Cerebral sparganosis caused by Spirometra mansonoides. Case report

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Cerebral sparganosis presenting with atypical postcontrast magnetic resonance imaging findings: a case report and literature review

Background

Sparganosis, a rare and severe parasitic infection caused by the larvae of Spirometra species or simply sparganum, generally involves subcutaneous tissue or muscle. But occasionally, sparganum can also invade the human brain, resulting in cerebral sparganosis.

Case presentation

A 33-year-old woman presented with a 10-day history of headache. Postcontrast magnetic resonance imaging (MRI) revealed an irregular lesion with enhancement and the tunnel-shaped focus extending to the contralateral hemiphere. Cerebrospinal fluid (CSF) analysis disclosed pleocytosis (166 cells/μL) and an elevated protein concentration (0.742 g/L). Enzyme-linked immunosorbent assay (ELISA) revealed positive sparganum-specific antibody in both blood and CSF. Finally, the diagnosis of cerebral sparganosis was comfirmed. She received praziquantel treatment and got a favorable outcome during six-month follow-up.

Conclusions

Irregular enhancement and the tunnel sign that extends to the contralateral hemisphere on postconstrast MRI are unusual presentations of cerebral sparganosis. ELISA for sparganum-specific antibody can help confirm the diagnosis. Although surgery is the preferred treatment for cerebral sparganosis, praziquantel might also achieve satisfying outcomes.

Human sparganosis, a neglected food borne zoonosis

Human sparganosis is a food borne zoonosis caused by the plerocercoid larvae (spargana) of various diphyllobothroid tapeworms of the genus Spirometra. Human infections are acquired by ingesting the raw or undercooked meat of snakes or frogs, drinking untreated water, or using raw flesh in traditional poultices. More than 1600 cases of sparganosis have been documented worldwide, mostly in east and southeast Asia. Sporadic cases have been reported in South America, Europe, and Africa, and several cases have been described in travellers returning from endemic regions. Epidemiological data suggest that the increased effect of sparganosis on human health is because of greater consumption of raw meat of freshwater frogs and snakes. This Review provides information about the Spirometra parasites and their lifecycles, summarises clinical features, diagnosis, and treatment of human sparganosis, and describes geographical distribution and infection characteristics of Spirometra parasites in host animals.

Difficulty in diagnosing a case with apparent sequel cerebral sparganosis

BACKGROUND

We report on a case of cerebral sparganosis that was correctly identified by a biopsy 10 years after the initial infection.

CASE DESCRIPTION

A 62-year-old man presented with an unusual case of cerebral sparganosis mansoni. He was admitted to our hospital for removal of a right frontal meningioma. Computed tomographic scan and MRI of the brain showed atrophy of the left cerebral hemisphere, enlargement of the lateral ventricle, and several small ring-enhanced lesions in the left frontal lobe. The patient had suffered from motor aphasia and right hemiparesis for 10 years; in addition, he had been treated for cerebral infarction. We performed a left frontal biopsy, during which we also removed the meningioma. The histologic diagnosis was cerebral sparganosis mansoni.

CONCLUSIONS

The follow-up CT findings after the patient's first attack were thought to be characteristic of cerebral sparganosis mansoni. However, the radiographic findings were difficult to differentiate from those of neoplasias.

Neuroimaging and pathological findings in a child with cerebral sparganosis

The authors report the case of a 6-year-old boy with cerebral sparganosis due to infection with a plerocercoid tapeworm larva of Spirometra mansoni. Magnetic resonance imaging revealed an area of irregular long T2 signal in the right frontal lobe. When compared with images obtained 2 years earlier, the lesion appeared to have migrated into the parietal lobe. During surgery for the removal of a granuloma, the parasite was discovered and excised. Following surgery, the patient's neurological deficits markedly improved. The authors review the pathological and imaging features of cerebral sparganosis.

Neuroparasitic infections: cestodes, trematodes, and protozoans

Parasitic infection of the nervous system can produce a variety of symptoms and signs. Because symptoms of infection are often mild or nonspecific, diagnosis can be difficult. Familiarity with basic epidemiological characteristics and distinguishing radiographic findings can increase the likelihood of detection and proper treatment of parasitic infection of the nervous system. This article discusses the clinical presentation, diagnosis, and treatment for some of the more common infections of the nervous system caused by cestodes, trematodes and protozoans: Echinococcus spp., Spirometra spp. (sparganosis), Paragonimus spp., Schistosoma spp., Trypanosoma spp., Naegleria fowlerii, Acanthamoeba histolytica, and Balamuthia mandrillaris.

Testicular sparganosis in a child from Uruguay

A patient 9 years old had a painless tumor in the left testicle. The left testicle measured about 5 cm long and about 3 cm wide and was stony hard in part. From an echographic image, the patient was diagnosed to have a hematoma in the left testicle. The left testicle was surgically removed. From histological observations, burrows were surrounded by numerous eosinophils in the testicle, epididymis and tunica vaginalis. Cross sections of spargana were in the burrows. Severe granulomatous orchitis and epididymitis were around the burrows. This case was the second one of human sparganosis in Uruguay.

Intraventricular haemorrhage and hydrocephalus caused by intraventricular parasitic granuloma suggesting cerebral sparganosis

A 67-year-old female farmer presented with acute loss of consciousness. Computed tomograms showed a calcified mass in the cavum septi pellucidi with intraventricular haemorrhage and obstructive hydrocephalus. The patient became fully conscious after urgent external ventriculostomy and subsequently underwent craniotomy for the excision of the mass. Pathological examination of the mass demonstrated a granuloma surrounding a degenerating larva compatible with Spirometra mansonoides whose mimicking an intraventricular tumour has not been reported before.

Cerebral sparganosis in an East Timorese refugee

OBJECTIVE

To report the first case of cerebral sparganosis diagnosed in Australia.

CLINICAL FEATURES

A 23-year-old East Timorese refugee, whose diet before migration included raw snakes and frogs, presented with a generalised tonic-clonic seizure and a nine-month history of episodic left hemianaesthesia. Computerised axial tomography of the brain showed a right frontal lesion, which was excised, and histological examination demonstrated changes typical of sparganosis.

INTERVENTION AND OUTCOME

Excision of the lesion resulted in cure. Postoperative eosinophilia and a subcutaneous nodule presumed to be due to disseminated sparganosis resolved following a course of praziquantel.

CONCLUSION

Clinicians should consider the possibility of unusual parasitic infections in refugees who present with intracranial space-occupying lesions, especially those from developing countries. A dietary history may aid the diagnosis.

Cerebral sparganosis diagnosed and treated with stereotactic techniques. Report of two cases

Infestation of the central nervous system with sparganum, the larva of Spirometra mansoni, is rare. Only 27 cases have been reported in the literature; however, the true incidence might be underestimated. Two cases are reported that were definitively diagnosed by stereotactic biopsy techniques. Without a positive histological diagnosis, the first case would have been diagnosed as having a metastatic brain tumor and a course of radiotherapy would probably have been initiated. Differentiation between granuloma of cerebral sparganosis and brain tumors such as meningiomas, gliomas, and metastatic tumors is often difficult before operation. Detailed magnetic resonance imaging might offer some help in such cases. Emphasis is placed on the increasing importance of stereotactic surgery in the diagnosis and treatment of an intracerebral mass lesion, including cerebral sparganosis.