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Objective—

To determine, by use of a reverse transcriptase-polymerase chain reaction (RT-PCR) test, patterns of fecal shedding of feline coronavirus among cats.

Design—

Prospective observational study.

Animals—

275 purebred cats from 6 private catteries and 40 specific-pathogen-free (SPF) laboratory-reared cats.

Procedure—

40 SPF cats were experimentally inoculated with crude fecal extract containing feline enteric coronavirus (FECV). Fecal and plasma samples were collected every 4 days and evaluated by use of RT-PCR and indirect immunofluorescence assays, respectively, to correlate RT-PCR results with fecal infectivity and to determine patterns of FECV shedding and anti-FECV IgG production in acutely infected cats. The 275 cats in private catteries were monitored for 1 year. Fecal and blood samples were collected every 1 to 3 months and assayed by use of RT-PCR and serologic tests to determine patterns of coronavirus shedding and cofactors for high frequency shedding.

Results—

Results of the RT-PCR test in SPF cats were directly correlated with fecal extract infectivity. Overall, 370 of 894 (41%) fecal samples collected from cattery and shelter cats contained infectious levels of coronavirus. Of 121 cats from which multiple samples were collected, 11 never shed virus and 35, 65, and 10, respectively, shed virus with low, moderate, and high frequency. High frequency shedding was associated with age and cattery of origin, but not with sex or concurrent disease. Stress associated with parturition and lactation did not induce shedding in queens. Kittens did not shed coronavirus before they were 10 weeks old, even when nursed by shedding mothers.

Clinical Implications—

A large proportion of cats in multiple-cat environments shed coronavirus at any given time, but most undergo cycles of infection and shedding, recovery, and reinfection. Infection is acquired from chronically shedding cats and from infectious cats undergoing transient primary infection. Chronically shedding cats cannot be identified on the basis of antibody titer or signalment, but must be identified on the basis of the results of serial fecal RT-PCR tests. (J Am Vet Med Assoc 1997;210:1307–1312)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate the ability of lufenuron to control cat flea (Ctenocephalides felis felis) populations on dogs under conditions simulating a naturally infested home environment.

Design

2 treatment and 2 control groups of dogs. Treated dogs received lufenuron in tablet form monthly, and controls received excipient. Dogs had unrestricted access to indoor (carpeted) and outdoor (grassy) environments in which self-propagating flea populations had been established.

Animals

17 adult female Beagles.

Procedure

Dogs were monitored for 77 days after initial infestation with fleas and 70 days after initial treatment. Efficacy of the drug was calculated on the basis of absolute reduction in flea counts and as a percentage of control.

Results

Lufenuron administration caused a statistically significant (P < 0.05) reduction in flea burdens in treated dogs, compared with controls. Initiation of treatment 7 days after infestation resulted in 75% control of F1-generation and 97% control of F2-generation fleas over a 70-day posttreatment period.

Conclusions

Lufenuron was highly effective in reducing flea populations on dogs. The time required for control will vary with the duration (generation time) of the flea reproductive cycle and, hence, the geographic area in which the product will be used. The experimental results are most relevant to use of the product for control of an existing flea population in the Midwest. (Am J Vet Res 1996;57:502–504)

Free access
in American Journal of Veterinary Research

SUMMARY

Objective

To compare the effect of monthly treatments with imidacloprid (an adulticide) or lufenuron (an insect development inhibitor) for protecting cats against Ctenocephalides felis felis in a simulated home environment.

Animals

3 matched groups of 4 cats each.

Procedure

A self-propagating flea life cycle continuously exposing cats to ‘natural’ infestation was established in 3 pens. Small artificial infestations were later superimposed to mimic the effect of a cat roaming outdoors and acquiring extraneous fleas. One pen housed an untreated control group, and the other 2 pens housed cats treated every 28th day with an imidacloprid spot-on formulation or lufenuron suspension, respectively. Flea counts were performed at 14-day intervals for 112 days.

Results

Flea numbers increased on control cats around day 42 when mean counts on cats in the imidacloprid and lufenuron groups decreased by 100 and 86.8 percent, respectively. Fleas were not found on any imidacloprid-treated cat, but lufenuron-treated cats were consistently parasitized.

Conclusions

Imidacloprid administered at monthly intervals maintained flea burdens below the limit of detection, whereas clinically important flea populations developed in the lufenuron treatment pen.

Clinical Relevance

Results from this experimental model suggest that flea populations within a home may be controlled by carefully timed on-host treatments with potent long-acting insecticides such as imidacloprid. (Am J Vet Res 1997;58:1260–1262)

Free access
in American Journal of Veterinary Research

Abstract

Twenty-four, adult, female Beagles were arranged by body weight from greatest to least and allocated to 2 groups of 12 dogs, using random numbers. Dogs were housed collectively in 2 adjacent metal buildings, each divided into 4 rooms measuring 2.1 × 3.7 m. Each room was paneled and carpeted and had an access door to the outside with a connecting run that measured 2.1 × 9.1 m. Each run had a surface consisting of 5 cm of pea gravel overlaying 5 cm of sand, and was partially covered by an awning that provided shade at its proximal end. For placement in room/run units, dogs in each of the treated and control groups were allotted to 4 subgroups of 3 dogs each. Each subgroup of dogs was placed in a separate room/run unit. Units containing treatment or control subgroups were alternated to avoid placing identically treated subgroups adjacent to each other. Dogs of subgroups A, C, E, and G were treated with lufenuron monthly at a minimal target dosage of 10 mg/kg of body weight; those of subgroups B, D, F, and H were treated with excipient tablets. Dogs were treated on study days 7, 37, 68, and 98. Each dog was infested with 100 newly emerged, unfed, insectary-reared, adult Ctenocephalides felts on each of study days 0 and 2. Thereafter, infestations on all dogs were dependent on continued development of fleas either in the indoor or outdoor environment. Numbers of fleas on each of the treated and control dogs were determined, using a nondestructive counting technique on days 6, 14, 21, 28, 35, 56, 70, 84, 98, 112, and 119. On study day 21 and on each collection day thereafter, numbers of adult fleas recovered from treated dogs were significantly (P < 0.05) fewer than those recovered from control dogs. Proportion reduction of fleas on treated vs control dogs exceeded 90% by study day 35 and 95% by study day 56. Efficacies exceeded 95% on all remaining study days except days 98 (94.4%) and 119 (90%). Results of this study indicate that control of flea populations can be achieved in treated dogs approximately 4 to 5 weeks after initial treatment with lufenuron, and that continued monthly treatments will maintain effective control of flea infestations. Adverse reactions or side effects to treatment with lufenuron were not observed in dogs after treatment at any time throughout the study.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To genetically type Campylobacter jejuni isolates from broiler houses or the external environment to identify the source of Campylobacter organisms in broiler chickens.

Sample Population—Environmental samples associated with broiler chickens, in commercial grow-out houses.

Procedure—Polymerase chain reaction (PCR) was used to amplify flaB, and the amplicon was digested with Sau3A to create a restriction fragment length polymorphism assay; PCR was also used to detect a transcribed spacer region in the 23S rRNA gene.

Results—Isolates possessing a 23S spacer region were more prevalent outside broiler houses than inside. Houses that had previously contained chickens or lacked biosecurity procedures were more likely to contain isolates possessing the 23S spacer. One house contained only isolates possessing the spacer, whereas an adjacent house contained only isolates lacking the spacer. The flaB type detected in broiler houses was different from the type detected in the environment; however, many isolates within the broiler houses contained untypable flaB genotypes.

Conclusions and Clinical Relevance—Most isolates from within houses were genetically distinct from isolates from outside houses that were examined by bacteriologic culture, suggesting an undetected source of C jejuni. Detection of isolates containing the 23S spacer appeared to be an indicator of environmental contamination of the houses. The observation of completely different C jejuni genetic types simultaneously within adjacent houses suggests that some types do not compete successfully during the grow-out period. In addition, the diversity of genotypes identified within broiler houses indicates the complexity of the ecologic features of C jejuni in the chicken environment. (Am J Vet Res 2001;62:190–194)

Full access
in American Journal of Veterinary Research

these housing environments. Additionally, we hypothesized that there would be differences in echocardiographic parameters between animals of different size, sex, restraint method (anesthesia or manual restraint), and echocardiographic approach (ventral

Open access
in American Journal of Veterinary Research

SUMMARY

A method was developed to evaluate frequent milking as a means of controlling intramammary infection. An artificial intramammary environment was used to determine growth responses of Escherichia coli (P4) to natural changes in the mammary gland resulting from bacterial invasion. Physical conditions manipulated in this model were growth medium, temperature, and oxygen tension. Mathematical modeling was then incorporated to generate predictions concerning growth dynamics of the organism when milking frequency was changed. To test accuracy of the model, initial predictions were derived from bacterial growth data in which E coli was incubated in tryptose soy broth for 12 hours at 37 C and Po2 equal to 23.3 mm of Hg. These predictions matched closely with experimental data in which 12-, 4-, and 2-hour milking intervals were simulated in the artificial intramammary environment. The mathematical model was then used to characterize growth rate data from in vitro experiments in ultra-high temperature- treated milk and in vivo experimental infection data generated with E coli (P4). Predictions generated from this model suggested that increasing milking frequency to 4 or 6 times daily controls growth of E coli for a prolonged period and that 12 times daily milking may lead to elimination of the bacterium.

Free access
in American Journal of Veterinary Research

for student surgical experience. 3–6 The rates and types of surgical complications associated with procedures performed by veterinary students in shelter environments are important to determine so that specific concerns associated with such training

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

Objective

To investigate the relation between cardiac output (CO) and peripheral (fetlock) temperature (PT) and core-peripheral (rectal-fetlock) temperature difference (CPTD) in dehydrated calves housed in a thermoneutral environment.

Animals

28 male dairy calves 3 to 10 days old.

Procedure

Severe dehydration and watery diarrhea were induced by administering diuretics (furosemide, hydrohlorothiazide, spironolactone) and sucrose solution. Cardiac output was measured by means of thermodilution, core temperature was determined by placing a digital thermometer in the rectum, and PT was measured by taping a thermistor to the left hind fetlock and insulating the thermistor from ambient air.

Results

In thermoneutral ambient temperatures (10 to 24 C), PT and CPTD were constant and independent of CO at normal or high CO values but were linearly dependent on CO below a critical value (78% of normal CO output). Regression equations were developed that predicted CO from measured PT or CPTD. At ambient temperatures below the lower critical temperature for neonatal calves (8 to 10 C), normal values for PT and CPTD in healthy calves were significantly different from those at thermoneutral ambient temperatures.

Conclusions and Clinical Relevance

Peripheral temperature and CPTD are practical, noninvasive, and inexpensive but only moderately useful methods for predicting CO in hemodynamically stable calves housed in a thermoneutral environment. Thus, these parameters are of some value in daily monitoring of the response to treatment and in determining need for IV fluid administration in dehydrated calves housed at a dry still-air temperature of 10 to 24 C but are of minimal to no value in calves housed at < 10 C. (Am J Vet Res 1998;59:874–880)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association