C-section – Caesarean section, procedure to deliver a baby that involves making a cut through the abdominal wall to surgically remove the infant from the uterus.

cancer – disease caused by uncontrolled growth and spread of abnormal cells.

candida – fungus (yeast) infection that affects the mouth and throat, gullet, sinuses, genital organs and – rarely – the brain. Also called ‘thrush’.

carcinoma – cancer in tissues covering or lining organs of the body, such as the skin, the uterus, the lung, or the breast.

CART – combination anti-retroviral therapy.

CCR5 inhibitor – type of HIV drug (an entry inhibitor) that blocks HIV from getting into a CD4 cell. CCR5 is a co-receptor on the surface of a CD4 cell that HIV uses to attach itself to the cell. CCR5 inhibitors block that process. Maraviroc is currently the only approved CCR5 inhibitor.

Drug targets in the virus life cycle.

CD4 cells are white blood cells in your immune system. CD4 cells signal to CD8 cells to destroy a virus. CD4 cells are also used by HIV as factories to reproduce in.

CD4 count – number of CD4 cells in a cubic millimetre of blood. CD4 counts results are given as a number that can be anywhere from 0 to over 2000 (rarely).

The range for an HIV-negative person is usually quoted as 430 – 1690. This means 95% of HIV negative people have a CD 4 count between 430 and 1690, but also that a few people have normal levels above or below this. A ‘normal’ CD4 count for an HIV positive person means getting above 500. However, this is an ideal goal and many people remain very well and healthy with CD4 counts that are lower than this.

Test results can also be reported in three main formats. ie a CD4 count of 350 can be written as:

  • 350 cells/mm3 (cells per cubic millimetre); or
  • 350 cells/μL (cells per microlitre); or
  • 350 Χ 106 cells/L (per million cells per litre: i.e.: times 10 to the power of 6, cells per litre)

See: Units of measure.

Since 2015, most treatment guidelines recommend starting treatment at any CD4 count, even when this is above 500.

Once viral load becomes undetectable on HIV treatment (ART), this also stops sexual transmission to HIV negative partners.

CD4% – percentage of total lymphocytes (white blood cells) that are CD4 cells.

CD8 cell – cell (lymphocyte) in your immune system that kills cells infected with HIV.

CDC – Centre for Disease Control, part of the USA health administration.

central line – tube inserted into a deep vein to deliver medicine (Hickman line or PortaCath).

cervical smear – test to look for abnormal cells in the cervix and uterus.

ChemSex is a common term used by gay men for drug use that includes at least one of these three recreational drugs: meth, meph and G.

  • Methamphetamine (crystal/crystal meth/Tina/meth).
  • Mephedrone (meph/drone).
  • GHB/GBL* (G, Gina).

Differences between ChemSex and recreational drugs.

cholesterol – kind of lipid (blood fat).

chorioamnionitis is an inflammation of the membranes that surround the foetus (called the chorion and the amnion). Chorioamnionitis is usually caused by a bacterial infection.

chorionic villus sampling – test in which cells around an embryo are removed and examined to detect genetic abnormalities.

chronic – long-term.

chronic infection – established infection (everything after the first 6 months)

cirrhosis – severe scarring of the liver (see fibrosis) that makes it difficult for the liver to carry out its functions