Editing Virology (section)

===Viral load assays===
{{main|Viral load}}
When an assay for measuring the infective virus particle is done (Plaque assay, Focus assay), viral titre often refers to the concentration of infectious viral particles, which is different from the total viral particles. Viral load assays usually count the number of viral genomes present rather than the number of particles and use methods similar to [[Polymerase chain reaction|PCR]].<ref name="pmid33627730">{{cite journal |vauthors=Yokota I, Hattori T, Shane PY, Konno S, Nagasaka A, Takeyabu K, Fujisawa S, Nishida M, Teshima T |title=Equivalent SARS-CoV-2 viral loads by PCR between nasopharyngeal swab and saliva in symptomatic patients |journal=Scientific Reports |volume=11 |issue=1 |pages=4500 |date=February 2021 |pmid=33627730 |pmc=7904914 |doi=10.1038/s41598-021-84059-2 |bibcode=2021NatSR..11.4500Y |url=}}</ref> Viral load tests are an important in the control of infections by HIV.<ref name="pmid31515967">{{cite journal |vauthors=Nichols BE, Girdwood SJ, Crompton T, Stewart-Isherwood L, Berrie L, Chimhamhiwa D, Moyo C, Kuehnle J, Stevens W, Rosen S |title=Monitoring viral load for the last mile: what will it cost? |journal=Journal of the International AIDS Society |volume=22 |issue=9 |pages=e25337 |date=September 2019 |pmid=31515967 |pmc=6742838 |doi=10.1002/jia2.25337 |url=}}</ref> This versatile method can be used for plant viruses.<ref name="pmid28315718">{{cite journal |vauthors=Shirima RR, Maeda DG, Kanju E, Ceasar G, Tibazarwa FI, Legg JP |title=Absolute quantification of cassava brown streak virus mRNA by real-time qPCR |journal=Journal of Virological Methods |volume=245 |issue= |pages=5–13 |date=July 2017 |pmid=28315718 |pmc=5429390 |doi=10.1016/j.jviromet.2017.03.003 |url=}}</ref><ref name="pmid32765569">{{cite journal |vauthors=Rubio L, Galipienso L, Ferriol I |title=Detection of Plant Viruses and Disease Management: Relevance of Genetic Diversity and Evolution |journal=Frontiers in Plant Science |volume=11 |issue= |pages=1092 |date=2020 |pmid=32765569 |pmc=7380168 |doi=10.3389/fpls.2020.01092 |url=|doi-access=free }}</ref>