Neurocysticercosis and acquired cerebral toxoplasmosis in children

Infections in the immunocompromised child

Prevention and management of opportunistic infections in children is particularly relevant in an era demonstrating an increased prevalence of immunocompromising conditions. The presence of an unusual organism which results in serious infection in a child should therefore always raise the consideration of immune compromise. The more common opportunistic infections have become easier to recognize in recent times due to improved awareness and more refined diagnostic testing. Targeted treatment is usually followed by long-term prophylactic medication. The impact of these conditions on patient outcome is of clear significance and certainly warrants further discussion.

Acquired toxoplasmosis accompanied by facial nerve palsy in an immunocompetent 5-year-old child

Acquired toxoplasmosis, although relatively common in children, is usually asymptomatic but can also be clinically manifested by a benign and self-limited infectious mononucleosis-like syndrome. Neurological complications are very rare in immunocompetent children. The authors report a 5-year-old boy who presented with cervical lymphadenopathy because of acquired toxoplasmosis accompanied with unilateral facial nerve paralysis. Toxoplasma gondii DNA detection in blood by polymerase chain reaction, as well as elevated specific immunoglobulin M antibodies against it, established the diagnosis. Characteristic brain lesions on magnetic resonance imaging were absent and ophthalmologic examination revealed no inflammatory lesions in the retina and choroid. Treatment with pyrimethamine, sulfadiazine, and folic acid resulted in a complete recovery after 2 months of therapy. Although rare, acute facial nerve paralysis of unknown origin can be caused by acquired toxoplasmosis even in the immunocompetent pediatric population. Elevated titers of specific antibodies and the presence of parasite's DNA are key findings for the correct diagnosis.

Endoscopic excision of intraventricular neurocysticercosis in children: a series of six cases and review

OBJECTS

Neurocysticercosis (NCC) affects both adults and children, but it is uncommon in childhood. The clinical presentation and management of intraventricular neurocysticercosis (IVNCC) in children has not been described adequately. We, therefore, present our series of six children with IVNCC managed by endoscopic excision.

MATERIALS AND METHODS

A retrospective analysis of six children with IVNCC was performed. The endoscopic technique practiced is described. Complete excision of the intraventricular cyst was performed in all patients. Simultaneously, five endoscopic third ventriculostomies, one septostomy, and one foramenotomy were performed. There were no perioperative and postoperative complications. Mean follow-up duration was 24.8 months. Clinical improvement was seen in all children, and none required shunting. Follow-up radiology showed no residual lesion and decreased ventricle size in all patients.

CONCLUSION

Endoscopic IVNCC cyst excision along with internal CSF diversion is a safe and effective option and avoids shunt and its related complications in these children.

Toxoplasmosis, an overview with emphasis on ocular involvement

Toxoplasmosis is a common parasitic zoonosis and an important cause of abortions, mental retardation, encephalitis, blindness, and death worldwide. Although a large body of literature has emerged on the subject in the past decades, many questions about the pathogenesis and treatment of the disease remain unanswered. This review aims to provide an overview of the current insights regarding the causative parasite and the mechanisms leading to symptomatic infection with emphasis on ocular toxoplasmosis.

Lack of evidence for superantigen activity of Toxoplasma gondii towards human T cells

Toxoplasma gondii is an obligatory intracellular parasite whose life cycle may include man as an intermediate host. More than 500 million people are infected with this parasite worldwide. It has been previously reported that T. gondii contains a superantigen activity. The purpose of the present study was to determine if the putative superantigen activity of T. gondii would manifest towards human T cells. Peripheral blood mononuclear cells (PBMC) from individuals with no previous contact with the parasite were evaluated for proliferation as well as specific Vbeta expansion after exposure to Toxoplasma antigens. Likewise, PBMC from individuals with the congenital infection were evaluated for putative Vbeta family deletions in their T cell repertoire. We also evaluated, over a period of one year, the PBMC proliferation pattern in response to Toxoplasma antigens in patients with recently acquired infection. Some degree of proliferation in response to T. gondii was observed in the PBMC from individuals never exposed to the parasite, accompanied by specific Vbeta expansion, suggesting a superantigen effect. However, we found no specific deletion of Vbeta (or Valpha) families in the blood of congenitally infected individuals. Furthermore, PBMC from recently infected individuals followed up over a period of one year did not present a reduction of the Vbeta families that were originally expanded in response to the parasite antigens. Taken together, our data suggest that T. gondii does not have a strong superantigen activity on human T cells.

Detection and characterisation of parasites causing emerging zoonoses

Understanding the epidemiology of zoonotic parasitic infections is dependent upon the availability of accurate and sensitive diagnostic techniques. The development of molecular diagnostic methods, particularly those utilising PCR for the detection of zoonoses will contribute greatly to the identification and control of these pathogens, by increasing the speed of diagnosis, specificity and sensitivity, reproducibility and ease of interpretation. Molecular characterisation studies allow us to distinguish between closely related infectious agents and to document the patterns of transmission of 'strains' and species within populations. This will allow precise determinations to be made about the aetiological agent, its characteristics and the source of infection. This review focuses on recent detection and characterisation techniques for both emerging and re-emerging parasite zoonoses.