Toxocara Brain Infection in Pigs is Not Associated with Visible Lesions on Brain Magnetic Resonance Imaging

Abstract

Human exposure to Toxocara spp. is very frequent, and its larvae can cross the blood-brain barrier and invade the central nervous system (CNS), causing neurotoxocariasis. We aimed to establish a neurotoxocariasis animal model in pigs confirmed by necropsy. Also, the presence of larvae in the CNS was assessed using magnetic resonance imagings (MRIs), to establish brain lesions caused by the larvae migration. Ten pigs were infected intraperitoneally with 3,000 Toxocara larvae. Cerebral toxocariasis was evaluated using MRIs at days 7, 14, 21, and 49, and pigs were euthanized after the examination. Brain tissues were examined by microscopy, and five pigs presented Toxocara, most frequently at day 21 after infection. None of the 10 pigs showed alterations on MRIs. Our study confirms that intraperitoneal Toxocara infection produces neurotoxocariasis in pigs. Toxocara larvae passage through the brain does not seem to produce lesions detectable at MRIs.

“Begging the Question”—Does Toxocara Infection/Exposure Associate with Multiple Sclerosis-Risk?

“…Pathological changes associated with porcine cerebral toxocariasis include congestion, oedema, shrinkage of nerve cells, vacuolization, gliosis, satellitosis, neurophagia, and liquefactive necrosis [ 38 ]. However, it should be noted that, according to a recent study in pigs [ 64 ], the passage of Toxoxara larvae through the brain does not always induce lesions detectable by magnetic resonance imaging (MRI), suggesting that they do not cause structural lesions, thus leaving no detectable damage.…”