Third-generation smallpox vaccines induce low-level cross-protecting neutralizing antibodies against Monkeypox virus in laboratory workers.

Due to the discontinuation of routine smallpox vaccination after its eradication in 1980, a large part of the human population remains naïve against smallpox and other members of the orthopoxvirus genus. As a part of biosafety personnel protection programs, laboratory workers receive prophylactic vaccinations against diverse infectious agents, including smallpox. Here, we studied the levels of cross-protecting neutralizing antibodies as well as total IgG induced by either first- or third-generation smallpox vaccines against Monkeypox virus, using a clinical isolate from the 2022 outbreak. Serum neutralization tests indicated better overall neutralization capacity after vaccination with first-generation smallpox vaccines, compared to an attenuated third-generation vaccine. Results obtained from total IgG ELISA, however, did not show higher induction of orthopoxvirus-specific IgGs in first-generation vaccine recipients. Taken together, our results indicate a lower level of cross-protecting neutralizing antibodies against Monkeypox virus in recipients of third-generation smallpox vaccine compared to first-generation vaccine recipients, although total IgG levels were comparable.

Canine Distemper Virus in Tigers (Panthera tigris) and Leopards (P. pardus) in Nepal.

From wild dogs (Lycaon pictus) in the Serengeti to tigers (Panthera tigris altaica) in the Russian Far East, canine distemper virus (CDV) has been repeatedly identified as a threat to wild carnivores. Between 2020 and 2022, six Indian leopards (P. pardus fusca) presented to Nepali authorities with fatal neurological disease, consistent with CDV. Here, we report the findings of a serosurvey of wild felids from Nepal. A total of 48 serum samples were tested, comprising 28 Bengal tigers (P. t. tigris) and 20 Indian leopards. Neutralizing antibodies were identified in three tigers and six leopards, equating to seroprevalences of 11% (CI: 2.8-29.3%, n = 28) and 30% (CI: 12.8-54.3%, n = 20), respectively. More than one-third of seropositive animals were symptomatic, and three died within a week of being sampled. The predation of domestic dogs (Canis lupus familiaris) has been posited as a potential route of infection. A comparison of existing diet studies revealed that while leopards in Nepal frequently predate on dogs, tigers do not, potentially supporting this hypothesis. However, further work, including molecular analyses, would be needed to confirm this.

Development of ELISA for the detection of antibodies against VP2 protein of bluetongue virus serotype-1.

Serotype-specific diagnosis of bluetongue virus (BTV) is necessary for sero-surveillance and taking effective control measures. The VP2 is the major serotype determining protein and BTV-1 is the most predominant serotype in India. In the present study, an indirect ELISA (i-ELISA) was optimized for the detection of serotype-specific antibody against BTV-1 serotype. The VP2 protein of BTV-1 was expressed in a prokaryotic expression system and used to optimize i-ELISA to detect VP2 antibodies of BTV-1 in serum samples of both small and large ruminants. Serum samples (n = 363) classified as positive and negative for antibodies to BTV-1 by serum neutralization test (SNT) and also positive and negative for BTV antibodies by c-ELSIA kit (VMRD, USA) were used to determine the cut-off value, diagnostic sensitivity (DSn), and diagnostic specificity (D-Sp) using receiver operating characteristic (ROC) analysis. The percent positivity (PP) value >30.10% was accepted as the cut-off for i-ELISA at which DSn of 99.52% and D-Sp of 99.35% was observed with a 95% confidence interval. Further, there was no cross-reactivity with other available BTV serotypes in the country. The study indicated serotype-specific i-ELISA is sensitive, specific and suitable alternative to tedious SNT method for determining serotype. The assay will also help in the serotype-specific epidemiological studies and implementation of future control strategies including vaccination and selection of suitable serotype as a vaccine candidate.

Seroprevalence and Associated Risk Factors of Lumpy Skin Disease of Cattle in Selected Districts of Afar Region, Ethiopia.

Background: Lumpy skin disease (LSD) is one of Ethiopia's most economically significant transboundary livestock illnesses. The disease has a significant economic impact on pastoral household livestock owners, who rely significantly on their cattle as a source of income. Methods: A cross-sectional study was undertaken in selected districts of Afar region from November 2018 to May 2019 primarily intended to estimate the prevalence of lumpy skin disease serologically in local Afar cattle as well as identify potential associated factors. A multistage sampling method was employed to select study districts, peasant association, herd size and study units. A total of 384 sera were processed using serum neutralization test (SNT) method to detect antibodies against lumpy skin disease virus. Relevant data were refined and further analyzed using stata version 14. Results: In the study districts, the overall animal level seroprevalence was found to be 7.6% (N = 29/384; 95% confidence interval: 4.90-10.20) and the overall herd level prevalence was found to be 20.8% (n = 15/72; 95% confidence interval: 11.42-30.18). Only district was shown to be statistically significant (P = 0.004) in terms of LSD occurrence among the relevant factors studied. Cattle in Chifra district were 20.18 times more likely to contract LSD infection than cattle in Dubti district, when Asayita district was used as the reference group. Conclusion: The present study finding confirmed the presence of the disease in the study districts of afar region and coordinated intervention set to be in place.

Preparation and the assessed efficacy of oral baits for the vaccination of free-roaming dogs against rabies.

Background and Aim: Rabies is considered a highly fatal zoonotic disease and many deaths in humans have been associated with dog bites. This study was designed to prepare an oral anti-rabies vaccine in the form of baits to eliminate the disease in free-roaming dogs and subsequently protect humans from dog bites. Materials and Methods: The Evelyn Rokintniki Abelseth (ERA) rabies virus strain was propagated in baby hamster kidney cell cultures and adjusted to the recommended dose for application. Four forms of oral baits were employed with the rabies vaccine, which was evaluated for safety, acceptability, and potency in different dog groups. Enzyme-Linked Immunosorbent Assay (ELISA) and the serum neutralization test (SNT) were used to determine the protective rabies antibody titer in the sera of vaccinated dogs. Results: According to the results, a dose of 3 mL of the ERA strain, containing a viral titer of 107.6 TCID50/mL, induced a mean antibody titer of 25.6 by SNT, and the PI% was 75.7 by Block ELISA, providing a protective level of the rabies antibody in 100% of vaccinated dogs. All used baits were found to be safe, inducing no abnormal general post-vaccination signs (the signs are limited to mild fever, mild loss of appetite, and mild-to-moderate loss of energy for 24-36 h after vaccination). Conclusion: It was found that most of the accepted and highly potent bait types consisted of a mixture of wheat flour, vegetable oil, sodium alginate, corn starch, meat meal, cellulose gum, and water. This dog meal was covered with bran and edible wax to seal the bait cavity after inserting the vaccine sachet. This bait was able to induce a protective level of rabies antibodies in 100% of vaccinated dogs after receiving one bait/dog. Hence, such a bait could be recommended for use in the protection of free-roaming dogs and the elimination of the disease.

A simple method for purification of epsilon toxin of Clostridium perfringens type D for serum neutralization assay.

Enterotoxaemia, a disease that affects domestic ruminants, is caused by the epsilon toxin of Clostridium perfringens type D and B. Control and prophylaxis are based on systemic vaccination of small ruminant herds with epsilon toxoid. Purified epsilon toxin is an essential material for vaccine evaluation. It is also necessary for diagnosis of enterotoxaemia disease in the field by in vitro tests including ELISA. The aim of this study was to set up a method for preparation of functional purified epsilon toxin of C. perfringens type D to be used in serum neutralization test. In this study, epsilon toxin was prepared from C. perfringens type D culture precipitated with ammonium sulfate, dialyzed against phosphate buffered saline (PBS) buffer and then, purified using chromatography system. Then, the purified epsilon toxin was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Toxin function was confirmed by cell culture and minimum lethal dose (MLD) assays. Also rabbits were immunized by vaccine in two turns with a 28-day interval. Then, blood samples were collected, and serum neutralization (SN) test was carried out. Results showed that the purified toxin was suitable for SN assay. Our purification method was simple, fast and cost-effective for preparation of epsilon toxin.

Hendra virus: Epidemiology dynamics in relation to climate change, diagnostic tests and control measures.

Hendra virus (HeV) continues to pose a serious public health concern as spillover events occur sporadically. Terminally ill horses can exhibit a range of clinical signs including frothy nasal discharge, ataxia or forebrain signs. Early signs, if detected, can include depression, inappetence, colic or mild respiratory signs. All unvaccinated ill horses in areas where flying foxes exist, may potentially be infected with HeV, posing a significant risk to the veterinary community. Equivac® HeV vaccine has been fully registered in Australia since 2015 (and under an Australian Pesticides and Veterinary Medicines Authority special permit since 2012) for immunization of horses against HeV and is the most effective and direct solution to prevent disease transmission to horses and protect humans. No HeV vaccinated horse has tested positive for HeV infection. There is no registered vaccine to prevent, or therapeutics to treat, HeV infection in humans. Previous equine HeV outbreaks tended to cluster in winter overlapping with the foaling season (August to December), when veterinarians and horse owners have frequent close contact with horses and their bodily fluids, increasing the chance of zoonotic disease transmission. The most southerly case was detected in 2019 in the Upper Hunter region in New South Wales, which is Australia's Thoroughbred horse breeding capital. Future spillover events are predicted to move further south and inland in Queensland and New South Wales, aligning with the moving distribution of the main reservoir hosts. Here we (1) review HeV epidemiology and climate change predicted infection dynamics, (2) present a biosecurity protocol for veterinary clinics and hospitals to adopt, and (3) describe diagnostic tests currently available and those under development. Major knowledge and research gaps have been identified, including evaluation of vaccine efficacy in foals to assess current vaccination protocol recommendations.

Type-specific seroprevalence of bluetongue in India during 2018 and 2019.

BACKGROUND AND AIM: Bluetongue (BT) is a major disease of sheep and goats and is endemic to India. It is known to cause significant economic losses to the sheep industry. The current study aimed to determine the type-specific seroprevalence of BT in sheep population of India during 2018-2019. MATERIALS AND METHODS: Blood samples (n=405) were collected from 6 months to 1 year old sheep from six districts (Nalgonda, Karimnagar, Khammam, Mahabubnagar, Warangal, and Ranga Reddy) of Telangana state, India. Group- and type-specific seroprevalence (against BT virus [BTV] serotypes BTV-1, 2, 4, 5, 9, 10, 12, 16, 21, 23, and 24) was studied by competitive enzyme-linked immunosorbent assay and serum neutralization test, respectively. RESULTS: Results showed an overall seroprevalence of 14.81% (n=60) with the highest seroprevalence of 50% in Khammam district. Seroprevalence of BTV-1, 2, 4, 5, 9, 10, 12, 16, 21, 23, and 24 was noted as 16.66%, 11.66%, 31.66%, 11.66%, 05%, 6.66%, 16.66%, 8.33%, 13.33%, 6.66%, and 16.66%, respectively. The majority of the sera neutralized more than 1 serotype, indicating superinfection or circulation of multiple serotypes in the sampled flocks. This mixed seroprevalence was observed in 43.33% of the sera with number of BTV serotype-specific antibodies ranging from two to eight in individual animals. CONCLUSION: Regular monitoring of circulating serotypes, especially in young herds, elucidates pattern of dominating serotypes in a particular area during a season. This knowledge can be applied to design appropriate vaccination strategies by including particular serotypes of virus as part of a multivalent vaccine for a particular period, in a particular area.

Development of a High-Throughput Serum Neutralization Test Using Recombinant Pestiviruses Possessing a Small Reporter Tag.

A serum neutralization test (SNT) is an essential method for the serological diagnosis of pestivirus infections, including classical swine fever, because of the cross reactivity of antibodies against pestiviruses and the non-quantitative properties of antibodies in an enzyme-linked immunosorbent assay. In conventional SNTs, an immunoperoxidase assay or observation of cytopathic effect after incubation for 3 to 7 days is needed to determine the SNT titer, which requires labor-intensive or time-consuming procedures. Therefore, a new SNT, based on the luciferase system and using classical swine fever virus, bovine viral diarrhea virus, and border disease virus possessing the 11-amino-acid subunit derived from NanoLuc luciferase was developed and evaluated; this approach enabled the rapid and easy determination of the SNT titer using a luminometer. In the new method, SNT titers can be determined tentatively at 2 days post-infection (dpi) and are comparable to those obtained by conventional SNTs at 3 or 4 dpi. In conclusion, the luciferase-based SNT can replace conventional SNTs as a high-throughput antibody test for pestivirus infections.

Comparative immune responses of pups following modified live virus vaccinations against canine parvovirus.

BACKGROUND AND AIM: Canine parvovirus (CPV) is the most important viral cause of enteritis and mortality in pups. Evaluation and monitoring of pre- and post-vaccine immune responses may help to determine the efficacy of the current vaccination schedule being followed in pups in India. This study aimed to evaluate and monitor the pre- and post-vaccine immune responses of CPV vaccinated pups using hemagglutination inhibition (HI) assay. The neutralizing antibody titer levels were also detected using serum neutralization test (SNT). MATERIALS AND METHODS: The pups were categorized into two groups, the double booster and the single booster groups. In this study, serum samples were subjected to HI and SNT for measuring the CPV antibody titer at frequent intervals for up to 6 months from 27 healthy pups following primary and booster CPV vaccinations. RESULTS: The antibody titers in double booster pups reached their peaks at the 21st day after the second booster vaccination with a geometric mean (GM) of 3.57. The antibody titers in single booster pups reached their peaks at the 21st day after the first booster vaccination with a lower GM of 3.18. CONCLUSION: The double booster pups maintained a higher immune response throughout the period of the study compared to single booster pups though the difference in titers was not statistically significant. SNT results indicated that the raised antibody titer was also able to yield virus-neutralizing antibodies. No interfering maternally derived antibodies were found in the pups at the age of primary vaccination (45th day) in our study. Therefore, the second booster vaccination may be useful in maintaining the protective titer for a prolonged period.

Development of an Indirect Enzyme-linked Immunosorbent Assay to Detect Antibodies against Serotype A2013 of Foot and Mouth Disease Virus in Cattle.

Foot and mouth disease (FMD) is a contagious animal disease that causes irreparable damage to the economy of countries, including Iran in which this disease is a native one. Among the ways to combat FMD are vaccination and slaughter. Due to the specific situation of Iran, it is not possible to kill infected animals. Therefore, vaccination is the most important way to fight this disease. Serum neutralization test (SNT) and enzyme-linked immunosorbent assay (ELISA) are two main methods to evaluate the safety and calculate antibody titer. In this study, an indirect ELISA test was developed based on the coating of a complete viral particle (140s) which made it possible to determine antibody. In addition, serotype and viral type were determined without the need for time-consuming and complex molecular tasks, including gene expression. Moreover, in case of a new epidemic, a new epidemic condition can be detected using a serum antibody method. However, the coating of the complete viral particle leads to virus purification as well as the conjugated anti-immunoglobulin antibody testing of the same animal. In this study, the SNT was used as a gold standard test to determine the serum antibody level and compare its results with indirect ELISA method to determine the sensitivity and specificity of the indirect ELISA. To measure the anti-virus antibody rate of FMD (type A2013) through receiver operating characteristic analysis with 100% sensitivity and the specificity of 90%, the routine formulas were utilized using 100 % and 82%sensitivity and specificity, respectively. In this study, the cutoff value for the optical density was obtained at 0.3 and there was a significant difference between the vaccinated animals and the unvaccinated ones in terms of antibody level against the A2013 type. This indicates the correctness of the test and the accurate and proportional antibody detection against the understudy viral types of FMD.

Tick-borne encephalitis virus in cows and unpasteurized cow milk from Norway.

Tick-borne encephalitis virus (TBEV) is recognized as the most important zoonotic tick-transmitted virus in Europe. TBEV is mainly transmitted to humans through bites from TBEV-infected ticks (Ixodes ricinus and Ixodes persulcatus). However, alimentary infection after consumption of unpasteurized milk and cheese from domestic ruminants has been reported. There is little information about TBEV in ruminants in Norway. The objectives of this study were to analyse unpasteurized cow milk for TBEV RNA and to study the presence of IgG antibodies to TBEV in the same animals. A total of 112 milk and blood samples were collected from cows from five different farms spread from southern to northern Norway. The milk samples were analysed by an in-house reverse transcription (RT) real-time polymerase chain reaction and confirmed by pyrosequencing. Serum samples were screened by a commercial enzyme-linked immunosorbent assay and verified by a TBEV-specific serum neutralization test. We found TBEV RNA in unpasteurized milk collected from farms in the municipalities of Mandal, Skedsmo and Brønnøy in 5.4% of the tested animals. Specific antibodies to TBEV were only detected in Arendal, where 88.2% of the tested animals were positive. Further studies on milk containing TBEV RNA should be performed to conclude if TBEV found in unpasteurized milk in Norway is infectious, which could be of great importance in a One Health perspective.

Evaluation of purified recombinant spike fragments for assessment of the presence of serum neutralizing antibodies against a variant strain of porcine epidemic diarrhea virus.

Since 2010, variant strains of porcine epidemic diarrhea virus (PEDV) have caused disasters in the pork industry. The spike (S) protein, as the major immunity-eliciting antigen, has previously been used for serological testing and has been found to correlate significantly with the results of the serum neutralization (SN) test. However, further evaluation of this method is needed as new epidemic strains of PEDV emerge. Hence, the main objective of this study was to assess sow sera and determine the correlation between enzyme-linked immunosorbent assay (ELISA) results (involving a newly isolated GDS01 virus-based ELISA and ELISAs based on seven recombinant fragments comprising overlapping S1 and partial S2 sequences) and SN titers. Furthermore, we determined the reliability of the ELISAs based on receiver operating characteristics (ROC) curve analyses. For the most promising ELISA, i.e., the SP4 ELISA, the correlation coefficient (r) and the area under curve (AUC) were determined to be 0.6113 and 0.8538, respectively. In addition, we analyzed the homology of the SP4 sequences obtained from different strains (including vaccine strains) and found that various strains showed a high degree of homology in this region. Thus, we conclude that SP4 is a promising serological testing protein for use in the field.

Validation of a serum neutralization test for detection of antibodies specific to cyprinid herpesvirus 3 in infected common and koi carp (Cyprinus carpio).

Cyprinid herpesvirus 3 (CyHV-3) is the aetiological agent of a serious infective, notifiable disease affecting common carp and varieties. In survivors, infection is generally characterized by a subclinical latency phase with restricted viral replication. The CyHV-3 genome is difficult to detect in such carrier fish that represent a potential source of dissemination if viral reactivation occurs. In this study, the analytical and diagnostic performance of an alternative serum neutralization (SN) method based on the detection of CyHV-3-specific antibodies was assessed using 151 serum or plasma samples from healthy and naturally or experimentally CyHV-3-infected carp. French CyHV-3 isolate 07/108b was neutralized efficiently by sera from carp infected with European, American and Taiwanese CyHV-3 isolates, but no neutralization was observed using sera specific to other aquatic herpesviruses. Diagnostic sensitivity, diagnostic specificity and repeatability of 95.9%, 99.0% and 99.3%, respectively, were obtained, as well as a compliance rate of 89.9% in reproducibility testing. Neutralizing antibodies were steadily detected in infected carp subjected to restrictive or permissive temperature variations over more than 25 months post-infection. The results suggest that this non-lethal diagnostic test could be used in the future to improve the epidemiological surveillance and control of CyHV-3 disease.

Standardization of serum neutralization assay of Japanese encephalitis virus (Nakayama NIH strain) on BHK-21 (Cl-13) cell line.

Potency testing of Japanese encephalitis (JE) vaccine has been a complex process since its inception. To overcome difficulties encountered therein, an alternative assay, serum neutralization test (SNT), using Baby Hamster Kidney 21 cell line, has been standardized. The antibody response generated against JE vaccine was quantified and the assay was found to be sensitive and specific enough with significant accuracy and precision. On analysis of cell count, a cell concentration of 1.5 x 104 was selected as the optimum, since concentrations above and below this resulted in problems of confluent monolayer formation and incomplete monolayer formation. Incubation time has also been standardized for measuring cytopathic effect (CPE). Out of the four different time points selected, 90 min was found to be adequate for 50% reduction in the amount of CPE. The accuracy of SNT assay is explained in terms of fiducial limits at 95% level. Inter- and intra-assay reproducibility testing was also performed. A comparison of potency of JE vaccine by plaque reduction neutralization test (PRNT) and SNT method was conducted and it was found that SNT can be a reliable approach for estimating the potency of JE vaccine. The results of this study throw a light on the utility of SNT assay for the potency estimation of JE vaccine in routine practice.

Low specificity of 2 tetanus rapid tests in Cambodia.

OBJECTIVES: Rapid testing for tetanus on serum or blood allows for an immediate evaluation of individual protection against tetanus in developed countries, using a "single step" immunochromatographic technique using tetanus toxoid. The specificity of these tests, compared to the reference method for tetanus, mouse serum neutralization testing, has however never been assessed in these countries, due to the difficulty to perform serum neutralization titration in mice, because of animal testing bioethical regulations. POPULATION AND METHODS: A collection of sera from adult volunteers in Cambodia, living in rural environment, was tested for tetanus antibodies by ELISA in France, and by mouse serum neutralization in Vietnam. This allowed estimating the sensitivity and specificity of 2 rapid tetanus tests, available on the market: TQS™ and Tetanotop™. RESULTS: The sensitivity of these tests was adequate, compared to mice serum neutralization test, for a test threshold of 0.01 IU/mL, (100% for TQS™, 91% for Tetanotop™), but their specificity was very low (1% for TQS™ and 13% for Tetanotop™). CONCLUSION: The results prove that these rapid tests for the assessment of individual protection against tetanus should not be used in the adult rural Cambodian population.

Validation of γ-radiation and ultraviolet as a new inactivators for foot and mouth disease virus in comparison with the traditional methods.

AIM: The present work deals with different methods for foot and mouth disease virus (FMDV) inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV) in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines. MATERIALS AND METHODS: FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21) and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA). Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine. RESULTS: The effect of heat, gamma radiation, and UV on the ability of replication of FMDV "O/pan Asia, A/Iran05, and SAT-2/2012" was determined through BHK cell line passage. Each of the 9 virus aliquots titer 10(8) TCID50 (3 for each strain) were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain) contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance) for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy) were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2) was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) with gamma radiation were 55-60 and 45 kGy, respectively. Inactivation of FMDV with binary was 20, 24 and 16 hr for O/pan Asia, A/Iran05, and SAT-2/2012, respectively while inactivation by (BEI+FA) was determined after 18, 19 and 11 hr for O/pan-Asia, A/Iran 05, and SAT-2/2012, respectively. The antigenicity of control virus before inactivation was 1/32, it was not changed after inactivation in case of gamma radiation and (BEI+FA) and slightly decrease to 1/16 in case of binary and declined to 1/2, 1/4 in case of heat and UV inactivation, respectively. The immune response induced by inactivated FMD vaccines by gamma radiation and (BEI+FA) lasted to 9 months post-vaccination, while the binary only still up to 8 months post-vaccination but heat and UV-inactivated vaccines were not effective. CONCLUSION: Gamma radiation could be considered a good new inactivator inducing the same results of inactivated vaccine by binary with formaldehyde (BEI+FA).

Herpes bovino tipo 1 (BHV 1): I. Sorologia de rebanhos com problemas reprodutivos / Bovine herpesvirus type 1 (BHV-1): I. Sorologic survey in herds with reproductive problems

A presença de anticorpos neutralizantes contra o BHV-1, foi pesquisada pelo teste de soroneutralização (SN) em 2.341 soros, dos quais 747 apresentaram resultado positivo, representando 31,9 por cento de bovinos infectados pelo BHV-1. Os soros foram enviados de 112 propriedades da Região Sul, sendo na maioria rebanhos de gado de corte com problemas reprodutivos. Foram detectados bovinos sorologicamente positivos em 80 propriedades, representando 71,3 por cento, demonstrando a expressiva disseminação do vírus nos rebanhos desta região.

Serum antibodies against BHV-1 were studied, by the serum neutralization test, in cattle from Southem Brazil. Samples were collected from 2341 cattie from 112 farms that had reprodution problems. Positive results were obtained in 747 (31.9) cattie from 80 (71.31 percent) farms, given evidence of the expressivo vírus dissemination in cattie from this region.