HIV如何人际传播？

HIV 如何人际传播？

HIV 只有通过某些体液传播，包括血液、精液（精液）、前列腺液（前液）、直肠液、阴道液和母乳。当这些体液与粘膜或受损的组织接触，或者通过针头或注射器直接进入血液时，HIV 才会传播。粘膜存在于直肠、阴道、阴茎和口腔内。

在美国，HIV 主要通过以下方式传播：

1. 与感染者进行肛交或阴道性交，且未使用避孕套或未采取药物预防或治疗 HIV。

2. 对于 HIV 阴性的一方，接受方肛交（底方）是最高风险的性行为，但插入方肛交（顶方）也有可能感染 HIV。

3. 无论是接受方还是插入方，都有可能通过阴道性交感染 HIV，尽管相较于肛交，阴道性交的传播风险较低。

4. 与 HIV 感染者共用针头、注射器、清洗水或其他用于准备注射毒品的设备。根据温度和其他因素，HIV 可以在使用过的针头中存活最多 42 天。

不常见的传播途径：

1. 从母亲传给孩子：在怀孕、分娩或母乳喂养期间。如果母亲感染 HIV 且没有进行治疗，传播风险较高。现在，所有孕妇都应接受 HIV 检测并尽早开始治疗，这已大大减少了婴儿出生时感染 HIV 的几率。

2. 被带有 HIV 的针头或其他锐器刺伤。这主要是医疗工作者面临的风险。

3. 极为罕见的传播途径：

   • 口交：用嘴巴接触阴茎（口交）、阴道（舌交）或肛门（肛交）。总体来说，口交传播 HIV 的风险非常小，但理论上，如果 HIV 阳性男性在口交时将精液射入伴侣口中，感染是可能的。欲了解如何降低口交传播风险，请参阅《口交与 HIV 风险》。

   • 接受含有 HIV 的血液输血、血液制品或器官/组织移植。虽然早期 HIV 感染者通过此途径传播，但现在由于对美国血液供应及捐献器官的严格检测，风险极小。

   • 食用被 HIV 感染者预先咀嚼过的食物。污染发生在护理者口腔内的感染血液与食物接触时。已知的病例仅限于婴儿。

   • 被感染 HIV 的人咬伤。已记录的几起案例都涉及严重的创伤和广泛的组织损伤，并且伴有血液存在。如果皮肤没有破裂，则没有传播的风险。

   • 破损皮肤、伤口或粘膜与 HIV 感染者的血液或污染了血液的体液接触。

   • 深吻，如果双方口腔内有溃疡或出血的牙龈，且 HIV 阳性伴侣的血液进入 HIV 阴性伴侣的血液中。HIV 不通过唾液传播。

How is HIV Transmitted Between People?

HIV is only transmitted through certain body fluids, including blood, semen (cum), pre-seminal fluid (pre-cum), rectal fluids, vaginal fluids, and breast milk, from a person who has HIV. These fluids must come into contact with a mucous membrane or damaged tissue, or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur. Mucous membranes are found inside the rectum, vagina, penis, and mouth.

In the United States, HIV is spread mainly by:

1. Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV.

2. For the HIV-negative partner, receptive anal sex (bottoming) is the highest-risk sexual behavior, but you can also get HIV from insertive anal sex (topping).

3. Either partner can get HIV through vaginal sex, though it is less risky for getting HIV than receptive anal sex.

4. Sharing needles or syringes, rinse water, or other equipment (works) used to prepare drugs for injection with someone who has HIV. HIV can live in a used needle up to 42 days depending on temperature and other factors.

Less commonly, HIV may be spread:

1. From mother to child during pregnancy, birth, or breastfeeding. Although the risk can be high if a mother is living with HIV and not taking medicine, recommendations to test all pregnant women for HIV and start HIV treatment immediately have lowered the number of babies who are born with HIV.

2. By being stuck with an HIV-contaminated needle or other sharp object. This is a risk mainly for health care workers.

3. In extremely rare cases, HIV has been transmitted by:

   • Oral sex—putting the mouth on the penis (fellatio), vagina (cunnilingus), or anus (rimming). In general, there’s little to no risk of getting HIV from oral sex. But transmission of HIV, though extremely rare, is theoretically possible if an HIV-positive man ejaculates in his partner’s mouth during oral sex. To learn more about how to lower your risk, see Oral Sex and HIV Risk.

   • Receiving blood transfusions, blood products, or organ/tissue transplants that are contaminated with HIV. This was more common in the early years of HIV, but now the risk is extremely small because of rigorous testing of the US blood supply and donated organs and tissues.

   • Eating food that has been pre-chewed by an HIV-infected person. The contamination occurs when infected blood from a caregiver’s mouth mixes with food while chewing. The only known cases are among infants.

   • Being bitten by a person with HIV. Each of the very small number of documented cases has involved severe trauma with extensive tissue damage and the presence of blood. There is no risk of transmission if the skin is not broken.

   • Contact between broken skin, wounds, or mucous membranes and HIV-infected blood or blood-contaminated body fluids.

   • Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner gets into the bloodstream of the HIV-negative partner. HIV is not spread through saliva.