Research on avian schistosomes

(Older team name: Schistosome Group Prague)

Trichobilharzia regenti

Trichobilharzia regenti is a neuropathogenic avian schistosome which has been discovered and described as a new species by our team in 1998. In addition to birds, the infectious larvae (cercariae) proved to penetrate also the skin of mammals and, therefore, T. regenti (neuro)pathogenicity is intensively investigated.

Adults of nasal bird schistosomes live in the bill mucosa, where also mating and egg laying take place. Histopathologically, petechiae caused by worm migration and egg deposition may occur.

Cercaria of T. regenti penetrates a peripheral nerve isolated from a duck (left). The target tissue of T. szidati migration is the intestinal wall of ducks. Some of the eggs laid by females are trapped in the tissue; formation of granulomas can be noticed macroscopically as well as microscopically in tissue sections.

Confocal laser scanning microscopy can be used for characterization of different organs/tissues of Trichobilharzia. Using specific probes, we focus on organogenesis and stage-specific morphological features of T. regenti. For example, the presence of polymeric or oligomeric F-actin in the eggs, miracidia, cercariae and schistosomula is shown.

Swimmer’s itch, also known as cercarial dermatitis, represents a common non-communicable waterborne cutaneous allergic disease which develops as a consequence of repeated infections by larval stages (cercariae) of schistosomatid flukes. Swimmer’s itch is usually associated with swimming in recreational freshwater lakes, and mostly cercariae of avian schistosomes of the genus Trichobilharzia are reported as a source of infection. Bathing in the sea or brackish waters is rarely mentioned with respect to cercarial dermatitis. Due to a higher number of reports on outbreaks, cercarial dermatitis may be regarded as an emerging disease.

CURRENT MAIN RESEARCH STREAMS in the study of avian schistosomes (laboratory models: Trichobilharzia regenti, Trichobilharzia szidati):

(1) Characterization of local and systemic immune response in primary infected or reinfected accidental hosts (i.e. mice) before and after the invasion of CNS

(2) Characterization of T. regenti migrating worms and products in CNS

(3) Diversity, distribution and detection of avian schistosomes in Czechia, cercarial dermatitis

Etymology of T. regenti declared in the original description (Horak et al. 1998): "Regent is a governor of a kingdom/principality; the title was frequently used in South Bohemia (i.e. the area where the schistosome comes from) in the Middle Ages. At present the name represents a famous South Bohemian brewery (founded in 1379)". Introduction of the name of T. regenti was meant as an appreciation of the brewery.

Workshops on Bird Schistosomes and Cercarial Dermatitis

From time to time, the scientists working on bird schistosomes organize a workshop. These events enable a valuable exchange of information:

1st Workshop - Czechia, Dolni Vestonice, September 10-14, 2001

2nd Workshop - France, Annecy, June 16-18, 2003

3rd Workshop - Czechia, Rejckov-Kouty, July 6-10, 2009