Frances Ramírez de Arellano Canetti, and Amanda Torres Arroyo
The parasitic disease Schistosomiasis, also known commonly as bilharzia, is caused by the worm Schistosoma mansoni. It is currently the second most prevalent parasitic disease globally following malaria. It is estimated that more than 200 million people are infected worldwide. This parasite uses the snail Biomphalaria glabrata as an intermediate host during its life cycle affecting the behavior of the snail. The specific neuronal mechanisms involved in these changes have not been identified. If the parasitic infection by S. mansoni causes physiological and behavioral changes in its intermediate host, B. glabrata, then changes in the neural distribution or expression in infected snail nodes can be detected because they are being regulated by their neuropeptide system. The understanding the CNS of B. glabrata helps the possibility of finding a way to interfere with the transmission of schistosomiasis. It is important to have deeper knowledge about this parasite-host relationship to be able to eradicate this disease. This investigation intended to examine the CNS of an uninfected snail by using standard immunohistochemistry to locate the neuropeptide pedal peptide 4 (PP4). If PP4 is reactive in certain ganglions in the CNS of the snail, then its role in the behavior of the snail can be better understood. It was found that PP4 showed immunoreactivity across the entire CNS, the more significant reactive neurons were mainly in the buccal, pedal, and cerebral ganglia. The localization of these neurons showed that PP4 is likely involved in the feeding behavior of the snail.
Further comparison of this information with PP4 in the CNS of an infected snail is needed to completely understand how the function of this peptide is altered during the infection by the parasite. The interdisciplinary nature of this study comes from the incorporation of different scientific fields such as parasitology, neurobiology, immunology, and ecology.
Keywords: Biomphalaria glabrata, immunohistochemistry, neurobiology, Schistosomiasis mansoni