Human cysticercosis: parasitology, pathology, clinical manifestations and available treatment

Transventricular endoscopic approach to the anterior interhemispheric fissure for neurocysticercosis: illustrative cases

BACKGROUND

Neurocysticercosis (NCC) is a global public health problem. It is a complex disease to manage and a cause of great morbidity and mortality in affected patients. Conventional surgical approaches have been used for many years, but currently, minimally invasive approaches are being used with good results. The authors present a case of NCC in the anterior interhemispheric fissure that was treated with a transventricular endoscopic approach.

OBSERVATIONS

A 32-year-old male patient was admitted for persistent moderate headache and dizziness. Gadolinium-enhanced magnetic resonance imaging (MRI) showed multiple parenchymal, ventricular, and subarachnoid cystic lesions, especially in the anterior interhemispheric space. A transventricular endoscopic approach was selected and applied. There were no complications during surgery. Pathological analysis confirmed the diagnosis of NCC. Control MRI demonstrated the absence of cysts in the anterior interhemispheric space.

LESSONS

Minimally invasive approaches are an excellent alternative for patients with NCC, especially if a patient requires more than one surgery.

The activity of drug-metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm Hymenolepis diminuta

The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta, a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminuta are able to reduce the carbonyl group of flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.

Prevalence, predilection sites and pathological findings of Taenia multiceps coenuri in slaughtered goats from south-east Iran

Coenurosis is a zoonotic disease in a variety of ruminants caused by the metacestode of Taenia multiceps. The coenuri in the brain and spinal cord of sheep and goats have been identified as Coenurus cerebralis whilst those reported in other tissues have been named Coenurus gaigeri. This study was conducted during the spring and summer of 2011. Out of 25 739 goats inspected in slaughterhouses, 23 carcasses (0.09%) revealed one or multiple visible swellings on the different muscles and visceral organs. The coenuri, of variable sizes, were found mainly in the muscles of the thigh, shoulder and neck, and were less common in the abdominal muscles and subcutaneous tissues. Coenuri were also found in the diaphragm, tongue, intercostal muscles, lung, parotid area and tunica adventitia of the aorta in a goat with severe infection. The brains of slaughtered goats that had coenuri in their skeletal muscles were examined and coenuri were found in two specimens (8.69%). The coenuri were located in the occipital lobe, the anterior part of the right cerebrum and the parietal lobe of the left cerebrum. Histopathologically, coenuri in the brain caused pressure atrophy and liquefactive necrosis in the surrounding tissues, hyperaemia, perivascular cuffing, neuronal degeneration, neuronophagia, satellitosis, diffuse microgliosis and astrocytosis. Coenuri in the skeletal muscles caused degenerative and necrotic changes, hyalinisation and myositis. In the lung, tissues around the coenurus revealed atelectasis and focal interstitial fibrosis. In the present study, concurrent occurrence of coenuri in the central nervous system and skeletal muscles supports the hypothesis that C. cerebralis and C. gaigeri are different names for the metacestodes of the same species of tapeworm.

Serum and cerebrospinal fluid S100B concentrations in patients with neurocysticercosis

The clinical manifestations of neurocysticercosis (NC) are varied and depend on the number and location of cysts, as well as on the host immune response. Symptoms usually occur in NC when cysticerci enter a degenerative course associated with an inflammatory response. The expression of brain damage markers may be expected to increase during this phase. S100B is a calcium-binding protein produced and released predominantly by astrocytes that has been used as a marker of reactive gliosis and astrocytic death in many pathological conditions. The aim of the present study was to investigate the levels of S100B in patients in different phases of NC evolution. Cerebrospinal fluid and serum S100B concentrations were measured in 25 patients with NC: 14 patients with degenerative cysts (D), 8 patients with viable cysts (V) and 3 patients with inactive cysts. All NC patients, except 1, had five or less cysts. In most of them, symptoms had been present for at least 1 month before sample collection. Samples from 8 normal controls (C) were also assayed. The albumin quotient was used to estimate the blood-brain barrier permeability. There were no significant differences in serum (P = 0.5) or cerebrospinal fluid (P = 0.91) S100B levels among the V, D, and C groups. These findings suggest that parenchymal changes associated with a relatively small number of degenerating cysts probably have a negligible impact on glial tissue.

Neurocysticercosis: a review

BACKGROUND

In North America, the largest number of neurosurgical cases stemming from parasitic infections involves the larval form of Taenia solium, the infectious organism causing neurocysticercosis. This infection of the central nervous system (CNS) is most commonly seen in areas with significant immigrant populations and can often present particular challenges to treating physicians.

METHODS

A review of the literature was performed, highlighting the epidemiology, parasitology, and clinical manifestations of neurocysticercosis. Particular attention was paid to 4 locations of neurocysticercosis lesions: parenchymal, subarachnoid/cisternal, intraventricular, and spinal.

RESULTS

Both medical and surgical interventions may be necessary for adequate treatment of neurocysticercosis, depending on various factors, including location of lesion.

CONCLUSIONS

A review of neurocysticercosis, with particular attention paid to location of disease involvement in the CNS, provides important information to the clinical management of this disease.

Correlative MR imaging and histopathology in porcine neurocysticercosis

PURPOSE

To examine whether all the histopathologically seen features of cysticercus cysts excised from brain of swine naturally infected with neurocysticercosis during its evolution are actually visible on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Five swine naturally infected with cerebral cysticercosis were subjected to fast spin-echo (SE) T2, SE T1, fluid attenuated inversion recovery imaging, T1-weighted magnetization transfer (MT), and postcontrast T1-weighted MT sequences on MRI. These animals were sacrificed after imaging and ex vivo imaging of the intact excised brain using the same imaging protocol was also performed. Grossing of these brains was done similar to the ex vivo imaging planes. Numeral density and external appearance of each cyst and scolex were evaluated on each pulse sequence. Amount of pericystic edema, if present, was also assessed. On histopathology, cellular characteristics, inflammatory response, and the extent of edema, if present, in the brain parenchyma around the cysts were graded. Cysts were categorized into viable, early, and late degenerated on histopathology. The MRI features of each cyst were correlated with their histopathologic findings.

RESULTS

Out of 31 cysts, eight were found to be viable, 13 early degenerated, and 10 late degenerated on histopathology. T2-weighted imaging demonstrated all the cysts while T1-weighted imaging showed 97% of the cysts. Scolex was seen in 90.3% and 93.5% of the cysts on T2- and T1-weighted images, respectively. Minimal edema (grade I) and inflammation in degenerating cysts present on histopathology was not visible on MRI. All but one of eight degenerated cysts, which showed enhancement on postcontrast MRI, had edema on imaging as well as on histopathology.

CONCLUSION

T2-weighted MRI demonstrated all the cysts that were visible on histopathology. Non-enhancement of some of the degenerated cysts along with absence of edema on MRI is likely to underestimate the staging of neurocysticercosis evolution, and these early degenerating cysts may be misdiagnosed as in viable stage.

Neuron-specific enolase in patients with neurocysticercosis

BACKGROUND

Neurocysticercosis (NC) is the most frequent parasitic disease of the human nervous system. Its clinical manifestations are varied and depend on the number and location of cysts, as well as the host immune response. Symptoms in NC usually occur when cysts enter into a degenerative phase associated with perilesional inflammation. We speculate that neuron-specific enolase (NSE)--a marker of neuronal injury--could be elevated in patients with degenerating cysts comparing to those with viable cysts.

METHODS

We examined serum NSE (sNSE) and cerebrospinal fluid (CSF) NSE (cNSE) levels in 25 patients with NC: 14 patients with degenerative cysts (D), 8 patients with viable cysts (V) and 3 patients with inactive cysts. Samples of eight normal controls (C) were also obtained. Determination of albumin was performed in serum and CSF samples, and the CSF/serum albumin ratio (albumin quotient, Q(alb)) was used to estimate the blood-brain barrier permeability.

RESULTS

All patients, with the exception of one case, had five or less cysts. Comparisons between V, D and C groups did not demonstrate significant differences of cNSE, Q(alb) and sNSE levels. Further, there were no significant differences of cNSE and sNSE levels between patients with or without intracranial hypertension (ICH).

CONCLUSIONS

These findings suggest that the inflammatory response associated with a relatively small number of degenerating cysts does not provoke significant neuronal damage. Further studies considering patients with a larger number of cysts will be required to assess if there is evidence of neuronal damage in such more severe cases.

Chemotherapy of porcine cysticercosis with albendazole sulphoxide

Cysticercosis is a zoonotic disease of humans produced by the larval stage of swine parasite, Taenia solium. Chemotherapy of infected pigs is a possible strategy for avoiding disease transmission and improving health programs in endemic areas of cysticercosis. In this preliminary study, seven naturally infected pigs from 6 to 12 months of age were allotted to treated (n = 4) and control groups (n = 3). The treated animals received a subcutaneous injection in their forelegs and thighs of 15 mg/kg per body weight of albendazole sulphoxide (ABZSO; Pisa, Mexico) once per day for 8 days. At the same time, the control group received a subcutaneous injection of saline solution (9% NaCl). After 12 weeks, all the animals were slaughtered and at least 200 metacestodes were isolated from the muscles and brain of each animal. Using histology and the metacestode viability criteria described in this study, treated animals had no viable cysts in their muscle (0/200), while 7 of 17 (41.1%) viable cysts were observed in those isolated from their brains. In the control group, 183/200 (91.5%) muscle metacestodes were viable and from brain, 22/29 (75.8%) metacestodes were viable. The 15 mg/kg per body weight dosage of ABZSO was 100% effective against muscular cysticercosis as shown by the lack of viable cysts and the micro-calcifications in meat from the treated pigs.

Taenia solium metacestode viability in infected pork after preparation with salt pickling or cooking methods common in Yucatán, Mexico

The cestode parasite Taenia solium is an important cause of foodborne infection throughout tropical and subtropical regions. Ingestion of pork meat infected with T. solium larvae can lead to taeniasis infection in humans. With tourism and the consumption of native food increasing, it is important to investigate potential risks of transmission associated with food preparation methods. In this study, traditional Mexican salt pickling and two methods of pork preparation (as roast pork [cochinita pibil] and in pork and beans [frijol con puerco]) were evaluated in order to determine their effects on T. solium cyst viability in infected tissue. In the control groups, all metacestodes isolated were 100% viable, and only small changes in pH (from 6.0 to 5.9) and temperature (29 to 30 degrees C) were recorded. No viable cysts were detected after 12 and 24 h of salt pickling. The pH of the meat during salting dropped from 6.0 to 5.3. Osmotic changes and dehydration from the salting, rather than a change in pH, could be considered the main cause of cyst death. Temperatures of >65 degrees C damaged T. solium metacestodes in roast pork and in pork and beans. The results of this study indicate that if traditional pork dishes are prepared properly, T. solium cysts are destroyed. The criteria used in this study to evaluate the viability of tissue cysts are discussed.

Cysticercosis in Nepal: a histopathologic study of sixty-two cases

Human cysticercosis, an infection caused by larvae of Taenia solium, is a major public health problem in many developing countries. Sixty-two of 23,402 biopsy cases have been detected as cysticercosis in the last 5 years in Patan Hospital. Most (82%) of the patients presented with solitary skin nodules, another 10% with nodules in the oral mucosa, and 8% in the breast. Forty cases were identified from the Kathmandu valley and the rest from outside Kathmandu. Most patients were younger than 30 years of age (mean, 21+/-11 years). Statistically, there was no difference between males (0.28%) and females (0.24%). The average size of cysticercosis was 19 mm in diameter, and the histology of cysticercosis showed fibrous walled cysts covered by several layered epithelioid cells with a few Langhans' giant cells and infiltration of eosinophils without caseous necrosis. These cysticercosis findings from an endemic area will be helpful for doctors who examine immigrant patients in nonendemic areas.

Neurocysticercosis

Neurocysticercosis is the most common parasitic disease of the central nervous system. Varied clinical manifestations occur, due to deposition of larvae of the parasite Taenia solium in cerebral parenchyma, meninges, spinal cord, muscles, eyes and skin. The diagnosis of neurocysticercosis can be made with a fairly high degree of accuracy with the help of computed tomography and magnetic resonance imaging. Serological tests and histopathological examination of subcutaneous nodules provide additional support in establishing the diagnosis. The anticysticercal drugs albendazole and praziquantel have been extensively used, and found to be effective for all types of neurocysticercosis. However, recently controversy has been raised about their safety, and long-term clinical usefulness. Preventive health measures, such as provision of safe drinking water and excretion disposal, still offer the best ways to manage this disease.

Methimazole-mediated enhancement of albendazole oral bioavailability and anthelmintic effects against parenteral stages of Trichinella spiralis in mice: the influence of the dose-regime

The influence of methimazole (MTZ) inhibitor of the microsomal oxidases on the systemic availability of the albendazole sulpho-metabolites (ABZS-MT) albendazole-sulphoxide (ABZSO) and albendazole-sulphone (ABZSO2) and on its anthelmintic effects was investigated in a mouse model for helminthic infections. Plasma concentrations of the ABZS-MT were measured by high performance liquid chromatography (HPLC) following treatment of Swiss CD-1 mice with albendazole (ABZ) alone or ABZ plus MTZ, at both single and repeated doses. The anthelmintic effects were assessed in age-matched mice similarly treated following infection with Trichinella spiralis. MTZ significantly (p < 0.01) increased the ABZS-MT plasma concentrations although the pharmacokinetic profile varied greatly according to the dose of ABZ administered. When ABZ was given at a single dose of 50 mg/kg followed by MTZ at 3 mg/kg, a cumulative effect was observed in the ABZS-MT plasma levels with pharmacokinetic parameters (Tmax = 24 h, Cmax= 30.88 microg/ml and AUC = 1120.80 microg h/ml) significantly ( p < 0.01) higher than those following administration of ABZ alone (Tmax = 3 h, Cmax = 11.00 microg/ml and AUC = 268.03 microg h/ml). This cumulative effect was absent following administration of ABZ at 100 mg/kg where, after reaching a maximum (Cmax = 27.23 microg/ml) at 3 h post-administration (Tmax), the ABZS-MTplasma levels felt down quickly to values under those obtained after administration of ABZ at the same dose, but alone (AUC = 362.15 microg h/ml vs. 340.15 microg h/ml, respectively). When ABZ was given at 50 mg/kg together with MTZ three times every 24 h, a rapid decrease was observed in the ABZS-MT plasma levels following administration of both the second and third doses, respectively. The pharmacokinetic profile of ABZS-MT following administration of each of the three doses of ABZ at 100 mg/kg plus MTZ was the same as that obtained after the single treatment. The rapid decrease of the ABZS-MT plasma levels observed after the sustained treatment or after the single treatment at 100 mg/kg could be due to a microsomal oxidase inductive effect (probably the cytochrome P-450) caused by ABZSO. The co-administration of MTZ significantly (p < 0.01) increased the anthelmintic effects of ABZ against both migrating and encysted larvae of T. spiralis. Repeated treatment did not improve the anthelmintic effects of the single treatment as the efficacies against both stages of the parasite were always lower or identical to those of the single treatment at the corresponding doses.