Full length article Investigation of infectivity of neonates and adults from different rat strains to Toxoplasma gondii Prugniaud shows both variation which correlates with iNOS and Arginase-1 activity and increased susceptibility of neonates to infection Jiang-Mei Gao a , Si-Qi Yi a , Ming-Shui Wu a , Guo-Qing Geng a , Ji-Long Shen b , Fang-Li Lu c , Geoff Hide d , De-Hua Lai a, *, Zhao-Rong Lun a,d, ** a Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Key Laboratory of Tropical Disease Control of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, China b The Anhui Provincial Laboratory of Pathogen Biology, Anhui Medical University, Hefei 230032, China c Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China d Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK H I G H L I G H T S • Different strains of rat show variation in resistance to T. gondii infection. • The balance of iNOS/Arginase-1 activity of host is strongly linked to resistance. • The rat is a good model for understanding toxoplasmosis in humans. • Neonates of rat already show similar resistance to Toxoplasma infection as adults. G R A P H I CA L A B ST R AC T * Corresponding author. Fax: +86-20-84036215. E-mail address: laidehua@mail.sysu.edu.cn (D-H. Lai). ** Corresponding author. Fax: +86-20-84036215. E-mail address: lsslzr@mail.sysu.edu.cn (Z-R. Lun). http://dx.doi.org/10.1016/j.exppara.2014.12.008 0014-4894/© 2014 Elsevier Inc. All rights reserved. Experimental Parasitology 149 (2015) 47–53 Contents lists available at ScienceDirect Experimental Parasitology journal homepage: www.elsevier.com/locate/yexpr