10 



1897 to 1906 inclusive was six, from 190T to 1910 twenty-three. 

 The most severe epidemic of recent years occurred in 1905. 

 During- a journey made by the Medical Uliicer, throughout the 

 Territory, blood-smears were taken from as many suspected 

 sufferers as possible in order to obtain an estimate of the general 

 prevalence of the disease. The mining camp at Umbrawarra 

 Creek, 13 miles south of Pine Creek was visited, and numbers of 

 the miners found to be suffering from fever. All about the 

 camps were pools of stagnant water, often swarming with fish ; 

 others barely a square yard in area and several inches deep 

 were filled with decaying vegetable matter. These were simply 

 abounding in mosquito larvae and pupae. The dry season (May 

 to September) is considered the worst season for fever. All the 

 men in this camp were either suffering or had suffered from 

 fever, and in some cases the number of parasites found in the 

 blood was very great. Two of these men had come from New 

 Guinea where they had contracted the disease. The New Guinea 

 type is characterised by the extreme severity of the first attacks, 

 and if the sufferer does not succumb at this period he becomes 

 more or less immune to the action of the parasites. If no re- 

 infection occurs the patient lapses into the chronic stage of the 

 disease and is a constant source of danger to his neighbours. The 

 probability that malaria has been introduced in this manner from 

 New Guinea is very great, as the Umbrawarra fever i^ of the 

 same type as that in New Guinea, and mosquitos capable of 

 transmitting malaria are found in great numbers. 



Anopheles (Nyssorhynchus) annulipes is probably the distri- 

 buting agent. Numerous larvae and pupae were collected frotn 

 the water-holes and the adult insects bred out and identified. It 

 has been proved by Kinoshita, in Formosa, that this species of 

 Anopheline is capable of transmitting malaria. Preventive 

 measures suggested are : — (1) removal of the camp to a distance 

 of at least half a mile from the river; (2) regular oiling of the 

 pools; (3) compelling the miners to take quinine during the 

 fever season, about 15 grains twice weekly, and to sleep under 

 mosquito nets. 



Several other mining camps were visited and in all of them cases 

 of fever of a similar type to that of New Guinea were found. 

 Several of the miners affected had come from New Guinea. 

 Mosquitos were found in all these stations. 



The Medical Officer is of opinion that the evidence of impor- 

 tation of the fever and its subsequent distribution by the local 

 mosquito is conclusive, and that if the population increased so 

 would the malaria spread, owing to the presence of already 

 infected persons. 



The "wild " aborigines were found to be free, but those em- 

 ployed on the stations were subject to fever. The Medical Officer 

 suggests that a blood exnmination of new-comers, and action taken 

 upon it, might materially assist in keeping down the disease, and 

 that the miners and the children in the public schools should be 

 taught the history of malaria ond the general principles of the 

 means of prevention. 



