Relationship between rate of infection and markers of inflammation/immunity in Holy Birman cats with feline coronavirus

Feline infectious peritonitis (FIP) and coronavirus disease 19 (COVID-19): Are they similar?

SARS‐CoV‐2 has radically changed our lives causing hundreds of thousands of victims worldwide and influencing our lifestyle and habits. Feline infectious peritonitis (FIP) is a disease of felids caused by the feline coronaviruses (FCoV). FIP has been considered irremediably deadly until the last few years. Being one of the numerous coronaviruses that are well known in veterinary medicine, information on FCoV could be of interest and might give suggestions on pathogenic aspects of SARS‐CoV‐2 that are still unclear. The authors of this paper describe the most important aspects of FIP and COVID‐19 and the similarities and differences between these important diseases. SARS‐CoV‐2 and FCoV are taxonomically distant viruses, and recombination events with other coronaviruses have been reported for FCoV and have been suggested for SARS‐CoV‐2. SARS‐CoV‐2 and FCoV differ in terms of some pathogenic, clinical and pathological features. However, some of the pathogenic and immunopathogenic events that are well known in cats FIP seem to be present also in people with COVID‐19. Moreover, preventive measures currently recommended to prevent SARS‐CoV‐2 spreading have been shown to allow eradication of FIP in feline households. Finally, one of the most promising therapeutic compounds against FIP, GS‐441524, is the active form of Remdesivir, which is being used as one therapeutic option for COVID‐19.

Prevalence of Feline Coronavirus Shedding in German Catteries and Associated Risk Factors

The aim of this prospective study was to determine prevalence and potential risk factors of feline coronavirus (FCoV) shedding. Four consecutive fecal samples of 179 cats from 37 German breeding catteries were analyzed for FCoV ribonucleic acid (RNA) by real-time reverse transcriptase polymerase chain reaction (RT-qPCR). Prevalence of shedding was calculated using different numbers of fecal samples per cat (1–4) and different sampling intervals (5–28 days). Information on potential risk factors for FCoV shedding was obtained by a questionnaire. Risk factor analysis was performed using a generalized linear mixed model (GLMM). Most cats (137/179, 76.5%, 95% confidence interval (CI) 69.8–82.2) shed FCoV at least at once. None of the tested 37 catteries was free of FCoV. Prevalence calculated including all four (76.5%, 95% CI 69.8–82.2) or the last three (73.7%, 95% CI 66.8–79.7) samples per cat was significantly higher than the prevalence calculated with only the last sample (61.5%, 95% CI 54.2–68.3; p = 0.0029 and 0.0175, respectively). Young age was significantly associated with FCoV shedding while the other factors were not. For identification of FCoV shedders in multi-cat households, at least three fecal samples per cat should be analyzed. Young age is the most important risk factor for FCoV shedding.

The Effect of Natural Feline Coronavirus Infection on the Host Immune Response: A Whole-Transcriptome Analysis of the Mesenteric Lymph Nodes in Cats with and without Feline Infectious Peritonitis

Feline infectious peritonitis (FIP) is a coronavirus-induced disease of cats, in which the immune system is known to play a crucial, but complex, role in the pathogenesis. This role is still incompletely understood, with involvement of both host and viral factors. To evaluate differential gene expression and pathway involvement in feline coronavirus (FCoV) infection and FIP, we applied next-generation RNA-sequencing of the mesenteric lymph nodes from cats with naturally-acquired FIP, as well as those with systemic FCoV infection without FIP, and those with neither. Viral infection was associated with upregulation of viral defenses regardless of the disease state, but to a greater degree in FIP. FIP was associated with higher pro-inflammatory pathway enrichment, whilst non-FIP FCoV-positive cats showed lower enrichment of humoral immunity pathways, below that of uninfected cats in the case of immunoglobulin production pathways. This host response is presumed to be protective. In FIP, downregulation of T cell-related processes was observed, which did not occur in non-FIP FCoV-positive cats. These results emphasize the importance of the host’s immune balance in determining the outcome of the FCoV infection.

Increased expression of CD8 marker on T-cells in COVID-19 patients

BACKGROUND

Cell-mediated immunity including T-cells (T helper and cytotoxic) plays an essential role in efficient antiviral responses against coronavirus disease-2019 (COVID-19). Therefore, in this study, we evaluated the ratio and expression of CD4 and CD8 markers in COVID-19 patients to clarify the immune characterizations of CD4 and CD8 T-cells in COVID-19 patients.

METHODS

Peripheral blood samples of 25 COVID-19 patients and 25 normal individuals with similar age and sex as the control group were collected. White blood cells, platelets, and lymphocytes were counted and CD4 and CD8 T lymphocytes were evaluated by flow cytometry.

RESULTS

The number of white blood cells, lymphocytes, and platelets were reduced significantly in COVID-19 patients (P < 0.05). The difference in CD4:CD8 ratio, CD4 T-cell frequency, CD8 T-cell frequency, and CD4 mean fluorescence intensity (MFI) was not significant between COVID-19 patients and healthy individuals (P > 0.05); however, the CD8 MFI increased significantly in COVID-19 infected patients (P < 0.05).

CONCLUSION

Although, there is no significant difference in the ratio of CD4 to CD8 between two groups, the expression level of CD8 in COVID-19 patients was significantly higher than the normal individuals. This result suggested that the cellular immune responses triggered by COVID-19 infection were developed through overexpression of CD8 and hyperactivation of cytotoxic T lymphocytes.

Comparison of three blood transfusion guidelines applied to 31 feline donors to minimise the risk of transfusion-transmissible infections

Objectives The increased demand for animal blood transfusions creates the need for an adequate number of donors. At the same time, a high level of blood safety must be guaranteed and different guidelines (GLs) deal with this topic. The aim of this study was to evaluate the appropriateness of different GLs in preventing transfusion-transmissible infections (TTI) in Italian feline blood donors. Methods Blood samples were collected from 31 cats enrolled as blood donors by the owners' voluntary choice over a period of approximately 1 year. Possible risk factors for TTI were recorded. Based on Italian, European and American GLs, specific TTI, including haemoplasmas, feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), Anaplasma phagocytophilum, Ehrlichia species, Bartonella species, Babesia species, Theileria species, Cytauxzoon species, Leishmania donovani sensu lato and feline coronavirus (FCoV), were screened. Rapid antigen and serological tests and biomolecular investigations (PCR) were used. Several PCR protocols for haemoplasma and FeLV DNA were compared. Results The presence of at least one recognised risk factor for TTI was reported in all cats. Results for FIV and FeLV infections were negative using rapid tests, whereas five (16.1%) cats were positive for FCoV antibodies. Four (12.9%) cats were PCR positive for haemoplasma DNA and one (3.2%) for FeLV provirus, the latter being positive only using the most sensitive PCR protocol applied. Other TTI were not detected using PCR. Conclusions and relevance Blood safety increases by combining the recommendations of different GLs. To reduce the risk of TTI, sensitive tests are needed and the choice of the best protocol is a critical step in improving blood safety. The cost and time of the screening procedures may be reduced if appropriate tests are selected. To this end, the GLs should include appropriate recruitment protocols and questionnaire-based risk profiles to identify suitable donors.

Frequency of electrophoretic changes consistent with feline infectious peritonitis in two different time periods (2004-2009 vs 2013-2014)

Objectives The aim of this study was to evaluate whether the frequency of electrophoretic changes in serum of cats with feline infectious peritonitis (FIP) changed in recent years vs past years. Methods Agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) from cats with FIP and healthy cats recorded in the periods 2004-2009 and 2013-2014 were retrospectively analysed. Relative and absolute values of each electrophoretic fraction were recorded and the number of cats showing single or combined electrophoretic changes consistent with FIP (hypoalbuminaemia, inverted albumin to globulin [A:G] ratio, increased total protein, total globulin, alpha [α]2-globulin and gamma [γ]-globulin concentration) were counted. Additionally, a visual analysis of electrophoretograms was also performed. Results for the two time periods were statistically compared. Results The details of 91 AGE procedures (41 from cats with FIP and 50 from healthy cats) and 45 CZE procedures (26 from cats with FIP and 19 from healthy cats) were obtained from the database. No significant differences between the two time periods were found both in FIP and in healthy cats analysed with CZE and in healthy cats analysed with AGE. Compared with 2004-2009, cats with FIP sampled in 2013-2014 with AGE showed a significantly lower concentration of total protein, γ-globulins and total globulins, and a significantly higher A:G ratio and percentage of albumin and α2-globulins. Using both AGE and CZE, in recent years the proportion of cats with high α2-globulins without gammopathy and the proportion of cats with gammopathy alone decreased. With a visual approach, the number of patterns considered as dubious increased in the second period with AGE (non-statistically significant). Conclusions and relevance The frequency of electrophoretic abnormalities in cats with FIP decreased in recent years, independently of the technique employed. Although the mechanism responsible for this change was not investigated in this study, this altered frequency may decrease the diagnostic accuracy of serum protein electrophoresis for FIP.