Skip to main page content
U.S. flag

An official website of the United States government

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Aug;75(8):872-82.
doi: 10.1002/ajp.22150. Epub 2013 Apr 8.

Risk factor analysis may provide clues to diarrhea prevention in outdoor-housed rhesus macaques (Macaca mulatta)

Affiliations

Risk factor analysis may provide clues to diarrhea prevention in outdoor-housed rhesus macaques (Macaca mulatta)

Kamm Prongay et al. Am J Primatol. 2013 Aug.

Abstract

Seventy-five percent of rhesus macaques at national primate research centers are housed outside. Annually, 15-39% of these animals experience diarrhea and require veterinary treatment for dehydration, electrolyte imbalance, or weight loss. An estimated 21-33% of these patients will die or be euthanized. Many studies have explored the various infectious etiologies of non-human primate diarrhea. However, there is little published information on diarrhea incidence rates and risk factors in outdoor-housed rhesus macaques. Without this information, it is challenging to determine endemic and epidemic diarrhea levels, or to develop and evaluate mitigation strategies. Using electronic medical records, we conducted a retrospective cohort study to calculate diarrhea incidence rates for rhesus macaques (N = 3,181) housed in three different outdoor housing types (corrals, shelters, and temporary housing) at the Oregon National Primate Research Center between November 1, 2009 and October 31, 2010. With multiple logistic regression analysis, we determined the relative risk of housing type, sex, and age on development of diarrhea. Diarrhea incidence and mortality in our population was lower than many published ranges. Type of outdoor housing, age, and previous diarrhea episode were positively correlated with diarrhea risk. Younger animals in smaller shelters and temporary housing had a greater risk of acquiring diarrhea, with juvenile animals (0.7-3.9 years) having the highest mortality rate. Sex was not a risk factor, but adult females with diarrhea were more likely to develop life-threatening complications than adult males. We also constructed a predictive model for diarrhea-associated mortality using Classification and Regression Tree. Findings from this study will be used to develop and evaluate mitigation strategies in our outdoor-housed population and to provide a foundation for genetic susceptibility and immune function testing.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
One acre corral housing for corral-breeding groups (CBGs) of 125–250 animals.
Fig. 2
Fig. 2
Three-bay sheltered housing for shelter-breeding groups (SBGs) of 22–54 animals.
Fig. 3
Fig. 3
Temporary housing run used for temporary groups (STG) of 18–24 animals.
Fig. 4
Fig. 4
Diarrhea-associated mortality and diarrhea incidence shown for each combination of housing, sex, and age. Groups are sorted by sex (male and female), housing type (CBG, Corral-Breeding Group, SBG, Shelter-Breeding Group, and STG, Shelter Temporary Group), and age (infants were <0.7 years, juveniles were >0.7 to <4 years, and adults were ≥4 years). There is a linear relationship between diarrhea incidence and diarrhea-associated mortality for most combinations of age, sex, and housing type (Pearson correlation: r = 0.67, N = 25, P < 0.05). Juvenile females in STG, and both infants and female juveniles in SBG have higher mortality rates. Adult males and females in STG, juvenile males in STG and CBG, and adult males in SBG have lower mortality rates.
Fig. 5
Fig. 5
Diarrhea-associated mortality calculated by month and either housing type (CBG, Corral-Breeding Group, SBG, Shelter-Breeding Group, and STG, Shelter Temporary Group), sex (male, female, and all), or age (infants were <0.7 years, juveniles were >0.7 to <4 years, and adults were ≥4 years) demonstrated a seasonal variance. Overall, January had the highest diarrhea-associated mortality rate and November had the lowest. Most infant-associated mortality occurred during late spring and summer. Juvenile rates were highest in winter.
Fig. 6
Fig. 6
Classification and Regression Tree (CART) developed from the model building set (70% of the data, N = 2,228), using the predictor variable diarrhea-associated mortality. The algorithm searched the response variables housing type, age, and sex to find a split that was most predictive, and generated a binary partition at each such point. Node 1 included all 2,228 cases, classified (Class) by alive (N = 2,155) and dead (N = 73). The first partition resulted in a terminal node for animals in corral housing (CBG, corral-breeding group) and shows 1,023 (98.1%) of these animals are alive and 20 (1.9%) are dead. Further partition of this node did not yield statistically relevant data, so the algorithm stopped. Node 2 included all animals in sheltered housing (SBG, shelter-breeding group) and temporary housing (STG, shelter temporary group). This group was large enough for additional partition. The algorithm identified age as the next predictive response variable, and partitioned this dataset by age (adult at Node 3 and infants and juveniles at Node 4). The algorithm generated a similar partition for the response variable sex, partitioning Node 3 into terminal Node 2 for male and terminal Node 3 for female. The complete model building set achieved overall sensitivity of 71.23% (52 out of 73) and a specificity of 52.85% (1,139 out of 2,155).

Similar articles

Cited by

References

    1. Blanchard JL, Baskin GB, Watson EA. Generalized amyloidosis in rhesus monkeys. Vet Pathol. 1986;23:425–430. - PubMed
    1. Breiman L, Friedman JH, Olshen R, Stone C. Classification and Regression Trees. Belmont (CA): Wadsworth; 1984. p. 368.
    1. Desrosiers RC. The value of specific pathogen-free rhesus monkey breeding colonies for AIDS research. AIDS Res Hum Retroviruses. 1997;13:5–6. - PubMed
    1. Elfenbein HA, McCowan B. The epidemiology of non-pathogenic diarrhea in captive rhesus macaques. J Am Assoc Lab Anim Sci. 2012;52:100.
    1. Elmore DB, Anderson JH, Hird DW, Sanders KD, Lerche NW. Diarrhea rates and risk factors for developing chronic diarrhea in infant and juvenile rhesus monkeys. Lab Anim Sci. 1992;42:356–359. - PubMed

Publication types

LinkOut - more resources