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.     

An epizootic of hemorrhagic disease in white-tailed deer in Missouri

As part of a white-tailed deer (Odocoileus virginianus) survival study in Missouri (USA) we were actively monitoring 97 radio-collared deer when 8 (8%) died. This mortality, which occurred from 20 August to 23 September 1996, consisted of five adult females, two yearling females and one yearling male. Based on the seasonality of this mortality and the isolation of epizootic hemorrhagic disease virus (EHDV) serotype 2 from one of these animals, we believe that these losses resulted from an epizootic of hemorrhagic disease. The remains of five unmarked deer that may have died from HD also were found on the study area during this same period. During the fall following this mortality, we tested serum from 96 deer taken by hunters in the immediate area. Fifteen (16%) were positive for EHDV or bluetongue virus (BTV) antibodies as determined by agar gel immunodiffusion tests. Serum neutralization test results indicated that previous infections were caused by EHDV virus serotype 2. Based on these data, and assuming that there was no prior exposure to EHDV serotype 2 in this population, the exposure rate for this epizootic was 24% of which 8% died. We noted hoof interruptions in only two of the 96 deer sampled. During this mortality event, the Missouri Department of Conservation received no reports of dead deer, and without the radio-monitored animals the event would have been undetected.     

Serologic survey of selected pathogens in white-tailed and mule deer in western Nebraska

Exposure of free-ranging white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in western Nebraska to selected livestock pathogens was determined by serology and attempted virus isolation. Antibodies to bluetongue virus, epizootic hemorrhagic disease virus, and bovine respiratory syncytial virus were present in both species of deer. No serologic reactors to Brucella or Anaplasma were found. Attempts to isolate bluetongue virus were negative.     

Disease survey of free-ranging grey brocket deer (Mazama gouazoubira) in the Gran Chaco, Bolivia

Samples from 17 free-ranging hunter-killed grey brocket deer (Mazama gouazoubira) in the Gran Chaco, Bolivia, were collected during June-August 1999. All 17 deer appeared to be in good condition at the time of death. Gross necropsies were performed, serum was collected for serologic evaluation of selected infectious disease agents, and feces and ectoparasites were collected for evaluation of internal and external parasites. Serologic tests were positive for antibodies against bovine respiratory syncytial virus and four Leptospira interrogans serovars, with questionable results for epizootic hemorrhagic disease virus serotypes 1 and 2. No antibodies were detected to Anaplasma marginale, Babesia bigemina, Babesia bovis, Babesia odocoilei, bluetongue virus (serotypes 2, 10, 11, 13, and 17), bovine viral diarrhea virus, Brucella abortus, foot-and-mouth disease virus, infectious bovine rhinotracheitis virus, Mycobacterium avium subsp. paratuberculosis, and parainfluenza-3 virus. Sixty-four percent (7/11) of the deer had endoparasites. Amblyomma spp. ticks were found on seven deer, flies of the family Hippoboscidae on six deer, and lice on six deer.     

Serosurvey for selected infectious disease agents in free-ranging black and white rhinoceros in Africa

Two hundred and eighty one serum samples collected from free-ranging black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros, in the Republic of South Africa (RSA), Namibia, and Kenya from 1987-97, were examined for antibody to 16 different infectious agents. Positive antibody titers were detected against Akabane (59.8%), bluetongue (55%), African horse sickness (27.9%), epizootic haemorrhagic disease of deer (19.4%), parainfluenza type 3 (25.3%), bovine herpes virus 1 (3.1%), equine herpes virus 1 (8.8%) and bovine viral diarrhea (1.2%) viruses, and four serovars of Leptospira interrogans, (ranging 1.2 to 8.8%). No antibody was detected against Rift Valley fever virus, encephalomyocarditis virus, Brucella abortus, and Trypanosoma equiperdum. Interspecies differences were detected for African horse sickness, epizootic haemorrhagic disease of deer and parainfluenza type 3 viruses. There appeared to be some geographic variation in the prevalence of antibody for African horse sickness, bluetongue, epizootic haemorrhagic disease of deer, parainfluenza type 3, equine herpes virus 1 and Leptospira interrogans serovar bratislava.     

Serological survey for potential disease agents of free-ranging cervids in six selected national parks from Germany

A total of 164 blood samples, collected from free-ranging red deer (Cervus elaphus), roe deer (Capreolus capreolus) and fallow deer (Dama dama) in six German national parks (NP) between 2000 and 2002, were assayed for antibodies against nine viral disease agents. Antibodies were only detected against the alpha-herpesviruses; specifically, bovine herpesvirus-1 (BHV-1) (22 of 157, 14%), cervid herpesvirus-1 (17 of 157, 10.8%), and caprine herpesvirus-1 (11 of 159, 6.9%). Titers ranged from 4 to 102. Most of the seropositive sera, and those with the highest antibody titers, were from red and roe deer in the Harz and Hochharz NP, which are connected and allow migration between the two. The distribution and specificity of antibodies detected in individual deer suggests that the three alpha-herpesviruses are circulating in these deer populations. No antibodies were detected against bovine viral diarrhea virus, epizootic hemorrhagic disease virus, bovine leukemia virus, bluetongue virus, foot-and-mouth disease virus, or sheep and goat poxvirus.     

Modoc-like virus isolated from wild deer mice (Peromyscus maniculatus) in Alberta

Small mammals were trapped in northeastern Alberta, Canada during 1976. Blood samples from these animals were tested for virus by inoculation of suckling mice. Blood clots from two deer mice yielded isolates of the same virus. The virus was related antigenically to a number of flaviviruses which have been isolated from mammals in Central America and North America and was related most closely to Modoc virus. Physical, chemical, and biological properties of the virus were similar also to those of Modoc virus. It did not produce illness or death in deer mice inoculated in the laboratory. Neutralization tests indicated that 1/38 (3%) red squirrels (Tamiasciurus hudsonicus), 3/35 (9%) least chipmunks (Eutamius minimus), 13/109 (12%) deer mice, and 3/50 (6%) humans were infected naturally. This is the first reported evidence of infection of red squirrels and chipmunks with a Modoc-like virus. These data extend the range of Modoc-like viruses northward by 1,500 km and comprise the first isolate from mammals in the boreal forest of Canada.     

Susceptibility of white-tailed deer (Odocoileus virginianus) to experimental infection with epizootic hemorrhagic disease virus serotype 7

During the fall of 2006, in Israel, epizootic hemorrhagic disease virus (EHDV) serotype 7 caused an intense and widespread epizootic in domestic cattle that resulted in significant economic losses for the dairy industry. The susceptibility of potential North American vector and ruminant hosts to infection with EHDV-7 is not known but is essential to understanding the potential for establishment of this exotic orbivirus in North America if it were introduced. Our primary objective was to determine whether white-tailed deer (WTD; Odocoileus virginianus) are susceptible to infection with EHDV-7. Six, 8-mo-old WTD were experimentally infected with EHDV-7, and all became infected and exhibited varying degrees of clinical disease. Clinical signs, clinicopathologic abnormalities, and postmortem findings were consistent with previous reports of orbiviral hemorrhagic disease (HD) in this species. Four of six animals died or were euthanized because of the severity of disease, one on postinoculation day (PID) 5 and the remaining WTD on PID 7. All deer had detectable viremia on PID 3, which peaked on PID 5 or 6 and persisted for as long as PID 46 in one animal. Deer surviving the acute phase of the disease seroconverted by PID 10. Based on the 67% mortality rate we observed, this strain of EHDV-7 is virulent in WTD, reaffirming their role as a sentinel species for the detection of endemic and nonendemic EHDV. Further, the observed disease was indistinguishable from previous reports of disease caused by North American EHDV and bluetongue virus serotypes, highlighting the importance of serotype-specific diagnostics during suspected HD outbreaks.     

Parasites, diseases, and health status of sympatric populations of fallow deer and white-tailed deer in Kentucky

In August 1983, a study on parasites, diseases, and health status was conducted on sympatric populations of fallow deer (Dama dama) and white-tailed deer (Odocoileus virginianus) from Land Between The Lakes, Lyon and Trigg counties, Kentucky. Five adult deer of each species were studied. White-tailed deer had antibodies to epizootic hemorrhagic disease (EHD) virus and Leptospira interogans serovariety icterohemorrhagiae, and fallow deer had antibodies to bluetongue and EHD viruses. Serologic tests for bovine virus diarrhea virus, infectious bovine rhinotracheitis virus, parainfluenza3 virus, and Brucella spp. were negative. One white-tailed deer had an infectious cutaneous fibroma, and one fallow deer had pulmonary mucormycosis. White-tailed deer harbored 16 species of parasites, all of which are considered typical of the parasite fauna of this host in the southeastern United States. Fallow deer harbored nine species of parasites, including eight species known to occur in white-tailed deer on the area and one species (Spiculopteragia assymmetrica) that is not. All fallow deer had inflammatory lesions in the spinal cord and/or brain that were attributed to prior infection with meningeal worm (Parelaphostrongylus tenuis), indicating that P. tenuis infections are not always fatal for this species. The apparent high rate of exposure of Land Between The Lakes fallow deer to P. tenuis without a resultant high rate of clinical cerebrospinal parelaphostrongylosis is hypothesized to be due to a low prevalence and intensity of P. tenuis, partial innate resistance of fallow deer, and acquired immunity.     

Bluetongue in free-ranging pronghorn antelope (Antilocapra americana) in Wyoming: 1976 and 1984

At least 3,200 pronghorn (Antilocapra americana) died during a bluetongue (BT) epizootic in eastern Wyoming during late September and early October 1976. In August and September 1984, another BT epizootic occurred in northeastern Wyoming resulting in 300 known pronghorn deaths. In 17 pronghorn examined postmortem, hemorrhages and edema were the most common gross pathologic changes. Microscopic changes included hemorrhage, edema, arterial fibrinoid necrosis, lymphoid depletion in splenic and lymphatic follicles, and neuronal necrosis. Bluetongue virus serotype 17 was isolated from pronghorn in both epizootics. Mortalities ceased with the advent of cool weather in late September and October. Seventy-six of 94 pronghorn killed by hunters during the latter period of the 1976 epizootic, and 14 of 24 pronghorn killed 1 yr later had serologic evidence of exposure to BT virus. The reproductive rate in pronghorn was depressed to 47 fawns per 100 does in August 1977, but returned to 93 fawns per 100 does by 1978. Following the 1984 outbreak, the reproductive rate was similarly depressed, but the cause was confounded by other environmental and range conditions. Deer, mostly mule deer (Odocoileus hemionus), also died during both epizootics of what was presumed to be BT.     

Experimental Fascioloides magna infections of mule deer (Odocoileus hemionus hemionus).

Six mule deer (Odocoileus hemionus hemionus) and one white-tailed deer (Odocoileus virginianus), approximately 5-mo-old, each were inoculated orally with 500 metacercariae of Fascioloides magna. All mule deer died from liver fluke infection between 69 and 134 days (mean = 114, SE = 9.9) after inoculation. Between 38 and 326 immature F. magna (mean = 102, SE = 45.5) were recovered from each deer at necropsy. Flukes were present in livers, lungs, and free in pleural and peritoneal spaces. Infection was characterized by necrotizing hepatitis, fibrosing peritonitis and pleuritis, and hematin pigment accumulation in liver, lung, and many other internal organs. Eggs of F. magna first were detected in feces of the white-tailed deer 28 wk after inoculation, and weekly thereafter until the healthy deer was euthanized at 31 wk. At necropsy, 205 F. magna, including 12 encapsulated mature and 193 nonencapsulated immature flukes were recovered from liver, lungs, and free in abdominal and thoracic spaces of the white-tailed deer. Based on these results, F. magna may be fatal to mule deer within 5 mo of infection. Like domestic sheep and goats, mule deer may be highly susceptible to infection, and it is unlikely mule deer can survive infection with large numbers of F. magna.     

Parasites, diseases and health status of sympatric populations of sambar deer and white-tailed deer in Florida

From December 1983 to December 1984 a study on parasites, diseases and health status was conducted on sympatric populations of sambar deer (Cervus unicolor) and white-tailed deer (Odocoileus virginianus) from St. Vincent Island, Franklin County, Florida. Ten sambar and six white-tailed deer were examined. White-tailed deer had antibodies to epizootic hemorrhagic disease virus and bluetongue virus. Serologic tests for antibodies to the etiologic agents of bovine virus diarrhea, infectious bovine rhinotracheitis, vesicular stomatitis, parainfluenza 3, brucellosis, and leptospirosis were negative in both species of deer. White-tailed deer harbored 19 species of parasites; all were typical of the parasite fauna of this species in coastal regions of the southeastern United States. Sambar deer harbored 13 species of parasites, which apparently were derived largely from white-tailed deer. The only exception was Dermacentor variabilis which occurs frequently on wild swine on the island. The general health status of sambar deer appeared to be better than that of white-tailed deer. This was hypothesized to result from the sambar deer's utilization of food resources unavailable or unacceptable to white-tailed deer and to the absence and/or lower frequency of certain pathogens in sambar deer.     

Antibodies to bluetongue and epizootic hemorrhagic disease viruses from white-tailed deer blood samples dried on paper strips.

The feasibility of using dried blood samples for serologic testing of white-tailed deer (Odocoileus virginianus) for antibodies to bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) was tested with matched samples of serum and eluted dried whole blood. Results from matched serum virus neutralization (SN) tests indicated that a 1-ml elution from a 1- x 2-cm section of filter paper strip containing dried blood approximated a 1:10 serum dilution. Neutralizing antibody titers detected from 34 matched titrations of serum and dried blood samples were equivalent in 25 (74%) titrations and were within a single dilution in the remaining nine (26%) titrations. Eluted blood samples from SN-positive deer, however, did not produce detectable precipitin lines on agar gel immunodiffusion tests for antibodies to either BTV or EHDV. In a trial using serum and dried blood samples from 108 hunter-killed deer from five locations in Georgia (USA), antibody prevalence and serotype distribution results were similar. Use of dried blood samples for serologic testing for antibodies to BTV and EHDV provides a reliable alternative to serum but should be considered only when serum collection is not feasible.     

Antibody production in rats vaccinated with inactivated Sendai virus (author's transl)

Adult male and female rats were inoculated with tween 80-ethylether-formalin-ultraviolet inactivated Sendai virus (Sv-V) and examined for the production of hemagglutination inhibition (HI) antibody. There were no significant differences in the antibody titers between males and females, and among the various routes of inoculation except for the intranasal which was not effective. The antibody became detectable 7 days after a single inoculation with 10(5) HAU of Sv-V. The antibody titer, which had its peak 21 days after the inoculation, persisted for 200 days and declined gradually thereafter. The HI antibody titers were correlated with inoculated Sv-V doses and a predominant booster reaction with the vaccine was observed. Maternal antibodies were detected in sucklings born to dams hyperimmunized with the vaccine. The titers were similar to those of the dams until 3 weeks after birth but declined rapidly after weaning at 4-week-old. The titers of fetuses and neonates before suckling were significantly lower than those of the sucklings.     

Experimental infection of white-tailed deer (Odocoileus virginianus) with Ehrlichia chaffeensis by different inoculation routes

The infection dynamics of the tick-transmitted organism Ehrlichia chaffeensis were investigated in white-tailed deer (Odocoileus virginianus) using different routes of inoculation. Six deer were each inoculated with 5.4 x 10(6) DH82 cells infected with E. chaffeensis (Arkansas strain) by three different routes: intravenous (n = 2), subcutaneous (n = 2), and intradermal (n = 2). Two control deer were inoculated with uninfected cells. Infections were monitored for 54 days and were continued in one deer from each E. chaffeensis inoculated group for an additional 31 days. All deer inoculated with E. chaffeensis seroconverted (> or = 1: 64) and became 16S rDNA polymerase chain reaction and/or cell culture positive by post-inoculation day 15. There was no apparent (difference in susceptibility to infection between deer inoculated by different routes for the first 50 days based on detection of E. chaffeensis infection by PCR assay of blood or culture isolation. These results demonstrate infection of (deer by intradermal and subcutaneous routes for the first time.     

Shedding and intracage transmission of Sin Nombre hantavirus in the deer mouse (Peromyscus maniculatus) model

The mechanism(s) by which Sin Nombre (SN) hantavirus is maintained in deer mouse populations is unclear. Field studies indicate that transmission occurs primarily if not exclusively via a horizontal mechanism. Using an experimental deer mouse infection model in an outdoor laboratory, we tested whether infected rodents shed SN virus in urine, feces, and saliva, whether infected mice transmit infection to na?ve cage mates, and whether infected dams are able to vertically transmit virus or antibody to offspring. Using pooled samples of urine, feces, and saliva collected from mice infected 8 to 120 days postinoculation (p.i.), we found that a subset of saliva samples, collected between 15 and 90 days p.i., contained viral RNA. Parallel studies conducted on wild-caught, naturally infected deer mice showed a similar pattern of intermittent positivity, also only in saliva samples. Attempts to isolate virus through inoculation of cells or na?ve deer mice with the secreta or excreta of infected mice were uniformly negative. Of 54 attempts to transmit infection by cohousing infected deer mice with seronegative cage mates, we observed only a single case of transmission, which occurred between 29 and 42 days p.i. Dams passively transferred antibodies to neonatal pups via milk, and those antibodies persisted for at least 2 months after weaning, but none transmitted infection to their pups. Compared to other hantavirus models, SN virus is shed less efficiently and transmits inefficiently among cage mates. Transmission of SN virus among reservoir rodents may require factors that are not required for other hantaviruses.     

Transmission studies with Sarcocystis idahoensis of deer mice (Peromyscus maniculatus) and gopher snakes (Pituophis melanoleucus)

Transmission studies with Sarcocystis idahoensis of deer mice (Peromyscus maniculatus) and gopher snakes (pituophis melanoleucus) were conducted to determine host specificity of various stages of the parasite. Sporocysts were not passed by four dogs or four cats fed infected skeletal muscle from deer mice. Seven white mice (Mus musculus) and 34 white-footed mice (Peromyscus leucopus) were negative for sarcocysts and liver meronts following oral inoculation with S. idahoensis sporocysts; however, excystation of sporocysts occurred in two white-footed mice killed four hours post inoculation (PI). A gopher snake orally inoculated with sporocysts remained negative for coccidia for two months PI. Three deer mice orally inoculated and three intraperitoneally (IP) inoculated with tachyzoites from liver meronts developed sarcocysts in their skeletal muscles similar to those seen in deer mice orally inoculated with sporocysts. Liver meronts were not found. Ten deer mice orally inoculated and 10 deer mice inoculated IP with bradyzoites from S. idahoensis sarcocysts remained negative for sarcocysts and liver meronts at necropsy 17 days PI.     

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 and epizootic hemorrhagic disease virus infection in California black-tailed deer.

Four adult black-tailed deer (Odocoileus hemioneus columbianus) and five fawns were inoculated with bluetongue virus (BTV) and one adult deer was inoculated with epizootic hemorrhagic disease (EHD) virus to produce clinical signs and lesions of hemorrhagic disease. Serologic response was monitored using the agar gel immunodiffusion (AGID) test and the competitive enzyme-linked immunosorbent assay (C-ELISA). Embryonating chicken eggs and vero cells were used to detect viremia. No animal exhibited clinical or pathologic signs of hemorrhagic disease. Bluetongue viremia was detected as early as 2 days post-inoculation (DPI-2) and in some animals, persisted until at least DPI-12. The earliest detection of BTV antibodies using the AGID was DPI-8. Two adult deer remained seropositive for BTV antibodies for > 9 mo and 1 yr, respectively, using both the AGID and C-ELISA tests. We observed cross reactions between BT and EHD antibodies using the AGID tests. Also, the AGID test did not consistently detect exposure to BTV. Viremia was not detected in the deer inoculated with EHD although this animal was AGID positive between DPI-6 and DPI-49.     

Bluetongue and related viruses in New South Wales: isolations from, and serological tests on samples from sentinel cattle

Sentinel cattle at a number of localities in northern and central coastal New South Wales were sampled over the summer and autumn seasons of the years 1979, 1980 and 1981. A total of 118 orbiviruses were isolated; 99 were of the Palyam group, 15 were of the epizootic haemorrhagic disease (EHD) of deer group, and 4 of the bluetongue group. The Palyam group viruses were identified by serotype as 68 Bunyip Creek, 23 CSIRO Village, 7 D'Aguilar and one was not typed. The EHD viruses were identified as 13 type 5 and 2 type 6. All 4 bluetongue viruses were type 21. There was also convincing serological evidence that bluetongue type 1 infection occurred in 1980. Antibody to the bluetongue group, as demonstrated in a gel diffusion precipitin test, was often transient. It appeared to be mostly cross-reactive with, and induced by, other orbivirus infections, particularly those of the EHD group. Viruses of the Palyam group also seemed to be implicated in some circumstances. Where infections by viruses of the bluetongue group were demonstrated, the precipitating antibody responses to a bluetongue group antigen were not noticeably stronger than many which followed EHD virus infection. The results generally confirm previous conclusions, deduced from serological surveys, regarding the frequency of orbivirus infections, the presence of bluetongue viruses, and the transient nature of many bluetongue group antibody reactions.