Tazriah-Metzorah:Epidemiology

Tazriah-Metzorah: Epidemiology

Late in the parsha, the reason is given.

וְהִזַּרְתֶּ֥ם אֶת־בְּנֵי־יִשְׂרָאֵ֖ל מִטֻּמְאָתָ֑ם וְלֹ֤א יָמֻ֙תוּ֙ בְּטֻמְאָתָ֔ם בְּטַמְּאָ֥ם אֶת־מִשְׁכָּנִ֖י אֲשֶׁ֥ר בְּתוֹכָֽם׃

 

You shall put the Israelites on guard against their impurity, lest they die through their impurity by defiling My Tabernacle which is among them.

 

The preceding chapters described and discussed tzoras, the affliction of humans, cloth, and homes, the entity the King James committee interpreted as leprosy. That discussion was followed by the rules for isolation, contamination and re-entry pertaining to genital discharges.

There is a recognition of contagion, the disease can be spread by contact and by shared space. The causative agent is invisible, but often hides in the affected person or object and reappears with time.  This recurrent property is translated by the Jewish Publication Society as “malignant”

כִּֽי־צָרַ֤עַת מַמְאֶ֙רֶת֙ הִ֔וא

for it is a malignant eruption;

 

The Ramban renders the word as prickly and discusses the abhorrence of such a thing.

A digression on malignancy

In my work as a cancer doctor, the word malignant is most important. Is the tumor malignant? is a question that I am often asked. The answer usually comes from a microscopic analysis of a biopsy.  The configuration of cells, identified by the pattern formed when they are stained  with chemicals that demonstrate acidity and alkalinity, is used as the determinant. This technique, which originated in the late 19^th century, is a powerful oracle. Its predictions are as reliable as the  statistics that back them. But this analysis is not identifying the malignant property, it is a surrogate marker, a set of observations that have been correlated with outcomes.

It is the outcomes that are malignant or benign. Malignant means harmful, very harmful. In oncology, a malignant diagnosis justifies deforming and debilitating surgery; it justifies the most dangerous and unpleasant (and expensive)  medications; it justifies exposure to strange and dangerous radiation energies. Malignant, in medicine, means terrifying. It is a word that should be used more carefully, if at all. The meaning is too vague, and it is used to manipulate patients and payers. The alternative is to define the relationship between the findings and the expectations for the future in detail. These are often, appropriately horrifying, but such an approach lets a person know what they are buying for their money and suffering. Many conditions with a low ( but definite) probability of evolving into a harmful process are called malignant (e.g. carcinoma in situ). I am not sure why they are so designated, but the label generates money and dread.

The predictive power of microscopic analysis is not good.  The information from the analysis of the biopsy does not provide a clear picture of the future; it  improves the guess ( and really should be used in that Baysian  manner). Current techniques including gene sequencing, cytokine profiles, and  gene expression patterns improve the prediction…but prognosis remains an occult art.

The translation of tzoras as leprosy; and the identification of whatever set of diseases the medievals called leprosy, generated dread and isolation that was misdirected. The disease we currently identify as leprosy ( Hansen’s disease) is a bacterial infection that is quite long lasting and rarely resolves without appropriate antibiotic treatment. It is a terrible disease.  The stigma, resulting from the word and the Biblical passages is usually much worse.

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Whatever this malady, tzoras, was, the rules were intended to limit its spread and its associated  mortality, especially when mixed with the sacred. The Tabernacle needed protection from the scourge. If the Temple, the central gathering place for the Israelites, became a source for the spread of these diseases, the epidemic would be horrific. The exclusion of the infected, and potentially contagious, from the sacred is comprehensible.  The sanctum is dangerous enough without the disease.

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Covid gave us all a little taste of the isolation of the leper. It provide a little help in understanding the ritual of purification: dipping a live bird into water stained with the blood of another bird ( of the same species). The survivor was a captive and some grace limited its trial to facing the death of a brother. The stain can never be erased.