Objective—To investigate the effects of preexisting
FeLV infection or FeLV and feline immunodeficiency
(FIV) coinfection on the pathogenicity of the small
variant of Haemobartonella felis (Hfsm, California variant)
Animals—20 FeLV infected, 5 FeLV-FIV coinfected,
and 19 retrovirus-free cats.
Procedure—A client-owned cat, coinfected with
FeLV and Hfsm, was the source for Hfsm.
Inoculum 1 (FeLV free) was obtained by passage of
source Hfsm through 4 FeLV-resistant cats.
Inoculum 2 was obtained by further passage of
Hfsm (inoculum 1) through 2 specific pathogenfree
Results—A mild-to-moderate anemia started 21 days
after inoculation, with its nadir occurring at 35 to 42
days after inoculation. Infection with Hfsm induced
greater decrease in hemoglobin concentration in FeLV
infected cats, compared with retrovirus free cats.
Reticulocytosis, macrocytosis, and polychromasia of
erythrocytes developed in anemic cats regardless of
retrovirus infection status. Mean neutrophil counts
decreased during the hemolytic episode. For most
cats, the anemia was transient. Four FeLV infected
cats, 1 of which was also FIV infected, developed fatal
FeLV-associated myeloproliferative diseases. Of the
surviving cats, 8 died over the next 24 months from
other FeLV-related diseases. Hemolysis did not recur
after the initial episode. Inoculum 1 induced more
severe anemia than inoculum 2.
Conclusions and Clinical Relevance—Our results
support the clinical observation that cats coinfected
with FeLV and H felis develop more severe anemia
than cats infected with H felis alone. Infection with
Hfsm may induce myeloproliferative disease in FeLV
infected cats. The small variant of H felis may lose
pathogenicity by passage through FeLV-free cats.
(Am J Vet Res 2002;63:1172–1178)
Objective—To characterize infection patterns and identify factors associated with avian mycobacteriosis among zoo birds that were housed with infected enclosure mates.
Design—Matched case-control study.
Animals—79 birds with avian mycobacteriosis (cases) and 316 nondiseased birds (controls) of similar age and taxonomic group that were present in the bird collection of the Zoological Society of San Diego from 1991 through 2005.
Procedures—Inventory and necropsy records from all eligible, exposed birds (n = 2,413) were examined to determine disease incidence and prevalence in the exposed cohort. Cases were matched in a 1:4 ratio to randomly selected controls of similar age and taxonomic grouping. Risk factors for mycobacteriosis (demographic, temporal, enclosure, and exposure characteristics as well as translocation history) were evaluated with univariate and multivariable conditional logistic regression analyses.
Results—Disease prevalence and incidence were estimated at 3.5% and 8 cases/1,000 bird-years at risk, respectively. In the multivariable model, cases were more likely to have been imported into the collection, exposed to mycobacteriosis at a young age, exposed to the same bird species, and exposed in small enclosures than were controls. Odds for disease increased with an increasing amount of time spent with other disease-positive birds.
Conclusions and Clinical Relevance—The low incidence of mycobacteriosis and the risk factors identified suggested that mycobacteria may not be easily transmitted through direct contact with infected enclosure mates. Identification of risk factors for avian mycobacteriosis will help guide future management of this disease in zoo bird populations.
OBJECTIVE To determine the incidence of and risk factors for clinical feline herpesvirus (FHV) infection in zoo-housed cheetahs and determine whether dam infection was associated with offspring infection.
DESIGN Retrospective cohort study.
ANIMALS 144 cheetah cubs born in 6 zoos from 1988 through 2007.
PROCEDURES Data were extracted from the health records of cheetahs and their dams to identify incident cases of clinical FHV infection and estimate incidence from birth to 18 months of age. Univariate and multivariable Cox proportional hazards models, controlling for correlations among cheetahs with the same dam, were used to identify risk factors for incident FHV infection.
RESULTS Cumulative incidence of FHV infection in cheetah cubs was 35% (50/144). No significant association between dam and offspring infection was identified in any model. Factors identified as significant through multivariable analysis varied by age group. For cheetahs up to 3 months of age, the most important predictor of FHV infection was having a dam that had received a preparturition FHV vaccine regimen that included a modified-live virus vaccine versus a dam that had received no preparturition vaccine. Other risk factors included being from a small litter, being born to a primiparous dam, and male sex.
CONCLUSIONS AND CLINICAL RELEVANCE This study provided the first population-level characterization of the incidence of and risk factors for FHV infection in cheetahs, and findings confirmed the importance of this disease. Recognition that clinical FHV infection in the dam was not a significant predictor of disease in cubs and identification of other significant factors have implications for disease management.