Japanese monkey (Macaca fuscata) with alveolar echinococcosis after treatment with albendazole for 10 years: serodiagnosis and determination of albendazole metabolites

First detection of Echinococcus multilocularis infection in two species of nonhuman primates raised in a zoo: a fatal case in Cercopithecus diana and a strongly suspected case of spontaneous recovery in Macaca nigra

The causative parasite of alveolar echinococcosis, Echinococcus multilocularis, maintains its life cycle between red foxes (Vulpes vulples, the definitive hosts) and voles (the intermediate hosts) in Hokkaido, Japan. Primates, including humans, and some other mammal species can be infected by the accidental ingestion of eggs in the feces of red foxes. In August 2011, a 6-year-old zoo-raised female Diana monkey (Cercopithecus diana) died from alveolar echinococcosis. E. multilocularis infection was confirmed by histopathological examination and detection of the E. multilocularis DNA by polymerase chain reaction (PCR). A field survey in the zoo showed that fox intrusion was common, and serodiagnosis of various nonhuman primates using western blotting detected a case of a 14-year-old female Celebes crested macaque (Macaca nigra) that was weakly positive for E. multilocularis. Computed tomography revealed only one small calcified lesion (approximately 8mm) in the macaque's liver, and both western blotting and enzyme-linked immunosorbent assay (ELISA) showed a gradual decline of antibody titer. These findings strongly suggest that the animal had recovered spontaneously. Until this study, spontaneous recovery from E. multilocularis infection in a nonhuman primate had never been reported.

Chemotherapy in alveolar echinococcosis of multi-organs: what's the role?

The aim of this study was to investigate the clinical efficiency of chemotherapy for the treatment of human alveolar echinococcosis (AE). Twenty-four patients who suffered from late-stage AE were enrolled in this study. The classification of the disease stages was performed according to the PNM (parasite lesion, neighboring organ invasion, metastases) classification system established by the World Health Organization Informal Working Group on Echinococcosis and classification standards. Radical surgery (n = 3), palliative surgery plus chemotherapy (n = 11), and sole chemotherapy (n = 10) were given, respectively. For those with AE metastasis with spleen and kidney, radical surgery was effective for the treatment. However, the treatment efficiency for those with AE metastasis to bone tissues was unfavorable. Significant improvement was noted in those with cerebral lesions after chemotherapy. Stable health conditions were observed in those with pulmonary lesions after chemotherapy. For those with liver lesion, long stable health conditions were noted after chemotherapy. However, surgical interventions were needed as the occurrence of bile duct complications. With regards to the other lesions, radical surgeries were recommended. Satisfactory treatment outcomes were obtained in those with AE after chemotherapy.

Time course of the antibody response in humans compared with rats experimentally infected with hepatic alveolar echinococcosis

Human alveolar echinococcosis (AE) is caused by the accidental ingestion of Echinococcus multilocularis eggs. Early detection is essential as surgical resection is the only treatment for a complete cure. However, details are unclear about changes in the antibody response during the initial stages of infection, yet such information is useful for early serodiagnosis. Therefore, a long-term investigation was performed into the time course of the antibody response before 'positive' detection. Patient sera were used for enzyme-linked immunosorbent assay (ELISA) and Western blotting (WB) analysis using crude antigens extracted from E. multilocularis protoscoleces. Rats were experimentally infected with AE and similarly analysed by ELISA and WB. Among the markers for diagnoses, the 18 kDa band (main marker) appeared last in the preoperative stages and disappeared first after operation in a WB test. Although the 18 kDa antigen can be useful as a marker for AE diagnosis, it cannot contribute to the detection of some patients before the 18 kDa band appearance. To avoid misdiagnosis, different diagnostic antigens such as the 26-28 and 7-8 kDa bands should also be considered. These bands tend to appear earlier than the 18 kDa band and thus offer the potential for early detection of AE. We first observed changes in the antibody response in a relatively early stage after infection in human AE cases. Notably, changes in the antibody response of two intermediate species were similar. These findings provide valuable information for the early detection of human AE cases in the future.