Elis Lorenzetti

Genetic heterogeneity of wild-type G4P[6] porcine rotavirus strains detected in a diarrhea outbreak in a regularly vaccinated pig herd

Group A rotavirus (RV-A) with short electropherotype was identified by ss-PAGE in a neonatal diarrhea outbreak at a Brazilian pig farm where the sows were regularly vaccinated with a commercial vaccine containing OSU (G5P[7]) and Gottfried (G4P[6]) porcine RV-A (PoRV-A) strains. The ss-PAGE positive stool samples (n=20) were characterized as P[6] genotype by multiplex-nested-RT-PCR assay. The nucleotide analysis of the VP4 gene (VP8*) state that the viruses clustered in P[6] lineages that are also shared by RV-A strains identified in human hosts. Nucleotide analysis of the VP7 gene identified different lineages in G4 including a new lineage tentatively designated IX. The immunological pressure induced by commercial vaccine with a rotavirus containing a G4P[6] genotype of porcine origin (Gottfried strain) might have allowed the selection of PoRV-A strains with characteristics found in RV-A strains isolated of human hosts, such as P[6]-Ie and If, and promoted the selection or emergence of RV-A strains with a new lineage of the G4 genotype. The characterization of PoRV-A strains with unusual genotypes described in this study highlight the importance of surveys on the relationship between human and animal rotavirus strains.

Species H rotavirus detected in piglets with diarrhea, Brazil, 2012.

We determined nucleotide and deduced amino acid sequences of the rotavirus gene encoding viral protein 6 from 3 fecal samples collected from piglets with diarrhea in Brazil, 2012. The analyses showed that the porcine rotavirus strains in Brazil are closely related to the novel species H rotavirus.

Unusual outbreak of post-weaning porcine diarrhea caused by single and mixed infections of rotavirus groups A, B, C, and H.

Rotaviruses (RVs) are a major cause of severe diarrhea in humans and animals. Five of the nine RV groups (RVA, RVB, RVC, RVE, and RVH) have been previously detected in pigs; however, in pig herds worldwide, most studies highlight diarrhea outbreaks caused by RVA. In the present study, we describe detection and characterization of RV groups A, B, C, and H in fecal samples from pigs with single and mixed infections during a post-weaning diarrhea outbreak. The outbreak occurred in a single pig herd routinely vaccinated with an inactivated commercial vaccine for neonatal diarrhea control that included the RVA OSU (G5P[7]) strain. RVC (78%) was the most prevalent group found in single (34%) and mixed (44%) infections, followed by RVA (46%), RVB (32%), and RVH (18%). Phylogenetic analysis of three RVA strains allowed the characterization of two distinct G/P genotypes represented by G5P[13] and G9P[23], different from G5P[7] found in vaccines. Regardless of the RV group, mixed infections (54%) were more prevalent than single infections. Detection of RVB or RVH was associated with the presence of other RV groups, suggesting a secondary action of these RV groups in the reported outbreak. The detection of RV groups B, C, and H in the same pig herd suggests that these RVs act as causative agents of diarrhea and should be included in the diagnostic tests of porcine enteric diseases. These data provide new epidemiological information on RV diversity that need to be addressed in future studies for a better understanding and prevention of RV infections.

Diarrhea outbreaks in suckling piglets due to rotavirus group C single and mixed (rotavirus groups A and B) infections

Porcine group A rotavirus (PoRVA) is a major cause of neonatal diarrhea in suckling and recently weaned piglets worldwide. The involvement of non-group A rotavirus in cases of neonatal diarrhea in piglets are sporadic. In Brazil there are no reports of the porcine rotavirus group C (PoRVC) as etiologic agent of the diarrhea outbreaks in piglets. The aim of this study was to describe the identification of rotavirus group C in single and in mixed infection with rotavirus groups A and B in three neonatal diarrhea outbreaks in suckling (<21-day-old) piglets, with 70% to 80% and 20% to 25% of morbidity and lethality rates, respectively, in three pig herds located in the state of Santa Catarina, Brazil. The diagnosis of PoRV in the diarrheic fecal samples was performed using polyacrylamide gel electrophoresis (PAGE) to identify the presence of porcine rotavirus groups A, B (PoRVB), and C, and by RT-PCR (PoRVA and PoRVC) and semi-nested (SN)-PCR (PoRVB) to partially amplify the VP4 (VP8*)-VP7, NSP2, and VP6 genes of PoRVA, PoRVB, and PoRVC, respectively. One RT-PCR (PoRVA and PoRVC) and SN-PCR (PoRVB) product of each group of rotavirus of each diarrhea outbreak was submitted to nucleotide (nt) sequence analysis. Based on the PAGE technique, 4 (25%) and 1 (6.25%) of the 16 diarrheic fecal samples evaluated in the first outbreak presented PoRVA and PoRVC electropherotype, respectively, and 11 (68.75%) were negative. In the second outbreak, 3 (42.85%) of the 7 fecal samples evaluated presented PoRVA electropherotype, and in 3 (42.85%) and in 1 (14.3%) fecal samples were detected inconclusive and negative results, respectively. Three (30%) of the 10 fecal samples of the third outbreak presented PoRVC electropherotype; 5 (50%) and 2 (20%) samples showed negative and inconclusive results, respectively. Based on the RT-PCR and SN-PCR assays in the first neonatal diarrhea outbreak, PoRVC was detected in 13 (81.2%) of the 16 diarrheic fecal samples evaluated. PoRVC single infection was identified in 4 (25%) of these samples and mixed infections with PoRVA and PoRVB in 9 (56.2%) fecal samples. All of the seven diarrheic fecal samples evaluated from the second neonatal diarrhea outbreak were positive for PoRVC, whereas its mixed infection with other PoRV groups was detected in 4 (57.2%) samples. In the third outbreak, PoRVC in single infection was detected in all of the 10 diarrheic fecal samples analyzed. In the nt sequence analysis, the PoRVA strains of the first and second outbreaks demonstrated higher nt identity with G4P[6] and G9P[23] genotypes, respectively. The PoRVB strains (first and second outbreaks) and the PoRVC strains (first, second, and third outbreaks) showed higher nt identity and clustered in the phylogenetic tree with PoRVB and PoRVC strains that belong to the N4 and I1 genotypes, respectively. This is the first description in Brazil of the involvement of PoRVC in the etiology of diarrhea outbreaks in suckling piglets. The results of this study demonstrated that PoRVC, in both single and mixed infections, is an important enteropathogen involved in neonatal diarrhea outbreaks in piglets and that the use of more sensitive diagnostic techniques allows the identification of mixed infections involving two or even three groups of PoRV, which may be more common than previously reported.

Extra-intestinal detection of canine kobuvirus in a puppy from Southern Brazil

This study presents the pathological, immunohistochemical, and molecular findings associated with the extra-intestinal detection of canine kobuvirus (CaKV) in a 5-month-old Chihuahua puppy, that had a clinical history of bloody-tinged feces. Principal pathological findings were interstitial pneumonia, necrotizing bronchitis, and parvovirus-induced enteritis. Molecular diagnostic methods identified CaKV within the cerebellum, cerebrum, lung, tonsil, and liver. CaKV and rotavirus were not identified within the feces and intestine. Immunohistochemistry (IHC) assays detected antigens of CDV and CAdV-1 in the lungs. These results confirmed the extra-intestinal detection of CaKV in this puppy and represent the first extra-intestinal detection of CaKV in a dog.

The evaluation of enteric viruses in asymptomatic free-ranging non-human primates (Alouatta guariba clamitans, Alouatta caraya, Callithrix spp., Callithrix penicillata, and Leontopithecus caissara) in southern Brazil

This study evaluated the presence of rotavirus groups A, B, and C (RV‐A, RV‐B, and RV‐C), sapovirus (SaV), and norovirus (NoV) in asymptomatic non‐human primates (NHP).

Isolation of an unusual G26P[13] group A rotavirus strain from piglets with diarrhea in Brazil

This report describes the identification of an unusual G26P[13] genotype combination in a porcine group A rotavirus (RVA) strain. In a retrospective study, the VP7 (G type) and VP4 (P type) genes of porcine RVA Brazilian field strains identified in two diarrheic suckling piglets were amplified by RT-PCR and subjected to sequencing. The sequence analysis revealed the G26P[13] RVA genotype in one strain (BRA381) and G26P[X] in the other (BRA382). This study presents evidence of porcine RVA G26 genotype circulating in a Brazilian pig herd.