Neurocysticercosis: regional status, epidemiology, impact and control measures in the Americas

Aggregation of Taenia solium cysticerci in pigs: Implications for transmission and control

Parasite aggregation within hosts is a fundamental feature of parasite distributions, whereby the majority of parasites are harboured by a minority of hosts. Parasite aggregation can influence their transmission and hence control. In this narrative review, possible sources of aggregation of Taenia solium cysticerci in pigs are discussed, along with implications for control of the parasite. While heavy T. solium infections in pigs could most likely be associated with ingestion of high doses of infective parasite eggs, consistent with coprophagic behaviour of pigs, lighter infections indicate a role of indirect routes of transmission to pigs, mostly from lower infection doses. Light infections are likely to be missed by commonly used diagnostic methods - tongue examination or meat inspection - and end up in the food chain. Hence, they entail a 'hidden' risk and are of a particular public health concern, especially in areas where meat is consumed raw or undercooked. To be effective and sustainable, control strategies against T. solium likely require a broader understanding of, and consideration for parasite transmission dynamics. More importantly, a holistic One Health approach incorporating interventions on humans, pigs and the environment will likely have a larger, more successful and sustainable impact.

Neurocysticercosis: A Review into Treatment Options, Indications, and Their Efficacy

Neurocysticercosis, due to the localization of Taenia solium larvae in the Central Nervous System, is a neglected tropical disease still endemic in much of Latin America, Asia and sub-Saharan Africa. The therapeutic management of NC has gradually improved with the establishment of neuroimaging studies (CT and MRI) in endemic countries and with the demonstration of the efficacy of albendazole and praziquantel in the 1980s. But the morbidity and mortality of this preventable disease remain an unacceptable fact. In this scoping review, we will revise the different treatment options and their indications.

The role of cooking practices in the transmission of the foodborne parasite Taenia solium: A qualitative study in an endemic area of Southern Tanzania

The pork tapeworm Taenia solium is a zoonotic food-borne parasite endemic in many developing countries causing human cysticercosis and taeniosis as well as porcine cysticercosis. It mainly affects the health of rural smallholder pig farmers and their communities, resulting in lower health status, reduced pork quality, and economic loss due to condemnation of pigs or low pricing of pork. This qualitative study aimed to identify key food related practices linked to consumption of pork at village level, of importance for transmission of taeniosis. We used an interpretivist-constructivist paradigm in a multiple case study of exploratory qualitative research design. Data was acquired through guided and probing interviews with 64 pork cooks, and 14 direct observations in four villages in a T. solium endemic area of Mbeya Region in the Southern Highlands of Tanzania. The study showed that the informants were members of communities of practice through their pork cooking practices, one community of practice for the restaurant cooks and one for the home cooks, learning, sharing, and distributing their cooking skills. Furthermore, the analysis showed that the pork cooks generally had some awareness of there being something undesirable in raw pork, but they had very diverse understandings of what it was, or of its potential harm. Major potential transmission points were identified in restaurants and in home kitchens. It appears that the pork cooks act according to socio-cultural and economic factors guiding them in their actions, including pressure from customers in restaurants, the family values of tradition in the home kitchens, and the culturally guided risk perception and appraisal. These practices might generate potential transmission points. Future research on interventions aimed at preventing the spread of T. solium taeniosis should recognise the importance of tradition and culture in risky food practices.

Child Neurology Care in Latin America: Challenges and Potential Solutions

BACKGROUND

The current practice of child neurology in Latin America has been impacted by the waves of sociopolitical unrest that in the last decades have swept the region.

METHODS

We searched the available literature referring to the situation of child neurology in Latin America and conditions that specifically impact the region.

RESULTS

In lower-middle-income countries, the number of child neurologists is inadequate. Child neurologists working in large public hospitals can only afford to do so on a part-time basis as these institutions are chronically underfunded. Several circumstances are particularly relevant to Latin America: Spanish is the main language spoken, something that limits the opportunity to keep local child neurologists up to date. The structure of health care systems in Latin America varies significantly. Some countries have fragmented systems with inadequate capacity to offer equitable access to medical care. Latin America has been impacted by epidemics of arthropod-borne viruses: zika, chikungunya, and dengue. It stands to reason that the COVID-19 pandemic will affect the distribution of resources for chronic neurological conditions.

CONCLUSIONS

The virtual platforms such as Zoom, expanded during the COVID-19 pandemic, are useful not only to improve access to care through telemedicine but also for educational purposes. Collaborative efforts to support educational courses and symposia in Spanish are ongoing. It is necessary to set short- and long-term priorities to improve child neurology care in the region. Immediate priorities should focus on improving the diagnosis of neurological conditions, making emphasis on locally available resources.

An exploratory assessment of human and animal health concerns of smallholder farmers in rural communities of Chimborazo, Ecuador

Background

Livestock play important economic and cultural roles in smallholder communities of Ecuador, yet they also serve as potential sources of zoonotic infections. Understanding the animal and human health concerns of smallholder farmers is important in guiding strategies for improvement of the health and livelihoods of these resource-poor farmers. Therefore, the objectives of this study were to: (a) assess the health concerns of smallholder farmers; (b) explore animal and waste management practices; and (c) identify predictors of pediatric and livestock diarrhea on smallholder farms in Ecuador.

Methods

This is a cross-sectional survey of 58 smallholder farmers in three communities of Chimborazo province, Ecuador. Data were collected on household demographics, smallholding characteristics, type of animals owned, human-animal interactions, health concerns, and 30-day occurrence of human as well as animal diarrhea. Summary statistics were computed and logistic models used to investigate predictors of pediatric and animal diarrhea.

Results

All respondents reported keeping animals. Animals kept included cattle, pigs, poultry, dogs, guinea pigs, cats, sheep, horses, rabbits, donkeys, or other livestock. More than half of the respondents named diseases as their greatest personal (55.2%) or family (58.6%) health concern, while an even greater percentage (60.3%) reported physiological stress as the primary health concern for their animals. Occurrence of diarrhea in the 30 days prior to the study was reported by 12.1% of the respondents. Additionally, 15.2% and 55.2% of the households reported diarrhea among children and animals, respectively. The majority (65.5%) of the households had toilets, while the remainder had either latrines (27.6%) or no sanitation facilities (6.9%). However, only 9.1% of the smallholdings had either a toilet (3.6%) or a latrine (5.5%) onsite and yet the farmers tended to spend most of the day at the smallholdings. Potential exposures to gastrointestinal pathogens included food- or water-borne sources (93.5% of children; 91.4% of adults) and blood-borne or fecal sources (80.4% of children; 100% of adults). Although 98.3% of the respondents kept cattle, only 27.6% had animal enclosures and even fewer (15.5%) had animal waste management plans. The odds of animal diarrhea were significantly higher (Odds Ratio [OR] = 8.7; 95% Confidence Interval [1.0–75.0]; p = .049) among households that had animal waste management plans compared to those that did not. None of the variables investigated were significant predictors of pediatric diarrhea.

Conclusions

Ongoing surveillance is needed to develop estimates of diarrhea incidence among smallholder families and their livestock. The impact of different animal management strategies on the potential pathogen exposure of smallholders warrants further investigations. Improving sanitation infrastructure and animal waste management strategies is recommended.

Epilepsy diagnosis based on one unprovoked seizure and ≥60% risk. A systematic review of the etiologies

BACKGROUND

According to the International League Against Epilepsy (ILAE) criteria, epilepsy can be diagnosed after one unprovoked (or reflex) seizure when there is a ≥60% of seizure recurrence in the next decade. The application of this diagnostic criterion, however, is challenging because the risk of recurrence based on different etiologies is not easily retrievable from the literature.

OBJECTIVE

To assess etiologies that permit a diagnosis of epilepsy after a single unprovoked seizure.

METHODS

We conducted a systematic review of the literature search using PubMed, Scopus, and Cochrane library from January 1950 to December 2020 with the keywords: recurrence, risk of recurrence, absolute risk, risk ratio, risk, seizures, epilepsy, structural, infectious, metabolic, immune, and genetic. We included articles that reported estimates of risks of a subsequent unprovoked seizure. Etiologies were categorized according to the ILAE epilepsy classification. The quality of the evidence was evaluated with PRISMA. Descriptive statistics were used.

RESULTS

A total of 25,044 articles resulted from searching three databases. After authors removed duplicates, 18,911 articles remained. We screened by title and abstract, 40 articles were reviewed and finally, two articles were included. The mean follow-up was 8 years and the mean for a risk to present a subsequent unprovoked seizure was 66.6% and included structural etiologies as stroke, traumatic brain injury, cavernous malformation, arteriovenous malformation, and neuroinfections (unspecified agents). Study quality characteristics are classified with low strength of evidence and moderate-quality cohort.

CONCLUSIONS

We found that stroke, traumatic brain injury, cavernous or arteriovenous malformations, and unspecified CNS infections can meet the epilepsy diagnosis after one unprovoked seizure based on low strength of evidence and moderate quality of cohorts.

Isolated Intramedullary Lumbar Spine Neurocysticercosis: A Rare Occurrence and Review of Literature

Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system. Spinal cysticercosis is a rather rare clinical occurrence. Intramedullary (IM) spinal NCC is rarer still. Furthermore, cases of IM-NCC at lumbar levels are few and far between. We present a case of a 35-year-old male patient who was diagnosed to have IM-NCC at L2-3 level and was managed surgically with no recurrence at 2 years of follow-up. A systematic literature review (1992-2020) highlights it to be only the third case reported with exclusive lumbar involvement.

Cysticidal effect of a pure naphthoquinone on Taenia crassiceps cysticerci

Cysticercosis is a disease caused by the metacestode of the parasite Taenia solium (T. solium). In humans, the most severe complication of the disease is neurocysticercosis. The drug of choice to treat this disease is albendazole; however, the bioavailability and efficacy of the drug are variable. Therefore, new molecules with therapeutic effects against this and other parasitic infections caused by helminths must be developed. Naphthoquinones are naphthalene-derived compounds that possess antibacterial, antifungal, antitumoral, and antiparasitic properties. The aim of this work was to evaluate the in vitro anti-helminthic effect of 2-[(3-chlorophenylamino)phenylmethyl]-3-hydroxy-1,4-naphthoquinone, isolated from a natural source and then synthesized (naphthoquinone 4a), using an experimental model of murine cysticercosis caused by Taenia crassiceps (T. crassiceps). This compound causes paralysis in the cysticerci membrane from day 3 of the in vitro treatment. Additionally, it induces changes in the shape, size, and appearance of the cysticerci and a decrease in the reproduction rate. In conclusion, naphthoquinone 4a has in vitro cysticidal activity on T. crassiceps cysticerci depending on the duration of the treatment and the concentration of the compound. Therefore, it is a promising drug candidate to be used in T. crassiceps and possibly T. solium infections.

Detection of Porcine Cysticercosis in Meat Juice Samples from Infected Pigs

BACKGROUND

Seroprevalence of porcine cysticercosis has been generally studied using enzyme-linked immunosorbent assays (ELISA) detecting either antigens or antibodies in sera. However, serum is not always readily available. The objective of this study was to assess the diagnostic potential of meat juice in detecting porcine cysticercosis using a cysticercosis antibody ELISA.

METHODS

Sera and meat juice samples from 13 different organs/tissues were collected from nine pigs naturally infected with cysticercosis and from six uninfected pigs reared under hygienic conditions. The sensitivity of the cysticercosis antibody ELISA in detecting porcine cysticercosis in meat juice samples was compared to that in serum samples from the same pigs.

RESULTS

Using sera, cysticercosis was detected in all nine pigs harbouring cysticerci, but not in those reared under hygienic conditions. The sensitivity of the ELISA was highest in meat juice extracted from the diaphragm (100%), heart (89%) and neck muscle (78%) of the nine infected pigs, whereas it varied between 0 and 44% in the other samples.

CONCLUSION

To the best of our knowledge, this is the first study for T. solium cysticercosis serology to use meat juice. Our results show that meat juice from pig carcass organs or muscles is a promising diagnostic specimen for the detection of porcine cysticercosis. More studies including a large sample size of pigs with varying degrees of cysticercosis infection are needed to further prove this concept.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Socio-economic and health costs of porcine/human cysticercosis, neurocysticercosis and epilepsy to small-scale pig producers in Tanzania

BACKGROUND

Porcine cysticercosis, human cysticercosis, neurocysticercosis, and epilepsy pose a serious public health risk and lead to economic losses to the small-scale pig farmers in Tanzania's rural areas. It also resulted in lowering the pig's prices, high treatment expenses, lower labour productivity, and social discrimination. In Tanzania, small-scale pig producers are unaware of the methods that are used to manage and prevent the diseases associated with Taenia solium.

MAIN BODY

The main goal of the reviewed article was to investigate the socio-economic and health costs of porcine/human cysticercosis, neurocysticercosis, and epilepsy on small-scale pig producers in Tanzania. Several search engines yielded 80 peer-reviewed publications, 44 of which were considered to be relevant to the study. Taenia solium cysticercosis has been reported to cause huge financial losses in the management of pigs posing a burden in terms of vaccination and treatment.

CONCLUSION

The information on porcine/human cysticercosis, neurocysticercosis, and epilepsy is still insufficient in Tanzania. Poor habits, negative perceptions, and attitudes are the result of this misinformation. This review suggests that health education should be emphasized as one of the intervention methods for eliminating all forms of cysticercosis and epilepsy in Tanzania to promote and increase awareness about all forms of cysticercosis and epilepsy in rural areas.

Neurocisticercosis extraparenquimatosa: reto terapéutico A propósito de un caso de la glándula parótida

Introduction:Neurocysticercosis is a parasitosis of the central nervous system, caused by the intake of eggs from taenia solium. It has a high prevalence in certain regions of Latin America, the southeast of Asia, and sub-Saharan Africa, where unhealthy situations still prevail. Clinical case: A 55-year-old woman with clinical symptoms of 2 years of evolution, such as recurrent headaches that had increased recently in addition to tonic-clonic seizures. In these conditions she was admitted to the hospital’s emergency department. Neuroimaging studies (tomography and magnetic resonance imaging) showed the presence of subarachnoid vesicular structures compatible with neurocysticercosis. Therefore, a cestocidal treatment was administered but the patient did not return to her follow-up appointments for 4 years. When she finally went to her appointment, she was very symptomatic and required the administration of 8 cycles of treatment to eradicate the parasites. Discussion: The great heterogeneity and the non-specificity of the signs and symptoms difficult making a diagnosis of neurocysticercosis. Therefore, it is important to look for complementary laboratory and imaging evidence to confirm it. The treatment of neurocysticercosis represents a challenge for the physician. Particularly, when the parasite is located outside the brain parenchyma, subarachnoid cisterns and ventricular system. In less than a third of these patients the parasites disappear with a single cycle of cestocidal treatment. Conclusion: Neurocysticercosis is a disease closely related to poverty, but it is preventable. Research focused on treatments for neurocysticercosis is still necessary. Key words:Neurocysticercosis; taenia solium; seizures; magnetic resonance; cestocidal.

Soil contamination by Taenia solium egg DNA in rural villages in Kongwa district, Tanzania

The presence ofTaenia solium DNA from eggs in soils around the households in four Tanzanian villages in Kongwa district were analysed in relation to seasonal fluctuations and infection risk implications. A total of 192 pooled soil samples from five sampling points per household were examined by droplet digital Polymerase Chain Reaction (ddPCR) from 96 pig-keeping households both during the dry and rainy seasons. The pooled samples were first processed by a flotation-double sieving technique, followed by screening for worm DNA employing universal primers targeting the mitochondrial cytochrome c oxidase subunit I (cox1) gene of human taeniid species and some other helminths. All DNA positive samples were later confirmed by a specific ddPCR probe assay targeting the mitochondrial cox1 gene of T. solium. A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas T. solium DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of T. solium DNA in this study spells out a low risk of exposure to T. solium eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening T. solium eggs in soil.

Partial inhibition of the tricarboxylic acid cycle in Taenia crassiceps cysticerci after the in vitro exposure to a benzimidazole derivative (RCB15)

The benzimidazole derivative, 6-chloro-5-(2,3-dichlorophenoxy)-2-(trifluoromethyl)-1H-benzimidazole (RCB15), has a similar mode of action and efficacy as albendazole, a commonly used anthelminthic drugs. The aim of this study was to evaluate its influence on the tricarboxylic acid cycle in Taenia crassiceps cysticerci. The parasites were cultured in supplemented RPMI medium containing albendazole sulfoxide (ABZSO) or RCB15, for 24 h. Then, frozen in liquid nitrogen for organic metabolites extraction. Samples were analyzed by high performance liquid chromatography and organic acids of the tricarboxylic acid cycle were detected. It was possible to observe changes in the concentrations of all acids involved in this metabolic pathway, with the exception of α-ketoglutarate, which was not detected in the control group neither in most of the treated groups. It indicates that the parasite presented a partial inhibition of the tricarboxylic acid cycle. The significant increase in the concentration of citrate, oxaloacetate and succinate in the RCB15 treated groups may indicate an activation of the fumarate reductase pathway, leading to metabolic distress. Therefore RCB15 may be considered an alternative for the treatment of tissue parasitic diseases, since it induced changes in the main metabolic pathway of the parasite.

Occurrence of Bovine Cysticercosis in Two Regions of the State of Tocantins-Brazil and the Importance of Pathogen Identification

Bovine cysticercosis, caused by Taenia saginata metacestodes, is the cause of significant economic losses to the meat production chain by condemnation and downgrading of infected carcasses. It is also a public health issue causing human taeniasis. This study evaluated the occurrence of bovine cysticercosis at the meat inspection procedures in slaughterhouses of south and north regions of the Tocantins State in Brazil. Specimens identified as cysts of T. saginata were collected and analyzed by molecular (PCR) and histopathological techniques. The cysts were collected from March to December of 2010 in slaughterhouses located in the cities of Alvorada (South) and Araguaína (North). The frequency of cystic lesions during the study was 0.033% (53/164,091) with 69.81% of calcified lesions and 30.9% of live cysts at meat inspection. From 14 samples submitted to molecular analysis, 28.57% (4/14) were positive for T. saginata. The histopathological analysis of the non-T. saginata samples showed lesions suggestive of granuloma and hydatid disease. The results indicated that the identification of the etiological agent is difficult by macroscopic inspection, emphasizing the need to associate specific diagnostic methods at meat inspection in abattoirs. In addition, species-specific PCR would be an effective tool for diagnosis, monitoring, and identifying cysticercosis, assisting the conventional tests.

An epidemiological survey of the magnitude and local perceptions of porcine cysticercosis by two methods in Nyaruguru district, Rwanda

This study investigated the magnitude of porcine cysticercosis (PC), its risk factors, economic effects and the perceptions of 80 pig farmers from Nyabimata (n = 38) and Muganza (n = 42) and 20 registered butchers in the Nyaruguru district of Rwanda. January to December 2013 slaughter records from Kamirabagenzi market were also analysed for PC diagnoses based on the tongue test and meat inspection. During this period, the responding farmers' records showed a tongue test-based PC magnitude (3.9%, n = 984) which was lower than the collective tongue test-based PC magnitude of 9.2% (n = 1720) at Kamirabagenzi (p < .05). The overall magnitude of PC based on routine meat inspection diagnosis at Kamirabagenzi was 4%. The overall magnitude of PC for respondents using Free-range production systems (7.9%) was significantly greater than for those in Semi-intensive (2.1%) and Intensive production systems (1.5%) (p < .05). Though most farmers (90%) knew that PC is zoonotic, only 22.5% of the farmers opted for treatment of PC-infected pigs and 52.5% were willing to seek veterinary inspection while the rest (25%) opted to circumvent veterinary inspection (P > .05). Most butchers (70%) indicated they would circumvent veterinary inspection and continue to slaughter PC-positive animals whilst the rest (30%) indicated they would resell PC positive animals to defray costs (P < .05). The low sensitivity and specificity of methods used for PC detection in the study, implies that this may just be the tip of an iceberg and the actual magnitude is most likely to be much higher. In conclusion, PC is endemic in the Nyaruguru district of Rwanda with a high proportion of positive animals. The condition has public health implications and is worsening the economic plight of the impoverished Nyaruguru community.

Pre-hospitalization, hospitalization, and post-hospitalization costs of patients with neurocysticercosis treated at the Instituto Nacional de Neurologia y Neurocirugia (INNN) in Mexico City, Mexico

The objective of this study was to estimate the direct costs associated with the diagnosis and treatment of neurocysticercosis (NCC) during pre-hospitalization, hospitalization, and post-hospitalization periods for 108 NCC patients treated at the Instituto Nacional de Neurologia y Neurocirugia (INNN) in Mexico City, Mexico. Information on clinical manifestations, diagnostic tests, hospitalizations, surgical procedures, prescription medication, and other treatments was collected via medical chart reviews. Uncertain values for costs and frequency of treatments were imputed using bootstrap techniques. The average per-patient pre-hospitalization and hospitalization costs were US$ 257 (95% CI: 185 - 329) and US$ 2,576 (95% CI: 2,244 - 2,908), respectively. Post-hospitalization costs tended to decrease over time, with estimates for the first five years post-hospitalization of US$ 475 (95% CI: 423 - 527), US$ 228 (95% CI: 167 - 288), US$ 157 (95% CI: 111 - 202), US$ 150 (95% CI: 106 - 204), and US$ 91 (95% CI: 27 - 154), respectively. NCC results in a significant economic burden for patients requiring hospitalization, with this burden continuing years post-hospitalization.

Clinical Cysticercosis epidemiology in Spain based on the hospital discharge database: What's new?

BACKGROUND

Cysticercosis (CC) is a tissue infection caused by the larval cysts of the pork tapeworm Taenia solium. It is usually acquired by eating contaminated food or drinking water. CC Cysts can develop in the muscles, the eyes, the brain, and/or the spinal cord. T. solium is found worldwide, but its prevalence has decreased in developed countries due to stricter meat inspection and better hygiene and sanitation. Nevertheless, CC is still a leading cause of seizures and epilepsy. In Spain, The disease is not nationally reportable and data on CC infected animals are also missing, despite the European Directive 2003/99/EC.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a retrospective descriptive study using the Spanish Hospitalization Minimum Data Set (CMBD). Data with ICD-9 CM cysticercosis code ("123.1") placed in first or second diagnostic position from 1997 to 2014 were analyzed. Hospitalization rates were calculated and clinical characteristics were described. Spatial distribution of cases and their temporal behavior were also assessed. A total of 1,912 hospital discharges with clinical cysticercosis were identified. From 1998 to 2008, an increasing trend in the number of CC hospitalizations was observed, decreasing afterwards, in parallel with a decrease in the external migration rate. The Murcia region had the highest median hospitalization rate (13.37 hospitalizations/100,000 population), followed by Navarra and Madrid. The 16-44 age group was the most represented (63.6%). The three most frequent associated diagnoses were epilepsy and convulsions (49.5%), hydrocephalus (11.8%) and encephalitis/myelitis/meningitis (11.6%).

CONCLUSIONS/SIGNIFICANCE

There is a need for a common strategy on data collection, monitoring and reporting, which would facilitate a more accurate picture on the CC epidemiological scenario. Even if most cases might be imported, improving the human and animal CC surveillance will result useful both in gaining extended disease knowledge and reducing morbidity and related-costs.

A benzimidazole derivative (RCB15) in vitro induces the alternative energetic metabolism and glycolysis in Taenia crassiceps cysticerci

The emergence of resistance to albendazole has encouraged the search for effective alternatives for cysticercosis and other parasitosis treatment. RCB15 is a benzimidazole derivative that may be used against such diseases. The aim of this study was to determine the in vitro effect of RCB15 on the alternative energetic pathways of Taenia crassiceps cysticerci. The cysticerci were in vitro exposed to albendazole sulphoxide (ABZSO) or RCB15 at different concentrations during 24h. The cysticerci extract and the culture medium were analyzed through spectrophotometry and high performance liquid chromatography as to detect glucose, urea, creatinine and organic acids of the energetic metabolism. The drugs did not influence the protein catabolism. Fatty acids oxidation was enhanced through significantly higher acetate concentrations in the groups treated with RCB15 and ABZSO. Beta-hydroxybutyrate concentrations were decreased which indicates the use of fatty acids towards acetyl-CoA synthesis. There was a decrease in glucose uptake and pyruvate concentrations. The absence of lactate indicates the use of pyruvate in gluconeogenesis. Therefore it is possible to conclude that RCB15 enhanced the alternative energetic pathways of cysticerci in vitro exposed to different concentration, with emphasis on the fatty acids catabolism.

Epidemiology of neurocysticercosis and epilepsy, is everything described?

In recent years clinical and epidemiological research on cysticercosis has gained significant interest in some countries, especially in Latin American countries and some countries in Asia and Africa. For many years it has been proposed that the higher prevalence of epilepsy seen in some regions such as Latin-America could be explained by parasitic infections, particularly neurocysticercosis (NCC). In this review we discussed selected epidemiological topics of the association of NCC and epilepsy, such as global distribution around the world, identification of NCC in developed countries, drug resistant epilepsy and NCC. Finally this review presents a critical review of biases of the published literature in NCC. This article is part of a Special Issue entitled "Neurocysticercosis and Epilepsy".

Prevalence and risk factors for porcine cysticercosis in rural communities of eastern Minas Gerais, Brazil

ABSTRACT: Cysticercosis is caused by Taenia solium, a parasitic zoonosis that affects human and pigs raised free-range in developing countries. The epidemiology of the taeniosis cysticercosis complex in Brazil is poorly understood especially when it comes to field research. The aim of this study was to estimate the prevalence and identify the risk factors associated with porcine cysticercosis in rural communities located in the east of Minas Gerais (MG), Brazil. From 371 farms in the county of Tumiritinga/MG, 101 farms from 14 communities were randomly sampled. Blood samples from pigs were collected, and epidemiological questionnaires were carried out. The serum samples obtained were analyzed through immunodiagnosis techniques, including ELISA and Western Blot, both for the detection of antibodies. The data obtained by different surveys were analyzed using EpiInfo 3.5.1 software to determine seroprevalence and risk factors associated with cysticercosis. The prevalence of farms with porcine cysticercosis was 9.9% (10/101) and antibody-based seropositive was 5.3% (13/247). The results indicate that cysticercosis occurs in high level in the rural area never studied before. These results suggest the presence of tapeworm carriers contributing to the occurrence and maintenance of this zoonotic life cycle in the county. Regarding risk factors, the most significant determinants for porcine cysticercosis in the field were free-range pig management (OR: 17.4, p: 0.0001), the method of disposal of human faeces in the environmental (OR: 7.6; p 0.012), and the size of the farm. Porcine cysticercosis was diagnosed only in areas represented by Agrarian Reform Settlements. From the results, it is possible to recommend as a means of control and prevention the destination of human faeces in appropriate sanitary landfills and the production of pigs in an enclosed area. Additionally, improving education in the communities sampled will indirectly affect the spreading of this disease. The results draw attention to the largest studies of this zoonotic disease in human settlements from rural areas due to the lack of knowledge about the epidemiology of the taeniosis-cysticercosis complex. The results could serve as the basis to support public policies aimed at creating an effective program to control the taeniosis-cysticercosis complex in the studied area. Awareness of TC among medical doctors, veterinarians, meat animal family producers and the public should be developed through appropriate information and education.

TsPKA-r: a potential immunodiagnostic antigen for the detection of porcine cysticercosis

Cysticercosis, caused by metacestodes of Taenia solium, has a significant soci-economic impact and is of considerable importance in public health. However, there are no specific diagnostic antigens to distinguish between T. solim and Taenia hydatigena. In the present study, cAMP-dependent protein kinase regulatory subunit (TsPKA-r), an excretory/secretary (ES) antigen of T. solium, was used to establish a specific and sensitive diagnostic tool for detection of porcine cysticercosis. The full-length sequence encoding TsPKA-r was amplified by PCR, sequenced and then identified by bioinformatics. The fusion protein with 6×His-tags was expressed in E. coli, purified by Ni Sepharose™ 6 Fast Flow and used to test reactionogenicity by immunoblotting. TsPKA-r based indirect enzyme-linked immunosorbent assays (iELISA) showed good performance in recognition of sera of pigs experimentally infected with T. solium metacestodes, with 93.88% sensitivity and 96.40% specificity. There were no cross-reactions against the sera from pigs experimentally infected with T. hydatigena, Toxoplasma gondii or Trichinella spiralis. These results indicate that the TsPKA-r is a promising immunodiagnostic antigen for detection of porcine cysticercosis.

Lumbar spinal intradural neurocysticercosis: A case report

Neurocysticercosis is a parasitic disease that results from the larvae of Taenia solium. While neurocysticercosis is considered as the most common parasitic infection of the nervous system, spinal neurocysticercosis is rare. The present case study investigated a 59-year-old woman, who was admitted to our hospital with pain in the bilateral lower limbs and urinary complaints in the form of straining of micturition with increasing frequency. Magnetic resonance imaging revealed an intradural extramedullary lesion extending from L1/2 to S1 of the spine. Subsequently, a laminectomy from L1 to S1 was performed 3 days post-presentation. Intraoperatively, a thin-walled cyst with clear fluid was identified, extending from L2 to S1. The exposed, white and mucoid cysticerci was removed completely. Which on pathological examination was identified to be cysticercosis.

Human taeniasis: current insights into prevention and management strategies in endemic countries

Human taeniasis is a zoonotic condition resulting from infection with the adult stages of Taenia saginata ("beef tapeworm"), Taenia solium ("pork tapeworm") or Taenia asiatica ("Asian tapeworm"). Although these parasites have a worldwide distribution, the overwhelming burden is felt by communities in low- and middle-income countries. This is particularly true for T. solium, whereby infection of the central nervous system with the larval stage of the parasite (neurocysticercosis) is a major cause of acquired epilepsy in low-resource settings. With a focus on endemic countries, this review provides an insight into the prevention and management of human taeniasis, concluding with some recent case studies describing their implementation. Discussion of the opportunities and challenges regarding current fecal and serological diagnostic assays for detecting Taenia spp. highlights the importance of accurate and accessible diagnostic options for the field situation. The lack of long-term impact on the parasites' lifecycle from human anthelmintic treatment, coupled with the propensity for adverse reactions, highlights the importance of a "two-pronged" approach that considers the relevant animal hosts, particularly in the case of T. solium. Aside from the therapeutic options, this review reiterates the importance of adequate assessment and consideration of the associated behavioral and policy aspects around sanitation, hygiene and meat inspection that have been shown to support parasite control, and potential elimination, in endemic regions.

Diagnóstico e fatores de risco do complexo teníase-cisticercose bovina no município de Salinas, Minas Gerais

RESUMO: Com o objetivo de diagnosticar a situação do complexo teníase-cisticercose bovina no município de Salinas, Minas Gerais, foram coletadas amostras de sangue de 355 bovinos distribuídos em 18 propriedades rurais, sorteadas aleatoriamente. Em cada propriedade, foi aplicado um questionário socioeconômico para a análise de fatores que favorecem a manutenção do complexo teníase-cisticercose bovina. Foi realizado também um levantamento epidemiológico dos casos de teníase diagnosticados nos laboratórios credenciados pela Secretaria Municipal de Saúde de Salinas, no período de 2007 a 2010. A prevalência de cisticercose bovina foi de 4,70% enquanto as prevalências de teníase, encontradas durante os quatro períodos avaliados, foram de 0,29%, 0,36%, 0,24% e 0,24%. Entre os fatores de risco para a manutenção do complexo teníase-cisticercose analisados, foi observada uma relação estatisticamente significativa entre a ocorrência de cisticercose bovina e a ingestão de carne malpassada pelos entrevistados. Foi concluído que a cisticercose bovina está presente no município de Salinas, Minas Gerais, sendo o tratamento térmico ineficiente da carne bovina o principal fator de risco para a manutenção do complexo teníase-cisticercose, o que reforça a necessidade da adoção de medidas de controle com contínua vigilância epidemiológica e sanitária.

Reprint of "Neurocysticercosis-related mortality in Brazil, 2000-2011: Epidemiology of a neglected neurologic cause of death"

Neurocysticercosis (NCC) is an important cause of severe neurological disease mainly in low- and middle-income countries, but data on NCC mortality from endemic areas are scarce. Here we analysed the epidemiological patterns of NCC-related mortality in Brazil. We included all deaths recorded in Brazil between 2000 and 2011, in which NCC was mentioned on death certificates, either as underlying or as associated cause of death. NCC was identified in 1829/12,491,280 deaths (0.015%), 1130 (61.8%) as underlying cause, and 699 (38.2%) as associated cause. Overall age-adjusted mortality rate for the period was 0.97 deaths/1,000,000 inhabitants (95% confidence interval [CI]: 0.83-1.12). The highest NCC-related mortality rates were found in males, elderly, white race/colour and residents in endemic states/regions. Age-adjusted mortality rates at national level decreased significantly over time (annual percent change [APC]: -4.7; 95% CI: -6.0 to -3.3), with a decrease in the Southeast, South and Central-West regions, and a non-significant increasing trend in the North and Northeast regions. We identified spatial and spatiotemporal high-risk mortality clusters located mainly in NCC-endemic areas. Conditions related to the nervous system were the most commonly associated causes of death when NCC was mentioned as an underlying cause, and HIV/AIDS was the main underlying cause when NCC was an associated cause. NCC is a neglected and preventable cause of severe neurologic disease and death with high public health impact in Brazil. There is a clear need to strengthen nationwide epidemiological surveillance and control for the taeniasis/cysticercosis complex.

Taenia crassiceps injection into the subarachnoid space of rats simulates radiological and morphological features of racemose neurocysticercosis

PURPOSE

Neurocysticercosis is a major public health concern. Although its eradication appears feasible, the disease remains endemic in developing countries and has emerged again in Europe and in the USA. Basic studies on neurocysticercosis are needed to better understand the pathophysiologic mechanisms and, consequently, to improve treatment perspectives. Much has been published on experimental parenchymal neurocysticercosis, but there are no experimental models of racemose neurocysticercosis.

METHODS

Cysts of Taenia crassiceps were injected into the subarachnoid space of 11 rats. After 4 months, magnetic resonance imaging (MRI) was performed to verify the occurrence of ventricular dilatation and the distribution of cysts in the cerebrospinal fluid compartments. The histologic assessment was done focusing on changes in the ependyma, choroid plexus, and brain parenchyma.

RESULTS

MRI and histologic assessment confirmed the findings similar to those seen in human racemose neurocysticercosis including enlargement of the basal cisterns, hydrocephalus, and inflammatory infiltration through the ependyma and choroid plexus into cerebrospinal fluid spaces.

CONCLUSIONS

We developed a simple model of racemose neurocysticercosis by injecting cysts of T. crassiceps into the subarachnoid space of rats. This model can help understand the pathophysiologic mechanisms of the disease.

Clinical Symptoms, Imaging Features and Cyst Distribution in the Cerebrospinal Fluid Compartments in Patients with Extraparenchymal Neurocysticercosis

Extraparenchymal neurocysticercosis has an aggressive course because cysts in the cerebrospinal fluid compartments induce acute inflammatory reactions. The relationships between symptoms, imaging findings, lesion type and location remain poorly understood. In this retrospective clinical records-based study, we describe the clinical symptoms, magnetic resonance imaging features, and cyst distribution in the CSF compartments of 36 patients with extraparenchymal neurocysticercosis. Patients were recruited between 1995 and 2010 and median follow up was 38 months. During all the follow up time we found that 75% (27/36) of the patients had symptoms related to raised intracranial pressure sometime, 72.2% (26/36) cysticercotic meningitis, 61.1% (22/36) seizures, and 50.0% (18/36) headaches unrelated to intracranial pressure. Regarding lesion types, 77.8% (28/36) of patients presented with grape-like cysts, 22.2% (8/36) giant cysts, and 61.1% (22/36) contrast-enhancing lesions. Hydrocephalus occurred in 72.2% (26/36) of patients during the follow-up period. All patients had cysts in the subarachnoid space and 41.7% (15/36) had at least one cyst in some ventricle. Cysts were predominantly located in the posterior fossa (31 patients) and supratentorial basal cisterns (19 patients). The fourth ventricle was the main compromised ventricle (10 patients). Spinal cysts were more frequent than previously reported (11.1%, 4/36). Our findings are useful for both diagnosis and treatment selection in patients with neurocysticercosis.

Neurocysticercosis is caused by the accidental ingestion of eggs from Taenia solium whose larvae lodge in the central nervous system. In this study we found that cysts within the cerebrospinal fluid leaded to high rates of raised intracranial pressure, meningitis, seizures and headache. Imaging studies such as magnetic resonance are useful for diagnosis, identification of the compromised sites of the central nervous system and, then, for treatment guidance. The pattern of lesions identified through magnetic resonance in our paper helps physicians on searching and analyzing some typical findings of extraparenchymal neurocysticercosis.

Testing pigs of non-technified rearing farms for serum antibodies against Taenia solium in a region of the state of São Paulo, Brazil

Abstract: Taenia solium is a zoonotic tapeworm of great importance in developing countries, due to the occurrence of human taeniasis and cysticercosis. Pigs have an important role in the biological cycle of the parasite as intermediate hosts. The scientific literature has been describing risk factors associated with the occurrence of this disease that must be avoided in countries with poor sanitation, in order to reduce the exposure of swine to the parasite eggs. This research focused on testing pigs of non-technified rearing farms for serum antibodies against Taenia solium in the region of Jaboticabal municipality, in the state of São Paulo, Brazil. The found prevalence was 6.82% (CI 95% 4.18 - 9.45) at animal level and 28.87% (CI 95% 16.74 - 40.40) at herd level. These figures are probably associated with low technification adoption during animal rearing in the studied area, which increased the exposure of the animals to risk factors associated with the occurrence of Taenia solium complex. The results found based on serological evidences of swine cysticercosis in the studied region serves as a warning to public sanitary authorities to improve public health and control T. solium.

Neurocysticercosis-related mortality in Brazil, 2000-2011: Epidemiology of a neglected neurologic cause of death

Neurocysticercosis (NCC) is an important cause of severe neurological disease mainly in low- and middle-income countries, but data on NCC mortality from endemic areas are scarce. Here we analysed the epidemiological patterns of NCC-related mortality in Brazil. We included all deaths recorded in Brazil between 2000 and 2011, in which NCC was mentioned on death certificates, either as underlying or as associated cause of death. NCC was identified in 1829/12,491,280 deaths (0.015%), 1130 (61.8%) as underlying cause, and 699 (38.2%) as associated cause. Overall age-adjusted mortality rate for the period was 0.97 deaths/1,000,000 inhabitants (95% confidence interval [CI]: 0.83-1.12). The highest NCC-related mortality rates were found in males, elderly, white race/colour and residents in endemic states/regions. Age-adjusted mortality rates at national level decreased significantly over time (annual percent change [APC]: -4.7; 95% CI: -6.0 to -3.3), with a decrease in the Southeast, South and Central-West regions, and a non-significant increasing trend in the North and Northeast regions. We identified spatial and spatiotemporal high-risk mortality clusters located mainly in NCC-endemic areas. Conditions related to the nervous system were the most commonly associated causes of death when NCC was mentioned as an underlying cause, and HIV/AIDS was the main underlying cause when NCC was an associated cause. NCC is a neglected and preventable cause of severe neurologic disease and death with high public health impact in Brazil. There is a clear need to strengthen nationwide epidemiological surveillance and control for the taeniasis/cysticercosis complex.

Codon Usage Bias and Determining Forces in Taenia solium Genome

The tapeworm Taenia solium is an important human zoonotic parasite that causes great economic loss and also endangers public health. At present, an effective vaccine that will prevent infection and chemotherapy without any side effect remains to be developed. In this study, codon usage patterns in the T. solium genome were examined through 8,484 protein-coding genes. Neutrality analysis showed that T. solium had a narrow GC distribution, and a significant correlation was observed between GC12 and GC3. Examination of an NC (ENC vs GC3s)-plot showed a few genes on or close to the expected curve, but the majority of points with low-ENC (the effective number of codons) values were detected below the expected curve, suggesting that mutational bias plays a major role in shaping codon usage. The Parity Rule 2 plot (PR2) analysis showed that GC and AT were not used proportionally. We also identified 26 optimal codons in the T. solium genome, all of which ended with either a G or C residue. These optimal codons in the T. solium genome are likely consistent with tRNAs that are highly expressed in the cell, suggesting that mutational and translational selection forces are probably driving factors of codon usage bias in the T. solium genome.

Cellular immune response in intraventricular experimental neurocysticercosis

Neurocysticercosis (NCC) is considered a neglected parasitic infection of the human central nervous system. Its pathogenesis is due to the host immune response, stage of evolution and location of the parasite. The aim of this study was to evaluate thein situand systemic immune response through cytokines dosage (IL-4, IL-10, IL-17 and IFN-γ) as well as the local inflammatory response of the experimental NCC withTaenia crassiceps. Thein situand systemic cellular and inflammatory immune response were evaluated through the cytokines quantification at 7, 30, 60 and 90 days after inoculation and histopathological analysis. All cysticerci were found within the cerebral ventricles. There was a discrete intensity of inflammatory cells of mixed immune profile, polymorphonuclear and mononuclear cells, at the beginning of the infection and predominance of mononuclear cells at the end. The systemic immune response showed a significant increase in all the analysed cytokines and predominance of the Th2 immune profile cytokines at the end of the infection. These results indicate that the location of the cysticerci may lead to ventriculomegaly. The acute phase of the infection showed a mixed Th1/Th17 profile accompanied by high levels of IL-10 while the late phase showed a Th2 immune profile.

The endocrine-immune network during taeniosis by Taenia solium: The role of the pituitary gland

It is well known that sex hormones play an important role during Taenia solium infection; however, to our knowledge no studies exist concerning the immune response following complete or lobe-specific removal of the pituitary gland during T. solium infection. Thus, the aim of this work was to analyze in hamsters, the effects of lack of pituitary hormones on the duodenal immune response, and their impact on T. solium establishment and development. Thus, in order to achieve this goal, we perform anterior pituitary lobectomy (AL, n = 9), neurointermediate pituitary lobectomy (NIL, n = 9) and total hypophysectomy (HYPOX, n = 8), and related to the gut establishment and growth of T. solium, hematoxylin-eosin staining of duodenal tissue and immunofluorescence of duodenal cytokine expression and compared these results to the control intact (n = 8) and control infected group (n = 8). Our results indicate that 15 days post-infection, HYPOX reduces the number and size of intestinally recovered T. solium adults. Using semiquantitative immunofluorescent laser confocal microscopy, we observed that the mean intensity of duodenal IFN-γ and IL-12 Th1 cytokines was mildly expressed in the infected controls, in contrast with the high level of expression of these cytokines in the NIL infected hamsters. Likewise, the duodenum of HYPOX animals showed an increase in the expression of Th2 cytokines IL-5 and IL-6, when compared to control hamsters. Histological analysis of duodenal mucosa from HYPOX hamsters revealed an exacerbated inflammatory infiltrate located along the lamina propria and related to the presence of the parasite. We conclude that lobe-specific pituitary hormones affect differentially the T. solium development and the gut immune response.

Managing neurocysticercosis: challenges and solutions

Taenia solium neurocysticercosis (NCC) is a major cause of neurological morbidity in the world. Variability in the neuropathology and clinical presentation of NCC often make it difficult to diagnose and manage. Diagnosis of NCC can be challenging especially in endemic and resource-limited countries where laboratory and imaging techniques are often lacking. NCC management can also be challenging as current treatment options are limited and involve symptomatic agents, antiparasitic agents, or surgery. Although antiparasitic treatment probably reduces the number of active lesions and long-term seizure frequency, its efficacy is limited and strategies to improve treatment regimens are warranted. Treatment decisions should be individualized in relation to the type of NCC. Initial measures should focus on symptomatic management, with antiparasitic therapy only to be considered later on, when appropriate. Symptomatic treatment remains the cornerstone in NCC management which should not only focuses on epilepsy, but also on other manifestations that cause considerable burden (recurrent headaches, cognitive decline). Accurate patients’ categorization, better antiparasitic regimens, and definition of new clinical outcomes for trials on NCC could improve management quality and prognosis of NCC. Prevention strategies targeting tapeworm carriers and infected pigs are yielding good results in local models. If local elimination of transmission is confirmed and replicated, this will open the door to cysticercosis eradication efforts worldwide.

Cytokine, antibody and proliferative cellular responses elicited by Taenia solium calreticulin upon experimental infection in hamsters

Taenia solium causes two diseases in humans, cysticercosis and taeniosis. Tapeworm carriers are the main risk factor for neurocysticercosis. Limited information is available about the immune response elicited by the adult parasite, particularly the induction of Th2 responses, frequently associated to helminth infections. Calreticulin is a ubiquitous, multifunctional protein involved in cellular calcium homeostasis, which has been suggested to play a role in the regulation of immune responses. In this work, we assessed the effect of recombinant T. solium calreticulin (rTsCRT) on the cytokine, humoral and cellular responses upon experimental infection in Syrian Golden hamsters (Mesocricetus auratus). Animals were infected with T. solium cysticerci and euthanized at different times after infection. Specific serum antibodies, proliferative responses in mesenteric lymph nodes and spleen cells, as well as cytokines messenger RNA (mRNA) were analyzed. The results showed that one third of the infected animals elicited anti-rTsCRT IgG antibodies. Interestingly, mesenteric lymph node (MLN) cells from either infected or non-infected animals did not proliferate upon in vitro stimulation with rTsCRT. Additionally, stimulation with a tapeworm crude extract resulted in increased expression of IL-4 and IL-5 mRNA. Upon stimulation, rTsCRT increased the expression levels of IL-10 in spleen and MLN cells from uninfected and infected hamsters. The results showed that rTsCRT favors a Th2-biased immune response characterized by the induction of IL-10 in mucosal and systemic lymphoid organs. Here we provide the first data on the cytokine, antibody and cellular responses to rTsCRT upon in vitro stimulation during taeniasis.

Isolated intramedullary spinal cord cysticercosis

Neurocysticercosis is a major cause of epilepsy in developing countries. Cysticercal involvement of the spinal cord is rare even in endemic areas and accounts for 0.7 to 5.85% of all cases. We present a 19-year-old man who presented with weakness of both lower limbs and urinary complaints in the form of straining of micturition with increased frequency, in whom preoperative MRI revealed a well-defined cystic lesion in dorso-lumber cord extending from D11 to L1 level, which on pathological examination was found to be intramedullary cysticercosis.

Neglected parasitic infections in the United States: cysticercosis

Cysticercosis is a potentially fatal and preventable neglected parasitic infection caused by the larval form of Taenia solium. Patients with symptomatic disease usually have signs and symptoms of neurocysticercosis, which commonly manifest as seizures or increased intracranial pressure. Although there are many persons living in the United States who emigrated from highly disease-endemic countries and there are foci of autochthonous transmission of the parasite in the United States, little is known about burden and epidemiology of the disease in this country. In addition, despite advances in the diagnosis and management of neurocysticercosis, there remain many unanswered questions. Improving our understanding and management of neurocysticercosis in the United States will require improved surveillance or focused prospective studies in appropriate areas and allocation of resources towards answering some of the key questions discussed in this report.

Incidence of human Taenia solium larval Infections in an Ecuadorian endemic area: implications for disease burden assessment and control

BACKGROUND

Human cysticercosis is a zoonotic disease causing severe health disorders and even death. While prevalence data become available worldwide, incidence rate and cumulative incidence figures are lacking, which limits the understanding of the Taenia solium epidemiology.

METHODOLOGY/PRINCIPAL FINDINGS

A seroepidemiological cohort study was conducted in a south-Ecuadorian community to estimate the incidence rate of infection with and the incidence rate of exposure to T. solium based on antigen and antibody detections, respectively. The incidence rate of infection was 333.6 per 100,000 person-years (95% CI: [8.4-1,858] per 100,000 person-years) contrasting with a higher incidence rate of exposure 13,370 per 100,000 person-years (95% CI: [8,730-19,591] per 100,000 person-years). The proportion of infected individuals remained low and stable during the whole study year while more than 25% of the population showed at least one antibody seroconversion/seroreversion during the same time period.

CONCLUSIONS/SIGNIFICANCE

Understanding the transmission of T. solium is essential to develop ad hoc cost-effective prevention and control programs. The estimates generated here may now be incorporated in epidemiological models to simulate the temporal transmission of the parasite and the effects of control interventions on its life cycle. These estimates are also of high importance to assess the disease burden since incidence data are needed to make regional and global projections of morbidity and mortality related to cysticercosis.

Evolution, molecular epidemiology and perspectives on the research of taeniid parasites with special emphasis on Taenia solium

Human cysticercosis is known since old historical times in Greece and China; however, human infections by tapeworms have accompanied human beings for more that hundred thousand years. The disease is tightly bound to poverty and lack of hygiene, and has been eradicated in developed countries, but continues being a public health problem in developing countries of Latin-American, Sub-Saharan Africa and Asia, and is also remerging in a number of non endemic countries. It is considered a neglected disease. Here we revise a number of key scientific contributions on taeniid biology that open new avenues for more effective approaches to the control of cysticercosis. The evolution of flatworms and class Cestoda is analyzed, with special emphasis on the emergence of taeniid parasites and the colonization of the human species by tapeworms. The complex molecular host-parasite interplay in this relationship as result of co-evolution between two distantly related organisms. The relevant host and parasite's factors, in the prospect of identifying species-specific molecular markers useful in epidemiological studies carried out in endemic countries. The new possibilities arising with the characterization of the genomes for several species of tapeworms, including a deeper understanding of these organisms, as well as improved tools for diagnosis, vaccination and drug treatment. The need to revise the current control and management strategies for this tropical neglected disease.

Slum Livestock Agriculture

Slums are unplanned squatter human settlements in peri-urban and urban areas where more than 800 million people live. These densely populated areas lack basic public services. Livestock raised in these conditions compete with humans for space and water, and pose a risk to human and animal health. Notwithstanding the risk of disease transmission, slum livestock agriculture plays an essential role in the livelihoods of people and deserves consideration in urban planning and policy making.

Neurocysticercosis in Europe: Still a public health concern not only for imported cases

Neurocysticercosis (NCC), a parasitic disease caused by the larvae of the cestode Taenia solium, is the most frequent parasitic disease of the central nervous system (CNS) in the world and the leading cause of secondary epilepsy in Central and South America, East and South Asia, and sub-Saharan Africa. It is endemic in many low- and middle-income countries of the world. Due to increased travels and immigration, NCC may be diagnosed also in non-endemic areas. In fact, tapeworm carriers from endemic zones can transmit infection to other citizens or arrive already suffering NCC. This phenomenon, occurred first in USA during the last 30 years, has been also observed in Europe, as well as in Australia, Canada, Israel, Japan and Muslim countries of the Arab World. Actually, concerning Europe, although, in some areas only few cases have been described, nevertheless the prevalence of NCC may be considered increasing, especially in Spain and Portugal. We reviewed the literature on the burden of NCC in Europe, by a search of PubMed regarding papers from 1970 to present. We only considered on PubMed published and available papers in English, French, Italian, and Spanish, the languages understood by the authors. One hundred seventy six cases of NCC have been reported in seventeen European countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Netherlands, Sweden, United Kingdom, and Croatia, Norway, Switzerland). A particular epidemic situation is present in Spain and Portugal. In fact, we collected data that show, in Spain, an increasing incidence both in immigrated patients and in those which were born in certain Spanish geographical areas and, in Portugal, prevalence similar to that observed in endemic areas. Globally, it is clear that as a result of increased migrations and travels from endemic regions, NCC is becoming an emerging public health problem in high-income countries, particularly affecting communities where hygiene conditions are poor and sub-sequentially the parasite can spread from human to human through eggs even in absence of a travel to the tropics. NCC is a preventable disease, it derives that it's important to acquire a great consciousness of the epidemiology and to implement accurate surveillance systems.

Characterization of the carbohydrate components of Taenia solium oncosphere proteins and their role in the antigenicity

This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that posttranslational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells.

A new parasiticidal compound in T. solium cysticercosis

The effect of 16α-bromoepiandrosterone (EpiBr), a dehydroepiandrosterone (DHEA) analogue, was tested on the cysticerci of Taenia solium, both in vitro and in vivo. In vitro treatment of T. solium cultures with EpiBr reduced scolex evagination, growth, motility, and viability in dose- and time-dependent fashions. Administration of EpiBr prior to infection with T. solium cysticerci in hamsters reduced the number and size of developed taenias in the intestine, compared with controls. These effects were associated to an increase in splenocyte proliferation in infected hamsters. These results leave open the possibility of assessing the potential of this hormonal analogue as a possible antiparasite drug, particularly in cysticercosis and taeniosis.

State of the art of Taenia solium as compared to Taenia asiatica

Three species of tapeworms infect humans in their adult stage (Taenia solium, Taenia saginata and Taenia asiatica). The 3 are flat, opaque white or yellowish, and exceptional long segmented parasites, measuring 1 to 12 m in their adult stage. In this review, the development of the knowledge regarding the first species, mainly focused on understanding how the larval stage or cysticercus is transmitted to humans, is described. The second species is a cosmopolitan parasite that only causes taeniosis and not cysticercosis; therefore, it will not be included. Information on the third species, which is presently being produced, since this species was recognized as such only at the end of the 20th century, will be discussed at the end of this review.