The third Cholera epidemic that hit the world in the mid-19th century struck the city of London hard. A doctor named John Snow created a map of Cholera cases in the city, and through it managed to conclude that the disease was transmitted through contaminated water, and to identify the contaminated well. The well was neutralized, and the spread of the plague spread in the city came to a halt. Snow’s work is considered a significant milestone in epidemiology, and since 1854 it has been clear that researching the geographical dimension of an epidemic is a necessity.

Since the beginning of the Coronavirus crisis, the Ministry of Health has been publishing the places visited by people who were later diagnosed as ill. Each of us can look at the locations, and see if they also stayed in one of these places (and if so – move into isolation immediately). As the crisis progresses, the Ministry of Health has been adding different forms of access to the information – text announcements, a map, and more recently an app. In addition to the specific locations, this information can also teach us about general trends – where people are generally staying, and since these are people who were later diagnosed as sick, also where they got infected – and hence what to watch out for. To do this, we analyzed the locations by categories.

The locations have been published daily for the last two weeks, and the data below refer to a two week period that ended March 22, 2020. As the data is updated, we will also update the interactive map.

In those two weeks, 263 of the 800 locations were in synagogues or in yeshivas. The synagogues are a regular community gathering place, and as such, they seem to have been centers of spreading the disease, especially in light of the fact that Purim was a little less than two weeks ago, and many synagogues attracted large crowds. Is the concentration in synagogues typical of Jerusalem? Not necessarily. 95 of the locations of synagogues and yeshivas were in and around Jerusalem, and a similar number (107) were in and around Tel Aviv.

Other types of locations were concentrated around Tel Aviv, including restaurants (25 of 39 locations that were in and around Tel Aviv) and supermarkets (32 of 57 locations were located in and around Tel Aviv). Also noteworthy were the 231 locations that were not classified (and defined as “other”), including community centers, kindergartens, and undefined locations. Not surprisingly, the second most common location in Israel (after synagogues) is clinics and hospitals.

The message that emerges from the map is that crowds of any kind are a source of disease spread. It is important to keep in touch, but not face to face, and especially not in groups.

Good Health to all!