Experimental infection of calves with an adenovirus isolated from sheep and related to bovine Adenovirus type 2 I. Clinical and virological studies

Detection of known and novel adenoviruses in cattle wastes via broad-spectrum primers

The critical assessment of bovine adenoviruses (BAdV) as indicators of environmental fecal contamination requires improved knowledge of their prevalence, shedding dynamics, and genetic diversity. We examined DNA extracted from bovine and other animal waste samples collected in Wisconsin for atadenoviruses and mastadenoviruses using novel, broad-spectrum PCR primer sets. BAdV were detected in 13% of cattle fecal samples, 90% of cattle urine samples, and 100% of cattle manure samples; 44 percent of BAdV-positive samples contained both Atadenovirus and Mastadenovirus DNA. Additionally, BAdV were detected in soil, runoff water from a cattle feedlot, and residential well water. Overall, we detected 8 of 11 prototype BAdV, plus bovine, rabbit, and porcine mastadenoviruses that diverged significantly from previously reported genotypes. The prevalence of BAdV shedding by cattle supports targeting AdV broadly as indicators of the presence of fecal contamination in aqueous environments. Conversely, several factors complicate the use of AdV for fecal source attribution. Animal AdV infecting a given livestock host were not monophyletic, recombination among livestock mastadenoviruses was detected, and the genetic diversity of animal AdV is still underreported. These caveats highlight the need for continuing genetic surveillance for animal AdV and for supporting data when BAdV detection is invoked for fecal source attribution in environmental samples. To our knowledge, this is the first study to report natural BAdV excretion in urine, BAdV detection in groundwater, and recombination in AdV of livestock origin.

The detection of an unidentified type of adenovirus in the stools of calves with weak calf syndrome by use of a commercial kit designed for the detection of human adenoviruses

An outbreak of polyarthritis in newborn calves in a large collective dairy herd was characterized by intra‐articular blood‐tinged synoviae, blood tainted faeces and massive subcorneal haemorrhages. Faecal samples from eight clinical newborn cases, 10 from unrelated dairy farms and 10 faecal samples from healthy calves were examined by the Rida^® Quick rotavirus/adenovirus‐combi test . A specific adenovirus antigen precipitin‐line was seen in the reaction in all the faecal samples from the diseased calves (n = 8), while all the others (n = 20) were negative. In addition, the same positive reaction was noted when one aqueous humor and two synovial samples were tested with this kit. Several other enteropathogens were found sporadically, but no conclusive significance could be attributed to their presence. Bovine viral diarrhoea and infectious bovine rhinothracheitis viruses as well as Chlamydia spp. and Mycoplasma spp. were not involved in this episode.

Subtypes of bovine adenovirus type 2 exhibit major differences in region E3

The genomes of two adenovirus type 2 strains which were isolated from different hosts have been investigated. One of these strains designated ORT-111 was originally isolated from a lamb in Hungary during an outbreak of pneumoenteritis. This isolate was typed as bovine adenovirus type 2 (Ad bos 2) in a neutralization assay. The genome of ORT-111 was compared to that of the prototype strain of Ad bos 2, a virus which exclusively has been isolated from cattle. Electron microscopic heteroduplex analysis showed that 95% of the genomes were well matched, forming stable duplexes at Tm -6 degrees. Two distinct substitution loops were, however, seen which were approximately 0.5 and 1.0 kbp long. The centers of the two loops were located 5.3 and 7.7 kbp from one end of the Ad bos 2 genome. In order to map these regions relative to the gene map of human adenovirus type 2 (Ad2), restriction enzyme cleavage fragments of the two bovine viruses were cloned and hybridized to different sets of restriction fragments of human Ad2. From these results it was apparent that the centers of the two substitution loops were located at coordinates 76 and 83, respectively; thus at positions which fall within region E3 and the adjacent gene for polypeptide VIII of human Ad2. The observed differences between the genomes of the two Ad bos 2 strains are in sharp contrast to those previously observed when the genomes of different human adenovirus serotypes were compared. In the latter case the hexon and the fiber genes showed the most pronounced variation.

DNA structure, and hemagglutination properties of bovine adenovirus type 2 strains which bypass species specificity

Bovine adenovirus type 2 (Ad bos 2) strains were examined which had been isolated during natural outbreaks among calves, and lambs in Hungary [Belák, S., Pálfi, V.: Arch. ges. Virusforsch. 46,366-369 (1974)]. Differences were detected in hemagglutination properties, and in the restriction site maps of the DNA, which seem to be sufficient to group isolates of Ad bos 2 into two subtypes (subspecies). Some of the strains, recovered from cattle including prototype strain No. 19 are suggested to be separated as subtype A. These viruses hemagglutinate bovine red blood cells, and the physical map of the DNA is similar to, or identical with that of the prototype strain. Virus strains tentatively grouped into subtype B are pathogenic for both cattle, and sheep under natural conditions. Members of subtype B hemagglutinate only rat erythrocytes, and characteristic differences may be detected with BamHI, EcoRI, KpnI, and SalI restriction endonucleases in comparison to the physical maps of the DNA of prototype virus. The genome size of all isolates tested was measured to be of Mr 19.5 to 20.0 X 10(6), similar to Ad ovi 1, 4, and Ad bos 4, and 6. All isolates of subtype B characteristics were shown to encapsidate heterogeneous genome populations which could be distinguished from those of subtype A by the presence of specific restriction endonuclease cleavage fragments with molar ratios of less than 1.0.