Vaccination against feline viral rhinotracheitis in kittens with maternally derived feline viral rhinotracheitis antibodies

The efficacy of a modified live-virus intranasal vaccine and a killed-virus adjuvanted parenteral vaccine in inducing protective immunity against feline viral rhinotracheitis (FVR) was evaluated in kittens with and without maternally derived FVR antibodies. The intranasal vaccine was given as a single dose to kittens 5 weeks old, and the parenteral vaccine was administered in 2 doses at 5 and 7 weeks of age. Seroconversion was delayed for 5 to 10 days in kittens with maternally derived antibodies, but occurred in all vaccinated kittens by 8 weeks of age. When virulent FVR virus was given, both vaccines provided satisfactory protection against disease but did not prevent infection. The results indicated that the modified live-virus intranasal vaccine or the killed-virus adjuvanted parenteral vaccine can be used successfully in kittens with residual maternally derived FVR antibodies.     

An immunofluorescence diagnostic test for feline viral rhinotracheitis.

Hyperimmune serum against feline viral rhinotracheitis was produced in a goat and conjugated with a fluorescent dye. Cell cultures infected with rhinotracheitis virus had positive immunofluorescence. Cell cultures infected with other feline viruses and herpesviruses of other species did not fluoresce. In cats experimentally infected with rhinotracheitis virus, the virus was isolated from nasal and conjunctival swabs 1 to 9 days after inoculation. Nasal smears stained with the conjugated antiserum fluoresced 1 to 9 days after inoculation when clinical disease was most apparent. Conjunctival smears had positive immunofluorescence 1 to 6 days, but not 9 days, after inoculation. On postinoculation day 23, rhinotracheitis virus was not isolated from nasal or conjunctival swabs and nasal and conjunctival smears did not fluoresce. Rhinotracheitis virus or feline calicivirus was isolated from naturally infected cats with upper respiratory tract disease. Nasal and conjunctival smears from rhinotracheitis virus-infected cats had positive immunofluorescence in all cast showing clinical illness. Smears from 1 clinically normal cat from which rhinotracheitis virus was isolated did not fluoresce. Nasal and conjunctival smears from calicivirus-infected cats did not fluoresce.     

猫病毒性鼻气管炎的诊断与防治

猫病毒性鼻气管炎病毒,又名猫疱疹病毒1型（Feline Herpesvirus type1,FHV-1）,属于疱疹病毒科中的α-疱疹病毒,可引起猫及其他猫科动物的眼病及呼吸道疾病,发病率可达100％,成年猫死亡率很低,但幼猫的死亡率可达50％。本病在世界范围内广泛流行,我国己多次发现临床可疑病例。猫感染FHV-1后,虽然有抗体产生,但病毒可潜伏到三叉神经节,     

Fatal generalized feline viral rhinotracheitis in a young adult cat.

A 7-month-old cat died following a 17-day illness. Necropsy findings included sharply demarcated lingual ulcers and multifocal necrotic hepatitis. Intranuclear inclusions were found in the lesions, and a herpesvirus was recovered from specimens of liver and tongue. The virus was identified by neutralization with specific antiserum as feline rhinotracheitis virus.     

A survey of feline viral rhinotracheitis and feline picornavirus infection in Britain

A survey of healthy and respiratory-diseased cats, post-mortem kitten specimens and serum samples, showed the widespread occurrence of feline rhinotracheitis virus infection (FVR) and feline picornavirus infection (FPI) in Britain. Both virus groups were on occasions isolated from clinically healthy cats but they were more frequently associated with upper respiratory disease. No colony outbreak of respiratory disease was investigated without either FVR or FPI being incriminated. Clinical differentiation of FVR and FPI was imposible with certainty although FVR infection was typically more severe. Pathologically, FVR could be distinguished particularly in the early stages by the presence of specific intranuclear inclusions in mucosal and submucosal gland cells of the respiratory tract and by a generally more severe mucosal destruction. FPI was typified by a mild disorganization of mucosae and mononuclear cell infiltrations. Serological investigations demonstrated that, in colonies particularly, high titres of antibody against both FVR virus and a spectrum of feline picornaviruses were attained in adult cats, a reflection of the endemic nature of these viruses. Bacteria played a secondary role in both FVR and FPI, and there was no evidence for chlamydial agents being important in the aetiology of feline respiratory disease in Britain. Résumé. Une étude de chats sains et atteints de maladies des voies respiratoires, de spécimens d'autopsie de chatons et d‘échantillons de sérum montre que les rhinotrachéites félines avec infection d'origine virale (RFV) et les infections ftlines de “picornavirus” (IFP) sont très répandues en Grande-Bretagne. A différentes occasions, les deux groupes de virus, provenant de chats sains du point de vue clinique, ont été isolés mais ces virus étaient le plus souvent lies aux maladies respiratoires d'origine otorhinolaryngologique. Toutes les recherches sur les maladies respiratoires se declarant par colonies indiquaient la présence soit de RFV ou de I'IFP. La dif-férenciation clinique certaine de RFV et d'IFP fut impossible bien que l'infection RFV fût plus grave come prévu. Pathologiquement, il fut possible de distinguer le RFV, surtout dans les premiers stades, par la présence d'inclusions intranucléaires spécifiques dans les cellules des glandes muqueuses et submuqueuses des voies respiratoires et par une destruction muqueuse généralement plus grave. L'IFP était caracterisée par une légère désorganisation des membranes muqueuses et des infiltrations de cellules mononucléaires. Des recherches sérologiques ont montré, surtout pour les colonies, qu'on rencontre des titres élevés d'anticorps contre le virus RFV ainsi qu'un spectre de “piconavirus” felins chez des chats adultes, ce qui réflète la nature endémique de ces virus. Les bactéries n'ont joué qu'un rôle secondaire, à la fois dans les RFV et les IFP et il n'y eut pas d'indices indiquant l'importance des agents “Chlamydiaux” dans l‘étiologie des maladies respiratoires félines en Grande-Bretagne. Zusammenfassung. Ein zusammenfassender Bericht über geusunde Katzen und solche mit Erkrankungen der Atmungsorgane, Sektionsproben junger Katzen und Serumproben zeigte das verbreitete Auftreten der Rhinotracheitis-Virus infektion der Katzen (FVR) und der Picornavirusinfektion der Katzen (FPI) in Grossbritannien. Beide Virusgmppen wurden gelegentlich aus klinisch gesunden Katzen isoliert, waren aber häufiger mit Erkrankungen der oberen Atemwege verbunden. Es wurde kein massiertes Auftreten von Erkrankungen der Atmungswege untersucht, ohne dass entweder FVR oder FPI als Ursache anzusehen waren. Die klinische Differenzierung von FVR und FPI war nicht mit Sicherheit möglich, obwohl die FVR-Infektion typisch schwerer war. Pathologisch konnte FVR besonders in den Frühstadien durch die Anwesenheit spezifischer intranuklearer Einschlüsse in mucösen und submucösen Drüsenzellen des Respirationstraktes und durch eine allgemein schwerere Schleimhautzer-störung unterschieden werden. FPI war durch eine schwache Disorganisation mucöser und mononuklearer Zellinfiltrationen charakterisiert. Serologische Untersuchungen zeigten, dass besonders in Kolonien hohe Antikörperkonzentrationen gegen FVR-Virus und ein Spektrum von Picornaviren der Katze bei erwachsenen Katzen erreicht wurden, was auf den endemischen Charakter dieser Viren hinweist. Bakterien spielten bei FVR und FPI eine sekundäre Rolle, und es liess kein Anzeichen darauf schliessen, dass chlamydiale Agentien für die Ätiologie der Erkrankungen der Atmungsorgane von Katzen in Grossbritannien eine Rolle spielten.     

Experimental induction of feline viral rhinotracheitis virus re-excretion in FVR-recovered cats.

The re-excretion of feline viral rhinotracheitis (FVR) virus (feline herpesvirus I) by FVR-recovered cats is recorded both spontaneously and following a variety of stimuli, namely, corticosteroid administration, change of housing, and parturition and lactation. At least 27 of 33 (82%) FVR-recovered cats studied were shown to be viral carriers. The carrier state was characterised by periods of viral latency interspersed with episodes of viral shedding. Administration of 0-75 mg dexamethasone trimethylacetate and 2-25 mg prednisolone on days 0,2 and 4 resulted in re-excretion after a mean lag period of 7-2 days in 22 of 32 (69%) FVR-recovered cats on a total of 31 of 57 (54%) occasions. Rehousing resulted in virus re-excretion after a mean lag period of 7-2 days in four of 22 (18%) cats tested on a total of six of 40 (15%) occasions. Apparently spontaneous shedding occurred on a total of 10 occasions in nine of 31 (29%) cats during a mean observation period of 8-8 months. Four of six FVR-recovered queens in a total of four of 10 litters (40%) shed virus within two to 10 weeks of parturition. Serum neutralising antibody titres were generally boosted at the time of first re-infection but afterwards remained essentially constant. Although 82% of cats in these studies were shown to be viral carriers, only 45% of cats shed virus spontaneously or as a result of the natural stress situations and it is postulted that these naturally excreting cats are of most significance epidemiologically.     

Immunogenic and protective effects of the F-2 strain of feline viral rhinotracheitis virus.

The F-2 strain of feline viral rhinotracheitis (FVE) virus was administered by intramuscular (IM) injection to susceptible cats. The cats developed serum-neutralizing antibodies and were protected to a significant degree when given, by intranasal (IN) instillation challenge inoculum of a virulent strain of FVR virus.     

In vitro antiviral efficacy of ribavirin against feline calicivirus, feline viral rhinotracheitis virus, and canine parainfluenza virus.

Ribavirin had marked in vitro activity against feline calcivirus, strain 255, and canine parainfluenza virus, but showed only slight antiviral effect on feline viral rhinotracheitis virus. Antiviral activity was manifested by partial to complete suppression of viral cytopathic effect and of viral replication, depending on concentration of ribavirin in the culture medium and dosage of viral inoculum. Concentrations of ribavirin as small as 3.2 microgram/ml and 1.0 microgram/ml showed some activity against feline calcivirus and canine parainfluenza virus, respectively.     

Interaction of an intranasal combined feline viral rhinotracheitis, feline calicivirus vaccine and the FVR carrier state

Eight cats were vaccinated intranasally with a combined feline calicivirus/feline viral rhinotracheitis (FVR) virus commercial vaccine. Following intranasal challenge with a field strain of FVR virus and subsequent treatment with corticosteroid, no virus was recovered from any of the eight cats, while FVR virus was recovered following corticosteroid treatment from two of four unvaccinated and challenged controls. No evidence was found for the development of an FVR virus carrier state with the intranasal vaccine virus.     

Effect of cyclophosphamide immunosuppression on the immunity of turkeys to viral rhinotracheitis.

Turkey poults, free of antibodies to turkey rhinotracheitis (TRT) virus were treated with cyclophosphamide on days 1, 2 and 3 after hatching and vaccinated by eyedrop when 10 days old with a Vero cell-attenuated preparation of TRT virus. No ELISA antibodies to TRT virus developed in the sera of these poults but they were as resistant to virulent virus challenge 21 days later as vaccinated groups which were not cyclophosphamide-treated but produced humoral antibodies. Following challenge with virulent virus at 31 days old cyclophosphamide-treated unvaccinated poults developed a more severe clinical response than untreated birds and had higher virus titres in tracheal swabs. The findings show that the respiratory tract of turkeys may be resistant to TRT despite the absence of ELISA antibodies in the serum.     

Diagnosis of feline viral infection

A diagnosis of a specific viral disease in the cat involves a combination of an accurate history, careful observation of disease signs, demonstration of characteristic clinical pathologic changes, and isolation or identification of the virus. Isolation or identification of a virus from the patient does not establish that the disease observed was caused by the virus so isolated or identified; correlation and proper interpretation of all findings are necessary to establish a diagnosis. Virus identification may involve office laboratory tests, such as cytology or ELISA, or more specialized procedures. Whether specimens are to be sent out for specialized tests or office laboratory procedures are to be used, the veterinary practitioner must not only know what specimens are required but must also understand the test and be able to properly interpret the results in light of the patient's observed condition.     

Investigation of the induction of antibodies against Crandell-Rees feline kidney cell lysates and feline renal cell lysates after parenteral administration of vaccines against feline viral rhinotracheitis, calicivirus, and panleukopenia in cats

OBJECTIVE: To determine whether administration of Crandell-Rees feline kidney (CRFK) cell lysates or vaccines against feline viral rhinotracheitis, calicivirus, and panleukopenia (FVRCP vaccines) that likely contain CRFK cell proteins induces antibodies against CRFK cell or feline renal cell (FRC) lysates in cats. ANIMALS: 14 eight-week-old cats. PROCEDURE: Before and after the study, renal biopsy specimens were obtained from each cat for histologic evaluation. Each of 4 FVRCP vaccines was administered to 2 cats at weeks 0, 3, 6, and 50. Between weeks 0 and 50, another 3 pairs of cats received 11 CRFK cell lysate inoculations SC (10, 50, or 50 microg mixed with alum). Clinicopathologic evaluations and ELISAs to detect serum antibodies against CRFK cell or FRC lysates were performed at intervals. RESULTS: Cats had no antibodies against CRFK cell or FRC lysates initially. All cats administered CRFK cell lysate had detectable antibodies against CRFK cell or FRC lysates on multiple occasions. Of 6 cats vaccinated parenterally, 5 had detectable antibodies against CRFK cell lysate at least once, but all 6 had detectable antibodies against FRC lysate on multiple occasions. Cats administered an intranasal-intraocular vaccine did not develop detectable antibodies against either lysate. Important clinicopathologic or histologic abnormalities were not detected during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Parenteral administration of vaccines containing viruses likely grown on CRFK cells induced antibodies against CRFK cell and FRC lysates in cats. Hypersensitization with CRFK cell proteins did not result in renal disease in cats during the 56-week study.     

Three-year duration of immunity in cats following vaccination against feline rhinotracheitis virus, feline calicivirus, and feline panleukopenia virus

Forty-two seronegative cats received an initial vaccination at 8 weeks of age and a booster vaccination at 12 weeks. All cats were kept in strict isolation for 3 years after the second vaccination and then were challenged with feline calicivirus (FCV) or sequentially challenged with feline rhinotracheitis virus (FRV) followed by feline panleukopenia virus (FPV). For each viral challenge, a separate group of 10 age-matched, nonvaccinated control cats was also challenged. Vaccinated cats showed a statistically significant reduction in virulent FRV-associated clinical signs (P = .015), 100% protection against oral ulcerations associated with FCV infection (P < .001), and 100% protection against disease associated with virulent FPV challenge (P < .005). These results demonstrated that the vaccine provided protection against virulent FRV, FCV, and FPV challenge in cats 8 weeks of age or older for a minimum of 3 years following second vaccination.     

猫病毒性鼻气管炎治疗性药物研究进展

猫病毒性鼻气管炎(Feline viral rhinotracheitis, FVRs)是由1型猫疱疹病毒引起的对猫科动物健康构成严重威胁的病毒性传染病,其传播迅速、潜伏感染的特点一直以来都是宠物临床中诊断与治疗的难点。目前存在多种猫疱疹病毒治疗药物,但是对药物治疗效果的评价存在很大的争议。因此,充分认识抗疱疹病毒药物的研究现状及治疗效果对于FVRs治疗方案的制定十分重要。本文对近年来抗猫疱疹病毒药物及治疗效果的研究进展进行了综述,以期为FVRs的临床治疗提供理论参考。     

Feline viral rhinotracheitis virus: explant and cocultivation studies on tissues collected from persistently infected cats

Tissues from 16 feline viral rhinotracheitis (FVR) carrier cats and 15 controls were examined by the techniques of homogenisation, cocultivation and explant cultivation. The tissues examined included trigeminal ganglion and maxillary nerve, olfactory lobe and nerve endings, tonsils, submandibular lymph node, spleen and parotid salivary gland. Most of the cats were shedding FVR virus in the oropharynx at the time the tissues were collected. No evidence of a persistent FVR virus infection was found in any of the tissues. Trigeminal ganglion explant cultures from six FVR virus carrier cats were shown to be latently infected with feline syncytia forming virus by treatment with 5-iododeoxyuridine. Five control cats had trigeminal ganglion explant cultures similarly treated but produced no evidence of infection. The possible significance of this is discussed.