Ling-Yuh Shyu1, Hao-Hung Tsai2,3, Shin-Tai Chong2, Tzu-Hua Lee2, Kwong-Chung Tung4, Jun-Cheng Weng2,3
1Department of Parasitology, Chung Shan Medical University, Taichung, Taiwan; 2School of Medical Imaging & Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan; 3Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan; 4Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
Angiostrongylus cantonensis (A. cantonensis) is the most common cause of eosinophilic meningoencephalitis in Taiwan. This parasitic infection is endemic in the Southeast Asian and Pacific region, but it becomes a global infection in recent years. The infection in the final host, rats, or non-permissive host, including human, is acquired by ingesting contaminated raw snails. The third-stage larvae migrate to the brain and develop into the fifth stage with twice molts. The worms then migrate to lung and heart and develop into adult. The typical clinical presentation is acute eosinophilic meningoencephalitis frequently accompanied by brain and spinal cord disorders, and other symptoms of central nervous system (CNS). The features of the pathological changes in the brain were previously limited to a few case reports and techniques. Previously the diagnosis was established by immunodiagnosis, lumbar puncture and eosinophilia examination. Fourth- or fifth-stage larvae could be found in the cerebrospinal fluid (CSF) with lumbar puncture. Improper puncture and false immune response resulted in an erroneous diagnosis. Therefore, the purpose of this study was to determine the lesion localization, pathological changes and angiostrongyliasis characterization of rat brain infected with larvae of A. cantonensis by magnetic resonance imaging (MRI) techniques. The results were verified with histopathological study. Rats were infected with different numbers of A. cantonensis larvae and their brains were diagnosed continuously with MRI and histopathological study. The association between the clinical features of the rats and MRI findings was also addressed.