Search Results

Abstract

Objective—To assess spatial and temporal patterns of seroprevalence among dogs in California to the causative agent of granulocytic ehrlichiosis (GE).

Sample Population—Sera of 1,082 clinically normal dogs from 54 of 59 counties in California in 1997 to 1998.

Procedure—Serum-specific IgG reactivity to Ehrlichia equi was assessed by use of an immunofluorescent antibody assay, using E equi-infected horse neutrophils as substrate. Data were analyzed, using a geographic information system. Spatial analysis of seroprevalence included first order Bayesian analysis of seroprevalence and second order analysis of clustering by K-function and Cuzick-Edwards tests. Monthly seroprevalence among dogs was examined by use of regression on monthly densities of Ixodes pacificus adults and nymphs .

Results—Seroprevalence among dogs to E equi was 8.68%. Data were seasonally bimodal with highest prevalence in winter (when adult ticks were abundant) and a secondary peak in late spring (corresponding to nymphal ticks). Humboldt County had the highest seroprevalence (47.3%), and other northern coast range counties had seroprevalence from 15 to 30%.

Conclusion and Clinical Relevance—The patchy distribution of exposure to Ehrlichia organisms is a subset of the distribution of the tick vector. This may reflect enzootic cycles or climatic or historical factors that limited the range of the disease. Dogs, horses, and humans from north coast range counties in California are at increased risk of GE. These data provide a background for assessing risk of infection in horses and dogs, depending on geographic location. Dogs may be sentinels for assessing risk of GE in humans. (Am J Vet Res 2001;62:1599–1605)

Abstract

Abstract

Objective—To evaluate 2 county trap-neuter-return (TNR) programs for feral cat population management via mathematical modeling.

Design—Theoretical population model.

Animals—Feral cats assessed from 1992 to 2003 in San Diego County, California (n = 14,452), and from 1998 to 2004 in Alachua County, Florida (11,822).

Procedure—Data were analyzed with a mathematical Ricker model to describe population dynamics of the feral cats and modifications to the dynamics that occurred as a result of the TNR programs.

Results—In both counties, results of analyses did not indicate a consistent reduction in per capita growth, the population multiplier, or the proportion of female cats that were pregnant.

Conclusions and Clinical Relevance—Success of feral cat management programs that use TNR can be monitored with an easily collected set of data and statistical analyses facilitated by population modeling techniques. Results may be used to suggest possible future monitoring and modification of TNR programs, which could result in greater success controlling and reducing feral cat populations. ( J Am Vet Med Assoc 2005;227:1775–1781)

Abstract

Objective—To conduct an epidemiological analysis of the spatial and temporal distribution of canine leptospirosis cases in northern California and detect spatial clustering in any region.

Design—Retrospective case-control study.

Animals—67 dogs with leptospirosis and 271 control dogs.

Procedures—Medical records of case and control dogs were reviewed. Spatial coordinates of home addresses of the study population were analyzed visually and statistically via a Cuzick-Edwards test and spatial, temporal, and space-time permutation scan statistics.

Results—Cases were distributed around the San Francisco Bay region as well as in the Sierra Nevada foothills near Sacramento, Calif, whereas controls were principally distributed along route I-80 between San Francisco and Sacramento, Calif. Clustering was found for the second through sixth nearest neighboring cases via the global spatial cluster test. A local spatial cluster of 30 cases was identified in San Francisco (95% confidence interval, 1.3 to 7.0), and a temporal cluster of 18 cases was identified from May 2003 through May 2004 (95% confidence interval, 1.4 to 6.5). No significant space-time cluster was identified.

Conclusions and Clinical Relevance—The use of geographic information systems provided a visual representation of the results of statistical analysis for the location and time at which leptospirosis cases occurred. This useful tool can be used to educate veterinary practitioners and the public about a potentially fatal zoonotic disease and direct vaccination strategies to help prevent disease occurrence.

Abstract

Objective—To determine whether sequelae of infection differed among single versus double infection with Anaplasma phagocytophilum or Anaplasma marginale, with and without tick salivary extract, in cattle.

Animals—Eighteen 13-month old steers.

Procedures—Treatment groups of 3 cattle each included A marginale inoculated ID followed on day 35 by A phagocytophilum without tick saliva, A phagocytophilum followed on day 10 by A marginale without tick saliva, A marginale followed on day 35 by A phagocytophilum with tick saliva, A phagocytophilum followed on day 10 by A marginale with tick saliva, tissue culture control injection, and tick saliva control injection. Infection was monitored via clinical observations, CBC, serologic testing, and PCR analysis of blood and tissues.

Results—Infected cattle had significantly reduced weight gain. Anemia occurred 25 to 32 days after A marginale infection, which was attenuated by tick saliva. Parasitism was greater if cattle had not previously been inoculated with A phagocytophilum. Nine of the 12 treated cattle had positive results of PCR analysis for A phagocytophilum from at least 1 blood sample. Five tissue samples had positive results of PCR analysis for A phagocytophilum; PCR results for A marginale were positive in spleen, lung, lymph node, heart, and ear skin of infected cattle.

Conclusions and Clinical Relevance—Results indicated an important biological interaction between A marginale and A phagocytophilum infection as well as with tick saliva in disease kinetics and severity in cattle, which may be important for interpretation of diagnostic tests and management of disease in areas where both pathogens occur.

Abstract

Objective—To evaluate disease progression in sheep experimentally inoculated with Anaplasma phagocytophilum and determine the Anaplasma spp seroprevalence in sheep in free-ranging flocks in the Sierra Nevada foothills and Oregon Coast Range.

Animals—10 mature ewes seronegative for Anaplasma spp and 251 sheep from 8 flocks.

Procedures—10 ewes received 1 of 3 treatments: A phagocytophilum Webster strain (n = 4), A phagocytophilum MRK strain (4), or human promyelocytic leukemia cells (control treatment [2]). Sheep were monitored for signs of clinical disease, and blood samples were obtained for serologic and PCR assay evaluation intermittently for 48 days. From a subsample of sheep from each of 8 free-ranging flocks, blood samples were obtained to determine Anaplasma spp seroprevalence.

Results—Sheep inoculated with A phagocytophilum developed subclinical or mild disease, whereas sheep inoculated with the control treatment did not develop any signs of disease. Only 2 ewes seroconverted; both had received the MRK strain. Anaplasma-specific DNA was detected in blood samples from 1 sheep in the Webster strain–inoculated group and 3 sheep in the MRK strain–inoculated group. Sheep seropositive for Anaplasma spp were detected in 5 of 8 flocks, and flocks in the Sierra Nevada foothills had higher within-flock seroprevalence (22%) than did flocks in the Oregon Coast Range (6.4%).

Conclusions and Clinical Relevance—Infection with A phagocytophilum in mature sheep generally resulted in subclinical disease. Higher Anaplasma spp seroprevalence in sheep in the Sierra Nevada foothills corresponded to the geographic distribution of anaplasmosis reported for dogs, horses, and humans.

Abstract

Objective–To determine detection rates for feline herpesvirus type 1 (FHV-1), Mycoplasma spp, fungi, and bacteria in flush samples and biopsy specimens from the nasal cavities of cats with and without chronic rhinosinusitis (CRS).

Design–Prospective study.

Animals–10 CRS-affected cats and 7 cats without signs of respiratory tract disease.

Procedures–Nasal flush samples and biopsy specimens were collected from all cats for bacterial (aerobic and anaerobic), fungal, and mycoplasmal cultures; additional biopsy specimens were collected for virus isolation and polymerase chain reaction (PCR) assay (to detect FHV-1 DNA).

Results–Aerobic bacteria were detected in flush samples from 5 of 7 control cats; culture of flush samples from CRS-affected cats yielded aerobic bacteria (9/10 cats), anaerobic bacteria (3/10), and Mycoplasma spp (2/10). No fungal organisms were isolated from any cat. Potential pathogens were isolated significantly more often from CRS-affected cats than from control cats. Bacterial culture of biopsy specimens yielded aerobic bacteria (2/7 control cats and 4/10 CRS-affected cats) and anaerobic bacteria (2/10 CRS-affected cats). Although FHV-1 was not detected in nasal biopsy specimens from control or CRS-affected cats, FHV-1 DNA was detected via PCR assay in specimens from 4 of 7 control cats and 3 of 10 CRS-affected cats.

Conclusions and Clinical Relevance–Compared with findings in control cats, anaerobic bacteria, Mycoplasma spp, and a variety of potentially pathogenic organisms were detected more commonly in samples from cats with CRS. In both groups, FHV-1 was detected via PCR assay as a nonviable organism or in noncultivable amounts. (J Am Vet Med Assoc 2005;227:579–585)

Abstract

Objective—To determine incidence rates (IRs) and potential risk factors for owner-reported adverse events (AEs) following vaccination of dogs that did or did not receive a Leptospira vaccine.

Design—Observational, retrospective cohort study.

Animals—130,557 dogs.

Procedures—Electronic records of mobile veterinary clinics from June 2012 to March 2013 were searched to identify dogs that received ≥ 1 vaccine in a given visit. Signalment data, vaccinations received, medications administered, and owner-reported clinical signs consistent with AEs that developed ≤ 5 days after vaccination were recorded. Associations between potential risk factors and owner-reported AEs were evaluated by logistic regression analysis.

Results—The IR/10,000 dogs for owner-reported postvaccination AEs was 26.3 (95% CI, 23.6 to 29.2), whereas that for dogs that received a Leptospira vaccine alone or with other vaccines was 53.0 (95% CI, 42.8 to 64.9). Significant factors for increasing or decreasing risk of AEs were as follows: receiving a Leptospira vaccine (adjusted OR, 2.13), age at vaccination 1 to < 7 or ≥ 7 years (vs a referent of < 6 months; adjusted OR, 0.54 and 0.44, respectively), and weight 13.6 to < 22.7 kg (30 to < 50 lb) and 22.7 to < 45.5 kg (50 to 100 lb [vs a referent of < 4.5 kg {10 lb}]; adjusted OR, 0.48 and 0.55, respectively). Hypersensitivity reactions were rare (IR, 6.5/10,000 dogs), and IRs for these events did not differ significantly between dogs vaccinated with or without a Leptospira component.

Conclusions and Clinical Relevance—The overall IR for owner-reported postvaccination AEs was low. Results suggested vaccination against Leptospira (an organism that can cause fatal disease) is safe in the majority of cases, slightly increasing the risk of owner-reported AEs but not associated with a significant increase in hypersensitivity reactions, compared with other vaccinations administered.

Abstract

Objective—To determine incidence of and possible risk factors for catheter-associated urinary tract infection (UTI) among dogs hospitalized in an intensive care unit and compare results of bacterial culture of urine samples with results of bacterial culture of catheter tips.

Design—Prospective study.

Animals—39 dogs.

Procedure—A standard protocol for aseptic catheter placement and maintenance was used. Urine samples were obtained daily and submitted for bacterial culture. When possible, the urinary catheter tip was collected aseptically at the time of catheter removal and submitted for bacterial culture. Bacteria that were obtained were identified and tested for antimicrobial susceptibility.

Results—4 of the 39 (10.3%) dogs developed a UTI. The probability of remaining free from UTI after 1 day in the intensive care unit was 94.9%, and the probability of remaining free from UTI after 4 days was 63.3%. Bacteria isolates were generally common urinary tract pathogens and were susceptible to most antimicrobials. Specific risk factors for catheter-associated UTI, beyond a lack of antimicrobial administration, were not identified. Positive predictive value of bacterial culture of urinary catheter tips was only 25%.

Conclusions and Clinical Relevance—Results suggest that placement of an indwelling urinary catheter in dogs is associated with a low risk of catheter-associated UTI during the first 3 days after catheter placement, provided that adequate precautions are taken for aseptic catheter placement and maintenance. Results of bacterial culture of urinary catheter tips should not be used to predict whether dogs developed catheter-associated UTI. (J Am Vet Med Assoc 2004;224:1936–1940)

Abstract

Objective—To characterize isolates of Corynebacterium pseudotuberculosis from horses, cattle, and sheep in Colorado, Kentucky, Utah, and California in samples collected during perceived epidemics of infection (increased numbers of cases identified) in 2002 and 2003, and determine how closely isolates were related and their possible source.

Sample Population—54 isolates of C pseudotuberculosis from 49 horses, 4 cattle, and 1 sheep.

Procedures—Random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) assay, PCR assay for the gene encoding the phospholipase D (PLD) toxin, biochemical analyses, and tests for susceptibility to 17 antimicrobial drugs were performed.

Results—All isolates reduced nitrate to nitrite, most yielded positive results for the PLD toxin gene, and all were susceptible to antimicrobial drugs. Ten genetic types were detected by use of RAPD PCR assay; types III to X were isolated from horses, cattle, or both in 1 or more states. Types III and IX were isolated from both horses and cattle. Types VII and VIII were isolated in only 1 state, but the number of isolates in these groups was small. In contrast, all other types were isolated in 2 or more states. All isolates from Utah were type III, but the other 3 states had isolates from more than 1 type.

Conclusions and Clinical Relevance—These data are consistent with a clonally expanding epidemic of infection in Utah and an increase in number of infections caused by multiple strains of C pseudotuberculosis not derived from a single source in the other states. The increase in number of infections could be the result of reporting bias, environmental factors facilitating infection, or host factors such as greater herd susceptibility. (Am J Vet Res 2004;65:1734–1737)