Data on the circulation of hepatitis E virus (HEV) in primatology centers are limited, as are the knowledge of natural course of spontaneous HEV infection in monkeys. The aim of the study was to assess dynamic changes in HEV seroprevalence among monkeys of the Kurchatov Center of Medical Primatology over the last ten years and molecular and clinical analysis of sporadic cases of HEV infection in monkeys kept in the primate center. Serum and fecal samples from 379 rhesus macaques and 179 cynomolgus macaques collected between 2014 and 2024 were tested to assess virological, hematological, and biochemical markers of HEV infection. Anti-HEV IgG antibody detection rates increased sharply from 28.2% in 2014-2016 to 68.9% in 2021-2024 in rhesus macaques and from 5.6% to 70.9% in cynomolgus macaques. Phylogenetic analysis of HEV sequences from macaques with sporadic infection showed their identity to HEV genotype 4 sequences from cynomolgus macaques imported from Vietnam in 2017. Sporadic HEV infection in macaques was accompanied by a slight increase in aspartate aminotransferase (AST) levels and, in some animals, elevated levels of malondialdehyde (MDA). A latent epizootic of HEV-4 infection was presumably due to the waterborne transmission of the virus that was initially introduced into the primate center with monkeys imported from Vietnam. Regular testing of quarantined animals for markers of HEV infection, as well as the elimination of a single flow-through drinking water supply system and the use of individual equipment for cleaning cages, may be effective measures to contain the spread of HEV in primate centers.
This is the story of how I became a primatologist, and the major research projects and activities in my career specializing in the ecology, behavior, and conservation of gibbons. After graduate training in zoology, I spent two years as an officer in the U. S. Army's Medical Service Corps and was assigned to the SEATO Medical Research Laboratory in Bangkok. My assignments included caring for a colony of captive gibbons (Hylobates lar) released on an island to produce animals for experimental research on diseases. After my army career, I relocated to Thailand in 1973 and my interests turned to wild gibbons in the forests of Thailand. My career in Thailand was spent teaching ecology in the biology department of Mahidol University. After retirement, I continued working at BIOTEC, National Science and Technology Development Agency, and established a large forest dynamics research plot in the Mo Singto gibbon study site in Khao Yai National Park. Research carried out in Khao Yai included study of the ecology and social behavior of gibbons, plant seed dispersal, and relations between Hylobates lar and H. pileatus, whose distributions overlap in a small area of the park. I describe some of the conservation activities I have been involved in, which include development of sampling techniques for gibbon populations, survey of wild gibbons, reintroduction of gibbons, and publication of books on primates for children. Finally, I offer some recommendations on how to become a primatologist.
Toxoplasmosis is one of the most prevalent parasitic infections in animals and humans worldwide, attracting the attention of many researchers who, in recent decades, have identified the sources of Toxoplasma gondii infections to optimize the adoption of preventive measures. In previous studies, it has been found that humans are infected mainly by consuming raw or undercooked meat or by ingesting fruits, vegetables, seafood or water contaminated with oocysts of this protozoan. Soil contaminated with T. gondii oocysts is a source of infection for animals and humans, but it has rarely been directly detected due to the lack of appropriate methods. Given that toxoplasmosis is a widespread zoonosis of great public health importance, we investigated the occurrence of T. gondii in the soil of 30 enclosures housing different animal species at the Bauru Zoo, São Paulo, by amplifying the protozoan's DNA using conventional polymerase chain reaction (cPCR). The cPCR for T. gondii was performed using primers TOX4 and TOX5, which amplify 529 bp. Thus, we observed that soil samples from two enclosures of African primates of the species Papio papio (Guinea Baboon) and Papio hamadryas (Hamadryas Baboon) were positive by PCR for T. gondii, an unprecedented result in the literature.
Tongue squamous cell carcinoma (TSCC) is a typical and prevalent neoplasm in non-human primates (NHPs). However, comprehensive pathological and immunohistochemical analyses of TSCC in rhesus monkeys have been infrequently documented. Three rhesus monkeys with TSCC were sourced from the same breeding facility. Laboratory tests, gross observation of the lesion tissue, and human papillomavirus content testing using real-time fluorescence PCR method of the animals were carried out. The animals underwent necropsy for examination of tissues and organs, followed by histopathological and immunohistochemical analysis. The clinical manifestations observed across all animals included salivation, swelling, sclerosis, and ulceration of the tongue. All three rhesus monkeys were euthanized due to deteriorating health conditions. No abnormalities were noted in other organs during post-mortem examination except for their tongues. Histopathological examination revealed an invasive tumor characterized by nests of polygonal cells within the stroma, accompanied by significant desmoplastic reactions and occasional cancerous beads. All cases demonstrated positive immunolabeling for p63, CK5/6, p40, CK19, CK7, and CK20 via immunohistochemistry (IHC) analysis. The clinical manifestations and pathological examination of the three cases were consistent with the characteristics of highly differentiated squamous cell carcinoma. Additionally, immunohistochemical analysis revealed positive expression of p63, CK5/6, p40, CK19, CK7, and CK20. In three cases, the results of human papillomavirus were negative. This study provides an important reference for the diagnosis of TSCC in rhesus monkeys.
Colon cancer death toll due to metastasis is expected to rise. Extracellular vesicles are signalling molecules which can regulate communication between cells and either inhibit or promote cancer metastasis. Extracellular vesicles from adipose mesenchymal stem cells of Macaca fascicularis were obtained from previous research. Various concentrations of extracellular vesicles (5 μg/mL, 10 μg/mL, and 20 μg/mL) were applied to colon cancer cell line WiDr in a transwell invasion assay. CXCR3 gene expression analysis was done using RT-qPCR. Application of extracellular vesicles successfully inhibited colon cancer invasion with decrease of number of invasive cells with increase in concentration. There was no statistical difference between cells treated with 10 μg/mL and 20 μg/mL of extracellular vesicles. Colon cancer cells treated with extracellular vesicles show upregulation of CXCR3A and CXCR3B gene expression compared to negative control. Extracellular vesicles inhibit colon cancer cell invasion through upregulation of CXCR3B expression.
The nonhuman primate (NHP) model has been a cornerstone in the development of effective therapeutic and prophylactic interventions for HIV-1 infection. Yet, despite promising results in this key preclinical setting, major efficacy trials of HIV vaccines have failed to exhibit sufficient protection to meet their endpoint efficacy criteria. Similarly, the recent Antibody-Mediated Prevention (AMP) trials (HVTN 703, 704), which tested the ability of passive immunization with the broadly neutralizing antibody VRC01, also failed to meet predetermined overall efficacy criteria. Cumulatively, both active and passive vaccination regimens that have demonstrated the ability to provide protection in NHPs have not provided sufficient benefits in clinical field trials, raising questions about how to optimally model the challenging clinical reality facing HIV-1 vaccine developers. Here, with a goal of highlighting means whereby gaps might be addressed, we discuss some factors that may influence consistency between NHP experiments and translation between clinical and preclinical settings in both active and passive vaccine regimens. We conclude that results from the AMP trials provide a key benchmark that has high value in gauging the clinical prospects of humoral immune responses induced by vaccines or provided by passive antibody prophylaxis. The promise of new knowledge gained through carefully designed testing of new interventions and therapeutics motivates continued exploration of means to model humoral immunity to HIV-1 in preclinical models.
Canine distemper virus (CDV) has markedly expanded its known host range over the recent past decades. CDV infection has been reported in old-world primates of the genus Macaca, with reports between the 1980s and 2008 in Japan and China. Over the past months, independent research groups in Brazil reported an individual case and two outbreaks of CDV infection affecting free-ranging marmosets (Callithrix spp.) from different regions of the country. Clinical manifestations, pathological changes and viral tropism in neotropical primates are discussed. Furthermore, potential consequences on conservation of endangered species of neotropical primates and potential host adaptation to primates that may eventually favor human infections are also discussed. It is still unclear whether these independent reports of CDV infection in neotropical primates in such a short period of time may be due to an epizootic situation or to an increased efficiency of the surveillance system in place in Brazil.
Suppressing estradiol (E2) during baboon pregnancy lowers offspring skeletal muscle capillary density, vital for insulin-mediated glucose uptake, and induces insulin resistance. We examined whether E2 deprivation also impairs microvascular flow and cardiac function. Offspring of untreated baboons, letrozole-treated baboons, or letrozole plus E2 (maternal s.c. injections during the second half of gestation) underwent contrast-enhanced microbubble ultrasonography to quantify microvessel flow and echocardiography to assess cardiac performance. Letrozole reduced maternal serum E2 by 95% (p < 0.01). In letrozole offspring, microbubble flux rate (β) fell 55% (p < 0.02), replenishment was 5 s slower (p < 0.03), and microvessel flow declined 40% (p = 0.05); all were restored by added E2. Indices of systolic (isovolumic contraction), diastolic (isovolumic relaxation), global performance (Tei index), and cardiac output were unchanged. Prolonged gestational E2 deprivation programs a reduction in microvascular flow without altering cardiac function; maternal E2 prevents this, supporting E2's role in optimizing postnatal perfusion and metabolic health.
Cynomolgus macaques are widely used in biomedical research, yet the hybridisation between the subspecies M. f. fascicularis (Mff) and M. f. aurea (Mfa), and introgression from another species M. mulatta (Mm) may affect the research outcomes. DNA barcoding targeting COI mtDNA, as well as phylogenetic, pairwise distance and statistical analyses were employed to examine the relationships between Mff, Mfa and Mm using 52 newly sequenced and 59 public DNA barcodes representing 17 Macaca taxa and seven species groups. DNA barcoding delineated the Macaca taxa, revealing genetic distinctions between Mff and Mfa greater than between Mff and Mm, as well as delineating geographical populations. This underscores the need for verification of laboratory individuals, besides genetic management of breeding colonies, as genetic differences can influence disease susceptibility and drug trial outcomes. DNA barcoding offers a rapid, cost-effective tool to ensure appropriate selection and genetic management of laboratory individuals used in biomedical research.
Callitrichid primates Saguinus bicolor and Saguinus midas from urban accidents in peri-urban forests from Central Amazon were necropsied. Analysis of thoracic and peritoneal fluid showed that 56.5% (13/23) of S. bicolor individuals and 13.3% (4/30) of S. midas individuals had the presence of Dipetalonema and Mansonella (Tetrapetalonema) microfilariae.
Despite extraordinary global progress in the prevention and treatment of HIV, pediatric HIV remains a significant and under-addressed component of the global epidemic. In her keynote presentation at the Pediatric Nonhuman Primate (NHP) Workshop in October 2024, Dr. Ann Chahroudi delivered a comprehensive and compelling argument for the essential role of pediatric NHP models in translational HIV research. Her talk (summarized below) provided a detailed overview of how infant monkeys have contributed uniquely to our understanding of HIV pathogenesis, immune development, and therapeutic strategies in early life-and why continued investment in these models is critical for advancing pediatric HIV prevention, treatment, and cure.
The Bonnet macaque (Macaca radiata radiata) is a highly adaptive, anthropocentric, and commensal species that inhabits urban habitats with provisioned dietary habits. It is a subject of various scientific studies, particularly concerning its hematological and serum biochemical parameters. However, comprehensive baseline datasets are scarcely available, with existing data mostly derived from lab-maintained animals rather than wild individuals. The objective of this study is to establish reference values for hematological and serum biochemical parameters of Bonnet macaques living in Bengaluru urban ecological conditions with varied dietary habits. The study area lies between 12°58' N and 13°00' N latitude and 77°30' E and 77°40' E longitude. Blood samples were collected with KFD permission from urban macaques across different parts of the city by trained veterinary professionals following all due standard protocols and ethics. The results revealed crucial comparative differences from the available literature data and across age and sex groups. The Shapiro-Wilk test was performed to determine the normal distribution of the dataset, and the results obtained are variable-specific. The established reference values will enable more accurate interpretation of hematological and serum biochemistry values specific to urban macaque populations.
Reproduction in captive chimpanzees (Pan troglodytes) can be controlled by the insertion of intrauterine devices (IUDs) for females who do not reliably take oral contraceptives. Previous literature describes the use of improvised devices made from syringe cases as a speculum to accommodate the depth of the vaginal vault. Copper IUDs (model T380A) were inserted in two sanctuary-housed chimpanzees. A disposable human small-sized vaginal speculum (Welch Allyn KleenSpec) with an illumination system provided a good view of the cervix. A 3/4 mm dilator and a uterine sound aided insertion. After multiple rounds of dilation, the uterine sound was still necessary to manipulate the IUD to the fundus of the uterus. Correct placement was confirmed by ultrasonography and radiology. Inserting IUDs in chimpanzees can prove challenging. Having appropriate equipment available, such as varied sizes of speculums and dilators, is crucial. Gynecologists and ultrasonographers with experience inserting IUDs in humans can help ensure correct placement.
This study aimed to conduct a serological and molecular survey of Toxoplasma gondii in nonhuman primates under human care in the state of Rio de Janeiro. MAT and qPCR were performed on 199 serum and blood samples collected from animals at the following locations: BioParque Zoo, Volta Redonda Municipal Zoo, Wildlife Rehabilitation Center, Laboratory Animal Facility of the Federal University of Rio de Janeiro, and the Rio de Janeiro Primatology Center. Risk factors for T. gondii infection were also assessed. qPCR analysis revealed DNA amplification of T. gondii in one animal of the species Alouatta caraya. MAT analysis showed 100% seropositivity among Old World primates and 42.62% among New World primates. At locations where raw meat is included in the diet and water is unfiltered, animals were found to be 10.88 times more likely to test seropositive.
UC-MSCs appear to be a viable option for stem cell-based treatment. Cynomolgus monkeys, with their psychological and genetic parallels to humans, are essential models for medical study and development. Hypoxia is a basic characteristic of angiogenesis, glucose metabolism, and cell proliferation and survival in both healthy and pathological individuals. This study aimed to develop and characterize UC-MSCs requirements derived from the cynomolgus monkey. We have successfully developed UC-MSCs derived from Mf under hypoxic conditions. Mf UC-MSCs was cultured from the WJ area. Our Mf UC-MSCs have developed into adipocytes, osteocytes, and chondrocytes. The protein of the biomarker MSC was expressed in our hypoxic precondition Mf UC-MSCs and the mRNA expression levels of ERK1/2, AKT1, and HIF-1 alpha increased in the hypoxic condition compared to the normoxic and control groups. The JNK and NFκB genes were decreased in the hypoxic group. Interestingly, our hypoxic Mf UC-MSCs suppressed IL-6 expression. These findings show that preconditioned Mf UC-MSCs produce anti-inflammatory properties, making them potential candidates for regenerative medicine. Their response to hypoxia is crucial for developing targeted therapies to enhance regenerative capabilities in conditions such as ischemic injury and neurodegeneration.
The primate gastrointestinal tract is home to bacteria, which may be associated with its habitat. In Malaysia, wild stump-tailed macaques (Macaca arctoides) are found solely in the northern region of Peninsular Malaysia. No information is currently available regarding the intestinal microbiota of wild or captive Malaysian stump-tailed macaques. In this study, a fecal metabarcoding approach was utilized to determine the gut microbiome composition of wild and captive M. arctoides and how these microbial communities respond to the host's external environment. To elucidate these relationships, 16S rRNA was amplified and sequenced using the MiSeq platform, with 300 paired-end sequences. We identified 18 phyla, 38 orders, 46 families, 76 genera, and 131 species in the stump-tailed macaque samples. The most prevalent bacterial families in the gut of M. arctoides were Firmicutes (4.69%), Spirochaetes (2.87%), and Proteobacteria (2.40%). Our analysis did not reveal any substantial differences between the habitat environment and gut microbiome composition in M. arctoides. Nonetheless, to the best of our knowledge, this study is the first to document the gut microbiome of the wild M. arctoides population in Peninsular Malaysia. Future studies are required to explore and better understand potential zoonotic pathogens harbored in stump-tailed macaques.
Acclimation involves physiological adjustments to environmental factors such as geographic origin and housing conditions. Proper acclimation is essential for animal welfare and ensuring the reliability of experimental data. However, the long-term acclimation of cynomolgus macaques has not been systematically examined. Therefore, we compared serum chemistry values between cynomolgus macaques from Vietnam and housed in Laos. The Vietnamese-imported macaques were then monitored while housed indoors at the Korean Institute of Toxicology (KIT), Korea for 13 months. Serum biochemical values were compared between male and female Vietnam-imported and Laotian-housed cynomolgus macaques (n = 68 each). Additionally, the haematology, serum biochemistry, and body weight of male and female Vietnam-imported macaques (n = 70 each) were followed up for 405 days while they were housed in KIT. Significant differences in alkaline phosphatase and creatine kinase levels were observed between the two populations. Over the 13-month follow-up in Vietnamese-imported macaques, gradually and continuously increasing body weights were observed, with a temporary decline during the first 12 days following relocation to the indoor facility in male macaques. Environmental factors of exporting countries may influence the physiological baseline of cynomolgus macaques, and long-term adaptation is needed when they are translocated from outdoor housing to an indoor closed system.
A hybrid workshop entitled "NHP Models for HIV Prevention and Treatment: Towards Developing Pediatric Formulations" was organized by the Prevention Sciences Program (PSP) of the Division of AIDS (DAIDS) within the National Institute of Allergy and Infectious Diseases (NIAID), with special assistance from Advanced Biosciences Laboratories Inc. (Rockville, Maryland) and the Tulane National Biomedical Research Center (Covington, Louisiana). The event was held on October 22, 2024, in New Orleans and attracted participants from academia, industry, and government agencies, and included attendees from the 41st Annual Symposium on Nonhuman Primate Models for AIDS.
Ventricular septal defect (VSD) is a congenital defect that is frequently observed in humans. We report the sudden death of an infant chimpanzee due to a congenital undiagnosed VSD. During necropsy, the examination of the heart revealed a VSD, dilatation of the left ventricle and myocardial hypertrophy of the right ventricle.
Nonhuman primates (NHPs) have emerged as an indispensable model for studying HIV pathogenesis, vaccines, and therapies. The development of chimeric Simian/Human immunodeficiency viruses (SHIVs) has been constructed by inserting HIV-1 Env into the SIV (usually SIVmac239) backbone, and these have proved essential for evaluating HIV neutralizing antibody dynamics and efficacy in vivo, making studies testing the protective efficacy of human broadly neutralizing monoclonal antibodies (bNAbs) in nonhuman primates possible. The original constructs have been improved in several new SHIV strains to improve binding of the Env to the macaque CD4 receptor by an additional mutation, and further improvements continue to be made. Even with some limitations, NHP models using SHIV infection have contributed substantially to the advancement of HIV bNAb use in both adult and pediatric settings.