Plague in the Continental United States, 1900-76

ELIZABETH T. ANDERSON, RN, MS

BUBONIC PLAGUE, like cancer to-day, was probably one of the mostdreaded and feared diseases a cen-tury ago, and even today it is ofinterest (1-3). Is interest todaymerely of historic note? The fol-lowing review of the history ofplague in the continental UnitedStates provides a context for ourcurrent knowledge, points out thatthe threat of human plague stillexists, and alerts public healthworkers in certain areas to thispotential danger.Even before the first case of

plague was documented in theUnited States, Surgeon GeneralWalter Wyman noted in a pam-phlet published for the use of hismedical officers (4a):

The appearance of the plague inSantos, Brazil, in October 1899 marks animportant epoch in plague literatureas furnishing the very first recordedinstances of the occurrence of the diseasein the Western Hemisphere.

Shortly thereafter, plague was dis-covered in San Francisco. OnMarch 6, 1900, the body of a Chi-nese worker was found in thebasement of the Globe Hotel andtransferred to an undertaker. Anautopsy revealed large inguinalnodes suggestive of plague, andthe city physician notified the cityhealth officer and bacteriologistWilfred H. Kellogg of this find-

ing. Organisms with characteris-tics of the plague bacillus werediscovered by Kellogg in smearsof lymph fluid (5). The ChiefQuarantine Officer at the U.S. Ma-rine Hospital Service at AngelIsland, Dr. Joseph Kinyoun, wasnotified of Kellogg's discovery.Kinyoun recommended that ex-posed Chinese of San Franciscobe inoculated with antipest serumand that the entire area be fumi-gated. Twelve blocks of China-town were surrounded by policein search of persons who mighthave the disease.However, what might have been

a routine investigation of a poten-tially major epidemic became amajor concern, not only for thehealth of the citizens but alsofor commercial interests. A bitterattack was launched againstKinyoun and the board of health.Pressure became so intense thatthe initial quarantine was liftedafter only 60 hours. But, byMarch 11 although the bodies ofthe Chinese dead were hidden-two more cases of plague were de-tected in Chinatown (5).The newspapers, which had

heretofore refused to print thenews, could no longer ignore it.Soon the nation knew that plagueexisted in California. The Gover-nor of California nevertheless con-

ducted an investigation supportedby large businesses, the board oftrade, the chamber of commerce,and the railroad industry. It wasconcluded from this investiga-tion that plague "Did not norever did exist in California" (5).The political battle waged overthe need to quarantine part ofSan Francisco and to fumigate theChinese community has beencalled "One of the sorriest epi-sodes in American medical his-tory" (5a).By 1904, 118 of 121 persons re-

ported to have had plague haddied. Kinyoun had resigned fromFederal service. An order fromPresident McKinley to limit travelof orientals was refused. And thenew Governor of California recog-nized the existence of plague andcooperated fully toward its eradi-cation. Rat proofing of buildingshad begun, and the outbreak hadended (6).Although the exact method by

which plague entered San Fran-cisco is not known, the data avail-able indicate that the population

LI Tearsheet requests to Eliza-beth T. Anderson, Assistant Pro-fessor, Texas Woman's University,College of Nursing, 1130 M.D.Anderson Blvd., Houston, Tex.77030.

May-June 1978, Vol. 93, No. 3 297

was at risk of an outbreak. Urbanplague-plague that is trans-mitted in a rat-flea-rat cycle withman as an incidental host-de-pends on a dense rat populationwhich harbors a high flea popula-tion, optimally the oriental ratflea, Xenopsylla cheopsis (7). Thedense rat population must haveexisted in Chinatown because thepoor sanitation there has beenwell documented. The plaguebacillus most likely was intro-duced by ships from the Orient.Bubonic plague was pro-

nounced "eradicated" in 1904 pri-marily because of three factors:(a) bitter opposition to continu-ing eradication efforts that hurtbusiness and trade, (b) an absenceof new cases in man, and .(c) in-adequate epidemiologic informa-tion (8). If the rat population hadbeen surveyed at the time, how-ever, it would have been evidentthat the disease had not beeneradicated. After the 1906 earth-quake followed by fire in SanFrancisco, "Rubbish, garbage, andhuman and animal wastes piledhigh. Rats multiplied and fat-tened in the filth, and passed theirfleas on to the ground squirrelsin the rural areas" (4b). FromMay 30, 1907 to June 30, 1908,159 cases of plague and 77 deathswere reported (4c).

Between 1900 and 1908 it wasdiscovered that the ground squir-rel population of California, aswell as the rat population, was in-fected with the plague bacillus.Two theories concerning the in-fection of wild rodents, referred toas sylvatic plague, prevail: (a) thatthey became infected through im-portation from the urban rats and(b) that plague had existed in thewild rodents but had not beenidentified previously (9-11). Anentry by Dr. Rupert Blue in theSan Francisco plague Journal in1904 attests to the possibility that

sylvatic plague was probably quitewidespread ,(4b):

June 18. Two boys died. Had beenshooting squirrels in Contra CostaCounty, May 29, 30, 31, . . . This marksthe 3d or 4th death in the past year tobe apparently associated with groundsquirrel infection, and that the squirrelsof Contra Costa County are alreadyinfected seem to be foregone conclu-sions. These animals infest the wholestate, their burrows being a continuouschain from one end to the other.

Sporadic cases of human plagueof sylvatic origin were reportedfrom Seattle to southern Cali-fornia, giving some hint of theextent of infection in the rodentpopulation during the early 1900s.Annual reports of the SurgeonGeneral reflected concern overthis newly discovered locus ofplague. Regular notations weremade of numbers of rodents (rats,squirrels, and others) found andinspected, as well as the numbersinfected.This concern was well founded.

On August 15, 1919, after huntingin the Berkeley Hills and bring-ing home a squirrel, a man con-tracted plague and subsequentlydied. This case is of particularnote for several reasons: (a) theman developed secondary plaguepneumonia (the major form inwhich plague can be transmittedfrom man to man), ,(b) this wasthe "first instance of an epidemicof pneumonic plague on theWestern Hemisphere" (12), (c) theplague was of sylvatic origin, .(d)of the 13 persons who later con-tracted plague, 12 died, and (e) themanner in which the epidemicwas contained by hospitalizationand isolation is a somewhat classicexample of containment (12).On the heels of the outbreak

just described, plague was re-ported from yet another area ofthe country. The Surgeon Gen-eral's 1914 report stated that therewas continued world prevalenceof plague with "no unusual out-

breaks of importance." However,it went on (13a):

During the last 20 years [plague] hasbeen traveling to all corners of theearth, following the commercial routes,especially water routes. Ships carry ratsand rats carry plague, so that in theabsence of special precautions to preventthe introduction of the disease in thisway it would be suprising and quiteaccidental if ports of any size haveescaped the infection.

How prophetic these wordsmight have seemed to the peopleof the Gulf Coast had they seenthem 5 years later when humanplague was recognized nearly si-multaneously in Galveston, Beau-mont, and Pensacola,(14). Closelyfollowing these outbreaks, caseswere also reported from NewOrleans and Port Arthur; a totalof 71 cases with 31 deaths resultedfrom these outbreaks.

Shortly thereafter, yet anotherepidemic was in progress. Again,plague pneumonia was the majorkiller. A 2-week outbreak in Octo-ber and November 1924 occurredin the primarily Mexican sectionof Los Angeles. Of 39 human casesreported, 28 were in Mexicans;a total of 33 persons died. Theepidemic was contained, accord-ing to Wayson ,(15) who comparedit with the earlier epidemic in SanFrancisco's Chinatown, becausethe Mexicans were "easier to dealwith" and did not hide their dead.Rat proofing of buildings in a

number of port cities seemed tobe paying off in more than adiminution of plague cases. TheSurgeon General's 1917 reportfrom New Orleans pointed outsome of the "fringe benefits" (13b):The average number of fleas per rathad lessened; the general health of thecommunity was improved; and it is alsoestimated by the fire marshall that asa result of rat-proofing the number offires had been reduced.

Additionally, Oakland, Calif., wasdeclared "free from plague infec-tion" in 1925, and restrictions

298 Public Health Reports

Figure 1. Reported cases of human plague, United States, 1900-75

150

100

10

1900 1910 1920 1930

were removed from vessels movingin and out of the area (13c).

It seemed that urban plaguewas waning after the Gulf Coastoutbreak and that plague mightbe approaching elimination in theUnited States. Yet, reports of in-fected wild rodents became more

frequent in the 1930s. Followingfew cases and few reports of in-fected rodents (although the deathof one person was attributed toinfected ground squirrels in 1928),the Surgeon General's reports con-

tained increasingly frequent nota-

tions about plague infections inwild rodents and their fleas. In-fected ground squirrels in Cali-fornia were first mentioned in1914 (13a) and then from 1935 to

1937 they were reported to be inOregon, Montana, Idaho, Nevada,and Utah (13d, e, f). The list ofinfected animals continued to ex-

pand-prairie dogs, chipmunks,and even some birds were impli-cated in the spread of plague (16).Also, most wild rodents have beenimplicated, and in 1972 the firstconfirmed direct association of an

1940 1950Year

1960 1970

infected wild carnivore (bobcat)with plague in man was reported(17).

Summary of EpidemiologyFrom 1900 to 1975, a total of 617cases of human plague were re-

ported (fig. 1). The majority ofpersons were affected during thedecade 1900-10 by ratborne bu-bonic plague. Although this formof plague has diminished to thepoint of being of historical inter-

est, it has been supplanted by anincreasing prevalence of sylvaticplague in the United States.Of the 100 cases of human

plague reported since 1950, 22percent of the 54 males and 13percent of the 46 females died(fig. 2). Eighty-one percent of thecases occurred in the age groupunder 30, reflecting the youngerpersons' greater exposure to in-fected animals (fig. 3.).No particular race seems to be

inherently more susceptible toplague infection. Although someracial or ethnic groups, such asthe Chinese in San Francisco, theMexicans in Los Angeles, andrecently the Navajos in NewMexico (18), have been affected byoutbreaks, the first two groupswere living in unsanitary condi-tions that undoubtedly con-tributed to a large population ofrats. Moreover, the Navajos notonly live in areas in which plagueis enzootic to the wild animalpopulations but they also includeprairie dog in their diet.

In the first two decades of thiscentury, sailors and dock workerswere at greater risk than othersof contracting plague. As sylvaticplague became of increasing con-cern, however, the risk becamegreater for others who work out

Figure 2. Reported cases of human plague, United States, 1950-75, by age and sex

14

12

cna)U) 10

O8-

E6

z 4-

* MaleE Female

* Death

0 10 20 30 40 50 60 70 80Age

May-June 1978, Vol. 93, No. 3 299

U)a)

U)0

a)-0Ez

50

20

Figure 3. Reported cases and deaths from human plague, United States,1950-76, by age groups

of doors. Several occupations ofpersons who were infected were

sheepherder, geologist, farmer,telephone lineman, and hunter.

Rat-borne plague in the UnitedStates was first reported in SanFrancisco and later in Galveston,New Orleans, and Pensacola (fig.4). No human cases of sylvaticplague origin have originated eastof the 100th meridian (18a). Thereason for this is unclear, butKartmen (18) suggested that densepopulations of ground squirrelsand prairie dogs do not extendbeyond the 100th meridian. Casesin man are being reported more

frequently from New Mexico andArizona and less so from Statesfurther west. The numbers ofhunman cases reported in the af-

fected States are shown in figure 5.Of the 80 human cases of

plague of sylvatic origin reportedfrom 1903 to 1966, 54 occurred inJune, July, and August, but rat-borne plague was most prevalentin September and October (18b).

ConclusionsThe "Black Death" of earliertimes does not seem to be a threatto the health of the U.S. public.However, we cannot yet declareplague eradicated, as was done in1904, because the United States"harbors a vast focus of wild ro-dent plague," and this infectioncan spill over into domestic ratsand become a potential threat topeople. Thus, the possibility ofsecondary plague pneumoniaexists with a great risk of spreadfrom person to person (18c).Although the absolute numbers

of cases of human plague aresmall, they have been increasingin recent years. As shown in thetable, the case fatality rates arealarmingly high despite the treat-ment capabilities we now possess.A major factor in the continuing

Figure 4. First reported case' and last reported case of human plague(in white type), United States, 1900-76, by State and year

300 Public Health Reports

18

16

14

12

en 10a)en _U)

8

6

4

2

00 10 20 30 40 50 60 70 80

Age

Figure 5. Reported cases of human plague, 1900-76, by State

7-7~~~~.4~~~~~~~~~~~ s-

~~~.~~~~J4'4~ ~~~Na

30~~~~~~~~~~~~~~~~~~~~~~~~~~~~~3 ..g .f4i* ..

5 0~ ~ ~ ~ ~ ~ 4

10 ..

14-~ ~ ~ I.

00~

1900 1910 1920 1930 1940 1950 1960 1970 1980

Year

high case fatality rates may bethat medical personnel do not sus-pect and diagnose plague earlyenough. It is particularly impor-tant for public health workers inthe Western States to be alert tothe possibility of plague infection.

Plague is a disease of rodentsthat is spread by fleas. Man is in-cidental to the cycle of this in-fection. Yet, as man invades thenatural habitats of wild rodents-camping, hunting, and exploringthe wilderness-he becomes moreand more at risk of acquiring the

Human plague cases and fatalities, United States, 1900-76

Years Cases Fatalities Case fatality rate

1900-09 ................. 332 228 68.71910-19 ................. 69 34 49.31920-29 ................. 99 69 69.71930-39 ................. 10 4 40.01940-49 ................. 10 6 60.01950-59 ................. 10 4 40.01960-69 ................. 28 7 25.01970-76 ................. 59 8 13.5

SOURCES: Reference 10 and Morbidity and Mortality Weekly Reports, Center for DiseaseControl, vols. 18-25, 1970-76.

disease that some public healthworkers once believed had beeneradicated.

References1. Camus, A.: The plague. Translated

from the French by Stuart Gilbert.Vintage Books, New York, 1972.

2. McNeil, W. H.: Plagues and peoples.Anchor Press, New York, 1976.

3. DeFoe, D.: A journal of the plagueyear. Penguin Books, Baltimore,1966.

4. Furman, B.: A profile of the UnitedStates Public Health Service, 1798-1948. DHEW Publication No. (NIH)73-369. U.S. Government Printing

Office, Washington, D.C., 1973, (a)p. 217; (b) p. 254; (c) p. 255.

5. Lipson, L. G.: Plague in San Fran-cisco in 1900: The United StatesMarine Hospital Commission toStudy the Existence of Plague inSan Francisco. Ann Int Med 77: 304(1972); (a) p. 310.

6. Kellogg, W. H.: Present status ofplague, with historical review. AmJ Public Health 10: 835-844 (1920).

7. Reed, W. P., Palmer, D. L., Williams,R. C., and Kisch, A. L.: Bubonicplague in the Southwestern UnitedStates. Medicine 49: 467 (1970).

8. Creel, R. H.: Plague situation in theWestern United States. Am JPublic Health 31: 1156 (1941).

9. Meyer, K. F.: The prevention ofplague in the light of newer knowl-edge. Ann NY Acad Sci 48: 429(1947).

10. Beasley, P.: Human plague in theUnited States. JAMA 208: 1024, May12, 1969.

11. Pollitzer, R.: Plague. World HealthOrganization, Geneva, 1954, p. 51.

12. Kellogg, W. H.: An epidemic ofpneumonic plague. Am J PublicHealth 10: 599 (1920).

13. U.S. Treasury Department: Annualreports of the Surgeon General cfthe Public Health Service of theUnited States. U.S. GovernmentPrinting Office, Washington, D.C.,(a) fiscal year 1914, p. 292; (b) fiscalyear 1917, p. 214; (c) fiscal year 1925,p. 1849; (d) fiscal year 1935, pp. 824,1081; (e) fiscal year 1936, p. 1019;(I) fiscal year 1937, p. 1048.

14. Boyd, M. F., and Kemmerer, T. W.:Experience with bubonic plague(human and rodent) in Galveston,1920. Public Health Rep 36: 1754-1764 (1921).

15. Wayson, N. E.: Plague: A discussionof its trend in the United States.Clinics 2: 868-874 (1943).

16. Jellison, W. L.: Sylvatic plague:Studies of predatory and scavengerbirds in relation to its epidemiology.In Annual report of the SurgeonGeneral of the United States for thefiscal year 1939. U.S. Treasury De-partment, pp. 792-798.

17 Poland, J. D.: Human bubonicplague from naturally infectedcarnivore. Am J Epidemiol 97: 332-337 (1973).

18. Kartmen, L.: Historical and oeco-logical observations on plague inthe United States. Trop Geogr Med22: 268 (1970); (a) p. 261; (b) pp.264, 265; (c) p. 274.

May-June 1978, Vol. 93, No. 3 301