Park, were analyzed by DNA restriction enzyme analysis and blot hybridization. Variation has been detected among the genomes of several malignant catarrhal fever virus isolates obtained from various exotic species of ruminants, using the DNA restriction enzymes BamHI and HindIII. The DNA of these virus isolates is distinct from that of bovine herpesviruses 1, 2, and 4, as demonstrated by restriction enzyme analysis and nucleic acid hybridization. On the basis of restriction enzyme analysis and nucleic acid hybridization data, the DNA from each of the putative alcelphine herpesvirus isolates examined, except for the topi virus isolate, had a high degree of DNA sequence similarity with the original AHV-1 isolate, WC-11, from a blue wildebeest.

Chicken eggs at embryonation day (ED) 18 or newly hatched chicks were inoculated with turkey herpesvirus (HVT), Marek's disease virus (MDV), or virus-free diluent and, at intervals after inoculation, tissue homogenates of virus-exposed and virus-free chickens or chicken embryos were examined for interferon (IFN) activity. Homogenates of lung thymus and spleen specimens from chickens given HVT at ED 18 had IFN activity. Activity of IFN in the lungs was studied further. Homogenates of lung specimens from chickens exposed to HVT at hatching also had IFN activity, although the concentration of IFN was lower than that in chickens given HVT at ED 18. The pathogenic isolates of MDV (JM-(MDV)), but not the atenuated (Md11/75C-(MDV)) or nonpathogenic (SB1-(MDV)) isolates, inoculates at ED 18 also induced high lung IFN activity. Exposure to a combination of HVT and SB1-MDV induced IFN activity comparable with that in chickens given HVT alone. The IFN activity in homogenates of lung specimens from virus-exposed chickens was species specific and heat and pH stable, but was destroyed by trypsin treatment. Occassionally, low IFN activity also was detected in homogenates of tissus specimens from virus-free chickens or chicken embryos. This IFN activity could have been produced constitutively or may have been induced by substances (inducers) in the environment.

The genetic and antigenic nature of feline cell-associated herpesvirus (FeCAHV) was characterized by use of DNA restriction endonuclease analysis, and direct and indirect fluorescent antibody (FA) techniques. Serologic responses of 6 conventionally reared cats with induced FeCAHV urinary tract infection were retrospectively evaluated, using an indirect FA test. The EcoRI, HindIII, and Pst I restriction endonuclease cleavage patterns of FeCAHV DNA were similar to those of bovid herpesvirus 4 (BHV-4; DN599 strain) DNA. Specific fluorescence was observed when FeCAHV-inoculated cell monolayers were reacted with fluorescein-conjugated BHV-4 (DN599 strain) antiserum. Conversely, specific fluorescence was also observed when feline anti-FeCAHV serum and fluorescein-conjugated caprine anti-feline IgG was reacted with BHV-4 (DN599 strain)-infected cell monolayers. At postinoculation week 10, serum antibody titer in cats with FeCAHV-induced urinary tract infection ranged from 1:2,560 to 1:10,240, as measured by use of indirect FA testing. It was concluded that FeCAHV is a member of the BHV-4 group. In addition, the FeCAHV indirect FA test provides a sensitive and specific means of evaluating FECAHV antibody concentration in exposed cats.