Infection and re-infection of domestic cats with various Bartonella species or types: B. henselae type I is protective against heterologous challenge with B. henselae type II.

Four Bartonella species have been isolated from domestic cats, of which two serotypes/genotypes of Bartonella henselae and possibly B. clarridgeiae are human pathogens, causing cat scratch disease (CSD).Our objectives were to evaluate infection and potential cross-protection during re-infection in domestic cats with various Bartonella species or types.Thirty-six cats were primarily inoculated with B. henselae type I (n=16), B. henselae type II (n=10), B. clarridgeiae (n=6) or B. koehlerae (n=4). They were challenged with B. henselae type I (n=15), B. henselae type II (n=13) or B. clarridgeiae (n=8). All 36 cats became bacteremic (1.25x10(2)-1.44x10(6)CFU/ml) and bacteremia lasted from 37 to 582 days. Duration of bacteremia for cats inoculated with B. henselae type I was shorter than for cats inoculated with either B. henselae type II (P=0.025) or B. clarridgeiae (P=0.011). After challenge, 26 cats became bacteremic. Among the nine cats primarily inoculated with B. henselae type I and challenged with B. henselae type II, six cats stayed abacteremic. The three bacteremic cats had a transient low-level bacteremia. No bacteremia was observed in three cats primarily inoculated with B. henselae type I and challenged with another strain of B. henselae type I. Bacteremia levels in the 26 cats were significantly lower than for primary inoculation (P=0.022) and its duration was shorter (P=0.012). Among the eight cats challenged with B. clarridgeiae, duration of bacteremia in the four cats primarily inoculated with B. henselae type I was shorter than in the four cats primarily inoculated with B. henselae type II (P=0.01). Bartonella clarridgeiae inoculated cats were more likely to have relapses for both primary and secondary infections. This is the first demonstration of cross-protection, evidenced by absence of bacteremia, in cats primarily infected with B. henselae type I and challenged with B. henselae type II, whereas no cross-protection was previously shown for cats primarily infected with B. henselae type II and challenged with B. henselae type I. Such results are of major importance for future feline Bartonella vaccine development.

Experimental infection of specific pathogen free (SPF) cats with two different strains of bartonella henselae type I: a comparative study.

Domestic cats are the reservoir of Bartonella henselae, the main causative agent of cat scratch disease. We compared B. henselae type I infection characteristics in 6 SPF cats infected with a feline strain (4.8 x 10(7) colony-forming units (CFU)/mL) and in 6 SPF cats infected with the reference Houston I strain (6.6 x 10(6) CFU/mL to 9.6 x 10(7) /mL). All the cats inoculated with the feline strain, but none of the cats inoculated with B. henselae Houston I, developed a fever within 2-12 days (mean: 5.8 days) post inoculation (PI), which lasted for 1-2 weeks. However, all 12 cats became bacteremic. The duration of bacteremia was significantly longer in the cats inoculated with the feline strain (mean: 237 days) than in the cats inoculated with Houston I strain (mean: 60 days) (p < 0.01). Five (83%) cats inoculated with the feline strain and none of the six cats inoculated with B. henselae Houston I had relapsing bacteremia (p = 0.02). IgG antibodies were detected by IFA within 1-2 weeks for both strains, but peaked later (week 10 versus week 3 PI) for the feline strain. By ELISA, using antigens of each B. henselae strain, all 12 cats developed Bartonella specific IgM and IgG antibodies, but the cats infected with B. henselae Houston I antigen yielded significantly lower optical density values (p < 0.05). By SDS-PAGE, PFGE and Western blotting, protein profile differences (84 to 89% homology) were observed between the two strains. If a feline vaccine is to be developed in order to prevent human infection, the choice of the vaccine strain will be critical, since major differences were identified even between strains belonging to the same sero/genotype.

Hematology and serum biochemistry values of dusky-footed wood rat (Neotoma fuscipes).

Serum chemistry values and complete blood counts were determined for 36 wild dusky-footed wood rats (Neotoma fuscipes) from Sonoma and western Yolo County, California (USA) in summer 1999 and spring 2001. All wood rats had adequate body condition and were hydrated. Many hematologic and biochemical values were comparable to those for house rat (Rattus rattus). There were differences between wood rats tested immediately after capture (those from Yolo County) and after a week of habituation in the laboratory (Sonoma County). Significant differences were noted in red blood cell counts, hemoglobin, hematocrit, neutrophil:lymphocyte ratio, glucose, alanine transaminase, aspartate aminotransferase, and alkaline phosphatase values. The neutrophil:lymphocyte ratio may have been iatrogenically modified in the wood rats tested immediately after capture by stress-induced neutrophilia and lymphopenia. Eosinophilia may have been associated with parasites such as botflies in four individuals, and hyperglycemia in three individuals could have been associated with stress. The cause of elevated enzymes in the animals tested after laboratory habituation is unclear. The hematologic and biochemical values of these apparently healthy wood rats provide valuable baseline information for use in further medical studies performed with this species.

Aeromedical waiver status in U.S. Naval aviators involved in Class A mishaps.

PURPOSE: U.S. Naval aviators are subject to stringent aeromedical standards. Aeromedic waivers are considered when a naval aviator develops a medical condition that is deemed safe for flight, allowing that aviator to continue in a flying status. No Class A (serious) mishap to date has been directly attributable to an aviator's waivered condition. However, to date no study has been conducted to review the overall mishap rate among aviators who are flying with a waiver. This study evaluated the aeromedical waiver status of naval aviators involved in Class A mishaps from 1992-1999. METHOD: Aviation mishaps in the U.S. Navy are investigated by trained personnel, who report their detailed findings to the U.S. Naval Safety Center (NSC). The Navy Operational Medicine Institute (NOMI) maintains a database of all aviation physicals, including the waiver status of individual aviators. A collaborative NSC/NOMI study was done to investigate the prevalence of waivers in mishap and non-mishap aviators. Records were retrieved on 234 naval aviators who were the "pilot at the controls" of Class A mishaps occurring from 1992-1999. This mishap waiver rate was compared with the baseline waiver rate for all pilots in 1994 (midpoint). Odds Ratios were calculated of having a Class A mishap if the aviator had a waiver. RESULTS AND CONCLUSIONS: Analysis failed to find a statistical difference in waiver rates between mishap aviators and the general naval aviator population indicating that the U.S. Naval Aeromedical Service is providing aeromedically safe naval aviators to the fleet.

Experimental infection of domestic cats with Bartonella koehlerae and comparison of protein and DNA profiles with those of other Bartonella species infecting felines.

Bartonella koehlerae, a recently described feline Bartonella species, was isolated from two naturally infected cats in northern California. We experimentally infected domestic cats with B. koehlerae to establish the microbiological and immunological characteristics of this infection in cats and to compare it to infections with those caused by B. henselae and B. clarridgeiae. Four cats were inoculated intradermally with B. koehlerae (8.6 x 10(7) to 3.84 x 10(8) CFU/ml). None of the cats presented any obvious clinical signs, but all cats developed bacteremia, which peaked at 3.36 x 10(4) to 1.44 x 10(6) CFU/ml of blood between day 14 and day 36 postinoculation. B. koehlerae-inoculated cats had a bacteremia duration (mean, 74 days) shorter than did cats inoculated with B. clarridgeiae (mean, 324 days) (P = 0.03). None of the four cats inoculated with B. koehlerae had bacteremia relapse. As shown by enzyme-linked immunosorbent assay (ELISA) using B. koehlerae outer membrane protein (OMP) antigens, the four cats developed a species-specific antibody response, and ELISA testing using other feline Bartonella OMP antigens showed statistically lower optical density values. All four cats developed similar antibody reactivity patterns to B. koehlerae OMP antigens as seen by Western blotting, each with at least 20 seroreactive protein bands. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, protein profile differences were observed for both whole-cell lysate and OMPs from B. koehlerae, compared with B. henselae and B. clarridgeiae. B. koehlerae was more closely related to B. henselae than to B. clarridgeiae by protein profile, and this relatedness was also confirmed by analysis of the genomic DNA profiles by pulsed-field gel electrophoresis.