Primate

About: Primate is a research topic. Over the lifetime, 1250 publications have been published within this topic receiving 67388 citations. The topic is also known as: the primate order & primates.

Threat to Humans from Virus Infections of Non-human Primates

Abstract: Several hundred distinct non human primate species are recognised, and they are likely to harbour a similar range of viruses to humans. Simians such as cynomolgus and rhesus macaques, African green monkeys, and marmosets are widely used for biomedical research, but despite this extensive close contact very few simian viruses have been shown to pose a threat of infection or illness to humans. Herpesvirus Simiae is the best recognised zoonotic hazard of simians. It is an alphaherpes virus of Asiatic macaques, which causes a mild or subclinical primary infection followed by latency in its natural host. It can be acquired by humans following a bite and causes an ascending meningoencephalitis. Less than 40 human cases have been described and the mortality rate in untreated human infections is 70%. The infection is treatable with acyclovir and extensive guidelines for managing simians and potential exposures have been developed. Ebola virus and Marburg virus have caused epizootics in cynomolgus macaques and vervet monkeys respectively, which have resulted in human infection and fatalities. However, non human primates are unlikely to be their natural host. More recently simian immunodeficiency virus and simian foamy virus have infected researchers, but infection has not been linked to illness. Simian viruses also pose a direct threat to humans through the use of primary monkey tissue cultures in laboratory work and vaccine manufacture, indeed a significant exposure of the human population occurred when cells contaminated with SV40 a polyomavirus of rhesus monkeys were used for polio vaccine production. New medical interventions such as xenotransplantation using primate organs pose a potential risk which requires careful assessment. Copyright 1997 by John Wiley & Sons Ltd.

Development of l-CDB-4022 as a nonsteroidal male oral contraceptive: induction and recovery from severe oligospermia in the adult male cynomolgus monkey (Macaca fascicularis).

Abstract: The present study was undertaken to examine the antispermatogenic effect of l-CDB-4022 in the adult male cynomolgus monkey. Monkeys (four per group) were dosed via nasogastric tube for 7 d with l-CDB-4022 at 12.5 mg/kg.d or vehicle (d 0=first day of dosing). Plasma levels of l-CDB-4022 and its deesterified metabolite were nondetectable prior to treatment and in all vehicle-treated monkeys. Peak levels of l-CDB-4022 and its metabolite were observed at 4 h after dosing with steady-state levels apparent around d 4. Sperm concentration and total sperm per ejaculate were decreased to levels below 1x10(6) sperm/ml or sperm/ejaculate in l-CDB-4022-treated monkeys by d 17 and remained suppressed through wk 6. Sperm motility also declined to 0% for 6 wk. Testicular volume was reduced in l-CDB-4022-treated monkeys through d 21. The left testis and epididymis were removed from all monkeys on d 24. At this time, the most mature germ cells in the seminiferous tubules of testes from l-CDB-4022-treated monkeys were either spermatocytes or round spermatids. Immature germ cells, but not mature sperm, were found in the efferent ducts and collapsed epididymal lumen of l-CDB-4022-treated monkeys. A steady recovery in sperm motility, concentration, and total sperm per ejaculate was observed in l-CDB-4022-treated monkeys such that these parameters were not different from those of vehicle-treated monkeys by wk 16. Volume of the remaining testis increased in vehicle- and l-CDB-4022-treated monkeys after hemicastration; however, the increase in l-CDB-4022-treated monkeys was delayed compared with that observed in the vehicle-treated monkeys. The morphology of the remaining testis and epididymis, which were removed on wk 17, was normal. Serum inhibin B levels were increased in l-CDB-4022-treated monkeys during the dosing interval; thereafter serum inhibin B levels declined such that there was no difference between the groups by wk 3. l-CDB-4022 treatment did not affect circulating levels of testosterone, LH, FSH, or estradiol. In conclusion, these data indicate that in the cynomolgus monkey, a representative higher primate, l-CDB-4022 exerts a selective antispermatogenic action, which was reversible under the conditions of this study and thus has potential as a nonhormonal oral male contraceptive.

Blood-sucking Flies And Primate Polyspecific Associations

Abstract: PRIMATE polyspecific associations are likely to be an effective means of reducing the number of fly bites individual monkeys receive1. The probability of acquiring a vector-borne disease, and the severity of that disease increases with the number of fly bites an animal receives2–4. Bait animals placed in groups are known to attract fewer individual mosquitoes per bait individual than are bait animals placed singly3,5. Mean group size of the mangabey, Cercocebus albigena is about 13 in Kibale Forest, Uganda, and the mean group size of Colobus badius and Cercopithecus ascanius are 50 and 35 respectively6. Associations of groups of these species are likely to reduce significantly the number of dipteran bites individual monkeys receive1,7. Other explanations proposed for primate polyspecific associations include increased food location abilities, and increased predator detection and avoidance8,9. I report here the correlation of the temporal occurrence of C. albigena polyspecific associations with the activity of biting and sucking flies, C. albigena feeding and other activities, and the temporal occurrence of attacks by the crowned eagle-hawk (Stephanoaetus coronatus) (eagles are the only known predator of these monkeys). The study was carried out in the Kibale Forest, Ngogo Reserve.

Diet and feeding behaviour of samango monkeys (Cercopithecus mitis labiatus) in Ngoye Forest, South Africa.

Abstract: The samango monkey occurs at the southern limit of the range of Cercopithecus mitis. Greater climatic seasonality at this latitude results in more predictable fruiting patterns. In addition, there are no diurnal sympatric primate frugivores. Under these conditions, the diet and feeding strategies of samango monkeys would be expected to differ notably from those of central or east African C. mitis subspecies. Contrary to these expectations, the preliminary observations reported here indicate that diets of samango and blue monkeys differ only superficially in the proportions of items eaten. Similarities in feeding behaviour are especially marked during the dry season period when fruit is not abundant. Both samango and blue monkeys tend to be less selective in their choice of food species and to eat available food species regardless of their energy content; a shift toward less nutritious items such as leaves is also noted. Feeding behaviour during the summer wet season is characterized by the selection of fruits with high-energy values. A high proportion of visits by the monkeys to areas of greater food availability suggests a concentration of feeding effort in food patches and the selection of higher energy food species within patches.

The retinal ganglion cell classes of New World primates.

Abstract: In the primate retina there are distinct ganglion cell classes, exhibiting particular morphologies and central projections, each responsible for conveying particular types of visual information to the brain. The chief retinal inputs to the cortex arise from specific ganglion cell classes, M-ganglion cells, responsible for carrying the luminance signal, and P-ganglion cells, that convey the red-green color opponent signal, as well as high contrast luminance signal. There are other ganglion cell classes, such as small-field bistratified cells, exhibiting dendrites that stratify at two different levels in the inner plexiform layer, which convey the blue-yellow color opponent signal. Most published data concerning primate retinal ganglion cell anatomy and physiology have been obtained from Old World species. Studies on New World monkeys have recently become of interest since they differ from the Old World monkeys with respect to the color vision inheritance pattern. On reviewing retinal ganglion cell layer organization in New World monkeys, it seems that there are more similarities than differences in relation to the Old World monkeys. Diurnal genera of New World monkeys exhibit a well-developed fovea centralis and ganglion cell density peak, as well as peripheral density values which are in the range reported for Old World monkeys and human. Moreover, all the major ganglion cell classes identified in Old World monkeys are also present in New World primates. Up to now, no obvious anatomical differences between dichromats and trichromats have been reported. The only genus that is significantly different from the others is the Aotus. It exhibits lower ganglion cell density in the central retina, and apparently lacks the small-field bistratified cells.