The Zov in The Torah...
In Leviticus chapter 15 the laws of the זב – Zov - a man who experiences a discharge from his penis - are outlined. If a man experiences this discharge on two days he becomes impure (טמאי), and must undergo a process of spiritual recovery that includes isolation from others and immersion in running water. If he has a third day of penile discharge he is required to bring an offering to the Temple. (The laws differ in their application to a woman who is infected, but the basic idea is the same. To keep it simple, we'll just focus on the male Zov.)
...And in the Talmud
The rabbis of the Mishnah thought that if the discharge was due to an external factor, then the person so afflicted did not become a Zov. Here is the list of those external causes of genital discharge, as outlined in today’s daf, (Nazir 65b):
נזיר סה, ב
בשבעה דרכים בודקין את הזב עד שלא נזקק לזיבה במאכל ובמשתה במשא ובקפיצה ובחולי ובמראה ובהירהור
A Zov is examined in seven ways…about food and drink [certain foods such as cheese and wine could have caused the discharge], about carrying a load, jumping and illness [strenuous physical activity could also do so], sight and thought [he is asked whether he has been thinking about or looking at women, which could have caused his discharge]…
In modern Hebrew, zivah (זיבה) is the term for gonorrhea, a sexually transmitted disease caused by the bacterial species Neisseria gonorrhoeae. Preuss, in his famous Biblical and Talmudic Medicine has this to say about the Zov:
“It is clear forthwith that the only illness we know that can be referred to here is gonorrhea” (354).
Abraham Steinberg, in his more recent three volume Encyclopedia of Jewish Medical Ethics, also identifies the disease described in Leviticus as gonorrhea, (though he notes that some rabbis identified the discharge as being sperm, rather than pus. More on that below). If a Zov is indeed a man suffering from gonorrhea, that would explain “the laws of isolation and impurity in regard to people with flux [=discharge] as being hygienic rules to prevent the spread of the disease” (Vol II, p452).
According to the Centers for Disease Control and Prevention, there are about 330,000 new cases of gonorrhea in the US. That makes it the second most common sexually transmitted disease, with first place going to chlamydia- and the two are frequently found together. The World Health Organization estimated a global total of 106 million cases in 2008 (and that’s an increase of 21% compared to 2005). Gonorrhea is most common in women age 15-19, and infections in women are usually asymptomatic. In contrast, gonorrheal infection in men is nearly always symptomatic, with the most common symptoms being pain on urination (dysuria) and purulent penile discharge. (Think of what comes out of your nose when you get a bad cold. Now think of that coming out of another orifice.) But gonorrhea is not just a disease of the genital tract. It may involve the eyes, pharynx and anus, and if it is not treated it may (rarely) progress to disseminated disease that includes endocarditis and meningitis. In women, untreated gonorrhea can cause pelvic inflammatory disease and sterility.
While the Zov in Temple times had to remove himself society and hope for an end to the symptoms, in the era of antibiotics things are different. Gonorrhea is generally easy to treat – a single shot of ceftriaxone in the muscle and a swig of oral azithromycin and you are on the mend. The problem is that drug resistant gonorrhea is now emerging worldwide, and consequently some infections are difficult to treat.
Don't Touch That Chair...
As outlined in the Torah, the Zov imparts ritual impurity to the bed on which he lies and the chair on which he sits. Preuss wrote that “the hygienic value of these regulations… is obvious.” If the disease that is described in the Torah is indeed gonorrhea, well, then today we understand enough to say that the hygienic value of these regulations is, contra Preuss, really not that obvious at all. We now know that you cannot catch gonorrhea from sitting on a chair or lying on a bed that an infected person had touched. But in fairness, such beliefs were not uncommon even a century age. We’ve had occasion to review the theories prevalent in early twentieth century America about the transmission of gonorrhea. Back then, doctors claimed girls were susceptible to infection from gonorrhea “from everyday nonsexual objects, including their mothers’ hands, bed linens…and toilet seats.” It is hardly surprising, therefore, to read in the Torah, that the Zov contaminates all he touches. But it is not so. You need sexual or oral contact to transmit the disease, (which can also be caught by the innocent new-born baby passing through its mother's infected genital tract).
Maimonides on the Nature of the Zov
In his Mishneh Torah, Maimonides identified the Zov as suffering from a physical disease – and not a spiritual one [הלכות מחוסרי כפרה 2:1]:
The Zov that is described in the Torah, is a form of semen that results from an infection in the tubes [of the genital tract]. When the discharge of the Zov flows, it does not do forcefully like ejaculate, and there is no pleasure associated with it. Rather it flows passively like dough…
(Maimonides was following the best medicine of his time when he described the discharge as a form of semen. The word gonorrhea is from the Greek roots gone meaning seed and rhein, meaning flow.)
In an era that did not have antibiotics, removing the infected person and isolating him was really all that could be done. Today, we have alternatives: antibiotics to treat the infection, and condoms to prevent its spread. But we lack the self-reckoning that the infection might encourage. I’ve treated many, many cases of gonorrhea, and every patient encounter was centered on diagnosing and treating the infection. I do not recall any discussions about changing the behavior that allowed infection to take place in the first place. Perhaps I bear responsibility for not having had that conversation, and perhaps I should have followed the example of the biblical text. That text was mistaken in some of the details of how the disease is spread, but possibly accurate in requiring the Zov to leave his social network, and perhaps reflect on the kind of behaviors that led to his infection in the first place.