Immunogenicity of an inactivated vaccine for intravaginal application against bovine alphaherpesvirus type 5 (BoHV-5).

The present study was carried out to evaluate the intravaginal vaccine potential against bovine alphaherpesvirus type 5 (BoHV-5). Sixty three cows were divided into seven groups (n: 9) and inoculated intravaginally (VA) or intramuscularly (IM) with inactivated BoHV-5, associated with the recombinant B subunit of the heat-labile enterotoxin of E. coli (rLTB), 2-hydroxyethylcellulose (Drug Delivery System A - DDS-A) or Poloxamer 407 (Drug Delivery System B - DDS-B) as follows: G1 (DDS-A + BoHV-5 + rLTB), G2 (DDS-A + BoHV-5), G3 (DDS-B + BoHV-5 + rLTB), G4 (DDS-B + BoHV-5), G5 (BoHV-5 + rLTB), G6 (Negative control) e G7 (Positive control). The local and systemic humoral responses were measured by indirect ELISA (IgA and IgG) and serum neutralization tests, and the cellular response was measured by a quantitative direct ELISA (IL-2 and IFN-Gamma). The results showed the group inoculated by the IM route, G5, demonstrated the highest levels of IgG in the vaginal mucosa among the experimental groups (p < 0.05). In the groups tested with polymers (G1 and G3) in the vaginal mucosa, even higher levels of IgG were seen in comparison to the positive control (G7; p < 0.01). Higher levels of IgA were also noted in relation to the other groups (p < 0.05) on days 30, 60 and 90 post-inoculations. The groups G1 and G3 also provided higher titers of neutralizing antibodies (Log2) in relation to other treatments (p < 0.01) 90 days after inoculation. In the nasal mucosa, there was an increase in the levels of IgA and IgG with the use of vaccines from groups G1 and G3, in relation to the positive control, G7 (p < 0.05) at 60 and 90 days after the first inoculation. Moreover, neutralizing antibodies titers were detected at 60 and 90 days by serum neutralization. The inclusion of the evaluated polymers resulted in a superior response (p < 0.05) of immunoglobulins and IL-2 and IFN-Gamma in relation to the treatment using only rLTB (G5). This data demonstrates the capabilities of a vaccine with an intravaginal application in cattle to stimulate a local and systemic immune response.

Microscopic alterations in Fasciola hepatica treated with the essential oils of Pelargonium graveolens and Citrus aurantium.

Fasciolosis is one of the most important parasitic diseases in animal health, affecting mainly ruminants, causing economic and productivity losses. This study aimed to evaluate the in vitro ovicidal and adulticidal activity of essential oils (EOs) from Pelargonium graveolens (geranium) and Citrus aurantium (sour orange) on Fasciola hepatica. Performed Gas Chromatography of EOs P. graveolens and C. aurantium, with major compound, citronellol (31.37 %) and limonene (93.89 %), respectively. For the cytotoxicity assay, the sour orange EO showed to be promising when used in lower concentrations. For the ovicidal tests, the eggs were incubated with geranium EOs at concentrations from 4.5 to 0.03375 mg/mL and sour orange at concentrations from 4.25 to 0.031875 mg/mL, along with controls. The viable eggs were counted on the 14th day post-incubation. Adult forms of F. hepatica were incubated containing the EOs and observed for 24 h after treatment, as well as the control groups. Later the specimens were fixed for histological analysis. Geranium and sour orange EOs in trematode eggs at the concentrations tested were 100 % effective in inactivating hatching (p < 0.05) when compared to the untreated control. In the adulticidal test, the essential oil of P. graveolens at both concentrations tested (0.0675 and 0.03375) within 15 h, promoted the death of flukes. For C. aurantium, 18 h was enough to inactivate all specimens, up to a concentration of 0.06375. The histological analysis, observed the accumulation of liquid in the tegument in the specimens incubated in C. aurantium and P. graveolens, with vacuolization in the tegument and spines, preventing externalization. The results of the study present OEs with efficient ovicidal and adulticidal activity.

Identification of Clade E Avipoxvirus in Brazil.

Avian poxvirus (APV) is an enveloped double-stranded DNA virus that affects many domestic and wild birds worldwide. APVs are classified into three clades (A to C), represented by fowlpox (FP) virus (clade A), canarypox virus (clade B), and psittacinepox virus (clade C), although two additional clades (D and E) have been proposed. In this study, a tumorlike skin lesion found in a domestic fowl was submitted for molecular diagnosis of Avipoxvirus by PCR and sequencing. The phylogenetic analysis revealed that the amplified segment of the corelike 4b protein and polymerase genes clustered in clade E. The APVs in clade E were previously reported from outbreaks in Hungary (flock of turkeys) and in Mozambique (layer chickens), associated with a possible vaccine failure to protect against clade E viruses. To our knowledge, this report is the first identification of clade E in this country, providing new information about host range and genetic diversity of APVs in Brazil, and may represent a potential risk of FP disease outbreaks in commercial poultry.

Reporte de caso- Identificación del Avipoxvirus clado E en Brasil. El poxvirus aviar (APV) es un virus de ADN bicatenario envuelto que afecta a muchas aves domésticas y silvestres en todo el mundo. Los poxvirus aviares se clasifican en tres clados (A, B y C), representados por el virus de la viruela aviar (FP) (clado A), el virus de la viruela del canario (clado B) y el virus de la viruela de los psitácidos (clado C), aunque dos clados adicionales (D y E) han sido propuestos. En este estudio, una lesión cutánea similar a un tumor encontrada en una gallina doméstica fue sometida a diagnóstico molecular de Avipoxvirus por PCR y secuenciación. El análisis filogenético reveló que el segmento amplificado de los genes de la proteína del centro 4b y de la polimerasa se agruparon en el clado E. Los poxvirus aviares en el clado E se reportaron previamente de brotes en Hungría (parvada de pavos) y en Mozambique (gallinas de postura), asociados con una posible falla de la vacuna para proteger contra los virus del clado E. De acuerdo con el conocimiento de los autores, este informe es la primera identificación del clado E en este país, brindando nueva información sobre el rango de hospedadores y la diversidad genética de poxvirus aviares en Brasil, y puede representar un riesgo potencial de brotes de viruela aviar en aves comerciales.

In vitro anti-Pythium insidiosum activity of biogenic silver nanoparticles.

Pythium insidiosum belongs to the phylum Oomycota. It is capable of infecting mammals causing a serious condition called pythiosis, which affects mainly horses in Brazil and humans in Thailand. The objective of the present study was to verify the in vitro anti-P. insidiosum activity of a biogenic silver nanoparticle (bio-AgNP) formulation. The in vitro assays were evaluated on P. insidiosum isolates (n = 38) following the M38-A2 protocol. Damage to the P. insidiosum hyphae ultrastructure was verified by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bio-AgNP inhibition concentrations on P. insidiosum isolates ranged from 0.06 to 0.47 µg/ml. It was observed through SEM that P. insidiosum hyphae treated showed surface roughness, as well as cell walls with multiple retraction areas, loss of continuity, and rupture in some areas. The TEM of treated hyphae did not differentiate organelle structures; also, the cellular wall was rarefied, showing wrinkled and partly ruptured borders. The bio-AgNP evaluated has excellent in vitro anti-P. insidiosum activity. However, further studies on its in vivo action are necessary as so to determine the possibility of its use in the treatment of the disease in affected hosts.

Combined use of ELISA and Western blot with recombinant N protein is a powerful tool for the immunodiagnosis of avian infectious bronchitis.

BACKGROUND: The avian infectious bronchitis virus (IBV) remains a significant source of loss in the poultry industry and early diagnosis is required to prevent the disease from spreading. This study examined the combined use of an ELISA and Western blot (WB) to detect antibodies against the nucleocapsid protein (N) of IBV. The coding sequence for N was amplified by RT-PCR and expressed in Escherichia coli. A soluble recombinant N protein (rN) of approximately 50 kDa was obtained. A total of 389 sera were tested against the rN in ELISA and the results were compared with those of the commercial IDEXX IBV Ab test. ELISA-rN achieved a 90.34% sensitivity and 90.16% specificity. WB confirmed all false negative sera in ELISA-rN or IDEXX test as truly positive. The current study indicate that the combined use of rN in ELISA and WB is a powerful tool for the immunodiagnosis of avian infectious bronchitis. METHODS: Constructed recombinant pAE/n expression vectors were used to transform E. coli BL21(DE3) Star competent cells (Invitrogen). The rN of infectious bronchitis virus was purified by affinity chromatography using HisTrap HP 1 mL columns pre-packed with pre-charged Ni Sepharose in the ÄKTAprime Automated Liquid Chromatography system (GE Healthcare). A total of 389 serum samples from chickens were used to develop and evaluate the ELISA-rN test. To standardize the indirect ELISA development, serum dilutions (1:100, 1:200 and 1:400) and different concentrations of purified rN antigen (50, 100 and 200 ng/well) were tested. Positive and negative sera for IBV were used as controls. The results were compared with those obtained from a commercial kit. Serum samples scored as negative with the commercial kit but as positive with the ELISA-rN were further analysed by Western blot analyses using the rN protein as an antigen. The results of the ELISA-rN were compared to the commercial kit results using receiver-operating characteristics curves, area under the curve, and confidence intervals with the software GraphPad Prism version 6.0 for Windows (GraphPad Software, USA). RESULTS: The expected cDNA fragment of approximately 1240 bp was successfully amplified by PCR using primers designed to select for the coding region of the N protein. The rN was expressed as a soluble protein to avoid the refolding steps and, after purification a yield of 10 mg/L of rN was obtained. The SDS-PAGE results demonstrated the presence of two distinct bands that had a molecular mass of approximately 45 and 50 KDa. Out of 244 sera that scored positive in the commercial ELISA IDEXX IBV Ab Test, 220 were also positive in the ELISA-rN, yielding an ELISA-rN test sensitivity of 90.16%. Out of 145 sera that scored negative in the IDEXX IBV Ab Test, 131 also scored negative in the ELISA-rN, indicating a specificity of 90.34%. Sera that tested negative in the ELISA-rN and positive in the commercial test also reacted with the rN protein in Western blot. CONCLUSIONS: The association between the ELISA and Western blot techniques developed in this study with a subunit of IBV (rN) were able to detect antibodies that the commercial ELISA did not detect suggesting that the ELISA-rN has greater sensitivity.

Ovicidal in vitro activity of 2-aryl-3-(2-morpholinoethyl)thiazolidin-4-ones and 2-aryl-3-(3-morpholinopropyl)thiazolidin-4-ones against Fasciola hepatica (Linnaeus, 1758).

Although there is a variety of biological activity reports regarding compounds derived from thiazolidin-4-ones, no data related to ovicidal activity against trematodes, particularly Fasciola hepatica are available. Since there are reports about anthelmintic resistance in F. hepatica, new drugs are required. Thus, this study evaluated ovicidal action in vitro against F. hepatica eggs in two systematic series of thiazolidin-4-ones: 2-aryl-3-(2-morpholinoethyl)thiazolidin-4-ones (1a-h) and 2-aryl-3-(3-morpholinopropyl)thiazolidin-4-ones (2a-h) at different concentrations (20, 2, 0.2, 0.02 and 0.002 µg/ml). The egg hatch assay (EHA) was used to evaluate the ovicidal action property of such compounds. In addition, potential negative effects of the compounds on metabolic activity of bovine kidney (MDBK) cells were evaluated by determining mitochondrial dehydrogenase activity. The eggs used in the EHA were obtained from parasites removed from the liver of cattle, which were discarded by slaugh after sanitary inspection. The results of EHA showed that compounds 2a-h exhibited ovicidal activity, especially compounds 2b which showed 90% ovicidal activity and viability of 93% MDBK cells at the concentration of 2 µg/ml; and 2e with 96-99% ovicidal activity at 0.2 µg/ml, 0.02 µg/ml and 0.002 µg/ml. The results show the potential of compound 2b to continue the studies in the production of new compounds with anthelmintic action.

Coronavirus canino (CCoV) em cães vacinados e não vacinados domiciliados em Pelotas, RS / Canine coronavirus (CCoV) in dogs vaccinated and unvaccinated domiciliated in Pelotas, RS, Brazil

Coronavírus canino (CCoV) foi relatado como causa de doença entérica principalmente em cães jovens. Nesse estudo, para investigar imunidade e exposição ao CCoV, foi estimado a frequência de anticorpos em 121 cães de Pelotas, sul do Brasil, pelo teste de soro-neutralização (SN): 22 não haviam sido vacinados, 69 haviam sido vacinados com pelo menos uma dose, e 30 possuíam histórico de vacinação desconhecido. Foram detectados anticorpos em 47,8% (33/69) dos cães vacinados, em 45,5% (10/22) dos não vacinados, e em 43,3% (13/30) dos cães com histórico de vacinação desconhecido. Não houve associação significativa entre os anticorpos e sexo, idade, habitação e estação da coleta. Os resultados confirmam a circulação do CCoV entre essa população de cães e indicam que a infecção acomete população significativa de animais. A grande proporção de cães vacinados soronegativos indica falha da vacina em indução de anticorpos neutralizantes, sugerindo que as imunizações para CCoV devam ser reavaliadas. Os autores por meio de seus dados indicam ainda a necessidade de posteriores estudos para avaliar o impacto da infecção causada pelo CCoV, bem como para avaliar e  propor mediadas preventivas.

Canine coronavirus (CCoV) has been reported causing enteric disease mainly in young pups. In this study, to investigate immunity and exposure to CCoV, was estimated the frequency of serum antibodies to CCoV in 121 dogs in the Pelotas, South of Brazil, by serum neutralization test (SN): 22 had not been vaccinated, 69 had been vaccinated at least once, and 30 had unknown vaccination history. Antibodies were present in 47,8% (33/69) of the vaccinated dogs, in 45,5% (10/22) of the unvaccinated, and in 43,3% (13/30) of the dogs with unknown historical vaccination. There was no significant relationship between these antibodies and sex, age, habitat, and season of collection. The results proved the circulation of the CCoV among this dog population and indicated that the infection affects a significant group of animals. The large proportion of seronegative vaccinated dogs indicates failure of CCoV vaccine in inducing neutralizing antibodies, suggesting that immunizations to CCoV should be reevaluated. The authors indicate the need for further studies in order to evaluate the impact of the infection caused by CCoV, as well as to propose and evaluate preventive measures.

Adjuvant effect of green propolis on humoral immune response of bovines immunized with bovine herpesvirus type 5.

Despite recent technological advances in vaccine production, most vaccines depend on the association with adjuvant substances. In this study, propolis, which has been attracting the attention of researchers due to its bioactive properties, was evaluated as an immunological adjuvant. The association of 40mg/dose of an ethanolic extract of green propolis with an inactivated oil vaccine against bovine herpesvirus type 5 (BoHV-5), resulted in a significant increase (P<0.01) in the neutralizing antibody levels, comparing to the bovines that received the same vaccine without propolis. Besides, propolis increased the percentage of animals with high antibody titers (above 32). Phenolic compounds such as artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) and the derivatives of cinnamic acid besides other flavonoid substances were abundant in the propolis extract used, and they could be the main substances with adjuvant action. The effect of the green propolis extract on the humoral immune response can be exploited in the development of new vaccines.

Evaluation of blood on filter paper to detection and quantification of the antibo¬dies to newcastle disease virus / Avaliação do uso de sangue em papel-filtro para detecção e quantificação de anticorpos para o vírus da doença de newcastle

The present study describes the evaluation of a filter paper blood sampling technique for assessment of the level of antibodies against the Newcastle disease virus (NDV) by hemagglutination inhibition (HI) test. Blood samples were collected from ninety eigth chickens with a known history of vaccination against NDV and analyzed by HI method. The blood was impregnated onto Whatman no. 1 filter paper with 3cm2 and also collected in tubes for obtaining serum. The papers were stored at room temperature and tested within fourty five days. The resulting sensitivity, specificity, positive predictive value and negative predictive value of the filter paper HI compared to serum HI was 89%, 73%, 76% and 87%, respectively. It was found index precision of the 80% and the correlation coefficient r = 0.81%. The overall average geometrical titer of antibodies was 33.1 and 33.6 in eluates and in sera, respectively. Association between the two methods was found to be highly significant (p 0.001) when analyzed by Fishers test. The results indicate the potential use of filter paper blood sampling technique as an alternative to serum for detection of the antibodies against NDV. KEY-WORDS: Chicken, hemagglutination inhibition, serology.

O presente trabalho descreve a utilização de sangue total em papel-filtro para avaliação dos níveis de anticorpos específicos contra o vírus da doença de Newcastle (NDV) através da técnica de inibição da hemaglutinação (HI). Coletaram-se e analisaram-se por HI amostras de sangue de noventa e oito galinhas, com um histórico conhecido de vacinação contra o NDV HI. O sangue foi impregnado em papel-filtro Wathman n 1 com 3cm2 e também coletado em tubos para a obtenção de soro. Armazenaram-se os papéis à temperatura ambiente e procedeu-se a sua análise num período de até quarenta e cinco dias. A sensibilidade, a es¬pecificidade, o valor preditivo positivo e o valor preditivo negativo do HI mediante o uso de papel-filtro, comparado com o HI em que se utilizou soro, foram de 89%, 73%, 76% e 87 %, respectivamente. Detectaram-se um índice de pre¬cisão de 80% e um coeficiente de correlação r = 0,81%. O título médio geométrico de anticorpos foi 33,1% e 33,6 para eluídos de papel-filtro e os soros, respectivamente. A asso¬ciação entre os dois métodos foi altamente significativa (p 0.001) quando analisada pelo teste de Fisher. Os resultados indicam o potencial da utilização do sangue em papel-filtro como uma alternativa ao soro para detecção de anticorpos contra o NDV. PALAVRAS-CHAVES: Galinha, inibição da hemaglutinação, sorologia.

Prevalence and factors associated with bovine viral diarrhea virus infection in South of Rio Grande do Sul / Prevalência e fatores associados à infecção pelo vírus da diarréia viral bovina na região Sul do Rio Grande do Sul

This study was performed in order to estimate the prevalence of bovine viral diarrhea virus (BVDV), and to determine the main factors related to the prevalence of the infection in cattle of Santa Vitória do Palmar and Chuí counties, in Rio Grande do Sul State. Sera were submitted to the serum neutralization test and an epidemiological questionnaire was filled out in each herd to investigate variables that could be associated with this infection. The sera samples were collected in 85 farms, with or without clinical signs of BVDV infection. From 1.734 serum samples examined, 1.150 (66.32%) in 70 (82.35%) herds were positive. Variables that were identified as risk factors to seropositivity were mixed (dairy and beef) herds, extensive production, use of mechanical milking, use of artificial insemination or artificial insemination associated with natural service, use of the maternity unit at calving and absence of veterinarian assistance (P 0.05). The results demonstrate the expressive dissemination of the BVDV in cattle of this region in Rio Grande do Sul.

O presente estudo teve como objetivo estimar a prevalência e determinar os principais fatores associados à infecção pelo vírus da diarréia viral bovina (BVDV) no rebanho bovino dos municípios de Santa Vitória do Palmar e Chuí, na região sul do estado do Rio Grande do Sul. Amostras de soro foram submetidas à prova de soroneutralização e, em cada propriedade avaliada, aplicou-se um questionário epidemiológico para investigar fatores que poderiam estar associados à infecção. As amostras de soro foram coletadas em 85 propriedades, cujos animais apresentavam ou não sinais clínicos de infecção pelo BVDV. Das 1.734 amostras de soro analisadas, 1.150 (66,32%) foram positivas com a detecção de bovinos sorologicamente positivos em 70 (82,35%) propriedades. Dentre os fatores avaliados, exploração mista, criação extensiva, realização de ordenha mecânica, uso de inseminação artificial ou de inseminação artificial associada à monta natural, uso de piquete de parição e ausência de assistência veterinária, apresentaram significância estatística (p 0,05) associada à soropositividade. Os resultados obtidos demonstram a expressiva disseminação do BVDV no rebanho bovino dessa região do Rio Grande do Sul.

Construction and characterization of a bovine herpesvirus 5 mutant with a deletion of the gI, gE and US9 genes

Bovine herpesvirus 5 (BoHV-5) is a important cause of viral encephalitis in cattle in South America. Within the framework of developing a differential vaccine against BoHV-5, a deletion mutant was constructed based on a Brazilian BoHV-5 isolate. The target of the deletions were genes that code proteins implicated in the neurovirulence of BoHV-5, the glycoprotein I (gI), glycoprotein E (gE) and membrane protein US9. To construct the deletion mutant of BoHV-5, the flanking regions of all three genes were cloned in a prokaryotic plasmid. This deletion fragment was co-transfected with the viral DNA into bovine cells. Identification of deletion mutants was performed by immunostaining with an anti-gE monoclonal antibody. One of the gE negative viral populations found was purified, amplified and further examined by restriction endonuclesase analysis of its genomic DNA. The plaque sizes and penetration kinetics of the deletion mutant and wild type viruses were compared. The plaque sizes of the deletion mutant were significantly smaller than those of the parental strain (p = 0.05), but no statistical differences were observed in penetration kinetics. The results indicate that the gI/gE/US9 deletion mutant of BoHV-5 may have a reduced virulence in the host and is still viable enough to be a good candidate for the development of a BoHV-5 vaccine.

O herpesvírus bovino 5 (BoHV-5) é uma causa importante de encefalite viral em bovinos na América do Sul. Buscando o desenvolvimento de uma vacina diferencial contra o BoHV-5, um mutante deletado foi construído com base em um isolado brasileiro deste vírus. O alvo das deleções foram genes que codificam proteínas implicadas na neurovirulência do BoHV-5, a glicoproteína I (gI), a glicoproteína E (gE) e a proteína de membrana US9. Para construir o mutante deletado de BoHV-5, as regiões flanqueadoras dos três genes foram clonadas em um plasmídeo procarioto. Este fragmento de deleção foi co-transfectado com o DNA viral em células de bovinos. A identificação dos mutantes deletados foi feita por meio da técnica de imunoperoxidase com um anticorpo monoclonal anti-gE. Uma das populacões virais gE negativas encontradas foi purificada, amplificada e seu genoma foi examinado por análise de restrição enzimática. Os tamanhos de placas virais e taxas de penetração do vírus mutante foram determinados e comparados com os do vírus selvagem. As placas virais do vírus mutante deletado foram significativamente menores do que as do vírus selvagem (p = 0,05), mas não foram encontradas diferenças significativas quando comparadas as taxas de penetração dos dois vírus. Estes resultados indicam que o vírus mutante deletado gI/gE/US9 de BoHV-5 pode apresentar virulência reduzida e é viável o suficiente para ser um bom candidato para o desenvolvimento de uma vacina contra o BoHV-5.

EVALUATION OF BLOOD ON FILTER PAPER TO DETECTION AND QUANTIFICATION OF THE ANTIBO¬DIES TO NEWCASTLE DISEASE VIRUS / AVALIAÇÃO DO USO DE SANGUE EM PAPEL-FILTRO PARA DETECÇÃO E QUANTIFICAÇÃO DE ANTICORPOS PARA O VÍRUS DA DOENÇA DE NEWCASTLE

The present study describes the evaluation of a filter paper blood sampling technique for assessment of the level of antibodies against the Newcastle disease virus (NDV) by hemagglutination inhibition (HI) test. Blood samples were collected from ninety eigth chickens with a known history of vaccination against NDV and analyzed by HI method. The blood was impregnated onto Whatman no. 1 filter paper with 3cm2 and also collected in tubes for obtaining serum. The papers were stored at room temperature and tested within fourty five days. The resulting sensitivity, specificity, positive predictive value and negative predictive value of the filter paper HI compared to serum HI was 89%, 73%, 76% and 87%, respectively. It was found index precision of the 80% and the correlation coefficient r = 0.81%. The overall average geometrical titer of antibodies was 33.1 and 33.6 in eluates and in sera, respectively. Association between the two methods was found to be highly significant (p 0.001) when analyzed by Fishers test. The results indicate the potential use of filter paper blood sampling technique as an alternative to serum for detection of the antibodies against NDV. KEY-WORDS: Chicken, hemagglutination inhibition, serology.

O presente trabalho descreve a utilização de sangue total em papel-filtro para avaliação dos níveis de anticorpos específicos contra o vírus da doença de Newcastle (NDV) através da técnica de inibição da hemaglutinação (HI). Coletaram-se e analisaram-se por HI amostras de sangue de noventa e oito galinhas, com um histórico conhecido de vacinação contra o NDV HI. O sangue foi impregnado em papel-filtro Wathman n 1 com 3cm2 e também coletado em tubos para a obtenção de soro. Armazenaram-se os papéis à temperatura ambiente e procedeu-se a sua análise num período de até quarenta e cinco dias. A sensibilidade, a es¬pecificidade, o valor preditivo positivo e o valor preditivo negativo do HI mediante o uso de papel-filtro, comparado com o HI em que se utilizou soro, foram de 89%, 73%, 76% e 87 %, respectivamente. Detectaram-se um índice de pre¬cisão de 80% e um coeficiente de correlação r = 0,81%. O título médio geométrico de anticorpos foi 33,1% e 33,6 para eluídos de papel-filtro e os soros, respectivamente. A asso¬ciação entre os dois métodos foi altamente significativa (p 0.001) quando analisada pelo teste de Fisher. Os resultados indicam o potencial da utilização do sangue em papel-filtro como uma alternativa ao soro para detecção de anticorpos contra o NDV. PALAVRAS-CHAVES: Galinha, inibição da hemaglutinação, sorologia.

Evolução da imunidade passiva contra o herpesvírus bovino tipo 1

The aim of the present study was to determine the evolution of the levels of anti-BHV-1 colostral antibodies. Serum samples were obtained at 6, 12 and 24 hours post-birth, weekly through the 63rd day of age, and monthly through the 180rd day. The study utilized the serum neutralization test (SN). The colostral antibodies against BHV-1 declined gradually: the first negativo samples were obseved at day 28, and the geometric mean titer of antibodies (GMT) was estimated to be £1:2 at day 180. These data suggest that serology for BHV-1 (using the SN) should be used only in calves older then six months.

Determinou-se a evolução da imunidade colostral contra o herpesvírus bovino tipo 1 (BHV-1) através de análise de amostras de soro de terneiras coletadas às 6, 12 e 24 horas após o nascimento, semanalmente dos 7 dias até os 63 dias de idade, e mensalmente até 180 dias. O estudo foi realizado através do teste de soro-neutralização (SN). Os anticorpos colostrais declinaram progressivamente. Amostras negativas começaram a aparecer no 28° dia após o nascimento, e aos 180 dias de idade foi estimado que o título médio geométrico de anticorpos (GMT) era £1:2. Sugere-se que para diagnóstico de infecção pelo BHV-1 a prova de SN seja realizada após o 6° mês de idade.

Levantamento sorológico da infecção pelo vírus da leucose bovina nos rebanhos leiteiros do Estado do Rio Grande do Sul, Brasil

Bovine leukosis vírus (BLV) is associated with a persistem infection in cattle that is responsible for serious lasses to the livestock industry. The objective of this study was to determine the prevalence and to analyse some epidemiological aspects of the BLV infection in the dairy herd of the Rio Grande do Sul state. A total of 39.799 blood samples, collected in 4,200 herds from 172 counties, distributed in 9 geographic regions, were tested by the agar-gel immunodiffusion test (AGID) with glycoproteic antigen (glycoprotein gp 51). The sorologic tests showed 3,645 (9.2%) positive; however, the prevalence in the state, when considered about 1% of the population in each region was only, 12.0% (1,295/10,357) and 29.1% (385/1,321) of the herds had at least one seropositive animal. The prevalence ranged from 2.2% (17.8% of the herds) in Uruguaiana to l9.6% (57.85% of the herds) in São Gabriel. Prevalences of 15.5% (41.8% of herds) in the Porto Alegre metropolitan area. 9.9% (64.4%) in Pelotas, 19.4% (42.9%) in Bagé, 9.2% (36.2%) in Santa Rosa, 12.9% (37.8%) in Erexim, 7.1% (26.5%) in Passo Fundo and 8% (33.8%) in Santa Maria were observed. These results show that the BLV infection is widely spread within the Rio Grande do Sul dairy herd. Nevertheless, the overall prevalence is still low if compared to other states and countries and may be compatible with control and eradication efforts.

O vírus da Leucose Enzoótica Bovina (VLB) causa uma infecção persistente em bovinos, sendo responsável por perdas econômicas significativas para a pecuária bovina. O objetivo deste estudo foi determinar a prevalência da infecção pelo VLB no rebanho leiteiro do Estado do Rio Grande do Sul, Brasil e estudar alguns aspectos epidemiológicos da infecção. Um total de 39.799 amostras de soro. coletadas em 4.200 propriedades de 172 municípios, distribuídos em 9 regiões geográficas, foram testadas pela técnica de imunodifusão em gel de ágar (IDGA), com antígeno glicoprotéico (glicoproteína gp 51). Os exames sorológicos revelaram 3.645 (9,2%) amostras positivas. No entanto, a prevalência média do Estado, quando foi considerada aproximadamente 1% da população em cada região, foi de 12,0% (1.295/10.357) e 29,1% (385/1.321) das propriedades apresentaram pelo menos um animal positivo. A prevalência da infecção variou de 2,2% (17,8% das propriedades) em Uruguaiana, a 19,6% (57,8% das propriedades) em São Gabriel. Foram observadas taxas de 15,5% (41.8% das propriedades) na grande Porto Alegre; 9,9% (64,4%) em Pelotas: 19,4% (42,9%) em Bagé; 9,2% (36,2%) na grande Santa Rosa; 12.9% (37,8%) em Erexim; 7,1% (26,5%) em Passo Fundo e 8,0% (33,8%) em Santa Maria. Esses resultados demonstram que a infecção pelo VLB esta amplamente distribuída no rebanho leiteiro do Estado. No entanto, os índices de infecção são relativamente baixos se comparados com índices de outros estados e países e são compatíveis com programas de controle e erradicação.

Levantamento sorológico da infecção pelo vírus da leucose bovina nos rebanhos leiteiros do Estado do Rio Grande do Sul, Brasil

Bovine leukosis vírus (BLV) is associated with a persistem infection in cattle that is responsible for serious lasses to the livestock industry. The objective of this study was to determine the prevalence and to analyse some epidemiological aspects of the BLV infection in the dairy herd of the Rio Grande do Sul state. A total of 39.799 blood samples, collected in 4,200 herds from 172 counties, distributed in 9 geographic regions, were tested by the agar-gel immunodiffusion test (AGID) with glycoproteic antigen (glycoprotein gp 51). The sorologic tests showed 3,645 (9.2%) positive; however, the prevalence in the state, when considered about 1% of the population in each region was only, 12.0% (1,295/10,357) and 29.1% (385/1,321) of the herds had at least one seropositive animal. The prevalence ranged from 2.2% (17.8% of the herds) in Uruguaiana to l9.6% (57.85% of the herds) in São Gabriel. Prevalences of 15.5% (41.8% of herds) in the Porto Alegre metropolitan area. 9.9% (64.4%) in Pelotas, 19.4% (42.9%) in Bagé, 9.2% (36.2%) in Santa Rosa, 12.9% (37.8%) in Erexim, 7.1% (26.5%) in Passo Fundo and 8% (33.8%) in Santa Maria were observed. These results show that the BLV infection is widely spread within the Rio Grande do Sul dairy herd. Nevertheless, the overall prevalence is still low if compared to other states and countries and may be compatible with control and eradication efforts.

O vírus da Leucose Enzoótica Bovina (VLB) causa uma infecção persistente em bovinos, sendo responsável por perdas econômicas significativas para a pecuária bovina. O objetivo deste estudo foi determinar a prevalência da infecção pelo VLB no rebanho leiteiro do Estado do Rio Grande do Sul, Brasil e estudar alguns aspectos epidemiológicos da infecção. Um total de 39.799 amostras de soro. coletadas em 4.200 propriedades de 172 municípios, distribuídos em 9 regiões geográficas, foram testadas pela técnica de imunodifusão em gel de ágar (IDGA), com antígeno glicoprotéico (glicoproteína gp 51). Os exames sorológicos revelaram 3.645 (9,2%) amostras positivas. No entanto, a prevalência média do Estado, quando foi considerada aproximadamente 1% da população em cada região, foi de 12,0% (1.295/10.357) e 29,1% (385/1.321) das propriedades apresentaram pelo menos um animal positivo. A prevalência da infecção variou de 2,2% (17,8% das propriedades) em Uruguaiana, a 19,6% (57,8% das propriedades) em São Gabriel. Foram observadas taxas de 15,5% (41.8% das propriedades) na grande Porto Alegre; 9,9% (64,4%) em Pelotas: 19,4% (42,9%) em Bagé; 9,2% (36,2%) na grande Santa Rosa; 12.9% (37,8%) em Erexim; 7,1% (26,5%) em Passo Fundo e 8,0% (33,8%) em Santa Maria. Esses resultados demonstram que a infecção pelo VLB esta amplamente distribuída no rebanho leiteiro do Estado. No entanto, os índices de infecção são relativamente baixos se comparados com índices de outros estados e países e são compatíveis com programas de controle e erradicação.

Evolução da imunidade passiva contra o herpesvírus bovino tipo 1

The aim of the present study was to determine the evolution of the levels of anti-BHV-1 colostral antibodies. Serum samples were obtained at 6, 12 and 24 hours post-birth, weekly through the 63rd day of age, and monthly through the 180rd day. The study utilized the serum neutralization test (SN). The colostral antibodies against BHV-1 declined gradually: the first negativo samples were obseved at day 28, and the geometric mean titer of antibodies (GMT) was estimated to be £1:2 at day 180. These data suggest that serology for BHV-1 (using the SN) should be used only in calves older then six months.

Determinou-se a evolução da imunidade colostral contra o herpesvírus bovino tipo 1 (BHV-1) através de análise de amostras de soro de terneiras coletadas às 6, 12 e 24 horas após o nascimento, semanalmente dos 7 dias até os 63 dias de idade, e mensalmente até 180 dias. O estudo foi realizado através do teste de soro-neutralização (SN). Os anticorpos colostrais declinaram progressivamente. Amostras negativas começaram a aparecer no 28° dia após o nascimento, e aos 180 dias de idade foi estimado que o título médio geométrico de anticorpos (GMT) era £1:2. Sugere-se que para diagnóstico de infecção pelo BHV-1 a prova de SN seja realizada após o 6° mês de idade.