Comparison of viability and infectivity of Cryptosporidium parvum oocysts stored in potassium dichromate solution and chlorinated tap water

The present study was undertaken to compare the viability and infectivity of Cryptosporidium parvum oocysts that had been stored for 1, 4, 7, 10, 13, 16, 20, 25 and 30 months at 4 degrees C in 2.5% potassium dichromate (Cr) or chlorinated tap water, respectively. An excystation protocol was performed in vitro to evaluate viability. One hundred and eighty female BABL/c mice were used to evaluate the infectivity of oocysts by investigating the prepatent period of C. parvum infection, the quantity of oocysts excreted, and the number of parasites that colonized the villi of the ileum. The results showed that C. parvum oocysts preserved in Cr for 1-16 months or in water for 1-13 months were capable of excystation in vitro and infection of mice. The excystation rates of oocysts and the prepatent periods in mice infected by oocysts stored in Cr and water were not significantly different (p>0.05), and there was a strong correlation between prepatent period and duration of oocyst storage (Cr: R2=0.92; water: R2=0.98). There were no significant differences in oocyst shedding from feces or parasitism of the terminal ilea of mice by Cryptosporidia between the two storage media (p>0.05). In conclusion, C. parvum oocysts may be stored at 4 degrees C in water instead of Cr for the purposes of laboratory research. However, the presence of viable C. parvum oocysts in water is a severe challenge to the drinking water treatment industry.     

Ex vivo viability of canine and feline sarcomas: a pilot study

Assay-based chemotherapeutic protocols are common in human gynecologic oncology, most notably for patients with ovarian or breast cancer. The current study examines ex vivo incubation conditions necessary for the assessment of sarcomatous tumor response to potential chemotherapeutic drugs. Slices of sarcomatous tumors were incubated in one of two culture media. Viability indices were measured and compared across time and between media. Neither medium was sufficient to support the growth of sarcomatous tumor tissue slices based on the indices studied. It is likely that sarcomatous tumors require a different approach for ex vivo assessment than their epithelial counterparts. Our long-term goal is to incubate tumor slices with chemotherapeutic agents to predict the in vivo tumor response based on the maintenance or loss of slice viability within this system.     

The quality of cryopreserved sperm collected from feline caudal epididymides stored at room temperature

On the assumption that animals of wild feline species died in the field, caudal epididymal sperm were cryopreserved following storage of the feline epididymides at 20°C for 0-24 hr, and their qualities were observed. Compared to the qualities at 0 hr, no significant differences were noted following 12 hr of storage at 20°C. On comparison of the qualities between caudal sperm cryopreserved after 24 hr storage at 4°C and after 12 hr at 20°C followed by 12 hr storage at 4°C, no significant differences were noted. These findings suggest that the cryopreserved sperm collected from epididymides of dead animals might be useful for artificial insemination if cryopreservation was performed within 12 hr exposure to ambient temperature.     

Ocular effects of topical 0.03% bimatoprost solution in normotensive feline eyes

OBJECTIVE: The current study was undertaken to evaluate the effects of topically applied bimatoprost, an ocular hypotensive lipid, on intraocular pressure (IOP) and pupil size (PS) in healthy cats. ANIMAL STUDIED: Nine European Shorthair cats free from clinically relevant ocular abnormalities were used in the study. PROCEDURES: Pretreatment baseline measurements of IOP and PS were obtained bilaterally at 8 am, 2 pm, and 8 pm for five consecutive days (days 1 to 5). Then the cats received one drop twice daily (10 am and 6 pm) of bimatoprost ophthalmic solution 0.03% (Lumigantrade mark, Allergan Inc., Irvine, CA USA), in one randomly selected eye and one drop of artificial tears in the fellow eye (control eye) for 5 days (days 6 to 10). Values for IOP and PS were obtained under the same conditions as in the pretreatment phase. The potential for ocular irritation following bimatoprost application was also evaluated. RESULTS: During the pretreatment period, the mean IOP and mean PS were not significantly different between the eyes subsequently treated with bimatoprost and those subsequently determined as controls. During the treatment period, the mean IOP in bimatoprost-treated eyes was not significantly lower than in control eyes (14.2+/-2.3 vs. 14.5+/-2.8 mmHg). Mean IOP in control eyes was not significantly changed at any time during the study period. A marked reduction of PS was seen in all bimatoprost-treated eyes, but no other clinically relevant side effects were observed. CONCLUSION: Twice daily topical applications of bimatoprost produced miosis but had no significant effect on IOP in healthy cats.     

Endocytosis of erythrocytes in vivo and particulate substances in vitro by feline neoplastic mast cells.

Clinical evidence for the phagocytic capability of neoplastic feline mast cells was provided by recognition of endocytosed erythrocytes in seven of 12 cytological smears of mast cell neoplasms, particularly in those cells collected from splenic tumors. The capability of these neoplastic mast cells to endocytose particulate substances was also studied in vitro. Evidence is presented that under cultural conditions, feline neoplastic mast cells are capable of endocytosing a variety of substances including polystyrene latex microspheres, zymosan particles, horse spleen ferritin, salmon sperm nuclei, horseradish peroxidase, and carbon particles.     

Influence of phosphate-buffered sucrose solution on early graft function in feline renal autotransplantation

Graft perfusion with cold heparinized saline has known to induce ischemia and reperfusion injury in feline kidney transplantation. In this study, the effects of phosphate-buffered sucrose solution and heparinized saline solution on early kidney graft function were compared in feline kidney autotransplantation. Perfusion of grafts with or without hypothermic storage with chilled phosphate-buffered sucrose solution prevented ischemia and reperfusion injury despite a very short ischemic time. The results of our study suggest that phosphate-buffered sucrose perfusion and storage solution should be effective to reduce ischemia and reperfusion injury despite a very short ischemic time in feline kidney transplantation.     

Prevalence of feline leukaemia provirus DNA in feline lymphomas

A significant drop in the prevalence of feline leukaemia virus (FeLV) antigenaemic cats and antigen-associated lymphomas has been observed after the introduction of FeLV vaccination and antigen-testing with removal of persistently antigenaemic cats. However, recent reports have indicated that regressively infected cats may contain FeLV provirus DNA and that lymphoma development may be associated with the presence of provirus alone. In the present study, we investigated the presence of FeLV antigen and provirus DNA in 50 lymphomas by immunohistochemistry and semi-nested polymerase chain reaction, respectively. Interestingly, almost 80% of T-cell lymphomas and 60% of B-cell lymphomas contained provirus DNA while only 21% of T-cell lymphomas and 11% of B-cell lymphomas expressed FeLV antigen. In conclusion, our results support previous hypotheses that vaccination and removal of persistently antigenaemic cats have led to a drop in FeLV antigen-expressing lymphomas. However, FeLV provirus DNA is still present in a high percentage of feline lymphomas.     

Detection of feline coronavirus antibody, feline immunodeficiency virus antibody, and feline leukemia virus antigen in ascites from cats with effusive feline infectious peritonitis

To investigate the usefulness of ascites as a material for viral tests in cats with effusive feline infectious peritonitis (FIP), we attempted to detect anti-feline coronavirus antibody, anti-feline immunodeficiency virus antibody, and feline leukemia virus antigen in ascites from 88 cats clinically suspected with effusive FIP. In each of these three viral tests, all cats positive for serum antibody/antigen were also positive for ascitic antibody/antigen, while cats negative for serum antibody/antigen were also negative for ascitic antibody/antigen. This finding indicates that ascites is useful for these viral tests.     

Carrier-state infection of feline T-lymphoblastoid cells with feline calicivirus

The susceptibility of feline T lymphocytes to feline calicivirus (FCV) in vitro was investigated using feline T-lymphoblastoid cell lines, namely MYA-1 and FL74 cells. The virus titers of supernatants in FCV-infected MYA-1 and FL74 cell cultures increased rapidly, and FCV antigens were also detected in the FCV-infected cells. There were slight differences in the molecular weights of capsid proteins expressed in FCV-infected MYA-1, FL74 and Crandell feline kidney cells. MYA-1 and FL74 cells were productively and persistently infected with FCV, and FCV antigens were observed in the FCV-infected cells for more than one month. At 3 months post infection, FCV-infected FL74 cells that stopped producing infectious FCV could be reinfected with FCV. However, no cytopathic effects were observed.     

Autoantibodies in feline hyperthyroidism

Thyroid autoantibodies have been demonstrated by indirect immunofluorescence in the sera of 10 of 29 (34 per cent) cats with hyperthyroidism. Antinuclear factor, rare in healthy cats, was found in a further four animals. Twenty-eight of the cats had a palpable goitre at first presentation. In 16 cases the goitre was unilateral, while in the others it was bilateral. Lymphocytic infiltration was present in nine of the 27 (33 per cent) thyroids examined histologically. Five of the sera gave a particularly strong reaction for thyroid antibodies. Four of these cases had bilateral goitres and lymphocytic infiltrations were found in four of the five thyroids (P less than 0.05). Twenty-one of the cats were followed up for a mean period of 11 months after operation, during which time three cats developed recurrent hyperthyroidism. Two had bilateral goitres with lymphocytic infiltration and the serum of both was strongly positive for thyroid microsomal antibodies. The third had unilateral goitre with lymphocytic infiltration and serum which was positive for antinuclear factor. In this case, the recurrence involved the lobe which had been previously operated on. Some cases of feline hyperthyroidism may be immunologically mediated and the condition is thus a potential model for some aspects of autoimmune thyrotoxicosis in man.     

Prevalences of feline leukaemia virus and feline immunodeficiency virus infections in cats in Sydney

Objective To determine prevalences of feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) infections in ‘healthy’ cats that, through acute misadventure or other circumstance, were presented to veterinary practitioners. Prevalences of FeLV and FIV in this population were compared to those in a population of predominantly sick cats. Design and procedures Serum specimens were obtained over a 2-year period from 200 cats oldeer than 1 year of age presented to veterinary clinics for routine procedures, including cat fight injuries or abscesses, vehicular trauma, neutering, dental scaling, vaccination, grooming or boarding. An additional 894 sera were obtained over approximately the same period from specimens submitted by veterinarians to a private clinical pathology laboratory, mainly from sick cats suspected of having immune dysfunction, but including some sera from healthy cats being screened prior to FeLV vaccination. FIV antibody and FeLV antigen were detected in samples using commercial enzyme immunoassays. Results Amongst 200 ‘healthy’ cats, the prevalence of FeLV infection was 0 to 2%, and the prevalence of FIV was 6.5 to 7.5%, depending on the stringency of the criteria used to define positivity. FIV infection was significantly more prevalent in cats which resided in an inner city environment (P = 0.013). Of the 894 serum specimens submitted to the laboratory by practitioners, 11/761 (1.4%) were FeLV positive, while 148/711 (20.8%) were FIV positive. The prevalence of FIV was significantly higher in these predominantly ‘sick’ cats than in cats seen for routine veterinary procedures (P < 0.00001), while there was no difference in the prevalence of FeLV (P = 0.75) Conclusions The prevalence of FeLV and FIV in healthy cats may have been substantially overestimated in some previous Australian surveys. FeLV infection would appear to be a rare cause of disease in Australian cats. The higher prevalence of FIV positivity in sick as opposed to healthy cats infers that FIV infection contributes to the development of disease.     

Onset of immunity in kittens after vaccination with a non-adjuvanted vaccine against feline panleucopenia, feline calicivirus and feline herpesvirus

The induction of a quick onset of immunity against feline parvovirus (FPV), feline herpesvirus (FHV) and feline calicivirus (FCV) is critical both in young kittens after the decline of maternal antibodies and in cats at high risk of exposure. The onset of immunity for the core components was evaluated in 8–9 week old specific pathogen free kittens by challenge 1 week after vaccination with a combined modified live (FPV, FHV) and inactivated (FCV) vaccine. The protection obtained 1 week after vaccination was compared to that obtained when the challenge was performed 3–4 weeks after vaccination. The protocol consisted of a single injection for vaccination against FPV and two injections 4 weeks apart for FHV and FCV.At 1 week after vaccination, the kittens showed no FPV-induced clinical signs or leukopenia following challenge, and after FCV and FHV challenges the clinical score was significantly lower in vaccinated animals than in controls. Interestingly, the relative efficacy of the vaccination was comparable whether the animals were challenged 1 week or 3–4 weeks after vaccination, indicating that the onset of protection occurred within 7 days of vaccination. Following the 1-week challenge, excretion of FPV, FHV and FCV was significantly reduced in vaccinated cats compared to control kittens, confirming the onset of immunity within 7 days of vaccination.     

First detection of feline bocaparvovirus 2 and feline chaphamaparvovirus in healthy cats in Turkey

Veterinary Research Communications - The pet cat’s population and the number of viruses that infect them are increasing worldwide. Recently, feline chaphamaparvovirus (FeChPV, also called...