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Abstract

Objective

To characterize 2 strains of Haemobartonella felis by use of molecular techniques.

Animals

35 specific-pathogen-free cats, 6 months to 4 years old.

Procedure

Intraperitoneal or IV inoculation with blood containing H felis small form (Hfsm, 18 cats) or H felis large form (Hflg, 11 cats); 6 cats were uninfected controls. Hfsm was evaluated for capability to cross-protect against the more virulent Hflg. Morphology of both strains was compared by light microscopy of Wright-Giemsa-stained blood smears, and the 16S rRNA genes were sequenced.

Results

Infection with Hflg induced signs of depression, fever, and severe macrocytic normochromic anemia with nucleated erythrocytes. More than 95% of erythrocytes were parasitized. Inoculation with Hfsm and uninfected control blood induced mild or no clinical signs and no hematologic abnormalities. Anti-Hfelis lgG was first detected on postinoculation day (PID) 21, and increased to maximal titer of 400 by PID 28. Reactivated infection was observed in 8 of 29 cats (4 Hfsm and 4 Hflg), with 5% parasitized erythrocytes during the later attack. On PID 8, Hflg-inoculated cats had positive results of polymerase chain reaction analysis (PCR) that persisted until cats were treated with doxycycline or oxytetracycline; Hfsm-inoculated cats had positive PCR results that persisted for duration of observation (3 months).

Conclusions

Genetically and morphologically distinct strains of H felis infect cats in the field. The level of genetic difference suggested that these strains may be different species or genera.

Clinical Relevance

PCR is a critical diagnostic aid to detect occult Haemobartonella spp infection, as well as response to treatment and clearance of the organism. (Am J Vet Res 1998;59:1581-1588)

Free access
in American Journal of Veterinary Research

antimicrobials were initiated. A 14-French-Foley urinary catheter was placed at the level of the neck of the bladder and the cuff was filled with 5 mL of sterile saline. The urinary catheter was left in place to allow closure of the urachal tear and resolution of

Free access
in Journal of the American Veterinary Medical Association

.r-project.org/ . g. Madigan J, Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, Calif: Personal communication, 2011. References 1. Foley J Biberstein E . Anaplasmataceae . In: Hirsh DC

Full access
in American Journal of Veterinary Research

– 79 . 8. Madigan J . Equine ehrlichiosis . Vet Clin North Am Equine Pract 1993 ; 9 : 423 – 428 . 10.1016/S0749-0739(17)30408-X 9. Foley JE Foley P Madigan JE . Spatial distribution of seropositivity to the causative agent of

Full access
in American Journal of Veterinary Research

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)

Full access
in American Journal of Veterinary Research

-0854 33146112 12. Foley J , Tinoco-Gracia L , Rodriguez-Lomelí M , et al. Unbiased assessment of abundance of Rhipicephalus sanguineus sensu lato ticks, canine exposure to spotted fever group rickettsia, and risk factors in Mexicali, México. Am

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in Journal of the American Veterinary Medical Association

.r-project.org. Accessed Oct 15, 2008. References 1. Foley JE Spier SJ Mihalyi J , et al . Molecular epidemiologic features of Corynebacterium pseudotuberculosis isolated from horses . Am J Vet Res 2004 ; 65 : 1734 – 1737 . 10.2460/ajvr.2004

Full access
in American Journal of Veterinary Research

. 2011 ; 48 ( 2 ): 418 - 421 . doi: 10.1603/me10181 6. Backus LH , López Pérez AM , Foley JE . Effect of temperature on host preference in two lineages of the brown dog tick, Rhipicephalus sanguineus . Am J Trop Med Hyg . 2021 ; 104 ( 6

Full access
in Journal of the American Veterinary Medical Association