Cross-species transmission

Cross-species transmission (CST) is the phenomenon of transfer of viral infection from one species, usually a similar species, to another. Often seen in emerging viruses where one species transfers to another which in turn transfers to humans. Examples include HIV-AIDS, SARS, Ebola, Swine flu, rabies, and Bird flu.[1]

The exact mechanism that facilitates the transfer is unknown, however, it is believed that viruses with a rapid mutation rate are able to overcome host-specific immunological defenses. This can occur between species that have high contact rates. It can also occur between species with low contact rates but usually through an intermediary species. Bats, for example, are mammals and can directly transfer rabies to humans through bite and also through aerosolization of bat salvia and urine which are then absorbed by human mucous membranes in the nose, mouth and eyes.[2]

Similarity between species, for example, transfer between mammals, is believed to be facilitated by similar immunological defenses. Other factors include geographic area, intraspecies behaviours, and phylogenetic relatedness. Virus emergence relies on two factors: initial infection and sustained transmission.[3]

Predicting transmission between species

Studies have shown that the use of Bayesian statistical methods to reconstruct virus transmission between different host species using viral gene sequences can efficiently predict cross-species transmission.[4]

See also

References

  1. ↑ Faria NR, Suchard MA, Rambaut A, Streicker DG, Lemey P. Simultaneously reconstructing viral cross-species transmission history and identifying the underlying constraints. Philos Trans R Soc Lond B Biol Sci. 2013 Feb 4;368(1614).
  2. ↑ Gary McCracken, Ph.D.,Amy Turmelle, Ph.D., Maarten J. Vonhof, Ph.D., Ivan Kuzmin, Ph.D., Charles Rupprecht, Ph.D., and Daniel Streicker, Ph.D. Host Phylogeny Constrains Cross-Species Emergence and Establishments of Rabies Virus in bats. Science. August 2010.
  3. ↑ Parrish CR, Holmes EC, Morens DM, Park EC, Burke DS, Calisher CH, Laughlin CA, Saif LJ, Daszak P.Cross-species virus transmission and the emergence of new epidemic diseases.Microbiol Mol Biol Rev. 2008 Sep;72(3):457-70.
  4. ↑ Faria NR, Suchard MA, Rambaut A, Streicker DG, Lemey P. Simultaneously reconstructing viral cross-species transmission history and identifying the underlying constraints. Philos Trans R Soc Lond B Biol Sci. 2013 Feb 4;368(1614).

External links

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