PUBLIC HEALTH REPORTS

VOL. 38

JANUARY 26, 1923.

No. 4

EIGHT YEARS OF EPIDEMIC POLIOMYELITIS IN MONTANA.

By JOHN J. SIPPY, M. D., Director, Division of Child Welfare, Montana State Board of Health; Collaborating Epidemiologist, United States Public Health Service.

In 1915 there were reported in Montana 2 cases of epidemic poliomyelitis with 1 death. In 1916 there were reported 111 cases and 24 deaths, a morbidity rate of 24.2 and a mortality rate of 5.2 per 100.000 population. While these cases and deaths were reported from 12 counties, there occurred a distinct explosive outbreak with Yellowstone County and the city of Billings as foci, the majority of cases occurring within that county and in counties immediately surrounding the area of the outbreak, extending from Miles City, Custer County, on the east, to Livingston, Park County, on the west. Sporadic cases were reported in Cascade, Sheridan, and Toole Counties.

The first case to be diagnosed occurred July 11 at Pryor, an inland point on the Crow Indian Reservation in Big Horn County, 25 miles south of Billings and 18 miles cast of the nearest railroad point, Fromberg, in Carbon County. There was a history of previous visits and railway travel by Indian citizens of the reservation to both Fromberg and Billings. While difference of opinion existed as to the original source of the outbreak, the pandemic prevalence of the disease in Eastern States, beginning in May, 1916, suggests the source, and a large exodus of carriers from the eastern infected areas indicates the probable means of transmission to the Montana districts attacked.

The area immediately surrounding Billings and extending into that portion of Carbon County adjoining the Crow Reservation 50 miles southwest of Billings, suffered most. Seventeen cases and 3 deaths were reported among Indians at Pryor (see article by J. A. Murphy, Medical Supervisor U. S. I. D., Jour. Am. Med. Assn., vol. 67, No. 17, October 21, 1916, p. 1247).

Since the abortive type of the disease was not generally recognized, and it was the rule to report only those cases manifesting frank paralysis, it may be assumed that the number of cases reported reflects a minority of the actual infections occurring. At any rate,

surveys made in later years to discover the actual number of crippled children in Montana counties reveals a surprising number of paralyses referable to that year, many of which received no medical attention. It is difficult to estimate the actual number of all types of cases occurring in 1916; but it is safe to admit that probably not more than 20 to 25 per cent were detected and reported. In this event the actual fatality rate of 21.6 would be materially reduced.

The annual prevalence of epidemic poliomyelitis during the following years is given in Table I. The morbidity and mortality rates are rates per 100,000 population; the fatality rate is the percentage of cases terminating fatally.

TABLE I.—Prevalence of poliomyelitis in Montaña, 1917–1922.

During the period 1917 to 1921, inclusive, all cases were sporadic and widely distributed, with only two exceptions:

(1) Of the 37 cases and eight deaths occurring in 1917, distributed in 10 counties, 12 cases and two deaths occurred in Cascade County, with the city of Great Falls as a focus. The fatality rate in this outbreak was 16.7 per cent as compared with the general State rate of 21.6.

(2) Of the 27 cases and five deaths occurring in 1920, 9 cases and three deaths occurred in Ravalli County, with the city of Hamilton as a focus. In this little outbreak the fatality rate was 33.3 per cent, as compared with a general State average of 18.5. However, the number of cases reported from Hamilton covers only those with frank paralysis. Investigation indicated a large number of cases of the abortive type, approximating 80 to 100. In fact, a general epidemic of so-called "bilious attacks," "la grippe," "colds," and "tonsillitis" occurred among both children and young adults during the period in which 9 cases of poliomyelitis were reported; and several of these 9 patients gave history of recent previous contact with apparently harmless "colds (?)." An unusual feature of this outbreak was its appearance in late September, October, and November, months in which early winter weather occurred.

During this entire period (1917-1921) only one case of poliomyelitis was reported in Yellowstone County (1 case in 1921); but in 1922 it again became an epidemic focus.

Of the 48 cases and seven deaths occurring in 1922, 42 cases and four deaths occurred in Yellowstone County-34 cases and four deaths in the city of Billings, and 8 cases with no deaths in the rural area immediately adjacent. Cases occurred in other counties as follows: Sweet Grass, 1 in January; Flathead, 1 in February; Wheatland, 1 in May; Rosebud, 1 in August; Wibaux, 1 in August; Stillwater, 1 in September.

The first case in Yellowstone County occurred January 6. No more cases appeared until July 14. The cases occurred, by months, as follows: January, 1 case; July, 6 cases; August, 26 cases; September, 9 cases.

The last case appeared September 15. Table III gives a brief history of these 42 cases. Interest is attached through the fact that the antipoliomyelitic serum advocated by Dr. E. C. Rosenow was used in the treatment of a large group of cases.

Analysis reveals that of the 42 cases, 10, or 23.8 per cent, were diagnosed as abortive types; 25, or 59.5 per cent, were afflicted with frank paralyses; and 7, or 16.7 per cent, were of the bulbar types. From footnotes it may be observed that 15 other persons gave a history of having had abortive attacks; and it was freely admitted that many persons in immediate neighborhoods where the disease occurred were afflicted with symptoms suggestive of abortive poliomyelitis.

The results of treatment of the 42 known cases is given in Table II. TABLE II. Results of treatment of 42 cases in Yellowstone County.

Since a large number of abortive cases occurred which received no treatment and which can not be computed, it is only fair to omit all abortive cases from the tabulation. In this event we find that of the 27 cases of the paralytic or bulbar types treated by serum, 52.9 per cent made complete recoveries, 40.7 per cent have paralysis remaining, and 7.4 per cent died. Of the 5 cases treated symptomatically, 20 per cent made complete recovery, 40 per cent have paralysis remaining, and 40 per cent died.

Because of the small number of cases in each group and especially in the group not receiving serum, conclusions are difficult; but on the face of the data it might appear that the use of serum is advantageous. In several instances it was noted that following spinal puncture for the purpose of diagnosis, improvement began immediately, even before the administration of serum. The possibility

of relief afforded by spinal puncture should be eliminated as a factor if curative value of serum is to be finally determined.

CONCLUSIONS.

(1) The study of poliomyelitis in Montana indicates that the disease does not originate without previous contact with infected individuals. These infected persons may be only (a) immune carriers, (b) sufferers of mild or abortive attacks, or (c) recognized cases.

(2) With exception of a few cases in isolated rural areas, outbreaks tend to occur along principal interstate and intrastate travel

routes.

(3) Considerable distances between Montana cities afford some natural protection against rapid spread of the disease.

(4) Without large, congested population centers, little opportunity is afforded for acquisition of immunity by contact with mild infections. Rapid spread and a fatality rate higher than usual may ordinarily be expected in isolated communities when infection is introduced.

(5) Isolation or quarantine control measures are clearly ineffective without a common knowledge of the importance of recognition of the mild and abortive type cases.

(6) The value of antipoliomyelitic serum is regarded as neither proved or unproved. Its use appears to be without harmful results, of possible advantage, and apparently worthy of further administration and study.