Carnivore protoparvovirus 1 | |
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Electron micrograph of canine parvovirus | |
Virus classification | |
(unranked): | Virus |
Realm: | Monodnaviria |
Kingdom: | Shotokuvirae |
Phylum: | Cossaviricota |
Class: | Quintoviricetes |
Order: | Piccovirales |
Family: | Parvoviridae |
Genus: | Protoparvovirus |
Species: | Carnivore protoparvovirus 1 |
Member virus [1] | |
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Carnivore protoparvovirus 1 is a species of parvovirus that infects carnivorans. It causes a highly contagious disease in both dogs and cats separately. The disease is generally divided into two major genogroups: FPV containing the classical feline panleukopenia virus (FPLV), and CPV-2 containing the canine parvovirus type 2 (CPV-2) which appeared in the 1970s. [2]
Belonging to the family Parvoviridae, FPLV have linear, single-stranded DNA (ssDNA) genomes. This agent is one of the smallest animal viruses, barely 18 to 20 nm in diameter. [3] Like other parvovirus genomes, it has hairpin structures at both ends of its genome: 3-genome Y-type structure and 5-terminal U-shaped structure, making it challenging to amplify the full-length genome of parvovirus despite its small size. [4] Sequences in the genome show a high degree of nucleotide conservation in the VP2 gene after over 90 years since it has emerged; the VP2 gene codes for the capsid protein VP2, a main structural protein, which determines the major mutations during the evolution of CPV. [5]
FPLV is known to infect all wild and domestic members of the felid (cat) family worldwide. [6] It is a highly contagious, severe infection that causes gastrointestinal, immune system, and nervous system disease. Its primary effect is to decrease the number of white blood cells, causing the disease known as feline panleukopenia.
Although it was once thought that only FPLV caused panleukopenia in cats, [7] it has been confirmed that a feline panleukopenia illness can be caused by CPV 2a, 2b, and 2c. [8] [9]
FPLV is commonly referred to as:
It is sometimes confusingly referred to as "cat plague" and "feline distemper". [11]
In addition to members of the felid family, it can also affect other carnivorans (e.g. raccoon, mink). [6]
Formed within English using elements derived from Greek: pan- a combining form meaning "universal" or "worldwide", -leuco- a combining form meaning (in biologic sciences) "white blood cell", and -penia a combining form meaning "loss of" or "decrease of". Thus the word means universal loss of white blood cells. The universal part refers to both its worldwide distribution and to the fact that all species of cats are infected. [12]
The feline panleukopenia virus is considered ubiquitous, meaning it is in virtually every place that is not regularly disinfected. The infection is highly contagious among unvaccinated cats. [13]
Antibodies against FPLV, produced by the adaptive immune system, play an important role in the feline response to the virus. Maternally-derived antibodies (MDA) efficiently protect kittens from fatal infection. This passively acquired immunity is later replaced by an active immune response obtained by vaccination or as a consequence of a natural infection. [14] In kittens, the period of greatest susceptibility to infection is when maternal antibodies are absent, or waning, and vaccine-induced immunity has not yet fully developed. [15]
Free-roaming cats are thought to be exposed to the virus during their first year of life. Those that develop a subclinical infection or survive acute illness mount a robust, long-lasting, protective immune response. [6]
An infected cat sheds large amounts of virus in all body secretions including feces, vomit, urine, saliva, and mucus during the acute phase of illness. It can continue to shed the virus for as long as six weeks after recovery. [6] Subclinically ill cats can also shed the virus in body secretions. The virus can be carried or transferred on an infected object (such as bedding, food dishes, fur) or by other animals, fleas, and humans (see: fomites). [16] It persists long after evidence of the original body secretion has faded away, and can be transported long distances. Like all parvoviruses, FPLV is extremely resistant to inactivation and can survive for longer than one year in a suitable environment. [17] Kitten deaths have been reported in households of fully vaccinated cats, possibly because of exposure to large amounts of virus in the environment. [11] [18] In a recent study, microRNA responses to FPLV infection were identified in feline kidney cells by sequencing, providing a possible link between miRNA expression and pathogenesis of FPV infection. [19]
Infection occurs when the virus enters the body through the mouth or nose. Whether illness results or not depends on the immunity in the victim vs. the number of individual virus particles (i.e. the amount of virus) entering the body. [13]
The clinical manifestations of FPLV are variable based on the dose of the virus, the age of the cat, potential breed predispositions, and prior immunity from maternal antibodies, previous exposure, or vaccination. [20] Most infections are subclinical, as evidenced by the high seroprevalence of anti-FPV antibodies among some populations of unvaccinated, healthy cats. The cats that become clinically ill are usually less than one year old, but older cats are also at risk. [21] There is high mortality in clinically affected kittens, and sudden death can occur. [20]
Clinical signs usually develop in 4–6 days after exposure, but can show in 2–14 days. [22] The virus infects and destroys actively dividing cells in bone marrow, lymphoid tissues, intestinal epithelium, and—in very young animals—in the cerebellum and retina. [6] The virus primarily attacks the lining of the gastrointestinal tract, causing internal ulceration and, ultimately, total sloughing of the intestinal epithelium.
Primary signs include:
Clinical laboratory findings include (but are not limited to): [15] [21]
Other signs include: fever, loss of skin elasticity due to dehydration, abdominal pain, sternal recumbency[ jargon ] with splayed legs and head droop, nasal discharge and conjunctivitis. [20] Cats may sit at a water bowl, but not drink. [6] Terminal cases are hypothermic and may develop septic shock and disseminated intravascular coagulation. [17]
Infection in pregnant cats can result in fetal resorption, mummification, abortion, or stillbirth of neonates. [6] Fetuses infected in utero that survive and kittens less than a few weeks of age that become infected can have cerebellar hypoplasia, retinal dysplasia, and optic neuropathy. [23] [ page needed ]
A presumptive clinical diagnosis of FPLV can be made for kittens with appropriate signalment, history, clinical findings and the history of no prior vaccination. [20]
The clinical diagnosis is usually supported by documenting parvovirus antigen in feces by ELISA (enzyme-linked immunosorbent assay) and PCR (polymerase chain reaction) assays. The availability of validated assays varies by country but is becoming more common. PCR assays are so sensitive that FPV DNA can be amplified from feces of cats vaccinated with modified live strains of the virus. Attenuated parvoviruses in MLV vaccines replicate in the blood and intestine, and post-vaccinal fecal shedding of FPV has been demonstrated, which can result in recent vaccinations giving false positive results on diagnostic tests. [24] At least one of the ELISA antigen tests for dogs (SNAP®Parvo; IDEXX Laboratories) detects FPV in feline feces and has a cut point for a positive test result that excludes most vaccinated cats. Thus, this ELISA is superior to PCR for screening cats for FPV infection and can also be performed in the veterinary clinic. (These are only approved and licensed for detecting canine parvovirus, but it is generally known that they also detect FPL viral antigen in feline feces. These tests are used extra-label because they allow rapid, inexpensive, in-house detection of the virus. [25] ) Positive fecal SNAP test results, including weak positives, are highly likely to be true positives in clinically affected animals. [26] Some cats will have completed the shedding period by the time the test is run, leading to false-negative results. [20] [25] [27] Electron microscopy, virus isolation and seroconversion can also be used to document active or recent infection.
Leukopenia on a complete blood count (nadir 50–3,000 WBC/μL) supports a diagnosis of FPLV. In an unvaccinated cat, the presence of antibodies against FPV indicates that the cat either has the disease or has had the disease in the past. Elevated IgM titers (1:10 or greater) indicate active infection and if clinical signs are obvious (diarrhea, panleukopenia) the prognosis is poor. Elevated IgG titers (1:100 or greater) in a cat with clinical signs indicates a better prognosis. [28]
Differential diagnoses include salmonellosis, enteric toxins, feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), cryptosporidiosis, pancreatitis, septicaemia with acute endotoxemia, toxoplasmosis, peritonitis, and lymphoma. [28]
To contain the virus, cats with suspected or diagnosed FPLV should be kept in isolation. [29]
It requires immediate, aggressive treatment if the cat is to survive, as it can be fatal in less than 24 hours. Several articles and publications provide guidance for rescuers and veterinarians for optimizing outcomes. [30] [29]
Treatment involves: [31]
Feeding should be continued as long as possible. [32] A highly digestible diet is preferred, but the individual animal's preferences may dictate giving whatever it will eat. [29] In anorexic, hypoproteinemic, vomiting and diarrheic cats parenteral nutrition is required. [30]
In a disease outbreak, unvaccinated kittens or adults can be given anti-FPV serum containing FPV antibodies injected subcutaneously or intraperitoneal. This may provide protection for 2–4 weeks. [33] [34] Therapeutic efficacy of anti-FPV serum has been demonstrated in dogs, [35] and similar beneficial effects may be expected in cats. [29]
Several studies have shown recombinant feline interferon omega is effective in the treatment of parvoviral enteritis in dogs [36] [37] and also inhibits replication of FPV in cell culture. So far no data are available on its efficacy in FPV-infected cats.
Cats typically die due to complications associated with sepsis, dehydration, and disseminated intravascular coagulopathy (DIC). [30] Leukocytopenia predisposes patients to secondary infections, especially bacterial and fungal, though secondary viral infections also occur.
It has been stated that cats with FPLV may be at risk for endocarditis or cardiomyopathy (since CPV-2 is a well-known cause of viral myocarditis in young puppies), but a 2017 retrospective study concluded that "Feline Panleukopenia Virus Is Not Associated With Myocarditis or Endomyocardial Restrictive Cardiomyopathy in Cats". [38]
Mortality in affected felid litters varies between 20 and 100%. [39] Mortality of FPLV is 25–90% in domestic cats with the acute form of the disease and up to 100% in cats with peracute disease. [30] [40]
In 2010, a retrospective study of 244 infected cats showed that "leukocyte and thrombocyte counts as well as serum albumin and potassium concentrations at presentation are prognostic indicators in cats with panleukopenia, whereas vaccination status, age, clinical signs, and housing conditions are not." [21]
A survival rate of about 50% has been reported with supportive therapies. [41] Cats with FPLV that survive the first five days of treatment usually recover; [27] however, the decrease in the cat's white blood cells compromises its immune system, leaving it vulnerable to secondary infection.[ citation needed ] Lifelong immunity is thought to follow recovery from disease, and a carrier state of the disease has never been identified. [15]
Cats with suspected or diagnosed FPLV should be kept in isolation. This non-enveloped virus is very resistant to environmental conditions and many disinfectants, is highly contagious, and rapidly accumulates in the environment due to high shedding of virus from affected animals. [42] Strict protocols for containment – with isolation, minimal handling, and disinfection of all potential sources of fomites – is warranted. Recovered cats can still shed the virus for up to six weeks [6] and can carry it on their body for prolonged periods.
The practice of recommending and giving vaccines on a fixed schedule with annual boosters has been widely discarded. Current recommendations are based on the philosophy of vaccinating each cat no more frequently than necessary. These recommendations take into account considerations for the efficacy and longevity of each specific vaccine; the exposure, risk, and need of different cat populations; and socioeconomic limitations. [43] [44] [45] [46]
Recommendations vary for:
The FPLV vaccination is considered a "core" (essential for health) vaccine and is recommended for all domestic cats. [43] [47] Even cats kept indoors can be infected from fomite transmission. [48]
Several types and brands of commercial FPLV vaccines are available to induce acquired immunity. These include:
Combination vaccines that protect against several common viruses, including FPLV, are also available.
Selection or use of a specific type/brand of a vaccine may vary depending on the overall risk of viral infection to the specific animal in its environment, along with considerations for the time it takes to confer protection, its overall efficacy, the animal's health, and the potential risks associated with MLV vs killed, adjuvanted vs nonadjuvanted, intranasal/ocular vs injection.
Modified-live FPLV vaccines are not recommended in pregnant queens, very young kittens, or cats with FIV or FeLV. [49] [43]
Kittens without maternally derived antibodies are especially vulnerable. FPLV vaccination can start as early as 4 weeks of age for kittens at high risk but are usually started at 6 weeks, then given every 3–4 weeks until 16 weeks of age. For cats older than 16 weeks, 2 doses, 3 to 4 weeks apart is generally recommended, followed by a 6-month to 1-year booster. [44] [43] Thereafter, a booster vaccination every 3 years is usually recommended; [50] [43] a blood titer test can be done to determine individual antibody levels for catering the timing of boosters.
Canine distemper virus (CDV) is a viral disease that affects a wide variety of mammal families, including domestic and wild species of dogs, coyotes, foxes, pandas, wolves, ferrets, skunks, raccoons, and felines, as well as pinnipeds, some primates, and a variety of other species. CDV does not affect humans.
Feline immunodeficiency virus (FIV) is a Lentivirus that affects cats worldwide, with 2.5% to 4.4% of felines being infected.
Feline leukemia virus (FeLV) is a retrovirus that infects cats. FeLV can be transmitted from infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal's immune system, the virus weakens the cat's immune system, which can lead to diseases which can be lethal. Because FeLV is cat-to-cat contagious, FeLV+ cats should only live with other FeLV+ cats.
Feline infectious peritonitis (FIP) is a common and aberrant immune response in cats to infection with feline coronavirus (FCoV).
Canine parvovirus is a contagious virus mainly affecting dogs and wolves. CPV is highly contagious and is spread from dog to dog by direct or indirect contact with their feces. Vaccines can prevent this infection, but mortality can reach 91% in untreated cases. Treatment often involves veterinary hospitalization. Canine parvovirus often infects other mammals including foxes, wolves, cats, and skunks. Felines (cats) are also susceptible to panleukopenia, a different strain of parvovirus.
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.
Infectious canine hepatitis (ICH) is an acute liver infection in dogs caused by Canine mastadenovirus A, formerly called Canine adenovirus 1 (CAV-1). Canine mastadenovirus A also causes disease in wolves, coyotes, and bears, and encephalitis in foxes. The virus is spread in the feces, urine, blood, saliva, and nasal discharge of infected dogs. It is contracted through the mouth or nose, where it replicates in the tonsils. The virus then infects the liver and kidneys. The incubation period is 4 to 9 days.
Canid alphaherpesvirus 1 (CaHV-1), formerly Canine herpesvirus (CHV), is a virus of the family Herpesviridae which most importantly causes a fatal hemorrhagic disease in puppies less than two to three weeks old. It is known to exist in the United States, Canada, Australia, Japan, England and Germany. CHV was first recognized in the mid-1960s from a fatal disease in puppies.
Porcine parvovirus (PPV), a virus in the species Ungulate protoparvovirus 1 of genus Protoparvovirus in the virus family Parvoviridae, causes reproductive failure of swine characterized by embryonic and fetal infection and death, usually in the absence of outward maternal clinical signs. The disease develops mainly when seronegative dams are exposed oronasally to the virus anytime during about the first half of gestation, and conceptuses are subsequently infected transplacentally before they become immunocompetent. There is no definitive evidence that infection of swine other than during gestation is of any clinical or economic significance. The virus is ubiquitous among swine throughout the world and is enzootic in most herds that have been tested. Diagnostic surveys have indicated that PPV is the major infectious cause of embryonic and fetal death. In addition to its direct causal role in reproductive failure, PPV can potentiate the effects of porcine circovirus type II (PCV2) infection in the clinical course of postweaning multisystemic wasting syndrome (PMWS).
Bovine alphaherpesvirus 1 (BoHV-1) is a virus of the family Herpesviridae and the subfamily Alphaherpesvirinae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis. BoHV-1 is also a contributing factor in shipping fever, also known as bovine respiratory disease (BRD). It is spread horizontally through sexual contact, artificial insemination, and aerosol transmission and it may also be transmitted vertically across the placenta. BoHV-1 can cause both clinical and subclinical infections, depending on the virulence of the strain. Although these symptoms are mainly non-life-threatening it is an economically important disease as infection may cause a drop in production and affect trade restrictions. Like other herpesviruses, BoHV-1 causes a lifelong latent infection and sporadic shedding of the virus. The sciatic nerve and trigeminal nerve are the sites of latency. A reactivated latent carrier is normally the source of infection in a herd. The clinical signs displayed are dependent on the virulence of the strain. There is a vaccine available which reduces the severity and incidence of disease. Some countries in Europe have successfully eradicated the disease by applying a strict culling policy.
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.
Feline calicivirus (FCV) is a virus of the family Caliciviridae that causes disease in cats. It is one of the two important viral causes of respiratory infection in cats, the other being Felid alphaherpesvirus 1. FCV can be isolated from about 50% of cats with upper respiratory infections. Cheetahs are the other species of the family Felidae known to become infected naturally.
A vaccine-associated sarcoma (VAS) or feline injection-site sarcoma (FISS) is a type of malignant tumor found in cats which has been linked to certain vaccines. VAS has become a concern for veterinarians and cat owners alike and has resulted in changes in recommended vaccine protocols. These sarcomas have been most commonly associated with rabies and feline leukemia virus vaccines, but other vaccines and injected medications have also been implicated.
Vaccination of dogs is the practice of animal vaccination applied to dogs. Programs in this field have contributed both to the health of dogs and to the public health. In countries where routine rabies vaccination of dogs is practiced, for example, rabies in humans is reduced to a very rare event.
Animal viruses are viruses that infect animals. Viruses infect all cellular life and although viruses infect every animal, plant, fungus and protist species, each has its own specific range of viruses that often infect only that species.
The health of domestic cats is a well studied area in veterinary medicine.
Feline vaccination is animal vaccination applied to cats. Vaccination plays a vital role in protecting cats from infectious diseases, some of which are potentially fatal. They can be exposed to these diseases from their environment, other pets, or even humans.
Mink enteritis virus (MEV) is a strain of Carnivore protoparvovirus 1 that infects mink and causes enteritis. Like all parvoviruses, it is a small, spherical virus, and has a single-stranded DNA genome. The signs and symptoms of enteritis usually appear within 4–7 days after infection. The virus replicates in the cells of the crypt epithelium in the duodenum and jejunum and, to a lesser extent the ileum, colon and caecum. The severity of the disease is directly related to necrosis of the crypt epithelium.
Protoparvovirus is a genus of viruses in the Parvovirinae subfamily of the virus family Parvoviridae. Vertebrates serve as natural hosts. There are 15 species in the genus including Rodent protoparvovirus 1 for which the exemplar virus is minute virus of mice (MVM). This genus also includes canine parvovirus (CPV), which causes gastrointestinal tract damage in puppies that is about 80% fatal, and porcine parvovirus (PPV), which is a major cause of fetal death and infertility in pigs. The genus divides phylogenetically into two branches, one that contains many founder members of the family, such as MVM, CPV and PPV, which have been studied in considerable detail, and a second branch occupied exclusively by predicted viruses whose coding sequences were identified recently in the wild using virus discovery approaches, but whose biology remains minimally explored. This second branch currently contains two species whose members infect humans, called Primate protoparvovirus 1 and Primate protoparvovirus 3. Until 2014, the genus was called Parvovirus, but it was renamed to eliminate confusion between members of this genus and members of the entire family Parvoviridae.
Member species Species Virus name(s) Carnivore protoparvovirus 1 canine parvovirus CPV[ dead link ]