CHAPTER VI. INFECTIOUS DISEASES AND THEIR (Part 1)

CHAPTER VI. INFECTIOUS DISEASES AND THEIR PREVENTION. I. General Considerations: The Infectious Diseases — Classification — Stages — Morbific Agents — Portals of. Entry — Modes, Vehicles and Agents of Transmission. II. Principles and Practice of Prevention: Mortality — Progress in Prevention — Methods of Prophylaxis — Individual Immunity, etc. — Disinfection — Social Measures of Prophjdaxis. III. The Role and Functions of the Nurse in Prevention of Infectious Diseases: Public Health Nursing — District Nurses — Nursing in Tuberculosis — Measles — Scarlet Fever — Diphtheria — Pneu- monia— Typhoid — Poliomyelitis — Erysipelas. GENERAL CONSIDERATIONS. Diseases are divided into two principal groups, constitutional and environmental. Constitutional diseases are such as are due to organic and structural defects in the body organism, such as diseases of circulation, digestion, metabolism, etc. Environmental diseases are due to extrinsic factors, external interference and to the invasion of the body by morbific agents. The prevention of constitutional diseases is within the scope of personal hj^giene. The prevention of environmental disease is within the functions of public hygiene and sanitation, because the etiological en^•ironmental factors are those which usually act in large groups and upon large masses of f/A'.vA'AM/. coxsi i)i:i:.\rn>.\s \)\ j)('t>|)lt', ami ;il>ii licciiiix' llic prcx ciit Kui ol ^iidi tli>- cMscs is only ])(»>il)I(" witli the lidp iiikI cDtiixTMt ioii of the w liolf coiiimiiiiit)-. riif iiio>t iiiipoiiaiit cinironiiiciital diseases arc those which aiT \ai-ioii>ly tcniici! infections, com- imiincal)lc, contauioiis, pestilential, parasitic, /yiiiotic, etc., I)ut which are all includeil nnder the one term coiniinniicahle diseases. The followiiii,'- is a list of coniinunicahle and infectious (iiseases, alplialx'tically arranu'ed: Actinomycosis. Anthrax. ( 'hieken-[)ox. ( holera. I )oni,nie. Diphtheria. Dysentery: (a) Ainel)ic. (h) Hacillary. I'avns. (lermaii measles. (Handers. (lonococcus infection. I lookworm disease. Lepro.sy. Malaria. Measles. Meningitis: (o) K|)ideTnic eerehrospinal. (h) 'J'nl)erculons. Mnmjis. ( )plithalmia ii(;onatorum. 192 IXFECTIOUS DISEASES AND PREVENTION Paratyphoid fever. Plague. Pneumonia (acute). Poliomyelitis (acute infectious). Rabies. Rocky Mountain spotted or tick fever. Scarlet fever. Septic sore throat. Smallpox. Syphilis. Tetanus. Trachoma. Trichinosis. Tuberculosis (all forms, the organ or part affected in each case to be specified). Typhoid fe'er. Typhus fever. AVhooping-cough . Yellow ieyev. The majority of the communicable diseases have been found to be caused by the entrance into the body of certain microorganisms of animal and vegetable origin. These microorganisms live, develop, reproduce, in- crease and multiply within the body or the body organs and either directly destroy vital tissues and important organs or evolve certain toxic products which interfere with proper body metabolism or cause pathological changes constituting the specific symptoms and signs of the various diseases. The chief characteristic of most of these diseases is that they are communicated and transmitted from one person to another person either directly or indirectly, GESERAL COXSIDf-Jh'ATlOXS W)'.] hy coiitjict (»r t lii"(iiii;li llic inciliuiii of ccrtaiii ohjccts, ill one \;iy (tr MiKttlicr, or in scxcral ways coiiiltiiKMl. Tin* (•(miiimiiicahlr discasos arc classified acc(»nliii<; to the shape, cliaractrristics, aiul cliaracter of the morbific ajji'iits wliidi cause tliciii, or according to proniiiieut syinptoins or ,i,n'oups of s'inptonis, skin lesions, etc., which each or certain gronps represent, or according to the mode, vehicle and agent of trans- mission. Infectious diseases are characterized by having cer- t4iin stages, such as exposure, infection, invasion, incubation, acme, decline, etc. The stiige of exposure is the time during which the person is exposed to the presence of morbific agents. Tiie ix'riod of infection is tlie period of actual entrance of the morbific agents into the organism or system. The stage of incubation is tlie period of actual devel- opment of the morbific agents within the organism, or the period of the active struggle for existence between the infecting agent and the defensive forces of the })ody. The jx'riod of in'asion is the ])criod during which th(^ infecting morbific agents, ha\ iiig won their l)attl<', the definite symptoms of disease (the prodromal stage), begin to manifest themselves. The stJiges: acme, decline, and convalescence, i\rv characterized by the height, the decline of disease, and recoNcry. The degree of infection depends upon the number of morbific agents, their \irulence, the mode of entrance, and the vital resist^mce of the b(»dy. The incubation jxTiod dejxMids upon the s|H'cific 13 194 INFECTIOUS DISEASES AND PREVENTION character of the invading morbific agents, and varies with different diseases. Decline of the disease is either sudden, by crisis, or gradual by lysis. Convalescence may also be delayed by "recurrence" or "relapse." The disease may also be of acute, subacute, or chronic, severe or mild, remittent or intermittent. Infectious diseases are termed endemic when they appear continuously in one locality, epidemic when they affect a large number of persons at one time, and pan- demic when they cover a vast area of land or several countries. The three most important features of infection and infectious disease are the following: 1. The morbific agents. 2. The portals of entry. 3. Modes, vehicles, and agents of transmission. 1. Morbific Agents. — The belief that certain dis- eases are caused by some living agents outside of the body is old and has been held by many ancient ob- servers, but the proof has only become possible after the perfection of the microscope and with the extensive research into the microorganic world which this instru- ment has made possible. To Pasteur, of France, and to Koch, of Germany, we owe the establishment upon a scientific basis of the new science of bacteriology, to the researches in which we owe the definite proof that certain diseases are du-ectly caused and are due to specific microorganisms, which invade and infect the human body and, by their activity and products, cause the pathological changes and train of sjinptoms which we call infectious diseases. (lESEIiAJ. COXSlDI-h'ATKiXS 195 Tlic iiiicnx'ir^anisnis wliicli ;ict as ninrhific a^'iits of disease arc ot" animal or xcf^etahlc orii^iii, mostly of the latter. The animal i)arasites hcloiii,' to the protozoa, insects and Worms. The vegetahle microcir^inisnis are grouped under the general f;roup of bacteria, which signify niimite uni- cellular i)lants and which are subdivided into a number of groups and types; one important sulxlivisiou being according to their external form; thus, the cocci are so named becau.se of their spherical form, the bacilli have a nxl-likc elongated form, while the si)irilli have a sj)iral form. While millions of these vegetalile microorganisms are entirely innocuous, there are among them certain species which, entering under fa\orable conditions into favor- able soil in the human organisms, become pathogenic and are to l>e looked upfjn as the morbific agents of disease. Among the more important pathogenic cocci are tiie following: Stiiphylococcus pyogenes aureus, Strej)- tococcus pyogenes, pneumococcus. and the gonococcus. The following are some of the j)athogenic bacilli: liacillus anthracis. Bacillus edematis maligni. Bacillus tetiini. Bacillus tyj)hosus, Bacillus tu})erculosis. Bacillus mallei, Bacillus lepra, Bacillus di])htheria', Bacillus influenzfe, Bacillus coli communis. Among the spirilla the following an* noted: \ibrio, cholera Asiatica, s|)irillnm of relaj)sing fever, Sj)iro- cheta pallida (Tre|)onema pallidum). lincfrrial />/.vrr;.yr.v. — Some of the diseases, the mor- bific agents of which have alrea<ly been demonstrated. 196 INFECTIOUS DISEASES AND PREVENTION are the following: Septicemia and pyemia, pneumonia, gonorrhea, anthrax, malignant edema, tetanus, typhoid fever, tuberculosis, bubonic plague, diphtheria, influ- enza, cholera, relapsing fever, yellow fever, malaria, syphihs, etc. Some of the diseases which are infectious, but the specific agents of which have not yet been absolutely demonstrated, are the following: Scarlet fever, measles, smallpox, rabies, pertussis, etc. The pathogenic action of the morbific agents upon the body may be due partly to mechanical, partly biological and partly chemical action. The very presence of the mobific agents may mechani- cally interfere with the physiological action of certain organs, causing stasis, hemorrhage, etc., or the in- creased activity of the morbific agents may cause local inflammation of tissues, infiltrations, and abscesses or the whole body may be infected by metastatic foci by means of blood or lymph, thus carrying infection to remote parts. Much of the harm done is not by morbific agents themselves, but by their chemical products, or toxins which are the results of the bacterial action upon the blood and body fluids as well as to other bacterial products, endotoxins, proteins, etc. These toxins are not as yet all known, and vary in their effects and virulence according to various factors. 2. Portals of Entry. — Infection of the body with microorganisms is by means of entrance of these or- ganisms into the body through certain portals of entry which differ with each specific bacterium, so that some CESEIiM. COXSinKh'A'rioXS 1!I7 hactrriu may lie ciitii'cly innocuous when cnlcrin^ a certiiin organ of tin- ImxIv, wliile patliogcnic and \iru- lent wluMi entoriiig anotlitT part or organ. Tlie princ'i])al ports of entry arc the skin, the respira- tory, the alimentary, and tlie genito-urinary tracts of the body. While some microorganisms may enter tlie healthy and normal skin, this is very rare, and the commonest mode of entrance is through some solution of continu- ity, through cuts, bruises, abrasions, wounds, etc. The skin as a port of entrance admits certain animal parasites, like favus, scabies, tinea, tonsurans; also through bites of insects in malaria, yellow fever, i)lague, through wounds, etc., in sx-philis, septicemia, small- pox, etc. The respiratory tract as the port of entrance admits, through the mucous membranes of the nose, eyes, ears, mouth, and tliroat, diphtheria, scarlatina, measles, influenza, pnemnonia, etc. The throat, bronchi, tra- chea, laryiLx, and lungs may be the port of entrance of tuberculosis, diphtheria, pneumonia, influenza, prr- tussis, etc. The alimentary canal as the port of entrance is open to typhoiil. cholera, d.x'sentery, etc. The genito-urinary tract as the y)ort of entrance is entered by gonorrhea, syphillis, chancroid, tuberculo- sis, diphtheria, septicemia, etc. The ditterent parts and tissues of the body react variously to micnxirganisms, while the various micro- organisms have each a predilection for certain parts of the body, in some of which they thrixc, while in others thcv succnml). 198 INFECTIOUS DISEASES AND PREVENTION ?). Modes, Vehicles and Agents of Transmission of Infec- tious Organisms. — The pathogenic bacteria are not found free in nature, but they live in the body, the blood, the secretions and excretions, the discharges of the body, the skin and the exterior of persons which they infect. Hence the principal agents of infection as well as vehicle of transmission, are man himself and animals, and their discharges. The morbific agents are found in the various parts and discharges of the body. Thus, certain bacteria may be found on the skin, in the secretions of the eye, ear, nose and throat, the sputum, the expectoration, the perspiration of the skin, the urine, the solid excreta, the secretions from wounds and abscesses, etc. All the above-named secretions and excretions may con- tain virulent morbific agents which may be trans- mitted from one individual to another. The transmission of bacteria may be direct, or in- direct, by contact or by intermediary agents and vehicles. Anything and anybody that may take up part of the secretions and excretions from an infected person and carry them to a non-infected person may serve as vehicle and agent of infection. Persons, animals, insects, food, milk, water, air, soil, and fomites may be then regarded as vehicles of infection. The most frequent and demonstrated mode of infec- tion is by direct contact of disease with the healthy, of the persons surrounding the infecterl ones, such as, physicians, nurses, etc. Insects and animals may be the sources, the vehicles, and the intermediate hosts of infection. Cl-:\i:h'M. COXSlDI'Hi'AT/OXS lll!) Animal sniirccs nt' iiilVctioiis arc traced in j^'landcrs, anthrax, and (»thcr int'ccti()U> animal diseases, in Favus, soai)ies, etc., or tliroii^li hited, as in ral)ies, plaj^nie, etc. Animal vehicles of iiiteetioii may serve in almo.st all infectious diseases, the morbific elements of which they may carry from diseased to healthy upon their bodies, or by means of parasites ni)on them, such as fleas, bugs, etc. Insect sources of infection carry infective material upon their bodies, legs, and wings, and deposit the same infective materials upon the bodies of healthy persons, on their mucous membranes, on wounds, in the food. milk, water, etc. It has been clearly demonstrated that insects — flies, fleas, lice, bugs, roaches, etc. — may and do transmit infective material from cholera, typhoid, tuberculous and other patients, and are capable of carrying infec- tion to healthy persons, either indirectl.x' to foodstuffs, directly by means of their bites. That some insects, notably the mos(|uito. may be- come the intermediary hosts of several infectious diseases, 1ms been demonstrated in the casi' of malaria, of yellow fever, and of elei)liantiasis. In these diseases the infecti\e j)arasite is sucked up from the blood of a human being by the m()S(|uito. and within the body of the insect the infective agent undergoes further development, after which it may cause the disease when inoculated by tiie bite of the mosquito into a healthy person. The spread of infectioit by food has also been demon- strated, and is an accepted fact. Meat. milk, and other article-, of food nia\ become 200 INFECTIOUS DISEASES AND PREVENTION contaminated with infective material containing mor- bific agents, and such food and food products may upon ingestion by healthy persons cause certain in- fectious diseases. This is the case especially with those diseases the morbific agents of which have their port of entry in the digestive tract. The germs of typhoid, cholera, dysentery, and prob- ably tuberculosis are those which, if carried into the alimentary canal by various articles of food, may cause those diseases. Infection may also be carried by fruit, vegetables, bread, milk, water, candy, and other food articles which are used without cooking, and which may carry infective material from the diseased to the healthy persons. The soil as a source and vehicle of infection is claimed in plague, cholera, and other diseases, but its direct connection with diseases, except through the means of infected water, has not been directly demonstrated, except in hookworm disease. Air as a vehicle of infection may serve through the medium of dust floating in the air, or through the drop- lets which are exhaled and expired by the tuberculous patients. Infection by Fomites. — By fomites are understood various articles and substances in use by man which may carry infectious material and thus serve as vehicles of infection. Money, clothes, rags, bedding, underwear, books, mail, and the thousand and one other articles used by diseased persons, may be in use or handled by sick persons, may contain discharges from patients and mav carrv these from them to healthv individuals. rUISCII'I.KS AM) I'h'AcriC/-: of I-UFA i:\Tin\ L'ltl 'I'lir iiiipditjiiicc of tomitt's liiis hccii <:rc;itly (»&lt;t- t'stiiiiMti'd. owiii^ to tlic iiii^mi(|cixi;iii(|iiiir ,,t' the exact iiatiirt' of iiiorl)ific ai^ciits and tlu-ir activitv, aiirl it is at pirst'iit claiiiUMl that fumites have nothing; to do in the case of some diseases, wliile tiicir importance in otiiers has Keen also overrated. PRINCIPLES AND PRACTICE OF PREVENTION. Nearly one-third of all the deatlis caused hy all diseases is due to the di.seases termed infectious or comniiuiicai)le. Tlie mortality statistics of the la.st census show that tile death-rate from all causes per 100,000 population was 15S8.0. The death-rate from only II of tJie infectious diseases was 42.1, as follows: Tuberculosis of the lungs 154.7 Pneumonia 155.4 Diphtheria 27.7 Typhoid fever 23 . 3 Influenza 20.4 Scarlet fever 10.5 Whooping-cuuKh 10.5 Measles 99 Dysentery 8 2 Miliaria 4 0 Smallpox 13 If we add to these the 113.8 fleaths due to diarrhea and enteritis, mostly infectious, the percentage of infectious di.sea.ses will exceed one-third of all the cases of death. Infectious di.sea.ses may al.so he termed jtrrrrntnhir (hseajies. In the progress of liygiene and j)ulilic health there has been prarticall.x in all conntries of the world a stead'. regular and drci.l.d reduction in tlu' 202 INFECTIOUS DISEASES AND PREVENTION mortality from infectious diseases. The last United States census has shown a decided lowering in the death- rate from all epidemic diseases. This is specially noted when the mortality for individual diseases is considered. In the very short period between 1900 and 1909 the death-rate from tuberculosis of the lungs in 1909 is shown to have been only 73.0 per cent, of that in 1900. The death-rate from tuberculosis of the lungs in the United States Registration Area has been reduced from over 175 in 100,000 in 1900 to less than 125 in 1913. According to another table, the percentage of decrease in the death-rate from pulmonary tuberculosis in the period between 1890 and 1912 was not less than 48.9. The percentage of decrease from typhoid fever has been shown to be 65.2 between the years of 1890 and 1912. Between the period of 1881 to 1915 the death- rate from typhoid fever in America has decreased from nearly 65 per 100,000 population to about 11. The decennial rate was 51.9 for the period from 1881 to 1890; 39 for the period of 1891 to 1900; and 29 for the period of 1901 to 1910. The mortality-rate from diphtheria and croup has been reduced in the United States Registration Area in the period of 1900 to 1914 from over 40 per 100,000 to less than 20. In certain countries, for instance, the cities of Den- mark, the mortality-rate from diphtheria and croup has been reduced from 134 per 100,000 population in the pre-antitoxin period, to only 7.9 during the anti- toxin period. rh'i.(!i'i.i-:s AM) I'hwcrici': or I'REVEsrios 20:^, IV'rliiii)s 110 greater pi'o^rcss has v\rv \vv]\ >li(i\ii in progress of liy^iciic than is cxcmplilicd 1)\ tlir i-cdnc- lidii in mortality of sudi pn-xcntalilc diseases as small- pox and vcllow fcNc?". Siiiallpox has ix'cn rcilnccd from one of the most deadly diseases to one of tiic most nc^dii^nMc In cer- tain countries, for instance, as in Prussia, it has heen practically wiped out. In New ^'ork City there wen- only 2 cases of smallpox in IDKl. Since tlie discovery of the eoninuniication of yellow fever throu^'h the bite of an infected nioscpiito, this disease, whicli