Contents lists available at ScienceDirect Acta Tropica journal homepage: www.elsevier.com/locate/actatropica Molluscicidal potential of Heterorhabditis baujardi (Rhabditida: Heterorhabditidae), strain LPP7, on Lymnaea columella (Gastropoda: Pulmonata): An alternative for biological control of fasciolosis Victor Menezes Tunholi a, ⁎ , P.O. Lorenzoni a , Ygor Henrique da Silva a , Vinícius Menezes Tunholi-Alves b,f , Jankerle Neves Boeloni a , Maria Aparecida da Silva c , Caio Oliveira Monteiro d , M.C.A. Prata e , J. Pinheiro b,f , Isabella Vilhena Freire Martins a a Departamento de Medicina Veterinária, Centro de Ciências Agrárias e Engenharias, Universidade Federal do Espírito Santo—UFES, Alegre, ES, Brazil b Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil c Departamento de Biologia, Centro de Ciências Exatas, Naturais e da Saúde, Universidade Federal do Espírito Santo—UFES, Alegre, ES, Brazil d Departamento de Microbiologia, Imunologia, Parasitologia e Patologia da Universidade Federal de Goiás, Rua 235, s/n, Setor Universitário, Goiânia, Goiás, CEP: 74605- 050, Brazil e Laboratório de Parasitologia da Unidade de Pesquisa da Embrapa Gado de Leite (Embrapa CNPGL), Juiz de Fora, MG, Brazil f Departamento de Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil ARTICLE INFO Keywords: Reproductive biology Parasitic castration Snail-entomopathogenic nematode (EPN) relationship Microbial control ABSTRACT This study elucidated for the first time, under laboratory conditions, the susceptibility of Lymnaea columella to infective juveniles of Heterorhabditis baujardi LPP7. Exposure to the nematodes induced an average mortality rate of 66.66% in the population of L. columella, with the highest values attained from the second week after exposure onward. In addition, all the reproductive parameters analyzed (total number of eggs, number of egg masses, number of eggs laid/snail, embryo hatching rate and content of galactogen stored in the albumen gland) changed as a result of the infection. The results indicate the occurrence of the phenomenon of parasitic castration in L. columella infected by H. baujardi LPP7, probably through depletion of energy reserves such as galactogen, necessary to meet the intense metabolic demands of the nematode’s larval stages. Finally, histopathological analysis demonstrated an intense process of cell disorganization, characterized by the occurrence of granulomatous inflammatory reactions in tissues of exposed snails, induced by the spoliative action of the bacteria/nematode. The results suggest the use of H. baujardi LPP7 as an alternative for biological control of the population of this intermediate host, and thus of the diseases in whose epidemiological chain it participates, especially fasciolosis, in line with the recommendations of the World Health Organization (WHO). 1. Introduction Lymnaea columella (Say, 1817) is an aquatic snail that is commonly found in stagnant pools and slow-moving watercourses in Neotropical regions. With both lungs and gills, adults and juveniles of Lymnaea have amphibious behavior, with the ability to survive temporarily or even for long periods out of their natural aquatic habitat (Jurberg et al., 1997). These snails participate in the epidemiological chain of fasciolosis, acting as the intermediate host in the life cycle of the etiological agent of this parasitosis (Oakley et al., 1979). The disease is caused by two trematode species: Fasciola hepatica (Linnaeus, 1758) and Fasciola gigantica (Cobbold, 1855) (Mattos et al., 2009). Both are highly relevant helminths in veterinary medicine and public health, by parasitizing the biliary ducts and vessels of domestic ruminants, wild animals and occasionally humans, so that the disease is classified as an important anthropozoonosis (Oliveira and Spósito Filha, 2009; Mas-Coma, 2005). The participation of snails of this genus as hosts in the cycle of Fasciola sp. has been demonstrated by many researchers in studies involving experimental infections, along with reports of the occurrence of natural infection (Coelho et al., 2008, 2009; Pinheiro et al., 2009; Farinazzo et al., 2001). The aim of these studies has been to clarify the life cycle of Fasciola sp. and other trematodes, besides evaluating the host’s behavior when infected, since modifications induced by the parasite in the body of snails during infection cause a wide range of responses, especially alterations in the reproductive pattern and growth of the hosts (Tunholi et al., 2011; Dreyfuss et al., 1999; Jong-Brink, http://dx.doi.org/10.1016/j.actatropica.2017.05.024 Received 5 March 2017; Received in revised form 15 May 2017; Accepted 20 May 2017 ⁎ Corresponding author. E-mail address: victortunholi@yahoo.com.br (V.M. Tunholi). Acta Tropica 173 (2017) 23–29 Available online 22 May 2017 0001-706X/ © 2017 Elsevier B.V. All rights reserved. MARK