Serologic evidence of arboviral infections in white-tailed deer from central Wisconsin

A survey conducted during 1979-1980 on white-tailed deer (Odocoileus virginianus) in central Wisconsin revealed serological evidence of infection by selected arboviruses. Among sera from 41 deer, antibody was detected for Jamestown Canyon virus (56%) and Bunyamwera group virus (80%), demonstrating their continuing endemic activity. Antibody for La Crosse virus, not found previously in sera from deer in central Wisconsin, also was detected (5%) in this study.     

Prevalence of antibody titers to Leptospira spp. in Minnesota white-tailed deer.

Serum samples (n = 204) from 124 white-tailed deer (Odocoileus virginianus) in northeastern Minnesota (USA) were collected from 1984 through 1989 and tested for antibodies to six serovars of Leptospira interrogans (bratislava, canicola, grippotyphosa, hardjo, icterohemorrhagiae, and pomona) using a microtiter agglutination test. Eighty-eight (43%) sera were positive at greater than or equal to 1:100 for antibodies against serovars pomona and/or bratislava; none was positive for any of the other four serovars. None of the 31 sera collected in 1984-85 was positive, whereas all 54 sera collected from 1986 through 1988 had titers of greater than or equal to 1:100. During 1989, only 34 (29%) of 119 sera had titers of greater than or equal to 1:100. Based on these results, we believe there to be wide variability in exposure of Minnesota deer to Leptospira interrogans.     

Comparison of antibodies to Leptospira in white-tailed deer (Odocoileus virginianus) and cattle in Ohio

A survey was conducted to determine the prevalence of leptospiral antibodies in sera from 248 white-tailed deer (Odocoileus virginianus) in Ohio. The sera were collected at check stations during the hunting season in 1983. The microscopic agglutination microtiter test was used to determine the presence of antibodies to Leptospira interrogans serovars pomona, icterohemorrhagiae, canicola, hardjo, and grippotyphosa. Eighteen of 248 (7.3%) serum samples had antibody titers (greater than or equal to 1:100) to at least one of the five serovars tested, with three of these samples reacting to more than one serovar. Prevalence did not differ significantly between sex or age groups. The serovar antigens reacting most frequently with serum antibodies were grippotyphosa (10 of 22, 45.5%) and pomona (eight of 22, 36.4%). Sera agglutinating with pomona antigen had higher titers (ranging from 1:200 to 1:6,400) than did sera agglutinating with the other serovars. These results were compared to results obtained from cattle tested at the Ohio Department of Agriculture Laboratories during 1983. There was a significant relationship between pomona infections detected in deer and cattle (P less than 0.05), but not with grippotyphosa.     

Serologic survey of white-tailed deer on Anticosti Island, Quebec for bovine herpesvirus 1, bovine viral diarrhea, and parainfluenza 3.

In 1985 unusual mortality was observed among the 3- to 4-yr-old white-tailed deer (Odocoileus virginianus) on Anticosti Island, Québec (Canada). A viral pathogen was suspected to be the cause of the deaths. Thus, a serologic survey for bovine herpesvirus 1 (BHV-1), bovine viral diarrhea (BVD) virus and parainfluenza-3 (PI-3) virus was conducted. We examined 396 deer sera from 1985. Results indicated that the high mortality mainly afflicted 3- to 4-yr-old deer. In 1985, 57% of deer sampled were seropositive for viral neutralizing antibodies against BHV-1. Prevalences decreased over the next 2 yr of the survey. Prevalence of antibodies against PI-3 virus, determined by hemagglutination inhibition test, remained high (82% to 84%) for the 3 yr period. No deer were seropositive for neutralizing antibodies against BVD virus during the survey period. Analysis of antibodies against BHV-1 and PI-3 viruses according to sex, age and antibody titers revealed that an epizootic BHV-1 infection occurred in 1985; PI-3 infection appears to be enzootic in Anticosti deer.     

Seroepidemiology of Anaplasma marginale in white-tailed deer (Odocoileus virginianus) from Louisiana

Antibodies to Anaplasma marginale were detected by the indirect fluorescent antibody test (IFA) in six of 331 (2%) serum samples of white-tailed deer (Odocoileus virginianus) from Louisiana. None of the serum samples were positive using the A. marginale modified rapid card agglutination test. Of the six IFA positive sera retested by the complement fixation test four sera gave anticomplementary and two gave seropositive reactions. The low A. marginale reactor rate in this white-tailed deer population was probably a reflection of the lack of cohabitation between cattle and deer and the fact that the primary arthropod vectors in Louisiana are tabanids. The validity of the indirect fluorescent antibody test for A. marginale antibodies in white-tailed deer should be evaluated.     

Antibodies to vesicular stomatitis New Jersey type virus in white-tailed deer on Ossabaw Island, Georgia, 1985 to 1989.

From 1985 to 1989, 491 serum samples were collected from white-tailed deer (Odocoileus virginianus) on Ossabaw Island, Georgia (USA) and were tested for neutralizing antibodies to New Jersey and Indiana type vesicular stomatitis viruses. Prevalence of antibodies to vesicular stomatitis New Jersey (VSNJ) virus in deer for the 5-yr period was 43%. Prevalence of antibodies differed by year (P less than 0.0001), and was dependent on age class (P less than 0.0001) and location on the island (P less than 0.0001). Of 173 deer sampled from other locations in the southeastern United States, only two had VSNJ antibody titers normally considered positive (greater than or equal to 1: 32). The positive deer were from Union County, Arkansas (USA) and Wakulla County, Florida (USA). No evidence of exposure to vesicular stomatitis Indiana Virus was observed.     

Serological prevalence and isolation of Babesia odocoilei among white-tailed deer (Odocoileus virginianus) in Texas and Oklahoma

Serum samples collected from 581 white-tailed deer (Odocoileus virginianus) from Texas and from 124 white-tailed deer from Oklahoma were tested by the indirect fluorescent antibody technique against Babesia odocoilei. Prevalence of seropositive reactors varied from site to site in both states. Prevalence rates were statistically ranked as high, intermediate or low. Deer less than 12-mo-old had a significantly lower prevalence than all other age classes.     

Infections of granulocytic ehrlichiae and Borrelia burgdorferi in white-tailed deer in Connecticut

Serum or whole blood samples, obtained from 141 white-tailed deer (Odocoileus virginianus) in Connecticut (USA) during 1980, 1991, and 1996, were analyzed to detect past or current infections of Ehrlichia phagocytophila genogroup organisms and Borrelia burgdorferi. When the BDS or NCH-1 strains of granulocytic ehrlichiae were used separately in indirect fluorescent antibody (IFA) staining methods, antibody positivity rates varied from 25 to 64% in 1991 and 1996, respectively. All 50 sera tested from 1980 collections were negative. Although percentages of sera with B. burgdorferi antibodies, as detected by an enzyme-linked immunosorbent assay, also differed (23 to 53%), there were coexisting antibodies to both bacteria in 20 (49%) of 41 sera. In tests on specificity, 19 deer sera with ehrlichial antibodies also were tested by IFA staining procedures for Anaplasma marginale antibodies; one serum with a titer of 1:5,120 to ehrlichial antigen reacted to A. marginale antigen at a serum dilution of 1:320. In parallel analyses of 69 sera, results of Western blot analyses for ehrlichial infections in deer were concordant (72% agreement) with those of IFA staining methods containing ehrlichial antigen. All positive immunoblots showed bands to peptides of the NCH-1 strain of the human granulocytic ehrlichiosis (HGE) agent having molecular masses of about 44, 105, or 110 kDa. In polymerase chain reaction (PCR) studies of blood samples from 63 deer, 11 (18%) specimens were positive for 16S ribosomal DNA of an Ehrlichia phagocytophila genogroup organism, whereas 23 (37%) samples were positive for the DNA of the 44 kDa gene of the HGE agent. White-tailed deer are exposed to different tick-borne bacteria in areas where Ixodes scapularis ticks are abundant and may, in some instances, have had concurrent infections.     

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 eizootiologyof VEE in southern Texas.     

Prevalence and isolation of Toxoplasma gondii from white-tailed deer in Alabama

Nineteen white-tailed deer (Odocoileus virginianus) from 5 counties in Alabama were examined for infection with Toxoplasma gondii. Twenty-gram samples of heart tissue were bioassayed in mice, serum was examined for T. gondii antibodies using the direct agglutination test, and sections of heart muscle were examined histologically for tissue cysts. Toxoplasma gondii was isolated from 4 of 19 (21%) white-tailed deer hearts. Antibody titers of greater than or equal to 1:50 were found in sera from 7 of 16 (44%) white-tailed deer. Histological examinations of tissue sections from white-tailed deer hearts were negative for T. gondii.     

Dynamics of maternal antibodies to hemorrhagic disease viruses (Reoviridae: Orbivirus) in white-tailed deer

Enzootic stability, potentially associated with acquired resistance and subsequent transfer of maternal antibodies, innate resistance, or both, has been hypothesized to explain the lack of reports of hemorrhagic disease (HD) in white-tailed deer (Odocoileus virginianus) from Texas. The objectives of this research were to determine the following: how long maternal antibodies to epizootic hemorrhagic disease (EHD) and bluetongue (BT) viruses persist; whether fawns from an enzootic site are naturally exposed to EHD and BT viruses while maternal antibodies are present; and whether field-challenged fawns develop clinical disease. Twelve of 52 fawns from Texas were moved to an indoor facility. All 12 (100%) were positive for maternal antibodies to EHD or BT viruses by agar gel immunodiffusion (AGID) and serum neutralization (SN) tests. Weekly monitoring demonstrated that precipitating antibodies disappeared by 23 wk of age and serum neutralizing antibodies disappeared by 17-18 wk of age. Fawns that remained outdoors in Texas were not observed with signs of HD. At 14-21 wk of age (October), 39 of 40 (98%) fawns that had remained outdoors were positive for EHD and/or BT virus antibodies by AGID and 32 (80%) had SN antibody titers to one or more of five viruses (EHDV-1, EHDV-2, BTV-10, BTV-11, BTV-17). Antibody titers to EHDV-1, EHDV-2, and BTV-11 all exceeded titers of same-age indoor fawns, suggesting recent exposure. Epizootic hemorrhagic disease viruses were isolated from seven (18%) of the outdoor fawns and all 40 remained clinically normal. Natural exposure of deer to EHD and BT viruses occurred at this site in the presence of maternal antibodies without causing disease. This may be due to acquired immunity and the subsequent transfer of maternal antibodies, but it does not exclude innate resistance as a possible factor in the enzootic stability of EHD and BT viruses at this location.     

Seroconversion rates to Jamestown Canyon virus among six populations of white-tailed deer (Odocoileus virginianus) in Indiana

The annual seroconversion of fawns, yearlings, and adult white-tailed deer (Odocoileus virginianus) to Jamestown Canyon virus (California group) was followed at six Indiana sites from 1981 through 1984. In all, sera from 1,642 deer (515 fawns, 618 yearlings, and 509 adults) were tested for neutralizing antibody to three California serogroup viruses: Jamestown Canyon, La Crosse, and trivittatus. Virtually all deer with specific neutralizing antibody showed evidence of a prior infection with Jamestown Canyon virus; only three deer showed evidence of a prior infection with only La Crosse virus and none showed evidence of an infection with only trivittatus virus. While there were no significant differences in antibody prevalence to Jamestown Canyon virus between yearling and adult deer at any site, fawns had significantly lower antibody prevalences than either of the two older age groups. Significant differences in antibody prevalence were found between northern versus southern populations of white-tailed deer in Indiana, however, no significant differences were found among the four northern populations or between the two southern populations. The mean antibody prevalences in the two southern fawn, yearling, and adult populations were 15%, 38%, and 41% respectively, while the prevalences in the four northern fawn, yearling, and adult populations were 5%, 67%, and 67% respectively. These different prevalences (northern vs. southern) correlate with the higher Jamestown Canyon virus antibody prevalence in human residents of northern Indiana (2-15%) compared to residents of southern Indiana (less than 2%) found in other studies. The significantly lower prevalence of antibody to Jamestown Canyon virus in fawns is attributed to maternal antibody protecting them from a primary infection their first summer. Yearling deer showed high rates of seroconversion following their second summer of life. These results suggest that infection of white-tailed deer in Indiana with Jamestown Canyon virus is a common phenomenon.     

Impact of BVDV infection of white-tailed deer during second and third trimesters of pregnancy

While it has been demonstrated that persistent bovine viral diarrhea virus (BVDV) infections can be established in white-tailed deer (Odocoileus virginianus) following in utero exposure in the first trimester of gestation, there is little to no information regarding the outcome of infection in later stages of pregnancy in deer. Our goal was to observe the impact of infection of white-tailed deer in the second and third trimesters of pregnancy. Five white-tailed deer in the second trimester of pregnancy and four in the third trimester were infected with a BVDV type 2 virus previously isolated from a BVDV-infected deer harvested from the wild. Infection of deer in the second trimester of pregnancy resulted in loss of the pregnancy in three of five deer. Fawns born to the two remaining deer appeared normal and were born BVDV antigen-negative with neutralizing serum antibodies against BVDV. Infection of does in the third trimester of pregnancy did not result in fetal death or persistent infection and all does gave birth to live, healthy fawns that were BVDV antigen-negative and born with antibodies against BVDV. These results, combined with those previously reported regarding BVDV infection in the first trimester of pregnancy, suggest that the impact of BVDV infection of pregnant white-tailed deer is very similar to that observed in pregnant cattle.     

Efficacy of triclabendazole against fascioloidiasis (Fascioloides magna) in naturally infected white-tailed deer (Odocoileus virginianus)

The efficacy of triclabendazole was evaluated in the treatment of naturally acquired Fascioloides magna infections in white-tailed deer (Odocoileus virginianus). Twenty white-tailed deer were captured on the Welder Wildlife Refuge (Sinton, San Patricio County, Texas, USA) and maintained in a 64 x 64 m deer enclosure. Ten deer were given a 5% suspension of triclabendazole orally at a dosage of 10 mg/kg body weight and 10 deer were given a placebo. Three wk later the deer were euthanized and examined for parasites. At necropsy 19 deer were infected. All specimens of F. magna from the tissues of the triclabendazole treated deer were dead or severely affected by the drug as indicated by changes in their size, color, movement and texture relative to those from control deer. The drug was considered 100% effective against this parasite. Adverse reactions of the deer to the drug were not observed.     

Prion protein gene heterogeneity in free-ranging white-tailed deer within the chronic wasting disease affected region of Wisconsin

Chronic wasting disease (CWD) was first identified in Wisconsin (USA) in whitetailed deer (Odocoileus virginianus) in February 2002. To determine if prion protein gene (Prnp) allelic variability was associated with CWD in white-tailed deer from Wisconsin, we sequenced Prnp from 26 CWD-positive and 100 CWD-negative deer. Sequence analysis of Prnp suggests that at least 86-96% of the white-tailed deer in this region have Prnp allelic combinations that will support CWD infection. Four Prnp alleles were identified in the deer population, one of which, resulting in a glutamine to histidine change at codon 95, has not been previously reported. The predominant allele in the population encodes for glutamine at codon 95, glycine at codon 96, and serine at codon 138 (QGS). Less abundant alleles encoded QSS, QGN, and HGS at the three variable positions. Comparison of CWD-positive with CWD-negative deer suggested a trend towards an over-representation of the QGS allele and an under-representation of the QSS allele.     

Prevalence of agglutinating antibodies to Toxoplasma gondii in adult and fetal mule deer (Odocoileus hemionus) from Nebraska

Toxoplasma gondii is an apicomplexan parasite of mammals and birds. Herbivores acquire postnatal infection by ingesting oocysts from contaminated food or water. Toxoplasma gondii infection is common in white-tailed deer, Odocoileus virginianus, but little is known about the prevalence of infection in mule deer, O. hemionus. We examined sera from 89 mule deer from Nebraska for agglutinating antibodies to T. gondii using the modified direct agglutination test (MAT) with formalin-fixed tachyzoites as antigen. Thirty-one (35%) of the samples were positive at dilutions of > or = 1:25. Samples were examined from 29 fetuses from these mule deer and none were positive in the MAT. Sera from 14 white-tailed deer from Nebraska were also examined and 6 (43%) were positive for T. gondii. Samples were examined from 5 fetuses from these white-tailed deer and none was positive in the MAT. Our results in both deer species from Nebraska are similar to studies conducted in white-tailed deer from other regions of the United States. Our findings indicate that mule deer are frequently infected with T. gondii and that mule-deer meat may be a source of human infection.     

Experimental bluetongue disease in white-tailed deer

Nine white-tailed deer and six sheep were experimentally exposed to the California BTV-8 strain of bluetongue virus. The infections were fatal for seven of the nine deer. An additional deer died from exposure to an isolate of bluetongue virus from bighorn sheep. Clinical signs and lesions of bluetongue in deer were described. The incubation period, signs and lesions of bluetongue and epizootic hemorrhagic disease of deer appear to be similar. Virus isolations were made from the blood and a variety of tissues of exposed deer and identified as bluetongue virus. Neutralizing antibodies were detected in all of the convalescent sera.     

Serologic surveillance for vesicular stomatitis virus on Ossabaw Island, Georgia

Seventeen species of mammals and seven species of birds from Ossabaw Island, Georgia, were tested for vesicular stomatitis (VS) neutralizing antibodies. Seropositive results were restricted to mammals with six of 17 species testing seropositive for VS (New Jersey type) neutralizing antibodies. Seropositive species included: raccoons (Procyon lotor), white-tailed deer (Odocoileus virginianus), feral swine (Sus scrofa), cattle (Bos taurus), horses (Equus caballus), and donkeys (Equus asinus). All tests for VS (Indiana type) were negative.     

Allozyme and mitochondrial DNA analysis of a hybrid zone between white-tailed deer and mule deer (Odocoileus) in west texas

Thirty allozyme loci and 35 mitochondrial DNA (mtDNA) restriction sites were examined in 24 white-tailed deer and 46 mule deer from a hybrid zone in West Texas. A common mtDNA genotype is shared by all of the mule deer with 67% of the white-tailed deer. At the albumin locus, 13% of the white-tailed deer and 24% of the mule deer are heterozygous, sharing alleles that are otherwise species-specific in allopatric populations; 7% of the mule deer are homozygous for the allele that is characteristic of allopatric white-tailed deer. Gene flow appears to have been bidirectional, with greater genetic introgression into mule deer. The mtDNA data suggest that matings between white-tailed and mule deer have occurred in the past. Despite evidence of genetic introgression, analysis of multilocus genotypes indicates that none of the deer examined is an F₁ hybrid. Production of such hybrids appears to be generally uncommon in North American deer; management plans that assume otherwise should be reconsidered.This work was supported by an NIH Biomedical Research Support Grant, Texas Agricultural Experiment Station Program Development and Expanded Research Awards, the Caesar Kleberg Research Program in Wildlife Ecology, and a Natural Sciences and Engineering Research Council Operating Grant.     

Immunologic and molecular identification of Babesia bovis and Babesia bigemina in free-ranging white-tailed deer in northern Mexico

The suitability of white-tailed deer (Odocoileus virginianus) as hosts for the cattle ticks Rhipicephalus (Boophilus) microplus and Rhipicephalus (Boophilus) annulatus, has been well documented. These ticks have a wide host range, and both transmit Babesia bovis and Babesia bigemina, the agents responsible for bovine babesiosis. Although this disease and its vectors have been eradicated from the United States and some states in northern Mexico, it still is a problem in other Mexican states. It is not known if wild cervids like white-tailed deer can act as reservoirs for bovine babesiosis. The purpose of this study was to determine if B. bovis and B. bigemina or antibodies against them occur in white-tailed deer in the states of Nuevo Leon and Tamaulipas, Mexico. Twenty blood samples from white-tailed deer from two ranches were collected and tested with a nested polymerase chain reaction (nested PCR) and indirect immunofluorescence antibody test (IFAT) for B. bovis and B. bigemina. Eleven samples were positive for B. bigemina and four for B. bovis by nested PCR; amplicon sequences were identical to those reported in GenBank for B. bovis (Rap 1) and B. bigemina. Results of the IFA test showed the presence of specific antibodies in serum samples. This is the first report of the presence of B. bovis and B. bigemina in white-tailed deer using these techniques and underscores the importance of cervids as possible reservoirs for bovine babesiosis.