Cellular Resistance against Schistosomula of Schistosoma Mansoni in Macaca Mulatta Monkeys Following Prolonged Infections *

The severity of mouse pathologies caused by the bird schistosome Trichobilharzia regenti in relation to host immune status

“…H&E, bar 75 lm which only led to an increase in the number of schistosomula trapped in the skin, the complete elimination of all the parasites in the skin was observed only in animals challenged ten times. Similar results were reported by Von Lichtenberg and Ritchie (1961) and Ellis et al (1975) who studied the efficacy compatible host immune response during primary and challenge infections with Schistosoma mansoni and T. ocellata infections, respectively. It seems, therefore, that effective killing of the schistosome larvae in the skin represents a common effect during host reinfection with cercariae.…”

Migration, development, and condition of Trichobilharzia ocellata (Trematoda: Schistosomatidae) in homologous challenge infections

“…Dead and dying worms were seen in these foci. Although there was an increased cellular response in lungs of ducks resistant to T. ocellata, it appeared to be more diffuse and more predominantly lymphoid than that described by Lichtenberg and Ritchie (1961). Only after worms became moribund did it involve large numbers of heterophils and other granular leucocytes.…”

“…The latter two symptoms were seen in the present work 2 to 3 days after exposure. Despite the cellular response, Lichtenberg and Ritchie (1961) reported no differences in the speed of cercarial progression from epidermis to dermis, nor in the number of cercariae persisting in the skin after 5 days. These authors reported that most larvae which were permanently trapped in the skin remained in the dermis.…”

“…Lichtenberg and Ritchie (1961) reported marked differences between the duration and severity of cercarial dermatitis in immune rhesus monkeys and in normal controls when exposed to cercariae of S. mansoni. At the peak of this reaction (24-48 h) they observed erosion and massing of polymorphonuclear leucocytes in the epidermis, followed later by hyperkeratosis, crust formation, and scaling.…”

“…Finally, almost no schistosomula were seen in lymphoid areas until day 6 in initial infections whereas there was an immediate and sustained lymphoid response to worms in the lungs of challenged birds. Lichtenberg and Ritchie (1961), in a study of S. mansoni in rhesus monkeys, showed that trapping of migrating schistosomula occurred mainly in the lungs. There was little or no cellular reaction in the lungs of initially exposed monkeys, but in resistant monkeys every schistosomulum became the centre of an inflammatory response, eventually involving polymorphs, eosinophils, lymphoid cells, and large mononuclear cells.…”