Parasitic STIs

pubic lice

What is pubic lice?

  • Adult pubic lice are 1.1–1.8 mm in length. Pubic lice typically are found attached to hair in the pubic area but sometimes are found on coarse hair elsewhere on the body (for example, eyebrows, eyelashes, beard, mustache, chest, armpits, etc.).

  • Pubic lice infestations (pthiriasis) are usually spread through sexual contact. Dogs, cats, and other pets do not play a role in the transmission of human pubic lice.


  • To prevent pubic lice infestation, avoid having sexual contact or sharing bedding or clothing with anyone who has an infestation. If you are being treated for pubic lice, all sexual partners also must be treated.

  • Avoid shaving, waxing, or removing pubic hair


Signs and symptoms of pubic lice include

  • Itching in the genital area

  • Visible nits (lice eggs) or crawling lice


How to treat pubic lice infestations: (Warning: See special instructions for treatment of lice and nits on eyebrows or eyelashes. The lice medications described in this section should not be used near the eyes.)

  1. Wash the infested area; towel dry.

  2. Carefully follow the instructions in the package or on the label. Thoroughly saturate the pubic hair and other infested areas with lice medication. Leave medication on hair for the time recommended in the instructions. After waiting the recommended time, remove the medication by following carefully the instructions on the label or in the box.

  3. Following treatment, most nits will still be attached to hair shafts. Nits may be removed with fingernails or by using a fine-toothed comb.

  4. Put on clean underwear and clothing after treatment.

  5. To kill any lice or nits remaining on clothing, towels, or bedding, machine-wash and machine-dry those items that the infested person used during the 2–3 days before treatment. Use hot water (at least 130°F) and the hot dryer cycle.

  6. Items that cannot be laundered can be dry-cleaned or stored in a sealed plastic bag for 2 weeks.

  7. All sex partners from within the previous month should be informed that they are at risk for infestation and should be treated.

  8. Persons should avoid sexual contact with their sex partner(s) until both they and their partners have been successfully treated and reevaluated to rule out persistent infestation.

  9. Repeat treatment in 9–10 days if live lice are still found.

  10. Persons with pubic lice should be evaluated for other sexually transmitted diseases (STDs).


What is trichomoniasis?

  • Trichomoniasis (or “trich”) is a very common sexually transmitted disease (STD). It is caused by infection with a protozoan parasite called Trichomonas vaginalis. Although symptoms of the disease vary, most people who have the parasite cannot tell they are infected.

  • "Trich"


  • External and internal condoms are great prevention and it is curable with antibiotics. It should be treated as soon as possible.

  • Abstinence

  • STI testing and treatment

  • Communicate with partner(s) about protection and possible risk

  • Barrier methods (condoms, dental dams, etc.)

  • Washing hands

  • Pee before and after sex

  • Avoid shaving, waxing, or removing pubic hair

  • Do not douche


  • Itching or irritation inside the penis;

  • Burning after urination or ejaculation;

  • Discharge from the penis.

  • Itching, burning, redness or soreness of the genitals;

  • Discomfort with urination;

  • A change in their vaginal discharge (i.e., thin discharge or increased volume) that can be clear, white, yellowish, or greenish with an unusual fishy smell.


  • Trichomoniasis can be treated with medication (either metronidazole or tinidazole). These pills are taken by mouth. It is safe for pregnant women to take this medication. It is not recommended to drink alcohol within 24 hours after taking this medication.

  • People who have been treated for trichomoniasis can get it again. About 1 in 5 people get infected again within 3 months after receiving treatment. To avoid getting reinfected, all sex partners should get treated with antibiotics at the same time. Wait to have sex again until everyone has been treated and any symptoms go away (usually about a week). Get checked at 3 months to make sure you have not been infected again, or sooner if your symptoms come back before then.