First report of spontaneous hepatic fibrosarcoma in a white-tufted marmoset (Callithrix jacchus) kept in captivity

Reports of sarcomas in nonhuman primates are scarce and, specifically, primary hepatic sarcomas are rare, as in humans. This is the first report of an aggressive hepatic fibrosarcoma in a young adult Callithrix jacchus. The final postmortem diagnosis was obtained by means of immunohistochemical analysis, which confirmed the tumor histogenesis.

Testing the weekend effect hypothesis: Time of day and lunar phase better predict the timing of births in laboratory-housed primates than day of week

The weekend effect hypothesis proposes that captive primates are more likely to give birth during times of low disturbance and reduced staff activity. The hypothesis specifically predicts that laboratory-housed primates will be more likely to give birth during the weekend than weekdays when staff activity is reduced. To date, support for the weekend effect hypothesis has been mixed and based on studies with relatively few subjects. To further examine the hypothesis, we analyzed the birthing patterns of three genera of laboratory-housed primates: squirrel monkeys (Saimiri species, N = 2,090 births), owl monkeys (Aotus species, N = 479 births), and rhesus macaques (Macaca mulatta, N = 2,047 births). Contrary to predictions derived from the weekend effect hypothesis, the frequencies of births during weekends for all taxa were not significantly different from rates that would be expected by chance. However, while there was no variance across days of the week, all three taxa gave birth at nighttime, when staff was absent. This parallels reports of births in wild and captive monkeys, both diurnal and nocturnal, which are more likely to give birth during the night; plausibly a time when the environmental and social disturbance is lowest and the mother is safest to bond with her newborn infant. As all births occurred at night, we also explored the relationship between the lunar cycle and the timing of births timing. While the diurnal primates (i.e., Saimiri and Macaca) were no more likely to give birth on "bright" nights than "dark" nights, owl monkeys (Aotus) had a much higher frequency of births on bright nights than darker ones, and at rates that deviated from chance. Our data provide a more detailed understanding on how the environment may influence captive monkey births but do not support the oft-cited weekend effect hypothesis.

Architectonic characteristics of the visual thalamus and superior colliculus in titi monkeys

Titi monkeys are arboreal, diurnal New World monkeys whose ancestors were the first surviving branch of the New World radiation. In the current study, we use cytoarchitectonic and immunohistochemical characteristics to compare titi monkey subcortical structures associated with visual processing with those of other well-studied primates. Our goal was to appreciate features that are similar across all New World monkeys, and primates in general, versus those features that are unique to titi monkeys and other primate taxa. We examined tissue stained for Nissl substance, cytochrome oxidase (CO), acetylcholinesterase (AChE), calbindin (Cb), parvalbumin (Pv), and vesicular glutamate transporter 2 (VGLUT2) to characterize the superior colliculus, lateral geniculate nucleus, and visual pulvinar. This is the first study to characterize VGLUT2 in multiple subcortical structures of any New World monkey. Our results from tissue processed for VGLUT2, in combination with other histological stains, revealed distinct features of subcortical structures that are similar to other primates, but also some features that are slightly modified compared to other New World monkeys and other primates. These included subdivisions of the inferior pulvinar, sublamina within the stratum griseum superficiale (SGS) of the superior colliculus, and specific koniocellular layers within the lateral geniculate nucleus. Compared to other New World primates, many features of the subcortical structures that we examined in titi monkeys were most similar to those in owl monkeys and marmosets, with the lateral geniculate nucleus consisting of two main parvocellular layers and two magnocellular layers separated by interlaminar zones or koniocellular layers.

25-OH-vitamin D, parathyroid hormone, and calcium serum levels in captive common marmosets (Callithrix jacchus): Reference values and effect of age, sex, season, and closure of long bone epiphyses

BACKGROUND

To date, reference values for 25-OH-vitamin D, parathyroid hormone (PTH), and calcium in serum of common marmosets (Callithrix jacchus) based on a large sample size are not available.

METHODS

Serum reference values for these parameters were determined and correlated with sex, age, season of sampling, and time of long bone epiphyseal closure in captive-housed marmosets.

RESULTS AND CONCLUSIONS

The 90% reference range for serum 25-OH-vitamin D is 47.40-370.4 nmol/L, for PTH 2.10-30.51 pmol/L, and for calcium 2.08-2.63 mmol/L. Lower levels of vitamin D were measured in fall compared with the other seasons. Levels of PTH were higher in males than in females, and calcium levels were lower in younger animals compared with older marmosets. No other effects of age, sex, season, or timing of growth plate closure were found.

Detection of Mycobacterium tuberculosis Complex in New World Monkeys in Peru

The Mycobacterium tuberculosis complex causes tuberculosis in humans and nonhuman primates and is a global public health concern. Standard diagnostics rely upon host immune responses to detect infection in nonhuman primates and lack sensitivity and specificity across the spectrum of mycobacterial infection in these species. We have previously shown that the Oral Swab PCR (OSP) assay, a direct pathogen detection method, can identify the presence of M. tuberculosis complex in laboratory and free-ranging Old World monkeys. Addressing the current limitations in tuberculosis diagnostics in primates, including sample acquisition and pathogen detection, this paper furthers our understanding of the presence of the tuberculosis-causing bacteria among New World monkeys in close contact with humans. Here we use the minimally invasive OSP assay, which includes buccal swab collection followed by amplification of the IS6110 repetitive nucleic acid sequence specific to M. tuberculosis complex subspecies, to detect the bacteria in the mouths of Peruvian New World monkeys. A total of 220 buccal swabs from 16 species were obtained and positive amplification of the IS6110 sequence was observed in 30 (13.6%) of the samples. To our knowledge, this is the first documentation of M. tuberculosis complex DNA in a diverse sample of Peruvian Neotropical primates.