Evaluation of the immune responses in buffaloes vaccinated with a live-attenuated lumpy skin disease vaccine (Lumpi-ProVacInd).

Since 2019, Lumpy skin disease (LSD) has suddenly spread in many Asian countries, including India. LSD primarily occurs in cattle. However, recent LSD outbreaks in India have also revealed significant morbidity and production losses in buffaloes. This has raised concerns about the role of buffaloes in the epidemiology and transmission of LSD and necessitates the inclusion of buffaloes in the mass vaccination program for the prevention and control of the disease in the country. However, there is no significant data on the immune response in buffaloes following vaccination with the LSD vaccine. In this study, we evaluated antibody- and cell-mediated immune responses following vaccination with a newly developed live-attenuated LSD vaccine (Lumpi-ProVacInd). The detectable amount of anti-LSDV antibodies was observed at 1-2 months following vaccination, with a peak antibody titer at 3 months. Upon stimulation of the peripheral blood mononuclear cells (PBMCs) with the UV-inactivated LSDV antigen, there was a significant increase in CD8 + T cell counts in vaccinated animals as compared to the unvaccinated animals. Besides, vaccinated animals also showed a significant increase in IFN-γ levels upon antigenic stimulation of their PBMCs with LSDV antigen. In conclusion, the buffaloes also mount a potent antibody- and cell-mediated immune response following vaccination with Lumpi-ProVacInd.

Evaluation of different heterologous-homologous vaccine regimens against challenge with GI-23 lineage infectious bronchitis virus.

This study assesses different IBV vaccination regimens in broiler chickens using commercially available live attenuated GI-23 (Egyptian-VAR2) and GI-1 (H120) vaccines. Vaccines were administered at 1, 14 days of age, or both. The ciliostasis test, following wild-type VAR2 challenge at 28 days of age, indicated that classic H120+VAR2 at one day old followed by the VAR2 vaccine at 14 days of age provided the highest level of protection (89.58%). Similarly, administering VAR2 at 1 day of age and classic H120 at 14 days of age demonstrated substantial protection (85.42%). Conversely, administering only classic H120 and VAR2 at one day old resulted in the lowest protection level (54.17%). Tracheal virus shedding quantification and assessment of trachea and kidney degenerative changes were significantly lower in vaccinated groups compared to the unvaccinated-challenged group. In conclusion, a carefully planned vaccination regimen based on homologous vaccination offers the most effective clinical protection in broiler chickens.

Factors associated with the spatiotemporal distribution of dog rabies in Tunisia.

Despite continuous efforts of veterinary services to control rabies in dogs since 1982, rabies remains a cause of death in Tunisia, with more than five reported human cases in 2022. As little is known on the determinants of transmission of rabies in dogs, better understand which factors contribute to its spatial heterogeneity in Tunisia is critical for developing bespoke mitigation activities. In this context, we developed Bayesian Poisson mixed-effect spatio-temporal model upon all cases of rabid dogs reported in each delegation during the period from 2019 to 2021. The best fitting model highlighted the association between the risk of rabies and the mean average monthly temperature, the density of markets and the density of dogs in delegations. Interestingly, no relationship was found between intensity of vaccination in dogs and the risk of rabies. Our results provided insights into the spatio-temporal dynamics of dog rabies transmission and highlighted specific geographic locations where the risk of infection was high despite correction for associated explanatory variables. Such an improved understanding represent key information to design bespoke, cost-efficient, rabies prevention and control strategies to support veterinary services activities and policymaking.

Cytokine and acute-phase proteins response following vaccination against infectious bronchitis in broilers.

BACKGROUND: Infectious bronchitis (IB) is an important disease of poultry, and vaccination is the best method of preventing IB in the poultry industry worldwide. OBJECTIVES: This study was designed to evaluate cytokine and acute-phase protein (APP) responses and their correlations with antibody titres following vaccination regimes against IB in the broiler. MATERIALS AND METHODS: Broilers were vaccinated with H120 and 1/96 vaccine strains, and MIX (H120 + 1/96) vaccine strains on Days 0 and 14. Heterophils/lymphocyte (H/L) ratio, APPs including chicken serum amyloid A (SAA), chicken pentraxin 3 (chPTX3), chicken interleukin 1ß (IL-1ß), chicken interleukin 6 (IL-6) levels and antibody titres were measured. RESULTS: An increase in the H/L ratio, SAA, chPTX3, IL-1ß and IL-6 levels in vaccinated groups was observed 1 day after the first (highest rates) and second (lower levels) vaccination up to 3 days in three different patterns and then started to decrease. The results showed an immediate, short-lived response and moderate increases in all criteria. Changing patterns of APPs were different but in similar pattern after the first and second immunization in vaccinated groups. A positive correlation between all criteria values on Days 1 and 15 with antibody titres on Day 28 may indicate agonistic cross-regulation. CONCLUSION: Different types of IB vaccines could induce different patterns of APPs responses, which can be used to evaluate immune response outcomes in vaccine design, development and administration. The IL-6 with the highest increase can be a sensitive parameter and chPTX3 with the high increase could be an important criterion.

The first outbreak of Lumpy Skin Disease in Indonesia.

This study describes the first outbreak of Lumpy Skin Disease (LSD) in cattle in the Bengkalis region, Indonesia, and vaccination to control the epidemic. Data on the outbreak and vaccination was obtained from the local veterinary authority of the Bengkalis region, Indonesia. Climatological data was provided by the Meteorological, Climatological, and Geophysical Agency of Riau Province. Over the 5.5 months, the outbreak caused 10.4% (94/906) morbidity and 0.6% (6/906) mortality of cattle on infected farms. Temporally, three epidemic waves occurred during the outbreak period. Villages with cattle populations of > 150 animals (n = 36) were 5.3 times more likely to be infected with LSD compared to villages with smaller cattle populations (n = 107) (CI: 2.56-10.90, P < 0.01). The vaccination campaign covered 43.8% of cattle in villages within a 10 km radius of the cases. However, vaccination in villages with larger cattle populations (n = 29) was 0.63 less likely to cover 50% of the cattle populations compared to villages with smaller cattle populations (n = 41) (CI: 0.39-1.02, P = 0.05). By the time the first two and the major waves ceased, vaccination had covered only 0.0% (n = 6036), 27.8% (n = 6,036) and 9.7% (n = 5,697) of the cattle in the 10 km radius of the respective spatial clusters. The outbreak was statistically associated with rainfall and its interaction with temperature (F(2, 13) = 5.822, R2 = 0.47, P = 0.016). This study indicates that the LSD outbreak had low morbidity and mortality. Despite the low vaccination rate, the outbreak ceased, possibly due to plummeting of the abundance of insect vectors.

Defining correlates of protection for mammalian livestock vaccines against high-priority viral diseases.

Enhancing livestock biosecurity is critical to safeguard the livelihoods of farmers, global and local economies, and food security. Vaccination is fundamental to the control and prevention of exotic and endemic high-priority infectious livestock diseases. Successful implementation of vaccination in a biosecurity plan is underpinned by a strong understanding of correlates of protection-those elements of the immune response that can reliably predict the level of protection from viral challenge. While correlates of protection have been successfully characterized for many human viral vaccines, for many high-priority livestock viral diseases, including African swine fever and foot and mouth disease, they remain largely uncharacterized. Current literature provides insights into potential correlates of protection that should be assessed during vaccine development for these high-priority mammalian livestock viral diseases. Establishment of correlates of protection for biosecurity purposes enables immune surveillance, rationale for vaccine development, and successful implementation of livestock vaccines as part of a biosecurity strategy.

Livestock virus hits Europe with a vengeance.

Bluetongue spreads rapidly in sheep and cattle in six countries despite vaccination efforts.

Safety and DIVA Capability of Novel Live Attenuated Classical Swine Fever Marker Vaccine Candidates in Pregnant Sows.

Classical Swine Fever (CSF), a highly contagious viral disease affecting pigs and wild boar, results in significant economic losses in the swine industry. In endemic regions, prophylactic vaccination and stamping-out strategies are used to control CSF outbreaks. However, sporadic outbreaks and persistent infections continue to be reported. Although the conventional attenuated CSF vaccines protect pigs against the disease, they do not allow for the differentiation of infected from vaccinated animals (DIVA), limiting their use as an eradication tool. In this study, three targeted attenuation strategies were employed to generate vaccine candidates based on the current prevalent CSFV group 2 strains GD18 and QZ07: a single deletion of H79 in Erns (QZ07-sdErnsH-KARD), double deletion of H79 and C171 in Erns (GD18-ddErnsHC-KARD and QZ07-ddErnsHC-KARD), and deletion of H79 in Erns combined with a 5-168 amino acids deletion of Npro (GD18-ddNpro-ErnsH-KARD). Additionally, a negative serological marker with four substitutions in a highly conserved epitope in E2 recognized by the monoclonal antibody 6B8 was introduced in each candidate for DIVA purposes. The safety of these four resulting vaccine candidates was evaluated in pregnant sows. Two candidates, GD18-ddErnsHC-KARD and QZ07-sdErnsH-KARD were found to be safe for pregnant sows and unlikely to cause vertical transmission. Both candidates also demonstrated potential to be used as DIVA vaccines, as was shown using a proprietary blocking ELISA based on the 6B8 monoclonal antibody. These results, together with our previous work, constitute a proof-of-concept for the rational design of CSF antigenically marked modified live virus vaccine candidates.

Safety and Immunogenicity of Morbillivirus canis Vaccines for Domestic and Wild Animals: A Scoping Review.

Morbillivirus canis (canine distemper virus (CDV)) is recognized as a multihost pathogen responsible for a transmissible disease affecting both domestic and wild animals. A considerable portion of wildlife populations remain unvaccinated due to a lack of safety and immunogenicity data on existing vaccines for the prevention of CDV infection in these species. This review aimed to assess the current state of CDV vaccination research for both domestic and wild animals and to explore novel vaccine candidates through in vivo studies. It also sought to synthesize the scattered information from the extensive scientific literature on CDV vaccine research, identify key researchers in the field, and highlight areas where research on CDV vaccination is lacking. A scoping review was conducted across four databases following the PRISMA-ScR protocol, with information analyzed using absolute and relative frequencies and 95% confidence intervals (CIs) for study number proportions. Among the 2321 articles retrieved, 68 met the inclusion criteria and focused on CDV vaccines in various animal species, such as dogs, ferrets, minks, and mice. Most of the scientific community involved in this research was in the USA, Canada, France, and Denmark. Various vaccine types, including MLV CDV, recombinant virus, DNA plasmids, inactivated CDV, and MLV measles virus (MeV), were identified, along with diverse immunization routes and schedules employed in experimental and commercial vaccines. Safety and efficacy data were summarized. Notably, 37 studies reported postimmunization CDV challenge, primarily in dogs, revealing the survival rates of vaccinated animals. In summary, CDV vaccines generally demonstrate an acceptable safety profile in dogs and show promise as a means of controlling CDV. However, significant gaps in vaccine research persist, particularly concerning wildlife reservoirs, indicating the need for further investigation.

Foals of mares vaccinated for Hendra virus have a suboptimal response to HeV vaccination.

Hendra virus (HeV) is lethal to horses and a zoonotic threat to humans in Australia, causing severe neurological and/or respiratory disease with high mortality. An equine vaccine has been available since 2012. Foals acquire antibodies from their dams by ingesting colostrum after parturition, therefore it is assumed that foals of mares vaccinated against HeV will have passive HeV antibodies circulating during the first several months of life until they are actively vaccinated. However, no studies have yet examined passive or active immunity against HeV in foals. Here, we investigated anti-HeV antibody levels in vaccinated mares and their foals. Testing for HeV neutralising antibodies is cumbersome due to the requirement for Biosafety level 4 (BSL-4) containment to conduct virus neutralisation tests (VNT). For this study, a subset of samples was tested for HeV G-specific antibodies by both an authentic VNT with infectious HeV and a microsphere-based immunoassay (MIA), revealing a strong correlation. An indicative neutralising level was then applied to the results of a larger sample set tested using the MIA. Mares had high levels of HeV-specific neutralising antibodies at the time of parturition. Foals acquired high levels of maternal antibodies which then waned to below predictive protective levels in most foals by 6 months old when vaccination commenced. Foals showed a suboptimal response to vaccination, suggesting maternal antibodies may interfere with active vaccination. The correlation analysis between the authentic HeV VNT and HeV MIA will enable further high throughput serological studies to inform optimal vaccination protocols for both broodmares and foals.

Assessing farmers' willingness to pay for FMD vaccines and factors influencing payment: a contingent valuation study in central Oromia, Ethiopia.

BACKGROUND: Foot and mouth disease is a contagious, transboundary, and economically devastating viral disease of cloven-hoofed animals. The disease can cause many consequences, including decreased productivity, limited market access, and elimination of flocks or herds. This study aimed to assess farmers' willingness to pay (WTP) for foot and mouth disease (FMD) vaccines and identify factors influencing their WTP. A cross-sectional questionnaire survey was conducted on 396 randomly selected livestock-owning farmers from three districts in the central Oromia region (Ambo, Dendi, and Holeta districts. The study utilized the contingent valuation method, specifically employing dichotomous choice bids with double bounds, to evaluate the willingness to pay (WTP) for the FMD vaccine. Mean WTP was assessed using interval regression, and influential factors were identified. RESULTS: The study revealed that the farmer's mean willingness to pay for a hypothetical foot and mouth disease vaccine was 37.5 Ethiopian Birr (ETB) [95% confidence interval [CI]: 34.5 40.58] in all data, while it was 23.84 (95% CI: 21.47-26.28) in the mixed farming system and 64.87 Ethiopian Birr (95% CI: 58.68 71.15) in the market-oriented farming system. We identified main livelihood, management system, sales income, breed, keeping animals for profit, and foot and mouth disease impact perception score as significant variables (p ≤ 0.05) determining the farmers' WTP for the FMD vaccine. CONCLUSION: Farmers demonstrated a high computed willingness to pay, which can be considered an advantage in the foot and mouth disease vaccination program in central Oromia. Therefore, it is necessary to ensure sufficient vaccine supply services to meet the high demand revealed.

The mRNA vaccine platform for veterinary species.

Vaccination has proven to be an effective means of controlling pathogens in animals. Since the introduction of veterinary vaccines in the 19th century, several generations of vaccines have been introduced. These vaccines have had a positive impact on global animal health and production. Despite, the success of veterinary vaccines, there are still some pathogens for which there are no effective vaccines available, such as African swine fever. Further, animal health is under the constant threat of emerging and re-emerging pathogens, some of which are zoonotic and can pose a threat to human health. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has highlighted the need for new vaccine platforms that are safe and efficacious, but also importantly, are adaptable and can be modified rapidly to match the circulating pathogens. mRNA vaccines have been shown to be an effective vaccine platform against various viral and bacterial pathogens. This review will cover some of the recent advances in the field of mRNA vaccines for veterinary species. Moreover, various mRNA vaccines and their delivery methods, as well as their reported efficacy, will be discussed. Current limitations and future prospects of this vaccine platform in veterinary medicine will also be discussed.

Insights into canine rabies vaccination Disparities in Sierra Leone: A cross-sectional household study.

Annually, Sierra Leone records an estimated 301 human fatalities due to rabies. Canine vaccination is crucial for rabies prevention and control efforts. However, considerable variability exists in vaccination rates. Reasons for this variation remain unclear. We conducted a cross-sectional study across 2,558 dog-owning households (HHs) to provide insights into factors influencing canine vaccination for targeted prevention and control towards elimination by 2030. First, we described dog ownership practices, then built a probabilistic model to understand factors associated with dog vaccination, and finally used a spatial scan statistic to identify spatial clusters where vaccination rates were low. Our results indicated that only 14% (358/2,558) of participating HHs had fully vaccinated their dogs against rabies. The probability of dog vaccination increased when comparing civil servants to private workers/artisans, with an Odds Ratio(OR) of 1.14 (95% credible interval (Crl) of 0.82-1.56), residing in locations with a veterinary establishment vs. none (OR = 6.43, 95% Crl (4.97-8.35), providing care to dogs vs. allowing dogs to roam freely (OR = 2.38, 95% Crl(1.80-3.17) and owning a single dog vs multiple dogs (OR = 1.20, 95 Crl (0.92-1.56). Conversely, there was a decrease in the estimated probability of vaccination when comparing dog owners located in rural vs. urban areas (OR = 0.58, CrI 95% (0.43-0.78). Latent understanding, a measure of overall understanding of rabies virus, which we estimated using participant education levels and responses to questions about rabies epidemiology, was also an important predictor of vaccination probability (OR = 1.44, 95% Crl (1.04-2.07). The spatial analysis identified high-risk clusters for low vaccination in the cities of Moyamba, with a radius of 40 km, a relative risk (RR) of 1.10, and Bo, with a radius of 19.9 km with RR of 1.11. These data do not support Sierra Leone reaching the 2030 goal of human rabies elimination caused by dogs. Our study highlights a critical need for public outreach and education, improved vaccination rates, increased accessibility to veterinary services, and targeted interventions in Bo and Moyamba to support rabies prevention and control efforts.

Fish Iridoviridae: infection, vaccination and immune response.

Each year, due to climate change, an increasing number of new pathogens are being discovered and studied, leading to an increase in the number of known diseases affecting various fish species in different regions of the world. Viruses from the family Iridoviridae, which consist of the genera Megalocytivirus, Lymphocystivirus, and Ranavirus, cause epizootic outbreaks in farmed and wild, marine, and freshwater fish species (including ornamental fish). Diseases caused by fish viruses of the family Iridoviridae have a significant economic impact, especially in the aquaculture sector. Consequently, vaccines have been developed in recent decades, and their administration methods have improved. To date, various types of vaccines are available to control and prevent Iridoviridae infections in fish populations. Notably, two vaccines, specifically targeting Red Sea bream iridoviral disease and iridoviruses (formalin-killed vaccine and AQUAVAC® IridoV, respectively), are commercially available. In addition to exploring these themes, this review examines the immune responses in fish following viral infections or vaccination procedures. In general, the evasion mechanisms observed in iridovirus infections are characterised by a systemic absence of inflammatory responses and a reduction in the expression of genes associated with the adaptive immune response. Finally, this review also explores prophylactic procedure trends in fish vaccination strategies, focusing on future advances in the field.

Would you bet on the vet? Influences on dairy farmers' vaccination choices, with a spotlight on the Veterinarian impact.

Ensuring effective vaccination is crucial for epidemic control, particularly in voluntary vaccination scenarios. Though highly important for planning voluntary vaccination programs, we lack insights into the effectiveness of veterinarian communication and the impact of disease-specific traits on farmer vaccination intentions. To fill this void, our study compared five diseases affecting Israeli dairy cattle (Botulism, Bovine Ephemeral Fever (BEF), Brucellosis, Lumpy Skin Disease (LSD), and Rabies). Using questionnaires grounded in the theory of planned behavior, we surveyed 340 Israeli dairy farmers to understand their vaccination intentions for each disease.Simultaneously, veterinarians overseeing these farms provided insights into their opinions and perceived influence on vaccination decisions. Results revealed varying levels of farmer vaccination intention, with Botulism showing the highest and BEF the lowest. Social pressure significantly influenced farmers' vaccination intentions, with distinct patterns across diseases. Veterinarian opinions had the highest influence only for LSD, while other factors played crucial roles in different diseases. Intriguingly, there was no correlation between veterinarians' recommendations and farmers' perceptions of these recommendations. In conclusion, the optimization of voluntary vaccination programs necessitates tailoring interventions to the unique characteristics of each disease. Additionally, improving communication between veterinarians and farmers is essential, with an emphasis on effective risk communication training.

Vaccinating parent flocks against colibacillosis reduces broiler mortality - A retrospective observational study from 2016 to 2019 in Finland.

Colibacillosis is one of the most important infectious diseases in modern poultry production. The complex nature of colibacillosis has made it challenging to produce an effective vaccine. As a control measure for colibacillosis outbreak in Finland, a vaccination program with a commercial colibacillosis vaccine and later also an autogenous vaccine was started for parent flocks in 2017. In this retrospective observational study from years 2016-2019, we evaluated first week and total mortality of broiler flocks (n= 6969) originating from parents with different colibacillosis vaccination status. Broiler flocks were divided into three groups according to vaccination status of their parent flocks. First group were flocks from parents with no colibacillosis vaccines; second group was flocks from parents vaccinated with commercial vaccine only; and third group was flocks from parents with both commercial and autogenous vaccine. Bayesian modelling was used to predict posterior distributions of first week mortality and total mortality of the broiler flocks. Results of the modelling revealed that broiler flocks from unvaccinated parents had the highest mortality rates (mean first week mortality 1.40 % and mean total mortality 4.33 %, respectively) whereas flocks from parents with a combination of commercial and autogenous vaccinations had the lowest mortality rates (mean first week mortality 0,91 % and mean total mortality 3,14 %). The mortalities from broilers flocks from parents with only commercial vaccine fell in between these groups. Also, standard deviations of mortality rates were lower in broilers from parents with commercial or both vaccines. This demonstrates that in addition to lowering the mean mortality rates, the vaccinations made high mortality broiler flocks less common. Best performance was obtained when autogenous vaccine was combined to the commercial vaccine. The autogenous vaccine consists of the same type of Escherichia coli strain that was causing most colibacillosis cases during the study period in Finland. This study adds to the evidence of benefits of colibacillosis vaccines during outbreaks. It also demonstrates the importance of the knowledge of the types of APEC strains causing outbreaks to produce effective autogenous vaccines.

Comparative safety and efficacy of autogenous vaccine administrated by different routes against furunculosis caused by Aeromonas salmonicida sub. salmonicida in large Rainbow trout (Oncorhynchus mykiss).

The development and growth of fish farming are hindered by viral and bacterial infectious diseases, which necessitate effective disease control measures. Furunculosis, primarily caused by Aeromonas salmonicida, stands out as a significant bacterial disease affecting salmonid fish farms, particularly rainbow trout. Vaccination has emerged as a crucial tool in combating this disease. The objective of this experiment was to assess and compare the efficacy and duration of different vaccine protocols against furunculosis in large trout under controlled rearing conditions, utilizing single and booster administrations via intraperitoneal, oral, and immersion routes. Among the various vaccination protocols tested, only those involving intraperitoneal injection, administered at least once, proved truly effective in preventing the expression of clinical signs of furunculosis and reducing mortality rates. A single intraperitoneal administration provided protection for up to 2352°-days, equivalent to approximately 5 months in water at 16 °C. However, intraperitoneal vaccination may lead to reduced growth in the fish due to resultant intraperitoneal adhesions. Additionally, protocols incorporating booster doses via intraperitoneal injection demonstrated efficacy regardless of the administration route of the primary vaccination. Nevertheless, the use of booster vaccinations via the intraperitoneal route did not confer any significant advantage over a single intraperitoneal injection in terms of efficacy.

Influence of bovine pestivirus heterogeneity on serological responses to 10 different commercial vaccine formulation.

Bovine Pestivirus typically involves one or more organ systems, with clinical manifestations ranging from mild to severe fatal systemic illness that lead to significant reproductive, productive, and economic losses. Vaccines face the challenge of addressing the significant variability of pestiviruses, which affects the interaction between viral antigens and the immune system's ability to provide protection. This study aimed to evaluate the serological responses against bovine viral diarrhea virus 1 (Pestivirus A) and Pestivirus B induced by 10 commercial vaccines, including one recombinant (vaccine E), two modified live (MLV multivalent, vaccine I, and MLV monovalent, vaccine J), and seven killed vaccines (KLV, vaccines A to H). Additionally, we evaluated the cross-reactivity between Pestivirus A and B from vaccines and HoBi-like pestivirus (Pestivirus H). In Phase 1, guinea pigs were used to screen for non-MLVs. They were divided into nine groups (n=6 each) and received two doses (⅕ of bovine dose) of eight different non-MLV on Days 0 and 21. Serum samples were collected on Days 0 and 30 for serological analyse. In Phase 2, Holstein × Gir heifers (n= 45) were divided into five groups, comprising 6-9 animals. They were vaccinated either once with MLVs or twice with the top non-MLVs screened in Phase 1. Serum samples were harvested on d0 (vaccination day) and d60 (60 days after the first dose) for MLV and non-MLV. Specific antibody titers were assessed virus neutralization (VN) and transformed in log2 for statistical analysis using PROC-MIXED. Significant effects were observed for vaccine groups, time points, and their interactions concerning neutralizing antibodies against Pestivirus A and B in both Guinea pigs and heifers. The Phase 1 study revealed serological responses against Pestivirus A exclusively in non-MLV D (85.33±13.49) and E (72.00±19.26). In the bovine study, the KLD vaccine D (72.00±15.10), recombinant vaccine E (90.66±25.85), and MLV I (170.66±28.22) resulted in an average of neutralizing antibodies against Pestivirus A that exceeded the protective threshold (≥ 60). However,individual analysis of heifers showed a higher frequency of animals presenting titers of Pestivirus A Ab surpassing 32 following vaccination with MLV I and J. None of the vaccine formulations in either study elicited a protective immune response against Pestivirus B or demonstrated cross-reactivity against Pestivirus H.

Study on the interference of vaccine antibodies with the serological diagnosis of leptospirosis in cattle.

A simple IgG-specific ELISA for Leptospira spp. was compared with the microscopic agglutination test (MAT) to detect IgG antibody responses to a commercial vaccine in cattle. We used an enzyme-linked immunosorbent assay (ELISA) with sonicated Leptospira interrogans serovar copenhageni M 20. After initial vaccination, specific antibodies against Leptospira spp. were detected in 90 % of the animals by IgG-ELISA and 60 % by MAT, while after booster, antibodies were detected in 100 % and 80 % of the animals by IgG-ELISA and MAT, respectively. Both serological MAT and ELISA tests revealed interferences of vaccine antibodies. Disease diagnosis with ELISA and MAT methods should be made two and a half months and four months, respectively, after vaccination to avoid interference of vaccine antibodies. On the other hand, our results suggest that IgG-ELISA may be a useful method to assess the development of IgG antibodies induced by Leptospira vaccine.