Epidemiology of clinical feline herpesvirus infection in zoo-housed cheetahs (Acinonyx jubatus)

Abstract

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.

Figure 1—

Age distribution of incident cases of clinical FHV infection from birth to 18 months in 50 young cheetahs (Acinonyx jubatus) housed at 6 zoos.

Figure 2—

Kaplan-Meier curves showing the probability of young zoo-housed cheetahs (n = 144) developing a clinical FHV infection as a function of age from birth to 3 months (A) and > 3 to 18 months (B), stratified by whether the dam did (red line) or did not (blue line) have a clinical history of FHV infection at any time in the past. Dashed lines represent 95% CIs.

Figure 3—

Kaplan-Meier curves showing the probability of young zoo-housed cheetahs developing a clinical FHV infection as a function of age, stratified by whether the dam received a preparturition vaccine regimen that included an MLV FHV vaccine (red line), only a KV booster vaccine while pregnant (green line), or no preparturition vaccine (blue line). The MLV vaccine regimen included a KV vaccine, followed 3 weeks later with an MLV vaccine prior to breeding, followed by a KV booster while pregnant.