LENGTH OF LIFE OF ANCYLOSTOMA r1 . nnrr

To the Editor, The Indian ivikijiuau uamuc.

Dear Sir,?I shall be thankful if any of your readers, especially those who are engaged on research on the subject, will kindly enlighten me on the following points:?

(1) What is the average life of a hookworm, Ancylostoma duodenale or Necator americanus?

(2) What can happen to an untreated person who has got a very mild infection of hookworm and who is not exposed to further infection? Evidently he is not liable to automatic re-infection, as in the case of thread worm infection.?Yours, etc.,

ittaDTT , r n N. N. GHOSH, M.B., D.T.M

Teacher, Dacca Medical bchool.

199, Mitford Road, Dacca,

10th April, iyai.

[Dr. A. C. Chandler (Indian Journ. Med. Res., XIII, 625) carried out an investigation on the length of life of the hookworm. He found that 50 per cent, of jail residents lost their hookworm infection within three months, 70 per cent, within a year, and 80 per cent,

within two years. Dr. Maplestone (Indian Journ. Med. Res., XVIII,

085) by taking individual prisoners in the same jail has shown that although there is a decrease in the hook- worm egg count during part of the year there is an

increase at another time. He discovered that, although there was little chance of re-infection in the jail itself, the prisoners sometimes worked outside the jail. This, he contended, would lead to the falsification of Dr. Chandler's conclusions. He thinks that the appa- rent delay in the loss of the infection for as long as two years in Dr. Chandler's series is due to the occur- rence of re-infection.

420 THE INDIAN MEDICAL GAZETTE. [July, 1931.

The point lias not-, therefore, been settled, but Dr. Maplestone appears to be of the. opinion that the length of the life of a. hookworm is shorter than Dr. Chandler's figures suggest. There is, however, no question about self-infection;

this cannot possibly occur in the case of ancylostoma infection.?Editor, I. M. G.l