LE JOURNAL CANADIEN DES SCIENCES NEUROLOGIQUES

An Unusual Occurrence of Multiple Sclerosis in a Small Rural Community

THOMAS JOHN MURRAY

SUMMARY: Ten patients with multiple and 1952 during a polio out­ One of the most intriguing and sclerosis were found to have lived in break. The relationship of polio to puzzling aspects of multiple close proximity in a Nova Scotia multiple sclerosis bears further study. sclerosis is its unusual distribution in farming community of 150 people. All The average age of the patients when the world. There have been many had drunk unpasteurized milk as chil­ they had measles was 11.8 years. Evi­ studies to determine whether areas dren, were teetotallers, ate a high animal dence suggests a link between risk of fat diet, and were well educated. Of multiple sclerosis and both late onset of within this distribution have an un­ greater interest was the observation that measles and pubertal age. Late onset of usual prevalence or incidence, but six of the ten cases were related in two measles may be important in this cluster. only a few community clusters have family groups. Further epidemiological studies are been described. Such cluster studies The only time all patients lived in the needed to examine the age of onset of are of great interest in the search for community at the same time was in 1951 measles in M.S. cases. information, not just to explain the local phenomenon, but possibly to provide some etiological clues to the problem of multiple sclerosis in gen­ RESUME: Nous avons trouve 10 pa­ La relation entre la polio et la sclerose eral. tients atteints de sclerose en plaques en plaques demande une etude plus We studied 10 cases of multiple ayant vecu a proximite d'un village de poussee. sclerosis, all within a few miles of fermiers de 150 personnes en Nouvelle- L'age moyen des patients quand Us Ecosse. Tous ont bu du lait non- ont eu la rougeole etait de 11.8 ans. Ceci each other in a farming area of 150 pasteurise quand Us etaient enfants, pourrait indiquer un lien entre le risque people. fit rent bien eduques, s'abstenaient de sclerose en plaques et le debut tardif d'alcool et consommaient line diete de la rougeole et de la puberte. Le debut Community Study riche en gras animal. L'observation la tardif de la rougeole peut, en effet, etre The area under study is located in plus interessante etait que six des dix cas important dans le group que nous avons Colchester County, Nova Scotia. etaient relies a I'interieur de 2 groupes decrit. Des etudes epidemiologiques plus The nearest town is Tatamagouche, familiaux. poussees sont necessaires pour evaluer about eight miles away. The region Le seul temps oil tous les patients I'age de debut de la rougeole dans un is made up of three small farming vecurent dans le village en meme temps plus grand nombre de cas de sclerose en areas known as Balfron, Balmoral fut en 1951 et 1952 pendant les premieres plaques. Mills, and The Falls, all within three manifestations d'une epidemie de polio. square miles. A house-to-house count of the area showed that there were 27 active farms with 150 people living on them. Through community contacts we learned of 14 possible cases of M.S. in the region; examination showed 10 cases of M.S., two siblings with muscular dystrophy, one case of amyotrophic lateral sclerosis and one untreated myasthenia gravis. All the 10 M.S. patients lived or had previously lived in or around the Reprint requests to: Dr. T. J. Murray, Chief of area of The Falls. Over a three-year Medicine, Camp Hill Hospital, Halifax, Nova period, we attempted to explain this Scotia B3H 3G2. cluster by evaluating data from in­ Presented to The Royal College of Physicians and terviews and examination of pa­ Surgeons of Canada, Winnipeg, Manitoba, January, 1975. tients, on site visits, questionnaires

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and examination of all available re­ is related to the pubertal age group years, but examination showed that cords. (Poskanzer, 1968). We suggest that she had longstanding, untreated the age of onset of measles be myasthenia gravis. The relationship Possible Etiological Factors: evaluated in further epidemiological of these diseases has been reported Various findings emerged from studies of M.S. as a possible addi­ recently (Aita et al., 1974). our study. During their childhoods tional clue to the cause of the dis­ When the life patterns of these there were animals in and around the ease. Perhaps the age at which one patients were plotted with particular homes and farms of all patients. All contracts a viral infection is more attention to when they lived in and drank unpasteurized milk as chil­ important than the specific agent it­ around the area of The Falls, we dren. All were teetotallers. The edu­ self. found that the only time all patients cational level of the patients was The animal fat intake in the pa­ lived in the same vicinity at the same high. All ate a high animal fat diet tients' diets is high, but an estimated time was during 1951 and 1952. It with over 800 mg of cholesterol per average consumption of 800 mg/day was thus of some interest that there day. The average age of measles was of cholesterol is not unusual for a was an outbreak of polio in 1952 in 11.8 years. Six of the 10 cases were North American diet (Guthrie, the area of Tatamagouche, which related in two families. The only 1975). We also found similar dietary includes the region under study years that all patients lived in the patterns among 16 multiple sclerosis (Peart et al., 1953). In that commun­ same vicinity at the same time were patients in the Halifax area where ity of 628 people, there were 12 1951 and 1952, and in 1952 there was the prevalence rate of M.S. is 21 per paralytic polio cases or 1.9% of the a major polio outbreak in the region. 100,000 population. Alter (1975) has population, and 47% of the popula­ suggested that experimental and tion had a "polio-like" illness. Eight clinical observations relating diet to of the 10 M.S. patients developed DISCUSSION increased adhesiveness of formed their disease in the years following The presence of animals around blood elements, biochemical altera­ this epidemic and none remembered homes, and the drinking of unpas­ tions of central myelin, and impaired being ill during it. The evidence for a teurized milk in childhood would not delayed hypersensitivity are plausi­ definite relationship to the polio be surprising in a farming commun­ ble mechanisms linking the risk of epidemic in 1952 is not strong, but an ity 25 years ago. Although we were M.S. to high animal fat consump­ association of M.S. with polio has surprised to find that all patients tion. Accurate determinations of been made in the past by Poskanzer were teetotallers, this and the fact cholesterol intake by history, espe­ (1963), who noted that the diseases that only one of them smoked could cially in attempts to determine diet­ have similar epidemiological, geo­ be due to the prevalent Scottish ary habits in earlier life, are so un­ graphical, social, and familial pat­ Presbyterian background. The edu­ certain that we can obtain only a terns. More recently it was found cational level of the patients seemed rough and unreliable estimate of in­ that polio victims, like M.S. pa­ very high. Some were school­ take. Also, virtually all M.S. pa­ tients, have increased HL-A 3 and teachers, several had university de­ tients alter their diet in some way HL-A 7 antigens, again suggesting grees, one is an accountant, and one after they develop the disease and it similar etiological mechanisms is an emeritus university professor. becomes even more difficult to ob­ (Morris and Pietsch, 1973). This might also be explained by the tain information on what their previ­ Personal contact among patients Scottish background of the patients, ous diet had been. (except for those related to each since the Scots have always placed a Family relationships are important other), travel, surgery, (including high premium on education. in this cluster study as six of the 10 tonsillectomy), and the use of drugs The average age of the patients cases are related in two families. In and patent medications in earlier life when they had measles was 11.8 the first, a brother and sister both could not be definitely related to the years. This is unusually late; most have multiple sclerosis. These sib­ high number of M.S. cases. Al­ children have had measles at school lings are of some interest because, though many of the patients had entry age. Perhaps the rural isolation although their families moved away Scottish origins, the families had accounts for the late age for measles, from The Falls many years ago, both come to the area at least 150 years but it is of interest that Alter (1975) children who later developed multi­ ago from various parts of Scotland. recently noted a generally late onset ple sclerosis continued to spend There did not appear to be anything of measles in M.S. patients. The summers in The Falls. However, a unusual about the course of the dis­ occurrence of measles around the first cousin who has never lived in ease or disability rating and pattern time of puberty is of some interest The Falls also had multiple of clinical involvement by the since there is increasing evidence sclerosis. In the second family, there Kurtzke scale (Kurtzke, 1963). that measles is related to the de­ are two sisters with multiple velopment of multiple sclerosis in sclerosis and a nephew with a Other Community Studies: some way (Haire et al., 1973 and rapidly progressive form of M.S. It Probably the best known cluster Haire et al., 1974). There is also is of interest that this boy's mother of M.S. was that reported by Camp­ evidence that whatever the risk fac­ was thought by the family and com­ bell et al. (1947) involving four cases tor or agent is in multiple sclerosis it munity to have had M.S. for many in seven men working on swayback

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disease. Campbell et al. (1950) cases in certain villages along rivers nately, whether the clusters reported studied lead in relation to M.S. in a suggested an exogenous factor in the in M.S. occur by chance cannot be number of counties in England and water, but because the clustering evaluated statistically and such found six cases within 500 yards of was greater by birthplace than by studies are prone to bias. However, each other in a small village in Berk­ domicile they also suspected some the reason for reporting such events shire. They also found three cases in hereditary factor in the etiology of is not to prove whether they might another village and subsequently the disease. Their study revealed occur by chance or not, but to possi­ two further cases in the same that the birthplaces of parents were bly point to factors that may be county. They attributed the high in­ strikingly concentrated in neighbor­ important in the etiology of M.S. and cidence of M.S. in this area to the ing villages in the same clerical dis­ which could be evaluated in larger high lead content in the soil and trict. In a subsequent study, Wik­ epidemiological studies. It is in this water. strom examined the increased inci­ spirit that the present community Sutherland (1956) mentions the dence of tuberculosis in the same study is reported. occurrence of M.S. in three areas of Finland that had increased girlfriends, three neighbors in the prevalence of M.S. and concluded same street, and two gamekeepers that perhaps there was a common who lived in succession in the same genetic factor for tuberculosis and REFERENCES house. In 1959 eight cases of M.S. M.S. (Wikstrom, 1975). AITA, J. F., SNYDER. D. H. and REICHL. were found in Duxbury, Mas­ W. (1974). 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