Swimming in the lake – The lake is looking particularly gorgeous at the moment and many people are taking advantage of the hot weather and taking a dip in the water to cool off.
If you are one of those you might like to know that that there is a small publication called “Carte des Plages du Léman” produced by CIPEL (International Commission for the protection of Leman Waters) which has a map of all the beaches and places you can swim around the entire lake. It also lists the water quality around all of these beaches and you will be pleased to know that many of these fall into “good quality water” category, a few fall into the “average quality” mark and only one beach (on the French side) out of a total of 116 around the entire lake falls into “bad quality” and where you cannot swim.
However if you do decide to go for a swim you do need to be aware of the problem of duck fleas. Below is an approximate translation from the publication as to what these are and if you catch them what to do about it. Living in Nyon is delighted that Dr Michelle Wright has helped with this translation and added some other advice of her own.
Dr Wright is an English speaking doctor, a General Practitioner, who works part-time for one of the United Nations Organisations in Geneva. She also works as a medical writer and has a weekly programme on WRS called “Health Matters”. As well as this, Dr Wright provides First Aid and Cardio-Pulmonary Resuscitation courses in English through HealthFirst (website under construction).
She can be contacted on the email firstname.lastname@example.org
Here is the translation from the leaflet from CIPEL
“The beaches around Lac Leman are practically all favourable for swimming. 50 metres from the edge, the water is of good quality to swim in, however it is not safe to drink. Even on an extremely clean beach, there may be a risk of ‘swimmers dermatitis’ or ‘duck fleas’, especially in shallow waters which are rich in vegetation and where the temperature is over 20 degrees centigrade. This is a natural phenomenon and bears no relation to pollution.
This dermatological problem is caused by the larvae of a duck parasite that penetrate human skin and cause intense itching. Fortunately it is not dangerous. To avoid ‘swimmers dermatitis’, it is recommended to take a shower immediately after swimming and to dry yourself off vigorously with a towel afterwards. It is also advisable to avoid swimming close to the plants and vegetation near to the water’s edge.
If you do get a rash, you should avoid scratching it in order to prevent secondary bacterial infection. The rash should disappear without any traces within 10-20 days.”
Dr Michelle Wright also adds
What are ‘duck fleas’?
‘Duck fleas’ (‘puces de canard’ in French) are actually a relatively common problem that can result from swimming in Lac Leman. They can lead to an itchy skin rash known as ‘swimmers itch’ or ‘swimmers dermatitis’. Swimmer’s itch is not caused by fleas exactly but by a worm-like parasite whose usual host is the ducks that live in the lake. Whilst you are swimming in the lake, immature forms of the parasite larvae can penetrate ‘mistakenly’ through your skin rather than finding their usual host, a duck. So, humans are infected ‘accidentally’. The parasite actually dies when it enters your skin. However, your body develops an allergic reaction to the parasite and it is this that causes the rash.
What are the symptoms?
On your first exposure to the parasite, you may not have any reaction or develop any symptoms. However, you can still become ‘sensitized’ to the parasite and the next time that you are exposed to it, symptoms can develop.
If symptoms do develop, at first you may notice tiny red spots at the points at which the larvae have penetrated your skin. The spots can be tingly or itchy. After a few hours, the spots tend to become bigger and more ‘pimple-like’ or bumpy. Intense itching is usual at this stage. Occasionally, blistering can occur over the next few days. The rash will develop on areas of the skin exposed to the water. So, skin under a swimsuit can be protected and therefore spared from the rash.
If you have developed swimmer’s itch before, you may develop a more severe rash the next time you are exposed to the parasite.
What treatment do I need if I get ‘duck fleas’?
The rash will eventually go away of its own accord but it may take between 10-20 days to disappear completely.
If you have just a few itchy patches, you may not need any treatment. However, most of the time, itching is quite intense. It is important to control itching because scratching can damage your skin further and sometimes lead to a secondary bacterial infection which may need treatment with antibiotics.
Calamine lotion or an antihistamine may help to treat itching. Antihistamine liquid is available for children. However, do take care when using antihistamines as some can make you drowsy and so you should not drive whilst taking them. Always read the packet leaflet carefully and get advice from your local pharmacist to make sure that they are safe for you to use. For example, antihistamines may not be safe in certain medical conditions or if you are pregnant or breastfeeding.
A mild corticosteroid cream such as 1% hydrocortisone can also sometimes be helpful. Again, get advice from a pharmacist before using this. Rarely, in very severe cases, steroids taken by mouth may be needed.
How can I avoid ‘duck fleas’?
As suggested by CIPEL (International Commission for the protection of Leman Waters):
- Take a shower as soon as you get out of the water. Most of the beaches around the lake have showers available on the lakeside.
- Dry yourself off with a towel after your shower. The brisk rubbing motion with a towel can help to stop the larvae from penetrating your skin.
- Avoid swimming close to the plants and vegetation at the water’s edge as these can be a particular habitat for the parasite
Also some general points about safety around water:
Always take care whilst swimming in the lake or anywhere else. Many drowning incidents could have been prevented.
- Never leave children unattended. If you are watching children playing in or near water, take care not to become distracted by e.g. talking on your phone, reading etc.
- Learn to swim. Teach children to swim.
- Don’t swim alone; swim with a buddy.
- Don’t swim whilst under the influence of alcohol.
- Know the water where you are swimming. Remember that lakes and rivers can have strong currents.
- Don’t dive or jump into unfamiliar or shallow water.
- Everyone on board should wear a life jacket when in a boat.
- At home: use fencing with locked gates around pools. Use pool alarms/pool covers.