Contemporary Distribution, Estimated Age, and Prehistoric Migrations of Old World Monkey Retroviruses

Historic and Prehistoric Epidemics: An Overview of Sources Available for the Study of Ancient Pathogens

Since life on earth developed, parasitic microbes have thrived. Increases in host numbers, or the conquest of a new species, provide an opportunity for such a pathogen to enjoy, before host defense systems kick in, a similar upsurge in reproduction. Outbreaks, caused by "endemic" pathogens, and epidemics, caused by "novel" pathogens, have thus been creating chaos and destruction since prehistorical times. To study such (pre)historic epidemics, recent advances in the ancient DNA field, applied to both archeological and historical remains, have helped tremendously to elucidate the evolutionary trajectory of pathogens. These studies have offered new and unexpected insights into the evolution of, for instance, smallpox virus, hepatitis B virus, and the plague-causing bacterium Yersinia pestis. Furthermore, burial patterns and historical publications can help in tracking down ancient pathogens. Another source of information is our genome, where selective sweeps in immune-related genes relate to past pathogen attacks, while multiple viruses have left their genomes behind for us to study. This review will discuss the sources available to investigate (pre)historic diseases, as molecular knowledge of historic and prehistoric pathogens may help us understand the past and the present, and prepare us for future epidemics.

Identification and molecular characterization of simian endogenous retrovirus in Macaca fascicularis and Macaca nemestrina from captive breeding facilities in Bogor, Indonesia

Background and Aim:

Endogenous retroviruses (ERVs) found in all vertebrates, including non-human primates (NHPs), are known to be genetically inherited. Thus, recent studies have explored ERVs for human immunodeficiency virus vaccine development using human ERV (HERV) due to the hypervariability of exogenous retroviruses which cause conventional vaccines to be ineffective. HERV was also found to be able to induce an immune response in cancer patients. This study aimed to identify and molecularly characterize ERVs from Indonesian NHPs: Macaca fascicularis and Macaca nemestrina. Then, we described the phylogenetic relationship of these isolates with those of the simian ERVs (SERVs) characterized in other species and countries.

Materials and Methods:

First, 5 mL of whole blood samples was taken from 131 long-tailed macaques and 58 pig-tailed macaques in captive breeding facilities at Bogor, Indonesia, for DNA extraction. Next, the DNA samples were screened using the SYBR Green real-time polymerase chain reaction (PCR) technique with specific primers for env (simian retroviruses [SRV]1-5 7585U19 and SRV1-5 7695L21). Positive SERV results were those with cycle threshold (CT) values < 24 (CT < 24) and melting temperature (TM) ranges of 80°C–82°C. Then, whole-genome nucleotide sequences from two pig-tailed macaques samples detected as positive SERV were generated using a nucleic acid sequencing technique which utilized the walking primer method. Subsequently, the sequences were analyzed using bioinformatics programs, such as 4Peaks, Clustal Omega, and BLAST (NCBI). Subsequently, a phylogenetic tree was constructed using the neighbor-joining method in MEGA X.

Results:

SYBR Green real-time PCR amplification results indicated that SERV (Mn B1 and Mn B140910)-positive samples had CT values of 22.37–22.54 and TM of 82°C. Moreover, whole-genome sequences resulted in 7991 nucleotide sequences, comprising long terminal repeat, gag, pro, pol, and env genes identical between the sequenced samples. Furthermore, the phylogenetic tree results indicated that both samples from M. nemestrina had 99%–100% nucleotide identities to the Mn 92227 sample identified at the National Primate Center University of Washington (NaPRC UW) which was imported from Indonesia in 1998, confirmed as a novel SERV strain. The phylogenetic tree results also indicated that although SERV whole-genome nucleotide and env amino acid sequences were clustered with SRV-2 (identity values of 82% and 79%, respectively), they had a 99%–100% nucleotide identity to Mn 92227. Meanwhile, the gag, pro, and pol amino acids were clustered with SRV-1, SRV-3, SRV-4, SRV-5, SRV-8, and SERV/1997, with 82% and 88% identity values.

Conclusion:

Based on the SYBR Green real-time PCR profiles generated, similarities with Mn 92227 were observed. Subsequent phylogenetic analysis confirmed that both samples (Mn B1 and Mn B140919) from pig-tailed macaques in the country of origin were novel SERV strains at NaPRC UW. Therefore, it could be used in biomedical research on ERVs.

Analysis of Simian Endogenous Retrovirus (SERV) Full-Length Proviruses in Old World Monkey Genomes

Simian endogenous retrovirus, SERV, is a successful germ line invader restricted to Old World monkey (OWM) species. (1) Background: The availability of high-quality primate genomes warrants a study of the characteristics, evolution, and distribution of SERV proviruses. (2) Methods: Cercopithecinae OWM genomes from public databases were queried for the presence of full-length SERV proviruses. A dataset of 81 Cer-SERV genomes was generated and analyzed. (3) Results: Full-length Cer-SERV proviruses were mainly found in terrestrial OWM, and less so in arboreal, forest- dwelling monkeys. Phylogenetic analysis confirmed the existence of two genotypes, Cer-SERV-1 and Cer-SERV-2, with Cer-SERV-1 showing evidence of recent germ-line expansions. Long Terminal Repeat (LTR) variation indicated that most proviruses were of a similar age and were estimated to be between <0.3 and 10 million years old. Integrations shared between species were relatively rare. Sequence analysis further showed extensive CpG methylation-associated mutations, variable Primer Binding Site (PBS) use with Cer-SERV-1 using PBSlys3 and Cer-SERV-2 using PBSlys1,2, and the recent gain of LTR motifs for transcription factors active during embryogenesis in Cer-SERV-1. (4) Conclusions: sequence analysis of 81 SERV proviruses from Cercopithecinae OWM genomes provides evidence for the adaptation of this retrovirus to germ line reproduction.

Transmission of infectious viruses in the natural setting at human-animal interface

Most viral pathogens causing epidemics and pandemics are zoonotic, emerging from wildlife reservoirs like SARS CoV2 causing the global Covid-19 pandemic, although animal origin of this virus remains a mystery. Cross-species transmission of pathogens from animals to humans is known as zoonosis. However, pathogens are also transmitted from humans to animals in regions where there is a close interaction between animals and humans by 'reverse transmission' (anthroponosis). Molecular evidence for the transmission of two zoonotic RNA viruses at the human-monkey interface in Rajasthan forests is presented here: a) the apathogenic Simian Foamy Viruses (SFV), and b): Influenza A viruses (IAV)-like virus, etiologic agent for human flu infecting wild Indian rhesus monkeys inhabiting Rajasthan forests. The data provide critical information on ecology and evolution of viruses of Public Health relevance. During replication, viral genomes mutate along the transmission route to adapt to the new hosts, generating new variants that are likely to have properties different from the founder viruses. Wild Indian monkeys are under-sampled for monitoring infectious diseases mainly because of the difficulties with sample collection. Monkeys are perceived as religious icons by the Hindus in India. It is extremely difficult to obtain permission from the Forest and Wildlife Department government authorities to collect wild simian blood samples for surveillance of infectious diseases caused by viral pathogens. Reducing animal-human contact and affordable vaccination are two relevant anti-viral strategies to counteract the spread of infectious zoonotic pathogens. Genbank Accession numbers: Indian SFVmac: ADN94420, IAV like virus: MZ298601.