Host specificity and rejection of Schistocephalus solidus

Abstract

1. Procercoids of Schistocephalus solidus reared in copepods were found to infect marine and freshwater varieties of Gasterosteus aculeatus, and Pungitius pungitius, but not Barbus ‘Schuberti’.2. In primary infections growth of S. solidus plerocercoids in P. pungitius was much slower than in G. aculeatus and ceased after 6–8 days; plerocercoids were dead by day 11 at 19·5 °C, and by day 14 at 10 °C.3. A challenge infection, following two previous infections given 14 and 28 days before, becomes established in G. aculeatus, but in P. pungitius plerocercoids are rejected within 3–5 days.4. The possible rejection mechanism involved in P. pungitius to primary and tertiary infections is discussed and electronmicrographic evidence presented of a degenerative change in the tegument visible by 8 days in a primary infection. Prior to 8 days the survival and growth of S. solidus plerocercoids surgically transferred to G. aculeatus, indicated no irreversible damage had occurred.