Feline Panleucopaenia Research Articles

The efficacy of a multivalent calicivirus, herpesvirus and parvovirus vaccine and a rabies vaccine is not affected when administered in combination

The results of a serological study examining the antibody responses generated in cats following administration of a trivalent feline vaccine (feline calicivirus [FCV], feline herpesvirus [FHV] and feline panleucopaenia virus [FPV]; Versifel CVR) in combination with an inactivated rabies vaccine, in compliance with European Pharmacopoeia requirements to support new product registrations, are presented.Nine week old cats were allocated to one of three groups, 10 cats per group. Group 1 received the CVR vaccine on days 0 and 21, group 2 received the rabies vaccine on day 21 and group 3 received the CVR vaccine on day 0 and the CVR vaccine reconstituted with the rabies vaccine (i.e., administered simultaneously) on day 21. Blood samples were collected from each animal, on days 0, 21, 28, 35, 42 and 49; and antibody titres determined using haemagglutination inhibition assay or virus neutralisation test.FHV and FPV antibody responses in the group 3 combination administration were considered non-inferior to the responses in the group 1 CVR-only at all time points (days 28, 35, 42 and 49). However for FCV, group 3 was considered non-inferior to the responses in group 1 on days 28, 35 and 42; but not on day 49. For rabies, group 3 was only considered non-inferior to the responses in group 2 on day 49; an apparent inferiority was observed on days 28, 35 and 42. However, in all cases cats that received the combination administration seroconverted with antibody titres at a magnitude shown in other studies to be protective against virulent challenge, and also at a titre deemed adequate by the European Pharmacopeia monograph 04/2013:0451 (Rabies vaccine [inactivated] for Veterinary use).In conclusion, the data show that combining these two separate vaccines in one administration has limited impact on their ability to generate serological responses, and that these responses are still of a magnitude previously demonstrated to be protective.

A Review of Feral Cat Eradication on Islands

Abstract: Feral cats are directly responsible for a large percentage of global extinctions, particularly on islands. We reviewed feral cat eradication programs with the intent of providing information for future island conservation actions. Most insular cat introductions date from the nineteenth and twentieth centuries, whereas successful eradication programs have been carried out in the last 30 years, most in the last decade. Globally, feral cats have been removed from at least 48 islands: 16 in Baja California (Mexico), 10 in New Zealand, 5 in Australia, 4 in the Pacific Ocean, 4 in Seychelles, 3 in the sub‐Antarctic, 3 in Macaronesia (Atlantic Ocean), 2 in Mauritius, and 1 in the Caribbean. The majority of these islands (75%; n= 36) are small (≤5 km2). The largest successful eradication campaign took place on Marion Island (290 km2), but cats have been successfully removed from only 10 islands (21%) of ≥10 km2. On Cousine Island (Seychelles) cat density reached 243 cats/km2, but on most islands densities did not exceed 79.2 cats/km2 (n= 22; 81%). The most common methods in successful eradication programs were trapping and hunting (often with dogs; 91% from a total of 43 islands). Frequently, these methods were used together. Other methods included poisoning (1080; monofluoracetate in fish baits; n= 13; 31%), secondary poisoning from poisoned rats (n= 4; 10%), and introduction of viral disease (feline panleucopaenia; n= 2; 5%). Impacts from cat predation and, more recently, the benefits of cat eradications have been increasingly documented. These impacts and benefits, combined with the continued success of eradication campaigns on larger islands, show the value and role of feral cat eradications in biodiversity conservation. However, new and more efficient techniques used in combination with current techniques will likely be needed for success on larger islands.

Effects of Feline Panleucopaenia on the Population Characteristics of Feral Cats on Marion Island

Taking the Berberis aggregate shrubs in the ecotone of dry valley and montane forests in upper reaches of Minjiang River as study objects, and by the methods of tracking grazing and field survey, this paper studied the characteristics of habitat utilization by livestock and the features of grazing-path. The major factors affecting the features of grazing-path were screened by redundancy analysis (RDA), and the relationships of the grazing-path features with the coverage, size class, and distribution pattern of the shrubs were analyzed. It was shown that the distribution pattern of the grazing-path could intuitively reflect the characteristics of the habitat utilization by livestock, being in accordance with the results of tracking grazing. The Morisita index at 5 m scale could objectively reflect the distribution type of the grazing-path. Sample plots 1, 2 and 6 presented a contagious distribution of grazing-path, while the other plots showed regular distribution. In slope scale, the coverage and height of the shrubs were the notable affecting factors, which had negative correlations with the grazing-path features. There was a significant negative correlation between the coverage of B. aggregate population and the area of grazing-path. The population structure of B. aggregate had a close correlation with the distribution of grazing-path. The ratio of the long axis to short axis of the shrubs was averagely 1.29, and the shape of the shrubs approached to round. It was considered that the grazing-path landscape and the livestock on the grazing-paths had the function of reconstructing the shape of the shrubs. The directionality of the population pattern of B. aggregate was generally in line with the distribution type of grazing-path, but actually, they were opposite in distribution. The patches of the shrubs were in aggregated or uniform distribution in the areas deviated from the grazing-path.

Parvovirus (feline panleucopaenia virus) plaque formation.

A plaque assay was developed for feline parvovirus (FPV; feline panleucopaenia virus) in a feline embryo (FEmb) cell line. Higher numbers and larger diameter plaques were obtained with a) seeding rates of 0.7 X 10(5) and 1.5 X 10(5) cells cf. 3 X 10(5) and 6 X 10(5) cells/well of 35 mm diameter, b) synchronised cells infected at the G1-S interface cf. nonsynchronised cells and c) 5 to 6 days incubation post inoculation. The plaque assay was standardised by using serum deprivation for 24 hours to synchronize cells, a seeding rate of 1.5 X 10(5) cells/35 mm diameter well, inoculation of virus 16 hours post seeding followed by 5 days incubation. The standardised assay gave consistent, reproducible results. A dose-response curve using the assay showed a linear, 45 degrees slope, relationship between plaque forming units and virus dilution which further verified the sensitivity and reliability of the assay. Plaques produced by "wild" type and plaque purified virus were invariably non uniform in diameter; diameter of plaques in fact followed a normal frequency distribution under standard assay conditions.

Recovery of viral agents from the central nervous system of cats

Isolation of viruses from the central nervous system (CNS) of cats was attempted using an explant culture technique and subsequent co-cultivation with Crandell feline kidney (CRFK) or Vero cells. Feline syncytia-forming virus was isolated from the CNS of 11 of 16 cats where the initial co-cultivation was with CRFK cells. Feline panleucopaenia virus was isolated from the CNS of 2 adult cats. Co-cultured cells from the CNS of 3 cats contained eosinophilic cytoplasmic and intranuclear inclusions. The cytoplasmic inclusions consisted of tubular structures, 16–18 nm in diameter and up to 500 nm in length, which were similar in morphology to paramyxovirus nucleocapsids. The 3 co-cultured cells with cytoplasmic and intranuclear inclusions showed haemadsorption of guinea pig erythrocytes. The possible identity of these structures, and their association with a previously described primary focal demyelinating lesion in the CNS of cats, is discussed.

Pathological and virological observations on canine parvoviral enteritis and myocarditis in the Wellington region

Abstract Five outbreaks of acute enteritis and one of myocarditis in 5 to 12-week-old puppies are reported. In cases of enteritis the initial clinical finding of slight malaise was followed within 24 hours by severe vomiting, diarrhoea, dehydration and death in most cases. The lesions of acute necrotizing enteritis and widespread lymphoid depletion were identical to those of feline panleucopaenia. In the outbreak of myocarditis, 3 puppies were founddead and a fourth developed congestive heart failure. Parvoviral-like particles were found in the faeces of 5 cases of enteritis by electron microscopy and virus was isolated from 2 dogs, using a feline kidney cell line. The isolates demonstrated the physicochemical characteristics of a parvovirus and haemagglutinated porcine red blood cells at 4°C and 22°C but not 37°C. The isolates were antigenically related to feline panleucopaenia virus by immune aggregation, haemagglutination inhibition and immunofluorescence. Fourteen of 48 sera from local dogs had signif...

Further studies with a living attenuated vaccine against feline panleucopaenia.

ABSTRACTSeventy‐two hours after the administration of a single dose of high passage living attenuated feline panleucopaenia vaccine, cats were protected against experimental challenge and even at 48 hours the effects of challenge were reduced. The antibody response persisted at high titre for at least 23 months. Antibody titres following vaccination were better than those associated with virulent virus. The attenuation of virulent feline panleucopaenia virus by serial passage in feline embryonic cell culture has produced a living vaccine which is both antigenic and immunogenic.Résumé. Soixante‐douze heures après l'administration d'une seule dose du vaccin pour maladie des jeunes chats, vaccin vivant atténué à passage élévé, les chats étaient protégés contre des tests expérimentaux et les effets des tests étaient même réduits à 48 heures. La réponse anticorps a persisté à titre élévé pendant au moins 23 mois. Des titres anticorps suivant la vaccination étaient meilleurs que ceux associés avec le virus virulent. L'atténuation du virus virulent pour la maladie des jeunes chats, par passage en série dans la culture des cellules embryonnaires chez les félins, a produit un vaccin vivant qui est à la fois antisomatogtne et immunogène.Zusammenfassung. Zweiundsiebzig Stunden nach der Darreichung von hoher Passage leben‐derattenuierter Katzenfieber‐ (Agranulozytose) Vakzine waren Katzen gegen experimentale Immunitätsteste geschützt und selbst nach 48 Stunden waren die Auswirkungen des Immunitätsteste reduziert. Die Schutzstoffreaktion hielt bei hohem Titer für wenigstens 23 Monate an. Schutzstofftiter die einer Impfung folgten waren besser als jene die mit virulentem Virus verbunden sind. Die Verminderung von virulentem Katzenfieber‐ (Agranulozytose) Virus durch Reihenpassage in katzenembryonaler Zellenkultur hat eine lebende Vakzine produziert, die antigen sowohl wie immunisierend ist.

Feline Panleucopaenia Virus: IV.—Methods for Obtaining Reproducible in vitro Results

Studies of the irregular and transient in vitro cytopathic effect of feline panleucopaenia virus have shown that the transiency of cellular destruction is due to a selective and specific affinity of the virus for cells in active mitosis. As cells reach the resting stage of a full tissue culture monolayer, they become resistant to virus action, and this fact, coupled with the presence of widespread heat stable virus inhibitors in sera used to supplement media, is the cause of variability of in vitro cytopathic effect. By injecting cells during the young, actively mitotic phase, and using non-inhibitory sera, good reproducible results may be obtained. By the application of such techniques in vitro, it was possible to obtain a growth curve for the virus, the major features of which are presented. The significance to pathogenicity of a virus with this particular tropism for actively dividing cells is discussed.

Problems in classification of feline panleucopaenia virus.

Mayor and Melnick1 have recently presented data on a group of small single stranded DNA viruses which cannot confidently be placed in any recognized virus group, and they tentatively propose a group designation of picodna-viruses for these viruses. Present work on feline panleucopaenia (FP) virus strains has resulted in findings which suggest a possible classification of such strains in this grouping.

Feline Panleucopaenia Virus: III.—Some Properties Compared, to a Feline Herpes Virus

SUMMARY In contrast to a herpes virus of feline viral rhinotracheitis (FVR), feline panleucopaenia (FP) virus is shown to be chloroform, ether, heat, acid, phenol, and trypsin stable. Both viruses lose infectivity within 24 hours when treated with 0·2% formalin, and both, on inhibition studies with 5-bromodeoxyuridine (BUDR), behave as DNA viruses. On filtration studies, FP virus is estimated to have a minimal infective particle size of 74 mµ compared to 116 mµ for FVR virus. The general differentiation of the 2 viruses is discussed, and the conclusion reached that FP virus has properties which suggest that it is a member of either the adeno or the pap ova-virus groups.

Feline Panleucopaenia: I.—Identification of a Virus Associated with the Syndrome

SUMMARY The relationship between a virus isolated from a leopard spleen and the feline panleucopaenia syndrome was investigated. Inoculation of kittens with tissue culture fluids containing leopard virus (LV) produced a syndrome which was indistinguishable from that produced in a comparable group of kittens inoculated with feline panleucopaenia infected tissue, and immunity to cross challenge was established in each group. Susceptibility to challenge in each group was correlated with low levels of serum neutralizing antibody to leopard virus, and resistance to cross challenge with comparable increases in antibody to LV. Agents similar to leopard virus were isolated from the tissues of domestic cats naturally infected with feline panleucopaenia and evidence of a relationship between the agents was obtained by comparative serological and cytopathic studies. It is concluded that the agent isolated from the leopard spleen is similar to that involved in the feline panleucopaenia syndrome in domestic cats, and in all probability is the basic cause of the syndrome.

Feline Panleucopaenia Virus: II.—Some Features of the Cytopathic Effects in Feline Kidney Monolayers

SUMMARY The cytopathic effect (CPE) of a strain of feline panleucopaenia virus in kitten kidney monolayers is shown to be of transient nature affecting a small and variable number of cells in the monolayer. These cells show intranuclear inclusions, whose development through eosinophilia to basophilia, is described in stages. The detection of the cytopathic effect depends upon daily staining of the monolayer, and varies in extent depending upon concentration of inoculum, temperature of incubation, media used, age of monolayer, passage level of cells and in different batches of kidney cells.

VIRUS OF FELINE PANLEUCOPAENIA.

PROGRESS in understanding the immunological features of feline panleucopaenia has, for many years, been impeded due to failure to isolate the causal agent of the disease. That this agent has the properties of a virus has been evident since the original observations of Verge and Christoforoni1, but although many viruses have been isolated from sick and healthy cats, none has been shown to be related to the feline panleucopaenia syndrome2.