Persistent goose hemorrhagic polyomavirus infection on a Belgian goose farm

Goose hemorrhagic polyomavirus (GHPV) is the causative agent of hemorrhagic nephritis enteritis of geese (HNEG), one of the major diseases of domestic geese in Europe. This case report describes a persistent outbreak of a GHPV infection on a Belgian goose farm. Clinical symptoms, necropsy lesions, and histopathologic lesions observed were compatible with previous reports of HNEG outbreaks. PCR analysis confirmed the diagnosis of GHPV. To our knowledge, this is the first report of an outbreak of a GHPV infection on a Belgian goose farm. This is evidence that GHPV is not only present in countries known for extensive waterfowl production, but disease outbreaks also occur in countries with less extensive goose production

Growth regulation in amphibian pathogenic chytrid fungi by the quorum sensing metabolite tryptophol

Amphibians face many threats leading to declines and extinctions, but the chytrid fungal skin pathogens Batrachochytriurn dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) have been identified as the causative factors leading to one of the greatest disease-driven losses of amphibian biodiversity worldwide. Infection may lead to different clinical outcomes, and lethal infections are commonly associated with unrestricted, exponential fungal growth in the amphibian epidermis. Mechanisms underpinning Bd and Bsal growth in the amphibian host are poorly understood. Here, we describe a quorum sensing mechanism that allows cell-to-cell communication by Bd and Bsal in order to regulate fungal densities and infection strategies. Addition of chytrid culture supernatant to chytrid cultures resulted in a concentration-dependent growth reduction and using dialysis, small metabolites were shown to be the causative factor. U-HPLC-MS/MS and in vitro growth tests identified the aromatic alcohol tryptophol as a key metabolite in regulating fungal growth. We determined tryptophol kinetics in both Bd and Bsal and confirmed the autostimulatory mode of action of this quorum sensing metabolite. Finally, we linked expression of genes that might be involved in tryptophol production, with in vitro and in vivo chytrid growth. Our results show that Bd and Bsal fungi use tryptophol to act as multicellular entities in order to regulate their growth

The role of SHDA in faecal shedding of Salmonella typhimurium in pigs

Prolonged faecal shedding of Salmonella in pigs contributes to contamination of carcasses. The shdA gene has been characterized as an important locus for persistency of Salmonella Typhimurium in mice. The aim of this study was to assess the contribution of ShdA in faecal shedding of S. Typhimurium in pigs. Pigs were orally inoculated with a S. Typhimurium strain or its isogenic shdA mutant strain. For the first few days after inoculation, the shdA mutant strain was more virulent than the wild type strain, as indicated by higher excretion levels, more pronounced diarrhea and higher numbers of infected organs. No effect on long-term shedding was found. Increased in vitro invasion levels of the shdA mutant strain were noticed in intestinal epithelial cells. In conclusion, a shdA mutant strain of S. Typhimurium is more virulent during the first days after inoculation and is not impaired in persistency or prolonged shedding in pigs

Co-occurrence of Mycoplasma species and pigeon herpesvirus-1 infection in racing pigeons (Columba livia)

Oropharyngeal swab samples were collected from 438 live racing pigeons (Columba livia), with and without signs of respiratory disease, that were housed in 220 lofts in 3 provinces in the western part of the Netherlands. Polymerase chain reaction (PCR) was used to identify Mycoplasma species and pigeon herpesvirus-1 (PHV-1) from the samples. In 8.6% of the pigeon lofts tested, signs of respiratory disease were present in pigeons at sampling, and in 30.9% of the sampled pigeon lofts, respiratory signs were observed in pigeons during the 6-month period immediately before sampling. A total of 39.8% of tested pigeons (54.5% of tested lofts) were positive for Mycoplasma species, and 30.6% of tested pigeons (48.6% of tested lofts) were positive for PHV-1. In 15.8% of the tested pigeons (26.8% of tested pigeon lofts), coinfection by Mycoplasma species and PHV-1 was identified. The number of pigeon lofts having pigeons coinfected by Mycoplasma species and PHV-1 was higher than that where only one of the infections was identified. Neither the presence of Mycoplasma species, PHV-1, nor the co-occurrence of both infections was significantly associated with signs of respiratory disease

Racing pigeons : a reservoir for nitro-imidazole-resistant Trichomonas gallinae

Trichomonas gallinae, the cause of avian trichomonosis, is most commonly found in the order Columbiformes. Racing pigeons are often treated preventively with nitro-imidazoles which could result in the emergence of resistant isolates, and these isolates can be a treath to wildlife when exchanges occur. The sequence type of 16 T. gallinae isolates obtained from racing pigeons and 15 isolates from wild pigeons was determined based on the ITS1/5.8S rRNA/ITS2 region sequence. In addition, the resistance profiles of these isolates against five different nitro-imidazoles (metronidazole, dimetridazole, ronidazole, tinidazole and carnidazole) were determined. Two different Trichomonas sequence types were isolated. Sequence type A isolates were recovered from racing and wild pigeons, in contrast to sequence type B which was only isolated from wild pigeons. Isolates with sequence type B were all susceptible to the tested nitro-imidazoles, except for tinidazole-resistance in 3 isolates. Resistance to the nitro-imidazoles was observed more frequently in isolates obtained from racing pigeons than from wild pigeons, with most isolates belonging to sequence type A. A higher percentage of the sequence type A isolated from racing pigeons, in comparison with those isolated from the wild pigeons, were resistant to the nitro-imidazoles and displayed higher mean lethal concentration (MLC) values. Two isolates belonging to sequence type A, 1 recovered from a racing pigeon and 1 from a wild pigeon, displayed a similar resistance pattern, suggesting a potential exchange of resistant isolates between racing pigeons and wild pigeons