Evaluation of a New Immunochromatographic Test Using Recombinant Antigen B8/1 for Diagnosis of Cystic Echinococcosis.

Diagnosis of cystic echinococcosis (CE) is based on the identification of the cyst(s) by imaging, using immunodiagnostic tests mainly as complementary tools in clinical settings. Among the antigens used for immunodiagnosis, previous studies described a good performance of the recombinant antigen B8/1 (rAgB) in an enzyme-linked immunosorbent assay (ELISA) format; however, in remote parts of areas where the disease is endemic, the implementation of an ELISA is difficult, so a more simple, rapid, and reliable method such as the immunochromatographic test (ICT) is required. In this study, using a set of 50 serum samples from patients with surgically confirmed CE, we compared the performance of an ICT and that of an ELISA using the rAgB. The overall sensitivities of ICT and ELISA were not statistically different (78% versus 72%; P = 0.36). The overall agreement between both tests was moderate (κ = 0.41; P < 0.01). Concordance between ICT and ELISA was substantial or almost perfect for patients with liver involvement (κ = 0.65; P < 0.001) and patients with more than one hydatid cyst (κ = 0.82; P < 0.001), respectively. Moreover, specificity analysis using a total of 88 serum samples from healthy individuals (n = 20) and patients (n = 68) with other parasitic infections revealed that ICT had a specificity of 89.8%. ICT and ELISA had similar performance for the detection of specific antibodies to E. granulosus, and ICT had a high specificity, opening the possibility of using ICT as a screening tool in rural settings.

Efficacy of diverse antiparasitic treatments for cysticercosis in the pig model.

Taenia solium cysticercosis infects pigs and humans. Because antiparasitic treatment for human cysticercosis has sub-optimal efficacy, alternative regimes are needed. Seven antiparasitic regimens were tested in 42 naturally infected pigs with cysticercosis, and compared with prednisone alone (n = 6) or no treatment (n = 6). The numbers of viable cysts in muscles and in the brain were examined after necropsy and were significantly decreased in pigs receiving combined albendazole plus praziquantel, albendazole alone, or oxfendazole. Pigs receiving praziquantel alone and nitazoxanide had numerous surviving cysts. Control (untreated) pigs and prednisone-treated pigs had many more viable cysts, suggesting no effect. Combined albendazole plus praziquantel, and oxfendazole, showed a strong cysticidal effect and provide suitable alternative treatments to be further explored for their use for treatment of human neurocysticercosis.

Human hydatid disease in Peru is basically restricted to Echinococcus granulosus genotype G1.

A molecular PCR study using DNA from 21 hydatid cysts was performed to determine which strain type is responsible for human infection in Peru. The mitochondrial cytochrome c oxidase subunit 1 (CO1) gene was amplified in 20 out of 21 samples, revealing that all but 1 sample (19/20, 95%) belonged to the common sheep strain (G1). The remaining samples belonged to the camel strain (G6). The G1 genotype was most frequently found in human cases of cystic hydatid disease (CHD) in Peru. Local control measures should focus primarily on decreasing dog and sheep infection rather than intermediate reservoirs.

Can Taenia solium latent post-oncospheral stages be found in muscle tissue of cysticercosis-infected pigs (Sus scrofa)?

The existence of latent Taenia solium post-oncospheral stages in the tissues of infected pigs has been postulated. To assess whether such structures exist and can be detected, we examined muscle samples from cysticercosis-infected and uninfected pigs. Pork samples were homogenized, centrifuged, and resuspended in saline solution. Round microscopic structures of approximately 10 microm with variable refringence were found in the pellets of all samples from both infected and uninfected pigs. These became homogeneously red after staining with Sudan IV and disappeared after ether extraction. The only difference between samples from infected and uninfected pigs was the presence of inflammatory cells and tissue necrosis debris in the former group. Taenia solium oncospheres were stained and observed for comparative purposes, before and after inoculation into pork. Control oncospheres were ellipsoidal, had nucleated basophile cells in their interior, and showed red aggregates on their surfaces when stained with 3% Sudan IV. While rounded microscopical structures similar to those previously reported were found, these differed morphologically from oncospheres, were of a lipid nature, and occurred in both infected and uninfected animals. No evidence supporting the presence of latent post-oncospheral stages of Taenia solium was generated in this series of experiments.