617
2. The epidemic appears about 14 days after the epizootic.
3. Its height is reached about a week after the epizootic reaches its
maximum.
4. The epizootic disappears, while the epidemic continues.
5. The inter-relationship of the epizootic and epidemic during the height
of the disease.
The History of Health District No. 3 in 1902.-The epizootic was existent on the 8th April.
The epidemic did not appear until 14 days later.
During May the epidemic appears to follow the epizootic.
A rise in the epizootic during the first fortnight of May, is succeeded by a rise in the epidemic during the last two weeks of May.
During the height of the disease, a close relationship exists between the epizootic and epidemic.
This chart, generally taken, shows the same characters as in that of Districts Nos. 1 and 2.
It must be remembered that this District was very slightly affected during 1902, making the construction of curves extremely difficult, and the small number of cases renders an interpretation of the curves almost impossible. A comparison with the state of affairs found in other districts, clarifies the course of events found in 1902 in this District.
The History of Health District No. 4.-On the 8th of April, the epizootic was present. No epidemic present.
A week later, the epidemic appeared. The epizootic rose during the 4th week of April. The epidemic rose during the 1st week of May. The epizootic reached its maximum during the 4th week of May. This was followed by a sudden rise in the epidemic during the 1st week of June.
The epizootic fell greatly in numbers during the last week of June.
The epidemic disappeared during the 2nd week of July. The epizootic rose again to a height during the 1st, 2nd and 3rd weeks of July.
The epidemic reappeared for 3 weeks, namely, during the 2nd, 3rd and 4th weeks of July. Subsequently the epidemic disappeared until the end of the year. The epizootic continued with exacerbations throughout the remainder of the year.
Conclusions drawn from District No. 4.--
1. The appearance of the epidemic is a week later than the epizootic. 2. A rise in epizootic plague is followed by a rise in epidemic plague. 3. A fall in epizootic plague is followed by a fall in epidemic plague. 4. The epizootic may exist rampant without the epidemic. This would appear possible only at certain periods of the year, namely, during the last quarter.
The History of Health District No. 5. -The epizootic and epidemic were late in appearance.
Rat plague appeared in the middle of April. Human plague appeared on the first of May. The general course of the disease showed an acute exacerbation of the epizootic with a more or less rapid fall.
The epidemic increased gradually, reaching its height four weeks after the maximum of the epizootic.
At the time the epidemic was at its height, the epizootic had diminished greatly. The epidemic disappeared within a week, and was followed by a recrudes- cence of the epizootic. This increase of rat plague was not followed by a great recrudescence of human plague. Cases of human plague were present, but few in number.