QUARTERLY BEAT / DECEMBER 2023 ///
/// QUARTERLY BEAT / DECEMBER 2023
FELINE UPPER RESPIRATORY DISEASE The Sneezing Cat: SNEEZING, ULCER, INFECTION?…OH MY!
be reactivated due to stress, illness, or immunosuppression and can result in intermittent reactivation and shedding of the virus, which can also occur in the absence of clinical signs in cases of chronic, latent FHV infection. Both FCV and FHV-1 are mainly transmitted from cat to cat but can also be transmitted in the environment and on fomites. FHV-1 is susceptible to common disinfectants, but FCV can persist in the environment for about a month and is resistant to many common disinfectants; bleach is the preferred agent for killing the virus. Cats with URT signs should be isolated and strict hygiene practices should be followed. FCV and FHV-1 can best be detected by polymerase chain reaction (PCR) in conjunctival and oropharyngeal swabs. Caution should be taken when interpreting any FCV RT-PCR- positive result because of the poor correlation between the presence of viral RNA and clinical signs; a negative result does not rule out FCV infection and healthy cats can test positive. All cats should be vaccinated against FCV and FHV-1 (core vaccine). Vaccination usually protects from disease but not from infection. Considering the high genetic variability of FCV, changing to different vaccine strain(s) may be of benefit if significant disease occurs or recurs in fully vaccinated cats. Vaccination protocols for cats in multi-cat environments should adopt yearly schedules as per the AAFP vaccination guidelines. Infection-induced immunity is not life-long and does not protect against all strains, therefore vaccination of cats that have recovered from caliciviral disease is also recommended.
BACTERIAL INFECTIONS The main bacterial pathogens in cats causing URT include Chlamydia psittaci, Mycoplasma felis, and Bordetella bronchiseptica. Although these can be primary pathogens, they are more commonly secondary to and concurrent with viral infection. Viral agents damage the respiratory epithelium, making cats (especially young cats) more susceptible to opportunistic pathogens, such as staphylococci, streptococci, and other bacterial pathogens. Most cats with mucopurulent nasal discharge maintain normal appetite and attitude and experience spontaneous resolution of illness within 10 days without antimicrobial treatment. The ISCAID Working Group recommends that antimicrobial treatment be considered within the 10-day observation period only if fever, lethargy, or anorexia is present concurrently with mucopurulent nasal discharge. A more extensive diagnostic workup should be considered for cats with URTD of >10 days of duration, particularly in the face of therapeutic failure after treatment of suspected acute bacterial URI.
DR. PETRA CERNA , MRCVS, AFHEA, AdvCertFB
Colorado State University
Sneezing, ulcer, infection?...Oh my! MVDr. Petra Cerna, PhD, MRCVS, CertAVP, AFHEA, AdvCertFB reviews what you need to know when it comes to different feline upper respiratory diseases. Learn how to approach these feline cases and what to consider for your diagnostic workup for upper respiratory tract signs in cats. If you missed MVDr. Petra Cerna on November 28, 2023 entitled Case-Based Approach to the Sneezing Cat, read the highlights below!
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TABLE 1: First-line antimicrobial options for bacterial respiratory infections in the dog and cat.
Upper respiratory tract (URT) diseases are a commonly encountered in cats and can be both acute and chronic in presentation and challenging and frustrating to treat in cats. There are several differential diagnoses for URT in cats. Most commonly, especially in younger cats, infectious agents are the main cause of URT. The pathogens that most commonly cause URT infections in cats are viral, such as feline herpes virus (FHV- 1) and feline calicivirus (FCV), or bacterial, including (Bordetella bronchiseptica, Mycoplasma spp., and Chlamydophila felis). Fungal organisms such as cryptococcus, aspergillosis can also cause URT signs in cats, especially in endemic areas. Chronic idiopathic rhinitis is commonly seen in cats and is typically considered a diagnosis of exclusion. Other diseases such as nasopharyngeal polyps, nasopharyngeal stenosis, and foreign bodies can cause URT in cats. Neoplasia such as lymphoma or adenocarcinoma can be seen, especially in older cats, and less commonly tooth root abscesses, fistulas, and laryngeal disease can be seen in cats with URT. In some cats, more than one cause of URT disease can be seen and it is therefore important to identify the underlying causes as well as most of these diseases are treatable in cats and have a good prognosis. Clinical signs that can be seen in cats with URT are sneezing and nasal congestion, ocular or nasal discharge, oral ulceration (mainly with feline calicivirus), stertor or stridor. In patients with systemic signs fever, lethargy, and inappetence/anorexia can occur. In some cases, mainly with fungal infections and neoplasia, facial asymmetry can be present, and these patients
can also present with submandibular lymphadenopathy. On the other hand, patients with nasopharyngeal polyps can present with stertorous breathing and/or otitis. While nasopharyngeal foreign bodies usually present as acute onset of sneezing and reverse sneezing, gagging, and difficulty swallowing. INFECTIOUS DISEASES FELINE HERPESVIRUS & CALICIVIRUS The pathogens that most commonly cause URT infections in cats are viral. Feline herpes virus (FHV-1) and feline calicivirus (FCV) account for approximately 90% of all feline URT disease. Viral URT disease is especially common in kittens and stressed or immunocompromised adults. Some adult cats with idiopathic chronic rhinitis are thought to have had viral (FHV or FCV) URT infections in early life as well. FCV commonly causes oral ulceration, which affects the tongue and the soft palate. These ulcers contribute to ptyalism and oral pain and result in inappetence. Cats with FHV-1 have more marked ocular signs, including blepharospasm, conjunctivitis, keratitis, chemosis, and superficial ulceration (dendritic ulcers; Figure 1). These viral pathogens enter through the oral and nasal conjunctiva; FHV-1 and FCV replicate in the nasal mucosa, nasopharynx, and tonsils. Viral shedding occurs throughout the duration of clinical signs, but many cats also continue shedding after resolution of clinical signs. In most cases, clinical signs resolve within two weeks, but shedding can continue for another few weeks or even lifelong in some cats. Cats with FHV-1 can also often be latently infected in the trigeminal ganglion and the virus can
First-Line Drug Options
Infection Type
Acute bacterial upper respiratory infection (URI) in cats.
Doxycycline or amoxicillin per os (PO)
Doxycycline or amoxicillin PO Base the choice on C & S if available
Chronic bacterial URI in cats
Table 1: Taken from Lappin et al. Antimicrobial use Guidelines for Treatment of Respiratory Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases. J Vet Intern Med. 2017 Mar;31(2):279-294.
Figure 1: Fluorescein stain in a cat with corneal ulcer secondary to FHV-1 infection. Photo courtesy of Dr. Petra Cerna, PhD, MRCVS, CertAVP, AFHEA, AdvCertFB.
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