Giardia
Giardia is a parasite that causes the diarrheal disease giardiasis. It has a number of transmission routes and is highly infectious and can be spread by sexual contact especially in men who have sex with men.
Background
Giardia is a parasite that cases the diarrheal disease giardiasis. It is very contagious and typically contracted from swallowing Giardia germs, but can be easily picked up via touching contaminated surfaces. It can therefore be contracted sexually from sucking someone who has fucked someone with Giardia, or from ass-to-ass transmissions from fisting, fingering and fucking. It would also be possible to be spread from sharing contaminated lube. It is good fisting hygiene to use gloves and to not share lube.
It has a rapid onset and will result in chronic diarrhoea, stomach cramps, bloating and nausea within 12 to 24 hours of infection. Because of the risk of infecting others, and in terms of trying to track and manage the spread, if you have chronic diarrhoea for more than 48 hours you should contact your doctor or sexual health clinic and ask for a test. Note that the symptoms are very similar to shigella.
Because of the chronic diarrhoea it is important that you keep hydrated, drink plenty of water and use a rehydration powder like Dioralyte to replace lost salts and electrolytes. Because of stomach cramps, bloating and nausea you may find it difficult to eat, in which case eating soup or protein or meal replacement shakes may help as a temporary measure.
Because it is so easily spread, be very on top of your personal hygiene and clean the toilet after use and wash hands thoroughly, keep sinks and handwashing materials clean and use separate towels and wash them frequently.
It is typically very treatable with a course of antibiotics. You should not drink alcohol with the antibiotics for treating giardiasis. It is not a good idea to take Imodium (loperamide hydrochloride) as your body is trying to get rid of the infection and toxins. The antibiotics should make you start to feel better in 2 to 3 days, but make sure you complete the full course of tablets. If you are not sure you are fully recovered after completing the course of antibiotics, request a re-test from your sexual health clinic or doctor.
In the UK on testing positive for giardia, you will be contacted by the UK Health Security Agency via text message to track infections. They will ask you to complete a survey, you do not have to complete this.
Risks
Chronic diarrhoea can result in dehydration, which if severe can result in hospitalisation. Stay hydrated and use a rehydration powder to replace lost salts and electrolytes.
You may be unable to sleep through the night and carry out normal day to day activities with chronic diarrhoea.
Giardia is very easily spread through sexual contact, contaminated surfaces and inadequate hygiene. Hygiene is of the upmost importance, especially if living and sharing bathrooms with others.
Risk Mitigation
Check with your partners about sexual health and ensure they are feeling well and healthy while before playing.
Typically Giardia and similar infections such as shigella are picked up at clubs and events where more anonymous sexual encounters are taking place and sexual health questions may not be asked. You need to evaluate your own risk acceptance of such play along with other sexual health measures.