The strange case of “sexually transmitted diseases” in China
Ideally, as one would typically assume, if a disease (or infection, if you prefer a less stigmatized description) is transmitted through sexual intercourse, we would call it a sexually transmitted disease (STD). However, no virus or bacteria recognizes its host vector from the onset. They simply evolve to adapt to a more favorable vector condition relative to others. All STDs can be transmitted through non-sexual means for this simple reason. Labeling it an STD is just a combination of: 1) the majority of infections are found to be transmitted through sexual contact, usually recorded in clinical settings by self-report or from a subpopulation that officials and doctors believe to be very sexually active; 2) the popular conviction that sexual vices are to blame for the epidemic of the said disease, so labeling it would help warn others and reduce transmission to a certain level.
But you simply don’t have any virus that only selects human sexual organs and secretions to survive in. Most pathogens find human blood and secretions a favorable environment, and they live in their host’s blood and body fluids, waiting to be transported to another host’s blood and fluids. Such an opportunity occurs when blood or fluid, or both, change hands with another human. Sexual activity would be one occasion for such an opportunity to happen, but so do many other things that happen independently of sex or during sex. If anal intercourse without proper lubrication causes tearing damage to the cell wall of one’s rectum, blood will mix with sperm, which is a body fluid that contains a certain virus, and transmission of a disease happens through the blood and fluid between two persons. In this case, to what extent shall we call it “sexual” rather than a blood infusion transmission?
Now look further. Some sexual activities during BDSM “rituals” involve minor tearing, bruising, and even cutting of one’s skin and other body parts. Just for the sake of supposition: if one’s favorite S&M foreplay ritual causes some bleeding in both partners, and they only engage in sexual intercourse after a prolonged period of foreplay and teasing, then a virus has been transmitted purely through the blood during the foreplay phase, and one partner ends up getting an infection after the episode from the other partner, shall we call this sexually transmitted or blood transmitted? If an even stranger ritual of intimacy requires cutting and exchanging blood, not very different from ancient people drinking from a cup with another person’s blood for an oath of alliance or brotherhood, and insertive sexual intercourse doesn’t even happen beyond this ritual, do you still call the transmission caused by exchanging blood during this ritual sexually transmitted?
Physicians usually do not know exactly what happened during an episode where an infection supposedly transpired. Patients are asked about their sexual orientation, injection drug use history, sexual history, partner relationships, and so on. Their partners and families are tested too. If an HIV patient is a homosexual male, doesn’t use injection drugs, and didn’t get a blood transfusion before the episode, then the recorded patient interview and medical history will be passed to administrators or directly determined by the physician for the cause of HIV: here it would most probably be classified as homosexual sexual activity. Administrators at CDCs would certainly not know what exactly happened when an infection transpired if the physicians didn’t know. But causes are published and released to the public, relevant directives for funding allocation will consult the cause data, and public health campaigns are made to target populations based on the cause data.
When two homosexual partners fought on the battlefield and one got infected with HIV by helping with his partner’s bullet wound, do we ridiculously call that a sexually transmitted infection? Yes, it was a medical accident, but it wasn’t in a clinic; yes, it was blood transfusion, but one wasn’t receiving blood. Where does our administrator fill in the sorry blank that only has four categories: mother-child, blood transfusion or medical accident, drug injection, sexual intercourse? After scrutinizing all the risk factors, it seems only sexual intercourse is left, and voilà, a new case of homosexually transmitted HIV.
In terms of probability at the population level, when various risk factors such as sexual orientation and medical history are considered altogether, we, of course, have some confidence level to determine which risk factor was most likely the cause of an infection. I am not arguing with low-probability exceptions to overturn the regular pattern that at the population level, male homosexuals with HIV but without blood transfusion and drug use history had likely acquired HIV through sexual intercourse. I am, however, arguing with realistic daily examples to show that at the microbe level, a pathogen can transmit through many possible non-sexual vectors regardless of whether sexual intercourse took place.
I find it strange when people in China often attribute the higher prevalence of HIV in southwestern China to the local liberal sex culture (e.g. Chengdu being the gay capital, Busurian girls being permissive, prostitution not too stigmatized, etc). This is an example of ecological fallacy and attribution fallacy. When you see a map of HIV distribution at the provincial level and then claim that places with higher prevalence of HIV are also sexually promiscuous or, in a more politically correct sense, sexually progressive, you are making an incorrect assumption.
The map I created from 2020 province-level health statistics of China shows that all STDs do not have a similar distribution pattern at all. While HIV is concentrated in the southwest, the more prevalent STD gonorrhea is common in the southern coastal zone where the economy is doing better. Syphilis is more widespread but has higher prevalence in the southern coastline and the northwest. I included Hepatitis B here even though it’s not commonly labeled an STD because I want to show how we don’t classify Hep B as an STD even though it can be sexually transmitted too. Interestingly enough, Hep B has a very similar pattern to syphilis. Then why is it not a STD when about 38% of Hep B were found sexually acquired in the US (Roberts et al, 2021) and 35% in China?
I don’t think you can say all four STDs are caused by more frequent, permissive, or commercial sexual behaviors. I even doubt their distributions are caused by province-level sexual activities in any shape, form, or manner. According to the sexual liberal hypothesis, if HIV is caused by promiscuous sexual activities among certain populations, then what explains gonorrhea and syphilis, whose per-act infection probability by sex is much higher than HIV, not occurring as frequently in the areas where HIV is concentrated? Conversely, since gonorrhea infection rates are very high on the southeast coast of China and we assume gonorrhea is mostly sexually transmitted, why haven’t the responsible sexual activities converted into a high HIV infection rate?
I compared the distributions in China with a cursorily made map of STD distribution in the US. You would see at a glance that the regional pattern of STD distribution in the US is more consistent. Where HIV prevalence is higher, the same places have higher syphilis and gonorrhea prevalence. The South, California, Nevada, and New York tend to have high STD rates of all types. Even Hepatitis B is more common in the South and Nevada. While you can’t generalize what was behind the infection rate, it’s safer to assume the underlying causes of region-level STD infection are similar for different types of STDs here in the States. Still, you can’t say for sure that sexual activity was the primary cause. Poverty, injection drug use, health care resources, etc., these variables are highly correlated and tend to vary at a similar pace across states.
But not so much can be concluded about the STD prevalence in China. One thing I’m suspecting is that the primary cause of one STD is NOT the primary cause of another STD in China. But sex is not one of the primary causes here — at least for HIV, and the liberal sexual hypothesis is very likely not true. While it’s true that, for STD with very low prevalence like HIV, a small group of a particular community could be responsible for most of the cases and vastly elevate the relative infection prevalence of their entire region, the inconsistent distributive patterns of the more prevalent STDs — syphilis and gonorrhea — still make me curious what could be causing the irregularities at province-level. Blood transfusion infection and medical accidents are not rare in China and remain unreported. Could that be? One can only speculate. Or, take the Durkheimian anti-reductionist approach and simply avoid explaining region-level phenomena with the imagination of what could happen between affected individuals.
