Parasitoses of the human central nervous system

Toxocarosis in a patient with autism spectrum disorder presenting with severe hypereosinophilia and acute respiratory distress: a case report

A boy with known autism spectrum disorder was transferred to our department due to a rapidly worsening respiratory situation. The patient's history revealed previous treatment with albendazole against a Toxocara infection 2 weeks prior in Poland. Blood analysis showed such severe eosinophilia and markedly elevated levels of IgE that, initially, a hematologic malignancy was suspected. However, diagnostic workup including autoimmune diagnostic, molecular genetic testing, fluorescence in situ hybridization (FISH), bone marrow aspiration, and parasitological testing led to the diagnosis of an insufficiently treated Toxocara infection. Treatment with albendazole and prednisone (six cycles for 4 weeks each) was administered. This treatment regime led to prompt improvement of symptoms and normalization of laboratory findings.

Schistosomiasis Involving the Central Nervous System: Case Report of a Rare Complication

Introduction

Schistosomiasis is a parasitic infection caused by schistosome invasion of blood circulation. Neuroschistosomiasis is a severe cerebral complication that accounts for less than 2.3% of reported cases. Patients present with progressive encephalitis, seizures, or both. Management includes antiparasitic medications, steroids, and surgical intervention. Case Presentation. We report a case of a 44-year-old female who presented to the ER with a history of transient loss of consciousness (LOC) and seizure. Radiological investigations revealed a right frontal brain lesion. Histopathological results confirmed the diagnosis of schistosomiasis.

Conclusion

Schistosomiasis is a parasitic infection commonly diagnosed in patients who live in tropical areas. Early diagnosis with radiological and histopathological evaluation is required to identify patients at risk of developing severe neurological complications.

Trypanosoma cruzi Central Nervous System Infection-Pathogenesis, Clinical Manifestations, Diagnosis, and Treatment

Purpose of Review

Chagas disease (CD) is a neglected tropical disease from the American continent that commonly causes cardiovascular disease. Some patients develop neurological manifestations. We discuss and summarize the pathogenesis, clinical characteristics, diagnosis, and treatment of the central nervous system manifestations of CD.

Recent Findings

Cerebrospinal fluid quantitative polymerase chain reaction tests and next-generation sequencing in tissue samples have facilitated disease diagnosis and follow-up. Novel presentations, including retinitis, are now reported. A new MRI sign called "Bunch of açai berries appearance"-multiple hypointense nodular lesions-has been described recently. Treatment with benznidazole at higher doses and the role of therapeutic drug monitoring need to be further studied in this setting.

Summary

A high suspicion index is paramount to diagnosing Chagas' central nervous system involvement. Standardized molecular diagnostics can aid in the initial workup. Future development of new therapeutic drugs is crucial because of the toxicity profile of the currently available medications.

Emerging and Re-Emerging Parasitic Infections of the Central Nervous System (CNS) in Europe

In a rapidly evolving global landscape characterized by increased international travel, migration, and ecological shifts, this study sheds light on the emergence of protozoal and helminthic infections targeting the central nervous system (CNS) within Europe. Despite being traditionally associated with tropical regions, these infections are progressively becoming more prevalent in non-endemic areas. By scrutinizing the inherent risks, potential outcomes, and attendant challenges, this study underscores the intricate interplay between diagnostic limitations, susceptibility of specific population subsets, and the profound influence of climate fluctuations. The contemporary interconnectedness of societies serves as a conduit for introducing and establishing these infections, warranting comprehensive assessment. This study emphasizes the pivotal role of heightened clinician vigilance, judicious public health interventions, and synergistic research collaborations to mitigate the potential consequences of these infections. Though rare, their profound impact on morbidity and mortality underscores the collective urgency required to safeguard the neurological well-being of the European populace. Through this multifaceted approach, Europe can effectively navigate the complex terrain posed with these emergent infections.

Imaging features of fulminant cerebral malaria: A case report

Cerebral malaria is associated with high mortality and morbidity in patients infected with Plasmodium Falciparum. The mechanisms of cerebral malaria include sequestration of parasitized red blood cells in brain capillaries, production of cytokines, immune cell/platelet accumulation, and release of microparticles, resulting in disruption of the blood-brain barrier, which caused brain injuries. The severity of this reflects on neurological findings ranging from simple delirium to profound coma. We herein present unique magnetic resonance imaging findings of a case of fulminant cerebral malaria as computed tomography studies usually underestimate the extent of cerebral involvement in malaria.

Sparganosis of a thoracic vertebra misdiagnosed as bone metastasis from lung cancer

Sparganosis is a rare parasitic infection caused by plerocercoid tapeworm larvae. We described a case of a 27-year-old man presenting with numbness in both legs and masses in the right lung and spine, initially thought to have spinal metastasis from lung cancer. However, after pathological and parasitological examinations, the patient was found to have spinal sparganosis, likely due to a history of consuming raw frogs. The patient was successfully treated with praziquantel, resulting in the recovery of muscle strength in his legs. This case highlights the importance of considering spinal sparganosis as a differential diagnosis in patients with spinal masses, especially those with a history of consuming raw or undercooked frogs. Accurate diagnosis and early treatment are crucial for managing this infection.

Outbreak of Chagas disease in Brazil: Validation of a molecular diagnostic method

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi (T. cruzi), affects millions of people worldwide. Polymerase Chain Reaction (PCR) and real-time quantitative PCR (qPCR) have been used as tools to monitor parasitic levels in the bloodstream of individuals exposed to infection, thus enabling the monitoring of relapses and the effectiveness of therapy, for example. The aim of this study was to evaluate the TcSAT-IAM system, developed by our research group, on samples from patients with suspected Chagas disease infection. Initially, primer systems were developed for the detection of the nuclear DNA (SAT-DNA) from T. cruzi (TcSAT-IAM). The Cruzi system, predicted in the literature, and TcSAT-IAM were then evaluated in relation to their analytical sensitivity, specificity and efficiency. Afterwards, the applicability of the qPCR technique using both systems (separately) for the diagnosis of acute CD was evaluated in samples from 77 individuals exposed to the outbreak that occurred in Pernambuco-Brazil, relating the results obtained to those of the classical diagnostic methods recommended for this stage of the infection. TcSAT-IAM and Cruzi had a detection limit of 1 fg of target DNA (0,003 parasites). Thirty-eight cases were recorded, 28 by laboratory criteria and 10 by clinical and epidemiological criteria. Blood samples from 77 subjects were submitted to qPCR by both systems, reaching an agreement of 89.61% between them. After analyzes between systems and diagnostic criteria, the TcSAT-IAM showed sensitivity and specificity of 52.36% (CI 37.26-67.52) and 92.31% (CI 79.68-97.35), respectively, accuracy of 72.73% and moderate agreement. The TcSAT-IAM showed an accuracy of 72.58% and 75% in relation to parasitological and serological tests (IgM anti-T. cruzi), respectively. Therefore, quantitative PCR should be incorporated into the diagnosis of suspected acute cases of Chagas disease.

A case of cerebral paragonimiasis misdiagnosed as eosinophilic granulomatosis with polyangiitis

Paragonimiasis is a parasitic disease caused by Paragonimus westermani infection, and migration to the brain results in cerebral paragonimiasis. Cerebral paragonimiasis is now extremely rare, but a few cases are still reported. A 48‐year‐old Japanese woman presented with right‐hand convulsion, right‐hand numbness, sputum, and fatigue. Chest computed tomography demonstrated multiple nodular lesions, and head computed tomography revealed a hemorrhagic lesion in the left motor cortex. Magnetic resonance imaging revealed multiple small ring‐shaped lesions with surrounding edema. Laboratory evaluation demonstrated peripheral eosinophilia. We considered eosinophilic granulomatosis with polyangiitis and started steroid treatment as a diagnostic therapy since we wanted to avoid cerebral lesion biopsy if possible. However, the patient underwent craniotomy surgery after steroid treatment for four months because a new intracerebral mass lesion had appeared. Trematode eggs were detected in the sample, and the final diagnosis was cerebral paragonimiasis. The patient was successfully treated with praziquantel. Cerebral paragonimiasis is extremely rare but should be considered in the differential diagnosis if atypical intracranial hemorrhage and peripheral eosinophilia are observed.

Neuroimmunology of Common Parasitic Infections in Africa

Parasitic infections of the central nervous system are an important cause of morbidity and mortality in Africa. The neurological, cognitive, and psychiatric sequelae of these infections result from a complex interplay between the parasites and the host inflammatory response. Here we review some of the diseases caused by selected parasitic organisms known to infect the nervous system including Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei spp., and Taenia solium species. For each parasite, we describe the geographical distribution, prevalence, life cycle, and typical clinical symptoms of infection and pathogenesis. We pay particular attention to how the parasites infect the brain and the interaction between each organism and the host immune system. We describe how an understanding of these processes may guide optimal diagnostic and therapeutic strategies to treat these disorders. Finally, we highlight current gaps in our understanding of disease pathophysiology and call for increased interrogation of these often-neglected disorders of the nervous system.

A restored humoral environment ameliorates acute brain injury after Angiostrongylus cantonensis infection

Circulating factors in the circulatory system support important functions of living tissues and the body. Parabiosis is a condition in which two living animals are connected using surgical methods and share a single circulatory system. Angiostrongylus cantonensis is the major cause of infectious eosinophilic meningitis, which causes severe damage to the central nervous system (CNS) and immune system. However, the mechanism of immunopathology remains largely unknown. We hypothesize that a restored humoral environment can help relieve damage to the CNS and immune system. In the present study, we found that administration of normal serum significantly reduced mortality, alleviated thymic atrophy and reduced inflammation in the brains of mice infected with A. cantonensis. We further generated parabiotic pairs between two healthy mice, one of which was then orally infected with A. cantonensis. The results showed that compared with singleton mice, mice connected with a healthy parabiotic partner were protected against CNS and immune system damage, as revealed by significantly reduced inflammation in the brain, alleviated thymic atrophy, and decreased expression of proinflammatory cytokines. These findings revealed that a healthy systemic environment can relieve damage to the CNS and immune system in infected mice, suggesting novel therapeutic approaches for diseases involving severe brain and immune system damage.

Mechanisms of the host immune response and helminth-induced pathology during Trichobilharzia regenti (Schistosomatidae) neuroinvasion in mice

Helminth neuroinfections represent serious medical conditions, but the diversity of the host-parasite interplay within the nervous tissue often remains poorly understood, partially due to the lack of laboratory models. Here, we investigated the neuroinvasion of the mouse spinal cord by Trichobilharzia regenti (Schistosomatidae). Active migration of T. regenti schistosomula through the mouse spinal cord induced motor deficits in hindlimbs but did not affect the general locomotion or working memory. Histological examination of the infected spinal cord revealed eosinophilic meningomyelitis with eosinophil-rich infiltrates entrapping the schistosomula. Flow cytometry and transcriptomic analysis of the spinal cord confirmed massive activation of the host immune response. Of note, we recorded striking upregulation of the major histocompatibility complex II pathway and M2-associated markers, such as arginase or chitinase-like 3. Arginase also dominated the proteins found in the microdissected tissue from the close vicinity of the migrating schistosomula, which unselectively fed on the host nervous tissue. Next, we evaluated the pathological sequelae of T. regenti neuroinvasion. While no demyelination or blood-brain barrier alterations were noticed, our transcriptomic data revealed a remarkable disruption of neurophysiological functions not yet recorded in helminth neuroinfections. We also detected DNA fragmentation at the host-schistosomulum interface, but schistosomula antigens did not affect the viability of neurons and glial cells in vitro. Collectively, altered locomotion, significant disruption of neurophysiological functions, and strong M2 polarization were the most prominent features of T. regenti neuroinvasion, making it a promising candidate for further neuroinfection research. Indeed, understanding the diversity of pathogen-related neuroinflammatory processes is a prerequisite for developing better protective measures, treatment strategies, and diagnostic tools.

Detection of Toxocara cati Larvae from Ostrich and Wild Boar Meat Intended for Human Consumption

Toxocara cati is a common roundworm of cats and wild felids and, together with T. canis, it is the main causative agent of human toxocariasis. Humans may become infected by ingestion of embryonated eggs via contaminated soil, food, or water, or by ingestion of raw or undercooked meat of paratenic hosts that are infected by Toxocara larvae. In this study, we report the detection of T. cati larvae from meat samples of ostriches and wild boars. These samples were inspected by enzymatic digestion, as part of the trichinellosis surveillance. As ostrich meat is intended for “carpaccio” preparation, a traditional Italian raw meat preparation, there is the need to make the consumption of this meat safe. For this purpose, it is recommended to freeze the meat before preparation. Our findings confirmed that T. cati larvae can contaminate muscle tissues of paratenic hosts, increasing the risk of infection due to the consumption of raw or undercooked meat.

Development of Immunochromatographic Test Kit for Rapid Detection of Specific IgG4 Antibody in Whole-Blood Samples for Diagnosis of Human Gnathostomiasis

Human gnathostomiasis is a harmful food-borne zoonosis caused by roundworms of the genus Gnathostoma. The parasite can occasionally migrate to the central nervous system, causing life-threatening disease and death. Here, we report a new point-of-care (POC) test kit, the gnathostomiasis blood immunochromatographic test (GB-ICT) kit. The kit is based on recombinant Gnathostoma spinigerum antigen and detects specific IgG4 antibody in whole-blood samples (WBSs). The GB-ICT kit showed potentially high diagnostic values with simulated WBSs (n = 248), which were obtained by spiking patients’ sera with red blood cells. The accuracy, sensitivity, specificity, and positive and negative predictive values were 95.2%, 100%, 93.8%, 81.5%, and 100%, respectively. Ten WBSs from clinically suspected gnathostomiasis patients were all positive according to the GB-ICT kit, while 10 WBSs from healthy volunteers were negative. The GB-ICT kit is a simple and convenient POC testing tool using finger-prick blood samples: venous blood sampling and serum separation processes are not required. The GB-ICT kit can support clinical diagnosis in remote areas and field settings without sophisticated equipment facilities.

Application of Dendrimers for Treating Parasitic Diseases

Despite advances in medical knowledge, parasitic diseases remain a significant global health burden and their pharmacological treatment is often hampered by drug toxicity. Therefore, drug delivery systems may provide useful advantages when used in combination with conventional therapeutic compounds. Dendrimers are three-dimensional polymeric structures, characterized by a central core, branches and terminal functional groups. These nanostructures are known for their defined structure, great water solubility, biocompatibility and high encapsulation ability against a wide range of molecules. Furthermore, the high ratio between terminal groups and molecular volume render them a hopeful vector for drug delivery. These nanostructures offer several advantages compared to conventional drugs for the treatment of parasitic infection. Dendrimers deliver drugs to target sites with reduced dosage, solving side effects that occur with accepted marketed drugs. In recent years, extensive progress has been made towards the use of dendrimers for therapeutic, prophylactic and diagnostic purposes for the management of parasitic infections. The present review highlights the potential of several dendrimers in the management of parasitic diseases.

Model systems for studying polyphosphate biology: a focus on microorganisms

Polyphosphates (polyP) are polymers of inorganic phosphates joined by high-energy bonds to form long chains. These chains are present in all forms of life but were once disregarded as 'molecular fossils'. PolyP has gained attention in recent years following new links to diverse biological roles ranging from energy storage to cell signaling. PolyP research in humans and other higher eukaryotes is limited by a lack of suitable tools and awaits the identification of enzymatic players that would enable more comprehensive studies. Therefore, many of the most important insights have come from single-cell model systems. Here, we review determinants of polyP metabolism, regulation, and function in major microbial systems, including bacteria, fungi, protozoa, and algae. We highlight key similarities and differences that may aid in our understanding of how polyP impacts cell physiology at a molecular level.

The peripheral immune response of mice infected with a neuropathogenic schistosome

Trichobilharzia regenti (Schistosomatidae) percutaneously infects birds and mammals and invades their central nervous system (CNS). Here, we characterized the peripheral immune response of infected mice and showed how it was influenced by the parasite-induced inflammation in the skin and the CNS. As revealed by flow cytometry, T cells expanded in the spleen and the CNS-draining lymph nodes 7-14 days post-infection. Both T-bet+ and GATA-3+ T cells were markedly elevated suggesting a mixed type 1/2 immune response. However, it dropped after 7 dpi most likely being unaffected by the neuroinflammation. Splenocytes from infected mice produced a high amount of IFN-γ and, to a lesser extent, IL-10, IL-4 and IL-17 after in vitro stimulation by cercarial homogenate. Nevertheless, it had only a limited capacity to alter the maturation status of bone marrow-derived dendritic cells (BMDCs), contrary to the recombinant T. regenti cathepsin B2, which also strongly augmented expression of Ccl5, Cxcl10, Il12a, Il33 and Il10 by BMDCs. Taken together, mice infected with T. regenti developed the mixed type 1/2 immune response, which was driven by the early skin inflammation rather than the late neuroinflammation. Parasite peptidases might play an active role in triggering the host immune response.

Necroptosis and Caspase-2-Mediated Apoptosis of Astrocytes and Neurons, but Not Microglia, of Rat Hippocampus and Parenchyma Caused by Angiostrongylus cantonensis Infection

Infection with the roundworm Angiostrongylus cantonensis is the main cause of eosinophilic meningitis worldwide. The underlying molecular basis of the various pathological outcomes in permissive and non-permissive hosts infected with A. cantonensis remains poorly defined. In the present study, the histology of neurological disorders in the central nervous system (CNS) of infected rats was assessed by using hematoxylin and eosin staining. Quantitative reverse transcription polymerase chain reaction (RT-qPCR), western blot and immunofluorescence (IF) were used in evolutions of the transcription and translation levels of the apoptosis-, necroptosis-, autophagy-, and pyroptosis-related genes. The distribution of apoptotic and necroptotic cells in the rat hippocampus and parenchyma was further detected using flow cytometry, and the features of the ultrastructure of the cells were examined by transmission electron microscopy (TEM). The inflammatory response upon CNS infection with A. cantonensis evolved, as characterized by the accumulation of a small number of inflammatory cells under the thickened meninges, which peaked at 21 days post-infection (dpi) and returned to normal by 35 dpi. The transcription levels and translation of caspase-2, caspase-8, RIP1 and RIP3 increased significantly at 21 and 28 dpi but decreased sharply at 35 dpi compared to those in the normal control group. However, the changes in the expression of caspase-1, caspase-3, caspase-11, Beclin-1 and LC3B were not obvious, suggesting that apoptosis and necroptosis but not autophagy or pyroptosis occurred in the brains of infected animals at 21 and 28 dpi. The results of RT-qPCR, western blot analysis, IF, flow cytometry and TEM further illustrated that necroptosis and caspase-2-mediated apoptosis occurred in astrocytes and neurons but not in microglia in the parenchyma and hippocampus of infected animals. This study provides the first evidence that neuronal and astrocytic necroptosis and caspase-2-mediated apoptosis are induced by A. cantonensis infection in the parenchymal and hippocampal regions of rats at 21 and 28 dpi but these processes are negligible at 35 dpi. These findings enhance our understanding of the pathogenesis of A. cantonensis infection and provide new insights into therapeutic approaches targeting the occurrence of cell death in astrocytes and neurons in infected patients.

Current epidemic situation of human toxocariasis in China

Toxocariasis is a worldwide-distributed helminthic zoonosis, which mainly results from ascarid nematodes Toxocara canis and Toxocara cati. Humans become infected by accidental ingestion of infective eggs, raw or undercooked meat containing larvae. Keeping and contacting cats and dogs, and bad hygiene situations or habits are the main risk factors for Toxocara infection in China. The seroprevalence of Toxocara spp. is reported from 12.14% to 44.83%, and the overall seroprevalence in children was 12.14% in 1993 and elevated to 19.3% in 2015. Among the 103 cases reported in China during 1983-2019, ocular larva migrans (OLM), visceral larva migrans (VLM), and neural larva migrans (NLM) occupied 92.23%, 6.80%, and 0.97% of cases, respectively. The diagnosis of toxocariasis is mainly based on the history of exposure to infective eggs or larvae, clinical manifestations, laboratory examinations, and imaging studies. As most individuals who are infected with larval Toxocara, are unaware of their infections, patients with mild signs as described under covert toxocariasis (CT) can recover spontaneously, and treatment may not be necessary. Albendazole is the preferred treatment for patients with VLM; steroids, such as prednisolone combined with albendazole, are frequently used in treating patients with OLM, and surgery serves as an alternative treatment; thiabendazole is effective in treating patients with NLM. The true number of cases and prevalence of toxocariasis in China seems to be underestimated and neglected because of the lack of population-based epidemiological studies and insufficient clinical awareness of this disease, which are aspects that need to be improved by the Chinese government.

Bioinformatics Structural and Phylogenetic Characterization of Entamoeba histolytica Alcohol Dehydrogenase 2 (EhADH2)

An amitochondriate parasite, Entamoeba histolytica, has a bifunctional ADHE enzyme (EhADH2) that contains separate acetaldehyde (ALDH) and alcohol (ADH) dehydrogenase activities. In a cluster of 25 bifunctional enzymes of single cell eukaryotes and bacteria, we present a phylogenetic analysis that suggests a lateral gene transfer event (prokaryotic ancestor to single-cell eukaryotic ancestor) and a complex structure that aligns with key homologs in the ADHE evolutionary history based on their similarity with bacterial alcohol dehydrogenases. We show that the ADHE in Entamoeba lineage diverged independently but shows significant similarities to the structure of ADHE in Fusobacterium, and a complex model that maps its ALDH and ADH domain well with bacteria such as Geobaccillus thermoglucosidasius. Our analyses likely support a lateral acquisition of an EhADH2-like ancestral gene from bacteria. Several evolutionary analyses software programs reveal that the enzyme structure is highly conserved, and maintains a similar function within a diverse set of pathogens, including Escherichia coli and Clostridium spp.

Human toxocariasis - A look at a neglected disease through an epidemiological 'prism'

Toxocariasis, a disease caused by infection with larvae of Toxocara canis, T. cati and/or congeners, represents clinical syndromes in humans including visceral and ocular larva migrans, neurotoxocariasis and covert/common toxocariasis. It is reported to be one of the most widespread public health and economically important zoonotic parasitic infections that humans share with dogs, wild canids, including foxes, and possibly other mammals. Humans become infected by accidental ingestion of embryonated Toxocara eggs, or larvae from tissues from domestic or wild paratenic hosts. Most infections are asymptomatic, and human disease may go unnoticed, as clinical investigation is often not pursued and/or diagnostic testing not conducted. Sometimes toxocariasis can be associated with complications, such as allergic and/or neurological disorders, possibly including cognitive or developmental delays in children. There is no anti-toxocariasis vaccine, and chemotherapy in humans varies, depending on symptoms and location of larvae, and may include the administration of albendazole or mebendazole, together with anti-inflammatory corticosteroids. Some recent studies indicate that toxocariasis is having an increased, adverse impact on human health in some, particularly underprivileged, tropical and subtropical communities around the world. Although tens of millions of people, especially children, are expected to be exposed to, or infected with Toxocara species, there is limited precise epidemiological data or information on the relationship between seropositivity and disease (toxocariasis) on a global scale. To gain an improved insight into this area, the present article reviews salient clinical aspects of human toxocariasis and the epidemiology of this disease, with particular reference to seroprevalence, and discusses future research and approaches/measures to understand and prevent/control this socioeconomically important, yet neglected zoonosis.

Assessment of Parasite-Microglia Interactions In Vitro

An extensive number of parasites are able to invade the central nervous system (CNS) and cause a plethora of pathologies. Microglia, the resident macrophages of nervous tissue, are responsible for the protection against intruders, and therefore, they are an important line of defense against parasites. The phagocytosis is one of the weapons in the microglia's arsenal to fight against parasites. Several prior studies of microglia-parasite interactions and phagocytosis have been performed using microscopic techniques. As this methodology allows only a limited number of cells to be analyzed, additional approaches are required to provide a more complete picture of how microglia interact with these pathogens. Here, we describe a protocol based on flow cytometry to analyze single-celled parasites/microglia interactions in thousands of events in an accurate and reliable way. We use Trypanosoma brucei as a model organism, as it is a well-known parasite causing primary meningoencephalitis. However, the interaction/phagocytosis assay can be applied to other single-celled parasites as well.

Targeting the master regulator mTOR: a new approach to prevent the neurological of consequences of parasitic infections?

A systematic analysis of 240 causes of death in 2013 revealed that parasitic diseases were responsible for more than one million deaths. The vast majority of these fatalities resulted from protozoan infections presenting with neurological sequelae. In the absence of a vaccine, development of effective therapies is essential to improving global public health. In 2015, an intriguing strategy to prevent cerebral malaria was proposed by Gordon et al. 2015 mBio, 6:e00625. Their study suggested that inhibition of the mammalian target of rapamycin prevented experimental cerebral malaria by blocking the damage to the blood brain barrier and stopping the accumulation of parasitized red blood cells and T cells in the brain. Here, we hypothesize that the same therapeutic strategy could be adopted for other protozoan infections with a brain tropism, to prevent cerebral parasitosis by limiting pathogen replication and preventing immune mediated destruction of brain tissue.

Cerebrospinal fluid cytology in nonmalignant aseptic meningeal disorders

Cerebrospinal fluid cytology examination is a common and reliable primary and/or complementary procedure for the diagnosis of central nervous system (CNS) disorders. This review provides an update of aseptic meningeal disorders that may be encountered in cytopathology practice. The article covers the cytological findings and helpful ancillary studies needed of nonmalignant aseptic CNS disorders such as viral, bacterial, fungal and parasitic infections, and other noninfectious diseases, such as Mollaret's meningitis (recurrent benign lymphocytic meningitis), Guillain-Barré syndrome, multiple Sclerosis, subarachnoid haemorrhage, and drug-induced disorders.

Small rodents as paratenic or intermediate hosts of carnivore parasites in Berlin, Germany

Rodents are important intermediate and paratenic hosts for carnivore parasites, including the important zoonotic agents Toxoplasma, Echinococcus and Toxocara. Monitoring of such parasites in rodents can be used to detect increasing risks for human and veterinary public health. Rodents were trapped at four sites in Berlin, two near the city center, two at the periphery. PCRs were conducted to detect Coccidia (target ITS-1) and specifically Toxoplasma gondii (repetitive element) in brain and ascarids (ITS-2) in muscle or brain tissue. During necropsies, metacestodes were collected and identified using ITS-2 and 12S rRNA PCRs. An ELISA to detect antibodies against Toxocara canis ES antigens was performed. Within the 257 examined rodents, the most frequently observed parasite was Frenkelia glareoli predominantly found in Myodes glareolus. T. gondii was only detected in 12 rodents and Microtus spp. (although strongly underrepresented) had a significantly increased chance of being positive. Neither Echinococcus nor typical Taenia parasites of dogs and cats were found but Mesocestoides litteratus and Taenia martis metacestodes were identified which can cause severe peritoneal or ocular cysticercosis in dogs, primates and humans. Using PCR, the ascarids T. canis (n = 8), Toxocara cati (4) and Parascaris sp. (1) were detected predominantly in muscles. Seroprevalence of T. canis was 14.2% and ELISA was thus more sensitive than PCR to detect infection with this parasite. Non-parametric multidimensional scaling and cluster analysis revealed that parasite communities could be grouped into an urban and a peri-urban cluster with high frequency of ascarid-positive rodents in urban and high frequency of F. glareoli in peri-urban sites. Prevalence rates of parasites in rodents with potential impact for human or veterinary public health are considerable and the monitoring of transmission cycles of carnivore parasites in intermediate rodent hosts is recommended to estimate the health risks arising from wild and domesticated carnivores.

Mediators and Biomarkers of Inflammation in Meningitis: Cytokine and Peptidome Profiling of Cerebrospinal Fluid

Differential diagnosis of bacterial and viral meningitis is an urgent problem of the modern clinical medicine. Early and accurate detection of meningitis etiology largely determines the strategy of its treatment and significantly increases the likelihood of a favorable outcome for the patient. In the present work, we analyzed the peptidome and cytokine profiles of cerebrospinal fluid (CSF) of 17 patients with meningitis of bacterial and viral etiology and of 20 neurologically healthy controls. In addition to the identified peptides (potential biomarkers), we found significant differences in the cytokine status of the CSF of the patients. We found that cut-off of 100 pg/ml of IL-1β, TNF, and GM-CSF levels discriminates bacterial and viral meningitis with 100% specificity and selectivity. We demonstrated for the first time the reduction in the level of two cytokines, IL-13 and GM-CSF, in the CSF of patients with viral meningitis in comparison with the controls. The decrease in GM-CSF level in the CSF of patients with viral meningitis can be explained by a disproportionate increase in the levels of cytokines IL-10, IFN-γ, and IL-4, which inhibit the GM-CSF expression, whereas IL-1, IL-6, and TNF activate it. These observations suggest an additional approach for differential diagnosis of bacterial and viral meningitis based on the normalized ratio IL-10/IL-1β and IL-10/TNF > 1, as well as on the ratio IFN-γ/IL-1β and IFN-γ/TNF < 0.1. Our findings extend the panel of promising clinical and diagnostic biomarkers of viral and bacterial meningitis and reveal opposite changes in the cytokine expression in meningitis due to compensatory action of pro- and antiinflammatory factors.

Humans as Superorganisms: How Microbes, Viruses, Imprinted Genes, and Other Selfish Entities Shape Our Behavior

Psychologists and psychiatrists tend to be little aware that (a) microbes in our brains and guts are capable of altering our behavior; (b) viral DNA that was incorporated into our DNA millions of years ago is implicated in mental disorders; (c) many of us carry the cells of another human in our brains; and (d) under the regulation of viruslike elements, the paternally inherited and maternally inherited copies of some genes compete for domination in the offspring, on whom they have opposite physical and behavioral effects. This article provides a broad overview, aimed at a wide readership, of the consequences of our coexistence with these selfish entities. The overarching message is that we are not unitary individuals but superorganisms, built out of both human and nonhuman elements; it is their interaction that determines who we are.

Molecular analyses reveal two geographic and genetic lineages for tapeworms, Taenia solium and Taenia saginata, from Ecuador using mitochondrial DNA

Tapeworms Taenia solium and Taenia saginata are the causative agents of taeniasis/cysticercosis. These are diseases with high medical and veterinary importance due to their impact on public health and rural economy in tropical countries. The re-emergence of T. solium as a result of human migration, the economic burden affecting livestock industry, and the large variability of symptoms in several human cysticercosis, encourage studies on genetic diversity, and the identification of these parasites with molecular phylogenetic tools. Samples collected from the Ecuadorian provinces: Loja, Guayas, Manabí, Tungurahua (South), and Imbabura, Pichincha (North) from 2000 to 2012 were performed under Maximum Parsimony analyses and haplotype networks using partial sequences of mitochondrial DNA, cytochrome oxidase subunit I (COI) and NADH subunit I (NDI), from Genbank and own sequences of Taenia solium and Taenia saginata from Ecuador. Both species have shown reciprocal monophyly, which confirms its molecular taxonomic identity. The COI and NDI genes results suggest phylogenetic structure for both parasite species from south and north of Ecuador. In T. solium, both genes gene revealed greater geographic structure, whereas in T. saginata, the variability for both genes was low. In conclusion, COI haplotype networks of T. solium suggest two geographical events in the introduction of this species in Ecuador (African and Asian lineages) and occurring sympatric, probably through the most common routes of maritime trade between the XV-XIX centuries. Moreover, the evidence of two NDI geographical lineages in T. solium from the north (province of Imbabura) and the south (province of Loja) of Ecuador derivate from a common Indian ancestor open new approaches for studies on genetic populations and eco-epidemiology.

No association between latent toxoplasmosis and multiple body measures in U.S. adults

Toxoplasma gondii (Nicolle et Manceaux, 1908) is an intracellular parasite that can cause ongoing latent infection persisting for the duration of a non-definitive host's life. Affecting approximately one-third of the world's population, latent toxoplasmosis has been associated with neuropsychological outcomes and a previous report suggested an association between latent toxoplasmosis and adult height. Given the large number of people with latent toxoplasmosis and its potential associations with human height, we sought to better understand the association between latent toxoplasmosis and human morphology by evaluating seropositivity for T. gondii and multiple body measures reported in the National Health and Nutrition Examination Survey III (NHANES III) and in the more recent continuous NHANES data sets from the United States Centers for Disease Control and Prevention for which data on T. gondii are available. In these analyses, latent toxoplasmosis was not associated with any of the body measures assessed in the NHANES datasets even after taking into account interactions between latent toxoplasmosis and testosterone suggesting that in these samples, latent toxoplasmosis is not associated with adult morphology including height.

Seroprevalence of Toxocara spp. in a rural population in Central African Gabon

Toxocara spp. are zoonotic parasites with global distribution infecting humans by incidental ingestions of eggs shed in feces of dogs or cats. High seroprevalences have been reported from several regions of Africa, however data from the Central African region remain limited. Although several clinical entities caused by larvae of Toxocara spp. have been described, the public heath impact of this infection has so far often been neglected. This study was conducted to estimate the prevalence in a rural central African population. The population based study was performed in volunteers in a rural region of Gabon. A two-step testing approach was applied using an ELISA as screening test and a Western Blot (immunoblot) as confirmatory assay. Basic demographic data and risk factors were collected and compared between seropositive and negative participants. In total, 199 out of 332 serum samples were tested positive for Toxocara spp. antibodies (59.9%). After standardization for age to the overall Gabonese population seroprevalence was 53.6% (95% CI 48.2-59.0%). There was a trend towards higher seroprevalence in participants with agricultural activity. Seroprevalence of antibodies against Toxocara spp. is high in this rural population in Gabon. These results are comparable with previous reports from other sub-regions of Africa and add to our understanding of the epidemiology of toxocariasis in Africa. Given the high prevalence of toxocariasis in tropical regions, it may be speculated that clinically relevant presentations (e.g. visceral or ocular larva migrans syndrome) may occur in considerable numbers. A formal assessment of the burden of disease and the public health impact of human toxocariasis is therefore warranted.

Parasitic and rare spinal infections

The imaging features of spinal parasitic diseases and other rare infections are herein discussed. These diseases are distributed worldwide, with increased prevalence in areas with poor sanitary conditions and in developing countries. In nonendemic areas, sporadic cases may occur, consequent to increased international travel and immunocompromising conditions. Infectious diseases are usually treatable, and early detection is often crucial. A thorough comprehension of the imaging patterns associated with the clinical features, epidemiology, and laboratory results allows the radiologist to narrow down the options for differential diagnosis and facilitates the timely implementation of appropriate therapies.

Harnessing the Toxocara Genome to Underpin Toxocariasis Research and New Interventions

Parasitic worms, such as flatworms (platyhelminths) and roundworms (nematodes), cause substantial morbidity and mortality in animals and people globally. The ascaridoid nematode Toxocara canis is a zoonotic parasite of socioeconomic significance worldwide. In humans, this worm causes toxocariasis (disease) mainly in underprivileged communities in both the developed and developing worlds. While reasonably well studied from clinical and epidemiological perspectives, little is understood about the molecular biology of T. canis, its relationship with its hosts and the disease that it causes. However, a recent report of the draft genome and transcriptomes of T. canis should underpin many fundamental and applied research areas in the future. The present article gives a background on Toxocara and toxocariasis, a brief account of diagnostic approaches for specific identification and genetic analysis, and gives a perspective on the impact that the genome of T. canis and advanced molecular technologies could have on our understanding of the parasite and the diseases that it causes as well as the design of new and improved approaches for the diagnosis, treatment and control of toxocariasis.

Infection and Stroke: an Update on Recent Progress

The role of infection in cerebrovascular disease is complex and remains incompletely understood. Over the last 5 years, investigators have made notable inroads in untangling this thorny topic. In this review, we examine these recent developments, concentrating on four aspects of the relationship between infection and stroke. We first discuss specific infectious agents as direct causes of stroke, focusing on recent work implicating herpesviruses and HIV in cerebral vasculopathy. We then discuss systemic infection of any type as a stroke trigger, focusing on the relationship of infection to timing of acute stroke, both in children and adults, as well as the role of vaccination in stroke prevention. We examine the evidence for chronic infection or "infectious burden" as a stroke risk factor. Finally, we discuss recent work on infection as a risk factor for increased morbidity after stroke, possible mechanisms mediating this effect, and the evidence for prophylactic antibiotics.

Lack of Association between Toxocara Exposure and Suicide Attempts in Psychiatric Patients

Infection with Toxocara may affect the central nervous system. A high seroprevalence of Toxocara infection has been reported in psychiatric patients. To the best of our knowledge, there is no previous report about an association of Toxocara infection with suicide attempts. Therefore, we sought to determine whether Toxocara exposure is associated with suicide attempts in psychiatric patients. We studied 282 psychiatric outpatients (156 with suicide attempts and 126 without suicide attempts). Sera of patients were analyzed for the presence of anti-Toxocara IgG antibodies by using a commercially available enzyme immunoassay. One of the 156 (0.6%) suicide attempters and 1 (0.8%) of the 126 controls were positive for anti-Toxocara IgG antibodies (OR = 0.80; 95% CI: 0.04–13.02; P = 1.00). Toxocara seropositivity was significantly higher (P = 0.01) in male patients with consumption of raw dried goat meat than male patients without this consumption. Results suggest that Toxocara exposure is not associated with suicide attempts in psychiatric outpatients in Durango City, Mexico. However, further studies with larger samples sizes to confirm our results should be conducted. Too few patients were seropositive to assess further associations of Toxocara exposure with sociodemographic, clinical, and behavioral characteristics of the psychiatric patients.

Temporal-spatial pathological changes in the brains of permissive and non-permissive hosts experimentally infected with Angiostrongylus cantonensis

Human cerebral angiostrongyliasis becomes an emerging disease in many parts of the world. By postmortem examination, Angiostrongylus cantonensis have been reported to cause severe pathological changes in the central nervous system. The present study was designed to determine the temporal-spatial pathological changes through experimental infections and histopathological examination of permissive (SD rats) and non-permissive (ICR mice) hosts. After infecting SD rats with 25, 50, or 100 third-stage larvae (L3) and ICR mice with 25 L3, one animal from each group was sacrificed daily from day 1 to day 30 post-infection. Each rat brain was cut into six sections and mouse brain into five sections. These sections were stained with haematoxylin and eosin and examined microscopically. Eosinophilic meningitis was found to be the most commonly pathological change and occurred on day 17 post-infection in rats with 25 L3, day 9 in the 50- or 100-L3 groups, and day 12 in infected mice. Thickness of the meninges increased 9-24 folds in infected rats and 89 folds in an infected mouse on day 28. Encephalitis, congestion, perivascular cuffing, and haemorrhage were revealed in infected mice and rats with 100 L3. Fifth-stage larvae were frequently observed in the meninges but occasionally in the parenchyma. Significant correlations between meningitis and presence of larvae in the meninges were found in the three infected rat groups but not in the infected mice. The results indicate that the clinical course of A. cantonensis infection is not self-limited but becomes more severe with the intensity of infection.

Gnathostoma spinigerum Mitochondrial Genome Sequence: a Novel Gene Arrangement and its Phylogenetic Position within the Class Chromadorea

Human gnathostomiasis is an emerging food-borne parasitic disease caused by nematodes in the genus Gnathostoma. In spite of their significance as pathogens, these parasites remain poorly understood at the molecular level. In the present study, we sequenced the mitochondrial (mt) genome of G. spinigerum, which infects a range of definitive hosts including dogs, cats, tigers, leopards and humans. The mt genome of G. spinigerum is 14,079 bp in size and shows substantial changes in gene order compared to other nematodes studied to date. Phylogenetic analyses of mt genome sequences by Bayesian inference (BI) revealed that the infraorder Gnathostomatomorpha (represented by G. spinigerum) is closely related to the infraorder Ascaridomorpha. G. spinigerum is the first species from the infraorder Gnathostomatomorpha for which a complete mt genome has been sequenced. The new data will help understand the evolution, population genetics and systematics of this medically important group of parasites.

Pathologic approach to spinal cord infections

The pathologic evaluation of spinal cord infections requires comprehensive clinical, radiological, and laboratory correlation, because the histologic findings in acute, chronic, or granulomatous infections rarely provide clues for the specific cause. This brief review focuses on the pathologic mechanisms as well as practical issues in the diagnosis and reporting of infections of the spinal cord. Examples are provided of the common infectious agents and methods for their diagnosis. By necessity, discussion is restricted to the infections of the medulla spinalis proper and its meninges, and not bone or soft tissue infections.

Toxoplasmosis and epilepsy--systematic review and meta analysis

BACKGROUND

Toxoplasmosis is an important, widespread, parasitic infection caused by Toxoplasma gondii. The chronic infection in immunocompetent patients, usually considered as asymptomatic, is now suspected to be a risk factor for various neurological disorders, including epilepsy. We aimed to conduct a systematic review and meta-analysis of the available literature to estimate the risk of epilepsy due to toxoplasmosis.

METHODS

A systematic literature search was conducted of several databases and journals to identify studies published in English or French, without date restriction, which looked at toxoplasmosis (as exposure) and epilepsy (as disease) and met certain other inclusion criteria. The search was based on keywords and suitable combinations in English and French. Fixed and random effects models were used to determine odds ratios, and statistical significance was set at 5.0%.

PRINCIPAL FINDINGS

Six studies were identified, with an estimated total of 2888 subjects, of whom 1280 had epilepsy (477 positive for toxoplasmosis) and 1608 did not (503 positive for toxoplasmosis). The common odds ratio (calculated) by random effects model was 2.25 (95% CI 1.27-3.9), p = 0.005.

CONCLUSIONS

Despite the limited number of studies, and a lack of high-quality data, toxoplasmosis should continue to be regarded as an epilepsy risk factor. More and better studies are needed to determine the real impact of this parasite on the occurrence of epilepsy.

Helminths and helminthoses in Central Europe: diseases caused by cestodes (tapeworms)

The second part of the overview "Helminths and helminthoses in Central Europe" is dedicated to the cestodes (tapeworms) and the diseases caused by cestodes. The overview comprises the spectrum of the most relevant species, describes their incidence, geographic distribution and the most important clinical symptoms and highlights the possibilities of diagnosis, treatment and prophylaxis of cestode-caused diseases.

Multiple zoonotic parasites identified in dog feces collected in Ponte de Lima, Portugal-a potential threat to human health

Dogs play many roles and their presence within people’s houses has increased. In rural settings dog faeces are not removed from the streets, representing an environmental pollution factor. Our aim was to evaluate the occurrence of environmental contamination with zoonotic intestinal parasites of three groups of dogs in Ponte de Lima, Portugal, with a particular emphasis on Echinococcus granulosus. We collected 592 dog faecal samples from the environment, farm and hunting dogs. Qualitative flotation coprological analysis was performed and the frequency in the positive samples ranged between 57.44% and 81.19% in different groups. We isolated up to four different parasites in one sample and detected seven intestinal parasitic species, genera or families overall. Ancylostomatidae was the most prevalent parasite, followed by Trichuris spp., Toxocara spp., Isospora spp., Dipylidium caninum, Taeniidae and Toxascaris leonina. Taeniidae eggs were analyzed with the PCR technique and revealed not to be from Echinococcus. The parasite prevalence and the diversity of zoonotic parasites found were high, which calls for a greater awareness of the problem among the population, especially hunters. Promoting research at the local level is important to plan control strategies. Health education should be developed with regard to farmers and hunters, and a closer collaboration between researchers, practitioners and public health authorities is needed.

Timing of Pharyngeal Swallow Events in Chagas' Disease

Background

Esophageal involvement by Chagas’ disease causes a significative decrease in the number of neurons of the esophageal myenteric plexus, causing an impairment of esophageal motility with the same alterations described in primary esophageal achalasia. There is also a longer duration of pharyngeal transit, which might be consequent of the involvement of the central control of swallowing by the disease, or an adaptation of the pharynx to the difficult bolus transit through the esophagus, which could contribute to the complaint of dysphagia.

Methods

We studied, by videofluoroscopy, the sequence and timings of pharyngeal bolus transit in 16 patients with esophageal involvement by Chagas’ disease and 12 healthy volunteers. Each subject swallowed in duplicate 5 mL and 10 mL of liquid and paste boluses.

Results

There was no difference between Chagas’ disease patients and normal volunteers in the sequence and timing of events associated with pharyngeal bolus flow, for liquid and paste boluses, and for 5 mL and 10 mL.

Conclusion

The timing and sequence of swallow pharyngeal events of patients with Chagas’ disease do not differ from that of control subjects, which suggested that the central control of swallowing is not impaired by the disease.

Cutaneous gnathostomiasis with recurrent migratory nodule and persistent eosinophilia: a case report from China

The present study reports a human case of cutaneous gnathostomiasis with recurrent migratory nodule and persistent eosinophilia in China. A 52-year-old woman from Henan Province, central China, presented with recurrent migratory reddish swelling and subcutaneous nodule in the left upper arm and on the back for 3 months. Blood examination showed eosinophila (21.2%), and anti-sparganum antibodies were positive. Skin biopsy of the lesion and histopathological examinations revealed dermal infiltrates of eosinophils but did not show any parasites. Thus, the patient was first diagnosed as sparganosis; however, new migratory swellings occurred after treatment with praziquantel for 3 days. On further inquiring, she recalled having eaten undercooked eels and specific antibodies to the larvae of Gnathostoma spinigerum were detected. The patient was definitely diagnosed as cutaneous gnathostomiasis caused by Gnathostoma sp. and treated with albendazole (1,000 mg/day) for 15 days, and the subsequent papule and blister developed after the treatment. After 1 month, laboratory findings indicated a reduced eosinophil count (3.3%). At her final follow-up 18 months later, the patient had no further symptoms and anti-Gnathostoma antibodies became negative. Conclusively, the present study is the first report on a human case of cutaneous gnathostomiasis in Henan Province, China, based on the past history (eating undercooked eels), clinical manifestations (migratory subcutaneous nodule and persistent eosinophilia), and a serological finding (positive for specific anti-Gnathostoma antibodies).