Changes in the locomotory and reproductive behavior of Biomphalaria glabrata infected with Schistosoma mansoni

Abstract

The infection and development of a parasite may cause physiological, morphological and behavioral changes in its host. Changes in the locomotory activity of a host induced by their parasites may also influence the life-cycles of both host and parasite in the environment. The aim of the present work was to evaluate the locomotory activities of Biomphalaria glabrata before and after an experimental infection with Schistosoma mansoni relating to the shedding of cercaria. In addition, the reproductive parameters of infected B. glabrata were analyzed during the prepatent and patent periods of the infection. The locomotory activity was recorded using an image analysis biomonitoring system based on a Videomex V. Five parameters were analyzed: 'Distance traveled', 'Ambulatory time', 'Stereotypic time', 'Resting time' and 'Average speed'. The number of shed cercariae was counted twice at 45 and 52 days post-infection. The reproductive parameters of infected B. glabrata analyzed were the numbers of egg masses, eggs and hatched snails. All statistical analyses were performed using the R program. Of the 69 snails infected with S. mansoni, 33 (47.8%) shed cercariae ('positive') and 36 (52.2%) ('exposed') failed to exhibit any cercarial shedding prior to the end of the experiment. The locomotory activity of the all snails increased significantly after infection with S. mansoni. However, when the 'positive' and 'exposed' snails were compared, the former, shedding cercariae, were less motile. With regard to reproduction, 84.8% (28/33) of the 'positive' and 27.7% (10/36) of the 'exposed' snails failed to lay egg masses during patent period. The number of cercariae individually shed by each 'positive' snail presented a positive relation with 'Stereotypic time' and a negative relation with egg laying. Our findingshighlight the way in which infection with S. mansoni affects the locomotory and the reproductive behavior of B. glabrata. The number of cercariae shed is directly associated with the reduction/interruption in egg-laying and with an increase in random movement.

The spatial spread of schistosomiasis: A multidimensional network model applied to Saint-Louis region, Senegal

“…These findings call for a more in-depth description of the snail locomotory behavior and the peculiar hydrologic conditions of the region under study (OMVS, Organisation pour la mise en valeur du fleuve Sénégal, 2003). In particular, the locomotion of snails may be different according to their infection status (Boissier, Rivera, Moné, 2003, Alberto-Silva, Santos, Santos, Mello-Silva, 2015); also, the temporal variability of flood stages, as determined by seasonal rainfall, may have important implications for water contact patterns, as well for the life cycle of snail hosts and larval organisms. Even the environmental alterations induced by the construction of the Diama Dam need be addressed in the context of disease transmission (Southgate, 1997, Sow, De Vlas, Engels, Gryseels, 2002): on the one hand, in fact, the dam has changed the Senegal basin’s flood plain from a salty and brackish aquatic environment with marked seasonal changes to a low-flow perennial freshwater system; on the other, it has raised water levels in the upstream section of the river, thus creating reserves for irrigation (OMVS, Organisation pour la mise en valeur du fleuve Sénégal, 2003).…”

Opportunity or catastrophe? effect of sea salt on host-parasite survival and reproduction

“…Some authors have suggested that in contrast to miracidia, cercariae, which infect humans, require less energy for osmoregulation due to the lower difference between external and internal salinity to a certain threshold [ 56 ]. Therefore, cercariae seem to possess a higher tolerance than their snail hosts to increasing salinity, which may drive the observed non-linear relationship between cercarial survival and seawater concentration [ 34 and references therein].…”

“…During weekly water changes, egg masses were counted and removed from jars. While individual eggs were not counted, previous studies have demonstrated a strong correlation between number of eggs and number of egg masses [ 33 , 34 ].…”

Reproductive alterations of Biomphalaria glabrata (Say, 1818) infected with Angiostrongylus cantonensis (Chen, 1935) and exposed to Euphorbia milii var. hislopii latex

“…Helminth infection and exposure to phytochemicals are known to modulate the survival and reproductive parameters of intermediate host snails (Moore, 2002;Oliveira-Filho et al, 2014;Alberto-Silva et al, 2015, 2020. Infection can cause partial or total disruption of oviposition and egg hatching, in addition to biochemical and histopathological changes, leading to a reduction in the population of infected snails (Faro et al, 2013;Guerino et al, 2017).…”

“…Infection can cause partial or total disruption of oviposition and egg hatching, in addition to biochemical and histopathological changes, leading to a reduction in the population of infected snails (Faro et al, 2013;Guerino et al, 2017). Regarding infection, these effects have been studied in models such as Biomphalaria glabrata (Say, 1818) infected by Schistosoma mansoni (Sambon, 1907) (Minchella and Loverde, 1981;Vasconcellos and Schall, 1986;Lima, 2010;Faro et al, 2013;Alberto-Silva et al, 2015); B. glabrata infected by Echinostoma paraensei Lie andBasch, 1967 (Tunholi et al, 2011), B. glabrata co-infected by E. paraensei and Angiostrongylus cantonensis (Chen, 1935) (Bonfim et al, 2014;Garcia, 2014); B. glabrata infected by A. cantonensis (Tunholi-Alves et al, 2011); Biomphalaria straminea (Dunker, 1848) and Biomphalaria tenagophila (D'Orbigny, 1835) infected by A. cantonensis (Lima et al, 2017) and Bulimulus tenuissimus (D'Orbigny, 1935) infected by Angiostrongylus cantonensis (Martins et al, 2019).…”