GIARDIASIS AN UNUSUAL CAUSE OF EPIDEMIC DIARRHŒA

615

rhoea, especially in the absence of a bacterial and if there is a history of foreign travel.

Public Health

cause

INTRODUCTION

Giardia lamblia

GIARDIASIS AN UNUSUAL CAUSE OF EPIDEMIC DIARRHŒA

D. S. KARANDIKAR LEEK J. Public Health Laboratory, New Cross Hospital, Wolverhampton, and County Borough of Walsall Health R. G. THOMPSON

after

Mediterranean cruise.

June, 1973, party of about 1300 healthy people consisting mainly of Midlands and Southampton schoolchildren aged 10-12 years went on a cruise in the Western a

Mediterranean.

An outbreak of giardiasis in children and adults after a Mediterranean cruise is described. 136 people from the Walsall and

Wolverhampton area were investigated and 70% were infected; 55% had symptoms, mainly diarrhœa and abdominal pain. Treatment with mepacrine or metronidazole was highly effective. Similar experirecorded from other areas. The outbreak to be water-borne, probably acquired at a port of call. It is recommended that the diagnosis of giardiasis be considered in cases of persistent diar-

ences are

1.

produce diarrhoeal disease, and,

REPORT

Summary

2.

a

In

Department, Walsall, Staffordshire

was

can

though most cases of infestation are sporadic, occasionally epidemic disease may occur (e.g., in a nurseryor in travellers -7). We report here an episode

thought

Jelliffe, D. B. W.H.O. Monogr. Ser. 1966, no. 53. Béhar, M. in Malnutrition, Learning and Behavior (edited by N. S. Scrimshaw, and J. E. Gordon); p. 30. Cambridge, Massachusetts,

1968. 3. Guzmán, M. A. ibid. p. 42. 4. National Academy of Sciences-National Research Council. PreSchool Child Malnutrition: Primary deterrent to human progress. Washington, D.C., 1966. 5. Garn, S. M., Am. J. clin. Nutr. 1962 11, 418. 6. Garn, S. M. Can. med. Ass. J. 1965, 93, 914. 7. Nelson, W. E. (editor) Textbook of Pediatrics. Philadelphia, 1964. 8. Hansman, C. in Human Growth and Development (edited by R. W. McCammon); p. 101. Springfield, Illinois, 1970. 9. Tanner, J. M., Whitehouse, R. H., Takaishi, M. Archs Dis. Childh. 1966, 41, 454, 613. 10. Roche, A. F., Cahn, A. Med. J. Aust. 1962, i, 595. 11. Verghese, K. P., Scott, R. B., Teixeira, G., Ferguson, A. D. Pediatrics, 1969, 44, 243. 12. Terada, H., Hoshi, H. Acta anar. Nippon, 1965, 40, 166. 13. Swaminathan, M. C., Jyothi, K. K., Singh, R., Madhavan, S., Gopalan, C. Indian Pœdiat. 1964, 1, 255. 14. Shrivastva, A. K., Taluja, R. K., Kaur, K. K. ibid. 1970, 7, 313. 15. Currimbhoy, Z. Indian J. Child. Hlth, 1963, 12, 627. 16. Luna-Jaspe, G. H., Ariza Macias, J., Rueda-Williamson, R., Mora Parra, J. O., Pardo Tellez, F. Archs latino-am. Nutr. 1970, 20, 151. 17. Smith, B. J., Hauck, H. M. J. trop. Pediat. 1961, 7, 55. 18. Morley, D. C., Woodland, M., Martin, W. J., Allen, I. West Afr. med. J. 1968, 17, 8. 19. Mata, L. J., Urrutia, J. J., Cáceres, A., Guzmán, M. A. in Proceedings of IIIrd Western Hemisphere Nutrition Congress (edited by P. L. White); p. 257. New York, 1972; and unpublished. 20. Yarbrough, C., Habicht, J.-P., Malina, R. M., Lechtig, A., Klein, R. E. Unpublished. 21. Krogman. W. M. Monogr. Soc. Res. Child Devel. 1950, 13, no. 3. 22. Barja, I., De la Fuente, M. E., Ballester, D., Mönckeberg, F., Donoso, G. Revta. chil. Pediat. 1965, 36, 525. 23. Udani, P. M. Indian J. Child. Hlth, 1963, 12, 593. 24. Eksmyr, R. Acta pœdiat. scand. 1970, 59, 157. 25. Rea, J. N. Human Biol. 1971, 43, 46. 26. Dean, R. F. A. Courrier, 1965, 15, 73. 27. Jose, D. G., Welch, J. S. Med. J. Aust. 1970, i, 349. 28. Scrimshaw, N. S., Taylor, C. E., Gordon, J. E. W.H.O. Monogr Ser. 1968, no. 57, p. 329. 29. Malina, R. M. Unpublished. 30. Hiernaux, J. Human Biol. 1964, 36, 273. 31. Jans, C. Ann. Soc. Belg. Med. Trop. 1959, 39, 851. 32. Vis, H. L., Yourassowsky, C., van der Borght, H. Une enquète de : consommation alimentaire en République Rwandaise. Institu t National de Récherche Scientifique, Butare, Rwanda, 1972. 33. Tanner, J. M., Israelsohn, W. Ann. hum. Genet. 1963, 26, 245. 34. Hoshi, H. Monogr. Soc. Res. Child Devel. 1970, 35, 49. ,

Many passengers complained of abdominal pain and diarrhoea towards the end of the voyage; Salmonella or Shigella organisms were not found. The diarrhoea persisted, causing significant weight-loss in some cases, despite symptomatic treatment; other passengers on returning home after the cruise began to be similarly affected. Sixteen days after the cruise party disembarked, the Health Department, Walsall, learned that a teacher was still having symptoms and had lost weight. She indicated that many other members from the school had the same type of illness. Again, no fsecal bacterial pathogens were found. After discounting a virus aetiology concentrated wet fsecal preparations8 were examined for G. lamblia. Seven out of ten stools on preliminary investigation were heavily infested with the cysts of G. lamblia, and this high frequency of infestation was confirmed in other passengers. By this time all passengers were now at home, and so it was decided to inform public-health departments, the Public Health Laboratory Service, and the Department of Health. Cysts of G. lamblizz were found in 95 (70%) individuals of a party of 125 children and 11 teachers from various schools in Walsall and Wolverhampton; there was no significant sex difference. 52 (55%) of those infested had symptoms, diarrhoea being the most frequent (71%); colicky abdominal pain or discomfort was present in 56% and vomiting in 33%. Anorexia, nausea, headache, fever, and lethargy were less frequent symptoms, and none had blood in their stools. Illness, severest in adults, varied from mild disablement to persistent incapacitating diarrhoea with accompanying weight-loss of up to 4’5 kg.

(10 lb.). 30 patients were treated for five days with mepacrine and 65 with metronidazole (’ Flagyl’). The clinical response was rapid, most cases becoming symptomless after two or three days. Only 4 of the 95 patients still had cysts after treatment. Three of the treatment failures occurred after metronidazole and 1 after mepacrine; in these cases a repeat course of metronidazole resulted in disappearance of cysts from the stools. There was no difference in therapeutic efficacy for either drug. Temporary yellow discolouration of the skin occurred, as expected, in 4 of the patients given mepacrine; 2 patients treated with metronidazole complained of nausea and vomiting. No secondary person-to-person spread was found. There were similar findings in schoolchildren that had been on the cruise, in other areas. Thus of a group of 42 children and 6 teachers from Swinton, near Manchester, 29 children and 1 teacher were infected. Main symptoms were recurrent diarrhoea and weight-loss; there was good response to metronidazole. 8 of 19 boys from Enfield, Middlesex, had giardial cysts in their faeces, and these were found in stools from a few symptomatic children in Boston, Lincolnshire, in 2 of 5 individuals in Plymouth, in

616 28 of 46

individuals, less severely affected clinically, in Southampton, and in faeces from 14 children and 2 teachers

of

a sample of Birmingham.

21 individuals with diarrhoea examined in

patient presenting with abdominal symptoms can be placed in a surgical unit, as happened in this outbreak.I5

mepacrine or metronidazole was judged by the rapid clinical rehighly effective, and sponse disappearance of cysts from the stool. Giardiasis is a relatively rare cause of epidemic diarrhoea, but, with increased travel abroad, episodes There may be wide are likely to be more frequent. individuals before the diagnosis of infected dispersion is made, since the incubation period varies (approximately one to four weeks) and clinical illness need Treatment with

passengers is limited to 1 case. A middle-aged woman from Birmingham had severe diarrhoea and abdominal pain, and, though cysts were not demonstrated in her stool at the time of examination, symptoms disappeared after a course of metronidazole. Presumably she was not excreting cysts at the time of

Information about the

private

testing. DISCUSSION

G. lamblia is a parasite of the duodenum and small intestine. Flagellate forms or, more commonly, cysts occur in the stool, and the resistant (cyst) phase permits infestation to pass between hosts. Man is the natural host and the only known reservoir. Surveys in various regions of the world have shown prevalences ranging from 1% to 30%, depending on the type of specimen examined, sample size, agegroup, and the level of enviromental hygiene. Infestation is especially common in children, in conditions associated with poor hygiene, and in institutions. In the past twenty-five years prevalence-rates of 10% or less have been reported in large surveys (over 1000 individuals) from various parts of the world.9 The prevalence of giardial cyst infestation in the United Kingdom is unknown, but is probably of this order. Infestation takes place by transmission of viable cysts via the faecal-oral route by person-to-person spread or by a common vehicle. Experimental studies 10 have shown that flies are inefficient transmitters of cysts. In two epidemics 2,4 a water-borne mechanism was postulated. We are uncertain of the source of this outbreak, but consider that its explosive development is consistent with a common-source outbreak, water being the probable vehicle. The ship’s water supply could have been an agent of transmission, but this is unlikely since the crew were unaffected. Furthermore, microscopic examination of the residue of this supply after concentration failed to reveal cysts "; no new cases have been reported on subsequent cruises. Many affected children had drunk from a public water fountain at one port; others may have consumed the same supply locally. This water supply may have been the source of the outbreak. The presentation of this outbreak was similar to that described in other episodes. Characteristically symptoms began late and diarrhoea persisted. This is in sharp contrast to "travellers’ diarrhoea ", in which symptoms begin early in a journey and last for a few days. We found giardial cysts in 70% of individuals, of whom 55% had symptoms. Other workers have found this variable response to infection.’, 12 Knowledge of the host-parasite relationship is incomplete, and, whilst some host factors are known,13 those to the parasite are largely unknown, though invasion of intestinal mucosa has been demonstrated

relating

histologically." Giardiasis is not usually serious, although rarely death may result.1 The chronic unremitting diarrhoea may be severely disabling. Furthermore, a

as

not

result.

Management may depend on the numbers involved. In our area there were relatively few passengers, and all had their stools examined. All passengers with cysts were treated irrespective of the clinical state. However, where there were many passengers (e.g., Birmingham) it was considered more practicable and economic to treat only those with symptoms, once the diagnosis in a sample of affected individuals had been confirmed by the laboratory. Treatment relieves diarrhoea in the ill and reduces the risk of secondary spread, since it is reasonable to suppose that transmission is most likely from these cases; in addition the reservoir of infection is kept to a low level. In the laboratory investigation of diarrhoea with a probable bacterial cause, it is customary in the U.K. to attempt isolation of the likely pathogen by culture, microscopic examination of the stool being of secondary importance. However, such examination is mandatory in the diagnosis of giardiasis. We recommend that fxces should be examined microscopically in all cases of persistent diarrhaea where a pathogen has not been isolated, especially if there is a history of travel to the Mediterrranean region. We thank the following medical officers of health for allowus to record details of cases : Dr W. J. Elwood (Swinton), Dr G. Hird (Boston), Dr W. D. Hyde (Enfield), Dr W. Nicol (Birmingham), Dr T. A. 1. Rees (Plymouth), and Dr P. C. Walker (Wolverhampton), and the following members of the Public Health Laboratory Service: Dr J. D. Abbott (Manchester), Dr J. M. Graham (Southampton), Dr J. G. P. Hutchison (Birmingham), Dr P. D. Meers (Plymouth), Dr P. R. Mortimer (Whipps Cross), Dr M. J. Robertson (Birmingham), and Dr B. T. Thom (Brighton). We thank Mr D. Hough and Mrs L. Johnson of the Health Department, Walsall, for their assistance, and Dr I. A. Harper, Public Health Laboratory, Wolverhampton, for his continued interest and helpful criticism.

ing

Requests for reprints should be addressed

to

R. G. T.

REFERENCES 1. 2.

3. 4. 5.

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