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Biomedical subjects

G M Baer

Publications and source records attributed to G M Baer.

At least 37 records · Page 2Linked to original sources
PubMed1988

Immunization of arctic foxes (Alopex lagopus) with oral rabies vaccine.

Arctic foxes (Alopex lagopus) were successfully immunized against rabies using an orally-administered, liquid SAD-BHK21 live virus vaccine in a sausage bait. Immunization was determined by serologic response and by resistance to challenge with an arctic rabies virus strain. Virus was not shed in saliva following oral vaccination, indicating that arctic foxes would not infect other foxes after ingesting this vaccine. High antibody levels were present in all experimental foxes 2 wk following initial vaccination. A booster vaccination at 56 wk induced a significant serologic response within 1 wk, suggesting an anamnestic response but titers began to decline within 8 wk in most foxes. Foxes were observed for 16 mo following the challenge and exhibited no symptoms of rabies. The SAD-BHK21 rabies vaccine in a sausage bait system has a strong potential for vaccinating wild populations of arctic fox.

Administration, Oral↗
PubMed1988

Oral administration of an attenuated strain of canine adenovirus (type 2) to raccoons, foxes, skunk, and mongoose.

An attenuated strain of canine adenovirus type-2 (CAV-2) was administered orally to 2 foxes (Vulpes fulva), 6 raccoons (Procyon lotor), a skunk (Mephitis mephitis), and a mongoose (Herpestus auropunctatus). Blood was collected weekly from the animals to monitor CAV-2 virus-neutralizing antibody titers. All animals had increases in titers. Sera from 8 foxes, 30 mongooses, 52 raccoons, and 22 skunks trapped in the field had naturally occurring antibody to CAV-2.

Adenoviridae↗
PubMed1987

Microneutralization test for rabies virus based on an enzyme immunoassay.

We have developed an enzyme immunoassay for rabies virus by using acetone-fixed infected cell cultures as the antigen. This test was used to demonstrate virus-neutralizing antibodies in human and animal sera and was as sensitive as and easier to perform than the rapid fluorescent-focus inhibition technique.

Animals↗
PubMed1987

Early antibody responses to rabies post-exposure vaccine regimens.

The aim of post-exposure rabies vaccine treatment is to induce immunity, measured as neutralizing antibody, as fast as possible. This is especially important in the tropical rabies-endemic areas where simultaneous passive prophylaxis with hyperimmune serum is not practicable in the majority of cases. We compared the rate of production of antibody during the first two weeks, by six vaccine regimens in 118 subjects using two tissue culture vaccines, human diploid cell strain vaccine (HDCSV) and purified Vero cell rabies vaccine (PVRV). No antibody was detected on day 5. On day 7, the highest seroconversion rate was seen in subjects given HDCSV intramuscularly at two sites on days 0 and 3 (7 of 15), but this was not significantly different from the group with the lowest rate: the conventional single-site intramuscular regimen. All subjects had antibody by day 14, at which time the highest geometric mean titer was in the group vaccinated with 0.25 ml doses of diploid cell vaccine given subcutaneously at eight sites. This regimen, together with the standard single-site diploid cell vaccine and an eight-site intradermal regimen of the same product gave significantly higher titers than the two-site intramuscular regimens of either product. No single immunization schedule emerges as best, so the speed of antibody response, economy, and the skill needed for intradermal injection should be considered when deciding on the optimum regimen for use in a particular geographic area.

Antibodies, Viral↗
PubMed1987

Plasma marking of arctic foxes with iophenoxic acid.

Six arctic foxes (Alopex lagopus) were marked with iophenoxic acid (IA), a substance which elevates concentrations of protein-bound iodine in blood plasma. Buccal absorption of IA was determined by placing 20 mg IA dissolved in 100% ethyl alcohol on the tongue. Blood samples collected from 1 to 36 wk following exposure showed that all foxes were marked already at 1 wk and continued until 13 wk; two foxes were still marked at 36 wk. Clearance rates for iodine varied with initial dose response, and those foxes with high 1-wk iodine concentrations excreted iodine more rapidly than those with lower initial concentrations; by 13-wk excretion rates were similar.

Alaska↗
PubMed1986

Demonstration of antigenic variation among rabies virus isolates by using monoclonal antibodies to nucleocapsid proteins.

Rabies virus isolates from terrestrial animals in six areas of the United States were examined with a panel of monoclonal antibodies to nucleocapsid proteins. Characteristic differences in immunofluorescence reactions permitted the formation of four antigenically distinct reaction groups from the 231 isolates tested. The geographic distribution of these groups corresponded well with separate rabies enzootic areas recognized by surveillance of sylvatic rabies in the United States. Distinctive reaction patterns were also identified for viral proteins from four infected bat species, and identical patterns were found in eight isolated cases of rabies in terrestrial animals. These findings suggest that monoclonal antibodies can be used to study the prevalence, distribution, and transmission of rabies among wildlife species.

Animals↗
PubMed1986

Effect of inosiplex on the humoral and cell-mediated immune responses to intradermal human diploid cell rabies vaccine.

Antigen-stimulated lymphocyte transformation was studied in recipients of intradermal human diploid cell rabies vaccine (HDCV). HDCV was administered intradermally at 8 different anatomical sites, 0.1 ml each, on day 0; followed by another 4-site injection on day 7. Rabies antigen-stimulated in vitro proliferative response was evident as early as 7 days after starting immunization. It reached a peak on day 14 and had declined by day 28. The cellular proliferative response preceded and roughly correlated with the antirabies antibody response. Simultaneous administration of inosiplex, an antiviral and immunopotentiating drug, during the first 10 days of intradermal HDCV immunization did not result in heightened antibody titres or cell-mediated immune response to the vaccine. The number of T cells and the lymphocyte proliferative response to phytohaemagglutinin in inosiplex-treated vaccinees were similarly not significantly different from untreated controls. Our results confirm other previous findings that a specific cell-mediated immune response can be consistently and rapidly induced by an intradermal regimen of HDCV immunization. The addition of inosiplex to this regimen did not enhance the humoral or cell-mediated immune responses to the vaccine. The apparent lack of immunostimulating effect of inosiplex in this setting may be the result of several factors such as the immunization schedule and the immunologic parameters examined.

Adult↗
PubMed1985

Rabies in the United States and Canada, 1983.

Primarily as a result of organized canine rabies vaccination, leash laws, and other preventive procedures aimed at the canine population, the number of rabid dogs decreased markedly in the last thirty years (Figure 10). This decrease was accompanied by a similar marked reduction in human rabies (Table 2, Figure 11). As domestic animal rabies declined, rabies in wildlife increased. Since 1958 the number of cases of rabid wildlife surpassed domestic rabies cases, and today they account for over 85% of all reported rabies cases. In 1983, a total of 5,880 laboratory-confirmed cases of rabies in the United States and its territories were reported to CDC-a decline of 398 cases compared with 1982 (7) (Table 1). The total number of cases decreased for the second consecutive year. The 13% decline in 1982 was followed by a 6.4% decline in 1983. This decrease in cases, however, was not reported by all states. The four Mid-Atlantic states--Maryland, Pennsylvania, Virginia, and West Virginia--and the District of Columbia actually experienced an 83% increase in cases. These states and the District of Columbia reported 1,903 cases in 1983 (compared with 1,040 cases in 1982) which accounted for approximately one-third (32.4%) of all rabies cases nationally.

Adult↗
PubMed1984

Human leukocyte interferon administration to patients with symptomatic and suspected rabies.

Body fluids and brain tissue from rabid human patients have demonstrated only low titers of interferon. Therefore, pharmacokinetic studies of systemically administered and locally injected leukocyte interferon were performed in 2 North American patients with suspected rabies who showed no clinically important side effects of this therapy. Similar therapy was given to 5 patients with symptomatic rabies in Europe and America. Although no prolongation of the clinical course was seen in 3 patients given high-dose intraventricular and systemic therapy, treatment was not initiated until between 8 and 14 days after symptoms were seen. The intraventricular dosage regimen produced cerebrospinal fluid levels that appeared to fall progressively over the 24 hours after injection and demonstrated good but somewhat delayed distribution into the lumbar sac. Titers produced by this therapy were 30- to 10,000-fold higher than those normally observed in this infection, however. In the patients treated at the highest dosage, a diminished and delayed antirabies neutralizing antibody titer was observed, probably a result of the administration of the exogenous interferon.

Adolescent↗
PubMed1984

Pre-exposure rabies prophylaxis: efficacy of a new packaging and delivery system for intradermal administration of human diploid cell vaccine.

The efficacy of a newly designed syringe prepacked with human diploid cell vaccine in a sufficient quantity to deliver individual 0.1 ml doses intradermally was tested by injecting 40 veterinary students with a single dose on each of days 0, 7 and 28. A second group of 20 students received the ordinary series of three 1.0 ml intramuscular vaccine doses by needle and syringe. All participants in both groups developed neutralizing antibodies to rabies above the suggested minimum of 0.5 international units per ml by day 49. The geometric mean titres were somewhat lower in the group receiving the 0.1 ml doses compared to the group given 1.0 ml doses; however, this was considered of no clinical significance since everyone achieved a titre above the suggested minimum. There was little difficulty in reconstituting the vaccine prepacked in the lumen of the syringe and the syringe was easy to manipulate.

Adult↗
PubMed1984

Antigenic characteristics of isolates associated with a new epizootic of raccoon rabies in the United States.

A panel of 23 monoclonal antibodies to the nucleocapsid protein of rabies virus was used to study the antigenic character of isolates of rabies virus from raccoons in the mid-Atlantic region of the United States. Comparison of the reaction pattern of these isolates with that of isolates of rabies virus collected from areas of major rabies outbreaks (skunk rabies in the midwestern United States, fox rabies in the northeastern United States, and raccoon rabies in the southeastern United States) suggests that this new epizootic originated with the transportation of rabid raccoons from the southeastern United States.

Animals↗
PubMed1984

Intradermal immunization with human diploid cell rabies vaccine: serological and clinical responses of immunized persons to intradermal booster vaccination.

Rabies antibody titers ranged from 0-9.3 IU/mL in 117 human volunteers one year after intradermal vaccination with one or two doses of human diploid cell rabies vaccine (HDCV). At that time, each volunteer received one 0.1-mL booster dose of HDCV intradermally. All 117 volunteers showed good anamnestic responses, with antibody titers rising to 0.5-54.3 IU/mL within seven days of booster injection. Vaccine safety was good; only minor reactions were experienced, all of which resolved spontaneously.

Drug Administration Schedule↗
PubMed1983

Rabies virus in the tonsils of a carrier dog.

A female dog, inoculated with a rabies isolate from the saliva of an apparently healthy Ethiopian dog, developed rabies but later recovered without supportive treatment. Rabies virus was isolated from the saliva collected 42, 169 and 305 days after recovery. Sixteen months after it recovered, the dog suddenly died after giving birth to two stillborn puppies. At necropsy, viral antigen could be detected in the tonsils and the brain tissue, but viable virus was isolated from the Palatine tonsils only.

Animals↗
PubMed1982

Intradermal immunization with human diploid cell rabies vaccine. Serological and clinical responses of persons with and without prior vaccination with duck embryo vaccine.

Intradermal administration of human diploid cell rabies vaccine (HDCV) was investigated in an attempt to reduce the current high cost of preexposure rabies prophylaxis. The study population consisted of 240 volunteers from a veterinary hospital, 165 of whom had prior vaccination with duck embryo rabies vaccine (DEV). Vaccine safety was good; only minor reactions were experienced, all of which resolved spontaneously. Serological responses to intradermal HDCV were excellent; 209 (99.5%) of the 210 persons who completed the study produced rabies antibody titers of 0.50 lU/mL or greater (range, 0.50 to 40.00 lU/mL). Two 0.1-mL doses of HDCV given intradermally 28 days apart provide a safe, effective, and economical method for human preexposure prophylaxis against rabies, irrespective of the previous DEV vaccination history of the recipient.

Animals↗
PubMed1982

Human diploid cell rabies vaccine. Effectiveness of immunization with small intradermal or subcutaneous doses.

To determine antibody responses to small doses of human diploid cell rabies vaccine (HDCV), we determined rabies antibody titers in 124 volunteers who had been vaccinated with one of five primary preexposure regimens. In a sixth group of 47 persons previously vaccinated with duck embryo rabies vaccine (DEV), we evaluated the booster responses after a 0.1-mL dose of intradermal (ID) HDCV. Persons in all five groups undergoing primary immunization received three doses of vaccine, one each on days 0, 7, and 28. The dose and route of vaccination for the five groups included 1 mL intramuscular (IM), 0.1 mL ID (two subgroups), 0.1 mL subcutaneous (SC), and 0.25 mL SC. Adequate titers developed in all persons, irrespective of the route or quantity of vaccine. The geometric mean titers (IU/mL) on day 49 in those receiving primary regimens were 12.87 (1.0 mL IM), 7.44 (0.1 mL ID by syringe), 3.05 (0.1 mL by jet injector), 3.17 (0.1 mL SC), and 6.47 (0.25 mL SC). Titers on day 90, while lower, were still acceptable. Adequate antibody titers developed in all persons previously vaccinated with DEV after a single 0.1-mL ID dose of HDCV; however, higher titers developed at day 7 in those who had shown an adequate response to DEV in the past. Results of this study suggest that HDCV may be used ID or SC for primary preexposure rabies prophylaxis and ID for booster immunization.

Adult↗