Feline infectious peritonitis | |
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FIP-infected kidney showing inflammatory response | |
Specialty | Infectious diseases |
Symptoms | Initial phase: common cold-like symptoms. Later on: ataxia, muscle weakness, dysphagia. End phase: shortness of breath, urinary incontinence, paralysis. |
Usual onset | Can take up to a year for symptoms to appear after exposure to virus |
Duration | 1-month or less average life expectancy after diagnosis, especially in kittens |
Causes | Mutation of feline coronavirus |
Treatment | UK, Australia, Netherlands: GS-441524 (given orally as tablets) and its parent drug remdesivir (given by intravenous or subcutaneous injection) [1] [2] [3] [4] |
Prognosis | Usually fatal without treatment, but with GS-441524 treatment over 80% of treated cats make a full recovery. |
Frequency | Common |
Feline infectious peritonitis (FIP) is a common and aberrant immune response in cats to infection with feline coronavirus (FCoV). [5]
FCoV is a virus of the gastrointestinal tract. Most infections are either asymptomatic or cause diarrhea, especially in kittens, as maternally derived antibody wanes at between 5 and 7 weeks of age. The virus is a mutation of feline enteric coronavirus (FECV). From the gut, the virus very briefly undergoes a systemic phase, [6] before returning to the gut where it is shed in the feces.
The pathogenesis of FIP is complex. There is a general consensus that FIPVs arise from mutations enabling them to enter or replicate more successfully in monocytes (a type of white blood cell). However, many aspects of virus–host interactions affecting the disease remain uncertain, such as the factors that influence disease form (wet or dry), outcome (death or resistance), and host susceptibility. [7]
There is a lack of evidence that FIP as such is transmissible from cat to cat, although it may explain rare mini-outbreaks of FIP. [8] However, the virus, FCov, is transmissible from cat to cat.
A study on 59 FIP infected cats found that, unlike FCoV, feces from FIP infected cats were not infectious to laboratory cats via oronasal route. [9] FCoV is common in places where large groups of cats are housed together indoors (such as breeding catteries, animal shelters, etc.). The virus is shed in feces, and cats become infected by ingesting or inhaling the virus, usually by sharing cat litter trays, or by the use of contaminated litter scoops or brushes transmitting infected microscopic cat litter particles to uninfected kittens and cats. [10] FCoV can also be transmitted through different bodily fluids. The virus is easily spread through direct contact between cats. The most common form of spreading is through saliva, as most multiple cat homes share food and water dishes. [11] Another major form of spreading is grooming or fighting. When an infected cat grooms a healthy cat, it leaves its contaminated saliva on the fur. Later, when the healthy cat goes to groom themselves, it ingests the contaminated saliva and then becomes infected. [12]
There are two main forms of FIP: effusive (wet) and non-effusive (dry). While both types are fatal, the effusive form is more common (60–70% of all cases) and progresses more rapidly than the non-effusive form.[ citation needed ]
The hallmark clinical sign of effusive FIP is the accumulation of fluid within the abdomen or chest, which can cause breathing difficulties. Other symptoms include lack of appetite, fever, weight loss, jaundice, and diarrhea.[ citation needed ]
Dry FIP will also present with lack of appetite, fever, jaundice, diarrhea, and weight loss, but there will not be an accumulation of fluid. Typically a cat with dry FIP will show ocular or neurological signs. For example, the cat may develop difficulty in standing up or walking, becoming functionally paralyzed over time. Loss of vision is another possible outcome of the disease.[ citation needed ]
Diagnosis of the effusive form of the disease has become more straightforward in recent years. Detection of viral RNA in a sample of the effusion (liquid drained from body), such as by reverse transcription polymerase chain reaction (RT-PCR) is diagnostic of effusive FIP. [13] [14] [15] However, that does require that a sample be sent to an external veterinary laboratory. Within the veterinary hospital there are a number of tests which can rule out a diagnosis of effusive FIP within minutes:
Non-effusive FIP is more difficult to diagnose than effusive FIP because the clinical signs tend to be more vague and varied: the list of differential diagnoses is therefore much longer. Non-effusive FIP diagnosis should be considered when the following criteria are met: [16]
Non-effusive FIP can be ruled out as a diagnosis if the cat is seronegative, provided the antibody test has excellent sensitivity. In a study which compared various commercially available in-house FCoV antibody tests, [19] the FCoV Immunocomb (Biogal) was 100% sensitive; the Speed F-Corona rapid immunochromatographic (RIM) test (Virbac) was 92.4% sensitive and the FASTest feline infectious peritonitis (MegaCor Diagnostik) RIM test was 84.6% sensitive.
Because FIP is an immune-mediated disease, treatment falls into two categories: direct action against the virus itself and modulation of the immune response.
Antivirals (in the narrow sense) act by interfering with the enzymes or other biological processes in the FIP virus.
An experimental drug called GS-441524 was used in a field experiment of 31 cats. After 25 days, five cats had died, eight had been cured and subsequently relapsed, and 18 had been cured without any subsequent relapses. The eight who relapsed were treated again, some with higher doses. Of these eight, one died and seven were cured, meaning that 25 of the 31 cats were ultimately cured of FIP. Although the drug is not yet (as of 2024) commercially available in the United States, the FDA allows its usage under certain conditions. [20] This study is considered very promising and may lead to commercially available medication for the treatment of FIP. [21]
In several countries oral GS-441524 tablets (and its injectable prodrug remdesivir) became legally available to vets for the treatment of FIP in cats, for example in Australia, [22] the Netherlands, [23] [lower-alpha 1] and the United Kingdom (since August 2021). [22] In naturally infected cats, a recovery rate of over 80% has been observed with GS-441524 treatment in several studies and in treatment programs in countries where the drug is legalised. [22] [25] [26] [27]
An experimental antiviral drug called GC376 was used in a field trial of 20 cats: seven cats went into remission, and 13 cats responded initially but relapsed and were euthanized. This drug is not yet (as of 2017) commercially available. [28]
Facing a high-fatality FCoV-23 outbreak on the island nation of Cyprus, on 8 August 2023 the government released 80,000 anti-COVID molnupiravir pills from its national COVID-19 stockpile, in a bid to solve the feline coronavirus crisis in a more cost-effective manner. [29]
Immunostimulants are drugs that make the immune system more active against the virus. The most common drugs of this class for treating FIP are either recombinant feline interferon omega (Virbagen Omega, Virbac) or human interferon alfa-2b. Since the human version ends up being targeted by the immune system for being a foreign antigen, the feline version feline interferon is more effective. [30]
An experimental polyprenyl immunostimulant (PI) is manufactured by Sass and Sass and tested by Dr. Al Legendre, who described survival over 1 year in three cats diagnosed with FIP and treated with the medicine. [31] In a subsequent field study of 60 cats with non-effusive FIP treated with PI, 52 cats (87%) died before 200 days, but eight cats survived over 200 days from the start of PI treatment for and four of those survived beyond 300 days. [32]
It is recommended to use an anti-inflammatory drug against FIP. [33]
Immunosuppressive drugs dampen the immune system, helping to reduce inflammation. The go-to immunosuppressive drug in FIP is prednisolone, a corticosteroid. There are no placebo-controlled trials showing prednisolone to be better than other anti-inflammatories. [33]
There is no effective vaccine against FIPV. DNA vaccination with plasmids encoding FIPV proteins failed to produce immunity. [34] Rather, it was observed that antibodies to the FIPV spike protein exacerbate the disease.
A 2018 film titled Aeris, by Paul Castro Jr. and Aly Miller, and starring Frank Deal, Arabella Oz and Betsy Aidem, is about a kitten born with FIP that is purchased from a pet store and the owners' twelve days with it. [35] [36] The film received an award at the 2018 Garden State Film Festival in the Narrative Short category [37] and was a Gold Kahuna winner at the 2018 Honolulu Film Awards. [38]
Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the common cold, while more lethal varieties can cause SARS, MERS and COVID-19. In cows and pigs they cause diarrhea, while in mice they cause hepatitis and encephalomyelitis.
Feline immunodeficiency virus (FIV) is a Lentivirus that affects cats worldwide, with 2.5% to 4.4% of felines being infected.
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An opportunistic infection is an infection caused by pathogens that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune system, an altered microbiome, or breached integumentary barriers. Many of these pathogens do not necessarily cause disease in a healthy host that has a non-compromised immune system, and can, in some cases, act as commensals until the balance of the immune system is disrupted. Opportunistic infections can also be attributed to pathogens which cause mild illness in healthy individuals but lead to more serious illness when given the opportunity to take advantage of an immunocompromised host.
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Cerebellar hypoplasia (CH) is a neurological condition in which the cerebellum is smaller than usual or not completely developed. It has been reported in many animal species.
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Feline viral rhinotracheitis (FVR) is an upper respiratory or pulmonary infection of cats caused by Felid alphaherpesvirus 1 (FeHV-1), of the family Herpesviridae. It is also commonly referred to as feline influenza, feline coryza, and feline pneumonia but, as these terms describe other very distinct collections of respiratory symptoms, they are misnomers for the condition. Viral respiratory diseases in cats can be serious, especially in catteries and kennels. Causing one-half of the respiratory diseases in cats, FVR is the most important of these diseases and is found worldwide. The other important cause of feline respiratory disease is feline calicivirus.
The health of domestic cats is a well studied area in veterinary medicine.
Feline coronavirus (FCoV) is a positive-stranded RNA virus that infects cats worldwide. It is a coronavirus of the species Alphacoronavirus 1, which includes canine coronavirus (CCoV) and porcine transmissible gastroenteritis coronavirus (TGEV). FCoV has two different forms: feline enteric coronavirus (FECV), which infects the intestines, and feline infectious peritonitis virus (FIPV), which causes the disease feline infectious peritonitis (FIP).
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GC376 is a broad-spectrum antiviral medication under development by the biopharmaceutical company Anivive Lifesciences for therapeutic uses in humans and animals. Anivive licensed the exclusive worldwide patent rights to GC376 from Kansas State University. As of 2020, GC376 is being investigated as a treatment for COVID-19. GC376 shows activity against many human and animal viruses, including coronavirus and norovirus; the most extensive research has been multiple in vivo studies in cats treating a coronavirus, which causes deadly feline infectious peritonitis. Other research supports use in porcine epidemic diarrhea virus.
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GS-441524 is a nucleoside analogue antiviral drug which was developed by Gilead Sciences. It is the main plasma metabolite of the antiviral prodrug remdesivir, and has a half-life of around 24 hours in human patients. Remdesivir and GS-441524 were both found to be effective in vitro against feline coronavirus strains responsible for feline infectious peritonitis (FIP), a lethal systemic disease affecting domestic cats. Remdesivir was never tested in cats, but GS-441524 has been found to be effective treatment for FIP.
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