Letters to the Editor
482
Following general tuition in the environmental health aspects of Public Health Medicine but before any teaching on specific topics such as recreational exposure to polluted water, all of the 15 aspects were mentioned by more students than before the tuition; seven aspects instead of two before were mentioned by more than 50% of students; 14 aspects instead of eight before were mentioned by more than 30% of students, and for five of the 15 aspects there was an increase of 30% or greater in group awareness after the teaching as compared with before it. Staff have welcomed but are not complacent about these levels of student achievement. They do though, provide further evidence that PMQs can be readily developed and that, with their use before and after the teaching, beneficial changes in acquired learning and its application can be identified. When Table I was given as feedback to students and staff, it was welcomed as a basis for further discussion about the different professional responsibilities and needs that are being debated for problem-based learning and fostering of closer links between epidemiology, clinical practice and environmental protection.2
ROBIN PHILIPP, Department of Epidemiology and Public Health Medicine, University of Bristol References
1. Philipp, R. (199:2). Problem-management questionnaires as a student learning tool in environmental medicine. Public Health, 106,289-299. 2. Philipp, R. (1990). Environmental health training within Public Health Medicine. Public
Health, 104,465-471.
Dear Sir, Could Contact with S e a w e e d Cause Skin Blisters?
I did a pilot case control study in south-east Kent, the findings of which may be of interest to your readers. In the summer of 1991 in south-east Kent there were reports in the local newspapers of the occurrence of skin blisters associated with a visit to local beaches in Dover, Folkestone, Hythe and Dymchurch. These newspaper reports were followed by complaints of the same nature to the Environmental Health Department of the Shepway District Council. T h e r e were also suggestions that either swimming in the sea or coming into contact with seaweed could have caused these problems. Initial investigations suggested that some people who had been to the sea beaches during holiday periods had developed skin blistering a day or two after the visit. A pilot case control study was undertaken to test the hypothesis that this occurrence of skin blistering was associated with visits to the sea beaches and was caused by either swimming and/or contact with seaweeds. A case was defined as a person with a self-reported episode of blistering of the skin occurring during the months of July, August or September 1991 and who was at this time resident in the South East Kent District Health Authority. Everybody who reported such skin complaints to the local papers and all the cases who made complaints to the local authority with this condition were included as cases. Ten cases
483
Letters to the Editor
were identified in this manner. A general letter was sent to all the general practitioners in south-east Kent requesting t h e m to inform the Consultant in Communicable Disease Control of cases of skin blistering they had seen during this period. Three cases were notified as a result of these letters, out of which only one was found to have been true skin blistering. T h e other two had generalised skin rashes. The eleven cases thus identified were interviewed by the Environmental Health Officers ( E H O s ) f r o m Ashford Borough, D o v e r District and Shepway District Councils. A standard questionnaire was used by the interviewer and answers to questions regarding water sports, pets, visits to beaches, activities on the beach, symptoms, etc, were obtained. Each case was then requested at the interview to n a m e three friends of the same age and sex. T h e E H O s then proceeded to find these persons and interviewed as m a n y as they could using the same questionnaire. A further 21 people were interviewed as the E H O s on average interviewed two contacts for each case. Out of these 21, five people fulfilled the criteria of the case definition and were classed as cases. The remaining 16 people were used as controls in the analysis. The age distribution of the cases and controls was similar except there were 11 controls c o m p a r e d with seven cases in the under-9 age group. The sex distribution was also similar in both the groups. Clinical presentation of the cases was characteristic with skin blisters occurring in 100% of cases mostly on the leg (50%) and hand (50%). A r m s (38%), feet (25%) and trunk (25%) were also affected. In a few cases peeling of the skin (19%) and rash (13%) occurred. For those p e o p l e who visited the beaches the association between different exposures and skin blistering was not statistically significant except for contact with seaweed (Table I). The odds ratio was 14 for seaweed while those for other exposures were all less than 3 - - m o s t l y under 1. The 95% confidence interval was between 1.02
Table
1 Exposure of cases and controls for those who visited the beach Cases
Swam in sea Paddled in water Lay on sand Paddled or played in rock pool Contact with jelly fish Contact with seaweed Contact with oil Contact with empty containers
Controls
Odds ratio
95% Fisher's Sig./not confidence exact test sig. interval
Did
Didn't
Did
Didn't
11 13
4 2
6 7
4 3
1.83 2.79
0.24-14.40 0.27-33.23
0.7 0.4
NS NS
11 2
4 13
9 3
1 7
0.31 0.36
0.01-4.12 0.03-3.76
0.6 0.1
NS NS
14
0
10
-
-
1.0
NS
1
14
1
5
5
14.00
1.02-418.68
0.02
S
2
13
3
7
0.36
0.03-3.76
0.4
NS
1
14
3
7
0.17
0.01-2.50
0.3
NS
484
Letters to the Editor
and 418.68. Fisher's exact test for the association between cases and contact with seaweed resulted in a two-tailed P value of < 0.05 (0.02). This was a pilot study on a small number of cases. Only nine of the 16 cases visited general practitioners, indicating that there may have been more cases who never consulted a professional. Case finding was extremely difficult, as general practitioners, although some provided cases, had not seen very many cases in total. The other sources available were the media and the direct complaints to the Environmental Health Department. The risk of swimming in heavily polluted water remains undisputed and carries with it the risk of contracting infections such as typhoid, shigellosis, leptospirosis and hepatitis A.~ One of the first studies to show a relation between sea bathing and minor symptoms was a prospective cohort study carried out in 1970 by the United States Environmental Protection Agency, which showed a relation between swimming, gastro-intestinal symptoms and the quality of the sea water. 2 Dr Pike's studies at Langland Bay in West Glamorgan showed a higher incidence of ear and throat symptoms among those who went to the sea. 3 Balarajan et al. 4 in their study at the main beach in Ramsgate, Kent reported an increased and dose-related risk of self-reported illness from bathing in sea water. Bathers experienced significantly more gastro-intestinal illness than non-bathers. The risk of diarrhoea was almost doubled. Relative risks were also raised for eyes, ear, nose, throat and respiratory symptoms, although they did not reach significance. The study in Ramsgate differed from the study at Langland Bay in that at Ramsgate, there was a significant association between bathing and gastro-intestinal symptoms. Findings in Ramsgate also showed higher levels of faecal pollution where there were failures of the E C mandatory thermotolerant coliform standard on 12% of sampling occasions. 5 Although there is reasonable evidence available from previous studies to show an association between gastro-intestinal and other illnesses and sea bathing in polluted water, so far no evidence has been available to show an association between sea bathing and skin blistering. This pilot study has shown a statistically significant association between skin blistering and contact with seaweeds for those people who visited the sea beach. One of the disadvantages of this study is the fact that the numbers are small, hence interpretation is extremely difficult. A further study is needed to test this hypothesis. As a result of this study we intend to monitor the incidences of skin blistering and other illness following visits to sea beaches in the summers of 1992 and 1993. We also intend to encourage general practitioners to report these incidences to the Consultant in Communicable Disease Control. A prospective cohort study is being considered in the summer of 1993 with a larger number of holiday-makers.
M. CHANDRAKUMAR MBBS FRCS ED M F P H M , Consultant in Public Health Medicine/Communicable Disease Control, Department of Public Health Medicine, South East Kent Health Authority, 'Ash-Eton', Randor Park West, Folkestone, Kent CT19 5HL
Letters to the Editor
485
References
1. Walker, A. (1992). Swimming--the hazards of taking a dip. British Medical Journal, 304, 242-245. 2. Cabelli, V. J., Dufour, A. P., McCabe, L. J. & Levin, M. A. (1982). Swimming--associated gastroenteritis and water quality. American Journal of Epidemiology, 115,606-616. 3. Pike, E. B. (1990). Phase 1 pilot study at Langland Bay. (Department of Environment report 2518-M (P)). London: Water Research Centre/HMSO. 4. Balarajan, R., Raleigh, V. S., Yues, P., Wheeler, D., Machin, D, & Cartwright, R. (1991). Health risks associated with bathing in sea water. British Medical Journal, 303, 144-145. 5. Epidemiology and Public Health Research Unit (1990). Health Risks Associated with Bathing in the Sea; Results of a Study in Ramsgate. Guilford: University of Surrey.
482
Following general tuition in the environmental health aspects of Public Health Medicine but before any teaching on specific topics such as recreational exposure to polluted water, all of the 15 aspects were mentioned by more students than before the tuition; seven aspects instead of two before were mentioned by more than 50% of students; 14 aspects instead of eight before were mentioned by more than 30% of students, and for five of the 15 aspects there was an increase of 30% or greater in group awareness after the teaching as compared with before it. Staff have welcomed but are not complacent about these levels of student achievement. They do though, provide further evidence that PMQs can be readily developed and that, with their use before and after the teaching, beneficial changes in acquired learning and its application can be identified. When Table I was given as feedback to students and staff, it was welcomed as a basis for further discussion about the different professional responsibilities and needs that are being debated for problem-based learning and fostering of closer links between epidemiology, clinical practice and environmental protection.2
ROBIN PHILIPP, Department of Epidemiology and Public Health Medicine, University of Bristol References
1. Philipp, R. (199:2). Problem-management questionnaires as a student learning tool in environmental medicine. Public Health, 106,289-299. 2. Philipp, R. (1990). Environmental health training within Public Health Medicine. Public
Health, 104,465-471.
Dear Sir, Could Contact with S e a w e e d Cause Skin Blisters?
I did a pilot case control study in south-east Kent, the findings of which may be of interest to your readers. In the summer of 1991 in south-east Kent there were reports in the local newspapers of the occurrence of skin blisters associated with a visit to local beaches in Dover, Folkestone, Hythe and Dymchurch. These newspaper reports were followed by complaints of the same nature to the Environmental Health Department of the Shepway District Council. T h e r e were also suggestions that either swimming in the sea or coming into contact with seaweed could have caused these problems. Initial investigations suggested that some people who had been to the sea beaches during holiday periods had developed skin blistering a day or two after the visit. A pilot case control study was undertaken to test the hypothesis that this occurrence of skin blistering was associated with visits to the sea beaches and was caused by either swimming and/or contact with seaweeds. A case was defined as a person with a self-reported episode of blistering of the skin occurring during the months of July, August or September 1991 and who was at this time resident in the South East Kent District Health Authority. Everybody who reported such skin complaints to the local papers and all the cases who made complaints to the local authority with this condition were included as cases. Ten cases
483
Letters to the Editor
were identified in this manner. A general letter was sent to all the general practitioners in south-east Kent requesting t h e m to inform the Consultant in Communicable Disease Control of cases of skin blistering they had seen during this period. Three cases were notified as a result of these letters, out of which only one was found to have been true skin blistering. T h e other two had generalised skin rashes. The eleven cases thus identified were interviewed by the Environmental Health Officers ( E H O s ) f r o m Ashford Borough, D o v e r District and Shepway District Councils. A standard questionnaire was used by the interviewer and answers to questions regarding water sports, pets, visits to beaches, activities on the beach, symptoms, etc, were obtained. Each case was then requested at the interview to n a m e three friends of the same age and sex. T h e E H O s then proceeded to find these persons and interviewed as m a n y as they could using the same questionnaire. A further 21 people were interviewed as the E H O s on average interviewed two contacts for each case. Out of these 21, five people fulfilled the criteria of the case definition and were classed as cases. The remaining 16 people were used as controls in the analysis. The age distribution of the cases and controls was similar except there were 11 controls c o m p a r e d with seven cases in the under-9 age group. The sex distribution was also similar in both the groups. Clinical presentation of the cases was characteristic with skin blisters occurring in 100% of cases mostly on the leg (50%) and hand (50%). A r m s (38%), feet (25%) and trunk (25%) were also affected. In a few cases peeling of the skin (19%) and rash (13%) occurred. For those p e o p l e who visited the beaches the association between different exposures and skin blistering was not statistically significant except for contact with seaweed (Table I). The odds ratio was 14 for seaweed while those for other exposures were all less than 3 - - m o s t l y under 1. The 95% confidence interval was between 1.02
Table
1 Exposure of cases and controls for those who visited the beach Cases
Swam in sea Paddled in water Lay on sand Paddled or played in rock pool Contact with jelly fish Contact with seaweed Contact with oil Contact with empty containers
Controls
Odds ratio
95% Fisher's Sig./not confidence exact test sig. interval
Did
Didn't
Did
Didn't
11 13
4 2
6 7
4 3
1.83 2.79
0.24-14.40 0.27-33.23
0.7 0.4
NS NS
11 2
4 13
9 3
1 7
0.31 0.36
0.01-4.12 0.03-3.76
0.6 0.1
NS NS
14
0
10
-
-
1.0
NS
1
14
1
5
5
14.00
1.02-418.68
0.02
S
2
13
3
7
0.36
0.03-3.76
0.4
NS
1
14
3
7
0.17
0.01-2.50
0.3
NS
484
Letters to the Editor
and 418.68. Fisher's exact test for the association between cases and contact with seaweed resulted in a two-tailed P value of < 0.05 (0.02). This was a pilot study on a small number of cases. Only nine of the 16 cases visited general practitioners, indicating that there may have been more cases who never consulted a professional. Case finding was extremely difficult, as general practitioners, although some provided cases, had not seen very many cases in total. The other sources available were the media and the direct complaints to the Environmental Health Department. The risk of swimming in heavily polluted water remains undisputed and carries with it the risk of contracting infections such as typhoid, shigellosis, leptospirosis and hepatitis A.~ One of the first studies to show a relation between sea bathing and minor symptoms was a prospective cohort study carried out in 1970 by the United States Environmental Protection Agency, which showed a relation between swimming, gastro-intestinal symptoms and the quality of the sea water. 2 Dr Pike's studies at Langland Bay in West Glamorgan showed a higher incidence of ear and throat symptoms among those who went to the sea. 3 Balarajan et al. 4 in their study at the main beach in Ramsgate, Kent reported an increased and dose-related risk of self-reported illness from bathing in sea water. Bathers experienced significantly more gastro-intestinal illness than non-bathers. The risk of diarrhoea was almost doubled. Relative risks were also raised for eyes, ear, nose, throat and respiratory symptoms, although they did not reach significance. The study in Ramsgate differed from the study at Langland Bay in that at Ramsgate, there was a significant association between bathing and gastro-intestinal symptoms. Findings in Ramsgate also showed higher levels of faecal pollution where there were failures of the E C mandatory thermotolerant coliform standard on 12% of sampling occasions. 5 Although there is reasonable evidence available from previous studies to show an association between gastro-intestinal and other illnesses and sea bathing in polluted water, so far no evidence has been available to show an association between sea bathing and skin blistering. This pilot study has shown a statistically significant association between skin blistering and contact with seaweeds for those people who visited the sea beach. One of the disadvantages of this study is the fact that the numbers are small, hence interpretation is extremely difficult. A further study is needed to test this hypothesis. As a result of this study we intend to monitor the incidences of skin blistering and other illness following visits to sea beaches in the summers of 1992 and 1993. We also intend to encourage general practitioners to report these incidences to the Consultant in Communicable Disease Control. A prospective cohort study is being considered in the summer of 1993 with a larger number of holiday-makers.
M. CHANDRAKUMAR MBBS FRCS ED M F P H M , Consultant in Public Health Medicine/Communicable Disease Control, Department of Public Health Medicine, South East Kent Health Authority, 'Ash-Eton', Randor Park West, Folkestone, Kent CT19 5HL
Letters to the Editor
485
References
1. Walker, A. (1992). Swimming--the hazards of taking a dip. British Medical Journal, 304, 242-245. 2. Cabelli, V. J., Dufour, A. P., McCabe, L. J. & Levin, M. A. (1982). Swimming--associated gastroenteritis and water quality. American Journal of Epidemiology, 115,606-616. 3. Pike, E. B. (1990). Phase 1 pilot study at Langland Bay. (Department of Environment report 2518-M (P)). London: Water Research Centre/HMSO. 4. Balarajan, R., Raleigh, V. S., Yues, P., Wheeler, D., Machin, D, & Cartwright, R. (1991). Health risks associated with bathing in sea water. British Medical Journal, 303, 144-145. 5. Epidemiology and Public Health Research Unit (1990). Health Risks Associated with Bathing in the Sea; Results of a Study in Ramsgate. Guilford: University of Surrey.
