Research on Plague

By Danielle Kaletta

The Third Plague Pandemic lasted from 1855 to 1959. The disease was a major concern in London. The Medical Officers of Health kept up with the disease, tested for it, and more importantly expanded their medical research to learn about all aspects of the infection. This can be seen through the examination of the Medical Officer of Health reports from the mid 1800s to 1900s.

Plague outbreaks occurred around the world for over four centuries and was the driving force for the beginning of many public health programs (Slack 1). In the modern period, many resources were put into researching plague to expand knowledge on the bacterial cause, symptoms, outbreaks, and modes of transmission.

In a 1900 Medical Officer of Health Report from Hanover Square, 4 facts that determined public health actions related to plague were laid out:

  1. “Plague has an incubation period of 3 to 5 (in exceptional cases of perhaps 8 to 10) days”
  2. “Plague is wont, especially in its earlier manifestations, to assume a mild form, or even to present anomalous symptoms, tending to confound it with other and more innocent diseases”
  3. “Plague in all its forms must needs be regarded as personally infective”
  4. “Plague affects rats as well as the human subject; it may, indeed, be found causing mortality among these lower animals antecedent to its definite invasion of the population. There can be no doubt that the rat and man are, as regards plague, reciprocally infective”

Based on these facts, we know that the officers were gathering information on incubation period, symptoms, infection, and mortality for humans and the animal vectors. The officers were to gather as much information as they could while working in their individual districts. The information was later compiled together to be shared with other officers and city officials. Everyone was working together to try and stay ahead of any outbreaks.

The Medical Officers of Health, and the general public, were specifically concerned with any and all rats found in the districts. “Any dead rats were immediately sent to the Central Public Health Laboratory at Colindale for
examination for bacillus pestis, each rat being accompanied by a label on which is given precise information as to where the rat was found in order to arrive at a focus of infection should the examination prove positive” (City of London 1958). The entire population was so concerned about another possible outbreak, everyone was on the lookout for any rats or other creatures that could possibly contain the bacteria.

Essentially the same process was carried out when it came to individuals that presented with symptoms similar to those of the plague. Physicians were sent to the house of any person who was ill, but especially if there was a chance it was plague. Bacterial examination of the patient’s blood was often required to confirm the diagnosis of plague (Stepney 1900). While the test was being preformed it was required that the patient be quarantined, and was often taken to a specific government location so that isolation could be ensured. Throughout all of the districts the officers stated that “the Public Health Committee had authorized [them] to send” for “bacterial examination” (Poplar 1900). Also, it was stated that any information about the disease was to be forwarded to others. Every measure possible was taken to avoid spreading illness through the community, including in prisons. In one of these reports, an inmate had died and upon examination the cause of death was confirmed to be a bacteria similar to the one known to cause plague. After this was determined, every inmate that was in the house who was not recently re-vaccinated was immediately redone (City of Westminster 1901).

By far the biggest concern during this time was plague being brought over from other nations. Labs were constantly sent samples from incoming cargo and passenger ships to test for any chances they contained the bacteria. There was an entire doctrine of rules put in place that authorized the medical officers to seize peoples or rodents suspect of containing plague off of the ships until they could be tested and cleared (City of London 1961). Special care was taken to clear every ship, but especially so if they came from an an area such as the Mediterranean and Black Seas which were deemed “endemic plague areas” (City of London 1927).

Information from the labs, the Medical Officers in different districts, and physicians were all sent to officials who continued to use this to expand legislation to allow them to do more and more research. London City Council wrote out in great detail the procedure that must be followed if an instance of plague was suspected/found. One of the requirements was each patient had to be tested, and only those results (if negative) would allow them to continue their day to day lives. Similarly, in Clerkenwell sanitary authorities were allowed to collect materials and samples from any area experiencing a potential outbreak.

Early detection and treatment is vital when dealing with Plague. (World Health Organization). Because the Medical Officers of Health, the Sanitary Authority, and the general public worked so cooperativly and closely with labratories during this time to research this disease, even when it did appear it took only a few months to eradicate rather than decades (Shoreditch 1900).


  1. MOH Poplar 1900
  2. MOH Clerkenwell 1900
  3. MOH London County Council 1900
  4. MOH City of London 1927
  5. MOH City of Westminster 1901
  6. MOH Stepney 1900
  7. MOH Shoreditch 1900
  8. MOH Hanover Square 1900
  9. MOH City of London 1958
  10. MOH City of London 1961
  11. National Institute of Health
  12. SLACK, PAUL. “Responses to Plague in Early Modern Europe: The Implications of Public Health.” Social Research 55, no. 3 (1988): 433-53.
  13. World Health Organization