Respiratory illness in young and adult cattle caused by bovine viral diarrhea virus subgenotype 2b in singular and mixed bacterial infection in a BVDV-vaccinated dairy herd.

Bovine respiratory disease (BRD) is a common global health problem in dairy cattle. The definitive diagnosis of BRD is complex because its etiology involves several predisposing and determining factors. This report describes the etiology of a BRD outbreak in a dairy herd in the mesoregion of Central Eastern Paraná, which simultaneously affected young (calves and heifers) and adult (cows) Holstein-Friesian cattle. Nine biological samples, consisting of five lung samples from two cows and three suckling calves, and four nasal swab samples from heifers, were used for etiological diagnosis. The nucleic acids extracted from lung fragments and nasal swabs were subjected to PCR and RT-PCR assays for partial amplification of the genes of five viruses [bovine viral diarrhea virus (BVDV), bovine alphaherpesvirus 1 (BoAHV1), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus 3 (BPIV-3), and bovine coronavirus (BCoV)] and four bacteria (Mycoplasma bovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni) involved in the etiology of BRD. All nine biological samples from the animals with BRD tested negative for BoAHV1, BRSV, BPIV-3, BCoV, and H. somni. Therefore, the involvement of these microorganisms in the etiology of BRD outbreak can be ruled out. It was possible to identify the presence of BVDV and M. bovis in singular and mixed infections of the lower respiratory tract in cattle. BVDV was also identified in two nasal swabs: one as a single etiological agent and the other in association with two bacteria (P. multocida and M. haemolytica). The phylogenetic analysis conducted in the nucleotide sequence of the 5'UTR region and Npro gene of the BVDV amplicons demonstrated that the BVDV field strains of this BRD outbreak belong to subgenotype 2b. To the best of our knowledge, this is the first report of BVDV-2b involvement in the etiology of BRD in Brazil. Finally, it is necessary to highlight that the cattle were obtained from an open dairy herd with biannual vaccinations for BVDV-1a and - 2a.

Herd-level based seroprevalence and associated factors for Toxoplasma gondii in cows in the state of Paraíba, Northeastern Brazil / Soroprevalência em nível de rebanho e fatores associados para Toxoplasma gondii em vacas no estado da Paraíba, Nordeste do Brasil

We aimed to determine the herd and animal levels seroprevalence and associated factors for Toxoplasma gondii infections in cattle from the state of Paraíba, Northeastern Brazil. Herds (n = 434) and cows aged ≥ 24 months (n = 1,895) were randomly selected, and serum samples were tested with the immunofluorescence antibody test (IFAT) using as cutoff of 64. Of the 434 farms investigated, 197 had at least one seropositive cow (prevalence of 49.0%; 95% CI = 44.3%-53.8%), and the prevalence at animal level was 18.0% (95% CI = 5.3%-21.1%). The antibody titers ranged from 64 to 1024, with the most frequent titers being 64 (10.8%) and 128 (3.7%). The risk factors identified were property located in Sertão region (odds ratio [OR] = 3.07), property located in Agreste/Zona da Mata regions (OR = 2.00), animal purchasing (OR = 2.68), herd size of 34-111 animals (OR = 2.91) and herd size > 111 animals (OR = 6.97). The results suggest the wide distribution of T. gondii infections in cattle throughout the state of Paraíba, and the risk factors identified are not possible to correct.(AU)

Objetivou-se determinar a soroprevalência do rebanhos e de animais e os fatores associados à infecção por Toxoplasma gondii em bovinos do estado da Paraíba, Nordeste do Brasil. Rebanhos (n = 434) e vacas com idade ≥ 24 meses (n = 1.895) foram selecionados aleatoriamente, e as amostras de soro foram testadas com o teste de imunofluorescência (RIFI), usando-se como ponto de corte 64. Das 434 fazendas investigadas, 197 tiveram pelo menos uma vaca soropositiva (prevalência de 49%; IC 95% = 44,3%-53,8%), e a prevalência em nível de animais foi de 18% (IC 95% = 5,3%-21,1%). Os títulos de anticorpos variaram de 64 a 1024, sendo os títulos mais frequentes 64 (10,8%) e 128 (3,7%). Os fatores de risco identificados foram na propriedade localizada na região do Sertão ("odds ratio" [OR] = 3,07), na propriedade localizada na região do Agreste/Zona da Mata (OR = 2,00), na compra de animais (OR = 2,68), no tamanho do rebanho de 34-111 animais (OR = 2,91) e no tamanho do rebanho > 111 animais (OR = 6,97). Os resultados sugerem a ampla distribuição de infecções por T. gondii em bovinos em todo o estado da Paraíba, e os fatores de risco identificados não são passíveis de correção.(AU)

Association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of taurine heifers / Associação entre infecção crônica por Anaplasma marginale e Babesia spp. e parâmetros hematológicos de novilhas taurinas

The aim of this study was to investigate the association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of pregnant and non-pregnant taurine heifers. Blood samples from 94 females were collected on the first day (D-10) of timed artificial insemination (TAI) protocol and on pregnancy diagnosis (D+34). Hematological parameters were determined and compared between pregnant (PG) and non-pregnant (NPG) heifers, and within group at different sampling days. Real-time PCR (qPCR) was used to determine A. marginale and Babesia bovis infection, and for absolute quantification of Babesia spp. between PG and NPG groups. Correlation analysis was performed between the number of gDNA copies (CN) of Babesia spp. and hematological parameters. On D-10, mean hemoglobin concentration was higher for NPG, and hematocrit and total plasma protein were higher on D+34 for both groups. There was no difference in Babesia spp. CN between groups. In the first qPCR, all heifers were positive for A. marginale and B. bovis. Significant correlations were found between hemoglobin and erythrocyte and between hemoglobin and hematocrit (r = 0.8082 and r = 0.3009, respectively). Low levels of A. marginale and Babesia spp. did not affect hematological parameters of chronically infected pregnant and non-pregnant taurine heifers.(AU)

O objetivo deste estudo foi investigar a associação entre infecção crônica por Anaplasma marginale e Babesia spp. e parâmetros hematológicos de novilhas taurinas prenhes e não prenhes. Sangue de 94 fêmeas foi coletado no primeiro dia (D-10) do protocolo de inseminação artificial em tempo fixo (IATF) e no diagnóstico de gestação (D+34). Parâmetros hematológicos foram comparados entre novilhas prenhes (PG) e não prenhes (NPG) e dentro dos grupos entre dias de coleta. Usando-se PCR em tempo real (qPCR), determinou-se a infecção por A. marginale e Babesia bovis e quantificação absoluta de Babesia spp. Entre os grupos PG e NPG. A análise de correlação foi realizada entre o número de cópias (CN) de Babesia spp. e parâmetros hematológicos. No D-10, a concentração de hemoglobina foi maior para NPG e hematócrito, e proteína plasmática total foram maiores em D+34 para ambos os grupos. Não houve diferença para CN de Babesia spp. entre os grupos. Na primeira qPCR, todas as novilhas foram positivas para A. marginale e B. bovis. Correlações significativas foram encontradas entre hemoglobina/eritrócito e hemoglobina/hematócrito (r=0,8082 e r=0,3009, respectivamente). Baixos níveis de A. marginale e Babesia spp. não afetaram os parâmetros hematológicos de novilhas taurinas prenhes e não prenhes cronicamente infectadas.(AU)