The intradermal test using as antigen a 1 per cent saline extract of Dirofilaria immitis powder was performed in Singapore on 69 persons with eosinophilic lung, 32 with mild eosinophilia, 49 with filariasis, 75 normal Asians, and 66 normal Britishers. The test was positive in 100 per cent of the cases of eosinophilic lung, 73.5 per cent of the filariasis group, 59.4 per cent of cases of mild eosinophilia, 53.3 per cent of normal Asians, and 4.5 per cent of the Britishers. The filarial complement fixation test using a 1 per cent alcoholic extract of the same antigen gave a positive rate of 100 per cent in the eosinophilic lung group, whereas only 24.5 per cent of the filariasis patients gave a positive reaction. Skin sensitivity to D. immitis antigen persisted in the cases of eosinophilic lung even when the previously positive serologic reactions had become negative following treatment with diethylcarbamazine. Therefore, the intradermal test cannot be useful in the diagnosis of either filariasis or eosinophilic lung in Singapore. In view of the skin sensitivity to a filarial antigen demonstrated in patients suffering from eosinophilic lung, the etiologic possibility of an infection by a species of filarial worm found normally in nonhuman hosts is discussed.
SIR,-I was glad to read a letter from Dr. Copeland (Dec. 6), a pioneer in bringing medical treatment to the Muruts of North Borneo.1 I feel that something should be said about the present malaria situation there. McArthur's control measures for the vector " Anopheles leucosphyrus " (now A. balabacensis), were in fact resumed by him under the new post-war Government. Clearing the undergrowth around seepages was tried during 1949-52, and showed some reduction in vector breeding and spleen-rates.2 However, more recent surveys have shown that McArthur's experimental villages no longer show any malariometric advantage over comparison villages, despite his hopes for the relative permanence of his methods. It was decided by the GovemmentjW.H.O.jUNlcEF Malaria Project to use house spraying with residual insecticide, which had proved highly effective in Sarawak against the virtually identical A. leucosphyrus. For Dr. Copeland's information, these mosquitoes do rest on walls during the night for periods sufficiently long to make them susceptible to effective attack by residual insecticides. It has been shown during the past three years that residual insecticides produce a very great decrease in the density of the vector. On Labuan Island house-spraying alone has been successful in interrupting transmission, and when combined with antimalarial drugs it has been shown capable of controlling transmission even in the most difficult parts of the interior. The complete eradication of malaria from British North Borneo now appears to be an attainable goal.
During a period of 1 month all medical practitioners were invited to notify cases of gonorrhoea. 123 were obtained including 108 men, 10 women and 5 children. Of 25 hospital cases 23 were acute and 2 chronic; 23 were all infected by prostitutes. Intercourse took place in hotels in 17, in private houses in 6 and elsewhere in 2; introduction was made by taxi-drivers in 11, hotel staff in 3, friends in 3 and not stated 8; places of contact were-bars 16, cabaret 1, streets 2, not stated 6. The author thinks that supervision of prostitutes would help but that contact tracing would be a better long-term policy.