The life cycle of Trypanosoma murmanensis Nikitin

Abstract

Trypanosoma murmanensis from the blood of the Atlantic cod, Gadus morhua, undergoes multiplicative development in the digestive tract of a marine leech Johanssonia sp. as the amastigote and sphaeromastigote stages. Epimastigotes, which apparently do not divide, migrate later to the proboscis of the leech and subsequently transform to metatrypomastigotes that are transmitted during engorgement. Fine granules of yellow pigment, observed in all stages, eventually disappear in the metatrypomastigotes. The cycle in the leech is completed in 62 days at 0–1 °C but is more rapid (42 days) at 4–6 °C. Cod-fed infected leeches remained aparasitemic. Trypomastigotes did not develop in two species of parasitic copepods, Lerneocera branchialis and Clavella adunca.Small, slender trypomastigotes, which appear from 3 days after infection, grow into larger forms that subsequently acquire myonemes. The average maximum size occurs about 55 days after infection. There is always a range of sizes, which becomes more apparent as the parasitemia declines from about 29 days. Parasitemias vary from 105 per millilitre to numbers too few to estimate accurately. No divisional forms were observed in cod and increased parasitemias do not apparently occur after inoculations of infected blood.