Archives

selective pressure – this is when a factor in the environment causes one type of organism to develop and grow in preference to another. With HIV drug resistance, the presence of a drug exerts selective pressure for resistance to develop. …

RNA – an abbreviation for the scientific word for genetic material found in some types of viruses. It is the abbreviation for ribonucleic acid. It is very similar to DNA but is single-strand rather than the double-strand in DNA. See …

compensatory mutation – this refer to an additional mutation, usually in the context of the fitness of a virus. For example, the mutations that stop a drug form working often stop the virus from reproducing as well. Additional mutations that …

revertant mutation – this term is used in two ways. Firstly when referring to a genetic change that shows the virus is returning from a drug resistant mutation back to a wild-type genotype. This can sometimes take several stages. For …

reverse transcriptase – an enzyme unique to HIV. It is used to convert single-strand RNA into double-strand DNA. This is needed before HIV’s genetic material can be integrated in the human DNA. HIV drugs that stop this process are called …

superinfection – another term for reinfection.

reinfection – catching HIV a second time. When an HIV-positive becomes infected with second strain or type of HIV. Sometimes called superinfection.

phenotype test – a type of drug resistance that tests whether a drug is sensitive or resistance to a sample of HIV.

partially active – the HIV treatment in question will work against this virus but this is reduced compared to wild-type HIV. This is the same as partial resistance, or intermediate resistance etc.

nucleotide – the building blocks of the genetic code (DNA/RNA). Also called a base.

secondary mutation – see minor mutation.

primary mutation – see major mutation.

minor mutation – a drug resistance mutation that have a big impact on whether a drug continues to work. This used to be called a secondary mutation.

major mutation – a drug resistance mutation that have a big impact on whether a drug continues to work. This used to be called a primary mutation.

clinical cut-off (CCO) – a test result that is associated with an impact on clinical care. With resistance tests a lower CCO is the level below which a drug is still sensitive or active. This is often set at a …

Intermediate level resistance – when a drug still has some impact on HIV, but when this is reduced (compared to wild-type HIV) because there is some drug resistance.

high level resistance – when an HIV drug no longer works against the virus.

genotype test – a test that looks at how the genetic structure of a sample of HIV and whether the virus has changed with drug resistant mutations.

drug resistant mutation – a mutation or change that occurs in the HIV genome that reduces a drugs ability to work.

DNA – an abbreviation for the scientific word for genes and genetic material. It is the abbreviation for deoxyribonucleic acid. See RNA.