[Progressive retinal atrophy in Abyssinian and Somali cats in the Netherlands (1981-2001)]

From 1981 to 2001, 248 Abyssinian and 127 Somali cats in the Netherlands were examined for hereditary eye disease. Distinct ophthalmoscopic signs consistent with hereditary progressive retinal atrophy (PRA) were observed in 11 Abyssinian cats, and subtle signs in 3 Abyssinian cats. A familial relationship was detected in 13 out of 14 of these cats, which supports a hereditary basis to the condition. Distinct funduscopic signs of retinal degeneration were observed at a median age of 4 years. One cat with advanced retinal degeneration was only 7 months old, whereas the remaining 10 cats were between 2 and 12 years old at the time of diagnosis. These differences in the age of onset are suggestive of at least two types of PRA occurring in Abyssinian cats in the Netherlands: a dysplastic, early-onset and a late-onset retinal degeneration. A large-scale and systematic examination programme for hereditary eye disease will be necessary to assess the incidence of PRA in the Dutch population of Abyssinian and Somali cats as a whole, and to provide a basis for a preventive breeding programme.

Evaluation of sedative and cardiorespiratory effects of romifidine and romifidine-butorphanol in cats

OBJECTIVE

To determine sedative and cardiorespiratory effects of romifidine alone and romifidine in combination with butorphanol and effects of preemptive atropine administration in cats sedated with romifidine-butorphanol.

DESIGN

Randomized crossover study.

ANIMALS

6 healthy adult cats.

PROCEDURES

Cats were given saline (0.9% NaCl) solution followed by romifidine alone (100 microg/kg [45.4 microg/lb], i.m.), saline solution followed by a combination of romifidine (40 microg/kg [18.1 microg/lb], i.m.) and butorphanol (0.2 mg/kg [0.09 mg/lb], i.m.), or atropine (0.04 mg/kg [0.02 mg/lb], s.c.) followed by romifidine (40 microg/kg, i.m.) and butorphanol (0.2 mg/kg, i.m.). Treatments were administered in random order, with > or = 1 week between treatments. Physiologic variables were determined before and after drug administration. Time to recumbency, duration of recumbency, time to recover from sedation, and subjective evaluation of sedation, muscle relaxation, and analgesia were assessed.

RESULTS

Bradycardia developed in all cats that received saline solution and romifidine-butorphanol or romifidine alone. Preemptive administration of atropine prevented bradycardia for 50 minutes in cats given romifidine-butorphanol. Oxyhemoglobin saturation was significantly decreased 10 minutes after romifidine-butorphanol administration in atropine-treated cats.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that administration of romifidine alone or romifidine-butorphanol causes a significant decrease in heart rate and that preemptive administration of atropine in cats sedated with romifidine-butorphanol effectively prevents bradycardia for 50 minutes.

Protection against oronasal challenge with virulent feline leukaemia virus lasts for at least 12 months following a primary course of immunisation with Leukocell 2 vaccine

The duration of immunity provided by a feline leukemia virus (FeLV) vaccine, Leukocell 2, was determined. Kittens were vaccinated when 9 and 12 weeks of age and were challenged 12 months later with FeLV-A/Glasgow-1. An oronasal challenge protocol without corticosteroid enhancement was developed in order to induce a persistent viraemia in a high proportion of adult cats. Fourteen of 18 (80%) of the vaccinated cats challenged in this way remained non-viraemic while 9/15 (60%) of age-matched controls became persistently infected, a preventable fraction of 63%. This difference was statistically significant (P=0.038). For comparison, 10 of 12 (83%) 15-17-week-old kittens challenged in the same way became persistently infected, confirming the relative resistance of adult animals to FeLV. Tests for virus neutralising and anti-feline oncornavirus-associated cell membrane antigen (FOCMA) antibodies suggested that the former were more important than the latter in protection. Thus, Leukocell 2 protected a significant proportion of cats from FeLV challenge 1 year after primary vaccination as kittens.

Bovine spongiform encephalopathy update

Bovine spongiform encephalopathy (BSE) is a zoonosis being the origin of variant Creutzfeldt-Jakob disease and an important cattle disease in its own right. Countries have been slow to learn the importance of protecting, not only their cattle populations, but also their human populations. Since 2000, several additional European countries have reported BSE in native-born stock and this has led to a concern about the BSE status of countries that have imported cattle and catlle products from infected countries. Extensive feed and offal bans and application of newly-developed, "Rapid" tests for prion protein in central nervous tissue of targeted, high-risk animals and slaughter cattle over 30 months old now provides the tools whereby the public are fully protected and BSE can be eradicated.

World Wide Web-based survey of vaccination practices, postvaccinal reactions, and vaccine site-associated sarcomas in cats

OBJECTIVE

To quantify incidence of vaccination practices, postvaccinal reactions, and vaccine site-associated sarcomas in cats.

DESIGN

Epidemiologic survey. Animals-31,671 cats vaccinated in the United States and Canada by veterinarians with World Wide Web access.

PROCEDURE

Veterinarians used secure Web-based survey forms to report data regarding administered vaccines, postvaccinal inflammatory reactions, vaccine site-associated sarcomas, and detailed information and history on each sarcoma. Data were collected from Jan 1, 1998 to Dec 31, 2000, allowing a 1- to 3-year follow-up of vaccinated cats.

RESULTS

Participants reported administering 61,747 doses of vaccine to 31,671 cats; postvaccinal inflammatory reactions developed in 73 cats (11.8 reactions/10,000 vaccine doses), and qualifying vaccine site-associated sarcomas developed in 2 cats (0.63 sarcomas/10,000 cats; 0.32 sarcomas/10,000 doses of all vaccines).

CONCLUSIONS AND CLINICAL RELEVANCE

These findings indicate that the incidence of vaccine site-associated sarcomas is low and is not increasing. Thoughtful consideration of the relative risks and benefits of specific vaccines remains the best means of reducing the incidence of sarcomas. It is not necessary to remove postvaccinal granulomas unless malignant behavior is apparent or they persist > 4 months.

Home monitoring of the diabetic pet

Home monitoring of the diabetic pet is a challenging proposition for many pet owners. Diabetes, unlike many other diseases, requires that the client, not the veterinarian, treat the disease. It is crucial that veterinarians reinforce and educate clients that successful treatment of diabetes mellitus will depend solely on the client's actions throughout the course of the treatment. This article provides guidelines on educating clients in the home monitoring process. This commonsense approach covers elements of in-home monitoring, including general appearance, clinical signs, behavior changes, feeding schedules, and medication administration. Additionally, thorough explanation is provided for clients who wish to take a more active role in obtaining and monitoring blood and urine chemistry values. This information is provided to assist the veterinary technician and veterinarian in educating clients of their responsibility in treating this disease.

Measurement of capillary blood glucose concentrations by pet owners: a new tool in the management of diabetes mellitus

Recently a new method for capillary blood sampling from the ears of dogs and cats was described, which allows the measurement of glucose concentration by means of portable glucose meters. The authors of this report evaluated the suitability of this method for use by pet owners and the potential technical problems. The owners of seven healthy dogs and seven healthy cats were asked to perform two glucose curves (measuring blood glucose concentration every 2 hours for a total of 12 hours). All dog owners and three cat owners were able to perform a reliable blood glucose curve. The most frequently encountered problems were inadequate formation of a blood drop due to excessive digital pressure on the pinna, repeatedly depressing the plunger of the lancet device instead of allowing the negative pressure to slowly build up, and failure to fill the test strip up to the mark. The authors conclude that these steps of the procedure need to be stressed during technique demonstration and that home monitoring of blood glucose concentrations may serve as a new tool in the management of diabetic dogs and cats.

Monitoring techniques for diabetes mellitus in the dog and the cat

One of the keys to achieving glycemic control in animals with diabetes mellitus is the appropriate selection and interpretation of analytic monitoring tests. Diabetic animals are subject to many of the same problems described in human diabetics. Diabetics are more susceptible to infection, and wound healing is often impaired. Decreased insulin promotes lipolysis and moderate hyperlipidemia, which can lead to falsely lowered fructosamine levels, impaired renal circulation, and atherosclerosis. Hyperglycemic, hypoinsulinemic animals continue to lose weight despite an increased appetite and an increased intake because they are not able to use glucose. Many unregulated diabetic animals will present with vomiting and diarrhea that can exacerbate electrolyte abnormalities seen with the osmotic diuresis present in an uncontrolled state. Canine diabetics are prone to cataract formation secondary to sorbitol accumulation in the lens. Cats, on the other hand, can present with diabetic distal neuropathy, which may be reversible with appropriate treatment. With all of these potential complications, it is important to monitor these animals regularly; this is the only way that glycemic control can be properly maintained over time. This article reviews the monitoring parameters available to the modern practitioner and outlines the benefits of each test, as well as caveats, in their interpretation.

Portable blood glucose meters as a means of monitoring blood glucose concentrations in dogs and cats with diabetes mellitus

The use of portable blood glucose meters (PBGM) has become common in veterinary medicine as a rapid means of monitoring animals' blood glucose in a variety of medical conditions. These hand-held monitors allow for diagnostic and therapeutic decisions to be made quickly and relatively inexpensively using only a small amount of blood. Both in conditions resulting in hyperglycemia, such as diabetes mellitus, and in those resulting in hypoglycemia, such as sepsis or the presence of an insulinoma, veterinarians have come to rely on PBGM to provide critical information on the status of their animal patients. In particular, PBGM are frequently used to measure individual blood glucose values in an animal over a period to create a blood glucose curve when evaluating the effectiveness of insulin therapy in diabetic dogs and cats.

Virucidal efficacy of four new disinfectants

Virucidal efficacy was evaluated for four recently available disinfectants: chlorine dioxide, potassium peroxymonosulfate, a quaternary ammonium compound, and citricidal (grapefruit extract). Sodium hypochlorite (3%) and tap water were used as positive and negative controls respectively. Feline herpesvirus, feline calicivirus, and feline parvovirus were exposed to the manufacturers' recommended dilutions of the evaluated disinfectants. Both chlorine dioxide and potassium peroxymonosulfate completely inactivated the three viruses used in this study. These disinfectants can aid in controlling nosocomial transmission of viruses with less of the deleterious effects of sodium hypochlorite. The quaternary ammonium compound evaluated in this study and citricidal were not effective against feline calicivirus and feline parvovirus.

Studies of the efficacy of a novel intranasal vaccine against feline bordetellosis

A novel intranasal vaccine against disease caused by Bordetella bronchiseptica in cats was tested in a series of three experiments. In the first experiment a vaccinated group and an unvaccinated control group of kittens were challenged by the aerosol route with virulent B bronchiseptica three weeks after they had been vaccinated. The control kittens developed upper respiratory tract signs typical of feline B bronchiseptica infection, including rhinitis, a serous ocular and nasal discharge, fever, sneezing and coughing. The mean (sd) clinical score for the cats in the unvaccinated control group was 19.5 (5.4) compared with 1.53 (1.9) for the vaccinated group. In the second experiment vaccinated kittens were challenged with virulent B bronchiseptica 72 hours after they were vaccinated. Their mean clinical score was 2.76 (2.62) compared with 13.4 (3.33) for the control group. In the final experiment, vaccinated and unvaccinated control cats were challenged after six or 12 months. After six months the mean clinical scores were 13.9 (4.7) for the control group, compared with 1.33 (1.56) for the vaccinated group, and after 12 months the scores were 9.92 (5.79) for the control group compared with 0.92 (0.89) for the vaccinated group.

Rabies antibody testing and the UK Pet Travel Scheme

The Pet Travel Scheme (PETS) commenced on February 28, 2000, allowing pet dogs and cats from named countries to enter the UK without spending six months in quarantine as long as they met specific criteria. Since the start of the scheme to the end of February 2002, more than 45,000 animals have successfully entered the UK under PETS. In this article, Dr Tony Fooks and colleagues consider the results of serological testing under the scheme at the Veterinary Laboratories Agency and look to future developments.

In vitro susceptibility of Microsporum canis and other dermatophyte isolates from veterinary infections during therapy with terbinafine or griseofulvin

We investigated the in vitro activity of terbinafine against fresh veterinary isolates of Microsporum canis and the potential of this organism to develop resistance in vivo during oral therapy. Dermatophyte cultures (n = 300) were obtained from naturally infected cats and dogs undergoing oral therapy with terbinafine or griseofulvin. M. canis comprised 92% of isolates; other species included Microsporum gypseum and Trichophyton mentagrophytes. Minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of terbinafine and griseofulvin were determined by broth macrodilution assay. Terbinafine was highly active against all three species with MIC90< or =0.03 microg ml(-1), in agreement with published data. However, terbinafine exhibited primary cidal activity against 66% of Microsporum isolates (n = 275) in contrast to the almost complete cidal effect in Trichophyton (n = 18). Griseofulvin was significantly less active than terbinafine (MIC90 = 4 microg ml(-1)) but had a primary cidal action on about 40% of the isolates. The data were analysed for changes in MIC and MFC during the course of therapy, which could be indicative for development of acquired resistance. Oral treatment of 37 animals with terbinafine for up to 39 weeks caused no increase in MIC or MFC of terbinafine, either in individual patients or in the whole group.

Development of a mouse model to determine the systemic activity of potential flea-control compounds

Probe studies were performed to determine if the cat flea (Ctenocephalides felis), the most common ectoparasite of companion animals, will feed on laboratory mice and, if so, to incorporate this into a small animal assay to detect systemically active compounds. Consequently, a protocol was developed which incorporated acepromazine maleate to temporarily sedate various strains of mice and allow fleas a window of time to feed undisturbed. For validation of the model, CD-1 mice were dosed per os with seven known insecticides at 30, 10 and 1mg/kg. Mice were sedated with 0.0125 ml acepromazine maleate intraperitoneally, and infested with fleas. After 2h, fleas were removed, one-third were examined immediately to confirm the occurrence of feeding, and 77% were found to have ingested a blood meal. The remaining fleas were incubated for 24h to determine mortality. Nitenpyram, the active ingredient in Capstar, was highly active (>94%) at 1mg/kg. Selamectin, the active ingredient in Revolution, was very active (86%) at 10mg/kg, but inactive at 1mg/kg. Fipronil, the active ingredient of Frontline Topspot, was very active (83%) at 30 mg/kg, moderately active (54%) at 10mg/kg and inactive at 1mg/kg. Cythioate, the active ingredient in Proban, and nodulisporic acid, a recently discovered oral insecticide, were moderately active (64 and 55%, respectively) at 10mg/kg, but both were inactive at 1mg/kg. Lufenuron and ivermectin exhibited no efficacy at any level tested. These findings suggest that this mouse model can effectively identify systemic flea-control leads and, subsequently, reduce the use of large animals in research.

DNA vaccination against feline calicivirus infection using a plasmid encoding the mature capsid protein

Feline calicivirus (FCV), a member of the diverse family Caliciviridae, is a respiratory and oral pathogen of cats. Although conventional FCV vaccines are available, there are some safety and efficacy problems associated with their use. The potential of DNA vaccination against FCV infection was therefore explored. Four cats were inoculated intramuscularly with three 100 microg doses, 2 weeks apart, with a plasmid (pF9VAC) containing the mature capsid protein gene of FCV strain F9. Four control cats received the same plasmid lacking the FCV gene insert. All eight cats showed clinical signs following heterologous challenge with FCV strain LS027. However, rectal temperatures and general clinical sign scores were significantly lower in vaccinates compared to controls, and there was a marked difference in ulcer distribution between the two groups. Although no serological responses were detected in either group prior to challenge, post-challenge titres in the vaccinated group were generally higher. The results indicate that partial protection against a calicivirus is possible by DNA vaccination but that other approaches to enhance efficacy such as the use of cytokine genes or prime-boost protocols may also be required.

Veterinary Products Committee working group report on feline and canine vaccination

* The working group was set up by the Veterinary Products Committee in response to current concern in both the public domain and in the scientific community about possible health risks related to the routine vaccination of cats and dogs. The working group concluded that vaccination plays a very valuable role in the prevention and control of the major infectious diseases in cats and dogs. Although adverse reactions to vaccination, including lack of efficacy, occasionally occur, the working group concluded that the overall risk/benefit analysis strongly supports their continued use. * Although for some diseases there is evidence of a longer duration of immunity following vaccination than the one year which is typically recommended on the product literature, there is currently insufficient information to propose revaccination intervals other than those proposed by the manufacturer and approved by the regulatory process. * Notwithstanding this, in view of the occasional occurrence of adverse reactions, the working group recommends that the product literature indicates that the regime for booster vaccinations is based on a minimum duration of immunity rather than a maximum. The working group further recommends that the product literature should state that a risk/benefit assessment should be made for each individual animal by the veterinary surgeon in consultation with the owner with respect to the necessity for each vaccine and the frequency of its use. * The evidence suggests that cats appear to be susceptible to the occasional development of sarcomas at sites of injection and there is some further evidence to suggest that, although other products may be involved, this may be more associated with the use of vaccines containing aluminium-based adjuvants. The working group therefore recommends that a generic warning to this effect should appear on the product literature for all feline vaccines administered by injection. The working group also highlighted the need for professional and educational bodies in the UK to bring to the attention of veterinary practitioners appropriate methods for prevention, diagnosis and treatment of this serious condition. * The working group considered in depth the monitoring of adverse reactions, including the advantages and disadvantages of surveillance schemes. A range of options for carrying out further epidemiological (analytical) studies was also considered. However, the working group emphasised that surveillance schemes, and the UK Veterinary Medicines Directorate (VMD) Suspected Adverse Reaction (SAR) Surveillance Scheme in particular, provided a very valuable resource. The large database within the VMD scheme (collected since 1985) was analysed as part of this report. Figures were derived in terms of incidence (reporting rate) of certain clinical signs per 10,000 doses, and risk factors as identified by statistical analysis. However, due to a number of constraints, the analysis was not fully comprehensive and the interaction of possible risk factors was not determined. * Product-related control charts were developed in order to detect changes in incidence rates of adverse reactions (per 10,000 doses sold) both within and between different vaccines. Such charts provide a powerful way to detect changing trends in incidence and, when used in conjunction with product characteristics, they may identify possible causes. In general, the data showed that the incidence of adverse reactions to cat and dog vaccines per 10,000 doses of product sold was relatively low. Although under-reporting is a feature of such surveillance schemes, it does appear that, overall, vaccination of cats and dogs should be considered safe and effective. * Finally, the working group was conscious, while preparing this report, of the extensive media coverage that has been given to the issue of the safety of human vaccines, in particular the mumps, measles and rubella (MMR) vaccine. The working group emphasises that the conclusions and recommendations included in this report relate only to the vaccines used in cats and dogs. The issues identified are specific to the diseases and species examined and no attempt should be made to draw analogous conclusions in relation to vaccines administered to humans.

Recombinant feline herpesvirus type 1 expressing Toxoplasma gondi ROP2 antigen inducible protective immunity in cats

In order to investigate whether a recombinant viral vaccine composed of a feline herpesvirus type 1 (FHVI) vector and an immunogenic antigen of Toxoplasma gondii can induce a protective immunity in cats, a recombinant FHV1 expressing ROP2 antigen of T. gondii was prepared. We introduced a DNA fragment encoding 1-538 amino acid residues of ROP2 precursor into FHV1 genome under the control of a cytomegalovirus promoter. The recombinant FHV1 (FHV/ROP2) successfully expressed a 59 kDa antigen that was recognized by anti-ROP2 antibodies. Vaccination of cats with FHV/ROP2 induced serum IgG recognizing the native antigen. Moreover the antibodies inhibited the in vitro invasion of tachyzoites. The vaccination also accelerated the IgG response after T. gondii infection and reduced brain parasite load in cats.

Dietary L-carnitine supplementation in obese cats alters carnitine metabolism and decreases ketosis during fasting and induced hepatic lipidosis

This study was designed to determine whether dietary carnitine supplement could protect cats from ketosis and improve carnitine and lipid metabolism in experimental feline hepatic lipidosis (FHL). Lean spayed queens received a diet containing 40 (CL group, n = 7) or 1000 (CH group, n = 4) mg/kg of L-carnitine during obesity development. Plasma fatty acid, beta-hydroxybutyrate and carnitine, and liver and muscle carnitine concentrations were measured during experimental induction of FHL and after treatment. In control cats (CL group), fasting and FHL increased the plasma concentrations of fatty acids two- to threefold (P < 0.0001) and beta-hydroxybutyrate > 10-fold (from a basal 0.22 +/- 0.03 to 1.70 +/- 0.73 after 3 wk fasting and 3.13 +/- 0.49 mmol/L during FHL). In carnitine-supplemented cats, these variables increased significantly (P < 0.0001) only during FHL (beta-hydroxybutyrate, 1.42 +/- 0.17 mmol/L). L-Carnitine supplementation significantly increased plasma, muscle and liver carnitine concentrations. Liver carnitine concentration increased dramatically from the obese state to FHL in nonsupplemented cats, but not in supplemented cats, which suggests de novo synthesis of carnitine from endogenous amino acids in control cats and reversible storage in supplemented cats. These results demonstrate the protective effect of a dietary L-carnitine supplement against fasting ketosis during obesity induction. Increasing the L-carnitine level of diets in cats with low energy requirements, such as after neutering, and a high risk of obesity could therefore be recommended.