Published online by Cambridge University Press: 15 May 2009
1. One hundred and seventeen rats have been examined, and thirty-two or 27·3% were found to harbour virulent Leptospira.
2. The correlation of carrier conditions with the presence of immune bodies in the serum showed:
(a) Leptospira-positive, sero-reaction negative, four or 3·4%.
(b) Leptospira-positive, sero-reaction positive, twenty-eight or 23·8%.
(c) Leptospira-negative, sero-reaction positive, twenty-one or 17·9%.
(d) Leptospira negative, sero-reaction negative, sixty-four or 54·7%.
3. The titres of the immune bodies in their sera have been determined. A positive reaction in the lower dilutions of the serum does not necessarily indicate that the rat is a carrier of virulent Leptospira.
4. There is evidence to show that there is a greater incidence of carriers amongst fully grown animals than in the young rodents.
5. Rodents which have been killed prior to examination in the laboratory are unsuitable for the determination of the presence of Leptospira.