A survey of the pathology of marmosets (Callithrix jacchus) derived from a marmoset breeding unit

Effects of enhanced insect feeding on the faecal microbiota and transcriptome of a family of captive common marmosets (Callithrix jacchus)

Common marmosets have been widely used in biomedical research for years. Nutritional control is an important factor in managing their health, and insect intake would be beneficial for that purpose because common marmosets frequently feed on insects in natural habitats. Here, we examined the effect of enhanced insect feeding on the gut by analysing the faecal microbiota and transcripts of captive marmosets. A family consisting of six marmosets was divided into two groups. During the seven-day intervention period, one group (the insect feeding group, or Group IF) was fed one cricket and one giant mealworm per marmoset per day, while the other (the control group, or Group C) was not fed these insects. RNA was extracted from faecal samples to evaluate the ecology and transcripts of the microbiota, which were then compared among time points before (Pre), immediately after (Post), and two weeks after the intervention (Follow_up) using total RNA sequencing. The gut microbiota of marmosets showed Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria as dominant phyla. Linear discriminant analysis showed differential characteristics of microbiota with and without insect feeding treatment. Further analysis of differentially expressed genes revealed increases and decreases in Bacteroidetes and Firmicutes, respectively, corresponding to the availability of insects under both Post and Follow_up conditions. Significant changes specific to insect feeding were also detected within the transcriptome, some of which were synchronized with the fluctuations in the microbiota, suggesting a functional correlation or interaction between the two. The rapid changes in the microbiota and transcripts may be achieved by the microbiota community originally developed in the wild through marmosets' feeding ecology. The results were informative for identifying the physiological impact of insect feeding to produce a better food regimen and for detecting transcripts that are currently unidentifiable.

The Common Marmoset-Biomedical Research Animal Model Applications and Common Spontaneous Diseases

Marmosets are becoming more utilized in biomedical research due to multiple advantages including (1) a nonhuman primate of a smaller size with less cost for housing, (2) physiologic similarities to humans, (3) translatable hepatic metabolism, (4) higher numbers of litters per year, (5) genome is sequenced, molecular reagents are available, (6) immunologically similar to humans, (7) transgenic marmosets with germline transmission have been produced, and (8) are naturally occurring hematopoietic chimeras. With more use of marmosets, disease surveillance over a wide range of ages of marmosets has been performed. This has led to a better understanding of the disease management of spontaneous diseases that can occur in colonies. Knowledge of clinical signs and histologic lesions can assist in maximizing the colony's health, allowing for improved outcomes in translational studies within biomedical research. Here, we describe some basic husbandry, biology, common spontaneous diseases, and animal model applications for the common marmoset in biomedical research.

Aromatase Inhibition Eliminates Sexual Receptivity Without Enhancing Weight Gain in Ovariectomized Marmoset Monkeys

Context

Ovarian estradiol supports female sexual behavior and metabolic function. While ovariectomy (OVX) in rodents abolishes sexual behavior and enables obesity, OVX in nonhuman primates decreases, but does not abolish, sexual behavior, and inconsistently alters weight gain.

Objective

We hypothesize that extra-ovarian estradiol provides key support for both functions, and to test this idea, we employed aromatase inhibition to eliminate extra-ovarian estradiol biosynthesis and diet-induced obesity to enhance weight gain.

Methods

Thirteen adult female marmosets were OVX and received (1) estradiol-containing capsules and daily oral treatments of vehicle (E2; n = 5); empty capsules and daily oral treatments of either (2) vehicle (VEH, 1 mL/kg, n = 4), or (3) letrozole (LET, 1 mg/kg, n = 4).

Results

After 7 months, we observed robust sexual receptivity in E2, intermediate frequencies in VEH, and virtually none in LET females (P = .04). By contrast, few rejections of male mounts were observed in E2, intermediate frequencies in VEH, and high frequencies in LET females (P = .04). Receptive head turns were consistently observed in E2, but not in VEH and LET females. LET females, alone, exhibited robust aggressive rejection of males. VEH and LET females demonstrated increased % body weight gain (P = .01). Relative estradiol levels in peripheral serum were E2 >>> VEH > LET, while those in hypothalamus ranked E2 = VEH > LET, confirming inhibition of local hypothalamic estradiol synthesis by letrozole.

Conclusion

Our findings provide the first evidence for extra-ovarian estradiol contributing to female sexual behavior in a nonhuman primate, and prompt speculation that extra-ovarian estradiol, and in particular neuroestrogens, may similarly regulate sexual motivation in other primates, including humans.

Naturally Occurring Endocrine Disorders in Non-Human Primates: A Comprehensive Review

Literature concerning veterinary medicine of non-human primates is continuously updated, yet endocrine disorders remain underreported. While case or survey reports of individual endocrinopathies are available, a comprehensive review is not. An exhaustive literature search on this subject via widely used academic search systems, (e.g., Google Scholar, PubMed, BioOne complete and Web of Science), and peer-reviewed publications, proceedings, and newsletters was performed. Selected major endocrine entities will be described with emphasis on clinical signs, morphologic appearances, concomitant diseases, as well as available treatment options. Mostly, no clinical signs were noted and on gross pathology, the endocrine organs were unremarkable. An endocrine-related diagnosis was frequently made as an incidental finding after standard histopathological examination. During the review, the pancreas represented the most affected endocrine organ and diabetes mellitus represented the most clinically significant disorder. Currently, no standard procedure for diagnosing, monitoring, or treating endocrine disorders in non-human primates exists.

Immunohistochemical Characterization of a Duodenal Adenocarcinoma with Pulmonary, Hepatic and Parapatellar Metastases in a Common Marmoset (Callithrixjacchus)

An 11-year-old male common marmoset (Callithrix jacchus) presented with chronic, progressive weight loss and diarrhoea. Response to treatment with nutritional supplementation, antibiotics and immunosuppressants was modest and transient, and the animal was humanely euthanized. At necropsy, the proximal 8 cm of small intestine was diffusely pale with transmural thickening. The lungs contained coalescing tan, firm nodules measuring up to 4 mm in diameter. Histological examination revealed infiltrative mucinous adenocarcinoma of the duodenum with extensive metastases to the lungs, liver and left parapatellar adipose tissue. The mucinous matrix secreted by the primary and metastatic lesions was strongly periodic acid-Schiff positive. Warthin Starry staining for spirochaetes was negative. Pancytokeratin expression was attenuated in the primary tumour as well as in the metastases, which correlated to a poorly differentiated phenotype. To the authors' knowledge, this is the first report of a proximal duodenal adenocarcinoma with extensive metastatic disease in a common marmoset.

Research Relevant Conditions and Pathology in Nonhuman Primates

Biomedical research involving animal models continues to provide important insights into disease pathogenesis and treatment of diseases that impact human health. In particular, nonhuman primates (NHPs) have been used extensively in translational research due to their phylogenetic proximity to humans and similarities to disease pathogenesis and treatment responses as assessed in clinical trials. Microscopic changes in tissues remain a significant endpoint in studies involving these models. Spontaneous, expected (ie, incidental or background) histopathologic changes are commonly encountered and influenced by species, genetic variations, age, and geographical origin of animals, including exposure to infectious or parasitic agents. Often, the background findings confound study-related changes, because numbers of NHPs used in research are limited by animal welfare and other considerations. Moreover, background findings in NHPs can be exacerbated by experimental conditions such as treatment with xenobiotics (eg, infectious morphological changes related to immunosuppressive therapy). This review and summary of research-relevant conditions and pathology in rhesus and cynomolgus macaques, baboons, African green monkeys, common marmosets, tamarins, and squirrel and owl monkeys aims to improve the interpretation and validity of NHP studies.

Spontaneous (Hashimoto-like) chronic lymphocytic thyroiditis in a rhesus macaque (Macaca mulatta)

A case of a female, 10-year-old rhesus macaque (Macaca mulatta) with spontaneous chronic lymphocytic thyroiditis is presented. At necropsy, the thyroid gland was slightly enlarged, with up to 2 mm large, round, confluent, beige foci on the surface of both lobes. Histopathologic features resembled human Hashimoto's thyroiditis: multifocally, the interstitium was infiltrated by lymphocytes and variably sized lymphoid follicles. In the pituitary gland, there were increased numbers of large, basophilic cells throughout the adenohypophysis. Using a human electrochemiluminescence immunoassay (ECLIA), no autoantibodies against thyroglobulin, thyroid peroxidase, or thyroid-stimulating hormone receptor were detected.

Marmosets: Welfare, Ethical Use, and IACUC/Regulatory Considerations

Use of marmosets in biomedical research has increased dramatically in recent years due, in large part, to their suitability for transgenic applications and utility as models for neuroscience investigations. This increased use includes the establishment of new colonies and involvement of people new to marmoset research. To facilitate the use of the marmoset as a research model, we provide an overview of issues surrounding the ethics and regulations associated with captive marmoset research, including discussion of the history of marmosets in research, current uses of marmosets, ethical considerations related to marmoset use, issues related to importation of animals, and recommendations for regulatory oversight of gene-edited marmosets. To understand the main concerns that oversight bodies have regarding captive biomedical research with marmosets, we developed a brief, 15-question survey that was then sent electronically to academic and biomedical research institutions worldwide that were believed to house colonies of marmosets intended for biomedical research. The survey included general questions regarding the individual respondent's colony, status of research use of the colony and institutional oversight of both the colony itself and the research use of the colony. We received completed surveys from a total of 18 institutions from North America, Europe, and Asia. Overall, there appeared to be no clear difference in regulatory oversight body concerns between countries/regions. One difference that we were able to appreciate was that while biomedical research with marmosets was noted to be either stable or decreasing in Europe, use was clearly increasing elsewhere.

Clinical Management of Gastrointestinal Disease in the Common Marmoset (Callithrix jacchus)

Gastrointestinal disease is a frequently encountered problem among captive common marmoset (Callithrix jacchus) colonies. Management can be challenging due to the number of etiologies responsible for gastrointestinal disease in this species, limitations on diagnostic capabilities, and lack of effective treatments. Understanding commonly described GI diseases in the captive marmoset can provide insight on the impact these diseases have on research studies and aid in the development of appropriate management strategies. A review of commonly encountered GI disease processes as well as routinely implicated causes of GI disease in the common marmoset are provided. Current strategies in clinical management of GI disease in the common marmoset, including approaches to colony health, diagnostic testing, and commonly employed treatments are discussed.

Discovery of a Novel Simian Pegivirus in Common Marmosets (Callithrix jacchus) with Lymphocytic Enterocolitis

From 2010 to 2015, 73 common marmosets (Callithrix jacchus) housed at the Wisconsin National Primate Research Center (WNPRC) were diagnosed postmortem with lymphocytic enterocolitis. We used unbiased deep-sequencing to screen the blood of deceased enterocolitis-positive marmosets for viruses. In five out of eight common marmosets with lymphocytic enterocolitis, we discovered a novel pegivirus not present in ten matched, clinically normal controls. The novel virus, which we named Southwest bike trail virus (SOBV), is most closely related (68% nucleotide identity) to a strain of simian pegivirus A isolated from a three-striped night monkey (Aotus trivirgatus). We screened 146 living WNPRC common marmosets for SOBV, finding an overall prevalence of 34% (50/146). Over four years, 85 of these 146 animals died or were euthanized. Histological examination revealed 27 SOBV-positive marmosets from this cohort had lymphocytic enterocolitis, compared to 42 SOBV-negative marmosets, indicating no association between SOBV and disease in this cohort (p = 0.0798). We also detected SOBV in two of 33 (6%) clinically normal marmosets screened during transfer from the New England Primate Research Center, suggesting SOBV could be exerting confounding influences on comparisons of common marmoset studies from multiple colonies.

Presence of the annular ridge and location of the coronary sinus ostium as morphological features ofthe right atrium and interatrial septum in healthy common marmosets (Callithrix jacchus)

To effectively use a common marmoset (Callithrix jacchus) as an experimental animal species, it is critical to establish a normal characteristics and morphology of the organs of the common marmoset. Although gross morphology of the common marmoset heart is reportedly the same as that of humans, little information is available regarding detailed morphology of the right atrium and the interatrial septum. Heart specimens were collected from three male and 10 female marmosets aged 9 to 65 months to determine the morphological features of the right atrium and the interatrial septum. Ten specimens were evaluated morphologically with a stereoscopic microscope in accordance with preparation and investigation methods designed to facilitate evaluation. Three specimens were histologically evaluated after being stained with hematoxylin-eosin, Elastica van Gieson and periodic acid Schiff. An annular ridge that is not present in the human heart was present in the right atrium and the interatrial septum of the common marmoset hearts. Tissue structure of the annular ridge was similar to atrial myocardial fibers. Furthermore, location of the coronary sinus ostium was different to that in humans. Present findings were used to create a schematic view of the annular ridge in the common marmoset heart. In the common marmoset heart, the annular ridge may function as a valve of the superior vena cava ostium, inferior vena cava ostium, and coronary sinus ostium. Present study provides morphological evidence that common marmosets have a valve-like structure in the right atrium.

Successful management of Heinz body hemolytic anemia associated with leek (Allium ampeloprasum) ingestion in a South American coati (Nasua nasua)

OBJECTIVE

To describe the diagnosis, management, and outcome of Heinz body hemolytic anemia in a South American coati (Nasua nasua) secondary to suspected leek (Allium ampeloprasum) toxicosis.

CASE SUMMARY

A South American coati presented with Heinz body hemolytic anemia following addition of leeks to its diet for 2-5 days prior to initial presentation. Administration of a whole blood transfusion from an animal of the same species (conspecific) and supportive care resulted in immediate improvement in clinical signs. Normal behavior fully returned within 6 days of transfusion. Hematological evidence of anemia resolved by 4 weeks and there were no significant features of oxidative injury present by 8 weeks following initial presentation.

NEW INFORMATION PROVIDED

This is the first reported case of Heinz body hemolytic anemia, suspected leek toxicosis, and administration of a blood transfusion in this species.

Radiographic evaluation of the forelimbs and hind limbs of marmosets (Callithrix spp.)

BACKGROUND

The maintenance of marmosets in captivity may trigger various disorders. The objective of this study was to provide a radiographic evaluation of the forelimbs and hind limbs of marmosets rescued from illegal wildlife trade and maintained in captivity.

METHODS

Fourteen marmosets were studied.

RESULTS AND CONCLUSIONS

Three marmosets were apparently normal. Of the eleven marmosets with radiographic changes in the hind limbs, five had pelvic narrowing and bilateral varus deviation of the femur, with one suggestive of rickets and another of osteomalacia. The other marmosets showed changes such as malunion of acetabular fracture, transtibial amputation, tibial antecurvatum, and knee osteoarthritis. Six marmosets showed alterations in the forelimbs such as radius fracture, scapulohumeral subluxation, and elbow joint incongruence. In conclusion, 78.57% of the marmosets had bone and/or joint changes detected by plain radiography, which were found predominantly in the hind limbs and without impediment to locomotion in captivity.

Diet, digestion and energy intake in captive common marmosets (Callithrix jacchus): research and management implications

Common marmosets (Callithrix jacchus) are susceptible to intestinal inflammation which leads to chronic diarrhea, weight loss, and vitamin D deficiency. We examined food intake and digestion in three mixed-sex groups of adult marmosets maintained on three commercial base diets. Animals underwent two consecutive 4-day digestion trials. Body mass stayed constant. Feces and diet were assayed for Mn, fat, and gross energy (GE). Apparent digestibility of dry matter (ADDM) was calculated by the total collection method and from dietary and fecal Mn; the methods produced correlated results (r = 0.658, p < 0.001). Apparent digestibility of energy (ADE) was calculated from ADDM and the GE of feces and diet; apparent digestibility of fat (ADfat) was calculated from ADDM and fecal fat. ADDM and ADE varied by diet (p < 0.001). We found poor digesters on all three diets. The concentration of fecal fat was inversely related to ADE (r = -0.729, p < 0.001). High fecal fat (>10%) was associated with ADfat of zero, consistent with lipid malabsorption. Mean digestible energy intake (DEI) was equal to 1.5 the estimated metabolic rate, but varied widely between individuals. The diet with the fewest animals with high fecal fat had the highest mean DEI and most animals above 450 g, suggesting it may be obesogenic.

RETROSPECTIVE MORTALITY REVIEW OF SIX CALLITRICHID SPECIES HOUSED AT A SINGLE INSTITUTION (1990-2014)

Callitrichids are commonly exhibited species in zoological institutions. Retrospective mortality studies allow institutions to evaluate health trends in captive populations and have the potential to advance zoological medicine and husbandry practices. In this single institution, retrospective study, histopathologic records were reviewed for 166 callitrichids comprising six species. For all species and age-groups combined, trauma was the leading cause of death followed by enteritis and stillbirth. In adults and juveniles, the leading cause of death was enteritis, with neonates dying primarily from trauma. Neonatal mortality was high for most species, ranging from 12.5% to 60%, with most neonatal loss in Geoffroy's and pied tamarins. Twin births were commonly associated with neonatal mortality in most species. Intestinal adenocarcinoma was a common finding for adult Geoffroy's tamarin, and hemosiderosis was also identified in this species. Renal disease was a common finding in adult callitrichids and was the second most common cause of death in this age-group. Mortality in the juvenile period (>30 days-1 yr) was uncommon, comprising only 8.4% of the data set. Although capable of surviving into advanced age (>20 yr for one animal), the average age at death for all age classes was 3.84 yr and 9.31 yr for adults. This study contributes to the current knowledge regarding trends in callitrichid health and husbandry and can be used to investigate health trends in this group.

Serum Cobalamin and Folate Concentrations in Common Marmosets (Callithrix jacchus) with Chronic Lymphocytic Enteritis

Serum cobalamin and folate concentrations can serve as surrogate markers of gastrointestinal disease in dogs and cats, where they can have diagnostic, therapeutic, and prognostic implications. Chronic disease of the gastrointestinal tract, particularly chronic lymphocytic enteritis (CLE), occurs frequently in captive common marmosets. The aims of this study were to validate a commercially available assay for measuring serum cobalamin and folate concentrations in common marmosets, to establish reference intervals for these analytes in healthy marmosets, and to measure serum concentrations in common marmosets with CLE. The commercial assay was linear, accurate, precise, and reproducible for the measurement of serum cobalamin and folate concentrations in common marmosets. In healthy marmosets, the serum cobalamin concentration ranged from 322 to 2642 pg/mL (n = 35) and serum folate concentration from 54.8 to 786.4 ng/mL (n = 37). Low serum folate concentrations were moderately sensitive (greater than 70%) for CLE, and low serum cobalamin concentrations were moderately (greater than 70%) specific for CLE. Both serum cobalamin and folate concentrations were relatively unchanged in marmosets during 120 to 220 d. Serum cobalamin and folate concentrations were stable for approximately 7 y when samples were stored at -80 °C. Additional studies are warranted to further study the clinical implications of low serum cobalamin and folate concentrations in common marmosets.

Fecal Concentrations of N-methylhistamine in Common Marmosets (Callithrix jacchus)

Chronic lymphocytic enteritis (CLE) is a frequent disease in common marmosets. However, no diagnostic test for early detection of CLE is available. Mast cells have an important role in gastrointestinal disease. The purpose of this study was to measure fecal concentrations of N-methylhistamine (NMH), a breakdown product of histamine metabolism, in common marmosets. A previously established NMH gas chromatography-mass spectrometry assay for canine feces and urine was used, and partial validation was performed. The reference intervals (n = 30) established for fecal NMH concentrations in common marmoset were 118.2 ng/g or less for a single fecal sample, 121.7 ng/g or less for the 3-d mean, and less than or equal to 167.5 ng/g for the 3-d maximum. Considerable day-to-day variation was observed in fecal NMH concentrations; the mean %CV was 42.2% (minimum, 7.1%; maximum, 141.4%). Fecal NMH concentrations were measured in 14 marmosets for which necropsy reports were available; 7 of the 8 marmosets with CLE and the 1 animal with lymphoma and ulcerative enteritis had increased fecal NMH concentrations. Increased fecal NMH concentrations may serve as a potential marker for CLE; however, further studies exploring the role of mast cells in marmosets with CLE are needed.

Cross-sectional comparison of health-span phenotypes in young versus geriatric marmosets

The development of the marmoset as a translational model for healthspan and lifespan studies relies on the characterization of health parameters in young and geriatric marmosets. This cross-sectional study examined health phenotypes in marmosets for five domains of interest for human health and aging: mobility, cognition, metabolism, homeostasis, and immune function. Geriatric marmosets were found to have significant executive function impairment when compared to young animals. While geriatric animals did not show gross abnormalities in mobility and measures of locomotion, their types of movement were altered from young animals. Geriatric marmosets had alterations in cardiac function, with significantly increased mean arterial pressures; metabolism, with significantly lower VO2 ; and suppressed immune function. Further, this study sought to characterize and describe histopathology for both young and geriatric healthy marmosets. Overall this study provides a characterization of health parameters for young and geriatric marmosets which will greatly enhance future aging and interventional testing in marmosets.

Parasitic Diseases

Captive marmosets, whether in zoos or biomedical research facilities, may become infected or infested with a variety of internal or external parasites. Modern animal housing and husbandry practices have greatly reduced the prevalence of parasitism, particularly for those parasites requiring an intermediate host. In this chapter, the author discusses selected parasitic diseases of captive marmosets. This chapter is organized phylogenetically. No attempt is made to cover all of the internal and external parasites historically reported, no matter how infrequently. Similarly, no attempt is made to cover parasites infecting or infesting other New World primates and thus potentially found in or on marmosets. The author has included those parasitisms most likely to be observed in modern animal facilities.

Spontaneous lung pathology in a captive common marmoset colony (Callithrix jacchus)

Data on spontaneous pathology are substantially scarce for common marmosets, compared to other laboratory animals, but is essential for the interpretation of histological findings in the context of toxicological and experimental studies. Especially if common marmosets are used as experimental animals in respiratory research, detailed knowledge on the spectrum, occurrence, and incidence of spontaneous histopathological pulmonary lesions in this non-human primate species is required. In this study, lung tissue of 638 common marmosets from the marmoset colony of the German Primate Center was examined histologically. The analysis revealed a high incidence of predominantly mild and multifocal interstitial pneumonia (32.99 %) of unknown etiology in most cases. Only few marmosets exhibited lobar pneumonia (1.41 %) and bronchopneumonia (0.94), which were mainly caused by bacterial pathogens such as Bordetella bronchiseptica and Klebsiella pneumoniae. Lung immaturity and atelectasis were common histological findings in newborn marmosets. Typical background lesions included anthracosis (8.15 %), hemosiderosis (1.72 %), extramedullary hematopoiesis (11.6 %), mineralization (10.97 %), and inflammatory cell foci (10.34 %). In addition, three cases of pulmonary arteriopathy (0.47 %) and 1 case of foreign-body granuloma (0.16 %) were detected in the marmoset study cohort. The high prevalence of circulatory disturbances (congestion, edema, hemorrhage) and changes in air content (secondary atelectasis, alveolar emphysema) could partly be explained by euthanasia-related artifacts or agonal changes. The present study provides a comprehensive overview of the range and incidence of spontaneous pulmonary histopathology in common marmosets, serving as valuable reference data for the interpretation of lung lesions in toxicological and experimental marmoset studies.

Metabolic Characterization of the Common Marmoset (Callithrix jacchus)

High-resolution metabolomics has created opportunity to integrate nutrition and metabolism into genetic studies to improve understanding of the diverse radiation of primate species. At present, however, there is very little information to help guide experimental design for study of wild populations. In a previous non-targeted metabolomics study of common marmosets (Callithrix jacchus), Rhesus macaques, humans, and four non-primate mammalian species, we found that essential amino acids (AA) and other central metabolites had interspecies variation similar to intraspecies variation while non-essential AA, environmental chemicals and catabolic waste products had greater interspecies variation. The present study was designed to test whether 55 plasma metabolites, including both nutritionally essential and non-essential metabolites and catabolic products, differ in concentration in common marmosets and humans. Significant differences were present for more than half of the metabolites analyzed and included AA, vitamins and central lipid metabolites, as well as for catabolic products of AA, nucleotides, energy metabolism and heme. Three environmental chemicals were present at low nanomolar concentrations but did not differ between species. Sex and age differences in marmosets were present for AA and nucleotide metabolism and warrant additional study. Overall, the results suggest that quantitative, targeted metabolomics can provide a useful complement to non-targeted metabolomics for studies of diet and environment interactions in primate evolution.

Validation of qPCR Methods for the Detection of Mycobacterium in New World Animal Reservoirs

Zoonotic pathogens that cause leprosy (Mycobacterium leprae) and tuberculosis (Mycobacterium tuberculosis complex, MTBC) continue to impact modern human populations. Therefore, methods able to survey mycobacterial infection in potential animal hosts are necessary for proper evaluation of human exposure threats. Here we tested for mycobacterial-specific single- and multi-copy loci using qPCR. In a trial study in which armadillos were artificially infected with M. leprae, these techniques were specific and sensitive to pathogen detection, while more traditional ELISAs were only specific. These assays were then employed in a case study to detect M. leprae as well as MTBC in wild marmosets. All marmosets were negative for M. leprae DNA, but 14 were positive for the mycobacterial rpoB gene assay. Targeted capture and sequencing of rpoB and other MTBC genes validated the presence of mycobacterial DNA in these samples and revealed that qPCR is useful for identifying mycobacterial-infected animal hosts.

Isolation and characterization of a novel Helicobacter species, Helicobacter jaachi sp. nov., from common marmosets (Callithrix jaachus)

Purpose-bred common marmosets from domestic sources housed in a US research facility, and used in multiple drug discovery programmes, were noted to have a high incidence of spontaneous inflammatory bowel disease and sporadic cholecystitis and cholangiohepatitis. Inflammatory infiltrates increased in incidence and severity with age. Because Helicobacter spp. have been linked to gastrointestinal diseases, samples from the gastrointestinal tracts of 39 marmosets were screened for Helicobacter spp. by culture and PCR. Helicobacter spp. were frequently detected in marmosets; 28.2% of the marmosets were positive for a proposed novel species, Helicobacter jaachi sp. nov., by culture, and 48.7% were positive by Helicobacter genus-specific PCR. Seventeen strains of Helicobacter sp. from 11 marmosets were cultured from various gastrointestinal sites. Older animals (age 6-11 years) had a higher helicobacter prevalence rate (57.1%) compared with younger animals (age 3-5 years), which had a 27.2% prevalence rate. Cells of H. jaachi sp. nov. were catalase, urease and oxidase positive and had fusiform morphology, with periplasmic fibres and multiple bipolar, sheathed flagella. All isolates had similar 16S and 23S rRNA sequences, which clustered as representatives of a novel Helicobacter species closely related to 'Helicobacter sanguini' (97%), a species isolated from cotton-top tamarins and 'Helicobacter callitrichis' (96%) isolated previously from the faeces of common marmosets. The whole genome sequence of one of the liver isolates, H. jaachi sp. nov. MIT 09-6949(T), had a 1.9 Mb genome length with a 41 mol% DNA G+C content. The type strain of Helicobacter jaachi sp. nov., MIT 09-6949(T), has been deposited in the BCCM/LMG Bacteria Collection as LMG 28613(T). These findings add to the increasing number of animal species with gastrointestinal disease in which novel enterohepatic Helicobacter spp. have been isolated.

Bone Disease in the Common Marmoset: Radiographic and Histological Findings

The common marmoset (Callithrix jacchus) is a New World primate that is used in biomedical research due to its small size and relative ease of handling compared with larger primates. Although bone disease in common marmosets is well recognized, there are very few detailed descriptions in the literature that cover the range of lesions seen in these animals. For all animals used to model human disease, it is important to be aware of background lesions that may affect the interpretation of study findings. This retrospective study details bone diseases encountered in marmoset breeding colonies at 2 different institutions. Affected marmosets at Johns Hopkins University had lesions compatible with diagnoses of rickets, fibrous osteodystrophy and osteopenia. Affected marmosets at the Wisconsin National Primate Research Center exhibited severe lesions of osteoclastic bone resorption and remodeling that had an unusual distribution and were not easily categorized into a known disease entity. The purpose of this report is to document these naturally occurring skeletal lesions of common marmosets and suggest an approach to evaluating skeletal disease in prospective studies of these animals that will allow the most accurate diagnoses.

Nasal, oral and rectal microbiota of Black lion tamarins (Leontopithecus chrysopygus)

Black lion tamarins (Leontopithecus chrysopygus) are endangered callithrichids. Their conservation may require future translocations or reintroductions; however these approaches involve risks of pathogen introduction in the environment and stress-related opportunistic infections in these animals. In order to screen for opportunistic and potential pathogenic bacterial and fungal microbiota, ten free-ranging and ten captive Black lion tamarins were studied and the results compared. Nasal, oral and rectal swabs were collected and cultured for aerobic and facultative anaerobic bacteria and fungi, and a total 203 bacterial and 84 fungal isolates were obtained. Overall, the most frequent organisms were Staphylococcus spp., Bacillus spp., Candida spp. and Aspergillus spp. Microbiota of free-ranging and captive animals were similar in composition. A number of potentially pathogenic organisms were identified, emphasizing the importance of microbiological screening in future translocation or reintroduction conservation management programs.

Purification and partial characterization of α1-proteinase inhibitor in the common marmoset (Callithrix jacchus)

Fecal alpha1-proteinase inhibitor (α1-PI) concentration has been to diagnose enteric protein loss in dogs and cats. Chronic lymphocytic enteritis is commonly seen in the marmoset (Callithrix jaccus) and is characterized by hypoalbuminemia. As a prelude to immunoassay development for detecting enteric protein loss, marmoset serum α1-PI was purified using immunoaffinity chromatography and ceramic hydroxyapatite chromatography. Partial characterization was performed by reducing gel electrophoresis and enzyme inhibitory assays. Protein identity was confirmed with peptide mass fingerprinting and N-terminal amino acid sequencing. Molecular mass, relative molecular mass, and isoelectric point for marmoset α1-PI were 54 kDa, 51,677, and 4.8-5.4, respectively. Trypsin, chymotrypsin, and elastase inhibitory activity were observed. N-terminal amino acid sequence for marmoset α1-PI was EDPQGDAAQKMDTSHH. In conclusion, marmoset α1-PI was successfully purified from serum with an overall yield of 12% using a rapid and efficient method. Purified marmoset α1-PI has characteristics similar to those of α1-PI reported for other species.

Five-sixth Nephrectomy in Female Common Marmosets(Callithrix jacchus) as a Chronic Renal Failure Model: -A Longitudinal Course of Serum Biochemical, Hematological and Histopathological Changes-

To assess the relevance and availability of subtotal nephrectomized common marmoset monkeys as a chronic renal failure (CRF) model, we observed for 26 weeks the pathophysiological condition of female marmosets subjected to five-sixth surgical nephrectomy (5/6Nx) by a two-step surgical method. The 5/6Nx marmosets showed a significant increase in serum levels of urea nitrogen, creatinine and cystatin-C immediately after 5/6Nx surgery. These renal disorder parameters subsequently tended to decrease with the passage of time but remained higher than the control levels by the end of the study. Hyperplastic parathyroid glands, a high turnover state of osteodystrophy in the femoral bone with higher serum ALP activity and anemia with hypocellularity of bone marrow were evident. The 5/6Nx marmosets showed a stable CRF condition for a long time and some characteristic disorders similar to those observed in CRF patients. These diagnostic aspects might be a species-specific anatomical and physiological signature, reflecting the nutritional condition. The CRF model using 5/6Nx marmosets might become a useful method of evaluating the unique mechanism of CRF development.

Serum albumin and body weight as biomarkers for the antemortem identification of bone and gastrointestinal disease in the common marmoset

The increasing use of the common marmoset (Callithrix jacchus) in research makes it important to diagnose spontaneous disease that may confound experimental studies. Bone disease and gastrointestinal disease are two major causes of morbidity and mortality in captive marmosets, but currently no effective antemortem tests are available to identify affected animals prior to the terminal stage of disease. In this study we propose that bone disease and gastrointestinal disease are associated disease entities in marmosets and aim to establish the efficacy of several economical antemortem tests in identifying and predicting disease. Tissues from marmosets were examined to define affected animals and unaffected controls. Complete blood count, serum chemistry values, body weight, quantitative radiographs, and tissue-specific biochemical markers were evaluated as candidate biomarkers for disease. Bone and gastrointestinal disease were associated, with marmosets being over seven times more likely to have either concurrent bone and gastrointestinal disease or neither disease as opposed to lesions in only one organ system. When used in tandem, serum albumin <3.5 g/dL and body weight <325 g identified 100% of the marmosets affected with concurrent bone and gastrointestinal disease. Progressive body weight loss of 0.05% of peak body weight per day predicted which marmosets would develop disease prior to the terminal stage. Bone tissue-specific tests, such as quantitative analysis of radiographs and serum parathyroid hormone levels, were effective for distinguishing between marmosets with bone disease and those without. These results provide an avenue for making informed decisions regarding the removal of affected marmosets from studies in a timely manner, preserving the integrity of research results.

Valores eletrocardiográficos em saguis-de-tufo-preto (Callithrix penicillata)

O conhecimento de parâmetros cardíacos em animais modelo experimentais é essencial para a investigação médica comparativa. Nosso estudo teve como objetivo estabelecer parâmetros eletrocardiográficos e valores de referência para saguis-de-tufo-preto (Callithrix penicillata). Dezenove saguis-de-tufo-preto adultos saudáveis foram utilizados. Uma combinação de tiletamina e zolazepam foi empregada para contenção química antes da realização do exame eletrocardiográfico (ECG). Foi utilizado para o exame de ECG um equipamento computadorizado. Os valores dos parâmetros do ECG encontrados foram frequência cardíaca média de 264±74 bpm, uma variação do eixo cardíaco médio entre 60° e -90°, a duração da onda P média de 34±6ms e amplitude de 0,132±0,051mV, um intervalo PR com duração de 56±11ms, duração média do complexo QRS de 35±7ms e amplitude de 0,273±0,269mV, duração do intervalo QT de 130±26ms, segmento ST isoelétrico (13 animais) e com supradesnível (seis animais) e uma amplitude de onda T de 0,19±0,083mV e com polaridade positiva. Não houve diferença significativa entre machos e fêmeas. Os parâmetros eletrocardiográficos obtidos em nosso estudo em saguis-de-tufo-preto podem ser utilizados como referência em outras pesquisas futuras, oferecendo aos pesquisadores parâmetros eletrocardiográficos que contribuem com a literatura.

Improving the energy and nutrient supply for common marmoset monkeys fed under long-term laboratory conditions

BACKGROUND

Current knowledge about the optimal energy and nutrient supply for common marmoset monkeys (Callithrix jacchus) is scarce, and more information is needed for establishing the underlying nutritional concepts for facilitating longevity of this species as laboratory animals for biomedical research.

METHODS

Two feeding experiments were conducted to yield fundamental data about feed acceptance, real feed intake, and feed preferences under laboratory conditions. Newly developed feeding concepts for marmoset monkeys were also examined in preliminary investigations to compare the outcomes with those of a commercial pelletized mixed feed.

RESULTS

The first experiments showed preferences for main protein sources in the diets studied, specifically that plant proteins are more accepted than fish meal or egg protein as the main protein source. Several aroma supplements did not modify the acceptance and feed intake markedly.

CONCLUSIONS

The newly developed feeding concept yielded promising preliminary data for long-term studies of energy and nutrient supply under laboratory conditions. However, studies of the fundamental requirements are still needed.

Spontaneous pathology of the common marmoset (Callithrix jacchus) and tamarins (Saguinus oedipus, Saguinus mystax)

BACKGROUND

Marmosets and tamarins are increasingly used in research, but their pathology remains poorly defined compared with Old World primates.

METHODS

Necropsy records of 129 marmosets and 52 tamarins were reviewed; none was used experimentally.

RESULTS

The most common marmoset lesions were dehydration, emaciation, nephritis, colitis, and inanition. The most common tamarin lesions were dehydration, ascites, emaciation, and congestive heart failure. Colitis and heart disease were the most common cause of death in marmosets and tamarins, respectively. Immature marmoset and tamarin deaths often occurred within the first month of life. Immature marmosets usually died from inanition, stillbirth, and colitis; immature tamarins from atelectasis, stillbirth, heart failure, and colitis. Lymphoma was the most common neoplasm for both marmosets and tamarins.

CONCLUSION

The findings were similar to prior reports with differences in frequency and severity. We report the first case of endometriosis in a marmoset.

Identification, evolution, and association study of a novel promoter and first exon of the human NOD2 (CARD15) gene

Mutations in the NOD2 (CARD15) gene predispose to Crohn's disease (CD), a human chronic inflammatory bowel disorder, and can cause Blau syndrome. During an investigation of an apparent correlation between a frameshifting mutation in the canonical first exon of NOD2 of marmoset and tamarin species and their susceptibility to chronic colitis, we found that, contrary to previous reports, the basal levels of NOD2 transcripts in tissues relevant to CD arise from a distinct novel promoter and first exon. The canonical first exon, by contrast, seems to be of negligible transcriptional importance under physiological conditions, and its reading frame has been disrupted twice during primate evolution. Thus the main NOD2/CARD15 protein isoform produced in humans and other primates is 27 amino acids shorter than previously reported, starting at a conserved methionine in exon 2. We show that there is no significant association between variants in the novel NOD2 promoter region and CD.

Background pathology of the common marmoset (Callithrix jacchus) in toxicological studies

Two hundred common marmosets (Callithrix jacchus) from control groups (100 males, 100 females) of toxicological studies were examined histopathologically to evaluate the spectrum of spontaneous lesions in this species. Frequent findings were extramedullary hematopoiesis affecting adrenal glands, liver, kidney and spleen, cystic Brunner's glands in the duodenum, acute or subacute inflammation in the large intestine and gall bladder, renal mineralization and pigmentation, hepatic Ito-cell vacuolation, microgranuloma and glycogen storage, pituitary cysts, C-cell hyperplasia and lymphocytic foci of the thyroid gland, luteal hyperplasia of the ovary and inflammatory cell foci in various organs.

Anemia, myopathy, and pansteatitis in vitamin E-deficient captive marmosets (Callithrix spp.)

Five young adult pet marmosets (Callithrix spp.) were presented with weight loss (5/5); fecal retention (3/5); diarrhea (2/5); impaired locomotion (3/5); anemia (4/4); hypoproteinemia or hypoalbuminemia (3/4); elevations of creatine phosphokinase, lactic dehydrogenase, and alanine aminotransferase (3/4); and renal failure with hypercholesterolemia (2/4). All anemic marmosets had low serum vitamin E levels. The anemia responded to vitamin E and selenium therapy in two marmosets. One of the five marmosets died before presentation, and two others died despite therapy. The two marmosets necropsied had degenerative myopathy, pyogranulomatous pansteatitis, and increased erythrophagocytosis and hemosiderosis. The striated muscle and adipose tissue of both marmosets were negative for coxsackievirus ribonucleic acid by in situ hybridization. These findings suggest that vitamin E deficiency may be involved in the development of anemia, myopathy, and steatitis in callitrichids; however, in some marmosets, underlying diseases such as chronic colitis may have influenced the development of anemia and impaired vitamin E status.

Intestinal microbial patterns of the common marmoset and rhesus macaque

The intestinal microflora of common marmosets and rhesus monkeys were compared by enumerating bacteria from the small and large intestines. Rhesus monkeys had a consistent microflora pattern manifest by higher concentrations of total and Gram-negative aerobic and facultatively anaerobic bacteria, as well as aerobic and anaerobic Lactobacilli, in the large intestine as compared to the small intestine. In contrast, the marmoset microflora were considerably more variable. Approximately two-thirds of the marmosets (designated group A) had an overall profile that resembled the rhesus monkeys, but they had significantly higher concentrations of Gram-negative microflora in their large intestines than the rhesus monkeys. The remaining marmosets (group B) had higher concentrations of bacteria in the small intestine as compared to the large intestine, with the large intestinal concentrations being significantly lower than in the rhesus monkeys and group A marmosets. Moreover, the marmosets did not have detectable levels of aerobic Lactobacilli, and anaerobic Lactobacilli concentrations were significantly lower than in the rhesus macaques. Although it is unknown why microflora differ across species, it is likely that evolutionary adaptations in anatomy and functioning of the gastrointestinal tract influence the concentration and types of bacteria residing as the normal intestinal microflora.

Islet hyperplasia in callitrichids

Five callitrichids (three common marmosets -Callithrix jacchus -, a black tufted-eared marmoset -C. penicillata-, and a saddle-back tamarin -Saguinus fuscicollis) were diagnosed with islet hyperplasia by histopathology and immunohistochemistry. All were privately-owned, unrelated callitrichids ranging from 2- to 4-year-old. Relevant findings were anorexia (3/5), vomiting (2/5), ptyalism (1/5), polyuria/polydipsia (1/5), respiratory distress (1/5), hyperglycemia (2/3) and glycosuria (1/1); hyperglycemia and glycosuria were associated with pregnancy in a common marmoset and resolved after reducing simple carbohydrates in diet. All five animals died, three of them after few premonitory signs; in two cases, other concurrent diseases unrelated to islet hyperplasia were considered the cause of death. Additional animals from two facilities had high weight (4), physical obesity (3), polyuria/polydipsia/polyphagia/uriposia (1), hyperglycemia (1), and/or glycosuria (2). Pathologic findings in the deceased callitrichids were: islet hyperplasia (5/5); hemosiderosis (5/5); lipomatosis (4/5) of several tissues (atria, 3/5; pancreas, gall bladder, intestine, esophagus, and thyroid, 2/5; liver, 1/5); pancreatic necrosis or steatonecrosis, and/or acute pancreatitis (3/5); and vacuolation of hepatocytes and renal tubular cells most likely consistent with hepatorenal lipidosis (2/5). The islets of Langerhans were more numerous and larger than in a control, and morphologically normal in all cases, except in a common marmoset that had a few cells with a foamy cytoplasm and shrunken hyperchromatic or picknotic nucleus. Insulin (5/5), glucagon (3/5), and somatostatin (3/5) immunohistochemistry revealed that most cells stained positively for insulin diffusely in their cytoplasm (5/5) (staining restricted to the vascular pole of b-cells in the control). These findings suggest that obesity, insulin resistance and/or type II diabetes may be implicated and thus a prospective study on these diseases in callitrichids is necessary to determine their etiopathogenesis.

Antioxidant status in a squirrel monkey (Saimiri sciureus) with chronic pancreatitis and degenerative myopathy

A squirrel monkey (Saimiri sciureus) presented with wasting, vomiting and diarrhoea. Haematology revealed elevation of creatinine phosphokinase, lactic dehydrogenase, alanine aminotransferase, amylase and lipase, together with azotaemia and hypoalbuminaemia. Prominent findings were chronic pancreatitis with acinar and ductal plugs, granulomatous and necrotizing peripancreatic steatitis, degenerative myopathy, testicular atrophy, candidiasis and bacterial necrotizing glossitis. Antioxidant analyses revealed low concentrations of serum vitamin E (and apparently A), hepatic selenium and hair zinc. Pancreatitis may have caused malabsorption and maldigestion, associated with deficiency of multiple antioxidants.

Does the haemosiderin iron core determine its potential for chelation and the development of iron-induced tissue damage?

Haemosiderin, the major iron storage protein in tissues of iron-loaded tissues shows heterogeneity with respect to both its iron mineralisation product and associated protein. Such mineralisation products have been characterised by a variety of physical techniques including Mössbauer spectroscopy, electron diffraction and EXAFS, and are closely related to the mineral ferrihydrite. A wide range of iron chelators are being developed for the treatment of abnormal haemoglobinopathies, predominantly beta-thalassaemia, which may show greater chelator efficacy for particular mineralisation products of haemosiderin. Even though the tissue iron loadings achieved in different iron-loading syndromes are similar, e.g. naturally occurring iron loading, genetic haemochromatosis and thalassaemia, it is clear that the iron loading in thalassaemic causes extensive damage. The explanation for this could relate to the distribution of iron within different cell types, predominantly reticuloendothelial, its rate of deposition and the mineralisation product of its haemosiderin iron core, goethite.

An evaluation of the marmoset Callithrix jacchus (sagüi) as an experimental model for the dyslipoproteinemia of human Schistosomiasis mansoni

Human infection with the parasite Schistosoma mansoni is a relatively common occurrence in regions of South America and is associated with liver dysfunction and dyslipoproteinemia. Specifically, the activity of plasma lecithin:cholesterol acyltransferase (LCAT) activity is reduced, the concentration of plasma cholesterol esters falls, phospholipid concentrations are elevated and erythrocyte membranes become cholesterol enriched. Previous studies have utilized rodents (rats and mice) as experimental models to study the dyslipoproteinemia induced by S. mansoni infection. However, the plasma lipoprotein profiles in these animals is very different from humans and infection is not accompanied by decreases in LCAT activity or cholesterol enrichment of their erythrocyte membranes. Here we have evaluated the suitability of the marmoset Callithrix jacchus (sagüi) which is small and readily available in Brazil, as a potential animal model for the study of the dyslipoproteinemia of S. mansoni infections. The plasma lipoprotein compositions and distributions in sagüi, unlike rats or mice, approximate those of man with the LDL representing a major lipoprotein species. The molecular species of phospholipids, cholesterol esters and triglycerides present in sagüi plasma are also very similar to man, whereas those of rats and mice favor the longer chain more unsaturated species, Sagüi, like rodents, can be successfully infected with S. mansoni and after 60 days, this results in a 50% reduction in plasma LCAT activity, an 11% reduction in plasma cholesterol esters, an absolute increase of 46% in plasma phospholipids and an 18% increase in the cholesterol content of erythrocyte membranes. These changes are qualitatively and quantitatively very similar to those previously reported following human infections. Based upon these changes, and the observation that the plasma lipoprotein profile of sagüi and human is similar, we conclude that C. jacchus (sagüi) is an appropriate animal model for the study of dyslipoproteinemia associated with S. mansoni infections.

Hepatic hemosiderosis in non-human primates: quantification of liver iron using different field strengths

Using a non-human primate model of idiopathic hemochromatosis, hemosiderin-induced T2 shortening of the liver was assessed at nine different field strengths over a range of 0.05 to 1.5 Tesla. The 1/T2 values increased linearly with field strength, with all specimens having approximately the same zero-field intercept. The slope of the field increase, termed "field-dependent T2 proton relaxation enhancement (PRE)", appeared to be proportional to the chemically determined tissue iron content, viz. 10.8 s-1T-1(mg Fe/g wet tissue)-1. The correlation between iron content and field-dependent T2 PRE (r = 0.94) was better than the correlation between iron content and 1/T2 values obtained at single field strengths. For livers containing > or = 2 mg Fe/g wet weight, biexponential T2 relaxation behavior emerged at higher field strengths, with the short T2 component (intracellular water) exhibiting a linear dependence of 1/T2 on field, while T2 of the long component (extracellular/sinusoidal water) was nearly field-independent. After maceration of the specimens, all T2 relaxation curves became monoexponential, including those for high iron content at high field strengths. The present data suggest that the use of double-field MR imaging to assess the field-dependent T2 PRE has potential for specific quantification of (liver) tissue iron stores.

Endocrine neoplasia in New World primates

Of 1,106 New World primates necropsied from the National Zoological Park (Washington, D.C.) and the Department of Comparative Pathology, Johns Hopkins University School of Medicine (Baltimore, Maryland) 22 (1.9%) animals were identified with 27 neoplasms. Of this group, nine animals (two females, seven males) had a total of 13 endocrine neoplasms. All animals were adults, with an age range of 2.7-25 years (average, 12.1 years). Seven were Callitrichidae and two were Cebidae. The adrenal gland was the most affected organ, with seven (53.8%) neoplasms, followed by the pituitary and thyroid gland with two (15.4%) cases each, and the pancreas and parathyroid gland with one tumor (7.7%) each. All neoplastic disorders were benign. Immunocytochemistry assays for growth hormone, adrenocorticotropic hormone, prolactin, follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, and chromogranin A were performed on two pituitary neoplasms. Pheochromocytoma was the most frequent neoplasm, representing 5 (38.4%) of the 13 neoplasms. The remaining were thyroid cystadenoma (two, 15.4%), corticotrophic cell pituitary adenoma (two, 15.4%), adrenal ganglioneuroma (one, 7.7%), adrenal cortical adenoma (one, 7.7%), parathyroid chief-cell adenoma (one, 7.7%), and pancreatic islet-cell adenoma (one, 7.7%).