Socialization strategies and disease transmission in captive colonies of nonhuman primates

Abstract

In captive research environments for nonhuman primates (NHP), social housing strategies are often in conflict with protocols designed to minimize disease transmission. This is particularly true in breeding colonies, and is especially relevant when attempting to eliminate specific pathogens from a population of primates. Numerous strategies have been used to establish such specific pathogen free (SPF) breeding colonies (primarily of macaques), ranging from nursery rearing of neonates to single housing of socially-reared yearlings to the rearing of infants in large social groups. All of these strategies attempt to balance the effects of the chosen socialization strategy on parameters related to disease transmission, including the ultimate elimination of the target pathogens. Such strategies may affect the overall disease states of NHP breeding colonies through selective breeding processes. This can occur either by creating subpopulations of animals that do not have target diseases (SPF colonies), but may have other issues; or by creating situations in which the ‘best’ animals are sold and the breeding colony is stocked with animals that may be more disease susceptible than those that were sold. The disease states of NHP research colonies also may be affected by selective utilization programs, in which animals removed from the breeding colony for health/behavior reasons, are preferentially chosen for use in scientific investigations. Such utilization criteria raise the question of whether ideal subjects are being chosen for use in research. Finally, captive primate colonies, where both socialization and disease states are intensely managed, may provide opportunities for those testing predictions from models of the interactions of socialization and disease transmission in the evolution of wild populations of NHP. This would be especially true for some extreme conditions of these disease ecology models, given the exceedingly high social densities and levels of pathogen control that exist in many captive nonhuman primate colonies.

Feasibility of successfully breeding rhesus macaques (Macaca mulatta) to obtain healthy infants year‐round

“…In contrast, the primarily older, multiparous females in the timed mating program mostly had healthy pregnancies that successfully reached term with unassisted deliveries. Across both breeding strategies, the overall live birth rate of 94% is comparable with other research colonies that have live birth rates of 95% when monkeys are in large social groups (Schapiro & Bernacky, 2012) and 92% in animals bred with a similar timed-mating protocol (Wolf et al, 2004).…”

Effect of living conditions on biochemical and hematological parameters of the cynomolgus monkey

“…in socially housed subjects. The social environment creates monkey‐monkey disease transmission opportunities that single housing prevents [Schapiro & Bernacky, ]. Moreover, social housing contains many animal enrichment products, such as toys, which can serve as potential fomites; microbial growth has been shown to persist on these devices [Bayne et al, ].…”

Social Processes and Disease in Nonhuman Primates: Introduction to the Special Section

“…may not be selected out of the population, such as might occur in the wild. Schapiro & Bernacky [2012] remind us that primates in captivity still exist within an ecological setting and within a selection environment that has implications for disease processes.…”

“…Schapiro’s more than two decades of experience at this colony encompasses the period during which there has been a desire to derive SPF colonies of rhesus macaques. Schapiro & Bernacky [2012] are explicit that captive management of nonhuman primate colonies typically involves goals that are somewhat in opposition to each other: to minimize disease transmission and to maximize social opportunities. Moreover, they acknowledge that the determining factor in a captive management plan is more likely to be prevention of disease transmission, inasmuch as there are fewer options to successfully achieve this goal than there are options available for meeting the social needs of the animals.…”

“…They describe the SPF derivation strategy that was employed at their institution, which was an attempt to balance these two needs, as well as the procedures used to minimize pathogen transmission—use of personal protective equipment, and standardizing human “traffic” patterns within the colony, for example. Finally, Schapiro & Bernacky [2012] present the interesting idea that captive colonies may be useful for testing some ideas about disease ecology. For example, population densities are extremely high (for rhesus monkeys, they report densities of 9.3 animals/km 2 in the wild versus approximately 17,241 animals/km 2 in their colony), and the goal of maintaining pathogen prevalence at zero is never actually achieved.…”