M 76
# EXAMINATION OF DISINFECTANTS.
Two samples of disinfectants were examined by the Rideal Walker test during the year at the request of the Medical Officer of Health.
# ANTI-PLAGUE WORK.
Two cases of human plague were investigated at the Institute and pure cultures of B. pestis were isolated from infected glands in both cases.
Two rats were found to be infected with B. pestis, one was found in the same house as a human case and the other in a house near by.
Microscopic inspection of rats was carried out by the Medical Officers in charge of Victoria and Kowloon Mortuaries, any suspicious material being sent up to the Institute for further investigation.
Of a very large number of specimens sent up during the year B. pestis was identified in three cases only including the two cases noted above.
Local rodents examined were:-
Rattus Norvegicus.
Rattus Rattus.
Mus Musculus.
The examination and identification of fleas combed out from live rats was taken up by the Institute in August this year.
Up to the end of the year 362 fleas taken from 75 rats have been identified, and the Health District in which they were captured, noted for the purpose of a full report later.
The percentage of species identified was as follows:
Xenopsylla cheopis 94.8 Ctenocephalus 2.8 Ctenopsylla 2.4 Total 100.0The X. cheopis index per rat was 4.72; this agrees very closely with a former investigation carried out by the Medical Officer of Health when the X. cheopis was 4.82.