Molecular characterization of Brazilian FeLV strains in São Luis, Maranhão Brazil.

The feline leukemia virus (FeLV) belongs to the Retroviridae family and Gammaretrovirus genus, and causes a variety of neoplastic and non-neoplastic diseases in domestic cats (Felis catus), such as thymic and multicentric lymphomas, myelodysplastic syndromes, acute myeloid leukemia, aplastic anemia, and immunodeficiency. The aim of the present study was to carry out the molecular characterization of FeLV-positive samples and determine the circulating viral subtype in the city of São Luís, Maranhão, Brazil, as well as identify its phylogenetic relationship and genetic diversity. The FIV Ac/FeLV Ag Test Kit (Alere™) and the commercial immunoenzymatic assay kit (Alere™) were used to detect the positive samples, which were subsequently confirmed by ELISA (ELISA - SNAP® Combo FeLV/FIV). To confirm the presence of proviral DNA, a polymerase chain reaction (PCR) was performed to amplify the target fragments of 450, 235, and 166 bp of the FeLV gag gene. For the detection of FeLV subtypes, nested PCR was performed for FeLV-A, B, and C, with amplification of 2350-, 1072-, 866-, and 1755-bp fragments for the FeLV env gene. The results obtained by nested PCR showed that the four positive samples amplified the A and B subtypes. The C subtype was not amplified. There was an AB combination but no ABC combination. Phylogenetic analysis revealed similarities (78% bootstrap) between the subtype circulating in Brazil and FeLV-AB and with the subtypes of Eastern Asia (Japan) and Southeast Asia (Malaysia), demonstrating that this subtype possesses high genetic variability and a differentiated genotype.

Biomarkers and occurrences of heavy metals in sediment and the bioaccumulation of metals in crabs (Ucides cordatus) in impacted mangroves on the Amazon coast, Brazil.

In this study, we analyzed biomarkers and heavy metals in Ucides cordatus specimens caught in mangrove areas [A1 = reference (low impact area); A2, A3 and A4 = port complex (potentially impacted area)] of the Amazonian northern coast of Brazil. Sediments and crab muscles sampled from the potentially impacted mangroves showed high levels of metals. Additionally, catalase and glutathione S-transferase enzymes in the gills and hepatopancreas of the collected crabs were elevated in crabs from A2, A3 and A4 relative to those from A1. The histological characteristics of the gills and hepatopancreas differed in crabs collected from A2, A3 and A4 compared with those collected from A1. The crabs were larger and heavier in the rainy season in A1 and A3 and heavier in the dry season in A4. Heavy metal analyses of sediments, crab muscles and biological responses indicated that the animals are subjected to stress levels differentiated in the mangroves due to a gradient (A4>A3>A2>A1) of anthropogenic pressure in São Marcos Bay. In conclusion, the analyses of metals in the sediment and in the muscles of crabs, as well as the biochemical biomarker and histological analyses, suggest that crabs from mangroves in the port complex region are subject to pollutants that compromise their health.

Brucella-associated cervical bursitis in cattle.

Bovine brucellosis poses a risk to human health and causes serious economic losses for the animal industry. This report describes the use of different diagnostic methods for the diagnosis of brucellosis in cattle affected by cervical bursitis from a slaughterhouse located in São Luís, Maranhão, Brazil. Serum samples from a total of 47 cattle with bursitis were collected and submitted to the Rose Bengal Test (RBT), and RBT-positive samples were further confirmed by the 2-mercaptoethanol (2-ME) assay. RBT indicated 85.1% (40/47) of positive samples, from which 78.7% (37/47) were confirmed by 2-ME. Immunohistochemistry detected Brucella spp. in 34.0% (16/47) of tissues with bursitis. PCR and/or bacterial isolation demonstrated that 63.8% (30/47) of samples were positive and morphologically compatible with Brucella sp. All colonies suggestive of Brucella sp. were confirmed by PCR. Isolates were further characterized by PCR Multiplex AMOS-ENHANCED, which indicated that the isolates corresponded to biovar 1, 2, 4 (43.33%). This study evidences an association between cervical bursitis and Brucella spp. infection in cattle, and that different biovars of Brucella circulate in bovine herds in Maranhão.

Detection of Brucella sp. infection through serological, microbiological, and molecular methods applied to buffaloes in Maranhão State, Brazil.

The aim of the current study is to diagnose Brucella spp. infection using methods such as serology, bacterial isolation, and molecular analysis in buffaloes bred in Maranhão State. In order to do so, 390 samples of buffalo serum were subjected to serological tests, to Rose Bengal Plate Test (RBPT) and to 2-mercaptoethanol (2-ME) combined with slow agglutination test (SAT). Vaginal swabs were collected from seropositive animals and subjected to bacterial isolation and to generic PCR. According to the serological test, 16 animals had a positive reaction to the confirmatory test (2-ME/SAT). As for bacterial isolation, three samples resulted in the isolation of Brucella spp.-characteristic colonies, which were confirmed through PCR. These results confirmed Brucella spp. infection in the buffalo herd from Maranhão State.

Transcription of non-classic major histocompatibility complex (MHC) class I in the bovine placenta throughout gestation and after Brucella abortus infection.

Transcription of non-classical major histocompatibility complex class I (MHC-I) was assessed in the bovine placenta throughout gestation. Additionally, the effect of Brucella abortus infection on expression of non-classical MHC-I was also evaluated using a chorioallantoic membrane explant model of infection. The non-classical MHC-I genes MICB and NC3 had higher levels of transcription in the intercotyledonary region when compared to the placentome, which had higher levels of transcription at the second trimester of gestation. NC1 and classical MHC-I had very low levels of transcription throughout gestation. Trophoblastic cells of B. abortus-infected chorioallantoic membrane explants had an increase in transcription of non-classical MHC-I at 4h post infection. Therefore, this study provides an analysis of non-classical MHC-I transcription at different stages of gestation and different placental tissues, and during B. abortus infection. These findings provide additional knowledge on immune regulation in placental tissues, a known immune-privileged site.

Bovine trypanosomiasis an emerging disease in Maranhão State-Brazil.

In South American countries, bovine trypanosomiasis is caused mainly by Trypanosoma vivax. Among the infected animals, bovines are considered more susceptible, and this susceptibility varies among breeds. To determine the occurrence of T. vivax in Maranhão State, Brazil, a total of 559 cattle blood samples were collected for molecular and parasitological studies. On São Luís Island, no parasites were observed in the parasitological exam; however, with the polymerase chain reaction (PCR) method, three samples (1.06%) were positive. In four municipalities that compose the Pedreiras Basin, 3.39% of the animals were positive on the parasitological exam, and 6.21% of animals were positive by PCR. This finding demonstrates that PCR is more sensitive and confirms that the method is very useful in epidemiological surveys. A further interesting point is that molecular studies clearly define the differences in surface glycoproteins and antigenic variants.