A computational study of the interface interaction between SARS-CoV-2 RBD and ACE2 from human, cat, dog, and ferret.

The total impact of the worldwide COVID-19 pandemic is still emerging, changing all relationships as a result, including those with pet animals. In the infection process, the use of angiotensin-converting enzyme 2 (ACE2) as a cellular receptor to the spike protein of the new coronavirus is a fundamental step. In this sense, understanding which residue plays what role in the interaction between SARS-CoV-2 spike glycoprotein and ACE2 from cats, dogs, and ferrets is an important guide for helping to choose which animal model can be used to study the pathology of COVID-19, and if there are differences between these interactions and those occurring in the human system. To help answer these questions, we performed classical molecular dynamics simulations to evaluate, from an atomistic point of view, the interactions in these systems. Our results show that there are significant differences in the interacting residues between the systems from different animal species, and the role of ACE2 key residues are different in each system, and can assist in the search for different inhibitors for each animal.

Genomic Analysis of Novel Poxvirus Brazilian Porcupinepox Virus, Brazil, 2019.

We obtained the complete sequence of a novel poxvirus, tentatively named Brazilian porcupinepox virus, from a wild porcupine (Coendou prehensilis) in Brazil that had skin and internal lesions characteristic of poxvirus infection. The impact of this lethal poxvirus on the survival of this species and its potential zoonotic importance remain to be investigated.

Extinction and emergence of genomic haplotypes during the evolution of Avian coronavirus in chicken embryos.

Avian coronavirus (AvCoV) is ubiquitously present on poultry as a multitude of virus lineages. Studies on AvCoV phenotypic traits are dependent on the isolation of field strains in chicken embryonated eggs, but the mutant spectrum on each isolate is not considered. This manuscript reports the previously unknown HTS (high throughput sequencing)-based complete genome haplotyping of AvCoV isolates after passages of two field strains in chicken embryonated eggs. For the first and third passages of strain 23/2013, virus loads were 6.699 log copies/ µL and 6 log copies/ µL and, for 38/2013, 5.699 log copies/µL and 2.699 log copies/µL of reaction, respectively. The first passage of strain 23/2013 contained no variant haplotype, while, for the third passage, five putative variant haplotypes were found, with > 99.9% full genome identity with each other and with the dominant genome. Regarding strain 38/2013, five variant haplotypes were found for the first passage, with > 99.9% full genome identity with each other and with the dominant genome, and a single variant haplotype was found. Extinction and emergence of haplotypes with polymorphisms in genes involved in receptor binding and regulation of RNA synthesis were observed, suggesting that phenotypic traits of AvCoV isolates are a result of their mutant spectrum.

Complete Genome Sequence of Avian Coronavirus Strain D274.

Avian coronavirus, the causative agent of avian infectious bronchitis, occurs as multiple genotypes and lineages, and full genomes are not available for the majority of them. This paper reports the (previously unknown) complete genome sequence of strain D274 of this virus (27,599 nucleotides), isolated from chickens in The Netherlands in 1979.

Experimental Neospora caninum infection in chickens (Gallus gallus domesticus) with oocysts and tachyzoites of two recent isolates reveals resistance to infection.

The importance of birds in the biological cycle of Neospora caninum is not clear. We report unsuccessful Neospora infection in chickens (Gallus gallus domesticus) using two isolates of N. caninum. In experiment #1, 30 White Leghorn chickens were orally inoculated with viable N. caninum oocysts (NC-SP1 isolate, 200 oocysts per bird) via the crop at 21days of age. Groups of three birds were euthanised at intervals of 7days (a total of 9weeks) and one group was challenged with the same oocyst dose at 37daysp.i. and observed for 11weeks. Blood samples were collected weekly, and sera were tested using IFAT. Chicken tissues were collected for PCR, quantitative PCR and immunohistochemistry. Two dogs approximately 45days of age were fed with tissues from chickens euthanised at 138 and 159daysp.i. The results indicated that the chickens were resistant to neosporosis as revealed by failure to seroconvert, to detect parasite DNA or N. caninum antigen by immunohistochemistry in inoculated bird tissues, and by no oocyst excretion by the dogs fed avian tissues. Similar results were obtained in experiment #2, in which 34 1-week-old chickens were each s.c. inoculated with 100,000 tachyzoites of the NcWTDMn1 isolate of N. caninum. The chickens were euthanised on days 7, 15, 22, 28, 36 and 60p.i. At necropsy, all tissues and serum from each bird were collected. All chickens remained asymptomatic, and N. caninum antigen was not detected by immunohistochemistry. Seven chickens euthanised at day 60p.i. demonstrated low (1:25 dilution) levels of antibodies by using the Neospora agglutination test. Two 12-week-old dogs fed tissues pooled from 10 inoculated chickens euthanised at day 60p.i. did not excrete N. caninum oocysts. This investigation indicates that chickens are resistant to experimental infection by N. caninum.

Complete Genome of Avian coronavirus Vaccine Strains Ma5 and BR-I.

Avian coronavirus (AvCoV) is a ubiquitous multiple-serotype pathogen of poultry, and its control is mainly based on the use of vaccines. We report here the previously unknown full genomes of the Ma5 (27,652 nucleotides [nt]) and BR-I (27,618 nt) AvCoV vaccine strains of the GI-1 (Massachusetts) and GI-11 (Brazil) types.

Report of the first clinical case of intestinal trichomoniasis caused by Tritrichomonas foetus in a cat with chronic diarrhoea in Brazil.

BACKGROUND: Tritrichomonas foetus is an emergent and important enteric pathogen of cats, which causes prolonged diarrhoea in cats. CASE PRESENTATION: This study describes a T. foetus infection in a seven-month-old, entire male domestic shorthair kitten with a six-month history of persistent large intestinal diarrhoea, faecal incontinence, prostration, apathy and weight loss. Parasites were microscopically observed and confirmed by PCR and DNA sequencing. Molecular analyses were carried out comparing the sequence obtained in this study with T. foetus and T. suis. Retrieved from GenBank. After treatment with ronidazole, the cat showed resolution of clinical signs. CONCLUSIONS: This is the first clinical case of T. foetus infection in a chronic diarrheic cat in Brazil and South America, confirming the presence of this pathogen in this part of the world and highlighting the importance of this protozoa being considered in the differential diagnosis of cats presenting diarrhoea of the large intestine. Our case report enriches our knowledge on the geographical distribution of T. foetus in cats in Brazil and provides further understanding of the clinical significance of feline intestinal trichomoniasis in this country.

Complete Genome Sequence of a Brazil-Type Avian coronavirus Detected in a Chicken.

Avian coronavirus is the causative agent of infectious bronchitis in chickens, leading to multisystemic disease that might be controlled if adequate vaccine strains are used. This paper reports the first complete genome sequence of a Brazil type of this virus (27,615 nucleotides [nt]) isolated from the kidneys of a chicken.

Glial response in the central nervous system of cats with feline infectious peritonitis.

OBJECTIVES: The aim of the study was to evaluate central nervous system (CNS) lesions in non-effusive and effusive cases of feline infectious peritonitis (FIP) regarding aspects related to astrocytic and microglial reactions. METHODS: Five necropsied cats that were naturally infected with FIP virus, confirmed by reverse transcriptase polymerase chain reaction and immunohistochemistry, with different intensities of CNS lesions, were studied. Brain and cerebellum were evaluated by light microscopy and immunohistochemistry for glial fibrillary acidic protein (GFAP) and vimentin to assess astrocytic morphology, and lectin histochemistry for Ricinus communis agglutinin-I (RCA-I) to detect microglia was performed to evaluate the glial response in the CNS of cats with FIP. RESULTS: An important astrocytic response in many areas of the CNS of all cats, including the periventricular areas of lateral ventricles and fourth ventricle, the molecular layer of the cerebellum and cerebral cortex, was visualized. This astrocytic reactivity was associated with areas of granulomatous or pyogranulomatous vasculitis/perivasculitis in most cases, and it was characterized by multifocal to coalescing astrocytosis and astrogliosis with an increase in the expression of intermediate filaments, such as GFAP. However, astrocytes exhibited strong vimentin expression in neuroparenchyma with severe inflammatory and necrotic changes, but GFAP expression was mild or absent in these cases. A microglial response was present only in severe lesions, and RCA-I expression was detected primarily in gitter cells and resting microglia. CONCLUSIONS AND RELEVANCE: The present study indicates a strong astrocytic response, including the presence of many less differentiated vimentin-positive astrocytes and gitter cells positive for RCA-1 in severe lesions in the CNS of cats with FIP.

Phylogenetic analyses of the VP4 and VP7 genes of porcine group A rotaviruses in Sao Paulo State, Brazil: first identification of G5P[23] in piglets.

This study determined the group A rotavirus occurrence in pig farms from 7 different cities in São Paulo State, Brazil. Out of 143 samples, 70 tested positive. Sequence analyses of 37 strains indicated that the strains had the G3, G5, G9, and P[6], P[13]/P[22]-like, and P[23] genotypes.

Intrahost diversity of feline coronavirus: a consensus between the circulating virulent/avirulent strains and the internal mutation hypotheses?

To evaluate the most controversial issue concerning current feline coronavirus (FCoV) virology, the coexisting hypotheses of the intrahost and interhost origins of feline infectious peritonitis virus (FIPV) in regard to the pathogenesis of feline infectious peritonitis (FIP), this study aimed to assess the molecular diversity of the membrane gene FCoVs in 190 samples from 10 cats with signs of FIP and in 5 faecal samples from cats without signs of FIP. All samples from the non-FIP cats and 25.26% of the samples from the FIP cats were positive for the FCoV membrane (M) gene. Mutations in this gene consisted of SNP changes randomly scattered among the sequences; few mutations resulted in amino acid changes. No geographic pattern was observed. Of the cats without FIP that harboured FECoV, the amino acid sequence identities for the M gene were 100% among cats (Cats 1-3) from the same cattery, and the overall sequence identity for the M gene was ≥91%. In one cat, two different lineages of FCoV, one enteric and one systemic, were found that segregated apart in the M gene tree. In conclusion, the in vivo mutation transition hypothesis and the circulating high virulent-low virulent FCoV hypothesis have been found to be plausible according to the results obtained from sequencing the M gene.

Felid herpesvirus 1 as a causative agent of severe nonsuppurative meningoencephalitis in a domestic cat.

Felid herpesvirus 1 is an important respiratory pathogen of domestic cats. This report presents the first case of severe nonsuppurative meningoencephalitis caused by this virus in a cat.