Non-thrombotic pulmonary embolism of brain, liver, or bone marrow tissues associated with traumatic injuries in free-ranging neotropical primates.

From 2016 to 2019, Southeastern Brazil faced an outbreak of yellow fever (YF) affecting both humans and New World primates (NWP). The outbreak was associated with a marked increase in traumatic lesions in NWP in the affected regions. Non-thrombotic pulmonary embolization (NTPE) can be a consequence of massive traumatic events, and it is rarely reported in human and veterinary medicine. Here, we describe NTPE of the brain, liver, and bone marrow in free-ranging NWP, highlighting the epidemiological aspects of these findings and the lesions associated with this condition, including data on traumatic injuries in wild NWP populations during the course of a recent YF outbreak. A total of 1078 NWP were necropsied from January 2017 to July 2019. Gross traumatic injuries were observed in 444 marmosets (44.3%), 10 howler monkeys (23.2%), 9 capuchins (31.0%), 1 titi-monkey (50.0%), and 1 golden lion tamarin (33.3%). NTPE was observed in 10 animals, including 9 marmosets (2.0%) and 1 howler monkey (10.0%). NTPE was identified in the lung and comprised hepatic tissue in 1 case, brain tissue in 1 case, and bone marrow tissue in 8 cases. Although uncommon, it is important to consider NTPE with pulmonary vascular occlusion during the critical care of traumatized NWP. In addition, this study highlights the importance of conservational strategies and environmental education focusing on One Health, not only to protect these free-ranging NWP populations but also to maintain the efficacy of epidemiological surveillance programs.

Pathogenesis of Wild-Type-Like Rhesus Cytomegalovirus Strains following Oral Exposure of Immune-Competent Rhesus Macaques.

Rhesus cytomegalovirus (RhCMV) infection of rhesus macaques (Macaca mulatta) is a valuable nonhuman primate model of human CMV (HCMV) persistence and pathogenesis. In vivo studies predominantly use tissue culture-adapted variants of RhCMV that contain multiple genetic mutations compared to wild-type (WT) RhCMV. In many studies, animals have been inoculated by nonnatural routes (e.g., subcutaneous, intravenous) that do not recapitulate disease progression via the normative route of mucosal exposure. Accordingly, the natural history of RhCMV would be more accurately reproduced by infecting macaques with strains of RhCMV that reflect the WT genome using natural routes of mucosal transmission. Here, we tested two WT-like RhCMV strains, UCD52 and UCD59, and demonstrated that systemic infection and frequent, high-titer viral shedding in bodily fluids occurred following oral inoculation. RhCMV disseminated to a broad range of tissues, including the central nervous system and reproductive organs. Commonly infected tissues included the thymus, spleen, lymph nodes, kidneys, bladder, and salivary glands. Histological examination revealed prominent nodular hyperplasia in spleens and variable levels of lymphoid lymphofollicular hyperplasia in lymph nodes. One of six inoculated animals had limited viral dissemination and shedding, with commensurately weak antibody responses to RhCMV antigens. These data suggest that long-term RhCMV infection parameters might be restricted by local innate factors and/or de novo host immune responses in a minority of primary infections. Together, we have established an oral RhCMV infection model that mimics natural HCMV infection. The virological and immunological parameters characterized in this study will greatly inform HCMV vaccine designs for human immunization. IMPORTANCE Human cytomegalovirus (HCMV) is globally ubiquitous with high seroprevalence rates in all communities. HCMV infections can occur vertically following mother-to-fetus transmission across the placenta and horizontally following shedding of virus in bodily fluids in HCMV-infected hosts and subsequent exposure of susceptible individuals to virus-laden fluids. Intrauterine HCMV has long been recognized as an infectious threat to fetal growth and development. Since vertical HCMV infections occur following horizontal HCMV transmission to the pregnant mother, the nonhuman primate model of HCMV pathogenesis was used to characterize the virological and immunological parameters of infection following primary mucosal exposures to rhesus cytomegalovirus.

The pigtail macaque (Macaca nemestrina) model of COVID-19 reproduces diverse clinical outcomes and reveals new and complex signatures of disease.

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 disease, has killed over five million people worldwide as of December 2021 with infections rising again due to the emergence of highly transmissible variants. Animal models that faithfully recapitulate human disease are critical for assessing SARS-CoV-2 viral and immune dynamics, for understanding mechanisms of disease, and for testing vaccines and therapeutics. Pigtail macaques (PTM, Macaca nemestrina) demonstrate a rapid and severe disease course when infected with simian immunodeficiency virus (SIV), including the development of severe cardiovascular symptoms that are pertinent to COVID-19 manifestations in humans. We thus proposed this species may likewise exhibit severe COVID-19 disease upon infection with SARS-CoV-2. Here, we extensively studied a cohort of SARS-CoV-2-infected PTM euthanized either 6- or 21-days after respiratory viral challenge. We show that PTM demonstrate largely mild-to-moderate COVID-19 disease. Pulmonary infiltrates were dominated by T cells, including CD4+ T cells that upregulate CD8 and express cytotoxic molecules, as well as virus-targeting T cells that were predominantly CD4+. We also noted increases in inflammatory and coagulation markers in blood, pulmonary pathologic lesions, and the development of neutralizing antibodies. Together, our data demonstrate that SARS-CoV-2 infection of PTM recapitulates important features of COVID-19 and reveals new immune and viral dynamics and thus may serve as a useful animal model for studying pathogenesis and testing vaccines and therapeutics.

Immune Profile of the Normal Maternal-Fetal Interface in Rhesus Macaques and Its Alteration Following Zika Virus Infection.

The maternal decidua is an immunologically complex environment that balances maintenance of immune tolerance to fetal paternal antigens with protection of the fetus against vertical transmission of maternal pathogens. To better understand host immune determinants of congenital infection at the maternal-fetal tissue interface, we performed a comparative analysis of innate and adaptive immune cell subsets in the peripheral blood and decidua of healthy rhesus macaque pregnancies across all trimesters of gestation and determined changes after Zika virus (ZIKV) infection. Using one 28-color and one 18-color polychromatic flow cytometry panel we simultaneously analyzed the frequency, phenotype, activation status and trafficking properties of αß T, γδ T, iNKT, regulatory T (Treg), NK cells, B lymphocytes, monocytes, macrophages, and dendritic cells (DC). Decidual leukocytes showed a striking enrichment of activated effector memory and tissue-resident memory CD4+ and CD8+ T lymphocytes, CD4+ Tregs, CD56+ NK cells, CD14+CD16+ monocytes, CD206+ tissue-resident macrophages, and a paucity of B lymphocytes when compared to peripheral blood. t-distributed stochastic neighbor embedding (tSNE) revealed unique populations of decidual NK, T, DC and monocyte/macrophage subsets. Principal component analysis showed distinct spatial localization of decidual and circulating leukocytes contributed by NK and CD8+ T lymphocytes, and separation of decidua based on gestational age contributed by memory CD4+ and CD8+ T lymphocytes. Decidua from 10 ZIKV-infected dams obtained 16-56 days post infection at third (n=9) or second (n=1) trimester showed a significant reduction in frequency of activated, CXCR3+, and/or Granzyme B+ memory CD4+ and CD8+ T lymphocytes and γδ T compared to normal decidua. These data suggest that ZIKV induces local immunosuppression with reduced immune recruitment and impaired cytotoxicity. Our study adds to the immune characterization of the maternal-fetal interface in a translational nonhuman primate model of congenital infection and provides novel insight in to putative mechanisms of vertical transmission.

PATHOLOGY OF SPIRURID INFECTION IN VERVET MONKEYS (CHLOROCEBUS PYGERYTHRUS) HOUSED IN A PRIMATE REHABILITATION CENTER.

Spirurids, specifically the Rictularia, Chitwoodspirura, Streptopharagus, and Protospirura genera, have been reported to parasitize all nonhuman primate taxa. Spirurid pathogenesis in nonhuman primates has not been reported frequently; however, Protospirura muricola has been associated with serious gastric pathologies, including gastric perforation. This study was a retrospective study of 38 vervet monkey (Chlorocebus pygerythrus) necropsies performed in a primate sanctuary that houses captive orphaned or injured wild-born vervet monkeys. Individuals were categorized according to their age, sex, and body condition score to investigate the relationships between these factors and parasite presence. This study identified P. muricola in 47.37% of the necropsied carcasses. Regarding individual factors associated with P. muricola infection, no significant differences between males and females were observed; however, relationships between parasite presence and poor body condition and advanced host age were observed. Furthermore, one monkey death was potentially directly related to spirurid pathogenic action, because the individual showed gastric perforation.

Biological implications and limitations of a cynomolgus monkey with naturally occurring Parkinson's disease.

We recently identified a cynomolgus monkey with naturally occurring Parkinson's disease (PD), indicating that PD may not be a uniquely human disease (Li et al, 2020). In our previous study, four lines of evidence, including typical PD clinical symptoms, pharmacological responses, pathological hallmarks, and genetic mutations, strongly supported the identification of a monkey with spontaneous PD (Figure 1). To the best of our knowledge, this is the first reported case of naturally developed PD in animals. This suggests that PD is not a disease restricted to humans, with its existence in a non-human primate providing a novel evolutionary angle for understanding PD. As a close relative to humans (Buffalo et al, 2019; Phillips et al, 2014; Yan et al, 2011), this rare case of PD in another primate species provides solid evidence that monkeys are ideal candidates for the development of a genuine "animal version of PD", with conserved etiology and pathogenesis (Li et al, 2020). Furthermore, it allows us to compare similarities and differences in PD development between species and to understand PD pathogenesis from an evolutionary point of view.

Urothelial carcinoma in the urinary bladder of a Japanese macaque (Macaca fuscata).

Tumors of urinary origin are infrequently reported in non-human primates. Urothelial carcinoma involving the urinary bladder was diagnosed in an adult female Japanese macaque that extended transmurally to the uterus and cervix. To our knowledge, this is the first report of a primary cystic urothelial carcinoma in a Japanese macaque.

Two cases of cryptococcus gattii infection in the rhesus macaque (Macaca Mulatta).

Cryptococcus gattii was diagnosed in two female indoor-housed rhesus macaques. Gross and histopathologic findings included an isolated pulmonary cryptococcoma in a non-SIV-infected macaque and disseminated disease centered on the lungs of an SIV-infected macaque. Fungal yeast were positive with special stains, and the diagnoses were confirmed with a lateral flow assay and PCR.

A cervical mass in a laboratory rhesus macaque (Macaca mulatta): Suspicion of air sacculitis.

A 13-year-old rhesus macaque presented a cervical swelling associated with sudden deterioration of its condition. This mass was surgically removed, and its histopathological examination revealed a stratified squamous epithelium. This appearance has been reported in some case of air sacculitis in others non-human primate species.

Anatomopathological lesions of infection caused by Platynosomum illiciens (Braun, 1901) in Neotropical primates kept in captivity.

This study described the hepatobiliary anatomopathological lesions associated with trematode Platynosomum illiciens parasitism in Neotropical primates kept in captivity. In the evaluated organs, we observed portal fibrosis, biliary epithelial hyperplasia, and inflammatory reaction with a predominance of lymphocytes and plasmocytes, and in some cases infiltration of eosinophils and neutrophils.

Myeloproliferative Disorder with Intraoral Lesions in an Olive Baboon (Papio anubis).

Spontaneous myeloid leukemia is rarely reported in non-human primates. We report a case of myeloproliferative disorder suggestive of acute myeloid leukemia with intraoral lesions in an olive baboon (Papio anubis). Clinical pathology, radiology, gross examination (pre-mortem and post-mortem), histopathology, and immunohistochemistry findings are provided.

Scent (Apocrine) Gland Adenocarcinoma in a Wedge-Capped Capuchin Monkey (Cebus olivaceus): Histological and Immunohistochemical Features.

In humans, apocrine gland tumours encompass a heterogeneous group of uncommon neoplasms with varied and unpredictable biological behaviour. They can be slow-growing lesions, recur after excision, produce lymph node metastasis in up to 50% of cases or lead to tumour-related death. We document a malignant scent adenocarcinoma in a wedge-capped capuchin monkey (Cebus olivaceus). Immunohistochemical labelling revealed complete absence of myoepithelial cells, a finding usually considered a hallmark of malignancy in humans; however, after a 2-year follow-up, the neoplasm had not recurred. This is the first detailed report of the pathology of a spontaneous scent (apocrine) gland adenocarcinoma in a non-human primate.

Aberrant Expression of Cell Cycle Regulator 14-3-3-σ and E-Cadherin in a Metastatic Cholangiocarcinoma in a Vervet Monkey (Chlorocebus pygerythrus).

We present a unique case of metastatic cholangiocarcinoma with concurrent abdominal cestodiasis in an African green monkey (Chlorocebus pygerythrus) that presented with respiratory insufficiency and abdominal discomfort. There were multiple white-grey masses in the liver and colonic serosa alongside intra-abdominal parasitic cysts. Histopathologically, the liver masses were composed of poorly-differentiated epithelial cells that formed densely cellular solid areas and trabeculae. The neoplastic cells were strongly immunopositive for CK7 but negative for Hep-Par1 antigen, which confirmed a diagnosis of cholangiocarcinoma. Interestingly, there was strong and diffuse neoexpression in the tumour of the cell cycle regulator 14-3-3σ, which is not constitutively expressed in normal liver. There was aberrantly strong expression of E-cadherin, a key cell-cell adhesion protein, in neoplastic cells with evidence of cytoplasmic internalization. This is the first immunohistochemical analysis of 14-3-3σ and E-cadherin in a liver neoplasm in an animal species and the use of these markers requires further investigation in animal liver neoplasms.

Clinical and pathological aspects of first report of Tunga penetrans infestation on southern brown howler monkey (Alouatta guariba clamitans) in Rio Grande do Sul, Brazil.

BACKGROUND: Tungiasis is a neglected neotropical disease caused by penetration of Tunga spp. into the skin of the host. METHODS: Two primates were rescued from nearby different indigenous villages, and the clinical, pathological, and parasitological features of tungiasis were described. Flea identification occurred through their morphometry and was confirmed with the use of a dichotomous key. RESULTS: Monkey 1 was parasitized by 23 sand fleas and, after treatment, was assigned to the animal rehabilitation center. Monkey 2 was in poor body condition and died shortly after clinical examination. At necropsy, this primate was parasitized by 26 specimens of sand fleas. CONCLUSIONS: Both animals altered their tree behavior by staying on the ground for long periods. This parasitic relationship implies the possibility of enlargement of the sand flea dispersion. Thus, this is the first record of Tunga penetrans occurrence in wild Alouatta guariba clamitans.

Pathology Associated With Streptococcus spp. Infection in Baboons (Papio spp.).

Streptococcus spp. are a source of morbidity and mortality in captive nonhuman primate populations. However, little is known about the lesions associated with naturally occurring streptococcal infections in baboons (Papio spp.). The pathology database of the Southwest National Primate Research Center was searched for all baboon autopsies from 1988 to 2018 in which Streptococcus spp. were cultured. Baboons on experimental protocol were excluded. The gross autopsy and histopathology reports were reviewed. Archived specimens were retrieved and reviewed as needed for confirmation or clarification. Fifty-six cultures were positive for Streptococcus spp. in 54 baboons with evidence of bacterial infection. Associated gross lesions included purulent exudate, fibrinous to fibrous adhesions, hemorrhage, mucosal thickening, organomegaly, and abscessation. Histologic lesions included suppurative inflammation, abscessation, necrosis, hemorrhage, fibrin accumulation, and thrombosis. Lungs and pleura (n = 31) were the most commonly infected organ followed by the central nervous system (n = 16), spleen (n = 15), soft tissues (n = 12), air sacs, liver, peritoneum, adrenal glands, heart, lymph nodes, uterus, kidneys, biliary system, bones, ears, umbilical structures, mammary glands, pancreas, placenta, and salivary glands. Infections by non-ß-hemolytic Streptococcus spp. predominated in the lungs and air sacs; the most common isolate was Streptococcus pneumoniae. Infections by ß-hemolytic Streptococcus spp. predominated in the soft tissues and reproductive tract. Naturally occurring ß-hemolytic and non-ß-hemolytic Streptococcus spp. infections cause morbidity and mortality in captive baboon populations. The lesions associated with streptococcal infection are similar to those reported in human infection. Thus, the baboon may represent an underutilized model for studying Streptococcus spp. as pathogens.

Histopathologic Patterns and Susceptibility of Neotropical Primates Naturally Infected With Yellow Fever Virus.

Yellow fever is an important zoonotic viral disease that can be fatal for both human and nonhuman primates. We evaluated histopathologic changes in free-ranging neotropical primates naturally infected with yellow fever virus (YFV) compared with uninfected cohorts. The most frequent lesions in primates infected with YFV were hepatic changes characterized by midzonal necrosis with lipidosis and mild inflammation including lymphocytes, macrophages, plasma cells, and infrequently neutrophils. Importantly, severe necrotizing hepatic lesions were often observed in Alouatta sp. (howler monkeys), whereas Callithrix sp. (common marmosets) had nearly no hepatic changes. Moderate to severe hepatic necrosis was present in 21/23 (91%) of the YFV-positive Alouatta sp. compared with 10/29 (34%) of the YFV-positive Callithrix sp. (P < .0001; odds ratio = 20). Similarly, hepatitis was more intense in Alouatta sp. compared with Callithrix sp. Furthermore, the frequency of YFV infection was significantly higher in Alouatta sp. compared with Callithrix sp. or Sapajus sp. (capuchin monkeys). Therefore, these data support the notion that Alouatta sp. is highly susceptible to infection and YFV-induced lesions, whereas Callithrix sp. is susceptible to infection but has a lower frequency of YFV-induced lesions.

Transient Lymphopenia and Interstitial Pneumonia With Endotheliitis in SARS-CoV-2-Infected Macaques.

Using a reliable primate model is critical for developing therapeutic advances to treat humans infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Here, we exposed macaques to high titers of SARS-CoV-2 via combined transmission routes. We observed acute interstitial pneumonia with endotheliitis in the lungs of all infected macaques. All macaques had a significant loss of total lymphocytes during infection, which were restored over time. These data show that SARS-CoV-2 causes a coronavirus disease 2019 (COVID-19)-like disease in macaques. This new model could investigate the interaction between SARS-CoV-2 and the immune system to test therapeutic strategies.

Remdesivir (GS-5734) Is Efficacious in Cynomolgus Macaques Infected With Marburg Virus.

Marburg virus (MARV) is a filovirus with documented human case-fatality rates of up to 90%. Here, we evaluated the therapeutic efficacy of remdesivir (GS-5734) in nonhuman primates experimentally infected with MARV. Beginning 4 or 5 days post inoculation, cynomolgus macaques were treated once daily for 12 days with vehicle, 5 mg/kg remdesivir, or a 10-mg/kg loading dose followed by 5 mg/kg remdesivir. All vehicle-control animals died, whereas 83% of animals receiving a 10-mg/kg loading dose of remdesivir survived, as did 50% of animals receiving a 5-mg/kg remdesivir regimen. Remdesivir-treated animals exhibited improved clinical scores, lower plasma viral RNA, and improved markers of kidney function, liver function, and coagulopathy versus vehicle-control animals. The small molecule remdesivir showed therapeutic efficacy in this Marburg virus disease model with treatment initiation 5 days post inoculation, supporting further assessment of remdesivir for the treatment of Marburg virus disease in humans.

DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS WITH SECONDARY DYSPHAGIA IN A BLACK-HANDED SPIDER MONKEY (ATELES GEOFFROYI).

A 32-yr-old male black-handed spider monkey (Ateles geoffroyi) with marked kyphosis and reduced spinal range of motion developed intermittent regurgitation, which was managed with an acid reducer. Diffuse idiopathic skeletal hyperostosis (DISH) was suspected in this animal due to radiographically evident ossification of the anterior longitudinal ligament. At repeat radiographic evaluation 1.5 yr later, due to weight loss and increased frequency of regurgitation, the cervical spine was deviated ventrally and appeared to be impinging on the thoracic inlet. The spider monkey was humanely euthanized due to poor prognosis, and the presumptive diagnosis of DISH was confirmed via postmortem computed tomography and necropsy. DISH has not been reported in black-handed spider monkeys, and secondary dysphagia, an uncommon but recognized consequence in humans, has not been reported in a nonhuman primate. Earlier recognition of this possibly underreported disease process may increase treatment options and effectiveness of intervention.

Dental topographic change with macrowear and dietary inference in Homunculus patagonicus.

Homunculus patagonicus is a stem platyrrhine from the late Early Miocene, high-latitude Santa Cruz Formation, Argentina. Its distribution lies farther south than any extant platyrrhine species. Prior studies on the dietary specialization of Homunculus suggest either a mixed diet of fruit and leaves or a more predominantly fruit-eating diet. To gain further insight into the diet of Homunculus, we examined how the occlusal surfaces of the first and second lower molars of Homunculus change with wear by using three homology-free dental topographic measures: Dirichlet normal energy (DNE), orientation patch count rotated (OPCR), and relief index (RFI). We compared these data with wear series of three extant platyrrhine taxa: the folivorous Alouatta, and the frugivorous Ateles and Callicebus (titi monkeys now in the genus Plecturocebus). Previous studies found Alouatta and Ateles exhibit distinctive patterns of change in occlusal morphology with macrowear, possibly related to the more folivorous diet of the former. Based on previous suggestions that Homunculus was at least partially folivorous, we predicted that changes in dental topographic metrics with wear would follow a pattern more similar to that seen in Alouatta than in Ateles or Callicebus. However, wear-induced changes in Homunculus crown sharpness (DNE) and complexity (OPCR) are more similar to the pattern observed in the frugivorous Ateles and Callicebus. Based on similar wear modalities of the lower molars between Homunculus and Callicebus, we infer that Homunculus had a primarily frugivorous diet. Leaves may have provided an alternative dietary resource to accommodate fluctuation in seasonal fruiting abundance in the high-latitude extratropical environment of late Early Miocene Patagonia.