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Chapter 6 - Mumps




Joseph Stokes, Jr., M. D.


Mumps remains a disease of the greatest importance in military medicine. In all wars, including World War II, periods of mobilization have been marked by sharp increases in incidence rates of this disease.

In World War I, the total number of cases admitted to hospital and quarters for mumps was 230,356, an annual rate of 55.80 per 1,000 average strength. Except for influenza and gonococcal infection, the incidence was higher for mumps than for any other communicable disease. The rates were considerably higher among Negro than among white enlisted men, being 134.75 (total admissions 38,619) and 49.99 (total admissions 179,948), respectively. The higher rates for Negroes can probably be accounted for by the rural origin of many of the Negro enlisted men in that war.

Although a few enlisted men were discharged from the service on account of disability, the reasons for such discharges presumably were for conditions other than mumps itself (for example, sequelae).

During World War I, the Army lost 3,884,147 man-days from duty, a figure which gives a noneffective rate of 2.58 per 1,000 strength---a noneffeetiveness which was third on the list caused by important diseases. In this respect, the figures were also considerably higher (about three times) for Negro than for white enlisted men, the rates being 6.28 and 2.30 per 1,000 average strength, respectively. The disease was widespread throughout all Army posts in the United States, with particularly severe outbreaks in Camp Beauregard, La., Camp Wheeler, Ga., and Camps Bowie and Travis, Tex., where the admission rates were all over 205 per annum per 1,000 average strength. In 1918 and 1919, there was a marked seasonal incidence, with peaks in January and February of both years. Overseas, in the American Expeditionary Forces, the admission rate for Negroes continued in a ratio of about 3:1, and the total rate for all enlisted men in Europe was 50.93 as compared with a rate of 81.40 for enlisted men in specified camps in the United States. Undoubtedly, the greater number of unseasoned recruits in the Army in the continental United States was responsible for this higher admission rate.

1 (1) The Medical Department of the United States Army in the World War. Statistics. Washington: Government Printing Office, 1925, vol. XV, pp. 86,110. (2) The Medical Department of the United States Army in the World War. Communicable and Other Diseases. Washington: U. S. Government Printing Office, 1928, vol. IX, pp. 451-462.



In all wars, including World War II, the primary problem presented by mumps has been the length of time lost from duty following the complication of orchitis, which occurs in about 30 percent of all cases. Moreover, the temporary disability caused by orchitis is frequently increased by psychological distress. In addition, the fact that mumps has a relatively long incubation period and a slower mode of transmission than measles and chickenpox prolongs the outbreaks, causes uncertainty and inconvenience, and, therefore, seriously interferes with active-duty performance.


The concept of mumps held during World War I has been considerably revised as the result of experimental studies starting with the transmission of mumps by filtered (Berkefeld V and N filters) salivary secretions to the Macacus rhesus monkey by Johnson and Goodpasture 2 in 1934 and of mumps virus to the chick amnoitic sac by Habel 3 and by Levens and Enders 4 in 1945. The work in the monkey and chick embryo--- particularly in the latter---led quickly to the following important advances which occurred just before and during World War II:

1. The development of a skin test for susceptibility both from the monkey's infected parotid gland and from the infected amniotic fluid of the chick embryo. 5

2. The development of complement fixation tests.6

3. The development of hemagglutination studies.7

4. The demonstration of the frequent presence of mumps meningoencephalitis, and at times orchitis, without parotitis or other noticeable glandular reaction.8

5. The production of apparently solid immunity under field conditions as the result of reaction to mumps virus irrespective of severity of symptoms, size of glands, or whether single or multiple glands are involved.

6. The demonstration that about 40 percent of cases of mumps are

2 Johnson, C. D., and Goodpasture, E. W.: An Investigation of the Etiology of Mumps. J. Exper. Med. 59:1-19, January 1934.

3 Habel, K.: Cultivation of Mumps Virus in the Developing Chick Embryo and Its Application to Studies of Immunity to Mumps in Man. Pub. Health Rep. 60: 201-212, 23 Feb. 1945.

4 Levens, J. H., and Enders, J. F.: The Hemoagglutinative Properties of Amniotic Fluid From Embryonated Eggs Infected With Mumps Virus.Science 102: 117-120, 3 Aug. 1945.

5 (1) Enders, J. F.: Observations on Immunity in Mumps. Ann. Int. Med. 18: 1015-1019, June 1943. (2) Enders, J. F., Kane, L. W., Maris, E. P., and Stokes, J., Jr.: Immunity in Mumps. V. The Correlation of the Presence of Dermal Hypersensitivity and Resistance to Mumps. J. Exper. Med. 84: 341-364, October 1946.

6(1) Enders, J. F., and Cohen, S.: Detection of Antibody by Complement Fixation in Sera of Man and Monkey Convalescent From Mumps. Proc. Soc. Exper. Biol. & Med. 50: 180-184, May 1942. (2) Henle, G., Henle, W., and Harris, S.: The Serological Differentiation of Mumps Complement-Fixation Antigens. Proc. Soc. Exper. Biol. & Med. 64: 290-295, March 1947.

7 See footnote 4.

8 Kane, L. W., and Enders, J. F.: Immunity in Mumps. III. The Complement Fixation Test as an Aid in the Diagnosis of Mumps Meningoencephalitis. J. Exper. Med. 81: 137-150, January 1945.


clinically inapparent but, nevertheless, both transmit the virus to susceptible contacts and become solidly immune just as readily as the apparent cases.9

7. The demonstration of the period of infectivity of human saliva from about 48 hours before the onset of the symptoms to about 6 or 8 days after their onset.10 These advances have permitted a fairly clear understanding of the etiology and epidemiology of the disease.

In addition, methods of active immunization 11 of increasing effectiveness have been developing and, while not as yet suitable for wide-scale use in the armed services, may soon become so if the early results are widely confirmed.


In World War II, as in World War I, large epidemics in young adult males differed considerably from epidemics in children before puberty. In epidemics in children, approximately 75 percent of all cases of clinical mumps (omitting inapparent mumps) belong to the full-blown type without complications. In contrast, epidemics in the United States Army may be divided roughly into three groups of approximately equal size with the following distinguishable characteristics: (1) A short course of the disease with signs and symptoms which are insignificant, (2) full-blown disease with marked swelling of the salivary glands but no complications, and (3) severe disease with the complications of epididymo-orchitis or meningoencephalitis, or both .12 Table 25 shows incidence of mumps in the United States Army during World War II.

TABLE 25.-

Incidence of mumps in the

U. S. Army, 1942-45

9 (1) Maris, E. P., Enders, J. F., Stokes, J., Jr., and Kane, L. W.: Immunity in Mumps. IV. The Correlation of the Presence of Complement-Fixing Antibody and Resistance to Mumps in Human Beings. J. Exper. Med. 84: 323-339, October 1946. (2) See footnote 5 (2), p.136.

10 Henle, G., Henle, W., Wendell, K. K., and Rosenberg, P.: Isolation of Mumps Virus From Human Beings With Induced Apparent or Inapparent Infections. J. Exper. Med. 88: 223-232, August 1948.

11 (1) Stokes, J., Jr., Enders, J. F., Maris, E. P., and Kane, L. W.: Immunity in Mumps. VI. Experiments on the Vaccination of Human Beings With Formolized Mumps Virus. J. Exper. Med. 84: 407-428, November 1946. (2) Enders, J. F., Levens, J. H., Stokes, J., Jr., Maris, E. P., and Berenberg, W.: Attenuation of Virulence With Retention of Antigenicity of Mumps Virus After Passage in the Embryonated Egg. J. Immunol. 54: 283-291, November 1946.

12 McGuinness, A. C., and Gall, E. A.: Mumps at Army Camps in 1943. War Med. 5: 95-104, February 1944.


As in World War I, the spread of mumps through Army posts was always comparatively slow in contrast with that of such diseases as epidemic influenza. This may be illustrated by a study conducted in 1944 under the auspices of the Commission of Measles and Mumps at Camp McCoy, Wis., where the peak of the epidemic (1,378 cases in all) was not reached until its 17th week, while the admission rate did not drop below 30 per week until the 26th week of the outbreak. The spread of mumps over this epidemic period is shown in chart 17. Chart 18 shows the spread of mumps in cases admitted from a single company over a 17-week period -a characteristically slow spread even among men who are closely and continuously in contact to each other. It has been uncommon for more than about 10 percent of the men in one company to develop mumps in a single respiratory season.

The Camp McCoy study, which included additional figures from several Army posts also shows the relationship between the day of onset of orchitis

CHART 17.-Spread of mumps in 1,878 cases admitted to the station hospital at Camp McCoy, Wis., over a 31-week period


CHART 18.- Spread of mumps in 29 cases from one company admitted to the station hospital at Camp McCoy, Tis., over a 17-week period

and the day of onset of the preceding parotitis as well as the day of onset of meningoencephalitis following parotitis.

In severe cases of epididymo-orchitis, the operative procedure of orchidotomy, as first suggested by Smith 13 and later fully confirmed in its value by Wesselhoeft and Vose,14 was successfully performed at Camp McCoy. The incision of the firm encapsulating tunica albuginea may well have prevented sterilization of one or both testicles when this complication was particularly severe and may be now considered as a well-recognized surgical procedure in this disease. The incidence of bilateral epididymo-orchitis in those who had this complication was 10.6 percent so that orchidotomy was useful generally for relief of pain rather than to prevent complete sterilization.

Because of the high incidence (approximating 30 percent) of this complication in widespread outbreaks on Army posts, it seemed appropriate for the Commission on Measles and Mumps to determine the possible protective value of ordinary immune serum globulin (gamma globulin) as prepared by the method of Cohn, Oncley, and others 15 against epididymo-orchitis after parotitis had started. This study was carried out at Fort Benning, Ga., by

13 Smith, G. G.: Two Cases of Orchitis Due to Mumps Treated by Operation. Boston M. & S. J. 167: 323-325, September 1912.

14Wesselhoeft, C., and Vose, S. :V.: Surgical Treatment of Severe Orchitis in Mumps. Now England J. Med. 227: 277-280, 20 Aug. 1942.

15Cohn, E. J., Oncley, J. L., Strong, L. E., Hughes, W. L., Jr., and Armstrong, S. H., Jr.: Chemical, Clinical, and Immunological Studies on the Products of Human Plasma Fractionation. 1. The Characterization of the Protein Fractions of Human Plasma.J. Clin. Investigation 23: 417-432, July 1944.


Gellis, McGuinness, and Peters.16 Within the first 24 hours of onset, 50 ml. of the globulin were injected intramuscularly in alternate admissions for mumps--67 men being injected, while 67 remained as controls. The incidence of orchitis in those injected was 20.9 percent, while in the controls it was 26.8 percent. This could not be considered a significant difference.

Gamma globulin was then obtained from the fractionation of convalescent mumps serum and injected in doses of 20 ml. into alternate cases as previously indicated--51 being injected within the first 24 hours after onset, while 51 remained as controls. The incidence of orchitis in the injected group was significantly lowered, apparently by the convalescent globulin, being 7.8 percent as compared with an incidence of 27.4 percent in the controls. In view of the fact that a figure of 7.8 percent was an exceptionally low figure for orchitis in mumps in any extensive Army outbreak, and inasmuch as the incidence in the control group corresponded well with the usual figure found in such outbreaks-approximately one-third of all cases of mumps in young adult males--the study proved to be highly suggestive. Thus, the gamma globulin from convalescent serum may well be worthy of further trial when mumps is active in recruitment centers or Army posts.

Annual rates for mumps in the continental United States were strikingly higher in World War I than in World War II. In 1918, the rate reached a high point of 75.5; the high point for the World War II period, on the other hand, was only 6.9, reached in 1943. The difference in rate has been regarded with apparent justification as evidence of the greater opportunities of rural youth for urban contact and of the actual decrease in the rural population during the intervening period between the two wars. The case fatality ratio for mumps was negligible-rarely was a death attributable to meningoencephalitis.

The Alaskan Department had the highest rate for mumps during the war period; this could be accounted for by the unusual amount of contact in inclosed places because of prolonged cold weather. On the other hand, in the Mediterranean theater, where the rates for most communicable diseases were high, the rate for mumps was inexplicably low. Thus, mumps in World War II continued to be a disease which was not completely predictable.

There continued to be certain Army posts in which commanding officers imposed working quarantine in attempts to control the spread of mumps. Aside from interfering with training activities and with the morale of the men, it had little effect.

16 Gellis, S. S., McGuinness, A. C., and Peters, M.: A Study on the Prevention of Mumps Orchitis by Gamma Globulin. Am. J. M. Sc. 210: 661-664, November 1945.