Rhinotracheitis, or herpes virus infection in Maine Coon and other felines

7 August 2022

Herpesvirus infection of cats, or rhinotracheitis (FHV) is a disease caused by the herpes virus.
Rhinotracheitis is a widespread respiratory disease of cats and unfortunately our Maine Coons are no exception. The disease caused by the herpes virus of cats type 1. The disease is species-specific and does not pose a threat to other animal species and humans. It proceeds in an acute and chronic form.

Source of infection:

sick animals with an acute form of infection/
carrier cats that have been ill: they are latent, i.e. without symptoms of the disease, carriers of the virus in nerve cells, especially the trigeminal nerve, the duration of the carrier is on average 6 months, but can be lifelong.
cats with a chronic form of infection in the acute stage.

Infection with the virus occurs through secretions from the nose, mouth, eyes of sick animals: through direct contact with a sick cat, through infected air, care items, feed, as well as through shoes and clothing of people who have come into contact with the source of infection. The introduction and reproduction of the virus (replication) in the cat’s body occurs mainly in the mucous membranes of the nasopharynx and tonsils, but in addition, the conjunctiva of the eyes, lymph nodes, etc. are often included in the pathological process.; infection of unvaccinated pregnant cats leads to intrauterine infection of fetuses (and as a consequence – abortions, the birth of dead or non-viable fetuses).
The release of the virus into the environment begins 24 hours after infection and lasts up to 3 weeks. Virus resistance: the virus dies at 37C within 3 hours, at 56C – within 5 minutes; remains viable at 25C for 1 month, at 4C -5 months. It is sensitive to most disinfectants and antiseptics.
The herpes virus of cats leads, as a rule, to an acute respiratory disease. The incubation (latent) period of the disease is usually 2-6 days.

Clinical signs of the disease:

Depression and lack of appetite.
Sneezing and discharge from the nose and eyes, at first transparent (serous), and with a prolonged course of the disease become mucopurulent.
An increase in body temperature.
There may be a cough, shortness of breath.
Sometimes ulcers of the tongue appear, which clinically resembles another infectious disease of cats – calcivirosis. Most often, this symptom is observed in cats with a chronic course of herpes in the acute stage.
Corneal lesions: ulcers and deep keratitis.
There may be salivation (usually observed with ulcers in the oral cavity).
Very rarely – ulcers on the nose, the skin of the muzzle.
Rhinotracheitis often occurs together with other infections: chlamydia, calcivirosis, mycoplasmosis, Bordetella bronchoseptica (Bordetella bronchiseptica).

Despite the fact that this disease can lead to a serious condition, the mortality rate is low, with the exception of very small kittens and cats with severely weakened immunity. Death is most often due to dehydration, a secondary bacterial infection leading to bronchopneumonia. On average, the symptoms of the disease are observed for 7-10 days.


After recovering from acute herpesvirus infection, about 80% of cats remain virus carriers (i.e. they look completely healthy externally) and about 50% of them release the virus into the environment. Virus release can occur spontaneously, but mostly it happens after stress: moving to another place of residence, visiting exhibitions, childbirth, lactation, the use of glucorticosteroids (for example, prednisone, dexamethasone), surgical interventions, etc.
Cats can become virus carriers even without showing any symptoms, i.e. a cat, having become infected, may turn out to be a carrier even though she herself has never shown signs of the disease or has been fully vaccinated.
Also, rhinotracheitis is characterized by a transition to a chronic (latent, or latent) form: in this case, the virus enters the environment only during the period of exacerbation, i.e. when symptoms of the disease appear. Chronic (latent) herpesvirus infection most often passes into the acute stage due to stress: relocation, exhibitions, surgical interventions, etc.


Despite the fact that Maine Coons and other cats have other infections accompanied by respiratory symptoms (such as calcivirosis, chlamydia, etc.), in most cases, the available clinical signs are sufficient for diagnosis.
For diagnosis in Russia, the PCR method is most often used, for this purpose, smears from the nose and conjunctiva of the eyes are taken. With primary herpersvirus infection, the virus is detected for a maximum of 7 days from the onset of clinical manifestations, with repeated infection – for a maximum of 4 days, during the latent phase, the virus is not detected in conventional smears from the conjunctiva, because it is no longer there, but it is localized in the cells of the nervous tissue.


Many sick cats do not eat, because they lose their sense of smell or because of soreness caused by the presence of ulcers in the oral cavity, so it is very important to feed the cat: for this purpose, any ready-made food in the form of pate, which is pre-diluted with warm water, and given to the cat from a syringe for 10-20 ml without a needle, is suitable. If the cat cannot be force-fed for 3 days, she is shown the installation of special probes through which feeding will be carried out.
Nasal flushing with 0.9% sodium chloride solution (saline solution) to cleanse accumulated secretions is carried out daily and several times a day. A sick cat should be kept in a clean, well-ventilated room.
Antibiotics for the treatment of secondary bacterial infection
Systemic antiviral drugs
Symptomatic treatment: intravenous droppers are necessary for cats with severe symptoms of dehydration, antipyretics are used at elevated temperatures, etc.

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