Neglected Parasitic Infections: What Family Physicians Need to Know-A CDC Update

Chagas disease, cysticercosis, and toxoplasmosis affect millions of people in the United States and are considered neglected parasitic diseases. Few resources are devoted to their surveillance, prevention, and treatment. Chagas disease, transmitted by kissing bugs, primarily affects people who have lived in Mexico, Central America, and South America, and it can cause heart disease and death if not treated. Chagas disease is diagnosed by detecting the parasite in blood or by serology, depending on the phase of disease. Antiparasitic treatment is indicated for most patients with acute disease. Treatment for chronic disease is recommended for people younger than 18 years and generally recommended for adults younger than 50 years. Treatment decisions should be individualized for all other patients. Cysticercosis can manifest in muscles, the eyes, and most critically in the brain (neurocysticercosis). Neurocysticercosis accounts for 2.1% of all emergency department visits for seizures in the United States. Diagnosing neurocysticercosis involves serology and neuroimaging. Treatment includes symptom control and antiparasitic therapy. Toxoplasmosis is estimated to affect 11% of people older than six years in the United States. It can be acquired by ingesting food or water that has been contaminated by cat feces; it can also be acquired by eating undercooked, contaminated meat. Toxoplasma infection is usually asymptomatic; however, people who are immunosuppressed can develop more severe neurologic symptoms. Congenital infection can result in miscarriage or adverse fetal effects. Diagnosis is made with serologic testing, polymerase chain reaction testing, or parasite detection in tissue or fluid specimens. Treatment is recommended for people who are immunosuppressed, pregnant patients with recently acquired infection, and people who are immunocompetent with visceral disease or severe symptoms.

Transcriptome profiling of Cysticercus Pisiformis provides insight into responses to host bile acids

Bile acids in host intestine activate larvae of tapeworms and facilitate its invasion. However, the mechanism underlying this process is poorly understood. In order to better understand responses of tapeworms to host biles, we used RNA-Seq profiling method to study the transcriptomes of Cysticercus Pisiformis (larvae of Taenia Pisiformis) after host bile acid treatment. A total of 338.32 million high-quality clean reads were obtained by Illumina Hiseq platform. Totally, 62,009 unigenes were assembled, 38,382 of which were successfully annotated to known databases. A total of 9324 unigenes were identified as differentially expressed genes (DEGs), of which 5380 and 3944 genes were up- and down-regulated in the group treated with bile acids, respectively. Gene Ontology analysis revealed that biosynthesis and energy metabolism potential were significantly strengthened after host bile treatment in C. pisiformis. Similarly, KEGG pathway analysis revealed an enrichment of pathways related to lipid metabolism and carbohydrate metabolism. Among them, 'AMPK signaling pathway' which is critical in balancing cellular energy, was significantly enriched after bile acids activation. In addition, pathways of 'Fatty acid biosynthesis', 'Fatty acid elongation', 'Starch and sucrose metabolism', and 'glycolysis gluconeogenesis' were also significantly changed after bile acid treatment. qRT-PCR analysis confirmed the differential abundances of some key genes in these pathways. Our data suggest that host bile acids remarkably promote the pathways of energy metabolism of this parasite and regulate the genes involved in balancing lipid metabolism and carbohydrate metabolism. These findings provide new insights on the lifecycle of Taenia parasites.

Historical perspective: The British contribution to the understanding of neurocysticercosis

Neurocysticercosis, or brain infestation with the larval stage of Taenia solium, is the most common risk factor for epilepsy in many endemic regions of the world. Hardly any cases are seen in Western developed countries, including Britain. However, a sizeable number (n = 450) was seen among British soldiers returning from deputation to India, then a British colony, first reported by Col. MacArthur at the Queen Alexandria Military Hospital in 1931. Here, we review the influence of the perceptive observations of British Army medics on the understanding of the parasitic disorder. The majority of these people presented with epilepsy. Among the contributions of the army medics were establishing the diagnosis, initially by histological examination of subcutaneous and muscular infestation, and later by radiography, clarifying the prognosis and the role of medical and surgical treatments and uncovering the close relationship between the larval (cysticercosis) and adult (intestinal tapeworm) stages of T. solium.

Mathematical model of the life cycle of taenia-cysticercosis: transmission dynamics and chemotherapy (Part 1)

BACKGROUND

Taenia solium is the aetiological agent of human taeniasis, pig cysticercosis and human neurocysticercosis, which are serious public health problems, especially in developing countries.

METHODS

A mathematical model of the transmission dynamics of taeniasis-cysticercosis is formulated. The model consists of a coupled system of differential equations, which are density-dependent equations for describing the flow of the parasite through the life cycle. The model is hybrid since it comprises deterministic equations with stochastic elements which describe changes in the mean parasite burden and incorporates the overall pattern of the parasites' distribution.

RESULTS

Sensitivity and bifurcation analyses were carried out to determine the range of values of the model. The model can reproduce the observed epidemiological patterns of human taeniasis, pig and human cysticercosis. For example, for a wide range of parameter values, the mean intensity of adult worms tends to rapidly stabilize in one parasite per individual host. From this model, we also derived a Susceptible-Infected model to describe the prevalence of infection in humans and pigs. Chemotherapeutic interventions against pig cysticercosis or human taeniasis may reduce rapidly and effectively the mean intensity of human taeniasis, pig cysticercosis and human cysticercosis. This effect can be achieved even if the protective efficacy of the drug is of the order of 90% and the coverage rate is 90%. This means that health in humans infected either with adult worms or cysticerci may be achieved by the application of anthelmintic drugs against pig cysticercosis. However, treatment against human cysticercosis alone, does not influence neither human teniasis nor pig cysticercosis. This is because human cysticercosis infection does not influence the value of the basic reproductive number (Ro).

CONCLUSIONS

Even coverage of 100% in the administration of anthelmintics did not eliminate the infection. Then elimination of the infection in all hosts does not seem a feasible goal to achieve by administering only chemotherapeutic interventions. Throughout the manuscript a discussion of our model in the context of other models of taeniasis-cysticercosis is presented.

Helminth infection alters mood and short-term memory as well as levels of neurotransmitters and cytokines in the mouse hippocampus

Helminthic infections are important causes of morbidity and mortality in many developing countries, where children bear the greatest health burden. The ability of parasites to cause behavioral changes in the host has been observed in a variety of host-parasite systems, including the Taenia crassiceps-mouse model. In murine cysticercosis, mice exhibit a disruption in the sexual, aggressive and avoidance predator behaviors.

OBJECTIVE

The present study was conducted to characterize short-term memory and depression-like behavior, as well as levels of neurotransmitters and cytokines in the hippocampus of cysticercotic male and female mice.

METHODS

Cytokines were detected by RT-PCR and neurotransmitters were quantified by HPLC.

RESULTS

Chronic cysticercosis infection induced a decrease in short-term memory in both male and female mice, having a more pronounced effect in females. Infected females showed a significant increase in forced swimming tests with a decrease in immobility. In contrast, male mice showed an increment in total activity and ambulation tests. Serotonin levels decreased by 30% in the hippocampus of infected females whereas noradrenaline levels significantly increased in infected males. The hippocampal expression of IL-4 increased in infected female mice, but decreased in infected male mice.

CONCLUSION

Our study suggests that intraperitoneal chronic infection with cysticerci in mice leads to persistent deficits in tasks dependent on the animal's hippocampal function. Our findings are a first approach to elucidating the role of the neuroimmune network in controlling short-term memory and mood in T. crassiceps-infected mice.

Neurocysticercosis

Cysticercosis is an infection caused by Taenia solium larvae (cysticerci). When the cysticercus is lodged in the central nervous system (CNS), the disease is known as neurocysticercosis (NCC). NCC is the most frequent and most widely disseminated human neuroparasitosis. It is endemic in many parts of the world, particularly Latin America, Africa, and Asia, and still relatively frequent in Portugal, Spain and Eastern European countries It is also endemic in developed countries with high rates of immigration from endemic areas. Man may act as an intermediate host after ingestion of mature, viable T. solium eggs via the fecal-oral route. The development of lesions in the brain and leptomeninges, and the consequent of onset of symptoms associated with NCC are mainly due to the host immune-inflammatory response. As long as the cysticercus remains viable, there is relative host immune tolerance. It is only when the parasite dies that massive antigen exposure occurs, with intensification of the immune response/inflammatory reaction and the appearance or worsening of symptoms. NCC can be asymptomatic or cause widely varied clinical manifestations, such as seizures, increased intracranial pressure, ischemic cerebrovascular disease, dementia, and signs of compression of the spinal roots/cord. The combination of two or more symptoms is common. Such clinical polymorphism is determined by 1) the number of lesions (single or multiple cysticerci); 2) the location of CNS lesions (subarachnoid, intracerebral, intraventricular, intramedullary); 3) the type of cysticercus (Cysticercus cellulosae, Cysticercus racemosus); 4) the stage of development and involution of the parasite (vesicular or viable, necrotic, fibrocalcified nodule); and 5) the intensity of the host immune-inflammatory response (no inflammatory reaction, leptomeningitis, encephalitis, granular ependymitis, arteritis).

Cysticercosis of temporalis muscle: an unusual cause of temporal headaches. A case report

Cysticercosis is a common parasitic infection caused by encysted larvae of the helminth Taenia solium (pork tapeworm). The central nervous system (CNS) is the most important primary site of infection and the disease can present with solitary or multiple space occupying lesions. Less common presentations in the CNS include the racemose variety with macroscopic groups of cysticerci in the subarachnoid space giving the appearance of a cluster of grapes and basal or ventricular cysticercosis causing obstructive hydrocephalus. Involvement of other organs: skeletal muscle, eyes, myocardium and the lungs has also been reported. Cases of cysticercosis presenting as isolated muscle mass (pseudotumours) without involvement of the CNS have also been recently described in the literature. We present a case of a 43-year-old woman who complained of subacute onset of left temporal pain and headache. Magnetic resonance imaging (MRI) showed characteristic imaging findings suggestive of cysticercosis of the temporalis muscle.

Impact of naturally acquired Taenia solium cysticercosis on the hormonal levels of free ranging boars

In chronically infected BALBc/AnN male mice, Taenia crassiceps cysticercosis induces changes in the host's sex steroids hormone that lead to their estrogenization and deandrogenization, with possible repercussions on their susceptibility to infections. Here reported are the serum steroid levels in free range cysticercotic male boars. Therefore, the possible effects of Taenia solium cysticerci over the pig steroid levels were evaluated. Herein are described the sex steroids and cortisol levels of non-cysticercotic (n=25) and cysticercotic (n=22) adult boars, as diagnosed by tongue inspection, all free-ranging in a typical village of an endemic rural area in Mexico. A significant reduction of testosterone (P=0.022) and a likely one of 17beta-estradiol (P=0.08) levels were found in the cysticercotic boars in comparison with those non-cysticercotic, whilst no significant differences in the cortisol and DHEA levels were detected. Serum levels of specific antibodies did not correlate with infection nor with the levels of any of the hormones measured. Results suggest that T. solium cysticercosis significantly affects the hormonal status of its porcine host independently of their antibody response.

Balb/Cj Male Mice Do Not Feminize after Infection with Larval Taenia crassiceps

Balb/cJ mice fail to mount an immune response capable of clearing infection with larval Taenia crassiceps. Additionally, male Balb/cJ mice display a lag in larval growth of approximately 3 wk as compared to growth in female mice. It has been reported that male Balb/ cAnN mice generate a protective immune response early in infection, and become permissive to larval growth after they feminize (200-fold increase in serum estradiol and 90% decrease in serum testosterone). To determine if a different strain of Balb/c mice (Balb/cJ) also feminize, serum was collected from infected male mice for 16 wk and levels of 17-beta-estradiol and testosterone were measured via ELISA. In addition, the mounting responses of 12- and 16-wk infected male mice, as well as uninfected control mice, were determined after isolation with a female mouse. The results of these experiments show that male Balb/cJ mice do not feminize during infection with larval T. crassiceps. There was no significant change in serum levels of either 17-beta-estradiol or testosterone during the course of infection (> 16 wk). Moreover, there was no significant decrease in the number of times infected male mice mounted the female mouse as compared to uninfected controls. These results suggest that there may be variances between the substrains of Balb/c mice that lead to the phenotypic differences reported for male Balb/cJ and Balb/cAnN mice.

Short report: Evidence and potential for transmission of human and swine Taenia solium cysticercosis in the Piracuruca region, Piauí, Brazil

The study conducted in the Cocal dos Alves municipality, located in the Piracuruca region of Piauí State, Brazil in November of 2003 was based on both a socio-behavioral survey and analysis of serum antibodies and parasitic materials. Pig raising is the main economic activity with 91.4% using extensive farming. On the studied population, 54.3% of people did not apply any sanitary measures to wastewater, 45.7% used septic tanks, and 69.1% consumed water without treatment. The data collected indicated the occurrence and active transmission of the taeniasis-cysticercosis complex in the region. One of seven voluntary persons was positive in antibody-ELISA tests using both native and recombinant antigens. Multiplex PCR and DNA sequencing of cyst samples obtained from a pig revealed the presence of the Afro-American genotype of Taenia solium. This study revealed the occurrence of human and porcine cysticercosis in the Piracuruca region of Piauí State, middle-north of Brazil.

PROINFLAMMATORY CYTOKINES IN GRANULOMAS ASSOCIATED WITH MURINE CYSTICERCOSIS ARE NOT THE CAUSE OF SEIZURES

Neurocysticercosis is a parasitic infection of the human central nervous system caused by the cestode Taenia solium. The most common clinical manifestations of neurocysticercosis are seizures. Taenia crassiceps cysticercosis in mice has been used as an experimental model for T. solium cysticercosis. Granulomas surrounding murine cysticerci have striking immunopathological resemblance to human neurocysticercosis; early stage granulomas were able to induce seizures in a rodent model. To assess the role of proinflammatory cytokines in early stage granulomas, we isolated RNA from murine cysticercal granulomas and checked for cytokine expression by reverse transcriptase-polymerase chain reaction (RT-PCR) and/or ribonuclease (RNase) protection assays. Cytokine expression was compared with histological stages. Interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist, and tumor necrosis factor (TNF-alpha) were the major cytokines detected in all granulomas. Signals for IL-12, IL-18, and IL-6 RNA were not consistently detected and, when detected, were barely demonstrable. Expression of migration inhibitory factor (MIF), IL-6, IL-1alpha, TNF-alpha, and IL-18 was not significantly different between early and late-stage granulomas. Expression of IL-1beta, IL-1 receptor antagonist, and IL-12 p40 were higher in late, compared with early, stages. Thus, we demonstrated a broad range of cytokines in these granulomas. However, we did not document preferential expression of any proinflammatory cytokines in early stage granulomas. Thus, proinflammatory cytokines are not responsible for the seizures in the rodent model of neurocysticercosis.

Usefulness of severe combined immunodeficiency (scid) and inbred mice for studies of cysticercosis and echinococcosis

The topics in this review are the usefulness of immunodeficient and inbred mice for studies of developmental biology, drug efficacy and host specificity in cysticercosis and echinococcosis. In non-obese diabetic severe combined immunodeficiency (NOD/Shi-scid) mice of both sexes, in vitro hatched oncospheres of all three human taeniid species (Taenia solium, Taenia saginata and Taenia asiatica) developed into cysticerci comparable to or bigger than those developed in their known intermediate host animals, whereas only females were susceptible to these infections in other scid mice of BALB/c, C57BL or C.B-17 inbred strains. Detailed morphological observation from post-oncospheral to cysticercus developmental stages is expected to be easy when we use NOD/Shi-scid mice experimentally inoculated with in vitro hatched oncospheres. Metacestocidal effect of oxfendazole was evaluated in NOD/Shi-scid mice experimentally inoculated with oncospheres of T. solium. In Echinococcus multilocularis infection, larval tissue proliferated without induction of inflammatory host responses in scid mice, thus facilitating isolation of the larval vesicles and protoscoleces for biochemical and molecular biological studies. Trans portal inoculation of metacestode tissues resulted in proliferation of secondary echinococcal foci localized exclusively in the liver without metastasis to other tissues or organs. The advantages of a mouse model for Echinococcus granulosus are also described.

The role of sex steroids in the complex physiology of the host-parasite relationship: the case of the larval cestode of Taenia crassiceps

Sex steroids play a significant role in regulating the parasite load in experimental intraperitoneal Taenia crassiceps cysticercosis of male and female Balbc/anN mice. Briefly, oestrogens increase parasite loads and androgens decrease them (1) by acting directly on the parasite, favouring or hindering its reproduction, respectively, and (2) by biasing the hosts' immune response towards a parasite-permissive Th2 or a parasite-restrictive Th1 response. The infected male host also undergoes drastic endocrinological and behavioural changes that may impinge upon the course of infection, and the host's mating behaviour and its exposure to predators. In addition, at different times of infection, significant changes occur in the expression of c-fos in the host's hyppocampus, hypothalamus and preoptic area. Thus, the host's brain seems to sense and/ or react to intraperitoneal infection. The physiological domains of the network affected by the infection, which classically included the hypothalamus-pituitary-axis and the immune system, must now incorporate the host's sexual hormones and other areas of the brain. The network's complex circuitry and functions may help understand some basic questions of parasitology (i.e. the hosts' sexual dimorphism in parasite infections, host-parasite specificity, heterogeneity in the course and outcome of infections at different stages of parasite and host development). The plurality of elements and the complexity of the network that regulates the host-parasite relationship also point to additional strategies for the treatment and control of infections.

Cysticercosis of the eye in South India--a case series

PURPOSE

To study the clinical presentation and treatment outcome of patients with ocular cysticercosis in southern India.

METHODS

This study included 10 patients who were diagnosed to have ocular or adnexal cysticercosis over a period of one year in Pondicherry, India. The clinical presentation, results of investigation and treatment outcome of the cases were analysed retrospectively.

RESULTS

Age of these patients ranged from 12 to 55 years. Four presented with loss of vision, two with a swelling in the eyelid, one with proptosis, one with diplopia and two with conjunctival involvement. ELISA for cysticercus antibodies in serum was positive in all cases. Albendazole and prednisolone were given for the treatment of these cases. Two patients responded well to treatment and were completely cured of the disease. There was partial improvement in 6 cases. Surgery in the form of excision was performed in two cases following a course of medical therapy. There was no significant change in visual acuity in eyes with intraocular cysticercosis following treatment.

CONCLUSION

Ultrasonography B scan and ELISA for anticysticercal antibodies help to establish the diagnosis of ocular cysticercosis. A combination of oral albendazole and corticosteroids is found to be effective in confirmed cases. Intraocular cysticercosis is associated with a poor prognosis for vision.

Epileptogenic activity of granulomas associated with murine cysticercosis

Neurocysticercosis, caused by Taenia solium, is a common cause of neurologic disease in developing countries and among immigrants to the United States. Seizures are the most common clinical manifestation of neurocysticercosis. Imaging studies of patients with seizures from neurocysticercosis typically reveal evidence of an inflammatory reaction associated with the parasite or calcified granulomas. This study investigated whether a substance produced by the host granulomatous reaction to the dying parasite, in a mouse model of the infection, is sufficient to induce epileptiform activity. Granulomas associated with Taenia crassiceps cysticerci were removed from the peritoneal cavity of infected mice. One piece of the granuloma was used for blinded histological staging of the dying parasite. The second piece was used to generate extracts, which were injected into the hippocampus of an anesthetized Sprague-Dawley rat. Positive controls included animals injected with kainic acid, picrotoxin, or bicuculline. Seizures were recorded after injection of extracts from 6 out of 6 early stage granulomas, but only 1 out of 9 late stage granulomas. Injections of buffered saline, extracts from non-stimulated mouse spleen cells, and homogenates of viable parasite material caused no epileptiform activity. The data suggest that a substance in the granulomas early in the inflammatory response to the dying parasite is capable of inducing seizure activity. Further experiments are needed to dissect out the exact seizure mediator in the granuloma extracts.

Intraocular cysticercosis: clinical characteristics and visual outcome after vitreoretinal surgery

PURPOSE

To report the clinical characteristics of, discuss the surgical options for, and analyze the factors affecting the anatomic and visual outcome of intraocular cysticercosis.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Forty-five eyes of 44 Indian patients with posterior segment intraocular cysticercosis.

METHODS

The charts of 45 eyes, in which intraocular cysticercosis was removed by vitreoretinal surgery (either transscleral or transvitreal), were reviewed.

MAIN OUTCOME MEASURES

These included the postoperative retinal status and the best-corrected Snellen visual acuity.

RESULTS

Intraocular cysticercosis was present in the vitreous cavity of 27 eyes (60%) and in the subretinal space of 18 eyes (40%). Anterior segment inflammation was seen in 13 eyes (28.8%) and vitreous inflammation in 38 eyes (84.4%). Retinal detachment was observed in 22 eyes (48.8%), with proliferative vitreoretinopathy in 13 eyes (59.09%). Subretinal cysts anterior to the equator (4 eyes) were removed transsclerally, whereas subretinal cysts posterior to the equator and intravitreal cysts (41 eyes) were removed transvitreally. The mean follow-up was 10.5 months. At the last follow-up, the retina was attached in 39 eyes (86.6%); visual acuity of >/=5/200 was achieved in 67.5%.

CONCLUSIONS

Current vitreoretinal surgical techniques enable removal of intraocular cysticercosis in all cases, with reattachment of the retina in 86.6% and recovery of ambulatory vision in approximately 67% of cases.

Taenia crassiceps cysticercosis in mice does not increase the carcinogenic effect of methyl-nitrosourea

An association between brain cysticercosis and malignant neoplasms in humans has recently been reported. To explore the possibility of a potentiating effect of cysticercosis on carcinogenesis mice infected with Taenia crassiceps cysticerci were exposed to the carcinogenic substance methyl-nitrosourea; 35% of them developed lymphoma, in contrast with 50% of control non-infected animals exposed to MNU. In this experimental model of cysticercosis we did not find a potentiating effect of peritoneal cysticercosis on the carcinogenicity of MNU.

The experimental infection of pigs with different numbers of Taenia solium eggs: immune response and efficiency of establishment

Three of 4 pigs inoculated with 10 eggs of Taenia solium became infected. In those pigs infected with larger numbers of eggs, all became infected. Specific antibodies against the metacestodes were found in serum at day 30 postinoculation (PI) in animals that received 1,000 or more eggs and at day 60 in those that received 10 or 100 eggs. The concentration and diversity of antibodies increased up to the day of death in pigs that received 10,000 or 100,000 eggs. All pigs infected with 1,000 or more eggs developed antibodies, but only 40% and 75% of pigs that received 10 and 100 eggs, respectively, developed antibodies. Metacestodes were found in the muscles of 23 of the 27 infected animals. In 35.7% of the pigs that received 1,000 or more eggs, metacestodes were also found in the brain. Most of the metacestodes found in pigs infected with 10 or 100 eggs were caseous, whereas in pigs infected with 1,000 or more eggs the majority of metacestodes were vesicular. This study shows that the severity of T. solium infection and the possible regulation of the immune system-evasion mechanisms depend on the number of metacestodes that succeed in establishing themselves and remain vesicular.

[Ocular cysticercosis]

Ocular cysticercosis results from development of Taenia solium larvae, Cysticercus cellulosae, in the eye. This condition is observed all over the world but is particularly common in developing countries. The eye, like nervous system and muscle tissue, is a prime location for parasitic development because of its rich vascularization. Intraorbital cysticercosis accounts for 75 to 85% of cases and if untreated leads to blindness. Intravitreal involvement is the most common followed by subretinal involvement. Involvement of other structures such as the camera aqueosa, iris, and crystalline lens is rare. Diagnosis of intraocular cysticercosis is straightforward when cysticerci are visible. Immunologic testing of aqueous humor using ELISA, western-blot, or immunodetection of circulating antigens can be useful diagnostic techniques in patients with opacification of the eye. Involvement of the orbit, palpebra, conjunctiva, and lacrimal glands is observed in 20 to 25% of cases. Diagnosis of adnexal involvement is facilitated by ultrasonography and CT-scan. Drug therapy for ocular manifestations of cysticercosis is ineffective and hastens progression of the disease by exacerbating the inflammatory response. Surgical treatment is the only alternative. Significant progress has been made thanks to new microsurgical vitreal and retinal procedures but these techniques are often unavailable in developing countries. The severity of ocular cysticercosis and poor management facilities in developing countries underlines the need for prevention by sanitary measures and health education.

Clinico-pathological studies in cattle experimentally infected with Taenia saginata eggs

Calves 1-2 months old were experimentally infected with eggs of Taenia saginata and clinical and haematological deviations, development and distribution of cysticerci and pathological changes were recorded. The calves infected with 5,000, 10,000 or 50,000 eggs showed an increase in pulse and respiratory rates. The animals that received 50,000 eggs had significantly increased pulse (p < 0.05) and respiratory rates (p < 0.005). The symptoms were more severe in young, 30-day-old calves infected with 50,000 eggs. Haemoglobin concentration, haematocrit values and red blood cell count decreased, but white blood cell count increased slightly. Lymphocytes and eosinophils also increased up to 88% and 14% (p < 0.05), respectively. Most of the cysticerci were not fully formed 1 month post-infection, but at 2 months the cysts were fully mature and at 4 months, some cysts had degenerated. There was no uniform pattern of distribution of cysticerci in the body of infected calves, but the most commonly affected sites were masseter and heart muscles, followed by diaphragm, tongue and other skeletal muscles. The maximum concentration of 8-14 cysticerci per 10 g of tissue was recorded in masseter muscles and heart. The affected parts revealed tissue reactions that included pressure atrophy, necrosis and fibrosis. Microscopically, the lesions comprised infiltration with lymphocytes, plasma cells, eosinophils and macrophages, fibrosis, necrosis and calcification. The tissue reaction was severe in calves infected with 50,000 eggs. The severity of clinical signs, haematological and pathological changes depended mostly on the age of the animals and dose of infection.

Clinical characteristics, seizure spread patterns and prognosis of seizures associated with a single small cerebral calcific CT lesion

Clinical characteristics of 97 patients with epilepsy associated with a small single cerebral calcific CT lesion (SSCCCTL), measuring 20 mm or less were analysed. The mean age was 20 years and 60% were in the first and second decades. Eighteen (18.5%) patients had a previous history of unprovoked seizures, with complex partial seizures (61%) being the most common type. Seizures could be localized to a single ILAE site in 73% of patients. None had neurological deficit and electroencephalograph abnormalities were noted in 29% of patients. Fifty-one (53%) patients had breakthrough seizures and were more common with frontal location. By 7 years 71.5% (95% confidence intervals (CI) 53.7-85.4) of patients achieved 3-year remission and 66% (CI 32.4-88.2) had achieved 5-year remission. The clinical pattern of the seizures was clearly distinctive to allow it to be localized to the location of the lesion on computerized tomography (CT) scan in 25 (26%) patients and in another 31 (31%) patients nearer to the anatomical site of the lesion on the CT scan. There was discordance between clinical localization and CT location of the lesion in 15 patients. Nine of the 10 patients with occipital or parieto-occipital location had focal tonic-clonic seizures with secondary generalization. Both patients with temporal location had motor seizures. The relevance of these findings to the seizure propagation was discussed.

Taenia solium cysticercosis in young pigs: age at first infection and histological characteristics

In spite of the vast knowledge that exists in the fields of immunology, biochemistry, diagnosis and treatment, the basic facts about the dynamics of the transmission of Taenia solium are incomplete. The present study determines the age at which piglets become infected in a rural community of Mexico, where the climate is divided into the dry and rainy seasons. It was found that piglets become infected during the dry months, not so during the rainy season. They pick up eggs at the age of 2 to 4 weeks and the metacestodes are present in the liver. In older animals aged 4 to 6 months, the larvae were also found in the muscles. In a 6-month-old pig larvae were found in the muscles and brain. These findings may be explained by behavioural studies of free living pigs and climatic conditions.

Neurocysticercosos in South-Central America and the Indian subcontinent. A comparative evaluation

Neurocysticercosis is an important public health problem in South-Central American and South Asia. A review of the differences in epidemiological and clinical attributes of cysticercosis and taeniasis in South Central America and India, respectively, is undertaken in the present communication. Intestinal taeniasis is hyperendemic in several American countries. In comparison, the prevalence of Taenia solium infestation is lower in India. The clinical manifestations in several American neurocysticercosis series comprise epilepsy, intracranial hypertension and meningeal-racemose cysticercosis, in roughly equal proportions. An overwhelming majority of the Indian subjects present with seizures. The commonest pathological substrate of the disorder in Indian patients is the solitary parenchymal degenerating cyst. The reasons for the predominance of solitary forms in India, and of multilesional forms in South Central America are discussed. The magnitude of Taenia solium infestation and the frequency of pork consumption in a given population appear to influence the quantum of cyst load in affected individuals.

[Evoked potentials in neurocysticercosis]

In 25 patients with cysticercosis of central nervous system, classified in two clinical forms, benign and malign, evoked potentials were obtained. Normal exam was found in 9 cases with the benign form. From 4 patients with malign clinical presentations, 2 had multiple abnormalities of the evoked potentials, and F wave alterations (mixed pattern). The authors suggest that this mixed pattern may be indicative of severe prognosis.

Albendazole therapy for neurocysticercosis: a prospective double-blind trial comparing 7 versus 14 days of treatment. Cysticercosis Working Group in Peru

OBJECTIVE

To compare the effectiveness of two regimens of albendazole therapy for neurocysticercosis.

DESIGN

Randomized, double-blind clinical trial.

SETTINGS

Patients admitted to neurologic wards in Lima, Peru.

PATIENTS

Adult patients with active neurocysticercosis demonstrated by CT and Western blot (immunoblot).

INTERVENTION

One week (n = 25) versus 2 weeks (n = 25) of albendazole therapy.

MEASUREMENTS

Decrease in the number of cysts on CT.

RESULTS

Effectiveness of albendazole was 78%, with no difference between the groups when compared 3 months after therapy. Complete cure was obtained in only 38% of patients. Patients with more than 20 cysts had poorer responses to therapy. The clinical course and EEG evolution improved in most patients. Side effects were present in 38% of patients, mainly mild, transient gastrointestinal symptoms. Therapy was also associated with exacerbation of neurologic symptoms. Two patients died in the first year after therapy, both because of aggregated infections of ventricle-peritoneal shunts. One-year follow-up CT showed lesions in three of 10 patients presumed to be cured 3 months after therapy.

CONCLUSIONS

Extension of albendazole therapy for more than 7 days adds no benefits for the patients.

Evolution of cerebral edema and its relationship with power in the theta band

In previous papers we have proposed that in patients with space-occupying lesions, delta power was related with the volume of the lesion and theta power with the volume of the edema. In this report we analyze the evolution of 10 patients with space-occupying lesions in whom we measured the volume of the lesion and of the edema before and after treatment that produced changes in these volumes. EEGs were recorded in the leads of the 10-20 system referenced to linked earlobes. Delta and theta powers were calculated for voltage and current source densities (CSD) and compared with age-norms to compute conventional Z-maps. These maps provide probability statements about the deviation of observed values from the norm. Rank correlations between the change in the volume of the lesion before and after treatment and the change in Z-values before and after treatment were significant only in the delta band. However, rank correlations between the change in the volume of the edema and the change in EEG Z-values were only significant in the theta band. These correlations were higher for CSD than for voltage estimates. We also observed that the site of the lesion and of the edema was better represented by CSD maps than by voltage maps. These results are also in agreement with our previous reports, in which we observed more precise localization of brain lesions by CSD than by voltage estimates.

Large cerebral infarction during praziquantel therapy in neurocysticercosis

BACKGROUND

Large cerebral infarction is a rare complication of neurocysticercosis. Endarteritis by inflammation of the leptomeninges is known to be its cause.

CASE DESCRIPTION

A 59-year-old man with known neurocysticercosis developed a large cerebral infarction during praziquantel therapy. A follow-up MRI obtained immediately after his cerebral infarction demonstrated notable decrease in the size of the cysts and more prominent enhancement around the peripheral margins of the cysts and the major vessels in comparison with the initial MRI. Cerebral angiography disclosed occlusions and narrowing of both internal carotid arteries at the supraclinoid portions, where multiple cysts were found on the MRI.

CONCLUSIONS

Findings in our patient strongly suggest that a secondary inflammation reaction caused by the destruction of the cysts might have enhanced the process of endarteritis. The possible deleterious effects of praziquantel therapy should be considered in the treatment of patients with subarachnoid cysticerci.

Inhibition of sexual behavior in male mice infected with Taenia crassiceps cysticerci

Prominent estrogenization and deandrogenization ensue in male mice as a consequence of experimental intraperitoneal infection with Taenia crassiceps cysticerci. The impact of these endocrine changes upon sexual behavior was explored in a group of infected Balb/c male mice at weekly intervals for 15 wk and compared with the behavior of otherwise paired, nonparasitized male mice. Mounting, intromission, and ejaculation responses markedly declined as infection progressed. Six weeks after infection, none of the infected mice displayed ejaculation, the number of mounts and intromissions gradually decreased, and their latencies increased, until, by the 13th wk, none of the parasitized mice showed any sexual response toward female mice. Fifteen weeks after infection, the number of metacestodes per host increased to a couple of thousand, the mean serum estradiol level was approximately 50 times higher than the normal value, and testosterone fell to 5% of its normal level. To fully assess that the inhibition of sexual behavior resulted from the decrease in testosterone levels, a group of 8-wk-infected mice received testosterone, and complete restoration of their sexual behavior was observed. Inhibition of masculine sexual behavior during the infection period is the result of hormonal changes, estradiol being ineffective in maintaining copulation.

Intravitreal cysticercosis

Examination of a 36-year-old man with naked visual acuity of 20/20 revealed a floating, conspicuous cyst of Cysticercus cellulosae in the vitreous cavity of the right eye. A vitreous traction band from the vitreous base and the optic disc was connected to the lodging bulb of the cyst. In the superonasal area, an ovoid retinal break surrounded by a white retinal lesion with two elliptical retinal hemorrhages was found, and this seems to be the previous lodging site of the cyst. A pars plana vitrectomy was performed to remove the parasite, and laser photocoagulation was carried out around the retinal break. Four months after the operation, the patient was satisfied with naked visual acuity of 25/20 without any complication in the affected eye.

Magnetoencephalographic features in neurocysticercosis

BACKGROUND

Magnetoencephalography (MEG) is a method of determining the brain activity noninvasively be detecting the magnetic fields associated with neuronal electrical activities.

METHODS

By using 37-channel DC-superconducting quantum interference devices, MEG activity was recorded in a patient with neurocysticerosis, who had a long-term history of epilepsy.

RESULTS

MEG clearly demonstrated accumulation of current dipoles originating from high-frequency waves around the cysticercal cyst, while scalp electroencephalogram failed to reveal paroxysmal discharge. Intraoperative electrocorticography revealed multiple spike activities around the lesion, consistent with MEG findings.

CONCLUSIONS

We discussed the application of MEG to the patients with neurocysticercosis in estimating epileptogenic sources.

Retrobulbar optic nerve cysticercosis. Case report

The authors report a first case of intraoptic neurocysticercosis in a 12-year-old boy living on Reunion Island. Cysticercosis of the retrobulbar portion of the optic nerve is rare. Because of the patient's age and disturbances in both visual acuity and visual field, it was initially believed to be an optic nerve tumor. Computerized tomography scans and surgical aspects were confirmed by pathological findings. A conservative removal using en bloc orbitotomy showed good functional and aesthetic results.

Comparison of single and trickle infections of pigs with eggs of the Asian Taenia

Two groups of seven Belgian Landrace piglets each were either infected with a single dose of 3000 or with five consecutive doses of 600 Asian Taenia eggs at weekly intervals. Nine weeks after the first infection all pigs were autopsied and the number of metacestodes was obtained by slicing the liver. There were no significant differences between the mean number of viable or dead cysts present in both groups of animals. Only very low numbers of living metacestodes were found: 0.4% (3/779) of the total number of cysts present in the single infection group and 1.8% (13/707) in the trickle infection group. Circulating antigens could be detected in only four out of 13 animals and no differences in antibody kinetics were present between the two groups of pigs. The presence of high numbers of degenerated cysts in experimental as well as in field conditions seems to indicate that the biotic potential of the Asian Taenia is rather low.

Experimental Taenia solium cysticercosis in pigs: characteristics of the infection and antibody response

Pigs were infected with taeniid eggs to study the susceptibility to infection and reinfection of the animals of mixed breeds and of different ages, the viability and death of the metacestodes in the host tissue, and the antibody response which accompanies these events. Sixteen pigs were infected with Taenia solium eggs for this purpose. At necropsy metacestodes were counted in 2 kg of shoulder muscles and classified as vesicular or caseous, and all the metacestodes in brains were counted and classified. The results show that pigs inoculated at 49 and 60 days of age became infected to different degrees and reacted differently to the presence of parasites. In the brain the metacestodes remain viable for longer periods than in muscles. Enzyme-linked immunosorbent assay (ELISA) showed a significant rise in antibodies after infection, which started to decrease 92 days post-infection (p.i.). Pigs with viable cysts remained seropositive up to the end of the experiment (281 days p.i.). Antibody levels rose further after reinfection or after treatment. The results of Western blot were comparable to those of ELISA. Antigens of 13, 14 and 18 kDa were most frequently recognized in early infections and then started to decrease 92 days p.i., while the antigens of 42, 50 and 24 kDa were recognized during later stages of infection (200 days p.i.). The results suggest that older animals are more resistant to the infection [corrected].

Spectrum of epilepsy in neurocysticercosis: a long-term follow-up of 143 patients

To characterize the clinical profile and the prognostic factors of the epilepsy due to parenchymal neurocysticercosis (NCC) 143 patients were analysed. Patients (62 men, 81 women) had a mean age at epilepsy onset of 29 years (range 2-71), mean epilepsy duration of 16 years (range 1-58) and mean follow-up of 5.2 years. Seizures were generalised tonic-clonic (GTC) in 50 patients (35%), simple partial (SP) in 66 (46%) and complex partial (CP) in 27 (19%). Epilepsy began as a single seizure in 73% and as a cluster of seizures or status epilepticus in 27%. Seizures were controlled in 64% of patients. Multivariate analysis revealed that significant prognostic factors associated with seizure control were type of seizures and age at epilepsy onset. Control is more likely in GTC and SP seizures and in patients with a higher age at seizures onset. Our analysis establishes that epilepsy due to NCC is a heterogeneous syndrome concerning age and mode of onset, seizure type, duration of epilepsy and pattern of evolution probably related with different pathogenic mechanisms.

Single parenchymal brain cysticercus in the acute encephalitic phase: definition of a distinct form of neurocysticercosis with a benign prognosis

Fifty four patients with a single parenchymal brain cysticercus in the acute encephalitic phase were studied to outline the features of this form of the disease. Seizures were the presenting symptom in all cases. Twenty six patients had a single seizure and 28 had several seizures before admission. Neurological examination was normal in 45 patients and showed focal signs in nine. All patients had a single enhancing CT lesion; all but three lesions were < 20 mm. Anticonvulsants were started in every patient. Forty five patients were followed up for 18 (SD 6) months. Thirty seven of these 45 patients received albendazole. Four weeks after the trial, CT showed resolution of lesions in all cases. The remaining eight patients refused albendazole, and CT showed persistence of lesions by 16 weeks in six cases. At the end of the follow up, all patients who received albendazole were free of seizures as opposed to three of eight patients who did not receive the drug. Focal signs improved in the nine patients with these signs (all received albendazole). Recognition of this form of neurocysticercosis permits early treatment with albendazole that greatly improves the prognosis.

Experimental infection of an isolate of Taenia solium from Hainan in domestic animals

The present study was designed to determine the susceptibility of domestic animals to an isolate of Taenia solium from Hainan Province, People's Republic of China. A total of 162 cysticerci were recovered from two pigs and 21 from two dogs after experimental inoculation. Cats, goats and a calf were not susceptible to T. solium. Cysticerci were recovered mainly from muscles of the pigs and all were alive. The remainder were in the liver and only one was alive. In the dog, all cysticerci were recovered from the muscles and all were alive.

Radiologic evaluation of the liver and gastrointestinal tract in rats infected with Taenia taeniaeformis

In rats infected with the cestode Taenia taeniaeformis, hepatomegaly results from development of parasitic cysts in the liver. Diffuse nodular mucosal hyperplasia in the glandular region (corpus and antrum) of the stomach, and gross thickening of the intestinal mucosa also result. Between postinfection days (PID) 21 and 84, radiologic observations were made after oral administration of a barium sulfate suspension in T taeniaeformis-infected rats and in age/sex-matched controls. There was radiographic evidence of hepatic enlargement at PID 21. Enlargement of the gastric folds was first observed along the greater curvature of the stomach at PID 35. Fimbriation of small intestinal mucosal surfaces resulted from thickening of the intestinal villi and was observed in the duodenum at PID 21. Intestinal motility was assessed, and contractions were counted, using image intensification fluoroscopy, then were recorded on videotape. There were no significant differences between control and infected rats for gastric emptying time, intestinal transit time, and number of intestinal contractions per minute. Barium contrast radiography clearly indicated large gastric folds, thickening of the small intestinal villi, and hepatic enlargement, and was useful for assessing gastrointestinal motility.

Neurocysticercosis

Neurocysticercosis can be a cause of new-onset seizures. Cysticercosis is caused by fecal-oral spread of the parasite Taenia solium, the pork tapeworm, from affected individuals. Neurocysticercosis results from parasitic invasion of the central nervous system. The clinical presentation ranges from headaches to acute obstructive hydrocephalus. Computed tomography or magnetic resonance imaging is usually diagnostic, while serologic tests are generally less reliable. Treatment consists of praziquantel or albendazole, generally prescribed in combination with oral corticosteroids.

Isolated fourth ventricle in neurocysticercosis: pathophysiology, diagnosis, and treatment

Four cases of isolated fourth ventricle in neurocysticerocosis are reported (three after ventriculoperitoneal shunting, and one after hydrocephalus without shunting). Diagnosis was made based on computed tomography (CT) and/or CT cisternogram/ventriculogram. Three patients underwent fourth ventricle drainage (two died and the third remains well). The fourth patient refused surgical treatment and continues to have severe ataxia. Diagnosis, pathophysiology, and treatment of this entity in neurocysticercosis are discussed.

Spontaneous extrusion of cysticercosis: report of three cases

We report three cases of spontaneous extrusion of cysticercosis. In two cases, it got extruded from the orbit and in one case from the subconjunctival space. Extrusion of cysticercosis was associated with improvement in clinical signs and symptoms.

Epilepsy due to neurocysticercosis: analysis of 203 patients

We reviewed clinical, EEG, and CT findings of 203 patients with epilepsy due to neurocysticercosis. Seizures were generalized in 121 patients and partial in 82. Thirty-two patients had focal signs and eight had papilledema. Eighty-one had generalized and 16 had focal EEG abnormalities. CT showed parenchymal brain calcifications in 53 patients and cysts in 150. There was an increased rate of focal signs in patients with single cysts as compared with patients with multiple cysts, and focal EEG abnormalities were present only in patients with single cysts. Fifty patients were lost to follow-up. The remaining 153 patients were followed for 28 +/- 6 months; of these, 31 had calcifications and 122 had cysts. Anticonvulsants were started after the first visit in every patient. The 31 patients with calcifications remained free of seizures. Ninety-five of the 122 patients with cysts were also treated with anticysticercal drugs; of these, 79 (83%) had control of seizures. In contrast, only seven (26%) of 27 patients who did not receive anticysticercal drugs had control of seizures, indicating a strong correlation between the use of anticysticercal drugs and seizure control. Finally, of the 21 patients in whom anticonvulsants were withdrawn, 16 had relapses.