Detection of adenovirus hexon sequence in a cat by polymerase chain reaction (short communication)

Feline Adenovirus Isolate Shows Silent Nucleotide Alterations, Alternative Receptor/Coreceptor Binding, High Resistance to Disinfectants and Antiviral Drugs, as Well as Immunomodulation

Adenovirus (AdV) infection has been rarely documented in cats and other felids. Partial sequences of the hexon and fiber genes of a Hungarian feline adenovirus isolate (FeAdV isolate) showed a close relationship to human AdV (HAdV) type C1. Further molecular and biological characterization is reported here. Whole-genome sequencing revealed two silent mutations in the genome of the FeAdV isolate compared to a HAdV-C1 reference strain (at positions 14,096 and 15,082). Competitive antibody binding to the Coxsackie-adenovirus receptor and αvβ3 and αvβ5 integrin coreceptors inhibited the binding of the FeAdV isolate in different cell lines, but residual infections suggested alternative entry routes. The FeAdV isolate was found to be more sensitive to heat, low pH and detergents, but more resistant to alkaline and free chlorine treatments, as well as to ribavirin, stavudine and cidofovir treatments, than other human AdV types. We observed a suppression of IL-10 and TGF-β1 production during the entire course of viral replication. This immunomodulation may restore intratumoral immunity; thus, the FeAdV isolate could serve as an alternative oncolytic vector. Collectively, our results support that the Hungarian FeAdV isolate is a variant of common HAdV-C1. The cohabitation of cats with humans might result in reverse zoonotic infection. Felids appear to be susceptible to persistent and productive adenovirus infection, but further studies are needed to better understand the clinical and epidemiological implications.

Adenovirus surveillance in wild carnivores from Brazil

Landscape transformation favors the spread of new pathogens that can be shared between domestic and wild animals. Certain adenoviruses (e.g., canine adenovirus 1 and 2, family Adenoviridae) can infect domestic and wild carnivores. In domestic canids, these viruses are associated with hepatic and respiratory diseases (among others). Nevertheless, information regarding adenovirus pathogenicity and molecular features in wild carnivores is still limited. Herein we surveyed adenovirus in free-ranging carnivores from Brazil. Total DNA was extracted from and subsequently tested by a nested panPCR in spleen and/or lung of 52 carnivores, representing species of the following families: Canidae (n = 4), Felidae (n = 3), Mustelidae (n = 2) and Procyonidae (n = 2). The obtained sequences were compared to others available at GenBank. Available tissue samples from the positive cases were evaluated histopathologically. One out of 52 (1.9%, CI 95%, 0.0-5.7%) carnivores was positive; a roadkilled ocelot (Leopardus pardalis). The obtained sequence presented a low deduced amino acid (78.1%) similarity with the closest adenovirus, identified in a pinniped from the United States of America. This fact and its detection in a novel host suggest it may be representative of a novel species and denominated ocelot adenovirus 1. None of the gross and microscopic findings of the positive case were associated with adenovirus. To the authors' knowledge, this is the first report of adenovirus in wild felids of South America and the second worldwide. Further studies are necessary to assess the epidemiology and potential pathogenicity of this agent in wild carnivores.

Adenovirus Isolated From a Cat Is Related to Human Adenovirus 1

An adenovirus (AdV) has been isolated from the rectal swab of a domestic cat (Felis catus) and named feline adenovirus (FeAdV) isolate. It replicates and causes cytopathological effects in many human, feline, other mammalian cell lines that have both Coxsackie-adenovirus-receptor and integrins. Its antigens cross-react with anti-human adenovirus antibodies in immunofluorescence and immunocytochemistry assays. Electron microscopy revealed typical extracellular icosahedral particles and pseudo arrays inside cells. Sequence analysis of hexon and fiber genes indicates that this virus might belong to human adenovirus (HAdV) C species and might be a variant of type 1. In the fiber protein, three altered amino acids occur in the shaft; four altered residues are found in the knob region as compared to a European HAdV might be type 1 isolate (strain 1038, D11). One alteration affects amino acid 442 forming an RGS motif in an alanine rich region that might be an alternative way to bind integrins with subsequent internalization. Substitutions in the hexon sequence are silent. As compared to published HAdV sequences, the fiber is related to the original American prototype and recently described Taiwanese HAdV 1 isolates, but the hexon sequences are related to adenovirus isolates from France, Germany, Japan, and Taiwan. Serology carried out on FeAdV infected M426 cells indicates a prevalence of IgG in 80% of domestic cats in Delaware, United States. FeAdV isolate seems to be a recently recognized virus with possible pathogenic effects and, simultaneous human and feline infections are possible. Further molecular and biological characterization of this feline adenovirus isolate, as well as studies on both human and feline epidemiology and pathomechanisms, especially in endangered big cats, are warranted. FeAdV might have further practical advantages. Namely, it could be utilized in both human and feline AIDS research, developed into diagnostic tools, and gene therapy vectors in the near future.

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.

Lack of evidence of avian adenovirus infection among turkey workers

Zoonotic infections constitute a major public health concern. Outbreaks of the SARS (severe acute respiratory syndrome) and avian influenza viruses are but recent examples. Although there are many animal-specific adenoviruses and occasionally they have been noted to infect man, rarely have they been studied as potential zoonotic pathogens. In this study, the authors hypothesized that the hemorrhagic enteritis virus (HEV), an avian adenovirus that causes illness among turkeys, might infect humans. Using an enzyme immunosorbent assay, the authors compared sera from 95 turkey-exposed individuals with sera from 82 nonexposed controls for serologic evidence of infection with HEV. Multivariate modeling revealed no statistical difference in elevated antibody titers against HEV between the two groups. These data do not support the hypothesis that avian adenoviruses cross the species barrier to infect humans.