Ancient, independent evolution and distinct molecular features of the novel human T-lymphotropic virus type 4
2009

Discovery and Analysis of Human T-Lymphotropic Virus Type 4

Sample size: 1 publication 10 minutes Evidence: high

Author Information

Author(s): William M. Switzer, Marco Salemi, Shoukat H. Qari, Hongwei Jia, Rebecca R. Gray, Aris Katzourakis, Susan J. Marriott, Kendle N. Pryor, Nathan D. Wolfe, Donald S. Burke, Thomas M. Folks, Walid Heneine

Primary Institution: Centers for Disease Control and Prevention

Hypothesis

What are the evolutionary origins and molecular features of the novel human T-lymphotropic virus type 4 (HTLV-4)?

Conclusion

HTLV-4 is an ancient virus that may have evolved alongside early humans and has distinct molecular features compared to other known HTLV types.

Supporting Evidence

  • HTLV-4 shares only 62-71% nucleotide identity with other HTLV types.
  • The most recent common ancestor of HTLV-4 and HTLV-2/STLV-2 occurred 49,800 to 378,000 years ago.
  • HTLV-4 has a prototypic genomic structure with all enzymatic, regulatory, and structural proteins preserved.
  • Phylogenetic analysis shows that HTLV-4 is a distinct monophyletic viral group.
  • HTLV-4 may be prevalent due to its ancient origin and potential for cross-species transmission.

Takeaway

Scientists found a new virus called HTLV-4 in a person from Cameroon, and it might have been around for a very long time, even before humans existed.

Methodology

The complete genome of HTLV-4 was obtained using PCR-based genome walking from uncultured peripheral blood lymphocyte DNA.

Potential Biases

Potential biases in sampling and screening for simian counterparts of HTLV-4 may affect the understanding of its origins.

Limitations

Only one human infection of HTLV-4 has been reported, limiting the understanding of its epidemiology and pathogenic potential.

Participant Demographics

The study involved a single HTLV-4-infected individual from Cameroon.

Statistical Information

P-Value

p<0.00001

Confidence Interval

49,800 to 378,000 years

Statistical Significance

p<0.00001

Digital Object Identifier (DOI)

10.1186/1742-4690-6-9

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