Molecular characterization of fowl aviadenoviruses species D and E associated with inclusion body hepatitis in chickens and falcons indicates possible cross-species transmission
ABSTRACT During the period from 2015 to 2017, frequent outbreaks of inclusion body hepatitis (IBH) were observed in broiler chickens and falcons in Saudi Arabia. Fifty samples were collected from both species. The histopathological examination and polymerase chain reaction confirmed the IBH infection in eight samples (five samples from chickens and three samples from falcons). The genomic sequence and phylogenetic analysis based on nucleotide and amino acid sequences of Saudi strains, reference fowl aviadenoviruses (FAdVs) and field viruses available in Genbank revealed that all investigated FAdVs clustered into FAdV-2 (species D) and FAdV-6 (species E). The host-dependent characterization revealed that falcon origin strains showed low identity (∼35%) with falcon adenoviruses isolated from USA, which clustered into a separate group. The identification of FAdV-D and FAdV-E in diseased falcons and chickens indicates cross-species transmission although falcons and chickens are phylogenetically different. The control of IBH infection in falcons and chickens should be based on the separation of carriers and susceptible chickens as well as falcons to prevent cross-species contact. Vaccination is an important method for prevention of IBH. The characterization of newly emerging FAdV strains provides valuable information for the development of an efficacious control strategy based on the molecular structure of current circulating FAdV strains in different species of birds.
A survey of a mixed species aviary provides new insights into the pathogenicity, diversity, evolution, host range, and distribution of psittacine and passerine adenoviruses
ABSTRACT A Bourke’s parrot (Neopsephotus bourkii) originating from an aviary in Australia, containing two species of parrots, five species of finch and a species of dove, was presented for necropsy. The Bourke’s parrot died from gastritis caused by Macrorhabdus ornithogaster, but also had an interstitial nephritis and ureteritis with adenovirus-like inclusion bodies within collecting duct epithelial cells. The adenovirus causing the lesions was shown to be Psittacine adenovirus-2 (PsAdV-2) using a PCR assay specific for adenoviruses and sequencing of amplicons. A survey of droppings from other birds in the aviary using the same PCR assay with amplicon sequencing found a high prevalence of infection of PsAdV-2 in Bourke's and scarlet-chested parrots (Neophema splendida). PsAdV-2 was also present in droppings from a Namaqua dove (Oena capensis). Gouldian finches (Erythrura gouldiae), red-billed firefinches (Lagonosticta senegala), and red-throated parrot finches (Erythrura psittacea) were shedding Gouldian finch adenovirus-1 (GFAdV-1). Two novel adenoviruses, an atadenovirus and a siadenovirus, were detected in the droppings from long-tailed finches (Poephila acuticauda). Kidney tissue from three of four scarlet-chested parrots submitted for necropsy from a second aviary were also positive for PsAdv-2. These findings and previously reported findings of widespread PsAdv-2 infection in captive orange-bellied parrots (Neophemia chrysogaster) raise the possibility that PsAdV-2 is enzootic in Australian aviculture. This represents the first report of GFAdV-1 in Australia and first identification of infection in finch species other than the Gouldian finch. Identification of two novel adenoviruses in long-tailed finches suggests that other novel adenoviruses are circulating in other finch species. RESEARCH HIGHLIGHTS Psittacine adenovirus-2 was present in high prevalence in two Australian aviaries. Gouldian finch adenovirus-1 (GFAdV-1) was detected in Australia for the first time. The host range of GFAdV-1 host range was expanded to other finch species. Novel atadenovirus and siadenovirus were detected in Estrildid finches.
Characterization of Aqueous Dispersions and Gels Made of Sodium Caseinate and Basil Seed Gum: Phase Behavior, Rheology, and Microstructure
The interactions between sodium caseinate (NaCas) and basil seed gum (BSG) in the presence of calcium chloride (CaCl 2 ) were investigated. The phase behavior of the mixed aqueous dispersions and their gels revealed a homogeneous mixture, obtained at the higher concentrations of both CaCl 2 and BSG. The Herschel-Bulkley model sufficiently fitted the flow behavior of the mixture solution data. Apparent viscosity increased significantly ( p  < 0.05) by increasing the concentration of BSG, where the addition of CaCl 2 had no significant effect on the viscosity of the samples ( p  > 0.05). Furthermore, there was an increase in thixotropy due to the higher concentrations of BSG and CaCl 2 . Based on the frequency sweep test, at the low frequencies, a more gel-like behavior was observed in the case of the higher concentrations of either BSG or CaCl 2 . The rheological and SEM data suggested that the stronger structure of NaCas-BSG gel in the presence of the higher concentrations of CaCl 2 was related to the induction of complex formation between the two biopolymers.