Viruses isolated from sheep

Ovine adenoviruses infecting sheep and goats in Türkiye: detection and molecular characterization of three different types

Adenoviruses (AdVs) have been detected in a wide variety of animals. To date, eight types of AdVs in sheep and two types in goats have been identified, which belong to two distinct genera, Mastadenovirus and Atadenovirus. Typically, the term pneumo-enteritis is used to describe adenovirus-induced disease in small ruminants, which has been associated with both enteric and respiratory symptoms of varying severity. The aim of this study was to detect and identify AdVs of small ruminants belonging to the genera Mastadenovirus and Atadenovirus. For this purpose, diagnostic samples (47 lung, 27 intestine, and two pooled tissue samples including intestine and lung) from 49 small ruminants (39 sheep and 10 goats) were used. Following the viral DNA extraction, PCR was carried out by using the primers targeting the hexon gene in order to detect both mast- and atadenoviruses. Sequencing the amplified fragments revealed the presence of three types of ovine adenovirus (OAdV): OAdV-3, OAdV-4, and OAdV-8. Specifically, OAdV-3 was detected in two sheep and a goat while OAdV-4 and OAdV-8 were found in only one sheep each. There is still limited data on the interaction between the viruses in different adenovirus genera and the detected disease, as well as the genetic diversity of adenoviruses, especially in small ruminants. In conclusion, the detection of AdVs in lung and intestinal tissues of small ruminants in this study suggests that these viruses may have contributed to the disease and/or predisposed to other agents.

No Exchange of Picornaviruses in Vietnam between Humans and Animals in a High-Risk Cohort with Close Contact despite High Prevalence and Diversity

Hospital-based and community-based 'high-risk cohort' studies investigating humans at risk of zoonotic infection due to occupational or residential exposure to animals were conducted in Vietnam, with diverse viruses identified from faecal samples collected from humans, domestic and wild animals. In this study, we focus on the positive-sense RNA virus family Picornaviridae, investigating the prevalence, diversity, and potential for cross-species transmission. Through metagenomic sequencing, we found picornavirus contigs in 23% of samples, belonging to 15 picornavirus genera. Prevalence was highest in bats (67%) while diversity was highest in rats (nine genera). In addition, 22% of the contigs were derived from novel viruses: Twelve phylogenetically distinct clusters were observed in rats of which seven belong to novel species or types in the genera Hunnivirus, Parechovirus, Cardiovirus, Mosavirus and Mupivirus; four distinct clusters were found in bats, belonging to one novel parechovirus species and one related to an unclassified picornavirus. There was no evidence for zoonotic transmission in our data. Our study provides an improved knowledge of the diversity and prevalence of picornaviruses, including a variety of novel picornaviruses in rats and bats. We highlight the importance of monitoring the human-animal interface for possible spill-over events.

Serologic and hexon phylogenetic analysis of ruminant adenoviruses

The objectives of this study were to determine the antigenic relationship among ruminant adenoviruses and determine their phylogenetic relationship based on the deduced hexon gene amino acid sequence. Results of reciprocal cross-neutralization tests demonstrated antigenic relationships in either one or both directions among bovine adenovirus type 6 (BAdV-6), BAdV-7, ovine adenovirus type 7 (OAdV-7), caprine adenovirus type 1 (GAdV-1), and deer adenovirus (Odocoileus adenovirus 1, OdAdV-1). No antigenic cross-reactivity was observed among BAdV-1 through -5, and -8 and the other putative ruminant adenoviruses. Two PCR primer sets, one for mastadenovirus and atadenovirus that amplified an approximately 2,700-bp region in the hexon genes were used for comparative studies. Phylogenetic analysis of the deduced hexon amino acid sequences clustered the ruminant adenoviruses on the Mastadenovirus and Atadenovirus genus branches of the Adenoviridae tree. The recent classification of BAdV-6, and -7 as members of the genus Atadenovirus was supported by phylogenetic distance matrix analysis of their deduced hexon amino acid sequences. Further, we propose that BAdV-6 and -7 be recognized as members of new Atadenovirus species, Bovine adenovirus E and Bovine adenovirus F, respectively. Phylogenetic analysis of OdAdV-1 places this virus in the genus Atadenovirus with a proposed new species Odocoileus adenovirus A. OAdV-6 and GAdV-2 are proposed as members of new Mastadenovirus species Ovine adenovirus C and Goat adenovirus A, respectively.

DNA sequencing and phylogenetic analysis of the protease gene of ovine adenovirus 3 suggest that adenoviruses of sheep belong to two different genera

Until now, the only published ovine adenovirus DNA sequence was the complete genome of ovine adenovirus isolate 287 (OAV287) which, compared to other mammalian adenoviruses, possesses strikingly unique genomic organisation and should properly be classified into a new adenovirus genus. The protease gene sequence of ovine adenovirus type 3 (OAdV-3) was determined and analysed. The results of phylogenetic analysis of the 205 residue long protein demonstrated that OAdV-3 belongs to the genus Mastadenovirus, and is surprisingly closely related to bovine adenovirus type 2. In spite of the common host origin, the evolutionary distance between OAdV-3 and OAV287 proved to be great suggesting that sheep, similarly to cattle and fowl, might be infected by distantly related adenoviruses belonging to different genera.

Studies on the antigenic relationship between bovine subgroup 2 and conventional mammalian adenoviruses using immunofluorescence

In double immunodiffusion tests between a bovine subgroup 2 adenovirus (serotype 8) and other mammalian adenoviruses, no group-specific crossing was demonstrated. However, in cross-fluorescent antibody tests (FAT) between bovine subgroup 2 viruses (serotypes 5, 7 and 8) and conventional (non-subgroup 2) adenoviruses from several species (bovine adenovirus serotypes 1 and 2, ovine serotypes 1, 4 and 5, porcine serotype 1, and human serotypes 2 and 5) sharing of antigens was demonstrated. The FAT titres observed when rabbit antisera to conventional adenoviruses were used to stain bovine subgroup 2 viruses were, however, much lower than titres with other non-subgroup 2 viruses. The converse was also true. The crossing was also predominantly one-sided. The low level cross was confirmed using antisera to selected viruses prepared in chickens to exclude interference by possible natural adenovirus infections in the rabbits used to prepare the antisera in the initial experiments.

A sixth species of ovine adenovirus isolated from lambs in New Zealand

Two adenoviruses (WV419/75 and WV757/75), isolated from lambs in New Zealand were compared using neutralisation tests with the five recognised ovine adenovirus species, NINE bovine and four porcine adenoviruses. WV419/75 did not cross-react with any of the viruses tested and represents a new ovine adenovirus species (OAV-6). WV757/75 cross-reacted with bovine adenovirus type 7 (BAV-7) with a homologous to heterologous titre ratio of 16 in one direction only, and also showed a substantial one-way cross reaction in haemagglutination-inhibition tests (WV757 antiserum inhibiting haemagglutination by BAV-7). There was therefore insufficient distinction from BAV-7 virus to allow designation as a separate species. Fluorescent antibody studies with WV419 and WV757 demonstrated virus inclusions in the nuclei of infected cells. These were stained by antiserum to OAV-4 indicating presence of the mammalian group antigen. Thin section electron microscope studies showed typical adenovirus particles and associated inclusions in cell nuclei. The similarity of the two viruses to the bovine subgroup 2 adenoviruses in several of their properties is discussed.

Reovirus-like agent (rotavirus) from lambs

Rotavirus particles were demonstrated by electron microscopy in the feces of lambs with diarrhea. Rotavirus antigen was synthesized in cell cultures infected with filtrates of the diarrheic feces, but the virus was not adapted to grow serially in cell cultures. An antigenic relationship between rotaviruses from lambs, pigs, and calves was demonstrated by immunofluorescence. Colostrum-deprived lambs were infected with the lamb rotavirus, and the virus was passaged in lambs. Viral replication occurred in the villous epithelial cells of the small intestine, and the virus was excreted in the feces up to 78 h postinfection. Diarrhea was not observed in the experimentally infected lambs.

Immunoperoxidase stain of measles antigen in tissue culture

A specific electron microscopy staining technique for measles antigen has been developed by using Vero cells infected with a subacute sclerosing panencephalitis (SSPE) measles virus strain and fixed in glutaraldehyde or formaldehyde. Peroxidase-labeled antibody was prepared according to the method of Avrameas (4). Sera from SSPE patients with high measles antibody titer as well as normal human sera with and without measles antibody were used. With both fixatives, specific labeling was obtained on the surface of infected cells, on the budding site, and on complete viral particles. The cell membrane staining sometimes had a patchy distribution in that the reaction was most intense on the surface projections in front of each nucleocapsid. This suggests modification of the cell membrane in association with the nucleocapsids. In contrast, no label was detected on the membranes of the cells during the latent period from penetration through maturation of the virus. In formaldehyde-fixed cultures, cytoplasmic inclusions were stained, and this label was located on the "fuzzy" material around the nucleocapsids. The smooth type of nucleocapsids, mainly seen in the nucleus, were never labeled. These findings suggest that the antigenic nature of the "fuzzy" nucleocapsids in the cytoplasm may be different from that of the "smooth" nucleocapsids. The immunoperoxidase method gives good resolution of viral antigenic sites at high magnifications under electron microscopy and may be of value in studies on the immunopathogenesis of SSPE and other chronic viral infections.