Feces are Effective Biological Samples for Measuring Pesticides and Flame Retardants in Primates

Fifty+ years of primate research illustrates complex drivers of abundance and increasing primate numbers

Many primate populations are threatened by human actions and a central tool used for their protection is establishing protected areas. However, even if populations in such areas are protected from hunting and deforestation, they still may be threatened by factors such as climate change and its cascading impacts on habitat quality and disease dynamics. Here we provide a long-term and geographically wide-spread population assessment of the five common diurnal primates of Kibale National Park, Uganda. Over 7 year-long or longer census efforts that spanned 52 years, our team walked 1466 km, and recorded 480 monkey groups. Populations were generally relatively stable with a few exceptions, for which no apparent causative factors could be identified. This stability is unexpected as many ecological changes documented over the last 34+ years (e.g., decreasing food abundance and quality) were predicted to have negative impacts. Populations of some species declined at some sites but increased at others. This highlights the need for large, protected areas so that declines in particular areas are countered by gains in others. Kibale has large areas of regenerating forest and this most recent survey revealed that after 20+ years, forest regeneration in many of these areas appears sufficient to sustain sizeable primate populations, except for blue monkeys that have not colonized these areas. Indeed, the average primate abundance in the regenerating forest was only 8.1% lower than in neighboring old-growth forest. Thus, park-wide primate abundance has likely increased, despite many pressures on the park having risen; however, some areas in the park remain to be assessed. Our study suggests that the restoration, patrolling, and community outreach efforts of the Uganda Wildlife Authority and their partners have contributed significantly to protecting the park and its animals.

Biotransformation, Bioaccumulation, and Bioelimination of Triphenyl Phosphate and Its Dominant Metabolite Diphenyl Phosphate In Vivo

Aryl phosphorus flame retardants (aryl-PFRs), such as triphenyl phosphate (TPHP) and diphenyl phosphate (DPHP), are widely used worldwide. Understanding the fates of aryl-PFRs in vivo is crucial to assessing their toxicity and the risks they pose. Seven TPHP metabolites, including Phase I hydrolysis and hydroxylation and Phase II glucuronidation products, were identified in C57BL/6J male mice following subacute dietary exposure to aryl-PFRs (70 μg/kg body weight (bw)/day) for 7 days. TPHP was almost completely metabolized by mice (∼97%), with DPHP the major metabolite formed (34%-58%). In addition, mice were exposed to aryl-PFRs (7 μg/kg bw/day) for 12 weeks. Both TPHP and DPHP occurred at higher concentrations in the digestive tract (intestine and stomach), liver and heart. The total concentration of DPHP in all organs was 3.55-fold greater than that of TPHP. Recovery analysis showed that the rate of TPHP elimination from mouse organs reached 38%, while only 3%-5% of DPHP was removed, suggesting that the rates of degradation and elimination of DPHP were slower than TPHP and its bioaccumulation potential was higher. These results highlight the critical role of DPHP in the biotransformation, bioaccumulation, and bioelimination of TPHP, providing valuable insights into the fate of aryl-PFRs in vivo.

Measuring mantled howler monkey (Alouatta palliata) testes via parallel laser photogrammetry: Expanding the use of noninvasive methods

Parallel laser photogrammetry (PLP), which consists of attaching two or three parallel laser beams at a known inter-beam distance to a camera, can be used to collect morphological measurements of organisms noninvasively. The lasers project onto the photo being taken, and because the inter-beam distance is known, they act as a scale for image analysis programs like ImageJ. Traditionally, this method has been used to measure larger morphological traits (e.g., limb length, crown-rump length) to serve as proxies for overall body size, whereas applications to smaller anatomical features remain limited. To that end, we used PLP to measure the testes of 18 free-living mantled howler monkeys (Alouatta palliata) at La Selva Biological Station, Costa Rica. We tested whether this method could reliably measure this relatively small and globular morphology, and whether it could detect differences among individuals. We tested reliability in three ways: within-photo (coefficient of variation [CV] = 4.7%), between-photo (CV = 5.5%), and interobserver (intraclass correlation = 0.92). We found an average volume of 36.2 cm3 and a range of 16.4-54.4 cm3, indicating variation in testes size between individuals. Furthermore, these sizes are consistent with a previous study that collected measurements by hand, suggesting that PLP is a useful method for making noninvasive measurements of testes.

Complementarity of plasma and stool for the characterization of children's exposure to halogenated flame retardants: Update on analytical methods and application to a Canadian cohort

Sixteen halogenated flame retardants including Polybrominated diphenyl ethers (PBDEs), Dechlorane-like compounds, and emerging halogenated flame retardants were measured in stool and plasma samples from children aged 8.9-13.8 years old. Samples were obtained from a Canadian cohort investigating the effect of contaminants on children's neurodevelopment in the Estrie region, Québec, Canada. The method for stool analysis developed for this study showed good recovery for all targeted compounds (73%-93%) with associated relative standard deviation (RSD) in the range of 16.0%-30.7% for most compounds except for the thermosensitive BDE209, OBTMBI, and BTBPE, which showed slightly higher RSD, i.e., 49.3%, 37.2%, and 34.9% respectively. Complementarity investigation of stool and blood samples allowed us to better characterize human exposure to these halogenated flame retardants. Exposure patterns differed significantly between stool and blood, notably in the relative abundance of BDE47, BDE100, BDE99, and BDE153 and the detection frequencies of BDE209, syn-DP, anti-DP, and DBDPE. There was no correlation between the two matrices' PBDEs concentration levels except for BDE153 (rho = 0.44, p < 0.01). Our results indicate that future epidemiological studies may benefit from the use of stool as a complementary matrix to blood, especially investigations into chemical impacts on the gut microbiome. Results also revealed that children from the GESTE cohort, an Eastern Canadian semi-rural cohort, are exposed to both historical and emergent flame retardants.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

Primate population dynamics in Ngogo, Kibale National Park, Uganda, over nearly five decades

Many anthropogenic-driven changes, such as hunting, have clear and immediate negative impacts on wild primate populations, but others, like climate change, may take generations to become evident. Thus, informed conservation plans will require decades of population monitoring. Here, we expand the duration of monitoring of the diurnal primates at Ngogo in Kibale National Park, Uganda, from 32.9 to 47 years. Over the 3531 censuses that covered 15,340 km, we encountered 2767 primate groups. Correlation analyses using blocks of 25 census walks indicate that encounters with groups of black and white colobus, blue monkeys, and baboons neither increased nor decreased significantly over time, while encounters with groups of redtail monkeys and chimpanzees marginally increased. Encounters with mangabeys and L'Hoesti monkeys increased significantly, while red colobus encounters dramatically decreased. Detailed studies of specific groups at Ngogo document changes in abundances that were not always well represented in the censuses because these groups expanded into areas away from the transect, such as nearby regenerating forest. For example, the chimpanzee population increased steadily over the last 2 + decades but this increase is not revealed by our census data because the chimpanzees expanded, mainly to the west of the transect. This highlights that extrapolating population trends to large areas based on censuses at single locations should be done with extreme caution, as forests change over time and space, and primates adapt to these changes in several ways.

Associations between faecal chemical pollutants and hormones in primates inhabiting Kibale National Park, Uganda

While anthropogenic pollutants are known to be a threat to primates, our understanding of exposure to pollutants in situ and their sub-lethal effects is still limited. We used non-invasive biomonitoring to examine associations between faecal concentrations of 97 chemical pollutants and faecal hormone metabolites of cortisol and oestradiol in four primate species inhabiting Kibale National Park, Uganda (chimpanzees-Pan troglodytes, olive baboons-Papio anubis, red colobus-Piliocolobus tephrosceles and red-tailed monkeys-Cercopithecus ascanius). Across all species (n = 71 samples), results demonstrated positive associations of organochlorine pesticides (OCPs) (β = 0.143, p = 0.020) and organophosphate esters (β = 0.112, p = 0.003) with cortisol in adult females. Additionally, we observed positive associations of OCPs (β = 0.192, p = 0.013) and brominated flame retardants (β = 0.176, p = 0.004) with cortisol in juveniles. Results suggest that cumulative pesticides and flame retardants are disruptive to endocrine function in these populations, which could have implications for development, metabolism and reproduction. Our study further demonstrates that faeces can be an important, non-invasive matrix for examining pollutant-hormone associations in wild primates and other critical wildlife populations.

DBDPE upregulates NOD-like receptor signaling to induce NLRP3 inflammasome-mediated HAECs pyroptosis

Decabromodiphenyl ethane (DBDPE), a typical new brominated flame retardant (BFR), is a widespread new pollutant in the environment. Several studies and our previous studies have found that DBDPE can cause aortic endothelial injury and aortic endothelial cell pyroptosis, whereas the molecular mechanism involved has not been elucidated. In this study, we exposed human aortic endothelial cells (HAECs) to 25 μmol/L of DBDPE and analyzed the gene expression profiles by Affymetrix PrimeView™ Human Gene Expression Chip. The results showed that 886 genes were differentially expressed in the DBDPE exposure group. Enrichment analyses revealed that differentially expressed genes were mainly enriched in the inflammatory response and NOD-like receptor signal pathway. Gene-gene functional interaction analyses and crossover genes and pathways analyses found that the NOD-like receptor signal pathway may be involved in regulating NLRP3 and IL-18. We found that NOD2 cannot interact with NLRP3 directly through an immunoprecipitation experiment. Thus, we construct the RIPK2 knockdown HAECs cell line to repress the NOD-like receptor signaling and further study the mechanism of DBDPE-activated NLRP3 inflammasome to induce HAECs pyroptosis. The results showed that RIPK2 knockdown could repress DBDPE-induced NOD-like receptor signaling pathway upregulation, inhibit NLRP3 inflammasome activation, and decrease HAECs pyroptosis. In addition, RIPK2 knockdown decreased the ROS generation in HAECs induced by DBDPE. And NAC pretreated HAECs inhibited DBDPE-induced NLRP3 inflammasome activation and HAECs pyroptosis. These results demonstrated that DBDPE upregulated NOD-like receptor signaling to induce ROS generation and, in turn, activated NLRP3 inflammasome, leading to HAECs pyroptosis.

Female reproduction and viral infection in a long-lived mammal

For energetically limited organisms, life-history theory predicts trade-offs between reproductive effort and somatic maintenance. This is especially true of female mammals, for whom reproduction presents multifarious energetic and physiological demands. Here, we examine longitudinal changes in the gut virome (viral community) with respect to reproductive status in wild mature female chimpanzees Pan troglodytes schweinfurthii from two communities, Kanyawara and Ngogo, in Kibale National Park, Uganda. We used metagenomic methods to characterize viromes of individual chimpanzees while they were cycling, pregnant and lactating. Females from Kanyawara, whose territory abuts the park's boundary, had higher viral richness and loads (relative quantity of viral sequences) than females from Ngogo, whose territory is more energetically rich and located farther from large human settlements. Viral richness (total number of distinct viruses per sample) was higher when females were lactating than when cycling or pregnant. In pregnant females, viral richness increased with estimated day of gestation. Richness did not vary with age, in contrast to prior research showing increased viral abundance in older males from these same communities. Our results provide evidence of short-term physiological trade-offs between reproduction and infection, which are often hypothesized to constrain health in long-lived species.

A Literature Review of Unintentional Intoxications of Nonhuman Primates

Simple Summary

This report is an overview of the published veterinary literature on unintentional poisonings in wild and captive nonhuman primates (NHP). Selected intoxications will be described with emphasis on the clinical signs, laboratory, and main postmortem findings as well as the available treatment options. Mostly, NHP died suddenly and unexpectedly without showing any preceding clinical signs. The (presumptive) diagnosis of a poisoning was mostly made postmortem by laboratory testing of post-mortem fluid, tissue samples, and stomach contents. From these reports, we concluded that the toxic threats to wild NHP are different to those of captive NHP because of the environment in which they live. We also concluded that a poisoning or an intoxication should be part of a differential diagnosis when a NHP presents with clinical signs that cannot be linked to a known disorder or dies suddenly with no preceding clinical signs.

Abstract

Reports of unintentional intoxications in nonhuman primates (NHP) are few and an up-to-date review of such intoxications in NHP is lacking. We reviewed the published veterinary literature on unintentional intoxications in wild and captive NHP in order to provide a useful resource on known toxic agents of NHP for veterinarians, caregivers, and researchers who work with NHP. To these ends, we first conducted a literature search for books, book chapters, peer-reviewed publications, conference proceedings, and newsletters in academic literature databases such as Google Scholar, PubMed, BioOne Complete, and Web of Science using the words and word combinations such as heavy metals, pesticides, poisonings, and nonhuman primates. We then evaluated the search results for those reports that we considered as clinically relevant and then classified them according to the toxic agent. We identified lead, zinc, phytotoxins, pesticides, botulinum toxin, polychlorinated biphenyls, and snake and spider venoms as the main toxic agents in wild and captive NHP. We concluded that the toxic threats to wild NHP are different to those of captive NHP because of the environment in which they live. We recommend that an intoxication should be part of a differential diagnosis when a NHP presents with clinical signs that cannot be linked to a known disorder or dies suddenly with no preceding clinical signs. In cases of the former, laboratory testing for known toxins and pollutants should be conducted. In cases of the latter, a thorough postmortem examination, together with extensive laboratory testing, for known toxins and environmental pollutants in all tissues and organs should be performed.

Biodegradation of decabromodiphenyl ethane (DBDPE) by white-rot fungus Pleurotus ostreatus: Characteristics, mechanisms, and toxicological response

Decabromodiphenyl ethane (DBDPE) can pose a potential toxic threat to human beings and the environment. P. ostreatus, as one of the typical white-rot fungi, can effectively degrade various refractory pollutants. The biodegradable characteristics of DBDPE by P. ostreatus, as well as the mechanisms, and toxicological response were investigated in this study. The removal rate reached 47.73% and 43.20%, respectively, for 5 and 20 mg/L DBDPE after 120-h degradation by P. ostreatus. As a coexisting substance, Pb could inhibit the biodegradation. It is found that both the intracellular enzyme (P450) and extracellular enzymes (manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase (Lac)) played a very important role in the biodegradation of DBDPE, of which Lac dominated the degradation. The toxic response was monitored during the degradation. The activities of SOD and CAT were enhanced to eliminate excess ROS in P. ostreatus triggered by DBDPE. In addition, debromination, hydroxylation, and oxidation were inferred as the main degradation pathways preliminarily. The findings provide a theoretical basis for the application of microbial degradation of DBDPE contamination.

Chemical pollution as a driver of biodiversity loss and potential deterioration of ecosystem services in Eastern Africa: A critical review

Chemical pollution, i.e. the release of anthropogenic chemical substances into the environment, is a driver of biodiversity loss. Although this issue has been widely investigated in high-income countries of temperate regions, there is a lack of data for tropical areas of middle- or low-income countries, such as those in Eastern Africa. Some of the world’s richest biomes that are affected by multiple pressures, including chemical pollution, are hosted in this macro-region. However, few studies have addressed the impact of the release of anthropogenic chemical pollutants on the biodiversity, and the related potential implications for the deterioration of ecosystem goods and services in this area. A contribution in systemising the scientific literature related to this topic is, therefore, urgently needed. We reviewed studies published from 2001 to 2021, focusing on the chemical pollution impact on Eastern African wildlife. Despite an extensive literature search, we found only 43 papers according to our survey methods. We focused on wildlife inhabiting terrestrial ecosystems and inland waters. According to our search, Kenya and Uganda are the most represented countries accounting for about half of the total number of reviewed articles. Moreover, 67.4% of the studies focus on inland waters. The spread of anthropogenic chemicals into tropical areas, e.g. Eastern Africa, and their effects on living organisms deserve greater attention in research and politics. We report a weak increasing trend in publishing studies addressing this topic that might bode well. The combined effort of science and governments is crucial in improving the management of chemical pollutants in the environment for achieving the goals of biodiversity conservation.