Involvement of the different lung compartments in the pathogenesis of pH1N1 influenza virus infection in ferrets.

Severe cases after pH1N1 infection are consequence of interstitial pneumonia triggered by alveolar viral replication and an exacerbated host immune response, characterized by the up-regulation of pro-inflammatory cytokines and the influx of inflammatory leukocytes to the lungs. Different lung cell populations have been suggested as culprits in the unregulated innate immune responses observed in these cases. This study aims to clarify this question by studying the different induction of innate immune molecules by the distinct lung anatomic compartments (vascular, alveolar and bronchiolar) of ferrets intratracheally infected with a human pH1N1 viral isolate, by means of laser microdissection techniques. The obtained results were then analysed in relation to viral quantification in the different anatomic areas and the histopathological lesions observed. More severe lung lesions were observed at 24 h post infection (hpi) correlating with viral antigen detection in bronchiolar and alveolar epithelial cells. However, high levels of viral RNA were detected in all anatomic compartments throughout infection. Bronchiolar areas were the first source of IFN-α and most pro-inflammatory cytokines, through the activation of RIG-I. In contrast, vascular areas contributed with the highest induction of CCL2 and other pro-inflammatory cytokines, through the activation of TLR3.

Clinical response to pandemic H1N1 influenza virus from a fatal and mild case in ferrets.

BACKGROUND: The majority of pandemic 2009 H1N1 (A(H1N1)pdm09) influenza virus (IV) caused mild symptoms in most infected patients, however, a greater rate of severe disease was observed in healthy young adults and children without co-morbid conditions. The purpose of this work was to study in ferrets the dynamics of infection of two contemporary strains of human A(H1N1)pdm09 IV, one isolated from a patient showing mild disease and the other one from a fatal case. METHODS: Viral strains isolated from a patient showing mild disease-M (A/CastillaLaMancha/RR5661/2009) or from a fatal case-F (A/CastillaLaMancha/RR5911/2009), both without known comorbid conditions, were inoculated in two groups of ferrets and clinical and pathological conditions were analysed. RESULTS: Mild to severe clinical symptoms were observed in animals from both groups. A clinical score distribution was applied in which ferrets with mild clinical signs were distributed on a non-severe group (NS) and ferrets with severe clinical signs on a severe group (S), regardless of the virus used in the infection. Animals on S showed a significant decrease in body weight compared to animals on NS at 4 to 7 days post-infection (dpi). Clinical progress correlated with histopathological findings. Concentrations of haptoglobin (Hp) and serum amyloid A (SAA) increased on both groups after 2 dpi. Clinically severe infected ferrets showed a stronger antibody response and higher viral titres after infection (p = 0.001). CONCLUSIONS: The severity in the progress of infection was independent from the virus used for infection suggesting that the host immune response was determinant in the outcome of the infection. The diversity observed in ferrets mimicked the variability found in the human population.

Heterogeneous pathological outcomes after experimental pH1N1 influenza infection in ferrets correlate with viral replication and host immune responses in the lung.

The swine-origin pandemic (p) H1N1 influenza A virus causes mild upper-respiratory tract disease in most human patients. However, some patients developed severe lower-respiratory tract infections with fatal consequences, and the cause of these infections remain unknown. Recently, it has been suggested that different populations have different degrees of susceptibility to pH1N1 strains due to host genetic variations that are associated with inappropriate immune responses against viral genetic characteristics. Here, we tested whether the pathologic patterns of influenza strains that produce different disease outcomes in humans could be reproduced in a ferret model. Our results revealed that the severities of infection did not correspond to particular viral isolate and were not associated with the clinical phenotypes of the corresponding patients. Severe pathological outcomes were associated with higher viral replication, especially in alveolar areas, and with an exacerbated innate cellular immune response that was characterised by substantial phagocytic and cytotoxic cell migration into the lungs. Moreover, detrimental innate cellular responses were linked to the up-regulation of several proinflammatory cytokines and chemokines and the down-regulation of IFNα in the lungs. Additionally, severe lung lesions were associated with greater up-regulations of pro-apoptotic markers and higher levels of apoptotic neutrophils and macrophages. In conclusion, this study confirmed that the clinicopathological outcomes of pH1N1 infection in ferrets were not only due to viral replication abilities but also depended on the hosts' capacities to mount efficient immune responses to control viral infection of the lung.

Bacterial diskospondylitis in juvenile mink from 2 Ontario mink farms.

Nine juvenile mink with hind-limb paresis/paralysis from 2 Ontario farms were submitted for necropsy. Diagnostic tests revealed spinal compression and severe thoracic diskospondylitis with intralesional Gram-positive coccoid bacterial colonies. Streptococcus canis, Streptococcus dysgalactiae subsp. equisimilis, and hemolytic Staphylococcus spp. were isolated from vertebral lesions.

Discospondylite bactérienne chez des jeunes visons provenant de 2 fermes de visons de l'Ontario. Neuf jeunes visons atteints d'une parésie/paralysie des membres postérieurs provenant de 2 fermes de l'Ontario ont été soumis à une nécropsie. Les tests diagnostiques ont révélé une compression médullaire et une discospondylite thoracique grave avec des colonies de bactéries coccoïdes à Gram positif. Les bactéries Streptococcus canis, Streptococcus dysgalactiae subsp. equisimilis, et Staphylococcus spp. hémolytiques ont été isolés des lésions vertébrales.(Traduit par Isabelle Vallières).

Giant splenic myelolipoma in a cat with hyperthyroidism.

Case summary: A 15 shorthair cat presented after having fallen down the stairs. Examination by the referring veterinarian had demonstrated tachycardia and a large abdominal mass. The cat was referred for investigations. Blood tests demonstrated hyperthyroidism. A large, poorly vascularised abdominal mass was identified on ultrasonography. The mass was hyperechoic compared with the normal liver; however, the origin could not be determined. Fine-needle aspirate biopsies of the mass demonstrated extramedullary haematopoiesis. Surgical exploration revealed a 12 cm × 8 cm × 8 cm pale mass arising from the spleen. Histopathology determined this was a giant splenic myelolipoma. Relevance and novel information: Splenic myelolipoma is rarely reported in the domestic cat, with only five cases documented within the literature, and none of these having described giant myelolipoma. Indeed, giant myelolipomas are rarely reported in the human literature and are most commonly adrenal in origin. The pathogenesis of these masses is unclear; there have been several incidences in people with endocrine disorders, and it has been hypothesised that their occurrence may be related to endocrine stimulation. Here we report the first case of giant myelolipoma in a hyperthyroid cat.

Inactivated pandemic 2009 H1N1 influenza A virus human vaccines have different efficacy after homologous challenge in the ferret model.

BACKGROUND: The 2009 pandemic H1N1 (A(H1N1)pdm09) influenza A virus (IAV) has replaced the previous seasonal H1N1 strain in humans and continues to circulate worldwide. The comparative performance of inactivated A(H1N1)pdm09 influenza vaccines remains of considerable interest. The objective of this study was to evaluate the efficacy of two licensed A(H1N1)pdm09 inactivated vaccines (AS03B adjuvanted split virion Pandemrix from GlaxoSmithKline and referred here as (V1) and non-adjuvanted whole virion Celvapan from Baxter and referred here as (V2)) in ferrets as a pre-clinical model for human disease intervention. METHODS: Naïve ferrets were divided into two groups (V1 and V2) and immunised intramuscularly with two different A/California/07/2009-derived inactivated vaccines, V1 administered in a single dose and V2 administered in 2 doses separated by 21 days. Six weeks after the first immunisation, vaccinated animals and a non-vaccinated control (NVC) group were intra-nasally challenged with 106.5 TCID50 of the isolate A/England/195/2009 A(H1N1)pdm09 with 99.1% amino acid identity to the vaccine strain. Clinical signs, lung histopathology, viral quantification and antibody responses were evaluated. RESULTS AND CONCLUSIONS: Results revealed important qualitative differences in the performance of both inactivated vaccines in relation to protection against challenge with a comparable virus in a naive animal (ferret) model of human disease. Vaccine V1 limited and controlled viral shedding and reduced lower respiratory tract infection. In contrast, vaccine V2 did not control infection and animals showed sustained viral shedding and delayed lower respiratory infection, resulting in pulmonary lesions, suggesting lower efficacy of V2 vaccine.

Temperate conditions restrict Japanese encephalitis virus infection to the mid-gut and prevents systemic dissemination in Culex pipiens mosquitoes.

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is the main cause of viral encephalitis in Asia. However, with changing climate JEV has the potential to emerge in novel temperate regions. Here, we have assessed the vector competence of the temperate mosquito Culex pipiens f. pipiens to vector JEV genotype III at temperatures representative of those experienced, or predicted in the future during the summer months, in the United Kingdom. Our results show that Cx. pipiens is susceptible to JEV infection at both temperatures. In addition, at 25 °C, JEV disseminated from the midgut and was recovered in saliva samples, indicating the potential for transmission. At a lower temperature, 20 °C, following an incubation period of fourteen days, there were reduced levels of JEV dissemination and virus was not detected in saliva samples. The virus present in the bodies of these mosquitoes was restricted to the posterior midgut as determined by microscopy and viable virus was successfully recovered. Apart from the influence on virus dissemination, mosquito mortality was significantly increased at the higher temperature. Overall, our results suggest that temperature is a critical factor for JEV vector competence and infected-mosquito survival. This may in turn influence the vectorial capacity of Cx. pipiens to vector JEV genotype III in temperate areas.

Classical Scrapie Did Not Re-occur in Goats After Cleaning and Disinfection of the Farm Premises.

After an outbreak of classical scrapie in a dairy goat herd with over 1,800 goats, all goats in the herd were culled in 2008, cleaning and disinfection of the premises was implemented, and restocking with goats took place ~4 months after depopulation. Ten years later the new herd population is over 3,000 goats. This study was carried out to determine whether the measures were effective to prevent re-occurrence of scrapie to the 1% prevalence level seen when scrapie was first detected on this farm. A total of 280 goats with a minimum age of 18 months, which were predominantly at the end of their productive life, were euthanized, and brain and retropharyngeal lymph node examined by immunohistochemistry for disease-associated prion protein. Genotyping was done in all euthanized goats and live male goats used or intended for breeding to determine prion protein gene polymorphisms associated with resistance to classical scrapie. None of the goats presented with disease-associated prion protein in the examined tissues, and 34 (12.2%) carried the K222 allele associated with resistance. This allele was also found in four breeding male goats. The study results suggested that classical scrapie was not re-introduced on this goat farm through mass restocking or inadequate cleaning and disinfection procedures. Further scrapie surveillance of goats on this farm is desirable to confirm absence of disease. Breeding with male goats carrying the K222 allele should be encouraged to increase the scrapie-resistant population.

Fibrocartilaginous Embolic Encephalopathy in a Pig.

A 1-year-old boar was investigated after presenting with acute onset collapse and obtundance. No significant gross lesions were observed at post-mortem examination. Histopathological investigation revealed a severe bilateral and multifocal necrotizing encephalopathy with an amorphous material, which obstructed neuroparenchymal vessels in the metencephalon and mesencephalon. Alcian blue staining identified the material as of cartilaginous origin and a diagnosis of cerebral fibrocartilaginous embolism was established. No gross evidence of vertebral disc disease was detected and the origin of the embolic material was not found. Although cerebral fibrocartilaginous embolism has been reported in a human, and rarely in animals, it has not been reported previously in the pig.

The Role of Birds of Prey in West Nile Virus Epidemiology.

Reported human cases of West Nile virus (WNV) in Europe increased dramatically in 2018. Lineage 1 strains had been circulating in Euro-Mediterranean countries since the early 1990s. The subsequent introduction of WNV lineage 2 has been responsible for the remarkable upsurge of European WNV outbreaks since 2004, including the dramatic increase in human cases observed since 2018. The virus exists in a natural cycle between mosquitoes and wild birds, with humans and horses acting as dead-end hosts. As the key vertebrate hosts in the transmission cycle of WNV, avian species have been the focus of surveillance across many countries. Raptors appear particularly susceptible to WNV infection, resulting in higher prevalence, and in some cases exhibiting neurological signs that lead to the death of the animal. In addition, birds of prey are known to play an important role as WNV reservoir and potentially amplifying hosts of infection. Importantly, raptor higher susceptibility/prevalence may indicate infection through predation of infected prey. Consequently, they are considered important target species when designing cost-effective surveillance for monitoring both seasonal WNV circulation in endemic countries and its emergence into new areas, where migrating raptors may play a critical role in virus introduction. This review summarizes the different aspects of the current knowledge of WNV infection in birds of prey and evaluates their role in the evolution of the epizootic that is spreading throughout Europe.

West Nile Virus spread and differential chemokine response in the central nervous system of mice: Role in pathogenic mechanisms of encephalitis.

West Nile virus (WNV) is a zoonotic mosquito-borne flavivirus able to cause severe neurological disease in humans, horses and various avian species. The more severe pathological changes of neurotropic WNV infection are caused by virus neuroinvasion and/or the immunological response in the central nervous system (CNS). The extent in which inflammatory cell trafficking orchestrated by chemokines is involved in the pathogenesis of CNS lesions has not been entirely elucidated. To understand the sequence of pro-inflammatory chemokine induction during WNV encephalitis, a murine intranasal inoculation model was used. The relationship between lesional patterns in the mice CNS, the viral antigen distribution and the expression of pro-inflammatory chemokine (CCL2, CCL5 and CXCL10) were evaluated. Viral antigen was first observed in olfactory tract and pyriform cortex neurons, suggesting a retrograde neuronal infection from the olfactory nerve. A spatio-temporal association between WNV antigen and perivascular cuffs development was observed. Chemokine immunostaining was widely distributed in the brain from early stages. CCL2 immunolabelling was localised in neurons, astrocytes, microglia and endothelial cells as well as mononuclear leucocytes within perivascular cuffs. In contrast, CCL5 and CXCL10 immunostaining were mainly observed in astroglia and neurons, respectively. A strong correlation was demonstrated between the presence of perivascular cuffs and CCL2 and CCL5 expression in most brain areas, while CXCL10 was only associated with inflammatory lesions in few specific regions. Importantly, a strong correlation between WNV and CCL5 distribution was observed. However, no correlation was observed between CXCL10 and viral antigen. Neurons were confirmed as the main target cells of WNV, as well as one of the sources of CCL2, CCL5 and CXCL10. This study shows the sequence and comparative distribution pattern between histological lesions, WNV antigen and chemokine expression over the infection process. Furthermore, it identifies potential targets for immune intervention to suppress damaging chemokine responses.

Differential Viral-Host Immune Interactions Associated with Oseltamivir-Resistant H275Y and Wild-Type H1N1 A(pdm09) Influenza Virus Pathogenicity.

Oseltamivir is a common therapy against influenza A virus (IAV) infections. The acquisition of oseltamivir resistance (OR) mutations, such as H275Y, hampers viral fitness. However, OR H1N1 viruses have demonstrated the ability to spread throughout different populations. The objective of this work was to compare the fitness of two strains of OR (R6 and R7) containing the H275Y mutation, and a wild-type (F) pandemic influenza A (H1N1) 2009 (pdm09) virus both in vitro and in vivo in mice and to select one OR strain for a comparison with F in ferrets. R6 showed faster replication and pathogenicity than R7 in vitro and in mice. Subsequently, R6 was selected for the fitness comparison with the F strain in ferrets. Ferrets infected with the F virus showed more severe clinical signs, histopathological lung lesions, and viral quantification when compared to OR R6-infected animals. More importantly, differential viral kinetics correlated with differential pro-inflammatory host immune responses in the lungs of infected ferrets, where OR-infected animals developed a protective higher expression of type I IFN and Retinoid acid Inducible Gene I (RIG-I) genes early after infection, resulting in the development of milder disease. These results suggest the presence of early specific viral-host immune interactions relevant in the development of influenza-associated lung pathology.

The Scrapie Prevalence in a Goat Herd Is Underestimated by Using a Rapid Diagnostic Test.

Current European surveillance regulations for scrapie, a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease in sheep and goats, require testing of fallen stock or healthy slaughter animals, and outline measures in the case of confirmation of disease. An outbreak of classical scrapie in a herd with 2500 goats led to the culling of the whole herd, providing the opportunity to examine a subset of goats, take samples, and examine them for the presence of disease-associated prion protein (PrPSc) to provide further information on scrapie test sensitivity, pathology, and association with prion protein genotype. Goats were examined clinically prior to cull, and the brains examined post mortem by Bio-Rad ELISA, a rapid screening test used for active surveillance in sheep and goats, and two confirmatory tests, Western blot and immunohistochemistry. Furthermore, up to 10 lymphoid tissues were examined by immunohistochemistry. Of 151 goats examined, three (2.0%) tested positive for scrapie by ELISA on brain, confirmed by confirmatory tests, and a further five (3.3%) were negative by ELISA but positive by at least one of the confirmatory tests. Only two of these, both positive by ELISA, displayed evident signs of scrapie. In addition, 10 (6.6%) goats, which also included two clinical suspects, were negative on brain examination but had detectable PrPSc in lymphoid tissue. PrPSc was detected most frequently in the medial retropharyngeal lymph node (LN; 94.4% of all 18 cases) and palatine tonsil (88.9%). Abnormal behavior and circling or loss of balance when blindfolded were the best clinical discriminators for scrapie status. None of the goats that carried a single allele in the prion protein gene associated with increased resistance to scrapie (Q211, K222, S146) were scrapie-positive, and the percentage of goats with these alleles was greater than expected from previous surveys. Significantly more goats that were scrapie-positive were isoleucine homozygous at codon 142 (II142). The results indicate that the sensitivity of the applied screening test is poor in goats compared to the confirmatory tests as gold standard, particularly for asymptomatic animals. Sensitivity of surveillance could be improved by testing retropharyngeal LN or palatine tonsil in addition to brain.

Pulmonary transcriptomic responses indicate a dual role of inflammation in pneumonia development and viral clearance during 2009 pandemic influenza infection.

BACKGROUND: The interaction between influenza virus and the host response to infection clearly plays an important role in determining the outcome of infection. While much is known on the participation of inflammation on the pathogenesis of severe A (H1N1) pandemic 09-influenza virus, its role in the course of non-fatal pneumonia has not been fully addressed. METHODS: A systems biology approach was used to define gene expression profiles, histology and viral dynamics in the lungs of healthy immune-competent mice with pneumonia caused by a human influenza A (H1N1) pdm09 virus, which successfully resolved the infection. RESULTS: Viral infection activated a marked pro-inflammatory response at the lung level paralleling the emergence of histological changes. Cellular immune response and cytokine signaling were the two signaling pathway categories more representative of our analysis. This transcriptome response was associated to viral clearance, and its resolution was accompanied by resolution of histopathology. DISCUSSION: These findings suggest a dual role of pulmonary inflammation in viral clearance and development of pneumonia during non-fatal infection caused by the 2009 pandemic influenza virus. Understanding the dynamics of the host's transcriptomic and virological changes over the course of the infection caused by A (H1N1) pdm09 virus may help identifying the immune response profiles associated with an effective response against influenza virus.

Liposarcoma in animals: literature review and case report in a domestic pig (Sus scrofa).

Liposarcomas are malignant tumors of adipocytes. The current report describes a liposarcoma in a 2.5-year-old, mixed-breed commercial sow that was detected during meat inspection. On gross examination, a firm, whitish, multinodular, 20 cm ×10 cm mass was observed in the perirenal area along with smaller nodules multifocally scattered within the renal parenchyma. Histological examination revealed an anaplastic sarcoma with clear intracytoplasmic lipidic vacuoles that were positive for Sudan black staining. Most of the cells were also positive for S100 and vimentin immunohistochemistry. Based on these results, a diagnosis of a perirenal liposarcoma was established. To the authors' knowledge, no previous reports of liposarcomas in pigs have been published. This report also includes a review of the literature published on animal liposarcomas.