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.

Occupancy of wild southern pig-tailed macaques in intact and degraded forests in Peninsular Malaysia

Deforestation is a major threat to terrestrial tropical ecosystems, particularly in Southeast Asia where human activities have dramatic consequences for the survival of many species. However, responses of species to anthropogenic impact are highly variable. In order to establish effective conservation strategies, it is critical to determine a species’ ability to persist in degraded habitats. Here, we used camera trapping data to provide the first insights into the temporal and spatial distribution of southern pig-tailed macaques (Macaca nemestrina, listed as ‘Vulnerable’ by the IUCN) across intact and degraded forest habitats in Peninsular Malaysia, with a particular focus on the effects of clear-cutting and selective logging on macaque occupancy. Specifically, we found a 10% decline in macaque site occupancy in the highly degraded Pasoh Forest Reserve from 2013 to 2017. This may be strongly linked to the macaques’ sensitivity to intensive disturbance through clear-cutting, which significantly increased the probability that M. nemestrina became locally extinct at a previously occupied site. However, we found no clear relationship between moderate disturbance, i.e., selective logging, and the macaques’ local extinction probability or site occupancy in the Pasoh Forest Reserve and Belum-Temengor Forest Complex. Further, an identical age and sex structure of macaques in selectively logged and completely undisturbed habitat types within the Belum-Temengor Forest Complex indicated that the macaques did not show increased mortality or declining birth rates when exposed to selective logging. Overall, this suggests that low to moderately disturbed forests may still constitute valuable habitats that support viable populations of M. nemestrina, and thus need to be protected against further degradation. Our results emphasize the significance of population monitoring through camera trapping for understanding the ability of threatened species to cope with anthropogenic disturbance. This can inform species management plans and facilitate the development of effective conservation measures to protect biodiversity.

A pigtailed macaque model of Kyasanur Forest disease virus and Alkhurma hemorrhagic disease virus pathogenesis

Kyasanur Forest disease virus (KFDV) and the closely related Alkhurma hemorrhagic disease virus (AHFV) are emerging flaviviruses that cause severe viral hemorrhagic fevers in humans. Increasing geographical expansion and case numbers, particularly of KFDV in southwest India, class these viruses as a public health threat. Viral pathogenesis is not well understood and additional vaccines and antivirals are needed to effectively counter the impact of these viruses. However, current animal models of KFDV pathogenesis do not accurately reproduce viral tissue tropism or clinical outcomes observed in humans. Here, we show that pigtailed macaques (Macaca nemestrina) infected with KFDV or AHFV develop viremia that peaks 2 to 4 days following inoculation. Over the course of infection, animals developed lymphocytopenia, thrombocytopenia, and elevated liver enzymes. Infected animals exhibited hallmark signs of human disease characterized by a flushed appearance, piloerection, dehydration, loss of appetite, weakness, and hemorrhagic signs including epistaxis. Virus was commonly present in the gastrointestinal tract, consistent with human disease caused by KFDV and AHFV where gastrointestinal symptoms (hemorrhage, vomiting, diarrhea) are common. Importantly, RNAseq of whole blood revealed that KFDV downregulated gene expression of key clotting factors that was not observed during AHFV infection, consistent with increased severity of KFDV disease observed in this model. This work characterizes a nonhuman primate model for KFDV and AHFV that closely resembles human disease for further utilization in understanding host immunity and development of antiviral countermeasures.

The Predicament of Macaque Conservation in Malaysia

Macaques are commonly found in Malaysia, with the current existing three species placed between endangered to least concern status under the IUCN Red List, namely the stump-tailed macaque (Macaca arctoides), pig-tailed macaque (Macaca nemestrina), and the notorious long-tailed macaque (Macaca fascicularis). The species classified under the endangered and vulnerable group are facing threats mainly from the loss of habitat. Conversely, species that are categorized as least concerned are often cited at the top of human-wildlife conflicts reports in various countries, although they too are facing pressure from habitat loss. There are different methods employed to control the fast-growing population of these species, calling for different levels of investment in terms of resources. It is of great interest to understand the disparities between these species, as they are able to adapt to environmental changes and some find ways to survive in alternative localities, including urban areas. The proximity of macaques to human dwellings raises a public health concern through the transmission of zoonotic diseases. More scientific studies are imperative in order to further understand the needs of these animals for continued survival and co-existence with humans and other animals in the ecosystem. Urgent efforts must be taken to preserve the macaque’s natural habitats while creating the public awareness on the predicament of these species. The focus should be on human-wildlife conflicts todispute the existing false impression that all macaques are on equal ground and abundance in numbers.

Species diversity, abundance, and wildlife conservation status in Batang Gadis National Park, North Sumatra, Indonesia

Rambe IF, Rambey R, Siregar S. 2021. Species diversity, abundance, and wildlife conservation status in Batang Gadis National Park, North Sumatra, Indonesia. Biodiversitas 22: 5189-5196. Indonesia is one of the countries with the highest biodiversity in the world. Furthermore, the biodiversity of floral and faunal species is still being monitored and maintained, one of which is in the forest of the National Park. Batang Gadis National Park is a habitat for various species of endemic Sumatran wildlife, most of which are endangered species in the world. Therefore, this study aimed to inventory wild animals and to calculate their abundance in the Batang Gadis National Park. The study used camera traps as recording devices that were installed on permanent and non-permanent plots based on evidential animal trajectories in the National Park Management Section Region III Resort 7 Forest of Ampung Padang Forest in 2018. In the permanent plot, 10 species were documented within nine families, namely the Felidae, Tapiridae, Cervidae, Viverridae, Ursidae, Tragulidae, Suidae, Tupaiidae, and the Cercopithecidae. The highest species abundance was Macaca nemestrina (36.17%), and the second-highest was Muntiacus muntjak Zimmermann (14.89%), and then Tapirus indicus Desmarest (10,64%). Also, the Sumatran tiger (Panthera tigris sumatrae Pocock) was in the fourth position with a value of 10.63% of species abundance. Meanwhile, the lowest abundance index value was from clouded leopard (Neofelis diardi Cuvier) with 2.12%. The abundance of species from the non-permanent plots using camera trap documented a total of 13 species with 12 families namely Felidae, Tapiridae, Cervidae, Hystricidae, Viverridae, Muridae, Phasianidae, Tragulidae, Suidae, Muscicapidae, Tupaiidae, and Cercopithecidae. The highest was documented from wild boar (Sus scrofa Linnaeus) at 42.48% and the second-highest species abundance was macaque (N. nemestrina) at 26.144%. The lowest species abundance index values were tapir (T. indicus) and Javan blue robin (Myiomela diana Lesson) with 0,33% and 0,33 %, respectively. The existence of documented wildlife species in our study affirmsed the importance of Batang Gadis National Park as a natural habitat for some key and protected species.

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 four million people worldwide as of July 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.

Pharmacokinetics and biodistribution of extracellular vesicles administered intravenously and intranasally to Macaca nemestrina

Extracellular vesicles (EVs) have great potential as novel drug carriers for the treatment of various diseases. These lipid bilayer vesicles are naturally abundant in mammalian tissues and circulation, can be loaded with therapeutic small molecule drugs, (si)RNA, proteins and CRISPR/Cas9, and may be engineered for retention by specific tissues. However, many questions remain on the optimal dosing, administration route, and pharmacokinetics of EVs. Previous studies have addressed biodistribution and pharmacokinetics in rodents, but little evidence is available from larger animals. Here, we investigated the pharmacokinetics and biodistribution of Expi293F-derived EVs labelled with a highly sensitive nanoluciferase reporter (palmGRET) in a non-human primate model (Macaca nemestrina), comparing intravenous (IV) and intranasal (IN) administration over a 125-fold dose range. We report that EVs administered IV had markedly longer circulation times in plasma than previously reported in mice, and were detectable in CSF after 30-60 minutes. Already after one minute following IV administration, we observed EV uptake by PBMCs, most notably B-cells. EVs were detected in liver and spleen within one hour of IV administration. None of the IN doses resulted in readily detectable EV levels in plasma, CSF, or organs, suggesting that IN delivery of EVs in large animals including humans may require reconsideration. Furthermore, EV circulation times strongly decreased after repeated IV administration, possibly due to immune responses and with clear implications for xenogeneic EV-based therapeutics. We hope that our findings from this baseline study in macaques will help to inform future research and therapeutic development of EVs.

MALARIA KNOWLESI PADA MANUSIA

Pendahuluan: Plasmodium knowlesi merupakan agen malaria yang mulanya hanya menginfeksi kera, yakni kera ekor panjang (Macaca fascicularis) dan kera ekor babi (Macaca nemestrina). P. knowlesi telah berkembang untuk menginfeksi secara zoonotik, yaitu ditransmisikan dari hewan kepada manusia oleh vektor nyamuk Anopheles betina. Sejak kejadian endemik malaria knowlesi pertama pada tahun 2004 di Serawak, Malaysia, jumlah kasus infeksi P. knowlesi meluas dan meningkat hingga hampir ke seluruh wilayah di Asia Tenggara, termasuk Indonesia. Peningkatan kasus infeksi P. knowlesi merupakan hasil interaksi yang kompleks antara manusia, agen, dan lingkungan. Faktor individu dan lingkungan merupakan faktor risiko malaria knowlesi. Siklus hidup P. knowlesi sangat singkat dan cenderung menginfeksi semua jenis eritrosit bersama dengan spesies Plasmodium lainnya (infeksi campuran). Morfologi dan gejala klinis P. knowlesi sangat mirip dengan spesies Plasmodium lain, membuatnya sulit didiferensiasi dan turut memengaruhi peningkatan kasus infeksi. Diagnosis malaria knowlesi dengan teknik molekuler PCR merupakan metode yang paling akurat saat ini. Pengobatan terhadap malaria knowlesi harus segera dilakukan untuk mencegah progresivitas menjadi malaria berat hingga kematian. Tujuan: Artikel ini bertujuan untuk mempelajari epidemiologi, faktor risiko, siklus hidup, morfologi, gejala klinis, diagnosis dan tatalaksana terbaru terhadap kasus malaria knowlesi, terutama di Indonesia. Metode: Penulisan artikel menggunakan metode tinjauan pustaka dari berbagai literatur mengenai malaria knowlesi. Diskusi: Pengetahuan akan epidemiologi, faktor risiko, siklus hidup, morfologi, gejala klinis, diagnosis, dan tatalaksana terhadap kasus malaria knowlesi dapat menambah informasi untuk perkembangan penelitian terhadap distribusi dan pengendalian kasus malaria knowlesi. Artikel ini diharapkan dapat membantu mempercepat target eliminasi malaria di Indonesia pada tahun 2030. Kata Kunci: Infeksi, malaria knowlesi, manusia, Plasmodium knowlesi

The occurrence of Sumatran tiger (Panthera tigris sumatrae) in an industrial plantation forest area, North Sumatra, Indonesia

Sumatran tiger lives in the remaining forests on the Sumatra island, both in conservation and production areas. There are not many tiger monitoring activities conducted in production forest. Using camera traps this occupancy survey of Sumatran tiger (Panthera tigris sumatrae) carried out in a plantation forest area of PT. Toba Pulp Lestari (PT. TPL) to obtain information and monitor tiger presence in the area. However, there were no Sumatran tigers captured by the camera traps during the occupancy activities. The existence of Sumatran tiger was proven by the finding of footprints and scrapes. Other species were photographed by the camera traps, such as marbled cat ((Pardofelis marmorata), pig-tailed monkey (Macaca nemestrina), treeshrew (Tupaia sp.), Asian palm civet (Paradoxurus hermaphroditus), lizards (Eutropis sp.), Hoogerwerf’s pheasant (Lophura hoogerwerfi), wood mouse (Apodemus sylvaticus) as well as birds. It is assumed that the Sumatran tiger didn’t cross the location of research during the camera installation period. However, there are several other reasons why Sumatran tigers weren’t captured by camera traps, such as the camera traps observation time was too short and didn’t cover a larger area, so it lessens the opportunity of encounter with Sumatran tiger.Harimau Sumatera hidup di hutan yang masih tersisa di pulau Sumatera, baik di kawasan hutan konservasi maupun hutan produksi. Kegiatan pemantauan harimau di hutan produksi belum banyak dilakukan. Dengan menggunakan camera trap, survei okupansi harimau sumatera (Panthera tigris sumatrae) ini dilakukan di areal konsesi hutan tanaman industri PT. Toba Pulp Lestari (PT. TPL) untuk mendapatkan informasi dan memantau keberadaan harimau di kawasan tersebut. Namun, tidak ada harimau sumatera yang terfoto oleh kamera trap selama kegiatan survei okupansi. Keberadaan harimau sumatera dibuktikan dengan ditemukannya jejak tapak dan cakaran. Selain itu, terdapat ppesies lain yang terfoto oleh kamera trap, seperti kucing batu ((Pardofelis marmorata), beruk (Macaca nemestrina), tupai tanah (Tupaia sp.), musang pandan (Paradoxurus hermaphroditus), kadal (Eutropis sp.), sempidan aceh (Lophura hoogerwerfi), tikus hutan (Apodemus sylvaticus) serta burung. Diasumsikan bahwa harimau sumatera tidak melintasi lokasi penelitian selama masa pemasangan kamera. Namun, terdapat beberapa alasan lain mengapa harimau sumatera tidak terfoto kamera trap, seperti waktu pengamatan kamera trap yang terlalu singkat dan tidak mencakup area yang lebih luas, sehingga memperkecil peluang perjumpaan dengan harimau sumatera.

Immunization by exposure to live virus (SIVmne/HIV-2287) during antiretroviral drug prophylaxis may reduce risk of subsequent viral challenge

Rationale/Study design A major challenge in the development of HIV vaccines is finding immunogens that elicit protection against a broad range of viral strains. Immunity to a narrow range of viral strains may protect infants of HIV-infected women or partners discordant for HIV. We hypothesized that immunization to the relevant viral variants could be achieved by exposure to infectious virus during prophylaxis with antiretroviral drugs. To explore this approach in an animal model, macaques were exposed to live virus (SIVmne or HIV-2287) during prophylaxis with parenteral tenofovir and humoral and cellular immune responses were quantified. Subsequently, experimental animals were challenged with homologous virus to evaluate protection from infection, and if infection occurred, the course of disease was compared to control animals. Experimental animals uninfected with SIVmne were challenged with heterologous HIV-2287 to assess resistance to retroviral infection. Methodology/Principal findings Juvenile female Macaca nemestrina (N = 8) were given ten weekly intravaginal exposures with either moderately (SIVmne) or highly (HIV-2287) pathogenic virus during tenofovir prophylaxis. Tenofovir protected all 8 experimental animals from infection, while all untreated control animals became infected. Specific non-neutralizing antibodies were elicited in blood and vaginal secretions of experimental animals, but no ELISPOT responses were detected. Six weeks following the cessation of tenofovir, intravaginal challenge with homologous virus infected 2/4 (50%) of the SIVmne-immunized animals and 4/4 (100%) of the HIV-2287-immunized animals. The two SIVmne-infected and 3 (75%) HIV-2287-infected had attenuated disease, suggesting partial protection. Conclusions/Significance Repeated exposure to SIVmne or HIV-2287, during antiretroviral prophylaxis that blocked infection, induced binding antibodies in the blood and mucosa, but not neutralizing antibodies or specific cellular immune responses. Studies to determine whether antibodies are similarly induced in breastfeeding infants and sexual partners discordant for HIV infection and receiving pre-exposure antiretroviral prophylaxis are warranted, including whether these antibodies appear to confer partial or complete protection from infection.