Temperature and exudativory as drivers of the marmoset (Callithrix spp.) daily activity period

Primates are affected by fluctuations in ambient temperatures, mostly through thermoregulatory costs and changes in the availability of food. In the present study, we investigate whether the ambient temperature and proxies of food availability affect the activity period of marmosets (Callithrix spp.). We predicted that: (i) at colder sites, marmosets would spend more time at sleeping sites; (ii) midday resting bouts would be longer at hotter sites; (iii) the onset/cessation of activity and resting behavior at midday would be more closely related to temperature than food availability, and (iv) highly exudativorous groups would have higher total levels of resting. We compiled data on the onset and cessation of activity and the time spent resting at midday from seven marmoset studies from sites with a wide range of temperatures. We used generalized linear mixed models to verify the relationship between the dependent variables (lag between dawn and the onset of activities, lag between cessation of activities and dusk, and proportion of resting during midday) and the minimum and maximum temperatures at the respective study sites, together with proxies of food availability (exudativory rates, the amount of habitat available per individual, and net primary productivity) using each sample month as a sampling unit and the identity of the study as a categorical random factor. At colder sites and during colder months, the marmosets left sleeping trees later in the morning and ceased their activities earlier, while at hotter sites and during hotter months, they spent more time resting during midday. More exudativorous groups become active later in the morning, but also ceased their activities later. The abundance of food did not affect the timing of activities. We provide evidence that both low and high temperatures affect marmosets' activities, and that their activity period appears to be more influenced by the thermal environment than food availability.

Treatment of primate platynosomosis: A word of caution about the use of praziquantel in marmosets

BACKGROUND

The successive reports of Platynosomum illiciens in Neotropical captive primates have increased interest in platynosomosis; however, its treatment is little known.

METHODS

Callithrix penicillata (n = 10) naturally and chronically infected with P. illiciens were treated with praziquantel (25 mg/kg BW, three s.c. doses at 24 hours intervals), and coproparasitological tests performed over 67 days. The proportions of primates with a reduction in fecal egg counts (FEC) or negative results progressively increased after treatment, and at the last fecal tests, marmosets were negative.

RESULTS AND CONCLUSIONS

Although all primates tolerated the initial days of study well, 40% (4/10) of them died between the 8th and 16th days after the onset of treatment. Clinical signs and necropsies indicated the occurrence of hepatic involvement, biliary obstruction, and cholangitis. Marmosets with a higher previous FEC were more likely to die after treatment. Use of praziquantel should be considered carefully on a case-by-case basis.

Spatial distribution of buffy-tufted-ear (Callithrix aurita) and invasive marmosets (Callithrix spp.) in a tropical rainforest reserve in southeastern Brazil

We investigated the spatial distribution of native and invasive marmoset species (Callithrix), as well as their hybrids, in the Serra dos Órgãos National Park (PARNASO) and surrounding area in Rio de Janeiro state, Brazil. To estimate occupancy and the detection probability, we surveyed 56 sites within the park and 52 sites outside its limits using vocal playbacks, as well as by interviewing local residents in the surrounding area. We estimated the occupancy and detection probability of Callithrix aurita and the observed groups composed of Callithrix jacchus, Callithrix penicillata, and their hybrids. We also recorded the presence or absence of mixed groups of native and exotic species, and their hybrids. We recorded similar occupancy rates and detection probabilities for both native and invasive species within the national park. C. aurita was found more often within the areas of the park located furthest from access roads and with the least human interference, while invasive species were more likely to be found along the edge of the park and in areas with greater human interference. In the area surrounding the park, invasive marmosets were recorded at seven sites, and a mixed group of native and invasive marmosets was observed at one site, but non-hybrid C. aurita groups were not recorded. The occupancy probability of C. aurita in the study area is relatively low, which may indicate a low population density, with groups restricted to a small region within the PARNASO in the proximity of groups of invasive marmosets.

Hierarchical Cluster Analysis of Three-Dimensional Reconstructions of Unbiased Sampled Microglia Shows not Continuous Morphological Changes from Stage 1 to 2 after Multiple Dengue Infections in Callithrix penicillata

It is known that microglial morphology and function are related, but few studies have explored the subtleties of microglial morphological changes in response to specific pathogens. In the present report we quantitated microglia morphological changes in a monkey model of dengue disease with virus CNS invasion. To mimic multiple infections that usually occur in endemic areas, where higher dengue infection incidence and abundant mosquito vectors carrying different serotypes coexist, subjects received once a week subcutaneous injections of DENV3 (genotype III)-infected culture supernatant followed 24 h later by an injection of anti-DENV2 antibody. Control animals received either weekly anti-DENV2 antibodies, or no injections. Brain sections were immunolabeled for DENV3 antigens and IBA-1. Random and systematic microglial samples were taken from the polymorphic layer of dentate gyrus for 3-D reconstructions, where we found intense immunostaining for TNFα and DENV3 virus antigens. We submitted all bi- or multimodal morphological parameters of microglia to hierarchical cluster analysis and found two major morphological phenotypes designated types I and II. Compared to type I (stage 1), type II microglia were more complex; displaying higher number of nodes, processes and trees and larger surface area and volumes (stage 2). Type II microglia were found only in infected monkeys, whereas type I microglia was found in both control and infected subjects. Hierarchical cluster analysis of morphological parameters of 3-D reconstructions of random and systematic selected samples in control and ADE dengue infected monkeys suggests that microglia morphological changes from stage 1 to stage 2 may not be continuous.

FILAMENTOUS FUNGI ISOLATED FROM THE FUR MICROBIOTA OF CALLITRICHIDS KEPT IN CAPTIVITY IN BRAZIL

This study aimed to isolate filamentous fungi from the fur of primates of the genus Callithrix kept in the Centre for Rehabilitation of Wild Animals (CRWA) at the Tietê Ecological Park, São Paulo, SP, Brazil. Samples of the fur of 19 specimens of black-tufted marmosets (Callithrix penicillata) and 6 specimens of white-tufted-ear marmosets (Callithrix jacchus) were obtained by the square carpet technique. The samples were plated on Mycosel™ agar medium (Difco™) and incubated at 25°C for 21 days. The identification of each isolated mold was based on its macroscopic and microscopic features and followed classical recommendations. The following filamentous fungi were isolated: Penicillium spp. (76%), Cladosporium spp. (60%), Acremonium spp. (44%), Scopulariopsis spp. (24%), Aspergillus spp. (16%), Chrysosporium spp. (16%), and Fusarium spp. (8%). Dermatophyte fungi were not detected. We conclude that C. penicillata and C. jacchus kept in captivity are sources of potentially pathogenic filamentous fungi that may represent a risk factor for immunocompromised individuals who may eventually establish contact with them.

Conjunctival flora, Schirmer's tear test, intraocular pressure, and conjunctival cytology in neotropical primates from Salvador, Brazil

BACKGROUND

This study aimed to establish reference values for selected ophthalmic diagnostic tests in healthy neotropical primates from Salvador, Brazil.

METHODS

A total of 73 intact adults, including Callithrix jacchus (n = 31), Callithrix penicillata (n = 8), Cebus sp. (n = 22), and Cebus xanthosternos (n = 9) were used to evaluate the normal conjunctival bacterial flora. Cebus xanthosternos (n = 12) were used to evaluate tear production with Schirmer's tear test (STT), intraocular pressure (IOP), and conjunctival cytology.

RESULTS

For all animals evaluated, Gram-positive bacteria were predominant. Results of the diagnostic tests in Cebus xanthosternos were as follows: STT: 14.92 ± 5.46 mm/minutes, IOP: 19.62 ± 4.57 mmHg, and conjunctival cytology revealed intermediate squamous epithelial cells in great quantities.

CONCLUSIONS

These ophthalmic reference values will be particularly useful to diagnose discrete or unusual pathological changes in the neotropical primates eye.