Primary Tupaia Javanica Hepatocyte Culture as an In Vitro Model for Human Hepatitis B Virus Infection

Background: Hepatitis B virus (HBV) infection is still one of the biggest health problems in the world, which could lead to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Treatment for HBV infection has not yet achieved a functional cure. More studies are needed to investigate human HBV (HuHBV), but the scarcity of animal models for HuHBV infection became a barrier. Recently, many studies have shown that Tupaia are suitable for the study of HuHBV. The purpose of this study was to develop a primary tupaia hepatocyte (PTH) culture from T. javanica, a species of Tupaia found in Indonesia, and to prove that HuHBV can replicate in the PTH.Method: In vitro experimental study using PTH isolated from five wild adult T. javanica in Primate Research Center, IPB University. HuHBV was taken from humans with HBsAg and HBV-DNA (+). PTH cells then were infected with HuHBV after reaching 80% confluence. Observation on PTH cells was done everyday for 20 days. Qualitative and quantitative HBsAg were measured using a CMIA while HBV-DNA and cccDNA were measured by RT-PCR.Results: A cytopathic effect was seen on day post infection (DPI)-16. HBsAg and HBV-DNA were detected from DPI-2 until DPI-18, with HBV-DNA level peaked on DPI-12. cccDNA concentration was fluctuating from DPI-2 until DPI-20 with highest level on DPI-16.Conclusion: HuHBV could infect and replicate in PTH from T. javanica can be infected with HuHBV and HuHBV can replicate in the PTH from T. javanica.

Idiopathic Chronic Diarrhea in Rhesus Macaques Is Not Associated with Enteric Viral Infections

While recent changes in treatment have reduced the lethality of idiopathic chronic diarrhea (ICD), this condition remains one of the most common causes of rhesus macaque deaths in non-human primate research centers. We compared the viromes in fecal swabs from 52 animals with late stage ICD and 41 healthy animals. Viral metagenomics targeting virus-like particles was used to identify viruses fecally shed by each animal. Five viruses belonging to the Picornaviridae, one to the Caliciviridae, one to the Parvoviridae, and one to the Adenoviridae families were identified. The fraction of reads matching each viral species was then used to estimate and compare viral loads in ICD cases versus healthy controls. None of the viruses detected in fecal swabs were strongly associated with ICD.

Contribution of adult sex ratio to trauma and reproductive output in large breeding groups of rhesus macaques (Macaca mulatta)

Maintaining stable breeding groups of rhesus macaques (Macaca mulatta) can be challenging due to the complex social dynamics and despotic nature of the species. Trauma from aggression is a common problem in rhesus colonies and can cause social disruption, strain veterinary and animal management resources, and potentially affect reproduction. Previous research has shown that increasing the number of non-natal adult males in a breeding group can improve group stability, reduce trauma, and increase reproduction. Here, we used mixed-effects regression models to examine the effects of sex ratio and other factors on trauma and reproduction at the Yerkes National Primate Research Center using a historical dataset made up of four large rhesus groups over an eleven-year period (2003–2013). As expected, sex ratio was a significant predictor for both trauma and reproduction. However, group age since formation was a stronger predictor of trauma frequency and the amount of space available was a slightly better predictor of reproduction than sex ratio or trauma. These results indicate that improving sex ratios can be a viable management strategy to reduce trauma and improve reproduction, particularly when it is difficult to manipulate the group compositions and/or their housing situations. Reducing trauma is a primary goal for rhesus breeding colonies, as it directly impacts the monkeys' health and psychological well-being. Such improvements are necessary for the ethical treatment and care of the animals themselves, but also to reduce financial burdens and maintain a healthy colony for research purposes.

OpenMonkeyChallenge: Dataset and Benchmark Challenges for Pose Tracking of Non-human Primates

The ability to automatically track non-human primates as they move through the world is important for several subfields in biology and biomedicine. Inspired by the recent success of computer vision models enabled by benchmark challenges (e.g., object detection), we propose a new benchmark challenge called OpenMonkeyChallenge that facilitates collective community efforts through an annual competition to build generalizable non- human primate pose tracking models. To host the benchmark challenge, we provide a new public dataset consisting of 111,529 annotated (17 body landmarks) photographs of non-human primates in naturalistic contexts obtained from various sources including the internet, three National Primate Research Centers, and the Minnesota Zoo. Such annotated datasets will be used for the training and testing datasets to develop generalizable models with standardized evaluation metrics. We demonstrate the effectiveness of our dataset quantitatively by comparing it with existing datasets based on seven state-of-the-art pose tracking models.

The utility of voluntary weighing in captive group-living rhesus macaques (Macaca mulatta)

Bodyweight is an important health and welfare indicator for captive non-human primates (NHPs). Bodyweight can be measured during routine handling procedures, which cause stress. Alternatively, animals can be trained to step onto a scale, but training success varies greatly between individuals. Being able to weigh animals regularly without having to handle or train them is thus desirable for monitoring animal health and welfare. This study investigates the utility, ie the participation, reliability and time investment, of voluntary weighing in captive NHPs living in large social groups. Subjects of the study were 92 rhesus macaques (Macaca mulatta) housed in four social groups at the Biomedical Primate Research Centre in Rijswijk, The Netherlands. A scale was placed in their home enclosure during several sessions. Individuals were unwilling to step onto an unbaited scale. When likeable food items were used to attract individuals to the scale, 68% of them stepped onto the scale. Age and dominance rank did not affect stepping onto the scale, whereas exploratory tendency and social group did. The level of agreement between bodyweight by voluntary weighing and bodyweight measured during sedation was very high. These results show that the majority of rhesus macaques in social groups can be weighed voluntarily and that voluntary weighing is reliable. When optimising and further developing the method, voluntary weighing can form a valuable tool in the captive management of NHPs.

Temperament Predicts the Quality of Social Interactions in Captive Female Rhesus Macaques (Macaca mulatta)

Previous reports suggest that female macaques with greater similarity in emotionality and nervous temperament, as evaluated in a well-established BioBehavioral Assessment (BBA) at the California National Primate Research Center, were more likely to form successful pairs. We tested whether the same measures can also predict the quality of social interactions among 20 female rhesus macaque pairs. We correlated the pairs’ emotionality and nervous temperament scores obtained in infancy and the levels of behaviors recorded systematically during the pairing process years later. Supporting previous findings, partners with similar emotionality scores were more affiliative, and pairs with similar nervous temperament expressed less dominance/submissive behavior. Exploratorily, we found that pairs that were better at processing social information (part of BBA) were also more anxious. Such animals should be prioritized to be introduced in rooms that house calmer, less aggressive animals and provide opportunities for hiding to alleviate their anxiety. Indeed, positive social experiences not only promote animal welfare, but also reduce stress related confounds and unexplained data variability. Therefore, by incorporating the animals’ temperament into the pair configuration process we increase the likelihood of forming high-quality pairs, both in terms of welfare and the research of which they are a part.