Primate

Similarities between humans, apes and monkeys are an obvious advantage to medical researchers. Primates share more biological and behavioral characteristics with humans than any other animal species. From monkeys and apes, we have gained insights into human language and behavior, Parkinson's and Alzheimer's diseases, respiratory distress syndrome, intrauterine surgery, nutrition and more.

The conquest of polio began in 1909, when it was demonstrated that poliomyelitis could be transferred from humans to primates. Using monkeys as test models in 1953, Jonas Salk developed the killed polio vaccine used in many countries today. In 1959, the live, modified vaccine currently used in Canada was developed.

Primates became major subjects of cardiac research in the late 1960's, following studies which indicated that the plaque which builds up in the arteries of monkeys is virtually identical to human arterial plaque.

Primates are now used in cardiovascular research to study atherosclerosis and hypertension, as well as the role of diet and exercise on the heart. Research with monkeys exercised on a treadmill, for example, indicates that exercise may help reduce cardiovascular disease and slow the accumulation of arterial plaque.

Primates are also proving to be important models for research on aging. They experience many of the changes in behavior and physiology which humans undergo in the aging process. This makes them ideal candidates for studies such as the effect of diet on  aging, the ability of drugs to reduce memory loss associated with age, and many others.

Research on primate reproductive behavior has been extensive. Basic research carried out in primates has led to the development of fertility control methods. In vitro fertilization techniques have been studied in primates, and these techniques now help not only humans to conceive, but are also helping endangered species to reproduce. The identification of the Rh (rhesus) factor was an early breakthrough in the area of the immunology of pregnancy and resulted from tests on primates, particularly the rhesus monkey.

Physicians who specialize in newborn care and research have applied findings from research with primates to the development of new life-support techniques to sustain newborn infants through critical periods.

Primate research has identified one of the important features of Alzheimer's disease: the abundance of neuritic plaques in the brain of Alzheimer's victims.

Studies of yellow fever in monkeys have led to the testing and production of the first yellow fever vaccine, which was developed from research on the mouse.

Behavioral Studies on Primates Help Mentally-Impaired Children: In the realm of human behavior, humans and apes alone seem capable of linguistic communication. Psychologists have been studying primates since the 1920's in order to understand their communicative abilities. Among the most exciting findings of these studies is the ability of chimpanzees and other apes to learn and use language. Because primates do not have the anatomy required for human speech, ape communication studies use artificial language, such as American Sign Language, plastic symbols, or geometric symbols on a computer-operated keyboard. These studies have demonstrated that apes can develop large vocabularies and improvise their use of language. In one study, two chimpanzees use symbols not only to communicate with each other but also to refer to objects, people and events not immediately present. This research on apes' communicative abilities has provided a practical benefit to human society. For example, a new approach has been developed for teaching language to children who, because of severe mental retardation and other neurological disorders, cannot learn language as normal children do. The computer operated keyboard system of symbols that was developed with apes has been used in the teaching of language to developmentally-challenged children, enabling them to interact with others and better express their thoughts, feelings and needs.

The Nobel Prize-winning research of David Hubel on vision, mentioned earlier in the discussion of cats in medical research, also relied heavily on monkeys. The results of this work emphasized the necessity of early diagnosis and treatment of infants with eye disorders due to the danger of serious and permanent visual impairment.

Primates and other animals are being used in research to study AIDS. Simian (or primate) AIDS virus, closely related to human HIV, was originally isolated from captive rhesus monkeys. Experimental vaccines against simian AIDS have recently shown promise and intense research in this area is underway.

Dental research has also heavily relied on primates for knowledge because they have the same number and relative size of teeth as humans. Macaque monkeys, for example, allowed dental researchers to first link a specific bacterium to the growth of periodontitis. This gum disease, affects 75% of all adults and causes 70% of all adult tooth loss.

Primates continue to be essential to medical research. Whether it be in the study of cancer, dental research, or the search for a malaria treatment or a vaccine for AIDS, monkeys and apes will make major contributions to the elimination of human and animal disease.