Valeria Moojen

Viroses confundíveis com febre aftosa

Diseases to be considered in the differential diagnosis of foot-and-mouth disease are reviewed. The main aspects relating to the diagnosis of vesicular stomatitis, bovine virus diarrhea, malignant catarrhal fever, bovine herpesvirus 1 and 5, andem ulcerative stomatitis associated with bovine parvovirus are described. Bluetongue, that probably occurs in Rio Grande do Sul because antibodies to the virus have been detected in cattle and sheep; is refered. Bovine ulcerative mammilitis, reported in other Brazilian States, rinderpest, reported and eradicated in the State of Sao Paulo in 1921, and popular stomatitis are also cited, and so are two exotic diseases: vesicular exanthema and swine vesicular disease.

DETECTION OF BOVINE RESPIRATORY SYNCYTIAL VIRUS IN CALVES OF RIO GRANDE DO SUL, BRAZIL

During 20 months of the 1987-1990 period, lung tissue samples from 351 calves were obtained at a slaughterhouse. These calves were from counties nearby Porto Alegre. The direct and indirect fluorescent antibody tests (FAT) using polyclonal and monoclonal antibody conjugates were performed on frozen lung sections. Eighteen (5.13%) of the calf lung samples were positive for the Bovine Respiratory Syncytial Virus (BRSV). The BRSV was isolated from FAT positive samples.

Manifestação clínico-patológica de infecção natural pelo Vírus Respiratório Sincicial Bovino (BRSV) em bovinos de criação extensiva no Rio Grande do Sul, Brasil

The clinical aspects as well as the pathology, microbiology and serology of a natural Bovine Respiratory Syncytial (BRSV) infection of bovine in a herd of 600 beef cattle kept under extensive management in the State of Rio Grande do Sul, Brazil, are described. Clinically two animals had chronic cough and severe dyspnea when forced to mild physical exercise. These two animals were euthanatized and post-morten examination was performed. The macroscopic changes were of pulmonary origin, such as disseminated alveolar emphysema, focal atelectasis and marked interlobular septal thickening. The fluorescent antibody test on lung cryostat sections was positive to BRSV for both animals, and it was negative to PI-3 virus, BVDV and BHV. The BRSV was isolated from the lung of one of the animals on MDBK, and was also identified by fluorescent antibody test. No association with Chlamydia psittaci was found by ELISA performed on lung tissues. The histopathology showed syncytial cells, chronic emphysema, peribronchiolar muscle layer hypertrophy and squamous metaplasia of bronchial and bronchiolar epithelia. The serology to detect antibodies to BRSV resulted in 79% of positives from the first specimen collection. In this group of young animals some of them had a cough. The second samples collected 6 months later were from animals of different age groups resulting in 17.3% of positives. This is the first report on clinical BRSV infection in Brazil.

Caracterização molecular parcial do gene gag de amostras do vírus da artrite-encefalite caprina (CAEV) isoladas de animais naturalmente infectados no Rio Grande do Sul, Brasil

The gag gene of 5 CAEV samples, isolated from naturally infected goats from Rio Grande do Sul, Brazil, were analised by PCR and restriction endonuclease (DdeI, HaeIII e NdeI) digestion. Fragments of about 600 bp were amplified by PCR and submitted to enzymatic digestion. The patterns observed were compared with the corresponding gag sequences from 6 small ruminant lentiviruses. The results obtained allowed the separation of 3 distinct groups. The restriction fragment profiles observed were different from those previously described.

Detecção da infecção pelo vírus da artrite-encefalite caprina: imunodifusão em ágar e reação em cadeia da polimerase com "primers" degenerados

The purpose of this work was to analyse serum and blood cells from caprine origin to detect antibody and proviral DNA of caprine arthritis encephalitis virus (CAEV), respectively. Agar gel immunodiffusion (AGID) and polymerase chain reaction (PCR) with degenerated primers were used. Samples of different geographical regions were analysed: 39 from Mato Grosso do Sul (MS), 19 from Sao Paulo (SP), 22 from Ceara (CE) including 10 from Canada (imported animals), providing a total of 80 samples. The results obtained by AGID and PCR were discordants, as 25 samples were detected as seropositive, while 16 infected animals were detected by PCR. On the other hand, PCR allowed the identification of infected animals that did not have detectable antibodies by AGID: eight samples from MS and one from CE. Different aspects related to these discordant results are discussed.

Imunofluorescência utilizando isolados brasileiros no diagnóstico sorológico de infecção por lentivírus em caprinos

Small ruminant lentiviruses (SRLV) are distributed worldwide and cause persistent infections in sheep and goats. The purpose of this work was to develop an indirect immunofluorescent antibody (IFA) test using Brazilian SRLV isolates for serological diagnosis of infection in goats. The IFA test was compared in its sensitivity and specificity to the AGID test in which Maedi-Visna WLC-1 strain was used as antigen. Ovine synovial secondary cell cultures infected with two goat SRLV isolates (CAEV UFRGS/Br-2 and CAEV UFRGS/Br-5) were used for the IFA. Goat serum samples (n = 239) were tested by the two tests. The AGID test detected antibodies in 129 (53.9%) serum samples. A higher number of animals was considered positive for the IFA. However, different results were obtained depending on the isolate used for the antigen preparation. When CAEV UFRGS/Br-2 was used as antigen, 216 (90.3%) serum samples tested positive, against 213 (89.1%) with CAEV UFRGS/Br-5. There was no significant statistical difference between the antigens prepared with these two isolates. The IFA had sensitivity of 94.6% and 96.9%, and specificity of 14.5 % and 20%, when CAEV UFRGS/Br-2 and CAEV UFRGS/Br-5 were used as antigens, respectively. These results demonstrate that the IFA with antigens prepared with Brazilian SRLV isolates may play an important a role as a complementary serological test for the diagnosis of infections by these agents.