| Show r rn d n TV i J i u y ve M L LOn On the left 1 r e foot and leg 0 J ji of one of the i ih h heroic d dough dough- doughi h ht i i t f A boys in in the t s 8 j j c cage age into r t lf p r which several t 0 the sus- sus The mosquito known as Aed s r petted mos mos- Egypti which the recent t i 7 4 f were 4 h meats menta in the Philippines proved Is s introduced to guilty of carrying the germs of I see what ef- ef efI ef i I I f the dread d dengue or f 1 I feet the their i ir iI r I j j j t J i fever fe i b bites would 1 s h SEVEN American soldiers SEVENTY SEVEN S in the Philippine Islands have been for commended for bravery not military prowess but but but- For facing a a mosquito firing squad to be shot with the dread germs ot of dengue fever These doughboy heroes in the pink of condition voluntarily entered a specially prepared hospital ward I where lying on beds with their feet thrust in cages containing germ infected mosquitoes mosquitoes mosquitoes toes they calmly and quietly submitted to the attacks of the deadly insects seven Forty-seven of these laboratory aces became be- be became be became came casualties but recovered Through their bodies the dis- dis disease disease dis disease ease commonly known ns as fever raged Their sacrifice has resulted in medical n knowledge which will I greatly assist in the campaign against against this enemy of troops in the tropics But dengue is not solely a tropical mal mat malady ady Frequent out out- outbreaks outbreaks outbreaks breaks occurred in the South Five years ago it swept across the country from Georgia to the Panhandle at- at attacking at attacking tacking per per- persons persons sons It is the cause of incalculable economic eco eco- eco economic loss to the coun coun- country coun- coun country country 1 try Through the soldiers who voluntarily stood I ft t- t If Ji i j 1 I L R W jU 1 if Il 3 v 1 r Y NJ f ir i r W A laboratory worker taking mosquitoes from one of the cages in which they were bred especially for the task of biting the soldier volunteers and infecting many of them with dengue fever I r barrage it has been learned that dengue I fever is transmitted only by the 1 I Egypti the same mosquito that once spread the deadly yellow fever 1 a It has also been shown that the mos mos- mosquito mosquito mosquito quito must bite a person who has dengue during the first three days of the disease to to b become come infected In eleven days the mosquito then becomes capable of trans trans- transmitting transmitting transmitting the fever through its bites I For Forthe Forthe Forthe the rest of its life it retains that capacity These are some of the wounds the volunteers proudly suffered High fever accompanied by head head- headache headache headache ache excruciating pains in the eyes muscles and joints giddiness nausea sore throat and extreme tenderness of the flesh In some cases the sight was wasso wasso wasso so affected that everything seemed a abright abright abright bright metallic yellow The pains when hen severe together with the mental depres depres- depression depression sion so 50 often evident during convalescence convalescence convalescence cence induced some one to describe the disease as the sum total of human misery Not only were these volunteers sniped at from two to four tour or more times by various battalions of germ filled mosquitoes but also when they failed to take cheerfully submitted to te subcutaneous injections of infected blood for the purpose of demonstrating im- im immunity immunity im immunity I i Furthermore between two and three months after their recovery from dengue practically all the volunteers in whom experimental dengue had been produced willingly underwent subcutaneous inoculations inoculations inoculations lations of infected blood from dengue patients for the purpose of ascertaining the length of ot immunity following an attack These investigations were conducted by Lieutenant Colonel J l F Siler president president dent of the United States Army Medical Research Board assisted by Major Mil Mil- Milton Mil Milton ton W Halland Hall and Major A A Parker Hitchens Extraordinary precautions were vere taken takenA to te get the experimental ward thoroughly A screened Even the openings in the ceiling walls waIls plumbing fixtures etc were ere either cither sealed or screened The only entrance to te the ward was through a sheen screened cd vestibule that had two screened I I doors at each end These Those four doors opened outward A big electric fan was directed toward the outer door to blow away any strange mosquitoes that might try to sneak their way in Everything was painted white to facilitate the detec detection tion of mosquitoes not on the payroll The entire ward was thoroughly fumi fumi- fumigated fumigated fumigated gated before the experiments began One of the most important functions of the chief nurse and her assistants was to hunt for uninvited and fugitive mos mos- mosquitoes mos mos- mosquitoes mosquitoes During a period of nine m months only eight stra strays s 's were caught Four of th these these se escaped from biting cages However as these mosquitoes were cap captured cured two months before the occurrence of the first experimental production ot of dengue they could not be connected connected with any of the cases Most elaborate preparations were made for breeding the mosquitoes At first two kinds of mosquitoes were hays han han han- handled the died the edes and the as it was not known n whether the latter as aswell aswell well weIl as the former were dengue car car- carriers carnets car carriers nets At the peak of the work Colonel Siler had four breeding and reserve cages sixteen small smaIl breeding cages two forty forty biting cages two seventy breeding jars and sixteen breeding trays After working with several kinds ot of incubators th the type finally selected d was a mason jar for and a photo photo- photographic photographic photographic graphic developing tray for Two kinds of breeding cages were used for one for the storage of adult male and female for egg laying purposes and the other for the collection of adult mosquitoes as ns they emerged from the pupa cases The egg la laying ing cage had a glass front At the back was attached a sleeve made of netting and through this jars for egg laying and for mosquitoes were intro intro- introduced introduced and aud withdrawn and food was sup sup- supplied supplied plied The inside of the cage was painted white to make easier observation of ot the full grown captives es Some difficulty was experienced at first In finding a n netting fine enough to prevent the esc escape pe pe of mosquitoes Sev Sev- Several Sev- Sev Several Several eral infected lots were checked short and the two men Colonel Siler awl and Private Private vate Jesse F Rhodes most ost intimately in nave bave on hIm mm I i I i I I po W vf A V j y J CL l l American Soldiers Heroically let I k I h Themselves Be Infected f i With the Germs of f This Hi Hirl f DI D rl df ul I D- D Disease r in I Ilea rea Il ea U IS ease In Feeding the mosquitoes that were used in the remark remark- remarkable remarkable remarkable l I able experiments on OD the soldiers P V to t the Bite of ofa f fa a Mosquito That Transmits li It to t Hunan Human Beings ib c 11 ri frt M il J i tl Four of the soldiers in the hospital bravely submitting to the mosquito bites that may mean a long and painful illness and perhaps death contact with them became infected with dengue fever During the dengue season in co- co cooperation co cooperation operation with Major H F Hazlett commanding c the Second Battalion first Thirty first first Infantry Manila mosquito catching details were organized and mos mos- mosquitoes mosquitoes were captured daily in the bar bar- barracks barracks barracks racks The men were instructed to con con- concentrate con concentrate on blood blod bl od filled females It is not difficult to breed a few mos mos- mosquitoes mos mosquitoes from eggs but when a particular particular lar series of experiments hinge binge on the availability of several hundred female mosquitoes during a limited period four or five days and when infection of the mosquitoes with a disease depends in turn on the tho occurrence of the disease in test subjects it is necessary not only to plan well ahead but also elso to take every precaution so ISO that the breeding tech technique in use will not fail at the crucial moment What should the mosquitoes be given to eat cat They might feed it was sup sup- supposed supposed sup supposed posed on any one ofa of a number of kinds of food decaying food decaying organic matter plants or animal substances undergoing putrefaction carbohydrates bread breadcrumbs breadcrumbs breadcrumbs crumbs sugar banana etc bacteria sewage etc Food rich in protein seems to be the the favorite diet of and So at the suggestion of Dr Otto chief of the biological division bureau of science the blood serum of the horse was tried and found to fill the bill When the details of the technique had been perfected the yields ields of adults from a given number of adults vas ns uniformly Co ht e so ISO high that this food was selected for forthe forthe forthe the routine breeding work This is how the sto stock k of mosquitoes was kept up A A breeding jar n a it abo out three quarters three full of water was placed in the egg la lay lay- laying lay laying ing cage A few hours after eggs eg'S were laid the jar was removed Preferably n not t mor more than fifty an and never more than seventy-five seventy to eggs were al allowed al- al allowed allowed lowed to remain in one jar The r rate te teof of growth of the wrigglers was observed from day to da day and if later the development de began to fo o slow dow slowdown lowdown down m more more re blood serum was added The time interval between hatching and the emergence of the first adults usually ranged from eight to twelve days and adults adults continued to be produced for forthe forthe forthe the next five to ten days dayss da s 's Bringing up mosquitoes is u k job than nursing along rabbits or ele- ele elephants ele cle elephants Sometimes puny little in insects would be born at other times a nice looking flock would suddenly turn tum up their toes and pass out Occasionally the eggs would just stay eggs eg'S Bac Bac- Bacterial Bac- Bac Bacterial Bacterial contamination was the cause ot of these disasters All mosquitoes were bred from the egg and access to human beings for feeding purposes was completely con con- controlled con controlled trolled As the adults appeared in the small smaIl breeding cages they were caught daily in test tubes The reserve supplies of mosquitoes as aswell aswell well weIl as several lots of infected insects were fed on sugar and water A folded strip of glazed paper pa paper e was as placed in the tho lohmon loc lac dishes on which the insects could alight when taking food or water This re- re reduced re reduced the chances of mosquitoes losing their balance falling in the liquid and getting drowned When When females of either either species of mosquitoes were required required for experimental experimental mental use the proper proper number of clean lightly plugged test tubes were first places inside the reserve cage The op- op operator op operator then donned a rubber glove e- e ex extending tending well weIl over the lower end of the sleeve and put his hand and arm into the cage Only one female was caught in each elch test tube Immediately after rem removal val of the catch the species and sex were de- de determined determined de determined and the entire lot turned over overt overto overto t to W consulting entomologist for confirmation of species and sex The lot was I then placed in a biting cage taken to the hospital and applied to the leg of a patient with dengue In introducing and withdrawing the leg from the cage every precaution was taken to prevent the escape of mosquitoes mosquitoes mosquitoes toes When the cage was removed the tho number of ot mosquitoes in it was care care- carefully carefully fully checked and the cage returned to the laboratory After reaching the tho laboratory lightly plugged test tubes were introduced and all the females not ISh showing owing complete distention of ot the tummy with blood were removed counted ant an T for refusing to obey orders were killed The females that had done their duty were then counted and the total number numbers was verified 1 This roll call caIl of the mosquitoes was taken at every stage of the game A deserter de- de deserter de deserter might run amuck and ball ban up he whole business The method of handling the infected mosquitoes for the purpose of producing dengue in volunteers was exactly the same as that for exposure to dengue patients of newly emerged but mosquitoes for the purpose ot of transferring the virus to the insects ex- ex except ex except that all the mosquitoes were pre pre- presumably pre presumably infected and none was dis- dis dis discarded carded after the secondary biting ex- ex exA experiments ex experiments A U UThe The female bites freely through the daylight hours and if it hungry not infrequently it is observed observed biting after dusk though most of the biting its me were made between and 1130 a 11 m The female is very savage age in the natural state attacking ones one's ankles and hands and buzzing about the head She is extremely wary and hard to capture old hour mosquitoes are not as keen about human blood as the veterans of two or more days of age As a sort of appetizer it was found that a little sugar or banana made the mosquitoes tackle a mans man's foot with con con- considerably con considerably more gusto and relish An interval of not fewer than four da days s 's was allowed to intervene between biting bouts bouts The food supply but not water was taken away on the night ot of the third day to insure the insects hav hay having haying having ing good appetites for doughboys the next morning Most of us have wondered wondered what mos mos- mosquitoes mosquitoes live on when there are no human beings handy Colonel Siler has hat dis- dis discovered discovered dis discovered covered that even so highly domesticated a n mosquito as requires and probably lives largely on fruit juices In night biting experiments with withof the soldiers pitt their their legs in the ther the r cages about 8 p m A fair proportion f- f of the mosquitoes would do what was expected of ot them by 11 p m But sometimes the insects seemed very per pcr The soldiers would patiently patiently spend the whole uncomfortable night with their legs in cages while the mos mos- mosquitoes mosquitoes slept soundly on the netting Being such indifferent biters it was found necessary to use females to the lot when the idea was to get the mosquitoes to catch the dengue from a soldier There were always a few per centers who would not lay down Then when Colonel Siler thought he had his mosquito factory smoothly at full capacity the insect population commenced to dwindle mys mys- mysteriously mysteriously At reveille the roll call did not tally with that taken just before taps the night before The mosquitoes were watched It wast was t found that the experiments were being jeopardized by jumping spiders and the common red ant Ants were observed f carrying dead mosquitoes away In tracking down the habits of ot the army has hns done a piece of ot mental medical research second in im- im importance im importance only to its yellow fever work in incriminating this same mosquito r ri i I |
