Rabies Antibody Research Articles

Immunization of Cattle Against Rabies Using Inactivated Cell Culture Vaccines

Twenty-one heads of cattle were vaccinated with Madibovin, 31 with Rabdomun and 127 with Rabisin on 4 different farms. Rabies neutralizing antibody titre (> or = 0.5 IU/ml) was detected in 80% of 163 animals tested about 1 month and in 42% of 133 animals tested about 1 year after primary vaccination. On 3 of the farms 86 animals received booster vaccination about 1 year after primary vaccination. All these animals had antibody titre (> or = 0.5 IU/ml) about 1 month after booster and antibody levels were higher than after the primary vaccination. Rabies antibody titres (> or = 0.5 IU/ml) were detected in 96% of 50 animals tested 1 year after the booster. No significant differences (p > 0.05) in antibody levels were detected between animals vaccinated with Madibovin or Rabisin (farm C) respectively with Rabisin or Rabdomun (farm D) at any collection time. Responses to rabies vaccines varied considerably between the farms. After primary vaccination of the animals on 2 farms with the same batch of Rabisin, the antibody levels clearly differed (p < 0.0001) between the farms. Our results indicate that booster is always necessary after primary vaccination to ensure that all animals are protected.

Calibration of a Replacement Preparation for the International Standard for Rabies Immunoglobulin

Abstract. A proposed replacement preparation for the International Standard for Rabies Immunoglobulin was calibrated by means of two assay methods, a neutralization test in mice (MNT) and a neutralization test in cell culture (RFFIT). The calibration was made as an international collaborative assay comprising nine laboratories in eight countries. The results obtained in this study confirm earlier observations about occasional unexplainable differences between relative potencies obtained by the two methods. They also confirm the apparent reliability of the RFFIT. Based on the results obtained the proposed replacement preparation has been established as the second International Standard for Rabies Immunoglobulin with a defined unitage of 30 International Units of Rabies Antibodies in each ampoule.

Survey of fox trappers in northern Alaska for rabies antibody

The purpose of this research was to determine whether trappers in northern Alaska acquired immunity to rabies virus from non-bite exposures while trapping and skinning arctic foxes (Alopex lagopus). In coastal Alaska recurring epizootics presumably provide trappers ample opportunity for contact with rabid animals. Serum neutralization analyses of blood samples collected from 26 individuals were conducted. All but three had negative rabies neutralizing antibody levels (< 0.05 I.U./ml). Two of these had previously received rabies vaccine but one individual who had trapped for about 47 years with an estimated harvest of over 3000 foxes and who had never received pre- or post-exposure rabies vaccination had a rabies serum neutralizing antibody concentration of 2.30 I.U./ml. This represents the first report of an unvaccinated person acquiring rabies virus antibody with a titre above the 0.5 I.U./ml level considered acceptable by the World Health Organization.

Tollwutantikörper‐Bildung bei Frettchen nach der Impfung mit vier verschiedenen Tollwut‐Impfstoffen

The Development of Rabies Antibodies in Ferrets after Injection of Four Different Types of Rabies Vaccines. Experiments aimed at proving the suitability of ferrets in the routine testing of rabies vaccines for human and animal use were carried out. A total of 40 ferrets received four vaccines, two for use in humans and two for use in animals. For the determination of rabies antibodies, blood was taken on days 28 and 56, respectively, after inoculation of the vaccines. All animals developed antibodies of more than [0.5 IE/ml] serum as determined by RFFIT. The antibody titre following injection of the vaccines for animals (A1 and A2) was 4.1 IE/ml on day 28 and 5.86 IE/ml on day 56. The antibody titre following injection of the vaccines for humans was 6.64 IE/ml on day 28 and 8.87 IE/ml on day 56. The suitability of ferrets for the potency assay of rabies vaccines is discussed.

Rabies in African wild dogs (Lycaon pictus) in the Serengeti region, Tanzania.

Rabies was confirmed as the cause of death of one African wild dog (Lycaon pictus) in the Serengeti region, Tanzania. One adult African wild dog in the same pack showed central nervous signs consistent with rabies infection. Inactivated rabies vaccine was administered intramuscularly to African wild dogs in two packs, by dart or by hand following anesthesia. These individuals comprised all known adults in the Serengeti National Park. In a limited study of seroprevalence of rabies antibody carried out at the time of vaccination, 3 of 12 African wild dogs sampled in the Serengeti had rabies serum neutralizing antibody titers before vaccination. Paired serum samples from two individuals sampled after vaccination showed increased antibody titers.

Practical significance of rabies antibodies in cats and dogs.

Doubt has sometimes been cast upon the protective effect of rabies antibodies in serum. Animals and humans suffering from fatal rabies often produce high antibody titres, while rabies cases are also observed in vaccinated animals. Cellular immunity is also largely involved in protection. Nevertheless, a large number of laboratory experiments and field observations clearly demonstrate that cats and dogs which develop antibodies after vaccination and before challenge have a very high probability of surviving any challenge, no matter how strong the dose and which virus strain was used. Rabies antibody titration can, therefore, afford a strong additional guarantee to the vaccination certificates accompanying domestic carnivores during transportation between countries. Quarantine rules should also be adapted to the epidemiological features in the exporting country, e.g. statistics of vaccination failure in cats and dogs and host-virus adaptation of the rabies strains circulating in these countries.

Detection of rabies antibody by ELISA and RFFIT in unvaccinated dogs and in the endangered Simien jackal (Canis simensis) of Ethiopia.

Varying levels of rabies antibody have been detected both by Enzyme Linked Immunosorbent Assay (ELISA) and Rapid Fluorescent Focus Inhibition Test (RFFIT) in the sera collected from wild and domestic canids in the Bale Mountains National Park (BMNP) of Southern Ethiopia. Rabies antibody was detected in 80% (8 out of 10) of domestic dog samples, 13.3% (2 out of 15) of Simien jackal samples and in one common jackal. Rabies virus was isolated from one dog in an area where contact with the Simien jackal could possibly occur. All samples examined from wild rodents as possible reservoir hosts for rabies were found negative. The presence of large proportion of susceptible Simien jackals in the population should be a cause of great concern in saving this endangered species from the ravages of rabies.

Using the UV ParaLens ® adapter on a standard laboratory microscope for fluorescent rabies antibody detection

Using the UV ParaLens ® adapter on a standard laboratory microscope for fluorescent rabies antibody detection

Immune response to rabies vaccine in Thai dogs: A preliminary report

Serum neutralizing antibody to rabies virus was determined in previously unvaccinated Thai pet dogs after receiving one subcutaneous dose of inactivated tissue culture rabies vaccine (Rabdomun, Coopers Animal Health Company, Germany, 4.55 IU ml −1 potency). Geometric mean titres on days 14, 30, 60, 180 and 360 were 2.14, 2.30, 0.45, 0.14 and 0.05 IU ml −1, respectively, by the rapid immunofluorescent focus inhibition test. Titres of neutralizing antibody to rabies virus did not correlate with the age of the dog at the time of vaccination or with the presence or absence of anaemia or blood parasites. Six out of 50 (12%), 11 out of 43 (25.6%) and 13 out of 31 (42%) dogs had not detectable rabies antibody in serum 60, 180 and 360 days, respectively, after vaccination. Three of these antibody-negative dogs were given another dose of vaccine. Antibody reappeared on day 14 but rapidly declined within 60 days. These data suggest that one dose of tissue culture vaccine in dogs by the subcutaneous route of injection is not adequte to maintain rabies neutralizing antibody in serum for 1 year.

One-year study of the 2-1-1 intramuscular postexposure rabies vaccine regimen in 100 severely exposed Thai patients using rabies immune globulin and Vero cell rabies vaccine

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.

The quantitation of rabies-specific antibodies III. A comparative evaluation of modified counter immunoelectrophoresis, haemagglutination inhibition and serum neutralization titres of human sera

The rabies-specific antibodies of 73 serum samples from vaccinated humans were determined by the modified counter immunoelectrophoresis (MCIE), and the haemagglutination inhibition test (HAI) by using the conventional serum neutralization test (SN) as a yard-stick. Both MCIE and HAI were found to be sensitive and specific for the estimation of rabies antibodies. In general, the unitages obtained by the MCIE and SN showed statistically insignificant differences ( P> 0·05) and the correlation coefficient between the two methods was 0·697 ( P < 0·05). Although the unitage of the sera detected by HAI tests was lower by a factor of 0·155 from the unitage of SN tests, there was statistically insignificant differences between the two techniques ( P > 0·05) with a correlation coefficient of 0·556 ( P < 0·05).

The quantitation of rabies-specific antibodies I. Modified counter immunoelectrophoresis. A rapid and sensitive method

Modified counter immunoelectrophoresis was standardized with respect to dilution of tissue culture antigen and indicator serum, the incubation time for neutralization and the effect of an electric current. The technique was found to be sensitive enough to detect a minimum level of antibodies (0·5 IU/ml) by using a 16 mA current per slide for 2 h, indicator serum of 15 IU/ml and the use of an antigen at a concentration of 1:35. Above all, the incubation period did not affect the neutralization of the virus. The test was also applied to the detection of rabies-specific antibody levels in 73 human sera. The test was found to be simple, quick and economical for titration of rabies antibodies.

Evaluación de la calidad de los reactivos que se utilizan en la tecnica de contrainmunoelectroforesis para la determinación de anticuerpos antirrábicos

This study demonstrated that the antigens and indicator sera produced by the Butantan Institute may be employed with success in the counterimmunoelectrophoresis technique for the titration of rabies antibodies in sera from immunized individuals. No statistically significant differences were demonstrated between the results obtained in the standardization tests carried out at the Butantan Institute and the reference control tests performed at the Pan American Zoonoses Center. It is proposed that the Butantan Institute be in charge of the production and distribution of these reagents at the national level.

Rabies antibody profile among pregnant females administered therapeutic postexposure vaccine during pregnancy, their neonates and infants

Rabies antibody profile among pregnant females administered therapeutic postexposure vaccine during pregnancy, their neonates and infants

INTRAMUSCULAR VACCINATION OF SKUNKS AND RACCOONS AGAINST RABIES

Live-captured striped skunks (Mephitis mephitis) and raccoons (Procyon lotor) were immunized with inactivated rabies vaccine by intramuscular injection and released at the point of capture during a rabies control program in Metropolitan Toronto (Ontario, Canada). Serum samples collected prior to and following vaccination revealed that 100% of the skunks and 98% of the raccoons seroconverted. Rabies antibody was still detectable 314 to 757 days postvaccination. Five of six skunks vaccinated in the laboratory survived challenge with rabies virus 90 days postvaccination. To our knowledge, this is the first documentation of the successful seroconversion of skunks and raccoons vaccinated against rabies in the field.

Eosinophilic Encephalomyelitis in a Raccoon Experimentally Infected with a Dog Isolate of Rabies Virus

For the past decade, the mid-Atlantic region of the United States has been experiencing an epizootic of rabies in its wild raccoon (Procyon lotor) population. In 1987, there were 965 reported cases of rabid raccoons in this geographical location.* To counteract this epidemic, a genetically engineered vaccinia-rabies glycoprotein (V-RG) oral rabies vaccine has been developed and has been evaluated experimentally in raccoons. 10 It is now awaiting final government approval for field testing. An adult female raccoon used in a control group of animals for the experimental evaluation of the V-RG recombinant virus vaccine was presented to the Laboratory of Large Animal Pathology at the University of Pennsylvania for necropsy. The raccoon had been inoculated intramuscularly with 0.3 ml of rabies virus strain MD5951 (10 5.5 MICLD50), which had been isolated from a dog. 12 On day 12 postinoculation (PI) the raccoon had shown vague neurologic signs and was euthanized on the day of presentation (day 13 PI). Prior to euthanasia, blood samples were obtained for hematology and for the serum neutralization test for rabies antibody. 10

Seroepidemiological Survey of Rabies Virus Antibodies in Non Vaccinated Dogs in Nsukka Environs, Nigeria

Serum samples from 254 non vaccinated and apparently healthy dogs of local breeds in Nsukka environs, Nigeria were examined for the presence of antibodies to rabies virus by haemagglutination-inhibition technique. The prevalence rates of rabies antibodies in, less than 3 months, 3-6 months, and over 6 months old dogs were 17.5%, 7.3% and 22.8% respectively, and overall 16.1% in the dog population. This was the first documented report of rabies antibodies in non vaccinated dogs in Eastern Nigeria. The results were discussed with respect to the epidemiology of prototype rabies and rabies-related viruses. It was suggested that the antibodies were most probably due to the non virulent prototype rabies or rabies-related virus strains. 83.9% of susceptible dogs in the population suggested a mandatory regular a vaccination of all dogs in interest of public health and control of the disease. The study highlighted the need for more studies on epidemiology of rabies and rabies-related viruses in Nigeria.

Prevalence of rabies specific antibodies in the Mexican free-tailed bat (Tadarida brasiliensis mexicana) at Lava Cave, New Mexico.

Adult female and juvenile Mexican free-tailed bats (Tadarida brasiliensis mexicana) were collected bimonthly at Lava Cave, New Mexico from May through September. The purpose of this study was to examine the prevalence of active rabies infection as well as to determine individual immune status in these hosts. All bats were bled and examined for rabies antibody (total antibody versus IgM) utilizing a modified serum neutralization test. The brains were removed and examined by the fluorescent rabies antibody (FRA) test. No significant difference was observed in the number of adults with rabies neutralizing antibody (total) over the study period. Significant differences in rabies neutralizing antibody (total) were observed among the juveniles sampled during July and August. The number of adults with IgM specific antibody was low (15 of 750, 2%) and did not fluctuate significantly. However, the number of juveniles with IgM antibody did show increased levels in August and September. The number of adults positive by the FRA was low (4 of 750, less than 1%) and did not appear to fluctuate significantly over the study period. The number of juveniles positive by the FRA was three and one-half times higher than observed for the adults (14 of 600, 2%). These results indicate that the Mexican free-tailed bat appears to be exposed to rabies virus shortly after birth as evident by its immune status. The low prevalence (4 of 750, less than 1%) of active infection as determined by the FRA and mouse inoculation and the high prevalence (514 of 750, 69%) of IgG antibody in the adult females indicate that the Mexican free-tailed bat recovers from rabies virus infection.

Enzyme-linked immunosorbent assay (ELISA) using staphylococcal protein A for the measurement of rabies antibody in various species.

An ELISA was developed using staphylococcal protein A linked with horseradish peroxidase for detecting IgG antibody of rabies virus in human and carnivore sera (80 human, 270 fox, 40 cat, 35 marten, 5 badger and 4 polecat sera were tested in the present work). In comparison with the serum neutralization (SN) test in cell culture, close overall agreement was obtained particularly in human and cat sera (97.5%). Two post-vaccination human sera were found positive with ELISA values of 2.16 and 2.65 IU/0.2 ml, but with SN titers less than 1:10. All prevaccination human sera were found negative by both tests. Regression analysis on 30 post-vaccination human sera revealed better correlation between ELISA and SN test at a serum dilution of 1:100 than at lower serum dilutions of 1:80 or 1:20. The correlation coefficient (r) was 0.73 (p less than or equal to 0.0001).

Serological survey for rabies antibodies in raptors from California.

Fifty-three newly captive birds of prey were tested serologically for neutralizing antibodies against rabies virus, using a fluorescent focus inhibition test. No significant antibody titers were detected with this sensitive and specific technique in any of these birds. This study supports the contention that free-ranging birds of prey are of limited importance in the epidemiology of rabies.