Feline Infectious Peritonitis Research Articles

Feline Infectious Peritonitis Effusion Index: A Novel Diagnostic Method and Validation of Flow Cytometry-Based Delta Total Nucleated Cells Analysis on the Sysmex XN-1000V®

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led the medical and scientific community to explore the pathogenesis and clinical manifestations of coronaviruses. In felines, a widespread coronavirus known as feline coronavirus (FCoV) can lead to feline infectious peritonitis (FIP), a highly fatal disease characterised by severe systemic inflammation. Diagnosing FCoV remains challenging due to the limited accuracy of the available methods. The present study introduces the FIP Effusion Index, a novel diagnostic method that combines the albumin-to-globulin (ALB/GLOB) ratio with the delta total nucleated cell (∆TNC) count obtained via flow cytometry using the Sysmex XN-1000V® analyser in effusions. Samples from cats (n = 50) with suspected FIP were analysed for ∆TNC, with findings showing that a ∆TNC ≥ 2.1 is highly indicative of FIP and a ∆TNC ≥ 4.9 can be considered diagnostic. The FIP Effusion Index enhanced diagnostic precision in our group of samples, achieving 96.3% sensitivity and 95.7% specificity for values ≥ 5.06, and reaching perfect specificity (100%) with 96.3% sensitivity for values ≥ 7.54. This combined approach surpasses the accuracy of individual parameters, establishing the FIP Effusion Index as a superior diagnostic tool for FIP, with potential applications in both veterinary and human medicine for related coronavirus diseases.

Complement Evasion Protects FCoV from Virus Clearance Within Prototypic FIP Lesions

Feline infectious peritonitis (FIP) is a fatal disease in cats caused by infection with feline coronavirus (FCoV). Despite severe inflammatory changes, defense mechanisms fail to achieve virus clearance. Some studies focused on various immune evasion mechanisms, but none of these studies elucidated the inefficacy of the complement system, which is one major player in FIP-associated immune pathogenesis. This study aimed to investigate the involvement of complement-regulating factors (CRFs). CRFs help modulate the immune response and prevent host tissue damage. Archived tissue samples from 31 deceased, FIP-affected cats were evaluated using multiplex immunohistochemistry for the spatial expression of the complement-regulating factors CD46 and CD59 in association with FIP lesions and their colocalization with complement-activating factor C1q and membrane attack complex C9 in relation to the presence and proximity of FCoV-infected cells. The FIP lesions of all 31 cats exhibited marked expression of both complement-regulating factors in proximity to FCoV-infected macrophages. Moreover, their expression in all 31 animals was significantly lower than the expression of the complement-activating factors C1q and C9 compared to areas farther distal to FCoV-infected cells. In conclusion, FCoV-infected macrophages in cats with FIP appear to use autocrine and paracrine expression of complement-regulating factors in their immediate environment to shield themselves from destruction by the complement system.

Serum proteomic analysis identified ITIH4 as a potential novel biomarker for feline infectious peritonitis

Feline infectious peritonitis (FIP) is a fatal feline disease. At present, the reference standard for FIP diagnosis is immunohistochemistry (IHC) of organs, but this method involves high time-related costs, invasive sampling procedures and professional requirements. Serological detection is a common auxiliary method for diagnosing diseases. As a result, we assessed the changes in the serum proteome of FIP patients with the aim of identifying novel specific serum biomarkers that could aid in the clinical diagnosis of FIP. Pre- and postinfection groups were compared and 92 differentially expressed proteins (DEPs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the DEPs revealed that the enriched GO terms and KEGG pathways among the DEPs were immune activation, peptidase regulator activity and the complement and coagulation cascade pathways. The level of peptidase regulator interalpha-trypsin inhibitor heavy chain 4 (ITIH4) in cat serum was significantly correlated with FIP. The areas under the ROC curve (AUCs) of full-length ITIH4 (f-ITIH4) and cleaved ITIH4 (c-ITIH4) expression were 0.922 and 1.000, respectively, which allowed the discrimination of FIP cats from healthy cats. These results suggest that ITIH4 may be a potential serum biomarker for detecting early FIP. SignificanceFIP causes fatal disease in cats of almost all ages, and there is currently no effective vaccine or treatment for FIP. Therefore, early diagnosis is extremely important for disease prevention and control. The results of the model and clinical samples revealed that ITIH4 was significantly increased in the serum of FIP cats. This study is the first to propose ITIH4 as a diagnostic biomarker in cats with FIP and our results suggest that serum ITIH4 levels might identify cats with FIP during the early stage.

Status of Hemato-biochemical Parameters in Feline Infectious Peritonitis (FIP) Affected Cats

Feline infectious peritonitis (FIP) is a serious viral disease of cats that usually results in death. There is derangement of vitals in cats due to FIP including clinical and hemato-biochemical parameters. This study reports same findings in a group of six cats (3 Persian, 2 mixed breed, 1 nondescript) affected with FIP. Cats were diagnosed on clinical signs, FIP rapid test, Rivalta test, USG and X-ray. Ground glass appearance of abdomen on X-ray, hyperechogenicity of liver and loss of renal/cortical texture on ultrasonography (USG) was noted. Among the liver function tests, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were increased to 76.2400±4.35373 and 58.6333±13.75860 IU/L, respectively. Kidney function tests including bilirubin, blood urea nitrogen (BUN) and creatinine were raised 3.533±0.4601, 62.5000±2.45967 and 2.8833±0.48402 mg/dl, respectively. Hematological values including haemoglobin (Hb) (10.4500±0.76714), red blood cell count (RBC) (7.4400±0.78636), packed cell volume (PCV) (26.7667±3.59042), white blood cell count (WBC) (18.2850±2.72594 103/μl), granulocytes (15.3167±2.84762%), lymphocytes (1.7000±0.34351%) and platelets (310.8333±75.50074) showed derangement. This study establishes baseline data for FIP cases in this region and can serve as a basis of prognosis of FIP based on clinical and hematobiochemical parameters.

A Histopathological Study on the Changes in the Central Nervous System of Dead Cats With Neurological Symptoms

Background: Neurological conditions constitute approximately 10% of feline cases referred to veterinary clinics. Such cases often present manifestations of central nervous system (CNS) damage, including inflammatory lesions, neoplastic growth and structural and cellular transformations. Objectives: This study aimed at identifying histopathological changes in the CNS of cats that had succumbed to neurological symptoms. Methods: Microscopic evaluation of different sections within the CNS was conducted on 20 cats that had either died naturally or were euthanized due to neurological signs. After performing a necropsy, we examined the CNS tissues and conducted PCR testing to screen for possible viral infections, including feline infectious peritonitis (FIP), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). Results: The majority of cases showed characteristic histopathologic lesions, notably mononuclear and suppurative meningoencephalitis, perivascular cuffing, disseminated intravascular coagulation (DIC), granulomatous meningoencephalitis, acute neuronal necrosis, liquefactive necrosis, epididymitis, thrombosis and demyelination. Among the 20 cats studied, 12 tested positive for FIP by PCR analysis, while 5 cats exhibited positive results for FIV. Also, FeLV PCR tests displayed positive results in 4 cats. No evidence of feline spongiform encephalopathy (FSE) was observed. Conclusion: This study is the first of its kind conducted in Iran. Based on the results, the most prevalent viral agents infecting cats’ CNS were FIP, FIV and FeLV. The investigation revealed no evidence of FSE in cats with neurological signs.

Development and characterization of reverse genetics systems of feline infectious peritonitis virus for antiviral research

Feline infectious peritonitis (FIP) is a lethal, immune-mediated disease in cats caused by feline infectious peritonitis virus (FIPV), a biotype of feline coronavirus (FCoV). In contrast to feline enteric coronavirus (FECV), which exclusively infects enterocytes and causes diarrhea, FIPV specifically targets macrophages, resulting in the development of FIP. The transmission and infection mechanisms of this complex, invariably fatal disease remain unclear, with no effective vaccines or approved drugs for its prevention or control. In this study, a full-length infectious cDNA clone of the wild-type FIPV WSU79-1149 strain was constructed to generate recombinant FIPV (rFIPV-WT), which exhibited similar growth kinetics and produced infectious virus titres comparable to those of the parental wild-type virus. In addition, the superfold green fluorescent protein (msfGFP) and Renilla luciferase (Rluc) reporter genes were incorporated into the rFIPV-WT cDNA construct to generate reporter rFIPV-msfGFP and rFIPV-Rluc viruses. While the growth characteristics of the rFIPV-msfGFP virus were similar to those of its parental rFIPV-WT, the rFIPV-Rluc virus replicated more slowly, resulting in the formation of smaller plaques than did the rFIPV-WT and rFIPV-msfGFP viruses. In addition, by replacing the S, E, M, and ORF3abc genes with msfGFP and Rluc genes, the replicon systems repFIPV-msfGFP and repFIPV-Rluc were generated on the basis of the cDNA construct of rFIPV-WT. Last, the use of reporter recombinant viruses and replicons in antiviral screening assays demonstrated their high sensitivity for quantifying the antiviral effectiveness of the tested compounds. This integrated system promises to significantly streamline the investigation of virus replication within host cells, enabling efficient screening for anti-FIPV compounds and evaluating emerging drug-resistant mutations within the FIPV genome.

Development of feline infectious peritonitis diagnosis system by using CatBoost algorithm

This study employed machine learning techniques to predict the rate of feline infectious peritonitis (FIP) diagnoses, with a specific focus on mutations in the spike protein gene of the feline coronavirus (FCoV). FIP is a fatal viral disease affecting the peritoneum of cats and is primarily caused by mutations in FCoV. Its diagnosis largely relies on evaluations of various biomarkers and clinical symptoms. The current analysis of FCoV spike protein gene mutations exhibits certain limitations. To address this problem, the present study employed a large dataset—comprising information on FCoV copy numbers, spike protein mutation outcomes, and related clinical data—and used machine learning models to analyze the association between spike protein gene mutations and FIP diagnosis. Various algorithms were used to establish highly accurate predictive models, namely logistic regression, random forest, decision tree, neural network, support vector machine, gradient boosting tree, and categorical boosting (CatBoost) algorithms. The model obtained using the CatBoost algorithm was discovered to have accuracy of 0.9541. Accordingly, a highly accurate predictive model was developed to enable early diagnosis of FIP and improve the rate of survival in cats. The application of machine learning technology in this study yielded research findings that provide veterinarians with effective tools for managing and preventing FIP, a painful and deadly disease for cats. This study is a pioneering work in the systematic application of multiple machine learning models to the prediction of FIP and comparison of performance results to improve diagnostic accuracy and efficiency. This study is the first of its kind in the field of FIP.

Open label clinical trial of orally administered molnupiravir as a first-line treatment for naturally occurring effusive feline infectious peritonitis.

Before the discovery of effective antiviral drugs, feline infectious peritonitis (FIP) was a uniformly fatal disease of cats. Multiple antiviral treatments have been recognized, but optimization of treatment protocols is needed. To evaluate the efficacy of PO molnupiravir (MPV; EIDD-2801) to treat effusive FIP. Ten cats with naturally occurring effusive FIP and 10 historical control cats with effusive FIP treated with PO GS-441524. A single-center, prospective, open-label longitudinal, non-inferiority trial with historical controls. Ten cats with FIP were enrolled and treated with PO MPV (10-15 mg/kg PO q12h) for 84 days. Cats were evaluated at 0, 6, and 16 weeks, and the proportion of cats in clinical remission at 16 weeks was determined. Survival and clinicopathologic features were compared with historical control cats with effusive FIP treated with PO GS-441524. Eight of the 10 cats treated with MPV survived and were in remission at 16 weeks. The 2 non-survivors died in the first 24 hours of treatment. No adverse events that necessitated discontinuation of treatment were observed. Survival of cats treated with PO MPV was non-inferior to historic control cats treated with PO GS-441524 (5/9 [55%] survived), with a difference in survival of 25% (90% confidence interval, -9.3% to 59.3%). Clinicopathologic features associated with FIP normalized during the study period, and no differences in clinicopathologic data at each study time point were observed when comparing cats treated with MPV and GS-441524. Molnupiravir is an effective antiviral treatment for effusive FIP.

Baicalin Inhibits FIPV Infection In Vitro by Modulating the PI3K-AKT Pathway and Apoptosis Pathway.

Feline infectious peritonitis (FIP), a serious infectious disease in cats, has become a challenging problem for pet owners and the industry due to the lack of effective vaccinations and medications for prevention and treatment. Currently, most natural compounds have been proven to have good antiviral activity. Hence, it is essential to develop efficacious novel natural compounds that inhibit FIPV infection. Our study aimed to screen compounds with in vitro anti-FIPV effects from nine natural compounds that have been proven to have antiviral activity and preliminarily investigate their mechanisms of action. In this study, the CCK-8 method was used to determine the maximum noncytotoxic concentration (MNTC), 50% cytotoxic concentration (CC50), and 50% effective concentration (EC50) of natural compounds on CRFK cells and the maximum inhibition ratio (MIR) of the compounds inhibit FIPV. The effect of natural compounds on FIPV-induced apoptosis was detected via Annexin V-FITC/PI assay. Network pharmacology (NP), molecular docking (MD), and 4D label-free quantitative (4D-LFQ) proteomic techniques were used in the joint analysis the mechanism of action of the screened natural compounds against FIPV infection. Finally, Western blotting was used to validate the analysis results. Among the nine natural compounds, baicalin had good antiviral effects, with an MIR > 50% and an SI > 3. Baicalin inhibited FIPV-induced apoptosis. NP and MD analyses showed that AKT1 was the best target of baicalin for inhibiting FIPV infection. 4D-LFQ proteomics analysis showed that baicalin might inhibit FIPV infection by modulating the PI3K-AKT pathway and the apoptosis pathway. The WB results showed that baicalin promoted the expression of EGFR, PI3K, and Bcl-2 and inhibited the expression of cleaved caspase 9 and Bax. This study found that baicalin regulated the PI3K-AKT pathway and the apoptosis pathway in vitro and inhibited FIPV-induced apoptosis, thus exerting anti-FIPV effects.

β-Tocotrienol and δ-Tocotrienol as Additional Inhibitors of the Main Protease of Feline Infectious Peritonitis Virus: An In Silico Analysis.

Feline infectious peritonitis (FIP) is a severe and invariably fatal disease affecting both domestic and wild felines with limited effective therapeutic options available. By considering the significant immunomodulatory effects of vitamin E observed in both animal and human models under physiological and pathological conditions, we have provided a full in silico investigation of vitamin E and related compounds and their effect on the crystal structure of feline infectious peritonitis virus 3C-like protease (FIPV-3CLpro). This work revealed the β-tocotrienol and δ-tocotrienol analogs as inhibitor candidates for this protein, suggesting their potential as possible drug compounds against FIP or their supplementary use with current medicines against this disease.

Эффективность препарата «Ипекон®» при инфекционном перитоните кошек, доказанная в официально зарегистрированных мультицентровых рандомизированных клинических и постклинических исследованиях

Feline infectious peritonitis is a difficult-to-treat disease caused by a highly virulent biotype of a widespread feline coronavirus. Vetstem LLC has developed a drug Ipecon® based on a low-molecular compound with a direct antiviral effect against RNA-containing viruses. Ipekon® has passed all preclinical studies. The purpose of the study: to evaluate the therapeutic efficacy of the veterinary drug Ipecon® in the treatment of feline infectious peritonitis. Materials and methods: the study included 28 cats, aged 6 months to 11 years: 18 animals with exudative and 8 with non-exudative («dry») form of IPK/FIP. The animals were divided into 3 groups, taking into account the starting single dose of the drug Ipecon®: 8 mg/kg, 10 mg/kg, 12 mg/kg. The finished solution was administered subcutaneously daily, once a day, with an interval between injections of 24 hours during the entire course of treatment. The assessment of the treatment effectiveness was comprehensive, taking into account the data of the clinical examination, the results of general clinical and biochemical blood tests, ultrasound of internal organs. Results: of the 28 animals with diagnosed IPC/FIP included in the study, 4 (14.3%) patients had a fatal outcome caused by multiple organ failure; 85.7 % of patients had the status of «clinical recovery» at the end of the course of treatment. Good tolerability of the drug Ipecon® has been established with repeated subcutaneous use. Despite the noted discomfort during administration, there were no signs of intoxication or clinically pronounced abnormalities, deterioration in the functions of organs and systems. During the use of the drug Ipecon®, only one case was noted.

Insights on feline infectious peritonitis risk factors and sampling strategies from polymerase chain reaction analysis of feline coronavirus in large-scale nationwide submissions.

This nationwide study aimed to investigate risk factors associated with FIP and determine optimal sample submission strategies for its diagnosis. A total of 14,035 clinical samples from cats across the US were analyzed by means of reverse transcriptase quantitative PCR to detect replicating feline coronavirus (FCoV). χ2 and logistic regression analyses were conducted to assess the association between FCoV detection rates and risk factors such as age, gender, breed, and types of submitted samples. Higher FCoV detection rates were observed in younger cats, particularly those aged 0 to 1 year, and in male cats. Purebred cats, notably British Shorthairs [OR: 2.81; P < .001], showed a higher incidence of FCoV infection than other cats. Peritoneal fluid (OR, 7.51; P < .001) exhibited higher FCoV detection rates than other samples, while lower rates were seen in blood samples (OR, 0.08; P < .001) than in other samples. High FCoV detection rates were found in urine, kidney, and lymph node samples. The study identified significant risk factors associated with FIP. Optimal sample submission strategies, particularly emphasizing the use of peritoneal fluid, kidney, and lymph node, were identified to improve FIP detection rates. Urine yielded a relatively high frequency of infection and viral loads compared with most other samples. Understanding the risk factors and optimizing sample selection for FIP diagnosis can aid in the early detection and management of the disease, ultimately improving outcomes for affected cats. These findings contribute valuable insights to FIP epidemiology and underscore the importance of continued research to enhance diagnostic strategies and disease management approaches.

Nested PCR effective to detect low viral loads of SARS-CoV-2 in animal samples

SARS-CoV-2 emerged from an animal source and was then transmitted to humans, causing the COVID-19 pandemic. Since a wide range of animals are susceptible to SARS-CoV-2 infection, the zoonotic potential of SARS-CoV-2 increases with every new animal infected. The molecular gold standard assay for SARS-CoV-2 detection is real-time RT-PCR, where the Ct obtained is proportional to the amount of nucleic acid and can be a semi-quantitative measure of the viral load. However, since the use of real-time RT-PCR assays in animal samples is low due to the high costs, the use of validated nested PCR assays will help to monitor large-scale animal samplings, by reducing the costs of detection. In the present study, 140 samples from dogs and cats (15 SARS-CoV-2-positive samples with Ct values from 27 to 33, and 125 negative samples), previously analyzed by real-time RT-PCR, were analyzed by nested PCR. To increase the number of positive samples to determine the sensitivity of the assay, 40 human samples obtained during COVID-19 diagnosis in 2020 were included. The specificity of the primers was analyzed against samples positive to canine coronavirus (CCV) and feline infectious peritonitis virus (FIPV). To calculate the limit of detection (LoD) of the nested PCR, the viral load was estimated extrapolating the Ct value obtained by real-time RT-PCR. The Ct values obtained were considered as semi-quantitative and were able to distinguish between high, moderate and low viral loads. The Kappa value or “agreement” between assays and reliability of the nested PCR were also determined. Eleven of the animal samples analyzed by nested PCR targeting the N gene were detected as positive, while 129 were detected as negative to the virus, with Ct values ranging between17 and 31.5. All the samples from humans analyzed by nested PCR were positive. These results indicate that the assay has a sensitivity of near 95 % and a specificity of 100 %. No unspecific reactions analyzed by nested PCR were observed with the samples positive to CCV and FIPV. The samples detected as positive to SARS-CoV-2 by nested PCR were those that presented a Ct between17 and 31.5. The LoD of the nested PCR was estimated close to 50 copies/µL of viral load, corresponding with a Ct of 31.5. The Kappa value between assays was excellent (k = 0.829). The results obtained demonstrate that nested PCR is useful to detect SARS-CoV-2 low viral loads at a lower cost than with real-time RT-PCR.

Phylogenetic Analysis of Alphacoronaviruses Based on 3c and M Gene Sequences Isolated from Cats with FIP in Romania.

Coronaviruses are widespread in mammals and birds, causing mostly digestive and respiratory problems. In cats, feline coronaviruses undergo mutations while replicating, giving rise to the fatal coronavirus causing the feline infectious peritonitis (FIP) disease. Several mutations in viral genes, among them 3c and M, are involved in the development of FIP. In order to study these viral shifts, samples of 43 organs, feces, and ascites collected from cats showing clinical signs of feline infectious peritonitis were tested, and the sequences obtained for the 3c and M genes were analyzed. The 3c gene nucleotides showed truncations commonly observed in feline infectious peritonitis virus. Additionally, the sequences corresponding to the 3c genes obtained from different organs of the same individual displayed high similarities, supporting the internal mutation theory. The analyses of the M gene and putative polypeptides showed similarities with canine coronaviruses, supporting the recombination theory between feline and canine coronaviruses. Infectious coronaviral strains are still challenging because of the difficulty in obtaining an effective vaccine for their prevention, and also because of the limited alternatives for therapy of FIP in cats.

Comparison of Antiviral Immune Responses in Healthy Cats Induced by Two Immune Therapeutics.

Effective immunotherapeutic agents for use in cats are needed to aid in the management of intractable viral diseases, including feline infectious peritonitis (FIP) infection. The objectives of this study were to compare two different immune stimulants for antiviral activity in cats: (1) TLR 2/6-activating compound polyprenyl immunostimulant; (PI) and (2) liposome Toll-like receptor 3/9 agonist complexes (LTCs) to determine relative abilities to stimulate the induction of type I (IFN-α, IFN-β) and type II (IFN-γ) interferon immune responses in vitro and to study the effects of treatment on immune responses in healthy cats. Cytokine and cellular immune responses to PI and LTC were evaluated using peripheral blood mononuclear cells (PBMCs) from healthy cats incubated with LTC and PI at indicated concentrations using reverse transcriptase polymerase chain reaction assays and ELISA assays. The effects of the immune stimulants on inhibiting FIPV replication were assessed using a feline macrophage cell line (fcwf-4). Cytokine and cellular immune responses to PI and LTC were evaluated in blood samples from healthy cats treated with PI and LTC, using reverse transcriptase polymerase chain reaction (RT-PCR) and ELISA assays. In the in vitro studies, both compounds triggered the upregulated expression of IFN-α, IFN-γ, and IL-1β genes in cat PBMC, whereas treatment with LTC induced significantly greater expression of IFN-α and IFN-γ on Day 1 and IL-1b on Day 3. There was significant protection from FIPV-induced cytopathic effects when fcwf-4 cells were treated with conditioned medium from LTC-activated leukocytes. In the healthy cat study (in vivo), both PI and LTC increased the mRNA signal for IFN-α, IFN-γ, and IL-1β above baseline at multiple time points with statistically greater increases in the LTC group on either Day 1 (IFN-α, IFN-γ) or Day 3 (IL-1β). In addition, RANTES increased over time in cats treated with the LTC. Both LTC and PI protocols induced immune-enhancing effects, suggesting a possible clinical use for the management of chronic infectious diseases like FIP. Activating the TLR 3 and 9 pathways (LTC) induced superior broad interferon production in vitro than the activation of the TLR 2 and 6 pathways (PI).

Causes of shelter cats mortality in the Czech Republic

Awareness of the causes of mortality in shelter cats can contribute to its effective reduction. The aim of this study was to investigate the causes of mortality in cat shelters in the Czech Republic, taking into account the age of the animals and their length of stay in the shelter facilities until natural death or euthanasia. A cooperation with two private no-kill shelters in the Czech Republic was established. The subject of the study were records of 3047 cats admitted to the selected shelters in the period from 2013 to 2023. A total of 357 (11.7 %) out of 3047 cats died or had to be euthanized in two monitored shelters. No significant difference (p > 0.05) in the cat mortality was found between the two shelters (11.5 % and 12 %). The median length of stay of cats in the shelter until death or euthanasia was 23 days. The highest mortality was recorded in the youngest cats (≤ 6 months). The most common causes of death or euthanasia of cats in both shelters were feline infectious peritonitis (21.6 %), panleukopenia (18.5 %) and upper and lower respiratory tract infections (17.5 %). Adult and older cats were significantly (p < 0.05) more prone to death due to renal failure and cancer than young animals and kittens. The results of the study contribute to the knowledge on the health of cat population in shelters in the Czech Republic and can serve as a basis for further work that will target mortality reduction strategies in at-risk categories.

Short Treatment of 42 Days with Oral GS-441524 Results in Equal Efficacy as the Recommended 84-Day Treatment in Cats Suffering from Feline Infectious Peritonitis with Effusion-A Prospective Randomized Controlled Study.

In the past, feline infectious peritonitis (FIP) caused by feline coronavirus (FCoV) was considered fatal. Today, highly efficient drugs, such as GS-441524, can lead to complete remission. The currently recommended treatment duration in the veterinary literature is 84 days. This prospective randomized controlled treatment study aimed to evaluate whether a shorter treatment duration of 42 days with oral GS-441524 obtained from a licensed pharmacy is equally effective compared to the 84-day regimen. Forty cats with FIP with effusion were prospectively included and randomized to receive 15 mg/kg of GS-441524 orally every 24h (q24h), for either 42 or 84 days. Cats were followed for 168 days after treatment initiation. With the exception of two cats that died during the treatment, 38 cats (19 in short, 19 in long treatment group) recovered with rapid improvement of clinical and laboratory parameters as well as a remarkable reduction in viral loads in blood and effusion. Orally administered GS-441524 given as a short treatment was highly effective in curing FIP without causing serious adverse effects. All cats that completed the short treatment course successfully were still in complete remission on day 168. Therefore, a shorter treatment duration of 42 days GS-441524 15 mg/kg can be considered equally effective.

Development of multiplex real-time PCR for simultaneous detection of SARS-CoV-2, CCoV, and FIPV.

Coronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), canine coronavirus (CCoV), and feline infectious peritonitis virus (FIPV), have the potential for interspecies transmission. These viruses can be present in complex environments where humans, dogs, and cats coexist, posing a significant threat to both human and animal safety. In this study, we developed a novel multiplex TaqMan-probe-based real-time PCR assay for the simultaneous detection and differentiation of SARS-CoV-2, CCoV, and FIPV. Specific primers and TaqMan fluorescent probes were designed based on the N region of SARS-CoV-2 and FIPV, as well as the S region of CCoV, which demonstrated a remarkable sensitivity and specificity toward the targeted viruses, as few as 21.83, 17.25 and 9.25 copies/μL for SARS-CoV-2, CCoV and FIPV, respectively. The standard curve constructed by the optimized method in our present study showed a high amplification efficiency within or near the optimal range of 91% to 116% and R(2) values were at least 0.95 for the abovementioned coronaviruses. A total of 91 samples, including six plasmid mixed mock samples, four virus fluid mixing simulated samples, and 81 clinical samples, were analyzed using this method. Results demonstrated strong agreement with conventional approaches. By enabling the simultaneous detection of three viruses, this method enhances testing efficiency while decreasing costs. Importantly, it provides a valuable tool for the prevalence and geographical distribution of suspected and co-infected animals, ultimately contributing to the advancement of both animal and public health.

Theoretical studies of phytochemicals with feline infectious peritonitis virus proteins: a search for novel antivirals

Feline Infectious Peritonitis Virus (FIPV) is a highly lethal pathogen affecting cats worldwide. Developing effective antiviral treatments is crucial for managing this disease. This study investigates the potential of flavonoids to act as antiviral agents and allosteric modulators against the FIPV spike protein using molecular docking simulations. Thirteen flavonoids were docked against the FIPV spike protein (PDB ID: 6JX7) in both ligand-free (cleaned) and ligand-bound (uncleaned) states to assess their binding affinities and potential allosteric effects. The docking results revealed that all tested flavonoids exhibited strong binding affinities, with docking scores ranging from -7.9 to -9.6 kcal/mol in the cleaned receptor state. Notably, Hesperidin, Morin, Hesperetin, and Quercetin maintained or even improved their binding affinities in the presence of native ligands, suggesting their potential as allosteric modulators. Comparative analysis of the binding modes in the cleaned and uncleaned receptor states further supports the allosteric modulator potential of Morin, Hesperetin, and Hesperidin. These findings highlight the promising role of flavonoids as antiviral agents and allosteric modulators targeting the FIPV spike protein. Further experimental validation and optimization of these compounds could lead to the development of effective treatments for feline infectious peritonitis. This study provides valuable insights into the application of flavonoids in the management of viral diseases and contributes to the ongoing efforts in antiviral drug discovery.

Owner experience and veterinary involvement with unlicensed GS-441524 treatment of feline infectious peritonitis: a prospective cohort study.

Feline Infectious Peritonitis (FIP) has historically been a fatal coronavirus disease in cats. In recent years, the therapeutic agent GS-441524, developed by Gilead Sciences, was found to be a successful treatment for FIP in most patients in clinical trials. However, this particular drug has remained stalled in the therapeutic pipeline, leaving patients and cat owners without a licensed medication. In the meantime, online social media platforms began to emerge, connecting cat owners with a community of citizen non-veterinary professionals sourcing unlicensed GS-441524. This study prospectively followed participants (N = 141) that successfully completed 12 weeks of treatment, capturing their treatment experiences with self-administered GS-441524-like medication. A one-time survey was administered to enrolled participants with mixed format of questions (open-ended and multiple-choice) asking about treatment administration techniques, observed side effects of GS-441524, accrued cost, veterinarian involvement, impact on the cat-human bond, and social media usage. Our results show cat owners experienced a shift in treatment modality from injectable GS-441524 to pill formulation across the treatment period. The average total cost of medication has decreased since 2021 to approximately USD 3100, and participants reported the human-animal bond being affected negatively. Additionally, there was an increased trend in veterinarian awareness of GS-441524-like therapeutics and monitoring of clients undergoing treatment. Social media usage was reported as being important at the beginning of treatment to establish treatment administration but lessened by the end of treatment. This study is the first detailed, prospective account of owner experiences with unlicensed GS-441524, raising an important discussion surrounding citizen veterinary medicine.