Efficacy of vaccination in preventing giardiasis in calves

The objective of this study was to evaluate the efficacy of a vaccine in the prevention of Giardia duodenalis infection in calves. Six 2-week old calves were vaccinated subcutaneously with a sonicated G. duodenalis trophozoite vaccine. Six 2-week old control calves received a subcutaneous injection of sterile phosphate-buffered-saline mixed with adjuvant. Injections were repeated after 28 days. Eleven days after the second injection, calves were challenged orally with 1x10(5) purified G. duodenalis cysts from a naturally infected calf. Throughout the study, fecal samples were collected at regular intervals and examined for the presence of G. duodenalis cysts. Blood samples were collected weekly until G. duodenalis challenge and bi-weekly following challenge. Calves were euthanized 14 days after challenge and G. duodenalis trophozoites within the small intestines were enumerated. Serum antibody titers were significantly higher in vaccinated compared to non-vaccinated calves. Vaccinated calves tended to excrete more G. duodenalis cysts in their feces than non-vaccinated calves. The number of trophozoites in the small intestine was not different between vaccinated and non-vaccinated calves. Changes consistent of moderate enteritis were found in the intestines of one vaccinated and one non-vaccinated calf. Despite a serological immune response following vaccination, this vaccine was not efficacious in preventing giardiasis or reducing cyst shedding in calves.     

Efficacy of a combination febantel-praziquantel-pyrantel product, with or without vaccination with a commercial Giardia vaccine, for treatment of dogs with naturally occurring giardiasis

OBJECTIVE: To determine efficacy of treatment with a combination febantel-praziquantel-pyrantel product, with or without vaccination with a commercial Giardia vaccine, in dogs with naturally occurring giardiasis. DESIGN: Prospective trial. ANIMALS: 16 Beagles naturally infected with Giardia duodenalis. PROCEDURES: During phase 1, 6 dogs were treated with the parasiticide for 3 days (4 were also vaccinated). Four weeks later, all 6 dogs were treated with the parasiticide again for 5 days and were bathed and moved to clean cages after the last treatment (phase 2). Nine dogs were treated with the parasiticide for 3 (n = 4) or 5 (5) days and bathed and moved to clean cages after the last treatment (phase 3). Fecal samples were collected twice weekly for 24 days after treatment and tested for cysts with a quantitative zinc sulfate flotation technique and for Giardia antigen with an immunoassay. RESULTS: Dogs in phase 1 were all shedding cysts again by day 24. In phase 2, only 1 dog shed cysts after treatment, and shedding was transient (day 17). In phase 3, neither cysts nor antigen was detected in fecal samples from 2 of 4 dogs treated for 3 days and 4 of 5 dogs treated for 5 days. In 18 of 57 (31.6%) fecal samples, cysts were seen, but results of the immunoassay were negative. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that when a combination febantel-praziquantel-pyrantel product is used to treat dogs with giardiasis, bathing and changing the environment after treatment may be more important in preventing recurrence than duration of treatment.     

The zoonotic significance and molecular epidemiology of Giardia and giardiasis

The taxonomy and molecular epidemiology of Giardia and Giardia infections are reviewed in the context of zoonotic and waterborne transmission. Evidence to support the zoonotic transmission of Giardia is very strong, but how frequent such transmission occurs and under what circumstances, have yet to be determined. Zoonotic origin for waterborne outbreaks of Giardia infection appears to be uncommon. Similarly, livestock are unlikely to be an important source of infection in humans. The greatest risk of zoonotic transmission appears to be from companion animals such as dogs and cats, although further studies are required in different endemic foci in order to determine the frequency of such transmission.     

Genotypic analysis of Giardia duodenalis in domestic cats

BACKGROUND: Giardia duodenalis is an intestinal flagellated protozoan that affects many mammalian species often causing severe diarrheal disease. Several different genotypes have been identified (Assemblages A-G). Most isolates recovered from domestic cats have been assigned to either Assemblage A, the zoonotic form of the parasite, or Assemblage F, identified thus far only in cats. Genotypic variation within G. duodenalis may influence clinical presentation and course of disease. Therefore, host-adapted genotypes may not be responsible for diarrheal disease (eg, Assemblage F in cats). HYPOTHESIS: Multiple Giardia genotypes will be present in domestic cats, including Assemblage F, which will not be correlated with clinical signs. ANIMALS: 250 domestic cats from eastern Mississippi and northwestern Alabama. METHODS: Prevalence survey. Fecal samples evaluated for cysts using a centrifugation concentration technique and a commercially available direct immunoflourescent antibody kit. Giardia isolates were characterized by PCR amplification and sequencing of the glutamate dehydrogenase gene. RESULTS: Both Assemblage A-I (6/17) and Assemblage F (11/17) were identified. Although Assemblage was significantly associated with age and housing, no association was detected between Assemblage and a variety of other factors including the presence of gastrointestinal signs (acute vomiting, diarrhea, and constipation). CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of diarrhea in domestic cats with Giardia cannot be used as a predictor of the presence of zoonotic genotypes in animals within the study area. Although Assemblage A was associated with age and housing, veterinarians should consider any isolation of Giardia from domestic cats as potentially zoonotic.     

Efficacy of selamectin in the treatment of naturally acquired cheyletiellosis in cats

The purpose of this study was to evaluate the efficacy of a topical formulation of selamectin in the treatment of cheyletiellosis in cats. Fifteen adult domestic cats from the same household with naturally occurring Cheyletiella sp. infestation were enrolled in the study. On each cat, 45 mg of selamectin was applied on days 0, 30, and 60. No other treatment or environmental decontamination was performed during the trial. On days 0, 30, 60, and 120, all cats were examined, epidermal debris was collected over the dorsal area of the body with flea combs for microscopic examination, and fecal flotations were done. Clinical signs had subsided by day 60 in all 15 cats and no signs of recurrence were apparent on follow-up 1 year later. All epidermal and fecal samples were negative by day 60. No adverse reactions were observed. Under the conditions of our study, topical selamectin was a practical and well-tolerated means of treatment for cheyletiellosis in cats.     

Efficacy and toxicosis of VELCAP-C treatment of lymphoma in cats

Background: Lymphoma is the most common malignancy affecting cats. A protocol employing vincristine, l -asparaginase, cyclophosphamide, doxorubicin, and prednisone (VELCAP-S) is effective and well tolerated in dogs with lymphoma. A 24-week variation of this protocol (VELCAP-C) was developed for treatment of cats.
Hypothesis: That VELCAP-C will result in survival times for cats with lymphoma that are similar to those obtained when cats are treated with a protocol that includes fewer chemotherapy agents.
Animals: Sixty-one cats with lymphoma.
Methods: Retrospective study. Outcomes evaluated were response to VELCAP-C therapy, toxicosis, and survival time. The effect of signalment, staging, CBC, and serum chemistry profile and dosage on these outcomes was examined.
Results: Six cats (10%) completed the protocol with a median survival of 1189 days. Forty-three percent (23 of 61) of the cats achieved complete response (CR) with a median survival time of 62 days. Cats that required a dose reduction of any drug during induction were more likely to achieve CR. Weight loss and hepatomegaly at diagnosis were negatively associated with response to treatment. Increased lactate dehydrogenase (LDH) serum activity at the time of initial treatment correlated with decreased survival times.
Conclusions and Clinical Importance: This multi agent protocol did not provide improved survival over historical data using protocols with fewer agents. Serum LDH activity levels might provide useful prognostic information for cats with lymphoma.     

Giardia duodenalis in colony stray cats from Italy

Giardia duodenalis is the most common intestinal protozoan in humans and animals worldwide, including eight morphologically identical assemblages, infecting pets, livestock, wildlife and human beings. Assemblages A and B are those with the higher zoonotic potential, and they have been detected in several mammals other than humans; the others (C to H) show a higher host specificity. Cats can harbour both the specific Assemblage F and the zoonotic ones A and B. Several studies have been carried out on G. duodenalis genotypes in cats; however, the role of this species in the epidemiology of giardiasis is still poorly understood. In this scenario, the present study carried out the detection and genetic characterization at sub-assemblage level of G. duodenalis from colony stray cats in central Italy. In the period 2018–2019, 133 cat faecal samples were analysed for the presence of G. duodenalis cysts by a direct immunofluorescence assay. Positive samples were subsequently subjected to molecular analyses for assemblage/sub-assemblage identification. Forty-seven samples (35.3%) were positive for G. duodenalis cysts by immunofluorescence. G. duodenalis DNA was amplified at SSU-rDNA locus from 39 isolates: 37 were positive for zoonotic Assemblage A and 2 showed a mixed infection (A + B). Positive results for the β-giardin gene were achieved for 25 isolates. Sequence analysis revealed 16 isolates belonging to Sub-assemblage AII and 8 to Sub-assemblage AIII. One isolate resulted as ambiguous AI/AIII. Large sequence variability at the sub-assemblage level was detected, with several double peaks and mutations, making complex a proper isolate allocation. When compared with previous studies, the 35.3% prevalence of G. duodenalis in cats reported in the present article was surprisingly high. Moreover, all positive cats resulted to be infected with zoonotic assemblages/sub-assemblages, thus indicating stray cats as a possible source of human giardiasis and highlighting the sanitary relevance of cat colonies in the study area.     

Evaluation of fenbendazole for treatment of Giardia infection in cats concurrently infected with Cryptosporidium parvum

OBJECTIVE: To determine whether fenbendazole effectively eliminates Giardia organisms from chronically infected cats that have a concurrent Cryptosporidium parvum infection. ANIMALS: 16 clinically normal cats. PROCEDURE: Eight cats with chronic concurrent Giardia and C parvum infections received fenbendazole (50 mg/kg, PO, q 24 h) for 5 days (treatment-group cats). Feces from each cat were collected and processed 3 days weekly for 23 days after treatment. By use of an immunofluorescent assay for detection of Giardia lamblia cysts and C parvum oocysts, organism numbers were counted and scored. Fecal results from treatment-group cats were compared with those of 8 untreated cats with Giardia infection but no C parvum infection (control-group cats). RESULTS: Four of 8 treatment-group cats had consistently negative results for Giardia infection after treatment. These 4 cats had consistently positive results for C parvum oocysts prior to treatment and consistently negative results after treatment. One treatment-group cat had positive results for cysts on all fecal samples, and 3 treatment-group cats had 1 to 3 negative results and then resumed shedding large numbers of cysts; each of these cats had consistently positive results for C parvum oocysts. When compared with control-group cats, treatment-group cats shed less Giardia cysts during week 1 after treatment but not during week 2. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of fenbendazole decreases Giardia cyst shedding to less than detectable numbers in some cats. In our study, persistent C parvum infection may have been associated with failure of fenbendazole to eliminate Giardia infection.     

Giardia infection of cats and dogs in New Zealand

Giardia intestinalis is a pathogenic protozoan which infects humans and a wide range of animal hosts, including cats and dogs⁽¹⁾. However, the status of animals in New Zealand with respect to Giardia infection has not received much attention, so we undertook a preliminary study of cats and dogs in Palmerston North and Hamilton to determine the prevalence of infection, as indicated by the presence of cysts in faeces.     

High prevalence of Giardia detected in cats by PCR

Microscopy, PCR and a Giardia CELISA test were used to determine the prevalence of Giardia in 40 faecal samples obtained from domestic cats in the Perth metropolitan area. A prevalence of 5, 80 and 60% was found by the tests, respectively. The results show that more sensitive techniques such as PCR may be necessary, and may yield more reliable results, in the detection of low levels of Giardia in domestic cats.     

Impact of Giardia vaccination on asymptomatic Giardia infections in dogs at a research facility

Feces were collected from 107 asymptomatic dogs at a research facility in Guelph, Ontario. The prevalence of Giardia infection was 11% (12/107). To assess the effectiveness of Giardia vaccination for treatment of Giardia carriage, 9 additional asymptomatic Giardia antigen-positive dogs were brought into the facility. The Giardia antigen-positive dogs were then randomly allocated to receive either vaccine (n = 10) or a saline placebo (n = 10). Feces were then monitored monthly for 6 mo for Giardia antigen and Giardia cysts. At weeks 4, 8, 12, and 16 following vaccination, there were more Giardia-positive dogs in the vaccinated group (10/10, 9/10, 9/10, 8/10, respectively) compared with the controls (7/10, 7/10, 8/10, 4/10, respectively). At week 20, an equal number of dogs (5/10) were Giardia positive, and at week 24, fewer dogs were positive in the vaccinated group than in the control group (2/10 versus 5/10, respectively). However, there was no significant difference between the 2 groups. Vaccination was, therefore, not an effective treatment for asymptomatic canine Giardia infections in this setting.     

Metronidazole for the treatment of feline giardiasis

There are several drugs available for the treatment of giardiasis in cats, including metronidazole. The purpose of this study was to determine whether metronidazole benzoate administered at a dose of 25 mg/kg, orally, twice a day for 7 days lessens or eliminates Giardia cyst shedding in cats with chronic infection. Twenty-six, adult, laboratory-reared cats were used in this study. Sixteen cats had been inoculated orally with cysts of a human Giardia sp. isolate and had completed a Giardia vaccine study in one animal holding room. The other ten cats were infected with the same Giardia sp. presumably by contamination from the adjacent room where the Giardia vaccine study cats were located. From each cat, a fecal sample was collected within 1 week of the start of treatment and then every 2 to 4 days for 15 days after treatment was completed. Fecal samples were analyzed for the presence of Giardia cysts using a commercially available direct immunofluorescence test (IFA). Clinical signs of drug toxicity were not detected during the study.     

Efficacy of iopanoic acid for treatment of spontaneous hyperthyroidism in cats

Iopanoic acid is an iodine containing oral cholecystographic agent that has been used to treat hyperthyroidism in humans and has recently been evaluated in an experimental model of feline hyperthyroidism. The aim of this study was to evaluate the efficacy of iopanoic acid in cats with spontaneous hyperthyroidism. Eleven cats were included in the study. Eight were treated initially with 50mg orally q 12h and three were treated with 100mg orally q 12h. Prior to treatment (baseline) and at 2, 4, and 12 weeks of treatment, owner questionnaires, physical exams, complete blood count, biochemistry analyses, and T(3) and T(4) concentrations were evaluated. The mean serum T(3) concentration decreased with treatment at all time periods compared to baseline. Mean T(4) concentrations were increased at weeks 4 and 12 compared to baseline. Five cats had a partial response during the initial 4 weeks of therapy, but the effects were transient and no significant improvements in clinical signs or physical exam findings were noted at any time period. Results suggest that iopanoic acid may be beneficial for acute management of thyrotoxicosis in some cats, but is not suitable for long-term management.     

Efficacy and safety of transdermal methimazole in the treatment of cats with hyperthyroidism

The objective of this study was to determine whether transdermal methimazole was as safe and effective as oral methimazole for the control of hyperthyroidism in cats. Forty-seven cats with newly diagnosed hyperthyroidism were randomized to receive either transdermal methimazole in pluronic lecithin organogel (PLO; applied to the inner pinna), or oral methimazole (2.5 mg q12h for either route). Cats were evaluated at weeks 0, 2, and 4 with a physical exam, body weight determination, CBC, biochemical panel, urinalysis, measurement of total levothyroxine (T4) concentration, indirect Doppler blood pressure determinaiton, and completion of an owner questionnaire. Data between the 2 groups and over time were compared by nonparametric methods. Forty-four cats followed the protocol (17 oral and 27 transdermal). Significantly more cats treated with oral methimazole had serum T4 concentrations within the reference range after 2 weeks (14 of 16 cats) compared to those treated by the transdermal route (14 of 25; P = .027). This difference was no longer significant by 4 weeks of treatment (9 of 11 for oral versus 14 of 21 for transdermal), possibly because of inadequate numbers evaluated by 4 weeks. Cats treated with oral methimazole had a higher incidence of gastrointestinal (GI) adverse effects (4 of 17 cats) compared to the cats treated with transdermal methimazole (1 of 27; P = .04), but no differences were found between groups in the incidence of neutropenia, hepatotoxicity, or facial excoriations. Although the overall efficacy of transdermal methimazole is not as high as that of oral methimazole at 2 weeks of treatment, it is associated with fewer GI adverse effects compared to the oral route.     

Efficacy of digoxin for treatment of cats with dilated cardiomyopathy

The role of digoxin in treatment of cats with dilated cardiomyopathy and other forms of myocardial failure is unclear. We evaluated the chronotropic and inotropic effects of digoxin by comparing baseline, noninvasive indices of cardiac performance with those obtained after 9 +/- 1.3 (mean +/- SEM) days of digoxin treatment in 6 cats with heart failure attributable to dilated cardiomyopathy. Two-dimensionally directed, M-mode echocardiography and electrocardiography were used to determine left ventricular shortening fraction, preejection period (PEP), ejection time (LVET), PEP to LVET ratio, velocity of circumferential fiber shortening, electromechanical systole, heart rate, and PR interval. Treatment consisted of administration of furosemide (mean dosage, 2.4 mg/kg of body weight/day), digoxin in tablet form (approximately 0.01 mg/kg, q 48 h), aspirin (80 mg, q 48 h), and a commercial low-salt diet. In addition, 2 cats were administered short-term, low-dose fluids IV, and 2 were given taurine supplementation at rates of 500 and 1,000 mg/day. Other off-loading or inotropic agents were not administered. Therapeutic or toxic serum digoxin concentration was achieved in all cats. Significant (P less than 0.05) improvement was detected in mean values for shortening fraction, PEP, PEP to LVET ratio, and velocity of circumferential fiber shortening. Mean electromechanical systole and LVET did not change significantly. Improvement, as assessed by indices of cardiac function, was documented in 4 of the 6 cats treated with digoxin, including the 2 cats given taurine supplementation. In the cats given taurine, positive inotropic effect was observed prior to the time when taurine-induced improvement in ventricular function is detectable.(ABSTRACT TRUNCATED AT 250 WORDS)