Taenia solium: Development of an Experimental Model of Porcine Neurocysticercosis

Abstract

Human neurocysticercosis (NC) is caused by the establishment of Taenia solium larvae in the central nervous system. NC is a severe disease still affecting the population in developing countries of Latin America, Asia, and Africa. While great improvements have been made on NC diagnosis, treatment, and prevention, the management of patients affected by extraparenchymal parasites remains a challenge. The development of a T. solium NC experimental model in pigs that will allow the evaluation of new therapeutic alternatives is herein presented. Activated oncospheres (either 500 or 1000) were surgically implanted in the cerebral subarachnoid space of piglets. The clinical status and the level of serum antibodies in the animals were evaluated for a 4-month period after implantation. The animals were sacrificed, cysticerci were counted during necropsy, and both the macroscopic and microscopic characteristics of cysts were described. Based on the number of established cysticerci, infection efficiency ranged from 3.6% (1000 oncospheres) to 5.4% (500 oncospheres). Most parasites were caseous or calcified (38/63, 60.3%) and were surrounded by an exacerbated inflammatory response with lymphocyte infiltration and increased inflammatory markers. The infection elicited specific antibodies but no neurological signs. This novel experimental model of NC provides a useful tool to evaluate new cysticidal and anti-inflammatory approaches and it should improve the management of severe NC patients, refractory to the current treatments.

Recent advancements and new perspectives in animal models for Neurocysticercosis immunopathogenesis

“…Most of our understanding about immunopathogenesis of cysticercosis is based on the mice or rat models, which cannot be extrapolated to human beings. A series of studies with T. solium have established that the course of infection and its histopathology and the response shown against antiparasitic treatment in swine is similar to the one in humans . However, a major drawback of this model is that being a large animal, the handling of pig is costly and requires a dedicated facility with skilled workforce.…”

“…Recently, Fleury et al., (2105) published a surgical method to directly infect the pig brain to develop an NCC model. In this method, eggs collected from human T. solium carriers were hatched in vitro using 0.75% sodium hypochlorite in water.…”

A Case of Neurocysticercosis Clinically Mimicking Epilepsy: Report from Remote Hilly Area of Bangladesh

“…Epidemiologic studies have demonstrated tight clustering household or household contacts with NCC patients have three times higher risk having positive serology for cysticercosis compared with controls 5 . NCC is a common cause of neurological disease transmitted through parasites called Taenia solium (T. solium) 6 . It is endemic in Africa, Asia and Latin America, making it the major cause of epilepsy and Bangladesh J Infect Dis 25 June 2016│ Volume 3│Number 1 convulsion in these regions 7 .…”

Experimental neurocysticercosis: absence of IL-4 induces lower encephalitis

“…In this model, the infected animals presented with tissue alterations and lesions such as encephalitis, perivasculitis, ventriculomegaly, ependymitis, meningitis, microgliosis accompanied by the parasite's death, and extraparenchymal and parenchymal inflammatory infiltration 6,18 . Other experimental models have been proposed but instead of using T. crassiceps cysticerci they performed an intracranial inoculation of T. solium oncospheres in rats 19 and in swine 20 . The rat NCC model reported that the infected animals presented with epilepsy, inflammatory infiltration, perivascular infiltrate, angiogeneses, spongy changes and mass effect in the brain tissue 19 .…”

“…The rat NCC model reported that the infected animals presented with epilepsy, inflammatory infiltration, perivascular infiltrate, angiogeneses, spongy changes and mass effect in the brain tissue 19 . In the swine NCC model, after four months of infection, it was possible to observe calcified cysticerci surrounded by an exacerbated inflammatory response with lymphocyte infiltration and increased inflammatory markers 20 . The BALB/c mice are genetically susceptible to intraperitoneal infection with T. crassiceps cysticerci because they present a Th2 immune profile 7,9 .…”