Antibody seroprevalences against rabies in dogs vaccinated under field conditions in Bolivia

Bolivia currently has one of the highest numbers of cases for human and canine rabies and is thus clue to the elimination process. The objective of the present study was to assess antibody seroprevalences against rabies in dogs vaccinated under field conditions and other factors that might influence the success of the on-going rabies control programmes in an endemic area of the disease, Santa Cruz de la Sierra, Bolivia. All 240 study animals, selected using area-stratified random sampling, were investigated in April 2007. Test prevalences were adjusted for the imperfect test characteristics using the Rogan–Gladen estimator (deterministic and stochastic functions) and Bayesian inference. Ninety-four of the tested 240 vaccinated dogs were classified as test-positive for rabies-specific antibodies. With regard to adjusted overall antibody seroprevalence, Bayesian true prevalence estimates (41%, 95% CI: 37–46%) were lower than both of the Rogan–Gladen estimates. The effect of various epidemiological factors on post-vaccination response was also assessed.     

The serological response to a thermostable Vero cell-adapted rinderpest vaccine under field conditions in Niger

A lyophilized thermostable Vero cell-adapted ringerpest vaccine, stabilized with lactalbumin hydrolysate and sucrose, was tested for safety, serological response and suitability for use with an abbreviated cold chain under field conditions in Niger. A total of 480 cattle, 90 goats and 55 sheep of unknown serological status were vaccinated on government ranches and observed for at least 22 days. No untoward effects of the vaccine were detected. The serological response to the vaccine stored at environmental temperatures for 30 to 34 days was determined in 144 previously unvaccinated yearling calves. Seroconversion was demonstrated in 98% of the yearling calves using seroneutralization. The un-refrigerated vaccine retained a titer of 3.69 log10 TCID50 per dose through day 34.     

Antibody response of cattle to rinderpest vaccine

Antibody production was studied in cattle infected with rinderpest vaccine virus. Vaccinated cattle produced both IgM and IgG serum antibodies. The IgG antibodies were mainly those of IgG2 subclass. No IgA antibody response was detected in vaccinated animals.     

商品鸭流感疫苗免疫抗体的监测

高致病力流感(HPAD)可侵害各种日龄的商品鸭，造成严重的死亡和产蛋下降，给养鸭业造成巨大的威胁。无母源抗体的雏鸭从3日龄开始，直至出栏均可感染发病。感染鸭群表现明显的精神沉郁、采食下降或不食。感染鸭有明显的神经症状，出现头颈扭曲、抽搐，严重者瘫软在地，强行驱赶后，神经症状表现更为明显。出现临床症状后不久，鸭群开始出现死亡，之后2～3天，死亡率急速上升，死亡率可达到30％以上，甚至100％死亡。产蛋种鸭感染后首先表现采食量下降，然后出现产蛋急速下降，一般下降30％～60％，严重者可高达60％～90％，甚至停产。无并发感染时，一般不出现死亡率明显升高的现象，但比正常淘汰率略高。     

Immunity against paralytic rabies in cattle following vaccination with era vaccine under ranch conditions in Bolivia

Summary Six of 15 cattle vaccinated 5 years previously with ERA-MLV rabies vaccine had S/N titres 1: 5 or greater. A further eight animals whose titres were less than 1: 5 responded anamnestically to revaccination indication that 14 of the group of 15 (97 per cent) had a serviceable immunity 5 years after primary vaccination.

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Résumé Six des quinze boeufs vaccinés cinq ans auparavant avec la souche ERA/MLV ont montré des titres de séroneutralisation égaux ou supérieurs à cinq. Huit autres dont les titres de séroneutralisation étaient inférieurs au 1: 5 ont, présenté un phénomène de rappel à la revaccination; ces résultats montrent que quatorze des quinze animaux d'expérience (97 pour cent) avient une immunité décelable cinq ans après la primo-vaccination.

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Sumario Seis, de quince bovinos vacunados cinco, a?os atras con la vacuna contra rabia ERA-MLV, tenían títulos S/N de 1: 5 ó, superiores. Ocho animales más con títulos menores de 1: 5 respondieron anamnésicamente a la revacunación indicando de esta manera que 14 del grupo de 15 animales (97 por ciento) conservaban una inmunidad útil cinco a?os después de la primera vacunación.

     

Evaluation of Mycoplasma hyopneumoniae inactivated vaccine in pigs under field conditions

An inactivated vaccine prepared from broth culture supernatant of Mycoplasma hyopneumoniae with an aluminum adjuvant was evaluated in three herds (herd A: specific pathogen-free herd, herd B: high health status herd with no clinical signs of respiratory infection, herd C: low health status herd with serious epidemiological and economical problems). A total of 212 pigs from the three herds were divided into two groups. One group was injected twice with the vaccine at 4-week intervals and the other was a control group. No adverse reactions were noted following the vaccinations either systematically or locally in any of the vaccinated pigs from any of the herds. In herd A, the vaccination provided antibody response within 4 weeks after the second vaccination and antibody responses continued for more than 12 weeks. In herds B and C, the number of pigs with lung lesions, mean percentage of lung lesions, and the numbers of M. hyopneumoniae recovered from pigs at slaughter in the vaccinated group were significantly (P < 0.05) reduced compared to the control group. Furthermore, vaccination resulted in improved average daily weight gain (ADG), improved feed conversion ratio (FCR), and improved days to market weight in herd C, whereas no difference in growth performance was shown in herd B. It is suggested that the inactivated vaccine prepared from broth culture supernatant of M. hyopneumoniae is effective in reducing clinical signs and lung lesions. Also, vaccination resulted in improved growth performance in herds where clinical signs and economic losses were significant.     

Immunity against paralytic rabies in cattle following vaccination with era rabies vaccine under ranch conditions in Bolivia

Summary Vaccination of cattle against paralytic rabies with modified live virus ERA vaccine under extensive ranching conditions in Bolivia is described. It was shown that for practical purposes satisfactory protection was being conferred. As the vaccinated herds were composed, of animals of varying immune status, further investigation is required to evaluate the duration of protection conferred by ERA vaccine under field conditions.

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Sumario Se describe la vacunación de ganado bovino en contra de la rabia paresiante con vacuna de virus vivo inactivado ERA, bajo condiciones de ganaderia extensiva en Bolivia. Se demostro que, con fines prácticos, una protección satisfactoria fue conferida a estos hatos. No fue posible lograr el fin perseguido, que era comparar esta vacuna con una de virus inactivado elaborada con tejido de cerebros, por la decisión de indole administrativa tomada por los due?os. Como los hatos estaban compuestos por animales de diverso estado de inmunidad cuando los vacunaron, será necesario continuar investigando como evaluar la duraci n de la protección conferida por la vacunz ERA bajo condiciones de campo.

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Résumé On décrit la vaccination de bovins contre la rage paralytique avec du vaccin modifié vivant ERA dans des conditions d'élevage extensif. Il a été démontré que les troupeaux ont été protégés d'une fa?on satisfaisante à des fins pratiques. L'objet original de l'étude, la comparaison de ce vaccin avec celui provenant de tissu cerebral inactivé, n'a pas été possible à cause d'une décision de gestion par les propriétaires. Les troupeaux étant composés d'animaux en état immunitaire variable, des recherches supplémentaires sont nécessaires pour évaluer la durée de la protection conférée par le vaccin ERA dans des conditions pratiques.

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Commercial product of Connaught Medical Research Laboratories (CMRL), modified live virus of porcine tissue culture origin

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The paper was prepared following an assignment as Veterinary Adviser of the Food and Agriculture Organization of the United Nations, financed by Funds in Trust donated by OXFAM to the Freedom from Hunger Campaign     

Efficacy of a live bovine herpesvirus type 1 marker vaccine under field conditions in three countries

The performance of a live marker vaccine for bovine herpesvirus type 1 (bhv-1) was studied in the field in three European Union countries with different farming conditions. The progress in the eradication of the virus was followed in a large herd in Germany and one in Italy, and a major serological survey involving 147 farms was conducted in Hungary. Commercial batches of the same vaccine were used in all three studies. The herds were vaccinated according to agreed protocols and the animals' bhv-1 antibody status was determined at local institutes by using commercial glycoprotein B (gB)- and glycoprotein E (gE)-elisas. In all three studies, the seroprevalence of bhv-1 gE decreased progressively. Given the starting conditions and the long duration of the studies, reactivation events and virus circulation would have been more likely to have occurred if the herds had not been vaccinated.     

Efficacy of attenuated Anaplasma marginale vaccine under laboratory and field conditions in Colombia

Four-month-old Holstein-Friesian calves were inoculated with 3 different doses (1, 2, and 3 ml) of attenuated Anaplasma marginale vaccine. Vaccinated calves showed mild anaplasma parasitemia, slight decrease in packed cell volume, low serologic conversion, and no clinical illness. An artificial challenge exposure of vaccinated and unvaccinated calves with virulent Colombian A marginale showed that the vaccine provided protection against clinical signs of the disease, including parasitemia and anemia. The volume of the vaccinal dose did not alter the degree of protection provided. A 2nd group of 8- to 9-month-old Holstein-Friesian calves was then inoculated with 3 ml of anaplasma vaccine and premunized with both Babesia bigemina and Babesia argentina while being housed in an area free of these diseases. Calves were moved to an enzootic region heavily infested with various arthropods, including ticks, for natural field challenge exposure. Control calves, which were not given anaplasma vaccine, suffered clinical illness manifested by severe anemia and an average weight loss of 50.6 kg due to anaplasma field challenge exposure. In contrast, vaccinated calves did not show anemia and their weight loss was 3.9 kg.     

Antibody response to an inactivated vaccine for rhinotracheitis, caliciviral disease, and panleukopenia in nondomestic felids

The efficacy of an inactivated vaccine for the prevention of feline viral rhinotracheitis (FVR), feline caliciviral disease (FCVD), and feline panleukopenia (FPL) was tested in 27 nondomestic adult felids from 7 species. The vaccine was given IM at the standard domestic cat dose in 19 animals and double this dose in 8 others. The animals were vaccinated either 1, 2, or 3 times. Serum-neutralization (SN) antibodies to FVR (mean SN titer, 23) developed in all 15 animals that were previously seronegative, and SN antibodies to FCVD (mean SN titer, 11) developed in 19 of 21 animals that were previously seronegative. There was no significant increase of SN antibody titers by doubling the vaccine dose or by administering a 3rd vaccination. The optimal response could be obtained by using the domestic cat vaccination protocol of a single dose given twice, 4 weeks apart. The critical evaluation of the SN antibody titer for FPL was complicated by preexisting titers to FPL from previous vaccinations, but in 23 animals the titers became higher, whereas they remained unchanged in only 4 animals. The persistence of the SN titers was evaluated 7 to 9 months later and found to be satisfactory for FVR (mean SN titer, 18) FCVD (mean SN titers, 43) and FPL (mean SN titer, 517). Enhanced persistence of titer could not be demonstrated by doubling the dose or administering a 3rd vaccination.     

Stability of vaccinia-vectored recombinant oral rabies vaccine under field conditions: a 3-year study

Rabies is an incurable zoonotic disease caused by rabies virus, a member of the rhabdovirus family. It is transmitted through the bite of an infected animal. Control methods, including oral rabies vaccination (ORV) programs, have led to a reduction in the spread and prevalence of the disease in wildlife. This study evaluated the stability of RABORAL, a recombinant vaccinia virus vaccine that is used in oral rabies vaccination programs. The vaccine was studied in various field microenvironments in order to describe its viability and facilitate effective baiting strategies. Field microenvironments influenced the stability of this vaccine in this study. This study emphasizes the importance of understanding how vaccines perform under varying field conditions in order to plan effective baiting strategies.     

Antibody response to and maternal immunity from an experimental psittacine beak and feather disease vaccine.

Adult umbrella cockatoos, Moluccan cockatoos, African grey parrots, and a yellow-headed Amazon parrot were inoculated IM or SC with beta-propiolactone-treated psittacine beak and feather disease (PBFD) virus. Thirty- to 45-day-old African grey parrot, umbrella cockatoo, and sulphur-crested cockatoo chicks also were vaccinated with the same inoculum. The hemagglutination inhibition (HI) and agar-gel diffusion tests were used to assay for post-vaccination development of anti-PBFD virus antibodies. All adult vaccinates seroconverted and had increases in HI and precipitating antibodies. The vaccinated chicks had increased concentrations of HI antibodies, but precipitating antibodies could not be detected. To demonstrate that chicks from vaccinated hens are protected from PBFD virus challenge, 3 African grey parrot chicks and 2 umbrella cockatoo chicks from vaccinated hens and 1 African grey parrot chick and 1 umbrella cockatoo chick from nonvaccinated hens were exposed to purified PBFD virus. Chicks from the vaccinated hens remained clinically normal during the 50-day test period. Chicks from the nonvaccinated hens developed clinical and histologic lesions of PBFD. Infected tissues from these birds were confirmed to contain viral antigen, using immunohistochemical staining techniques. The PBFD virus was recovered from the affected birds. These findings indicate that adult and 30- to 45-day-old psittacine birds will seroconvert following vaccination with beta-propiolactone-treated PBFD virus. Also, hens inoculated with beta-propiolactone-treated PBFD virus produce chicks that are, at least temporarily, resistant to virus challenge.