Whole genome sequencing of low pathogenicity avian influenza virus (H6N2) detected from a Brazilian teal (Amazonnetta brasiliensis) in Brazil, 2023.

The whole genome sequence of a low pathogenicity avian influenza virus (H6N2) was sequenced from a Brazilian teal (Amazonetta brasiliensis) in Brazil, 2023. Phylogenetic analysis of the whole genome revealed a distinct genome pertaining to South American LPAIV from 2014 to 2016, indicating extensive circulation among South American wild birds.

Prolonged SARS-CoV-2 Infection and Intra-Patient Viral Evolution in an Immunodeficient Child.

BACKGROUND: With the progression of the Coronavirus disease pandemic, the number of mutations in the viral genome has increased, showing the adaptive evolution of severe acute respiratory syndrome coronavirus 2 in humans and intensification in transmissibility. Long-term infections also allow the development of viral diversity. In this study, we report the case of a child with severe combined immu presenting a prolonged severe acute respiratory syndrome coronavirus 2 infection. We aimed to analyze 3 naso-oropharyngeal swab samples collected between August and December 2021 to describe the amino acid changes present in the sequence reads that may have a role in the emergence of new viral variants. METHODS: The whole genome from clinical samples was sequenced through high throughput sequencing and analyzed using a workflow to map reads and then find variations/single-nucleotide polymorphisms. In addition, the samples were isolated in cell culture, and a plaque forming units assay was performed, which indicates the presence of viable viral particles. RESULTS: The results obtained showed that the virus present in all samples is infectious. Also, there were 20 common mutations among the 3 sequence reads, found in the ORF1ab and ORF10 proteins. As well, a considerable number of uncommon mutations were found. CONCLUSIONS: In conclusion, we emphasize that genomic surveillance can be a useful tool to assess possible evolution signals in long-term patients.

31st Brazilian Online Society for Virology (SBV) 2020 Annual Meeting.

The year 2020 was profoundly marked by the emergence and spread of SARS-CoV-2, causing COVID-19, which represents the greatest pandemic of the 21st century until now, and a major challenge for virologists in the scientific and medical communities. Increased numbers of SARS-CoV-2 infection all over the world imposed social and travel restrictions, including avoidance of face-to-face scientific meetings. Therefore, for the first time in history, the 2020 edition of the Brazilian Society of Virology (SBV) congress was totally online. Despite the challenge of the new format, the Brazilian society board and collaborators were successful in virtually congregating more than 921 attendees, which was the greatest SBV participant number ever reached. Seminal talks from prominent national and international researchers were presented every night, during a week, and included discussions about environmental, basic, animal, human, plant and invertebrate virology. A special roundtable debated exclusively new data and perspectives regarding COVID-19 by some of the greatest Brazilian virologists. Women scientists were very well represented in another special roundtable called "Young Women Inspiring Research", which was one of the most viewed and commented section during the meeting, given the extraordinary quality of the presented work. Finally, SBV offered the Helio Gelli Pereira award for one graduate and one undergraduate student, which has also been a fruitful collaboration between the society and Viruses journal. The annual SBV meeting has, therefore, reached its goals to inspire young scientists, stimulate high-quality scientific discussion and to encourage global collaboration between virologists.

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Seroprevalence of Bovine Adenovirus and Enterovirus Antibodies Reveals Different Infection Dynamics in Cattle Herds

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil.Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Sout

Production and characterization of a Brazilian candidate antigen for Hepatitis E Virus genotype 3 diagnosis.

Hepatitis E, caused by hepatitis E virus (HEV), is a viral infectious pathology of great importance in the public health. Hepatitis E outbreaks were registered in developing countries with poor or no sanitation, where drinking water was contaminated with fecal material, but also in many industrialized countries probably due to consumption of HEV-positive swine meat. In this study, we present the development and characterization of a recombinant antigen from ORF2 HEV genotype 3. Viral RNA was extracted from swine feces infected with the native virus. A total of 267 residues from the C-terminal ORF2((394-661)) coding sequence were cloned into the pET20a vector and expressed in Escherichia coli ER2566. Recombinant protein was purified by liquid chromatography and the fragment obtained a 98% homology against other human or swine HEV genotype 3 ORF2 sequences. Wistar rats were inoculated with ORF2p, developing antibodies able to recognize both the homologous antigen and the native HEV genotype 3 ORF2 present in infected stool. In parallel, HEV-negative swine were experimentally challenged with HEV genotype 3. ORF2 was detected by PCR 14 days post-inoculation in three-fourth piglets' feces and one week later by dot blot. In conclusion, this study proved the immunogenic and antigenic properties of the recombinant protein ORF2p.

Seroprevalence of Hepatitis B and C markers at the population level in the municipality of Caxias do Sul, southern Brazil

Chronic viral hepatitis are main public health problems worldwide. Data about the seroprevalence to Hepatitis B and C viruses (HBV e HCV) at the population level are scarce on Brazil and especially for the Southern region of the country. The seroprevalence to HBV and HBC antigens was evaluated on a large portion of the population of the municipality of Caxias do Sul (427,858 inhabitants), Brazil. A total of 60,604 individual serum samples collected from 2008 to 2011 were screened for HBV surface antigen (HBsAg) and for antibodies against HBsAg; anti HCV antibodies were measured by ELISA (Enzyme Linked Immunosorbent Assay). Overall, 1.63% of the individuals were positive for HBsAg and 1.43% showed seropositivity to HCV. From the total, 31,749 samples were analyzed for HBsAg and 28,855 for HCV. For HBsAg, 519 samples showed positive (1.63%) while the results for 37 patients (0.12%) remained inconclusive. For the anti-HCV test, 412 individuals (1.43%) showed positive. From the positive samples for HBsAg 216 (50.6%) were from male individuals whereas for anti-HCV the seroprevalence was slightly higher for females 216 (52.4%). The higher prevalence for both hepatitis viruses were found among individuals at the age group of 40 to 59 years and the lower levels of positivity for both HBV and HBC were among children and teenagers.

Seroprevalence of Hepatitis B and C markers at the population level in the municipality of Caxias do Sul, southern Brazil

Chronic viral hepatitis are main public health problems worldwide. Data about the seroprevalence to Hepatitis B and C viruses (HBV e HCV) at the population level are scarce on Brazil and especially for the Southern region of the country. The seroprevalence to HBV and HBC antigens was evaluated on a large portion of the population of the municipality of Caxias do Sul (427,858 inhabitants), Brazil. A total of 60,604 individual serum samples collected from 2008 to 2011 were screened for HBV surface antigen (HBsAg) and for antibodies against HBsAg; anti HCV antibodies were measured by ELISA (Enzyme Linked Immunosorbent Assay). Overall, 1.63% of the individuals were positive for HBsAg and 1.43% showed seropositivity to HCV. From the total, 31,749 samples were analyzed for HBsAg and 28,855 for HCV. For HBsAg, 519 samples showed positive (1.63%) while the results for 37 patients (0.12%) remained inconclusive. For the anti-HCV test, 412 individuals (1.43%) showed positive. From the positive samples for HBsAg 216 (50.6%) were from male individuals whereas for anti-HCV the seroprevalence was slightly higher for females 216 (52.4%). The higher prevalence for both hepatitis viruses were found among individuals at the age group of 40 to 59 years and the lower levels of positivity for both HBV and HBC were among children and teenagers.

Detecção molecular de vírus da bronquite infecciosa em plantéis de avós, matrizes e frangos de corte no Rio Grande do Sul e Mato Grosso

Infectious bronchitis virus (IBV, Avian Coronavirus) from chickens belongs to group 3 of the family Coronaviridae and causes respiratory and renal disorders in broilers. Vaccination using live vaccines is generally performed in mothers and grandmothers, as well as often in flocks for slaughter. The vaccines used in Brazil are usually from serogroup Massachusetts and based on standard samples of the virus at passages H120 and H52. It is common that after vaccination the vaccine virus is detected by isolation in embryonated eggs or by molecular methods for up to four weeks. After, there is usually no virus detection and any IBV found may represent recirculation of the vaccine virus in the flock or the introduction of a new strain. In this study, to evaluate the circulation of the virus in poultry flocks and breeders in the state of Rio Grande do Sul and Mato Grosso do Sul, 240 samples were collected from tracheas and kidneys of birds from 48 flocks, and (20 biological samples / 4 flocks) from grandmothers (80 samples/16 flocks) and mothers (140 samples/28 flocks) from broilers, which were analyzed in pools of five samples. All animals were vaccinated and samples were collected around 2-48 weeks after vaccination. The presence of IBV was determined with the aid of a polymerase chain reaction "nested" gene-directed protein S1, standardized in this study. From the 48 samples tested, 14 were positive: 5 were from birds vaccinated after less than 4 weeks and 9 were from birds vaccinated more than four weeks should be wild viruses or represent the recirculation of the vaccine virus.

O vírus da Bronquite Infecciosa das galinhas (VBI) pertence ao grupo 3 da família Coronaviridae e é o causador de desordens respiratórias e renais em frangos de corte. A vacinação com vacinas vivas é praticada em matrizes e avós e muitas vezes também nos plantéis destinados ao abate. As vacinas utilizadas no Brasil são usualmente do sorogrupo Massachusetts e baseadas nas amostras H120 e H52. É comum que após a vacinação o vírus vacinal seja detectado por isolamento em ovos embrionados ou por métodos moleculares por até 4 semanas. Após essa data, normalmente, não há detecção de vírus e o VBI, quando encontrado, pode representar recirculação do vírus vacinal no plantel ou a introdução de uma nova cepa do vírus. No presente estudo, para avaliar a circulação do vírus em plantéis de frangos e reprodutoras nos estados do Rio Grande do Sul e Mato Grosso do Sul, foram coletadas 240 traqueias e rins de aves de 48 plantéis, sendo (20 exemplares/4 plantéis) de avós, (80 exemplares/16 plantéis) de matrizes e (140 exemplares/28 plantéis) de frangos de corte, as quais foram analisadas em misturas de cinco amostras. Todos os animais eram vacinados e as amostras foram coletadas ao redor de 2 a 48 semanas após a vacinação. A presença de VBI foi determinada com auxílio de uma reação em cadeia da polimerase tipo nested, direcionada ao gene da proteína S1, padronizada neste estudo. Das 48 amostras testadas, 14 resultaram positivas: cinco foram oriundas de aves vacinadas há menos de quatro semanas na data da coleta e nove eram de amostras de aves vacinadas há mais de quatro semanas, o que pode ser devido à recirculação do vírus vacinal ou mesmo introdução de vírus selvagem nos plantéis.

Detecção molecular de vírus da bronquite infecciosa em plantéis de avós, matrizes e frangos de corte no Rio Grande do Sul e Mato Grosso

Infectious bronchitis virus (IBV, Avian Coronavirus) from chickens belongs to group 3 of the family Coronaviridae and causes respiratory and renal disorders in broilers. Vaccination using live vaccines is generally performed in mothers and grandmothers, as well as often in flocks for slaughter. The vaccines used in Brazil are usually from serogroup Massachusetts and based on standard samples of the virus at passages H120 and H52. It is common that after vaccination the vaccine virus is detected by isolation in embryonated eggs or by molecular methods for up to four weeks. After, there is usually no virus detection and any IBV found may represent recirculation of the vaccine virus in the flock or the introduction of a new strain. In this study, to evaluate the circulation of the virus in poultry flocks and breeders in the state of Rio Grande do Sul and Mato Grosso do Sul, 240 samples were collected from tracheas and kidneys of birds from 48 flocks, and (20 biological samples / 4 flocks) from grandmothers (80 samples/16 flocks) and mothers (140 samples/28 flocks) from broilers, which were analyzed in pools of five samples. All animals were vaccinated and samples were collected around 2-48 weeks after vaccination. The presence of IBV was determined with the aid of a polymerase chain reaction "nested" gene-directed protein S1, standardized in this study. From the 48 samples tested, 14 were positive: 5 were from birds vaccinated after less than 4 weeks and 9 were from birds vaccinated more than four weeks should be wild viruses or represent the recirculation of the vaccine virus.

O vírus da Bronquite Infecciosa das galinhas (VBI) pertence ao grupo 3 da família Coronaviridae e é o causador de desordens respiratórias e renais em frangos de corte. A vacinação com vacinas vivas é praticada em matrizes e avós e muitas vezes também nos plantéis destinados ao abate. As vacinas utilizadas no Brasil são usualmente do sorogrupo Massachusetts e baseadas nas amostras H120 e H52. É comum que após a vacinação o vírus vacinal seja detectado por isolamento em ovos embrionados ou por métodos moleculares por até 4 semanas. Após essa data, normalmente, não há detecção de vírus e o VBI, quando encontrado, pode representar recirculação do vírus vacinal no plantel ou a introdução de uma nova cepa do vírus. No presente estudo, para avaliar a circulação do vírus em plantéis de frangos e reprodutoras nos estados do Rio Grande do Sul e Mato Grosso do Sul, foram coletadas 240 traqueias e rins de aves de 48 plantéis, sendo (20 exemplares/4 plantéis) de avós, (80 exemplares/16 plantéis) de matrizes e (140 exemplares/28 plantéis) de frangos de corte, as quais foram analisadas em misturas de cinco amostras. Todos os animais eram vacinados e as amostras foram coletadas ao redor de 2 a 48 semanas após a vacinação. A presença de VBI foi determinada com auxílio de uma reação em cadeia da polimerase tipo nested, direcionada ao gene da proteína S1, padronizada neste estudo. Das 48 amostras testadas, 14 resultaram positivas: cinco foram oriundas de aves vacinadas há menos de quatro semanas na data da coleta e nove eram de amostras de aves vacinadas há mais de quatro semanas, o que pode ser devido à recirculação do vírus vacinal ou mesmo introdução de vírus selvagem nos plantéis.

Detecção molecular de vírus da bronquite infecciosa em plantéis de avós, matrizes e frangos de corte no Rio Grande do Sul e Mato Grosso

Infectious bronchitis virus (IBV, Avian Coronavirus) from chickens belongs to group 3 of the family Coronaviridae and causes respiratory and renal disorders in broilers. Vaccination using live vaccines is generally performed in mothers and grandmothers, as well as often in flocks for slaughter. The vaccines used in Brazil are usually from serogroup Massachusetts and based on standard samples of the virus at passages H120 and H52. It is common that after vaccination the vaccine virus is detected by isolation in embryonated eggs or by molecular methods for up to four weeks. After, there is usually no virus detection and any IBV found may represent recirculation of the vaccine virus in the flock or the introduction of a new strain. In this study, to evaluate the circulation of the virus in poultry flocks and breeders in the state of Rio Grande do Sul and Mato Grosso do Sul, 240 samples were collected from tracheas and kidneys of birds from 48 flocks, and (20 biological samples / 4 flocks) from grandmothers (80 samples/16 flocks) and mothers (140 samples/28 flocks) from broilers, which were analyzed in pools of five samples. All animals were vaccinated and samples were collected around 2-48 weeks after vaccination. The presence of IBV was determined with the aid of a polymerase chain reaction "nested" gene-directed protein S1, standardized in this study. From the 48 samples tested, 14 were positive: 5 were from birds vaccinated after less than 4 weeks and 9 were from birds vaccinated more than four weeks should be wild viruses or represent the recirculation of the vaccine virus.

O vírus da Bronquite Infecciosa das galinhas (VBI) pertence ao grupo 3 da família Coronaviridae e é o causador de desordens respiratórias e renais em frangos de corte. A vacinação com vacinas vivas é praticada em matrizes e avós e muitas vezes também nos plantéis destinados ao abate. As vacinas utilizadas no Brasil são usualmente do sorogrupo Massachusetts e baseadas nas amostras H120 e H52. É comum que após a vacinação o vírus vacinal seja detectado por isolamento em ovos embrionados ou por métodos moleculares por até 4 semanas. Após essa data, normalmente, não há detecção de vírus e o VBI, quando encontrado, pode representar recirculação do vírus vacinal no plantel ou a introdução de uma nova cepa do vírus. No presente estudo, para avaliar a circulação do vírus em plantéis de frangos e reprodutoras nos estados do Rio Grande do Sul e Mato Grosso do Sul, foram coletadas 240 traqueias e rins de aves de 48 plantéis, sendo (20 exemplares/4 plantéis) de avós, (80 exemplares/16 plantéis) de matrizes e (140 exemplares/28 plantéis) de frangos de corte, as quais foram analisadas em misturas de cinco amostras. Todos os animais eram vacinados e as amostras foram coletadas ao redor de 2 a 48 semanas após a vacinação. A presença de VBI foi determinada com auxílio de uma reação em cadeia da polimerase tipo nested, direcionada ao gene da proteína S1, padronizada neste estudo. Das 48 amostras testadas, 14 resultaram positivas: cinco foram oriundas de aves vacinadas há menos de quatro semanas na data da coleta e nove eram de amostras de aves vacinadas há mais de quatro semanas, o que pode ser devido à recirculação do vírus vacinal ou mesmo introdução de vírus selvagem nos plantéis.

Analysis of isotype-specific antibody responses to bovine herpesviruses 1.1 and 1.2a allows to estimate the stage of infection

Specific IgM, IgA, IgG1, IgG2, as well as neutralizing antibody responses were evaluated in sera of calves experimentally infected with two isolates of bovine herpesvirus type 1 (BoHV1) of distinct subtypes (subtype 1, BoHV1.1; subtype 2a, BoHV-1.2a). No significant differences were observed in the antibody responses induced by each BoHV-1 subtype. The antibody responses following primary acute infection were characterized by an increase in specific IgM and IgA levels between days 2 and 14 post inoculation (pi). IgG1 was detected from days 11 to 30 pi. IgG2 was detected on the sample taken on day 30 pi. Reactivation of infection following dexamethasone administration induced a significant rise in IgA levels, whereas IgG1 and IgG2 levels, which were at high levels from the beginning of the reactivation process, showed a slight alteration after corticosteroid treatment. These results suggest that it is possible to estimate the dynamics of BoHV-1 infections with basis on the analysis of class- and subclass-specific antibody responses. Such information may be particularly useful for the study of the kinetics of the infection in a herd and to aid in the adoption of appropriate control measures..