Comportamento da cepa LE de Schistosoma mansoni, após passagem em hospedeiro humano infectado acidentalmente

Abstract

Uma auxiliar de laboratório infectou-se acidentalmente, com cercárias de Schistosoma mansoni, cepa LE, mantida rotineiramente em nossos laboratórios. Decorridos 5 meses, o exame parasitológico de fezes revelou 108 ovos/g . A pacientefoi tratada com oxamniquine, porém a infecção continuou ativa (6 ovos/g). Foi então obtido o isolado SSF mantido no modelo Biomphalaria glabrata - camundongo albino. Os resultados obtidos no estudo comparativo, entre o isolado SSF e a cepa LE, que lhe deu origem, mostraram que a duração do período pré-patente e o índice de infectividade em camundongos, bem como a resposta aos agentes esquistossomicidas (hycanthone, oxamniquine epraziquantel) não apresentaram diferenças estatisticamente significativas. Por outro lado, o número de miracídios obtidos dos intestinos e fígados dos camundongos infectados foi o dobro com a cepa LE, quando comparados com aquele do isolado SSF. Também a variação do peso dos animais foi bastante diferente. Concluiu-se que apenas uma passagem pelo hospedeiro humano não mudou substancialmente as características da cepa estudada.

Experimental infection with Schistosoma mansoni isolated from the wild rodent Holochilus sciureus shows a low parasite burden but induces high schistosomiasis severity in BALB/c mice

“…Mann-Whitney test was performed to compare the granuloma area, and two-way ANOVA followed by Bonferroni's post-test was performed to compare hydroxyproline concentrations between the groups. adult worm recovery rate in experimental infections with the human-isolated parasite was even higher, reaching 31-34% (Katz et al, 1973;Araújo et al, 1986), dropping to 20-25% in recent publications (Maggi et al, 2021;Oliveira et al, 2022), a rate similar to that observed in the current study. Therefore, published data confirm that the long-term maintenance of S. mansoni from the LE strain under laboratory conditions contributes to modifying the infectivity rate of the parasite; however, it attenuated the difference between LE and HS parasite strains, indicating that the original host has an important role in this biological aspect of the parasite strain.…”

“…In addition to the host species from which the parasites were originally isolated (human vs wild rodent), the long-term maintenance of the LE parasite strain could also have contributed to the biological differences in the current study. Nevertheless, analysing data from published works that investigated the infectivity rate of the LE strain of S. mansoni in mice over the years, we observed that, just after the isolation, the adult worm recovery rate in experimental infections with the human-isolated parasite was even higher, reaching 31–34% (Katz et al , 1973; Araújo et al , 1986), dropping to 20–25% in recent publications (Maggi et al , 2021; Oliveira et al , 2022), a rate similar to that observed in the current study. Therefore, published data confirm that the long-term maintenance of S. mansoni from the LE strain under laboratory conditions contributes to modifying the infectivity rate of the parasite; however, it attenuated the difference between LE and HS parasite strains, indicating that the original host has an important role in this biological aspect of the parasite strain.…”