G M Baer

National Institute of Allergy and Infectious Diseases, Maryland, United States

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Publications (59)500.86 Total impact

  • Jean S. Smith, Pamela A. Yager, George M. Baer
    Annals of the New York Academy of Sciences 12/2006; 350(1):568 - 569. · 4.38 Impact Factor
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    ABSTRACT: Protocols for evaluating oral rabies vaccine baits for domestic dogs were field tested in central Mexico, after which dog-food manufacturers and suppliers to the pet-food industry were advised as to potential ingredients for use in prototype dog baits. Bait-preference trials in which confined dogs were used were then undertaken, followed by field tests of free-ranging farmer-owned dogs in three towns in the Nile River Delta region of Egypt. Both confined and free-ranging dogs showed strong preferences for certain baits or bait coatings (poultry, beef tallow, cheese, egg and a proprietary product). Fish-meal polymer baits, widely used for wildlife species, were less preferred. In Egypt, a commercial dog-food-meal bait coated with beef tallow and dry cheese, was consumed at a rate approaching that of a chicken-head bait. The percentage baits that were actually eaten after they had been offered to dogs, ranged from 71-96% for household dogs tested in Mexico, 65-91% for confined dogs (beagles and mixed breeds) tested in the United States, and 32-88% for farmer-owned dogs tested in Egypt.
    The Onderstepoort journal of veterinary research 07/1997; 64(2):115-24. · 0.55 Impact Factor
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    ABSTRACT: From 1 July 1987 to 31 December 1988, 30% of 247 rabid dogs in Hermosillo, Mexico had a positive history of rabies vaccination. Serosurveys suggested that inactivated suckling mouse brain vaccine (INACT-SMBV) and inactivated tissue culture vaccine (INACT-TC) used before and during the epizootic were poor immunogens. Prospective studies showed that only about one-third of dogs vaccinated with INACT-SMBV were seropositive 5 weeks after vaccination. Lack of vaccine potency was the most likely cause of poor immunogenicity. Rabies vaccines should be evaluated periodically by measuring antibody responses in animals. In some circumstances, minimum seroconversion rates and antibody titres in vaccinated animals may be better measures of immunogenicity than relative potency.
    Vaccine 12/1994; 12(14):1259-64. · 3.49 Impact Factor
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    ABSTRACT: Dogs were vaccinated intradermally with vaccinia virus recombinants expressing the rabies virus glycoprotein (G protein) or nucleoprotein (N protein) or a combination of both proteins. The dogs vaccinated with either the G or G plus N proteins developed virus-neutralizing antibody titers, whereas those vaccinated with only the N protein did not. All dogs were then challenged with a lethal dose of a street rabies virus, which killed all control dogs. Dogs vaccinated with the G or G plus N proteins were protected. Five (71%) of seven dogs vaccinated with the N protein sickened, with incubation periods 3 to 7 days shorter than that of the control dogs; however, three (60%) of the five rabid dogs recovered without supportive treatment. Thus, five (71%) of seven vaccinated with the rabies N protein were protected against a street rabies challenge. Our data indicate that rabies virus N protein may be involved in reducing the incubation period in dogs primed with rabies virus N protein and then challenged with a street rabies virus and, of more importance, in subsequent sickness and recovery.
    Journal of Virology 06/1992; 66(5):2601-4. · 5.08 Impact Factor
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    ABSTRACT: Twenty nine skunks (Mephitis mephitis) were vaccinated orally with raccoon poxvirus (RCN) recombinants: 10 with a recombinant expressing the rabies virus glycoprotein (RCNRG), 10 with RCNRG mixed with a recombinant expressing the rabies virus nucleoprotein (RCNRN) and nine with RCN alone. Rabies virus neutralizing antibodies were detected in six of the 20 skunks; five skunks (three given RCNRG, two given a mixture of recombinants) survived a rabies challenge that was lethal for nine skunks vaccinated with RCN alone.
    Journal of wildlife diseases 11/1991; 27(4):681-4. · 1.27 Impact Factor
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    ABSTRACT: Intraperitoneal vaccination of mice with rabies vaccine results in both dosage-dependent rabies virus neutralizing antibody titres and protection from lethal intracerebral (i.c.) challenge with fixed strain CVS rabies virus. Pre-exposure adoptive intravenous transfer of naive or immune cells did not significantly protect naive Balb/c mice from lethal i.c. CVS challenge, but immune serum and anti-rabies glycoprotein monoclonal antibodies (individually and in combination) did confer significant protection when administered before or up to 24 h after lethal i.c. rabies virus challenge.
    Vaccine 10/1991; 9(9):638-42. · 3.49 Impact Factor
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    ABSTRACT: The 2-1-1 rabies postexposure treatment schedule is an abbreviated regimen in which a tissue culture rabies vaccine is administered intramuscularly at two sites on day 0, and at one site on days 7 and 21. Compared to the standard five-dose intramuscular regimen, the 2-1-1 schedule reduces the number of clinic visits from five to three and the amount of vaccine used by 20%. One hundred Thai patients, who were severely exposed to rabies, were treated with rabies immune globulin and the 2-1-1 regimen using purified Vero cell rabies vaccine. They were followed for 1 year. Rabies antibody titres were measured in 10% of this group. All patients survived and adverse reactions were mild. A satisfactory antibody response (a titre > 0.5 IU ml−1) occurred in all ten patients studied at day 14, but persisted for 90 days in 80% and for 360 days in only 50%. The authors therefore do not recommend use of the 2-1-1 schedule in severely exposed patients who also need to receive rabies immune globulin.
    Vaccine 09/1991; · 3.49 Impact Factor
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    ABSTRACT: Captive raccoons were offered a variety of vaccine containers and bait components in a series of three-choice tests. Paraffin wax ampules were the most readily accepted vaccine container. Preferred bait components included corn and shellfish oils, deep fried corn meal batter, and egg, apple and buttermilk flavorings. These results, together with factors including ease of bait formulation, cost, and suitability for field use, were used to develop an experimental delivery system for an oral rabies vaccine. The developed system was composed of a polyurethane sleeve (1.5 x 5.5 cm) dipped in a commercial food batter mix together with corn meal, milk and egg. The sleeve was deep fried in corn oil and a 2.0 ml ampule containing a recombinant rabies vaccine was then inserted into the sleeve bait. These baits were presented to 10 captive raccoons. Nine of the 10 animals developed high levels of rabies virus neutralizing antibodies. Field tests are needed to determine if the delivery system developed also is effective for wild raccoons.
    Journal of wildlife diseases 02/1991; 27(1):21-33. · 1.27 Impact Factor
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    ABSTRACT: The Thai Red Cross intradermal postexposure rabies treatment schedule was prospectively assessed in 100 Thai patients severely bitten by proven rabid animals. It consists of 0.1 ml of purified Vero cell rabies vaccine containing more than 2.5 IU of rabies antigen per 0.5 ml of reconstituted vaccine given intradermally at two sites on days 0, 3, and 7, followed by one 0.1 ml injection on days 30 and 90. The commercial vaccine used had an antigen content of 3.17 IU per 0.5 ml ampoule. Purified equine or human rabies immuno-globulin was also given on day 0 to patients with severe exposures. As much of the immunoglobulin as possible was infiltrated around the wounds. All patients were followed for 1 year post exposure. There were no deaths; the efficacy of the regimen was 100%. Antibody titre determination in a randomly selected subgroup showed seroconversion in all 10 patients.
    The Lancet 05/1990; 335(8694):896-8. · 39.21 Impact Factor
  • The Lancet 04/1990; 335(8690):664-5. · 39.21 Impact Factor
  • D B Fishbein, G M Baer
    Annals of internal medicine 01/1989; 109(12):935-7. · 13.98 Impact Factor
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    ABSTRACT: Two infectious raccoon poxvirus (RCN) recombinants for expressing rabies virus surface spike glycoprotein (G) were produced by homologous recombination between raccoon poxvirus DNA and chimeric plasmids previously used for production of vaccinia virus recombinants. Expression of G protein was controlled by vaccinia virus promoter P7.5 (early/late class) or by P11 (late class). Immunoprecipitation of infected cell extracts indicated that both of the RCN recombinants directed faithful expression of G protein. Raccoons that were fed polyurethane baits loaded with either recombinant quickly developed high levels of rabies virus neutralizing antibodies and were protected when challenged with lethal raccoon rabies street virus.
    Virology 08/1988; 165(1):313-6. · 3.37 Impact Factor
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    ABSTRACT: 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.
    American Journal of Veterinary Research 03/1988; 49(2):169-71. · 1.35 Impact Factor
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    ABSTRACT: 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.
    Journal of Clinical Microbiology 01/1988; 25(12):2440-2. · 4.07 Impact Factor
  • G M Baer, D B Fishbein
    New England Journal of Medicine 06/1987; 316(20):1270-2. · 54.42 Impact Factor
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    ABSTRACT: 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.
    The American journal of tropical medicine and hygiene 02/1987; 36(1):160-5. · 2.53 Impact Factor
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    ABSTRACT: 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.
    The Southeast Asian journal of tropical medicine and public health 01/1987; 17(4):543-9. · 0.61 Impact Factor
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    ABSTRACT: 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.
    Journal of Clinical Microbiology 11/1986; 24(4):573-80. · 4.07 Impact Factor
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    ABSTRACT: 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.
    MMWR. CDC surveillance summaries: Morbidity and mortality weekly report. CDC surveillance summaries / Centers for Disease Control 02/1985; 34(1):11SS-27SS.
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    ABSTRACT: 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.
    Vaccine 10/1984; 2(3):185-8. · 3.49 Impact Factor

Publication Stats

966 Citations
500.86 Total Impact Points

Institutions

  • 1994
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States
  • 1982–1994
    • Centers for Disease Control and Prevention
      • • National Center for Emerging and Zoonotic Infectious Diseases
      • • Division of Viral Diseases
      Atlanta, Michigan, United States
  • 1991
    • U.S. Department of Health and Human Services
      Washington, Washington, D.C., United States
    • Animal and Plant Health Inspection Service
      Buzzards Bay, Massachusetts, United States