Studies of nonhuman primates: key sources of data on zoonoses and microbiota

Zebrafish (Danio rerio) as a Model System to Investigate the Role of the Innate Immune Response in Human Infectious Diseases

The zebrafish (Danio rerio) has emerged as a valuable model for studying host-pathogen interactions due to its unique combination of characteristics. These include extensive sequence and functional conservation with the human genome, optical transparency in larvae that allows for high-resolution visualization of host cell-microbe interactions, a fully sequenced and annotated genome, advanced forward and reverse genetic tools, and suitability for chemical screening studies. Despite anatomical differences with humans, the zebrafish model has proven instrumental in investigating immune responses and human infectious diseases. Notably, zebrafish larvae rely exclusively on innate immune responses during the early stages of development, as the adaptive immune system becomes fully functional only after 4-6 weeks post-fertilization. This window provides a unique opportunity to isolate and examine infection and inflammation mechanisms driven by the innate immune response without the confounding effects of adaptive immunity. In this review, we highlight the strengths and limitations of using zebrafish as a powerful vertebrate model to study innate immune responses in infectious diseases. We will particularly focus on host-pathogen interactions in human infections caused by various bacteria (Clostridioides difficile, Staphylococcus aureus, and Pseudomonas aeruginosa), viruses (herpes simplex virus 1, SARS-CoV-2), and fungi (Aspergillus fumigatus and Candida albicans).

Assessment of the Risks of Zoonotic Infection at the Primatology Centre of the Interdisciplinary Medical Research Centre of Franceville in Gabon

BACKGROUND

Non-human primate (NHPs) conservation sites could be sites of exchange of pathogens involved in infectious diseases. It is important to assess the potential risks associated with this type of structure. The objective of this study was to carry out a risk assessment of the Primatology Centre housed in the Interdisciplinary Centre for Medical Research of Franceville (CIRMF).

METHODS

A questionnaire was administered to the centre's staff to assess the risk associated with each workstation, followed by a review of the various pathogens identified in NHPs. The data were analysed using two diagrams: the Kiviat diagram and the Pareto diagram.

RESULTS

Based on our results, a variety of pathogens such as viruses, bacteria and parasites, potentially transmissible to humans, were described in the NHPs at the Primatology Centre of CIRMF. The position most exposed to zoonotic risks was that of animal handlers.

CONCLUSION

The Primatology Centre of CIRMF is a potential transfer site for the transfer of zoonotic agents. To avoid the risk of parasite exchange between staff and animals, the implementation of biosecurity measures is essential.

Zoonotic pathogens in wild Asian primates: a systematic review highlighting research gaps

Introduction

Ongoing global changes, including natural land conversion for agriculture and urbanization, modify the dynamics of human-primate contacts, resulting in increased zoonotic risks. Although Asia shelters high primate diversity and experiences rapid expansion of human-primate contact zones, there remains little documentation regarding zoonotic surveillance in the primates of this region.

Methods

Using the PRISMA guidelines, we conducted a systematic review to compile an inventory of zoonotic pathogens detected in wild Asian primates, while highlighting the coverage of primate species, countries, and pathogen groups surveyed, as well as the diagnostic methods used across the studies. Moreover, we compared the species richness of pathogens harbored by primates across diverse types of habitats classified according to their degree of anthropization (i.e., urban vs. rural vs. forest habitats).

Results and discussion

Searches of Scopus, PubMed, and the Global Mammal Parasite Database yielded 152 articles on 39 primate species. We inventoried 183 pathogens, including 63 helminthic gastrointestinal parasites, two blood-borne parasites, 42 protozoa, 45 viruses, 30 bacteria, and one fungus. Considering each study as a sample, species accumulation curves revealed no significant differences in specific richness between habitat types for any of the pathogen groups analyzed. This is likely due to the insufficient sampling effort (i.e., a limited number of studies), which prevents drawing conclusive findings. This systematic review identified several publication biases, particularly the uneven representation of host species and pathogen groups studied, as well as a lack of use of generic diagnostic methods. Addressing these gaps necessitates a multidisciplinary strategy framed in a One Health approach, which may facilitate a broader inventory of pathogens and ultimately limit the risk of cross-species transmission at the human-primate interface. Strengthening the zoonotic surveillance in primates of this region could be realized notably through the application of more comprehensive diagnostic techniques such as broad-spectrum analyses without a priori selection.

Parasites of Free-Ranging and Captive American Primates: A Systematic Review

The diversity, spread, and evolution of parasites in non-human primates (NHPs) is a relevant issue for human public health as well as for NHPs conservation. Although previous reviews have recorded information on parasites in NHPs (Platyrrhines) in the Americas, the increasing number of recent studies has made these inventories far from complete. Here, we summarize information about parasites recently reported in Platyrrhines, attempting to build on earlier reviews and identify information gaps. A systematic literature search was conducted in PubMed, ISI Web of Science, and Latin American and Caribbean Health Sciences Literature (LILACS), and following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Ninety-three studies were included after the screening process. Records for 20 genera of NHPs, including 90 species were found. Most of the studies were conducted on captive individuals (54.1%), and morphological approaches were the most used for parasite identification. The most commonly collected biological samples were blood and stool, and Protozoa was the most frequent parasite group found. There is still scarce (if any) information on the parasites associated to several Platyrrhine species, especially for free-ranging populations. The use of molecular identification methods can provide important contributions to the field of NHPs parasitology in the near future. Finally, the identification of parasites in NHPs populations will continue to provide relevant information in the context of pervasive habitat loss and fragmentation that should influence both human public health and wildlife conservation strategies.

Schistosoma mansoni and soil transmtted helminths in olive baboons and potential zoonosis

Zoonotic pathogens are among the most important causes of ill health all over the world. The presence of these pathogens in free ranging baboons may have significant implications for humans. In Kenya, the encroachment of wildlife habitats has led to increased interaction between humans and wildlife especially non-human primates. The current study therefore aimed at investigating any possible zoonotic gastrointestinal helminths of olive baboons (Papio anubis) at the human-wildlife interface in two park borders and a ranch in Kenya, namely, Tsavo West National Park, Tana River Primate Reserve and Mutara Ranch, Laikipia, Kenya. One hundred and forty-seven baboons were used in the study. They were trapped in the wild, sampled for stool marked and then released back to the wild. Gastrointestinal (GIT) helminths identified were Strongyloides, Oesophagostomum, Enterobius spp and Trichuris Trichiura from all the three sites while Schistosoma mansoni was only detected from Tsavo baboons and with very low incidence (2.1%). The prevalence of these parasites varied among the sites but significant difference in prevalence was only noted in Strongyloides and Oesophagostomum (p < 0.05) among the three sites. This therefore implies that even with control measures instituted on the human population, baboons will always be a source of zoonotic GIT helminths especially S. mansoni even if the incidence are low. There is need to put in place measures aiming to reduce their interactions with humans and also try to control these infections in the baboons.

The role of religion in One Health. Lessons from the Hanuman langur (Semnopithecus entellus) and other human-non-human primate interactions

Being revered as deities in some religions of the world, non-human primates (NHPs) often share the same space as humans. Such coexistence and interactions with humans, especially around places of worship, have been known to cause significant changes to the behavior and diet of the NHPs in India. Moreover, the interface may also create an opportunity for zoonotic spillover, similar to the majority of newly emerging or re-emerging infections that are found to originate from animal sources. These include the SARS COV-2 virus responsible for the current COVID-19 pandemic; a catastrophic "One Health" crisis; that has highlighted the interconnections between the health of humans, animals, and the environment. Religious beliefs could potentially influence perceptions, actions, and subsequent One Health outcomes resulting from human-animal interaction, which could impact human and animal welfare. Greater insight in this area could provide a better understanding of the complex relationships between humans and NHPs; that may play an important role in mitigating conflict as well as the spillover of zoonotic disease at the human-NHP interface.

Effective Communication at Different Phases of COVID-19 Prevention: Roles, Enablers and Barriers

In an age of globalisation and hyperconnectivity, the COVID-19 pandemic has caused unprecedented and sustained impact worldwide. This article discusses issues related to (science) communication at different phases of the COVID-19 epidemic timeline. We consider the role of communication for prevention from the ecological perspective, taking into consideration that many emerging pathogens, including COVID-19, likely arise in part due to anthropogenic changes to natural environments. Communication forms part of the early response setting the scene for public buy-in of public health interventions at the start of an outbreak, as well as to maintain precautions over time. Finally, communication is a key element in increasing acceptance for new tools that require mass uptake to be effective, as seen with roll-out challenges for the COVID-19 vaccines, which faced heightened concerns of efficacy and safety while mired with rampant misinformation. Ultimately, strategies for prevention of viral epidemics such as COVID-19 must include communication strategies at the forefront to reduce the risk of the emergence of new diseases and enhance efforts to control their spread and burden. Despite key themes emerging, what constitutes effective communication strategies for different people and contexts needs to be investigated further.

Detection of zoonotic pathogens in animals performed at the University Hospital Institute Méditerranée Infection (Marseille - France)

At the University Hospital Institute Méditerranée Infection (IHU, Marseille, France), for almost thirty years, veterinarians have been carrying out epidemiological investigations, together with doctors, on animals living near human cases of zoonoses, on the one hand, and on the other hand, transverse and longitudinal epidemiological surveillance studies on animals which are reservoirs, vectors or sentinels of potentially zoonotic infections,. This article presents the methods adopted and the results obtained from these studies. They have been the subject of 76 peer-reviewed publications relating to wild animals (37 publications) and/or domestic animals (48 publications). These studies were often carried out in the field with veterinarians from the French army's health service (39 publications). They were at the origin of the detection of some thirty zoonotic pathogens in the laboratories of the IHU (64 publications) and/or other French laboratories (18 publications). Our approach is an original embodiment of the "One Health" concept.

Host Diversity and Potential Transmission Pathways of SARS-CoV-2 at the Human-Animal Interface

Emerging infectious diseases present great risks to public health. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), has become an urgent public health issue of global concern. It is speculated that the virus first emerged through a zoonotic spillover. Basic research studies have suggested that bats are likely the ancestral reservoir host. Nonetheless, the evolutionary history and host susceptibility of SARS-CoV-2 remains unclear as a multitude of animals has been proposed as potential intermediate or dead-end hosts. SARS-CoV-2 has been isolated from domestic animals, both companion and livestock, as well as in captive wildlife that were in close contact with human COVID-19 cases. Currently, domestic mink is the only known animal that is susceptible to a natural infection, develop severe illness, and can also transmit SARS-CoV-2 to other minks and humans. To improve foundational knowledge of SARS-CoV-2, we are conducting a synthesis review of its host diversity and transmission pathways. To mitigate this COVID-19 pandemic, we strongly advocate for a systems-oriented scientific approach that comprehensively evaluates the transmission of SARS-CoV-2 at the human and animal interface.

Infectious Disease Risk Across the Growing Human-Non Human Primate Interface: A Review of the Evidence

Most of the human pandemics reported to date can be classified as zoonoses. Among these, there is a long history of infectious diseases that have spread from non-human primates (NHP) to humans. For millennia, indigenous groups that depend on wildlife for their survival were exposed to the risk of NHP pathogens' transmission through animal hunting and wild meat consumption. Usually, exposure is of no consequence or is limited to mild infections. In rare situations, it can be more severe or even become a real public health concern. Since the emergence of acquired immune deficiency syndrome (AIDS), nobody can ignore that an emerging infectious diseases (EID) might spread from NHP into the human population. In large parts of Central Africa and Asia, wildlife remains the primary source of meat and income for millions of people living in rural areas. However, in the past few decades the risk of exposure to an NHP pathogen has taken on a new dimension. Unprecedented breaking down of natural barriers between NHP and humans has increased exposure to health risks for a much larger population, including people living in urban areas. There are several reasons for this: (i) due to road development and massive destruction of ecosystems for agricultural needs, wildlife and humans come into contact more frequently; (ii) due to ecological awareness, many long distance travelers are in search of wildlife discovery, with a particular fascination for African great apes; (iii) due to the attraction for ancient temples and mystical practices, others travelers visit Asian places colonized by NHP. In each case, there is a risk of pathogen transmission through a bite or another route of infection. Beside the individual risk of contracting a pathogen, there is also the possibility of starting a new pandemic. This article reviews the known cases of NHP pathogens' transmission to humans whether they are hunters, travelers, ecotourists, veterinarians, or scientists working on NHP. Although pathogen transmission is supposed to be a rare outcome, Rabies virus, Herpes B virus, Monkeypox virus, Ebola virus, or Yellow fever virus infections are of greater concern and require quick countermeasures from public health professionals.