Felid alphaherpesvirus 1 | |
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Virus classification | |
(unranked): | Virus |
Realm: | Duplodnaviria |
Kingdom: | Heunggongvirae |
Phylum: | Peploviricota |
Class: | Herviviricetes |
Order: | Herpesvirales |
Family: | Orthoherpesviridae |
Genus: | Varicellovirus |
Species: | Felid alphaherpesvirus 1 |
Synonyms | |
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, [3] FVR is the most important of these diseases and is found worldwide. The other important cause of feline respiratory disease is feline calicivirus .
FVR is very contagious and can cause severe disease, including death from pneumonia in young kittens. It may cause flat-chested kitten syndrome, but most evidence for this is anecdotal. All members of the family Felidae are susceptible to FVR; in fact, FHV-1 has caused a fatal encephalitis in lions in Germany. [4]
FHV-1 was first isolated from cats in 1958 in the United States. [5]
FVR is transmitted through direct contact only. [6] It replicates in the nasal and nasopharyngeal tissues and the tonsils. Viremia (the presence of the virus in the blood) is rare. The virus is shed in saliva and eye and nasal secretions, and can also be spread by fomites. FVR has a two- to five-day incubation period. [3] The virus is shed for one to three weeks postinfection. [4] Latently infected cats (carriers) will shed FHV-1 intermittently for life, with the virus persisting within the trigeminal ganglion. Stress and use of corticosteroids precipitate shedding. Most disinfectants, antiseptics and detergents are effective against the virus. [6]
Initial signs of FVR include coughing, sneezing, nasal discharge, conjunctivitis, and sometimes fever (up to 106) and loss of appetite. These usually resolve within four to seven days, but secondary bacterial infections can cause the persistence of clinical signs for weeks. [4] Frontal sinusitis and empyema can also result.
FHV-1 also has a predilection for corneal epithelium, resulting in corneal ulcers, often pinpoint or dendritic in shape. Other ocular signs of FHV-1 infection include conjunctivitis, keratitis, keratoconjunctivitis sicca (decreased tear production), and corneal sequestra. [7] Infection of the nasolacrimal duct can result in chronic epiphora (excess tearing). Ulcerative skin disease can also result from FHV-1 infection. [8] FHV-1 can also cause abortion in pregnant queens, usually at the sixth week of gestation, [3] although this may be due to systemic effects of the infection rather than the virus directly.
In chronic nasal and sinus disease of cats, FHV-1 may play more of an initiating role than an ongoing cause. Infection at an early age may permanently damage nasal and sinus tissue, causing a disruption of ciliary clearance of mucus and bacteria, and predispose these cats to chronic bacterial infections. [9]
Diagnosis of FVR is usually by clinical signs, especially corneal ulceration. Definitive diagnosis can be done by direct immunofluorescence or virus isolation. However, many healthy cats are subclinical carriers of feline herpes virus, so a positive test for FHV-1 does not necessarily indicate that signs of an upper respiratory tract infection are due to FVR. Early in the course of the disease, histological analysis of cells from the tonsils, nasal tissue, or nictitating membrane (third eyelid) may show inclusion bodies (a collection of viral particles) within the nucleus of infected cells. [10]
Polyprenyl immunostimulant is the only currently-approved treatment in the US for feline rhinotracheitis caused by herpesvirus. [11] Effectiveness was demonstrated in a clinical study with cats experimentally infected with feline herpesvirus: 20 cats were treated with polyprenyl immunostimulant and 20 received a placebo. The study established that the severity of the disease was lower in the group treated with polyprenyl. [12] Safety was demonstrated in 390 personally-owned cats from 2 days to 16 years of age, residing in 10 states. [12]
Antibiotics are commonly used to prevent secondary bacterial infection. There are no specific antiviral drugs in common use at this time for FVR, although one study has shown that ganciclovir, PMEDAP, and cidofovir hold promise for treatment. [13] More recent research has indicated that systemic famciclovir is effective at treating this infection in cats without the side effects reported with other anti-viral agents. [14] More severe cases may require supportive care such as intravenous fluid therapy, oxygen therapy, or even a feeding tube. Conjunctivitis and corneal ulcers are treated with topical antibiotics for secondary bacterial infection. Lysine is commonly used as a treatment; however, in a 2015 systematic review, the authors investigated all clinical trials with cats as well as in vitro studies and concluded that lysine supplementation is likely not effective for the treatment or prevention of feline herpesvirus 1 infection. [15]
There is a vaccine for FHV-1 available (ATCvet code: QI06AA08 ( WHO ), plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. [16] Studies have shown a duration of immunity of this vaccine to be at least three years. [17] The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease. [18] The combination vaccine, Purevax RC, against feline viral rhinotracheitis and feline calicivirus was authorised for medical use in the European Union in February 2005. [19] [20]
Most household disinfectants will inactivate FHV-1. The virus can survive up to 18 hours in a damp environment, but less in a dry environment and only shortly as an aerosol. [16]
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.
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.
Pneumonia is an irritation of the lungs caused by different sources. It is characterized by an inflammation of the deep lung tissues and the bronchi. Pneumonia can be acute or chronic. This life-threatening illness is more common in cats than in dogs and the complication “Kennel Cough” can occur in young pets.
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.
Herpesviridae is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ἕρπειν, referring to spreading cutaneous lesions, usually involving blisters, seen in flares of herpes simplex 1, herpes simplex 2 and herpes zoster (shingles). In 1971, the International Committee on the Taxonomy of Viruses (ICTV) established Herpesvirus as a genus with 23 viruses among four groups. As of 2020, 115 species are recognized, all but one of which are in one of the three subfamilies. Herpesviruses can cause both latent and lytic infections.
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.
Aujeszky's disease, usually called pseudorabies in the United States, is a viral disease in swine that is endemic in most parts of the world. It is caused by Suid herpesvirus 1 (SuHV-1). Aujeszky's disease is considered to be the most economically important viral disease of swine in areas where classical swine fever has been eradicated. Other mammals, such as cattle, sheep, goats, cats, dogs, and raccoons, are also susceptible. The disease is usually fatal in these animal species.
Equid alphaherpesvirus 4, formerly Equine herpesvirus 4 (EHV-4) is a virus of the family Herpesviridae that cause rhinopneumonitis in horses. It is the most important viral cause of respiratory infection in foals. Like other herpes viruses, EHV-4 causes a lifelong latent infection in affected animals. These horses are usually the source for new infection for foals over two months old, weanlings, and yearlings. Symptoms include fever, loss of appetite, and discharge from the nose. Most infected animals recover in one to three weeks, but death can occur in environments with overcrowding and other stress factors. There are several vaccines available.
Equid alphaherpesvirus 1, formerly Equine herpesvirus 1 (EHV-1), is a virus of the family Herpesviridae that causes abortion, respiratory disease and occasionally neonatal mortality in horses. Initial spread of EHV-1 by a newly introduced horse through direct and indirect contact can lead to abortion and perinatal infection in up to 70 percent of a previously unexposed herd. Abortion usually occurs in the last four months of gestation, two to four weeks after infection of the mare. Perinatal infection can lead to pneumonia and death. Encephalitis can occur in affected animals, leading to ataxia, paralysis, and death. There is a vaccine available, however its efficacy is questionable. The virus varies in severity from sub-clinical to very severe. Most horses have been infected with EHV-1, but the virus can become latent and persist without ever causing signs of infection. In 2006, an outbreak of EHV-1 among stables in Florida resulted in the institution of quarantine measures. The outbreak was determined to have originated in horses imported from Europe via New York, before being shipped to Florida.
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.
Duck plague is a worldwide disease caused by Anatid alphaherpesvirus 1 (AnHV-1) of the family Herpesviridae that causes acute disease with high mortality rates in flocks of ducks, geese, and swans. It is spread both vertically and horizontally—through contaminated water and direct contact. Migratory waterfowl are a major factor in the spread of this disease as they are often asymptomatic carriers of disease. The incubation period is three to seven days. Birds as young as one week old can be infected. DEV is not zoonotic.
Bovine malignant catarrhal fever (BMCF) is a fatal lymphoproliferative disease caused by a group of ruminant gamma herpes viruses including Alcelaphine gammaherpesvirus 1 (AlHV-1) and Ovine gammaherpesvirus 2 (OvHV-2) These viruses cause unapparent infection in their reservoir hosts, but are usually fatal in cattle and other ungulates such as deer, antelope, and buffalo. In Southern Africa the disease is known as snotsiekte, from the Afrikaans.
Cat flu is the common name for a feline upper respiratory disease, which can be caused by one or more possible pathogens:
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.
Salmonid herpesvirus 3 (SalHV-3) is a species of virus in the genus Salmonivirus, family Alloherpesviridae, and order Herpesvirales.
Feline corneal sequestrum is the development of dark areas of dead tissue in the cornea of domestic cats. This disease is painful to the cat, although it develops slowly over a longer period of time. Cats will usually demonstrate teary eye(s), squinting or closing of the eye(s), and covering of the third eyelid.
Recombinant feline interferon omega (RFeIFN-ω), sold under the brand name Virbagen Omega among others, is a recombinant version of a cat interferon alpha. It is used to treat a range of viral diseases in cats and dogs, including canine parvovirus, feline leukemia virus (FeLV), and feline immunodeficiency virus (FIV) in many countries. It is approved to be used by injection under the skin. RFeIFN-ω is produced in silkworm larvae using a baculovirus vector.
Felid herpesvirus 1 Felid herpesvirus 1 [FJ478159=NC_013590] (FeHV-1) (Feline rhinotracheitis virus)