Daniel O. Trainer

Polychlorinated Biphenyl: Interaction with Duck Hepatitis Virus

Ten-day-old mallard ducklings fed a polychlorinated biphenyl at concentrations of 25, 50, and 100 parts per million for 10 days suffered no apparent clinical intoxication. Five days later these birds were challenged with duck hepatitis virus, and they suffered significantly higher mortality than birds which were not exposed to the polychlorinated biphenyl.

OBSERVATIONS ON BLUETONGUE AND EPIZOOTIC HEMORRHAGIC DISEASE VIRUSES IN WHITE-TAILED DEER: (1) DISTRIBUTION OF VIRUS IN THE BLOOD (2) CROSS-CHALLENGE1

The viruses of bluetongue and epizootic hemorrhagic disease produced cell associated viremias in white-tailed deer (Odocoileus Virginianus). Highest virus titers were associated with the erythrocytes. The titers of virus in the erythrocyte fraction of blood were consistently higher than those in the leukocyte fraction, although virus persisted in both fractions for approximately the same length of time. All detectable viremia disappeared within 6 to 8 days following the development of virus-specific neutralizing antibodies. These antibodies failed to confer protection against challenge with virulent heterologous virus, although the time of death was delayed 3 to 11 days in comparison with control deer.

ARBOVIRUS SEROLOGY IN NORTH DAKOTA MULE AND WHITE-TAILED DEER1

White-tailed and mule deer sera from North Dakota were tested for the presence of neutralizing titers against 15 different arboviruses. Positive reactions in both species were obtained to eight viruses, five of which had not been previously recognized in the state. There was no significant difference (Chi square P.05) in the reactor levels of the two deer species to any of the viruses. Geographically, three of the viruses appeared to be limited to western North Dakota, while the other five were detected statewide.

Arboviruses in Reptiles: Isolation of a Bunyamwera Group Virus from a Naturally Infected Turtle

A Bunyamwera group arbovirus was isolated from the blood of a naturally infected turtle, Trionyx spinifer emoryi, from South Texas. The virus could not be distinguished by neutralization tests from either Cache Valley or Tensaw viruses. The relationship of arboviruses and reptiles is reviewed.

Serologic evidence of Venezuelan equine encephalitis in some wild and domestic populations of southern Texas.

More than 2,500 sera from approximately 30 wild and domestic species in southern Texas were tested for neutralizing antibodies to Venezuelan equine encephalitis (VEE). Virus isolations were also attempted from blood and tissue samples of many of the wild specimens. VEE neutralizing substances were present in a variety of species collected prior to the 1971 epizootic, suggesting that VEE was present and perhaps enzootic in this area before the recent epizootic. Serologic results of this study suggest that deer (Odocoileus virginianus) and feral swine (Sus scrofa) may serve as good indicators or sentinels of VEE transmission. The reservoir of VEE was not established, but results of the study suggest that a number of species or a combination of animal host populations including deer, feral swine, and peccaries (Pecari angulatus) may be involved in the epizootiology of VEE in southern Texas.

Some effects of sublethal levels of insecticides on vertebrates.

Sublethal levels of persistant insecticides are available for wildlife acquisition from many sources and are not limited to direct exposure from spraying operations. The widespread application of persistant insecticides, such as DDT and dieldrin, is common knowledge and transportation of these and other pollutants through the ecosystem has been shown to take place by both physical and biological means.’#{176}’2 Organochlorine residues have been detected in air, snow, inland and oceanic water, soil, plants and agricultural crops, as well as in a variety of invertebrates and vertebrates.’0” Residues have been detected even from such remote areas as Antarctica.” Because of the intimate dependency of wildlife on the environment, opportunity for exposure to insecticides by contact or through food chains is great.

BLUETONGUE VIRUS AND WHITE-TAILED DEER IN AN ENZOOTIC AREA OF TEXAS1

A ten-year serologic and virologic investigation into the activity of enzootic bluetongue (BT) virus was conducted in southern Texas white-tailed deer (Odocoileus virginianus texanus). Eighty-nine percent of 484 adult deer, 36% of 129 juvenile deer and 93% of 182 neonatal deer were sero-positive of BT. Antibody was not detected in fetal fawns but was found in colostrum samples. Sentinel fawn studies demonstrated that maternal antibody persists at least 8 weeks and that BT was transmitted during the fall months. The virus was isolated from a sentinel fawn but could not be recovered from deer with antibody or with organizing lesions suggestive of previous BT infection. Virus was not isolated from deer ectoparasites.

EXPERIMENTAL INFECTION IN NORTH AMERICAN ELK WITH EPIZOOTIC HEMORRHAGIC DISEASE VIRUS1

Two elk (Cervus canadensis) were inoculated intravenously with epizootic hemorrhagic disease virus. No overt signs of disease were observed in the elk although one animal had a slight febrile response. A cell associated viremia was detected in both elk, which persisted in one animal for 30 days post-inoculation. The similarities of these results to those reported for bluetongue virus infection in elk is discussed.

CARIBOU MORTALITY DUE TO THE MENINGEAL WORM (Parelapostrongylus tenuis)

Fourteen woodland caribou (Rangifer tarandus terraenovae) were released into a game reserve occupied by white-tailed deer (Odocoiles virginianus) with a high prevalence of the meningeal worm (Parelapostrongylus tenius). Within 6 months all of the caribou had succumbed to this parasite. The clinical, pathological, and epizootiological findings associated with this die-off are described.

SEROLOGIC EVIDENCE OF INFECTION OF WHITE-TAILED DEER IN TEXAS WITH THREE CALIFORNIA GROUP ARBOVIRUSES, (JAMESTOWN CANYON, SAN ANGELO, AND KEYSTONE)

Sera collected from 187 white-tailed deer (Odocoileus virginianus) from southern Texas in 1963, 1970, 1971, and 1972 were tested for the ability to neutralize several California group arboviruses. Jamestown Canyon virus was specifically neutralized by 99 of the 187 sera (53%). San Angelo and Keystone viruses were specifically neutralized by four and one sera respectively. Serologic evidence of infection of deer with California encephalitis or LaCrosse virus was not detected. Results of limited inoculation studies indicate that white-tailed deer are probably incidental, dead-end hosts for San Angelo and Keystone viruses. White-tailed deer are sensitive indicators of Jamestown Canyon virus and may be an important vertebrate host for this virus.