BEHAVIORAL AND MEMORY CHANGES IN Mus musculus COINFECTED BY Toxocara canis AND Toxoplasma gondii

Abstract

Several researchers have stated that parasites can alter the behavior of their hosts, in order to increase the transmission rate, principally when prey-predator relationships are a reliable way of infection transmission. The aim of this study was to verify the occurrence of changes in anxiety and short-term memory patterns in experimentally infected Mus musculus by Toxocara canis and/or Toxoplasma gondii. Forty male Mus musculus (Balb/c) eight-week-old were divided into four groups of 10 mice each. One group was infected with 300 eggs of Toxocara canis; a second group was submitted to infection with 10 cysts of Toxoplasma gondii; a third group was concomitantly infected with both parasites with the same inoculums and the last group was maintained without infection. The anxiety levels were evaluated using an elevated plus maze and an actometer; the short-term memory was determined by a two-way active avoidance equipment. The determination of anxiety levels were conducted 40 and 70 days after infection and the short-term memory was evaluated 140 days after infection. Mice chronically infected by Toxoplasma gondii showed impaired learning and short-term memory, but no significant differences were found in mice infected by Toxocara canis or concomitantly infected by Toxocara canis and Toxoplasma gondii when compared to non infected mice.

Conflicts over host manipulation between different parasites and pathogens: Investigating the ecological and medical consequences

“…Doubly infected rats slightly resemble T. canis rats in their behaviour [58]. However, singly infected animals behave similarly to each other [57,58], not illustrating any clear conflict between the parasites. These studies indicate that two parasites with conflicting interests could both have an effect on host behaviour leading to host behaviour that unites traits of hosts that are singly infected by either parasite.…”

“…In such a case, some functional experiments would be necessary to test whether transmission to each host is maximised by an optimal level of host manipulation or whether one parasite is simply unable to induce the maximal level of host manipulation [25]. Debilitation [103] No clear differences between singly infected hosts [57] Conflict between different transmission strategies (i.e. trophic transmission vs. growth and reproduction on/ in the current host)…”

Association between toxocariasis and cognitive function in young to middle-aged adults

“…Similarly, Correa et al (2014) performed a parallel study in mice and found that although mice infected with T. gondii had worse learning and memory compared to controls, mice with both T. gondii and Toxocara performed normally as did mice only infected with Toxocara. It is unclear if a similar effect would be seen in humans.…”

Zoonotic parasites carried by invasive alien species in China

“…mansoni [ 188 ] Sarcocystis sp. [ 180 ] Babesia microti [ 98 ] T. spiralis, Entamoeba coli, Dientamoeba fragilis [ 189 ] Mus musculus House mouse Enterocytozoon bieneusi [ 190 ] C. hepaticum [ 191 ] C. parvum [ 183 ] H. nana [ 192 ] H. diminuta, S. muris, T. taeniaeformis [ 193 ] Leishmania major [ 194 ] A.s cantonensis [ 195 ] H. taichui [ 196 ] T. gondii [ 197 ] T. canis [ 198 ] E. multilocularis [ 199 ] Rattus tanezumi Temminck Asian house rats A. cantonensis, Hymenolepis spp., T. taeniaeformis [ 200 ] Syphacia muris, H. diminuta [ 201 ] T. gondii [ 202 ] C. hepaticum [ 203 ] B. microti [ 98 ] Artyfechinostomum malayanum, Echinostoma ilocanum, E. lindoense, H. nana, M. moniliform...…”