Show o o- o MALARIA-BEARING MALARIA MOSQUITOES IN UTAH From time to time in past years cases of malarial malarial malarial ma ma- fever have been reported in the state of Utah but so far as the writer is aware no species species species cies of the particular genus enus of mosquitoes now known to be responsible for the spread of the disease disease disease dis dis- ease has been reported present in the State If these mosquitoes were not present the reports of the disease could only be explained in one or the theother theother theother other of two ways First that the diagnosis of the case was not correct a mistake which might occur since detection of the organism causing the disease by examination of the blood of the patient patient patient pa pa- tient is the only absolute diagnosis Second the infection may have been contracted outside the State as is known to have been true of some cases reported Some time ago a former student of the University reported to me that a brother who had not been out of the State had had a case case said by the in charge to have have been typical malaria Whether a blood examination was made or not I do not know If this were a genuine case it had doubtless originated at Gar- Gar field When therefore I was informed by thu State Board of Health that two cases of malaria had been reported from Garfield during the past summer summer summer sum sum- mer I was naturally curious to know whether malarial malarial malarial ma ma- mosquitoes could be found there and responded responded responded re re- immediately to the suggestion that I make a trip to the Ule smelter town to look for mens Suffice it to say that while I encountered no difficulty whatever in meeting and capturing many mosquitoes and some mosquito larvae I secured secured secured se se- cured none but harmless ones Harmless so far faras faras faras as malaria is concerned but quite sufficiently bloodthirsty The mosquito season was passing and it seemed advisable to await the coming of another summer before making further investigation tion there Soon after this however an unquestioned case of malaria was reported to Dr Beatty of the State Board of Health from Provo Dr Beatty asked the reporting physician to secure some mosquitoes if possible and soon there camo came to me meas meas meas as a result four mosquito specimens all of which were of the malaria-bearing malaria genus anopheles A Continued on Page 4 MALARIA-BEARING MALARIA MOSQUITOES IN UTAH Continued from Page 3 few days later Dr Beatty himself secured a few more specimens from fromn the same locality All were m. m anopheles Owing to the lateness of the season no attempt has been made to learn further facts concerning the distribution of these thes forms but it is hoped to carry this on next sum sum- mer It is not unlikely that some of this species breeds in some of the swamps about Garfied or even in the environs of Salt Lake City Absolute diagnosis of the cases of the disease and full data upon the travels of the patient prior to showing symptoms would throw considerable light upon the subject Reports from St. St George indicate that malaria occurs there regularly though not abundantly Since it is known that Anopheles exists in Utah and that malaria may therefore be passed from one patient to another here the method of transmission becomes a matter of in in- terest It may be stated in the beginning that it was absolutely proved a dec decade de ago that that malarial fever is transferred from one patient to another by mosquitoes of the genus Anopheles and that it itis itis is not transferred in any other way The very name malaria bad air we therefore now ki kito kno know to be a misnomer bad air swamp vapors etc has nothing whatever to do with the disease The causative organism of malaria is a ami m in animal parasite which lives a portion o of it its life within the red corpuscles of the blood of the person or animal afflicted It consumes Digests the interior of the corpuscle and grows to fill it il It then divides into several parts spores which are erupted into the blood plasma from which each makes its way into another red corpuscle there to repeat the process described ed The recurrent recur rent chills associated with this fever occur at the periodic intervals when the spores are set free in the blood When a mosquito makes a meal on the blood of a malarial victim it takes some ol of these animal parasites into its own body There if the mosquito be a species of Anopheles they undergo a series of developmental changes quite different from the stages observable in the blood of the infected person Without going into the details details de do tails it may be said that eventually large numbers of a minute stage of the parasite penetrate the l I salivary glands of the infected mosquito whence they pass into the saliva In piercing the skin of ofa 3 a victim the mosquito allows some of the saliva to flow into the wound supposedly for the purpose purpose pur pose of preventing coagulation of the blood Whatever the purpose of the injection of saliva jit j 1 jit it results in the person bitten by the infected infected Anopheles receiving a direct inoculation of the they malaria organism Only in this way may malaria 1 1 be transferred from one person to another j jIt It may be added that the presence of Anopheles Anop j Anop-j j heles in a particular locality does not prove ro the the the- individual presence of malaria since only those individual i mosquitoes which have previously bitten a person suffering from malaria maaria are capable of infecting new patients Thus a locality to which a malarial malarial mala rial patient has never come may have Anopheles in abundance but yet have no malaria but the 1 once i ihas it j spread locality disease may spread in any such 1 has been introduced visible only Many details of structure serve serveto serveto serveto to a dissecting lens or microscope to enable the entomologist to of w OL les from other mosquitoes the most common two which belong t tc to the genus One or readily observable points however distinguiSh are them for the layman The species i. i e e. the sometimes said to be hump backed of or the the line head with the and beak make an angle plane a body proper and when they are at rest on a P surface or piercing the skin of a victim the theis body a and head is held parallel to the surface The w with Nith beak of an Anopheles are directly in line W bloodsucking blood blood- the axis of the body and when resting or tilted uP sucking the posterior end of the body is to d' d air direct If at a considerable angle to the surface species eS eSthe the beak into the skin The wings of the bro brown of Anopheles are more or less less less' spotted dark mostly P plain and yellowish while species are colored n nocturnal noc noc- are It is true of Anopheles also that they or at least crepuscular in habit There 1 s h houses bouse I fore persons living in securely screened t in the worst malarial districts may and have entirely entirely entirely en en- avoided infection by remaining indoors between between between be be- tween sunset and sunrise A demonstration of this kind was carried out on the famous Roman Campagna in 1900 as a part of the proof that malaria malaria malaria ma ma- laria is transferred only by night-flying night Anopheles CHARLES T. T VORHIES |