Genetic characterization of the parvovirus full-length VP2 gene in domestic cats in Brazil.

Feline parvovirus (FPV) and canine parvovirus (CPV) are over 98% identical in their DNA sequences, and the new variants of CPV (2a/2b/2c) have gained the ability to infect and replicate in cats. The aim of this study was to determine the genetic diversity in the VP2 gene of parvovirus strains circulating in domestic cats in Brazil during a 10-year period (2008-2017). For parvovirus screening, specific PCR was performed, and 25 (34.7%) of 72 cats tested positive. The PCR-positive samples were further subjected to full-length VP2 sequencing (1755 bp), and eight sequences (36%) were characterized as FPV, seven (28%) as CPV-2a and (32%) nine (36%) as CPV-2b. One sequence (RJ1085/11) showing typical CPV amino acid (aa) at residues 80 R, 93 N, 103 A, 232 I, and 323 N could not be characterized at this time. The sequences in this study displayed aa changes previously described for FPV (A14T, A91S, I101T, N564S, and A568G) from cats and CPV-2a/2b (S297N and Y324L) from dogs. However, the Y324L mutation has not yet been reported in any CPV-2a/2b strains from cats. Phylogenetic analysis supported the division of these sequences into two well-defined clades, clade 1 for FPV and clade 2 for CPV2a/2b. Unusually, the sequence RJ1085/11 was grouped separately. Two recombination breakpoints were detected by Bootscan and 3Seq methods implemented in the RDP4. This study is the first report of CPV-2a/2b in cats in Brazil. The detection of FPV strains with mutations characteristic of CPV indicates that Brazilian FPV strains have undergone genetic changes.

Molecular detection of porcine circovirus (PCV2 and PCV3), torque teno swine virus 1 and 2 (TTSuV1 and TTSuVk2), and histopathological findings in swine organs submitted to regular slaughter in Southeast, Brazil.

Porcine circovirus 2 and 3 (PCV2 and PCV3) and torque teno sus virus 1 and 2 (TTSuV1 and TTSuVk2) are important pathogens in pig associated with post-weaning mortality, different clinical syndromes in adults (PCVAD), and a decrease of average daily weight gain (PCV2-SI) but little is known about the infection on asymptomatic pigs. The aim of this study was to evaluate the presence of PCV2, PCV3, TTSuV1, and TTSuVk2 in swine organ samples from asymptomatic pigs slaughtered in Espírito Santo State, South-eastern Brazil, through molecular detection and histopathological analysis. Nested PCR showed the presence of PCV2 DNA in 10% (14/140), PCV3 in 13.6% (19/140), TTSuV1 in 12.9% (18/140), and TTSuVk2 in 30% (42/140) of the tissue samples. All four viruses were detected in the lung, kidney, lymph node, and liver. TTSuVk2 was detecded in 30% (42/140), PCV3 in 13.6% (19/140), TTSuV1 in 12.9% (18/140), and PCV2 in 10% (14/140) of the samples. Single infections were observed in 30.7% (43/140), while co-detections in the same tissue occurred in 15.7% (22/140). The most frequent combinations were TTSuV1/TTSuVk2 in 31.8% (7/22), PCV2/TTSuVk2 in 18.1% (4/22), and PCV2/PCV3/TTSuVk2 in 13.6% (3/22). Lymphocyte depletion was associated with TTSuVk2 infection (p = 0.0041) suggesting that TTSuVK2 plays an induction of PMWS-like lymphoid lesions in pigs. The data obtained in this study show that PCV2, PCV3, TTSuV1, and TTSuVk2 are related to infection in asymptomatic animals with different tissue lesions, and the molecular diagnosis for these pathogens should be considered in the sanitary monitoring of herds.

O circovírus suíno 2 e 3 (PCV2 e PCV3) e os Torque Teno vírus suínos 1 e 2 (TTSuV1 e TTSuVk2) são patógenos importantes na suinocultura associados a diferentes síndromes clínicas e morte de leitões pós desmame (PCVAD) e redução no ganho diário de peso (PCV2-SI). Entretanto, pouco se sabe sobre a circulação desses agentes e o impacto da infecção em porcos assintomáticos. O objetivo deste estudo foi avaliar a presença de PCV2, PCV3, TTSuV1 e TTSuVk2 em amostras de órgãos de suínos assintomáticos abatidos no estado do Espírito Santo, região sudeste do Brasil, por meio de detecção molecular e análise histopatológica. A análise tecidual por nested PCR mostrou a presença de DNA de PCV2 em 14 (10%), PCV3 em 19 (13,6%), TTSuV1 em 18 (12,9%) e de TTSuVk2 em 42 (30%) das amostras. Todos os quatro vírus foram detectados no pulmão, rim, nódulo linfático e fígado TTSuVk2 foi detectado em 30% das amostras teciduais (42/140), PCV3 em 13.6% (19/140), TTSuV1em 12.9% (18/140), e o PCV2 em 10% (14/140. Mono infecções foram observadas em 30.7% (43/140) das amostras enquanto infecções múltiplas observadas em 15.7% (22/140 das amostras de tecido). As combinações mais frequentes foram TTSuV1/TTSuVk2 em 31.8% (7/22), PCV2/TTSuVk2 em 18.1% (4/22), e PCV2/PCV3/TTSuVk2 em 13.6% (3/22). A depleção de linfócitos foi associada à infecção por TTSuVk2 (p = 0,0041) e esses achados sugerem que TTSuKV2 desempenha uma indução de lesões linfoides semelhantes a PMWS em porcos. Os dados obtidos neste estudo mostram que PCV2, PCV3, TTSuV1 e TTSuVk2 estão relacionados à infecção em animais assintomáticos com lesões teciduais diversas, e sugerem que o diagnóstico molecular para esses patógenos deve ser considerado no monitoramento sanitário dos rebanhos.

Molecular characterization of feline calicivirus variants from multicat household and public animal shelter in Rio de Janeiro, Brazil

ABSTRACT The aim of this study was to perform the molecular characterization of conserved and variable regions of feline calicivirus capsid genome in order to investigate the molecular diversity of variants in Brazilian cat population. Twenty-six conjunctival samples from cats living in five public short-term animal shelters and three multicat life-long households were analyzed. Fifteen cats had conjunctivitis, three had oral ulceration, eight had respiratory signs (cough, sneeze and nasal discharge) and nine were asymptomatic. Feline calicivirus were isolated in CRFK cells and characterized by reverse transcription PCR target to both conserved and variable regions of open reading frame 2. The amplicons obtained were sequenced. A phylogenetic analysis along with most of the prototypes available in GenBank database and an amino acid analysis were performed. Phylogenetic analysis based on both conserved and variable region revealed two clusters with an aLTR value of 1.00 and 0.98 respectively and the variants from this study belong to feline calicivirus genogroup I. No association between geographical distribution and/or clinical signs and clustering in phylogenetic tree was observed. The variants circulating in public short-term animal shelter demonstrated a high variability because of the relatively rapid turnover of carrier cats constantly introduced of multiple viruses into this location over time.

Molecular characterization of feline calicivirus variants from multicat household and public animal shelter in Rio de Janeiro, Brazil.

The aim of this study was to perform the molecular characterization of conserved and variable regions of feline calicivirus capsid genome in order to investigate the molecular diversity of variants in Brazilian cat population. Twenty-six conjunctival samples from cats living in five public short-term animal shelters and three multicat life-long households were analyzed. Fifteen cats had conjunctivitis, three had oral ulceration, eight had respiratory signs (cough, sneeze and nasal discharge) and nine were asymptomatic. Feline calicivirus were isolated in CRFK cells and characterized by reverse transcription PCR target to both conserved and variable regions of open reading frame 2. The amplicons obtained were sequenced. A phylogenetic analysis along with most of the prototypes available in GenBank database and an amino acid analysis were performed. Phylogenetic analysis based on both conserved and variable region revealed two clusters with an aLTR value of 1.00 and 0.98 respectively and the variants from this study belong to feline calicivirus genogroup I. No association between geographical distribution and/or clinical signs and clustering in phylogenetic tree was observed. The variants circulating in public short-term animal shelter demonstrated a high variability because of the relatively rapid turnover of carrier cats constantly introduced of multiple viruses into this location over time.

Clinical aspects and weight gain reduction in swine infected with porcine circovirus type 2 and torque teno sus virus in Brazil.

Simultaneous Porcine circovirus type 2 (PCV-2) and Torque teno sus virus (TTSuV) infections have been reported around the world, generally linked to severe infections. In the present study, 257 swine plasma samples from 31 swine herds located in Brazil, were PCR screened for PCV-2 and TTSuV-1/2 and correlated with clinical data. PCV-2 was detected in 25%, followed by 38.1% and 42.4% of TTSuV-1 and TTSuV-2, respectively. Co-infections of two or three viruses were found in 32.3% of samples. PCV-2 was more frequently detected in the growing (p=0.030) and finishing phases (p=0.0005) while TTSuV-2 in the nursery (p=0.009). Only TTSuV-1 was statistically associated to clinical disease (multiple signs), in combination or not with PCV-2 or TTSuV-2 (p=0.015). PCV-2/TTSuV co-infections were more frequently related to weight gain reduction in comparison to mono-infections (p=0.049) and no-infections (p=0.027), and also in animals with (p=0.011) or without (p=0.037) clinical signs, being the nursery the most affected phase (p=0.025). Our results uphold the pathogenic potential of TTSuV in naturally infected pigs and the clinical/economical impact of this agent, especially in co-infections. Studies addressing the physiopathological mechanisms of simultaneous infections are needed.

Molecular characterization of canine coronavirus strains circulating in Brazil.

To characterize canine coronavirus (CCoV) circulating in diarrheic puppies in Brazil, 250 fecal samples collected between 2006 and 2012 were tested. By using RT-PCR to partially amplify the M gene, CCoV RNA was detected in 30 samples. Sequence analysis of the M protein grouped eight strains with CCoV-I and another 19 with CCoV-II prototypes. To genotype/subtype the CCoV strains and assess the occurrence of single or multiple CCoV infections, RT-PCR of the S gene was performed, and 25/30 CCoV-positive strains amplified with one or two primer pairs. For 17/25 samples, single infections were detected as follows: six CCoV-I, nine CCoV-IIa and two CCoV-IIb. Eight samples were positive for more than one genotype/subtype as follows: seven CCoV-I/IIa and one CCoV-I/IIb. Sequence analysis revealed that the CCoV-I and IIa strains shared high genetic similarity to each other and to the prototypes. The Brazilian strains of CCoV-IIb displayed an aminoacid insertion that was also described in CCoV-IIb-UCD-1 and TGEV strains. Among the 25 CCoV-positive puppies, five had a fatal outcome, all but one of which were cases of mixed infection. The current study is the first reported molecular characterization of CCoV-I, IIa and IIb strains in Brazil.

Characterization of parvoviruses from domestic cats in Brazil.

To characterize Feline parvovirus (FPV) circulating in domestic cats in Brazil, 51 fecal samples from unvaccinated domestic cats were collected during 2004-2005. Six parvoviruses were characterized by hemagglutination (HA) assay at different pH values and temperatures and by polymerase chain reaction (PCR) using different pairs of primers. However, data obtained from HA and PCR did not allow the discrimination between FPV and Canine parvovirus (CPV). Two regions of the VP2 capsid gene (1,171-bp fragment) involved in controlling canine and feline host range were sequenced; 9 synonymous and 10 non-synonymous nucleotide substitutions were detected. All samples were confirmed as FPV by nucleotide sequencing, but 3 feline samples had amino acid changes at residues 93, 375, and 426, which are present in canine strains. The phylogenetic tree built based on nucleotide sequences showed that Brazilian feline samples form a cluster distinct from other parvoviruses deposited in GenBank. Taken together, the findings reinforce the importance of monitoring the continuous evolution of CPV and FPV in the feline population in Brazil.