Cervical dermatitis

Classification according to ICD-10
B65.3	Cervical dermatitis
ICD-10 online (WHO version 2019)

Red wheals on the lower leg and ankle of an already sensitized person four days after the cercariae infestation

The bathing dermatitis is a harmless extending infestation of humans with tiny larvae of flukes of the genus Trichobilharzia spp., Including Trichobilharzia szidati . The infestation of humans happens by mistake; from the point of view of the worm larvae they are a so-called false host .

In medical terms , one also speaks of cercariae - dermatitis or schistosomatid dermatitis . The veterinary medicine means the disease as Entenbilharziose , popularly is called Weiherbeiß (Southern Germany) or duck fleas (Switzerland).

Occurrence

The disease was first described in the 1920s and occurs today worldwide, but predominantly in North America and Central Europe. The actual final hosts are water birds, mainly ducks; The first intermediate hosts are aquatic lung snails, especially of the genera Lymnaea (e.g. European mud snail ) and Radix .

Development cycle

Cercaria (approx. 1 mm long)

Water birds infested by trematodes release worm eggs into the water through their excrement. The hatched larvae of the first generation (miracidia) attack water snails as intermediate hosts. After any other intermediate hosts such as fish or tadpoles , the third generation of larvae - the cercaria  - enter the water again. These larvae look for a definitive host (duck bird), penetrate its skin and develop into sexually mature flukes in its intestines. The larvae are mainly released at temperatures above 24 ° C. The skin of people bathing is also mistakenly pierced. There, however, the cercaria die off after a short time. In mice, survival and infestation of the alveoli for several days without an immune reaction taking place, as well as the nervous system (by Trichobilharzia regenti ), whereby nerve tissue is destroyed by the cercaria, which leads to paralysis, has also been observed . At this point in time (as of 2015), this cannot be completely ruled out for humans, but no such cases are known to date.

Clinical picture in humans

Large-scale secondary infestation with increased reaction

At first, the infestation causes itching and only a minor local reaction of the skin, similar to a mosquito bite. A second infestation leads due to the immunological memory , however, to a much stronger immune response of the body, which after several hours as severe itching and reddish wheals - or papulation noticeable at the respective point of penetration. After 10 to 20 days, the lesions heal completely with or without therapy; the itching will subside after a few days. The infestation is uncomfortable and annoying, but usually harmless - in contrast to schistosomiasis in predominantly subtropical and tropical countries.

prevention

• Do not feed ducks - the more feed, the more ducks, more droppings and more cercaries,
• avoid shallow and water-plant-rich riparian zones,
• use waterproof sunscreens,
• After bathing, dry the body vigorously with a towel, so that parasites that have only partially penetrated the skin are removed, and swiftly change bathing clothes as well
• Do not scratch the itchy areas, otherwise there is a risk of secondary infections with bacteria or other germs.
• Prefer cooler waters or do not stay long in the (warmer) shore zone, but swim in areas where the water is cooler.

There is currently no effective, ecologically acceptable control method.

A waterproof skin cream with 0.5 to 1% niclosamide content killed the cercaria completely before penetration.

Bathing pond in your own garden

When planning, you should pay attention to a separation of the swimming zone from the planted areas. Measures should be taken to drive away ducks. Ducks often visit garden ponds in the months of March / April when looking for breeding grounds. They are diurnal and seek out open water or other safe places to sleep.

The snails that serve as intermediate hosts feed on rotting parts of plants. Therefore, dead plant remains should be removed as much as possible. Since the larvae ejected by infected snails only survive for about 24 hours outside of the snails, collecting snails with a net is one way of noticeably reducing the risk of infection on the following days. On the other hand, because of their role in the destruction of algae and dead plant parts, the snails are important for the ecological balance of the pond. Their absence can lead to increased algae growth. The removal is also laborious and only practicable for swimming ponds that do not exceed a certain size.

literature

• Stefan Werner u. a .: Bathing dermatitis - ecology and occurrence of the trigger Trichobilharzia franki on the shores of Lake Constance and development of measures to reduce the infestation , in: Writings of the Association for the History of Lake Constance and its Surroundings , 123rd year 2005, pp. 257-274 ( digitized version )

Web links

• Bathing dermatitis patient information from NetDoktor.at
• Life cycle of cercaria; Difficulties in combating ( memento of July 17, 2012 in the Internet Archive )
• Research project at the Natural History Museum Vienna
• Researchers develop protective cream against "bath dermatitis"

Individual evidence

1. ↑ ^{a b} Tomáš Macháček, Libuše Turjanicová, Jana Bulantová, Jiří Hrdý, Petr Horák: Cercarial dermatitis: a systematic follow-up study of human cases with implications for diagnostics . In: Parasitology Research . tape 117 , no. December 12 , 2018, ISSN  0932-0113 , p. 3881-3895 , doi : 10.1007 / s00436-018-6095-0 ( springer.com [accessed July 21, 2019]).
2. ↑ Süddeutsche Zeitung : Where the Weiherbeiß lurks , July 19, 2016, accessed on July 2, 2019
3. ↑ Stefan Werner: When it itches and bites in summer ...: The bath dermatitis. Limnological Institute, University of Konstanz, bodensee-ufer.de (PDF; 54 kB)
4. ^ W. Haas, U. Pietsch: Migration of Trichobilharzia ocellata schistosomula in the duck and in the abnormal murine host . In: Parasitol Res. , 1991, 77 (7), pp. 642-644, PMID 1792237 .
5. ↑ M. Chanová et al .: Trichobilharzia szidati: the lung phase of migration within avian and mammalian hosts . In: Parasitol Res. , 2007 May, 100 (6), pp. 1243-1247
6. ↑ L. Lichtenbergová et al .: Trichobilharzia regenti: Host immune response in the pathogenesis of neuroinfection in mice . In: Exp Parasitol. , 2011 May 1
7. ↑ L. Kolářová et al .: Histopathology of CNS and nasal infections caused by Trichobilharzia regenti in vertebrates . In: Parasitol Res. , 2001 Aug, 87 (8), pp. 644-650.
8. ↑ L. Kolářová et al .: Histopathology of CNS and nasal infections caused by Trichobilharzia regenti in vertebrates. In: Parasitology Research. Aug. 2001, Vol. 87, No. 8, pp. 644-50, doi: 10.1007 / s004360100431 .
9. ↑ L. Lichtenbergová et al .: Trichobilharzia regenti: Host immune response in the pathogenesis of neuroinfection in mice. In: Experimental Parasitology. August 2011, Vol. 128, No. 4, pp. 328-335, doi: 10.1016 / j.exppara.2011.04.006 .
10. ↑ www.badegewaesser.niedersachsen.de: Bathing dermatitis caused by cercariae in European inland waters , (" After bathing, the body [should] first be dried well, better properly rubbed off. Showering promotes the survival of the cercariae and penetration into the skin. Therefore, should it won't follow until a little later. "), accessed on July 2, 2019
11. ↑ Dredging against skin irritation ( Memento from August 19, 2010 in the Internet Archive )
12. ↑ C. Wulff et al .: Cream formulations protecting against cercarial dermatitis by Trichobilharzia . In: Parasitol Res. , 2007 Jun, 101 (1), pp. 91-97, PMID 17252275 , Epub 2007 Jan 25. See also M. Kalbe: Page no longer available , search in web archives: Trichobilharzia spec. - The causative agent of bathing dermatitis and possible control strategies . (PDF) p. 25f.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !