38 



Walch (E.) & Walch-Sorgdrager (B.). A malarial Epidemic 



caused by M. sinensis [Anopheles hyrcanus]. — Meded. Burg. 

 Genecsk. Dienst Ned.- Indie, Batavia, 1921, no. 1, pp. 2-47, 1 map, 

 1 chart, 10 tables. (Also in Dutch.) 



At the end of 1919 a malaria epidemic of a mild character and 

 without fatal cases began on a coconut estate on the east coast of 

 Sumatra about three miles from the sea. Anopheles hyrcanus 

 (sinensis) was the chief carrier of both benign and malignant tertian, 

 A. ludloicji and A. [Cellia) kochi being also concerned. 



The mosquitos dissected were : A. ludloioi, 58, of which 10 

 (17-5 per cent.) were infected; .4. hyrcanus, 7,257, of which 107 

 (1 • 5 per cent.) w-ere infected ; A . kochi, 79, of which 9 (11-5 per cent.) 

 w-ere infected; A. minimus var. aconitus, 43, of which 1 (2 per cent.) 

 was infected ; and A . punctulatus, 1 , which was infected. The infection 

 of mosquitos of different ages (as shown by the number and size of 

 the ova) was investigated from January to March. Old individuals 

 predominated. Mosquitos without ova were almost free from infection 

 (1 in 318). 



.4. hyrcanus and -4. barbirosfris were abundant in drains. A few 

 A. vagus [indefinitus) were found, and one A. hyrcanus was taken 

 from salt-water quite close to the sea. When A. ludlowi appeared 

 in numbers in June 1920, its breeding-places were found near the 

 village. No breeding-places of A. kochi were found. Though the 

 larv^ae of A. barbirosfris almost equalled A. hyrcanus in numbers, 

 only 15 adults of the former were captured to about 12,000 of the latter. 



No infection of .4. hyrcanus on such an extensive scale has been 

 previous!}' observed, and no epidemic has been recorded with this 

 Anopheline as the chief carrier. Swellengrebel and Schtiffner have, 

 however, pointed out that non-dangerous carriers may become 

 important by keeping up an epidemic caused by a dangerous species, 

 or, as apparently in this case, by occurring in very large numbers. 



The cysts in A. hyrcanus contained all kinds of pigment, including 

 that characteristic of benign tertian. Its absence in A. kochi seems to 

 show that this species only carries malignant tertian. This pigment 

 was also absent in A. ludlowi. 



The general employment of quinine ga\'e good results, and drainage 

 was also undertaken. The building of buffalo sheds proved un- 

 successful. A few oiling experiments with a mixture of equal parts 

 residue and solar oil were effective. Large scale oiling was planned, 

 but not carried out owing to the decrease of malaria and mosquitos 

 in March ; the need for it became more urgent with the appearance of 

 .4. ludlowi in June. About 13,000 adult mosquitos were captured, 

 including over 100 infected individuals. 



ScHUFFXER (W.) & HvLKEiNiA (B.). Die Malaiia-Epidcmie in Naras im 

 Jahre 1918. [The Malaria Epidemic at Naras in 1918.]— Meded. 

 Burg. Geneesk. Dienst Ned.-Indie, Batavia, 1921, no. 1, pp. 48-91, 

 4 figs., 1 map, 2 charts. (.Vlso in Dutch.) 



A severe epidemic of malaria was reported in August 1918 from 

 a village of 3,600 inhabitants on the west coast of Sumatra. A tidal 

 lagoon contained the only breeding-places found of A nopheles ludlowi, 

 the carrier responsible for the outbreak. A . barbirostris and A . hyrcanus 

 [sinensis] were taken from a pool of brackish water ; like A . umbrosus. 



