Vol. V. No. 109. 



THE AGRICULTURAL NEWS. 



203 



THE PREVENTION OF YELLOW FEVER. 



(CONCLUDED.) 



The following concludes the article on the preven- 

 tion of yellow fever commenced in the last issue of the 

 Agricultural Neirs (p. 187): — 



12. The Stegomyia mosquito attacks its victim noise- 

 lessly and persistently both during the day time and at 

 night. Therefore it is necessary: — 



(1) Always to sleep under a properly made and 



securely tucked-in mosciuito net, of a gauge of 

 18 meshes to the inch. The net should always 

 be tucked in under the mattress and not 

 hang on the floor. There should be no slit 

 in the side and no holes. Take care that the 

 arms and legs are not bitten during sleep, 

 through coming in contact with the net. 



(2) To remember that a considerable number of cases 



of infection occur through trusting in nets 

 of the wrong gauge, imperfectly secured, 

 badly made, or containing holes. 



(3) That, where possible in mosquito-infected districts, 



one living room, a portion or whole of the 

 verandah, or the whole house be screened. 

 Sleeping in the afternoon without a net is as 

 dangerous as sleeping at night without one. 



(4) That as the mosquito avoids currents of air, the 



freer the through draft of air the better. 



13. In towns liable to yellow fever all sections of the 

 community should co-operate with the sanitary authority in 

 bringing to light the first case or cases of yellow fever, in order 

 that prompt measures may be undertaken at once. 



Early notification is essential to early stamping out of 

 the disease. 



The period of incubation in man, that is, the time 

 elapsing after a person has been bitten by an infected mosquito 

 and the onset of symptoms, is approximately five days. 



l-l. A patient suffering from yellow fever is capable of 

 infecting mosquitos during the first three days of the attack. 

 If bitten by a Stegomyia during this period the mosquito 

 becomes itself infected, and after the lapse of a period of some 

 ten days is capable of transmitting the disease to a healthy 

 person. 



The power which an infected mosquito possesses of 

 transmitting yellow fever has been demonstrated to persist 

 for many weeks (a period of 154 days is recorded). The 

 bite of a single infected mosquito is sufficient to cause an 

 attack of yellow fever. During the cold season, although 

 the mosquitos may not be active and bite, they may remain 

 quiescent in some parts of the house, and upon the advent 

 of warm weather, become active, and if infected in the 

 previous year, be capable of transmitting infection and start- 

 ing a fresh epidemic. 



15. The following precautions must be adopted in case 

 of infection or in any suspicious cases : — ■ 



(1) The patient must at once be properly screened 



in order to prevent the access of mosquitos. 

 Where there is any doubt as to the true nature 

 of the fever, screen the patient until the 

 diagnosis is firmly established. 



(2) The room which the patient occupies should at 



once be screened to prevent the egress of 

 any infected mosquitos. 



(3) The other rooms in the house, outhouses, base- 



ments, and closets should be thoroughly 

 fumigated to destroy all mosquitos. 

 It would be better, howevur, to remove the patient 

 to a proper isolation hospital and thoroughly 

 to fumigate the \vhole house 



(4) All houses, outhouses, and offices in the imme- 



diate vicinity should be thoroughly fumigated. 



(5) If the epidemic is spreading, general fumigation 



of the town should at once be undertaken 

 by the sanitary authority with the co-operation 

 of the citizens. 



(6) To be eflicient, fumigation should be done by 



experts only, as it is most essential thoroughly 



to stop all apertures in the room. 

 Infected mosquitos can readily escape through very 



small chinks. 

 No matter how large the openings in the verandahs 



or rooms, they can be readily closed with paper 



by men possessing skill. 



(7) The fumigating materials used are as follows : — 



(1) Sulphur. — Allow 2 B). of sulphur to 1,000 cubic 



feet. Use two pots, place them in a pan 

 containing 1 inch of water to prevent damage 

 and set fire to the sulphur by means of spirit. 

 Duration. — Three hours. 



(2) Pi/n'thrum.—AWow 3 lb. to 1,000 cubic feet 



and divide amongst two or three pots, using 

 the same precautions as with sulphur. 

 Duration. — Three hours. 



(3) Camphor and Carbolic acid. — Equal parts of 



camphor and crystallized carbolic acid are 

 fused together into a liquid by gentle heat. 

 Vaporize 4 oz. of mixture to each 1,000 

 cubic feet ; this can be done by placing the 

 liquid in a wide shallow pan over a spirit or 

 petroleum lamp ; white fumes are given oft". 

 To avoid the mixture burning, the fumes 

 .should not come in close contact with the 

 flame of the lamp. 



Ditration. — Two hours. 

 Remember that sulphur tarnishes metal work and 

 injures pianos, sewing machines, chronometers, telephones, 

 etc. 



The camphor-carbolic mixture is one of the most agree- 

 able and effective of the various agents. 



Fumigation of Imported Plants. To guard 



against the possible introduction of diseases, there is only 

 one safeguard, and that is thorough and .systematic control 

 of all plant importations. For some time past, the various 

 administrations of the South African colonies have been 

 conferring with the object of agreeing upon uniform regula- 

 tions for this purpose, and it is hoped that, before long, this 

 will be promulgated. It may appear unnecessary to some 

 to place restraints upon the introduction of grafts and 

 stocks, but when they consider how great the risk of infection 

 is, and what enormous damage would be inflicted upon our 

 fruit industry, were further infections introduced from over- 

 sea, there can be no doubt as to the right course to follow. 

 (Agricultural Journal of the Cape of Good Hope, April 

 1906.) 



