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.
Inclusion body hepatitis caused by Aviadenovirus in a tropical screech owl (Megascops choliba)
In 2016, tropical screech owl (Megascops choliba) (Tso) chicks were suddenly found dead in a Japanese breeding facility. We autopsied a 9-day-old Tso and discovered white spots scattered on the liver surface. Multifocal necrosis was diffused, and macrophages had infiltrated the necrotic hepatic lesions. Hepatocytes contained numerous intranuclear inclusion bodies. Immunohistochemical staining detected Adenovirus antigen only in the liver. Next, PCR and sequencing (LC536616) identified Tso Adenovirus (TsoAd). Basic Local Alignment Search Tool (BLAST) and phylogenic analyzes suggested TsoAd is an owl Aviadenovirus. Our study contributes to an improved understanding of infectious disease among captive raptors.
The infection process, sporulation and survival of Alternaria helianthi on sunflower
SUMMARY 
 
Electron microscopy was used to study the infection of sunflower leaves by Alternaria helianthi. Conidia germinated by producing one to many germ tubes which grew across the leaf surface before forming appressoria. The fungus directly penetrated its host through the cuticle and epidermis. Entry into the host through wounds and stomates was also observed. Extracellular sheaths were found to be associated with germ tubes and intercellular hyphae of A. helianthi. Conidiophores developed through collapsed stomates, from leaf veins, trichomes and also from mycelium growing across the host leaf surface. Microcylic conidia were produced directly from parent conidia under certain conditions. Studies using a volumetric spore trap showed that the airborne spore concentration followed a distinct periodicity with peaks occurring between 0900 and 1100 h each day. Laboratory studies showed that safflower, noogoora burr and bathurst burr could serve as alternative hosts for A. helianthi. The pathogen was readily isolated from sunflower crop debris from a diseased crop that had been harvested 1 yr earlier.