First Observation of Leptospira interrogans in the Lungs of Rattus norvegicus.

We report the first two cases of pulmonary presence of leptospires in apparently healthy rats captured in a city park in Lyon (France). Only renal carriage of Leptospira has been described in the literature. Blood serology was performed in parallel with molecular and histological analyses of the kidney and lung samples. We isolated leptospires from the kidneys of two out of three seropositive wild rats. These results were confirmed by specific detection of pathogenic Leptospira by real-time PCR. Moreover, Leptospira DNA was detected in lung tissues. Immunohistochemistry and Warthin-Starry staining revealed that leptospires were present on the surface of the ciliated epithelium of the bronchi. Using PCR of the rrs (16S) gene and Multispacer Sequence Typing, DNA extracts of the kidney and lung were identified as belonging to Leptospira interrogans serovar Icterohaemorrhagiae "CHU Réunion." This first observation of the presence Leptospira in the lung with simultaneous renal carriage will require further study in future on several target organs to gain a better understanding of the Leptospira infection in wild rat.

Comparison of Mucosal, Subcutaneous and Intraperitoneal Routes of Rat Leptospira Infection.

Leptospirosis is a zoonosis found worldwide that is caused by a spirochete. The main reservoirs of Leptospira, which presents an asymptomatic infection, are wild rodents, including the brown rat (Rattus norvegicus). Experimental studies of the mechanisms of its renal colonization in rats have previously used an intraperitoneal inoculation route. However, knowledge of rat-rat transmission requires the use of a natural route of inoculation, such as a mucosal or subcutaneous route. We investigated for the first time the effects of subcutaneous and mucosal inoculation routes compared to the reference intraperitoneal route during Leptospira infection in adult rats. Infection characteristics were studied using Leptospira renal isolation, serology, and molecular and histological analyses. Leptospira infection was asymptomatic using each inoculation route, and caused similar antibody production regardless of renal colonization. The observed renal colonization rates were 8 out of 8 rats, 5 out of 8 rats and 1 out of 8 rats for the intraperitoneal, mucosal and subcutaneous inoculation routes, respectively. Thus, among the natural infection routes studied, mucosal inoculation was more efficient for renal colonization associated with urinary excretion than the subcutaneous route and induced a slower-progressing infection than the intraperitoneal route. These results can facilitate understanding of the infection modalities in rats, unlike the epidemiological studies conducted in wild rats. Future studies of other natural inoculation routes in rat models will increase our knowledge of rat-rat disease transmission and allow the investigation of infection kinetics.

Ultrasonographic characteristics of the abdominal esophagus and cardia in dogs.

Differential diagnoses for regurgitation and vomiting in dogs include diseases of the gastroesophageal junction. The purpose of this cross-sectional study was to describe ultrasonographic characteristics of the abdominal esophagus and gastric cardia in normal dogs and dogs with clinical disease involving this region. A total of 126 dogs with no clinical signs of gastrointestinal disease and six dogs with clinical diseases involving the gastroesophageal junction were included. For seven euthanized dogs, ultrasonographic features were also compared with gross pathology and histopathology. Cardial and abdominal esophageal wall thicknesses were measured ultrasonographically for all normal dogs and effects of weight, sex, age, and stomach filling were tested. Five layers could be identified in normal esophageal and cardial walls. The inner esophageal layer was echogenic, corresponding to the cornified mucosa and glandular portion of the submucosa. The cardia was characterized by a thick muscularis, and a transitional zone between echogenic esophageal and hypoechoic gastric mucosal layers. Mean (±SD) cardial wall thicknesses for normal dogs were 7.6 mm (±1.6), 9.7 mm (±1.8), 10.8 mm (±1.6), 13.3 mm (±2.5) for dogs in the <10 kg, 10-19.9 kg, 20-29.9 kg and ≥30 kg weight groups, respectively. Mean (±SD) esophageal wall thicknesses were: 4.1 mm (±0.6), 5.1 mm (±1.3), 5.6 mm (±1), and 6.4 mm (±1.1) for the same weight groups, respectively. Measurements of wall thickness were significantly correlated with dog weight group. Ultrasonography assisted diagnosis in all six clinically affected dogs. Findings supported the use of transabdominal ultrasonography as a diagnostic test for dogs with suspected gastroesophageal disease.

The Nocardia cyriacigeorgica GUH-2 genome shows ongoing adaptation of an environmental Actinobacteria to a pathogen's lifestyle.

BACKGROUND: Nocardia cyriacigeorgica is recognized as one of the most prevalent etiological agents of human nocardiosis. Human exposure to these Actinobacteria stems from direct contact with contaminated environmental matrices. The full genome sequence of N. cyriacigeorgica strain GUH-2 was studied to infer major trends in its evolution, including the acquisition of novel genetic elements that could explain its ability to thrive in multiple habitats. RESULTS: N. cyriacigeorgica strain GUH-2 genome size is 6.19 Mb-long, 82.7% of its CDS have homologs in at least another actinobacterial genome, and 74.5% of these are found in N. farcinica. Among N. cyriacigeorgica specific CDS, some are likely implicated in niche specialization such as those involved in denitrification and RuBisCO production, and are found in regions of genomic plasticity (RGP). Overall, 22 RGP were identified in this genome, representing 11.4% of its content. Some of these RGP encode a recombinase and IS elements which are indicative of genomic instability. CDS playing part in virulence were identified in this genome such as those involved in mammalian cell entry or encoding a superoxide dismutase. CDS encoding non ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) were identified, with some being likely involved in the synthesis of siderophores and toxins. COG analyses showed this genome to have an organization similar to environmental Actinobacteria. CONCLUSION: N. cyriacigeorgica GUH-2 genome shows features suggesting a diversification from an ancestral saprophytic state. GUH-2 ability at acquiring foreign DNA was found significant and to have led to functional changes likely beneficial for its environmental cycle and opportunistic colonization of a human host.

Ultrasonographic characterization of the feline cardia and pylorus in 34 healthy cats and three abnormal cats.

A prospective study was performed in 34 fasted healthy cats to describe the normal ultrasonographic anatomy of the cardia and pylorus. Measurements were obtained for the caudal esophageal wall thickness (Ew), cardia wall thickness (Cw), pyloric wall thickness (Pw), thickness of the pyloric muscularis (Mp), length of the thicker part of the proximal duodenal submucosa (Dl). Among the 34 cats, 24 were examined using a linear transducer, and 10 with a microconvex transducer. Ew and Cw could be measured in 70% of the cats when a linear transducer was used, in 100% of the cats when a microconvex probe was used, Pw and Mp could be measured in 100% of the cats whatever probe was used. The submucosa of the most proximal part of the duodenum was thicker in half of the cats in longitudinal section. The muscularis layer of the pylorus was triangular in longitudinal section and thicker than the muscularis of the proximal duodenum. The mean for Ew, Cw, Pw, Mp, and DI was 4.9 mm (SD = 1.1), 5 mm (SD = 0.6), 4.4 mm (SD = 0.6), 2.5 mm (SD = 0.5), and 4.7 mm (SD = 2.38), respectively. Three cats with abnormalities of the cardia and pylorus are also described to illustrate clinical implications.

Fetal and neonatal exposure to the mycotoxin zearalenone induces phenotypic alterations in adult rat mammary gland.

Zearalenone is a mycotoxin that is widespread in cereal food. We questioned whether this mycotoxin, administered during known critical exposure periods such as the fetal period and the first days of life, at doses compatible with mean daily intake in humans, could have an effect on mammary gland development in rodents. Wistar female rats were exposed to zearalenone (0.2 µg/kg to 5mg/kg) during the last 14 days of fetal life and the first 5 post-natal days (PND). The mammary tissue was examined for development and maturation by morphologic analyses and immunochemistry. At PND 30, the mean length of terminal buds was significantly enhanced in all of the zearalenone-exposed females (p<0.05). The mammary tissue, as evaluated by scoring of tissue slides, was significantly more differentiated in the 1mg/kg treated group than in controls (p<0.05). At PND 180, mammary tissue was more differentiated in all of the zearalenone treated groups (p<0.05). At six months, 4 of 18 females exposed to 5mg/kg of zearalenone presented mammary hyperplasia lesions. The induction of phenotypic alterations by zearalenone administered in utero and in the neonatal period at doses as low as 0.2 µg/kg suggests that zearalenone could contribute to the induction of breast endocrine disorders.

BSE infection of the small short-lived primate Microcebus murinus.

Eleven Microcebus murinus (lemur) primates were intracerebrally or orally infected by bovine spongiform encephalopathy (BSE) or macaque-adapted BSE (MBSE) brain homogenates. In many BSE and MBSE infected lemurs, but not in animals inoculated with normal bovine brain, persistent behavioral changes occurred as early as 3 months, and neurological signs as early as 13 months after infection. Immunohistochemical examination of animals sacrificed during the incubation period revealed an abnormal accumulation of 'prion' protein (PrP) in the intestinal wall, intestinal nervous plexus, mesenteric lymph nodes and spleen, and in the clinical stage, also in the brain. In MBSE-inoculated animals, proteinase K resistance of the PrP (PrPres) was confirmed by Western blot in the spleen and the brain. Obvious signs of neurodegeneration were observed in all infected animals characterized by hyperaggregated and paired-helical filaments-immunoreactive Tau proteins, beta 42-amyloid plaques and astrogliosis. Additionally, PrPres was present in the ganglion cells of the retina in diseased animals after either intracerebrally or oral infection by the BSE or MBSE agent. These results show that the microcebe is susceptible to the BSE infectious agent via intracerebral and oral routes with comparatively short incubation periods compared to simians, and could be a useful animal model to study the pathophysiology of disease transmission in primates.