Evidence for Asthma in the Lungs of Mice Inoculated with Different Doses of Toxocara canis.

Toxocara canis, a common roundworm that mainly causes toxocariasis, is a zoonotic parasite found worldwide. Humans, an accidental host, can acquire T. canis infection through accidental ingestion of T. canis-embryonated egg-contaminated food, water, and soil, and by encapsulated larvae in a paratenic host's viscera or meat. Long-term residence of T. canis larvae in a paratenic host's lungs may induce pulmonary inflammation that contributes to lung injury, airway inflammatory hyperresponsiveness, and collagen deposition in mice and clinical patients. This study intended to investigate the relationship between T. canis infection and allergic asthma in BALB/c mice inoculated with high, moderate, and low doses of T. canis eggs for a 13-week investigation. The airway hyperresponsiveness (AHR) to methacholine, collagen deposition, cytokine levels, and pathological changes in lung tissues was assessed in infected mice at weeks 1, 5, and 13 postinfection. The cell composition in bronchoalveolar lavage fluid of infected mice was assessed at weeks 5 and 13 postinfection. Compared with uninfected control mice, all groups of T. canis-infected mice exhibited significant AHR, a dose-dependent increase in eosinophilic infiltration leading to multifocal interstitial and alveolar inflammation with abundant mucus secretion, and collagen deposition in which the lesion size increased with the infective dose. Infected mice groups also showed significant expressions of eotaxin and type 2 T-helper-dominant cytokines such as interleukin (IL)-4, IL-5, and IL-13. Overall, these results suggest that T. canis larval invasion of the lungs may potentially cause pulmonary inflammatory injury and could subsequently contribute to the development of allergic manifestations such as asthma.

Toxocariasis of the Nervous System.

PURPOSE: Toxocariasis is a helminthozoonosis caused by the infection of a human host by the larva of Toxocara spp., predominately involving Toxocara canis and Toxocara cati, which are common nematodes in dogs and cats, respectively. Human transmission occurs through contact with animals or by consumption of food contaminated with parasite's eggs. The purpose of this article is to review the current knowledge regarding human neurotoxocariasis. METHODS: We conducted a systematic review of the existing literature concerning toxocariasis of the nervous system. RESULTS: Clinical spectrum of human toxocariasis varies widely from a subclinical course to significant organ morbidity. Clinical course depends on parasitic load, the migration route of the larvae and host response. Human neurotoxocariasis is a relatively rare entity yet associated with severe sequelae. Manifestations include meningitis (usually eosinophilic), encephalitis, myelitis, cerebellar vasculitis, space-occupying lesion, behavioral abnormalities, and optic neuritis. Even though valid diagnostic criteria are lacking, neurotoxocariasis should be suspected in patients with neurologic symptoms and cerebrospinal fluid (CSF) pleocytosis with eosinophilia, positive serology for anti-Toxocara antibodies, in serum and/or CSF, sterile CSF and clinical improvement after antihelminthic treatment. Neurotoxocariasis is treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine. CONCLUSION: Parasite larvae migrate through tissues and are able to reach the nervous system causing neurotoxocariasis. Its clinical spectrum varies and includes myelitis, meningoencephalitis, brain abscess, and vasculitis. Neurotoxocariasis should always be suspected in patients with neurologic symptoms accompanied by eosinophilia in blood and/or CSF. Early diagnosis and treatment could prevent long-term neurologic impairment.

Clinical Features of Toxocara-Seropositive Optic Neuritis in Korea.

Purpose: This study was undertaken to analyze the characteristics of optic neuritis in Korean patients seropositive for Toxocara. Methods: We retrospectively reviewed data from patients diagnosed with optic neuritis and followed up for at least one month between 2012 and 2016. Patients were grouped according to Toxocara serological testing outcomes (positive or negative) and clinical characteristics were compared. Results: The seropositive and seronegative groups comprised 13 and 12 patients, respectively. The seropositive patients were older (56.8 years versus 34.5 years), reported ocular pain less frequently (30.8% versus 91.7%), and showed more frequent asymmetric optic disc swelling (72.7% versus 22.2%). During follow-up, visual acuity of all seronegative patients improved to 20/40 or better, compared with 38.5% of the seropositive group. Conclusion: Atypical features such as painless, older age, or asymmetric disc swelling in optic neuritis may be related to seropositivity for Toxocara, suggesting the possibility of undiagnosed Toxocara optic neuropathy.

Seroprevalence of ToxocaraCanis in Asthmatic Children and its Relation to the Severity of Diseases - a Case-Control Study.

Background: Toxocariasis is a common parasitic infectionworldwide even in developed countries. Through this health problem, the immune system is triggered and the antibody is produced, leading to some hypersensitive situations like asthma. In the present study, we tried to show a correlation between Toxocara Canis (T. canis) seropositivityand asthma in Isfahan city. Methods: This research is a cross-sectional study involving 40 asthmatics and 46 non-asthmatic cases aged 2-18 years. In all cases, T. canis IgG level was measured using enzyme-linked immunosorbent assay (ELISA) and compared between two groups. Results: The seroprevalence of IgG anti-T. canis antibodies were 45%in the asthmatic patients and 21.7% in thecontrols (P= 0.022). The more severe asthmatic patients had significantly more risk for T. canis seropositivity (P= 0.019). In the asthmatic patients, there was a significant correlation between Toxocara seropositivity and goingto park or playground (P= 0.001). Conclusion: In this study, we found a significantly positive serology of T. canis in asthmatic children especially in more severe disease. To verify the etiologic role of Toxocara in asthma, more advanced studies are needed.

Endocrine immune interactions during chronic Toxocariasis caused by Toxocara canis in a murine model: New insights into the pathophysiology of an old infection.

Toxocara canis is the helminth causing Toxocariasis, a parasitic disease with medical and veterinary implications. Their final host are members of the family Canidae and as paratenic hosts, most of the mammals are sensitive (man, rat, mouse, among others). It has been reported that a pituitary hormone, prolactin, it is responsible for reactivation and migration of larvae to the uterus and mammary gland during the last third of gestation in bitches. In addition, this hormone has been shown to play an important role in the regulation of the immune response. Thus, the aim of this study, was to evaluate the effect of hypophysectomy in the rat model of Toxocariasis, on the immune response against this parasite during a chronic infection, for which parasite loads were analyzed in different organs (lung and brain). Furthermore, serum specific antibody titers, and percentages of different cells of the immune system were also determined. The results showed a decrease in the number of larvae recovered from lung and brain in the hypophysectomized animals. In this same group of animals, there was no production of specific antibodies against the parasite. As for the percentages of the cells of the immune system, there are differences in some subpopulations due to surgery and others due to infection. Our results demonstrated that the lack of pituitary hormones alters parasite loads and the immune response to the helminth parasite Toxocara canis.

Ocular Toxocariasis: Clinical Features and Long-term Visual Outcomes in Adult Patients.

PURPOSE: To investigate clinical characteristics and treatment outcomes of proven ocular toxocariasis (OT) in adult patients. DESIGN: Retrospective, consecutive, interventional case series. METHODS: setting: Institutional. STUDY POPULATION: Consecutive OT patients with positive serum serology and positive western blot (WB) on ocular sample. OBSERVATION PROCEDURES: Clinical features, optical coherence tomography (OCT), and treatment outcomes. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) and OCT central foveal thickness (CFT). RESULTS: Fourteen patients were included between 2011 and 2013. Mean age at diagnosis was 45.6 years. Mean duration between the first symptoms and diagnosis was 15.1 months. Uveitis was unilateral in all cases and all patients displayed vitreous inflammation. The main baseline findings were presence of ≥1 peripheral granulomas (57.1%), vasculitis (57.1%), vitreoretinal traction (57.1%), and chronic macular edema (ME) (71.4%). Delayed diagnosis (>8 months) seemed to be associated with higher rate of ME. All patients received albendazole. Systemic (n = 5) and/or local corticosteroids (CS) (n = 7) were administered in case of ME and/or posterior segment inflammation. Vitrectomy was performed when vitreous inflammation was severe and persistent despite CS or in case of threatening traction or visually significant epimacular membrane (28.6%). Overall, this regimen allowed significant decrease of CFT (P = .01). In the vitrectomy subgroup, mean BCVA increased (P = .01) and CFT decreased (P = .017). CONCLUSION: While some features such as granuloma are typical signs of OT, atypical features can delay the diagnosis. In doubtful situations, WB on ocular samples seems to be more specific than serum antibodies alone. ME seems to be a common complication of longstanding OT in the adult.

Clinical Characteristics of Pediatric Patients with Ocular Toxocariasis in China.

OBJECTIVE: The aim of the study was to analyze the clinical characteristics of pediatric patients with ocular toxocariasis. METHODS: Ocular toxocariasis was diagnosed and treated in 46 children from Shanghai and surrounding provinces. The diagnosis of ocular toxocariasis was confirmed immunologically by performing an enzyme-linked immunosorbent assay on serum and/or intraocular fluid. All pediatric patients and their guardians completed a questionnaire concerning their cases and living habits. RESULTS: The mean age of onset was 6 ± 3 years. Most children (85%) resided in rural areas, and 91% of the children had contact with adult dogs or puppies. At the first visit, visual acuity (VA) was <20/200 in 36 cases, and we detected peripheral granuloma in 36 patients. In our study, the most common signs were vitritis, vitreous strands, and tractional retinal detachment. The Optomap 200Tx device detected granuloma with an 85% sensitivity, which is much higher than that of other techniques. We treated 40 cases (87%) with topical corticosteroids, while 28 patients (61%) were treated with systemic corticosteroids. Only 18 children (39%) required surgical intervention. All patients were examined and treated by the same ophthalmologists. CONCLUSIONS: Preschool children in China are more often affected by toxocariasis compared with other age groups. The most common signs included unilateral granuloma and ocular inflammation. In our study, clinical manifestations were severe and complicated. At the first visit, VA was <20/200 in most patients. Ocular toxocariasis was diagnosed on the basis of clinical signs and symptoms; the diagnosis was confirmed by immunological testing. Techniques using the Optomap 200Tx device can facilitate the early detection and lead to better visual prognosis.

Toxocariasis-associated cardiac diseases--A systematic review of the literature.

Toxocariasis, caused by Toxocara canis or Toxocara catis, is a worldwide occurring parasitic disease, reaching high prevalences especially in tropical and subtropical countries. The clinical presentation can range from asymptomatic seropositivity to life threatenting disease, depending on the organ system involved. Cardiac involvement, one of the possible manifestations of human Toxocara spp. infection, is rarely reported in case reports. As far as we know, no systematic reviews of clinical presentations have been published till now and no clear recommendations regarding the treatment of Toxocara spp. infection involving the heart exist. In a systematic review of the literature, 24 published cases of Toxocara spp. infection involving the heart were identified. The cardiac entities described included myocarditis, pericarditis, and Loeffler's endocarditis. The clinical presentation ranged from asymptomatic or mild disease to life threatening myocarditis/pericarditis with heart failure or cardiac tamponade, leading to death. In most cases, the diagnosis was based on a combination of clinical, laboratory and radiological findings. Only in three of the nine cases in which histological analysis was performed (either pre- or post-mortem), granulomas or remnants of the parasite were detected. In the other six cases, findings were non-specific; the damage of the heart was equally caused by direct invasion of the larvae and by immunological reactions, either caused by the systemic hypereosinophilia or by the presence of the larvae in the tissue. The treatment regimen described mostly consisted of anthelmintic drugs in combination with corticosteroids. Even though dosage and duration of treatment varied widely, ranging from days to months, most patients were treated successfully. Cardiac involvement in Toxocara spp. infection is a rare but potentially life-threatening complication of a very common disease. The therapeutic regimens vary widely especially with regard to the duration of therapy, however, the combination of an anthelmintic drug and a corticosteroid appears to be a valuable option. For the daily clinical work, tissue manifestation by parasites should be considered in cases of unspecific organ manifestations, (i.e. heart, lungs, liver), accompanied by fever and eosinophilia with or without allergic skin rashes.

Prevalence and Associated Risk Factors of Toxocara vitulorum Infections in Buffalo and Cattle Calves in Three Provinces of Central Cambodia.

The prevalence and associated risk factors of Toxocara vitulorum infection in buffalo and cattle calves was studied in 3 provinces in central Cambodia. Fecal samples were collected from 517 calves between the age of 1-15 weeks and processed for nematode egg counts by a modified McMaster method. A total of 64 calves were found to excrete T. vitulorum eggs in their feces (12.4%; 95% exact CI: 9.7-15.5). The mean fecal egg count was 2,798 EPG (SD=16,351; range=0-224,400). A multivariable generalized linear mixed model showed higher odds of T. vitulorum infection for buffalo versus cattle, for animals aged 4-8 weeks versus younger and older ones, and for animals with strongyle infection. There was no association with fecal consistency. Farmers should be aware of the potential impact of T. vitulorum , and treat their calves at the age of 2-3 weeks with anthelmintics such as benzimidazoles or pyrantel.

[SOME CLINICAL AND CYTOKINE FEATURES OF THE CLINICAL COURSE OF RECURRENT RESPIRATORY SYSTEM DISEASES IN CHILDREN WITH THE TOXOCARIASIS INVASION].

The aim of the present study was to analyze clinical and cytokine features of recurrent respiratory system diseases in children with toxocariasis. 50 children aged 1 to 17 years (mean age - 10±5 years) with recurrent current of respiratory system disorders were studied. During the survey such clinical manifestations of the respiratory system disorders as obstructive bronchitis (50%), bronchial asthma (30%), pneumonia (10%) and laryngotracheitis (10%) have been revealed. Statistical analysis of the results was performed using the software package STATISTICA 6.1 (SNANSOFT). We have shown that the disorders of respiratory system in case of toxocariasis invasion often occur with severe intoxication and bronchial obstruction syndromes, temperature reaction, respiratory insufficiency and hepatomegaly. A prolonged course of the disease has been noted. "Inflammatory" indicators of general blood analysis, such as leukocytosis and increased of ESR have been recorded in patients with respiratory system disorders in children with T.canis infection significantly more often, significant "allergic" laboratory changes were in the form of eosinophilia. High average levels of pro-inflammatory IL-6, as well as low levels of IL 5 have been determined in children suffering from the respiratory system disorders and with toxocariasis invasion in the anamnesis. The obtained findings require further study.

Manifestaciones cardiovasculares de la toxocariasis humana / Cardiovascular manifestations of human toxocariasis

La toxocariasis es una infección parasitaria producida por un helminto que en el ser humano no alcanza su estadio adulto. El hombre es para sus especies, Toxocara canis y Toxocara cati, un hospedador paraténico. Dicha infección puede producir el síndrome de larva migrans visceral, el síndrome de larva migrans ocular y la toxocariasis inaparente. En el síndrome de larva migrans visceral el compromiso de órganos puede incluir hígado, pulmón, piel, sistema nervioso, musculoesquelético, riñón y corazón. Sobre este último, cada vez se reconoce más la importancia que pueden tener las manifestaciones cardiovasculares de la toxocariasis y la relevancia clínica de considerarlas. En el presente artículo, haciendo una búsqueda sistemática de información, se revisan los principales aspectos clinicopatológicos de las manifestaciones cardiovasculares de la toxocariasis incluyendo su fisiopatología, hallazgos de laboratorio, diagnóstico y opciones terapéuticas, con el objeto de llamar la atención acerca de la importancia de esta zoonosis y su relevancia para la medicina cardiovascular en adultos y en niños.

Toxocariasis is a parasitic infection produced by helminths that cannot reach their adult stage in humans. For their etiological species (Toxocara canis and Toxocara cati), man is a paratenic host. Infection by such helminths can produce a variety of clinical manifestations, such as: visceral larvae migrans syndrome, ocular larvae migrans syndrome and covert toxoca-riasis. In the visceral larvae migrans syndrome, the organs that are mainly involved include liver, lungs, skin, nervous system, muscles, kidneys and the heart. Regarding the latter, the importance of cardiovascular manifestations in toxocariasis, as well as its clinical relevance, has increasingly begun to be recognized. The current article is based on a systematic information search, focused mainly on the clinical and pathological aspects of cardiovascular manifestations in toxocariasis, including its pathophysiology, laboratory findings, diagnosis and therapeutical options, with the objective of highlighting its importance as a zoonosis and its relevance to the fields of cardiovascular medicine in adults and children.

[Cardiovascular manifestations of human toxocariasis]. / Manifestaciones cardiovasculares de la toxocariasis humana.

Toxocariasis is a parasitic infection produced by helminths that cannot reach their adult stage in humans. For their etiological species (Toxocara canis and Toxocara cati), man is a paratenic host. Infection by such helminths can produce a variety of clinical manifestations, such as: visceral larvae migrans syndrome, ocular larvae migrans syndrome and covert toxocariasis. In the visceral larvae migrans syndrome, the organs that are mainly involved include liver, lungs, skin, nervous system, muscles, kidneys and the heart. Regarding the latter, the importance of cardiovascular manifestations in toxocariasis, as well as its clinical relevance, has increasingly begun to be recognized. The current article is based on a systematic information search, focused mainly on the clinical and pathological aspects of cardiovascular manifestations in toxocariasis, including its pathophysiology, laboratory findings, diagnosis and therapeutical options, with the objective of highlighting its importance as a zoonosis and its relevance to the fields of cardiovascular medicine in adults and children.

Behavioral changes in Rattus norvegicus coinfected by Toxocara canis and Toxoplasma gondii.

Using an elevated plus maze apparatus and an activity cage, behavioral changes in Rattus norvegicus concomitantly infected by Toxocara canis and Toxoplasma gondii were studied, during a period of 120 days. Rats infected by Toxocara canis or Toxoplasma gondii showed significant behavioral changes; however, in the group coinfected by both parasites a behavioral pattern similar to that found in the group not infected was observed thirty days after infection, suggesting the occurrence of modulation in the behavioral response.

The significance of cerebral toxocariasis: a model system for exploring the link between brain involvement, behaviour and the immune response.

Toxocara canis is a parasitic nematode that infects canines worldwide, and as a consequence of the widespread environmental dissemination of its ova in host faeces, other abnormal hosts including mice and humans are exposed to infection. In such abnormal or paratenic hosts, the immature third-stage larvae undergo a somatic migration through the organs of the body but fail to reach maturity as adult worms in the intestine. The presence of the migrating larvae contributes to pathology that is dependent upon the intensity of infection and the location of the larvae. A phenomenon of potential public health significance in humans and of ecological significance in mice is that T. canis larvae exhibit neurotrophic behaviour, which results in a greater concentration of parasites in the brain, as infection progresses. Toxocara larval burdens vary between individual outbred mice receiving the same inocula, suggesting a role for immunity in the establishment of cerebral infection. Although the systemic immune response to T. canis has been widely reported, the immune response in the brain has received little attention. Differential cytokine expression and other brain injury-associated biomarkers have been observed in infected versus uninfected outbred and inbred mice. Preliminary data have also suggested a possible link between significant memory impairment and cytokine production associated with T. canis infection. Mice provide a useful, replicable animal model with significant applicability and ease of manipulation. Understanding the cerebral host-parasite relationship may shed some light on the cryptic symptoms of human infection where patients often present with other CNS disorders such as epilepsy and mental retardation.

Transmission of Toxocara canis via ingestion of raw cow liver: a cross-sectional study in healthy adults.

The aim of this study is to ascertain the relationship between ingestion of raw cow liver and Toxocara canis infection. A total of 150 apparently healthy adults were divided into 2 groups; 1 group consisted of 86 adults with positive results of Toxocara ELISA, and the other group of 64 adults with negative results. One researcher collected the history of ingestion of raw cow liver within 1 year and recent history of keeping dogs. Among 86 seropositive adults for T. canis, 68 (79.1%) had a recent history of ingestion of raw cow liver. Multivariate statistical analysis showed that a recent ingestion of raw cow liver and keeping dogs were related to an increased risk of toxocariasis (odds ratios, 4.4 and 3.7; and 95% confidence intervals, 1.9-10.2 and 1.2-11.6, respectively). A recent history of ingestion of raw cow liver and keeping dogs was significantly associated with toxocariasis.

Surgical treatment of ocular toxocariasis: anatomic and functional results in 45 patients.

PURPOSE: To evaluate the anatomic and functional outcome after surgery in patients with complicated ocular toxocariasis. METHODS: A retrospective review of the medical records of pediatric patients who underwent a surgical procedure for ocular toxocariasis from July 1990 to January 2005. Patients with postoperative follow-up shorter than 6 months were excluded from the study. Best-corrected visual acuity (BCVA) was arbitrarily divided into 5 groups: 1) no light perception (NLP); 2) light perception (LP) and hand motion (HM); 3) finger counting (FC) to 20/400; 4) 20/300 to 20/60; and 5) 20/50 to 20/20. RESULTS: Forty-five patients with a mean age of 8.1 years (range 6-10) were included in the study. The ocular toxocariasis presentation most commonly encountered was peripheral granuloma (38%). Twenty-one eyes presented with BCVA in the LP/HM group, 18 (40%) eyes in the FC to 20/400 group, 5 (12%) eyes in the 20/300 to 20/60 group, and 1 (5%) eye in the 20/50 to 20/20 group. The most common surgical procedure was pars plana vitrectomy (PPV) in 58% of the eyes. Four eyes (9%) presented with postoperative BCVA of NLP, 2 eyes (4%) in the LP/HM group, 12 eyes (27%) in the FC to 20/400 group, 19 eyes (42%) in the 20/300 to 20/60 group, and 8 eyes (18%) in the 20/50 to 20/20 group. CONCLUSIONS: Surgical treatment of severe ocular complications secondary to toxocara infections results in satisfactory anatomic results and may improve the overall visual outcome of these patients.

Behavioral changes in Rattus norvegicus experimentally infected by Toxocara canis larvae.

Toxocara canis is a common canine nematode parasite and one of its possible transmission mechanisms is the predation of infected rodents by canids. Fifty Rattus norvegicus were used to study behavioral alterations in rodents infected by T. canis larvae. The rats were divided into three groups: G1, 20 rats infected with 300 T. canis eggs; G2, 20 rats infected with 2,000 T. canis eggs; and G3, 10 non-infected rats. Thirty and 60 days post-infection, rats from all the groups were submitted to an open-field apparatus for five min and subsequently, to an elevated plus-maze apparatus, again for five min. The data obtained indicated improvement in mobility (total locomotion time and rearing frequency) and exploratory behavior in infected rats, principally in G2, which provides some support for the hypothesis that behavioral alterations in rodents infected by Toxocara canis larvae enhance the transmission rate of this ascarid to dogs.

Behavioral changes in Rattus norvegicus experimentally infected by Toxocara canis larvae / Alterações de comportamento em Rattus norvegicus experimentalmente infectados por larvas de Toxocara canis

Toxocara canis is a common canine nematode parasite and one of its possible transmission mechanisms is the predation of infected rodents by canids. Fifty Rattus norvegicus were used to study behavioral alterations in rodents infected by T. canis larvae. The rats were divided into three groups: G1, 20 rats infected with 300 T. canis eggs; G2, 20 rats infected with 2,000 T. canis eggs; and G3, 10 non-infected rats. Thirty and 60 days post-infection, rats from all the groups were submitted to an open-field apparatus for five min and subsequently, to an elevated plus-maze apparatus, again for five min. The data obtained indicated improvement in mobility (total locomotion time and rearing frequency) and exploratory behavior in infected rats, principally in G2, which provides some support for the hypothesis that behavioral alterations in rodents infected by Toxocara canis larvae enhance the transmission rate of this ascarid to dogs.

Toxocara canis é um nematódeo parasita habitual do intestino delgado de cães. Um dos mecanismos conhecidos de transmissão para cães é representado pela predação de pequenos roedores que, como hospedeiros paratênicos albergam larvas de Toxocara canis em seus tecidos. Para avaliar a ocorrência de alterações de comportamento em roedores infectados por Toxocara canis 50 exemplares de Rattus norvegicus foram utilizados no experimento. Os animais foram divididos em três grupos: G1 - 20 ratos infectados com 300 ovos de Toxocara canis; G2 - 20 ratos infectados com 2.000 ovos de Toxocara canis e G3 - 10 ratos sem infecção. Trinta e 60 dias após a infecção avaliou-se a ocorrência de alterações comportamentais nos três grupos submetendo os animais, primeiramente, a uma arena de campo aberto durante cinco minutos e, a seguir, a labirinto em cruz elevado por mais cinco minutos. Os resultados obtidos indicaram aumento significativo da mobilidade (tempo total de movimentação e número de vezes em que os animais se levantaram nas patas traseiras) e comportamento exploratório nos ratos infectados, principalmente nos pertencentes ao G2, sugerindo a ocorrência de alterações comportamentais que favoreceriam a transmissão de Toxocara canis para canídeos por meio de relação presa-predador.

The increase in seroprevalence to Toxocara canis in asthmatic children is related to cross-reaction with Ascaris suum antigens.

BACKGROUND: It has been suggested that the presence of Toxocara canis larvae in lungs is an underlying factor in the onset of asthma. Although the association of asthma and seropositivity to Toxocara has been observed, there are no studies that indicate whether these antibodies are specific against T. canis antigens. METHODS: Seroprevalence to T. canis excretion-secretion antigens (TcES Ag) were compared between asthmatic children (n=285) and non-asthmatic children (n=152), using IgG-ELISA and IgE-ELISA. The recognition patterns of TcES Ag were determined using Western blot (WB). RESULTS: IgG-ELISA seroprevalence was 30.8% for asthmatic children and 19.7% for non-asthmatic children (p<0.05). IgE-ELISA seroprevalence was 7.7% for asthmatic children and 6.5% for non-asthmatic children, respectively (p>0.05). Sera of both groups positive to IgG-ELISA recognised 11 TcES Ag bands for IgG. No differences between the groups were observed regarding recognition patterns; the asthmatic group, however, presented significantly higher cross-reaction to Ascaris suum somatic antigens (AsS Ag) than the non-asthmatic group. Sixty-three sera from asthmatic children positive to IgG-ELISA were evaluated by WB for IgE and 58.7% revealed a recognition pattern for IgE. In the group of non-asthmatic children positive to IgG-ELISA, 80% presented IgE band recognition. No differences were observed between the groups regarding recognition patterns. CONCLUSIONS: The results observed suggest that differences in seroprevalence determined by IgG-ELISA between groups of asthmatic and non-asthmatic children reported by other authors occur because of a higher frequency of cross-reaction in asthmatic children.

[Tropical causes of epilepsy]. / Causas tropicales de epilepsia.

INTRODUCTION: Eighty-five percent of all epileptics live in tropical regions. Prenatal risk factors, traumatic brain injuries and different parasitic infestations of the central nervous system (CNS) are the reasons behind the high prevalence of epilepsy. This work reviews the main parasitic infestations causing epilepsy in the tropics. DEVELOPMENT: Neurocysticercosis is the main cause of focal epilepsy in early adulthood in endemic areas (30-50%). All the phases of cysticerci (viable, transitional and calcified) are associated with epileptic seizures. Anti-cysticercus treatment helps get rid of cysticerci faster and reduces the risk of recurrence of seizures in patients with viable cysts. Symptomatic epilepsy can be the first manifestation of neuroschistosomiasis in patients without any systemic symptoms. The pseudotumoral form can trigger seizures secondary to the presence of granulomas and oedemas in the cerebral cortex. The eggs of Schistosoma japonicum are smaller, reach the CNS more easily and trigger epileptic seizures more frequently. Toxocariasis and sparganosis are other parasitic infestations that can give rise to symptomatic seizures. The risk factors for suffering chronic epilepsy after cerebral malaria are a positive familial history of epilepsy and a history of episodes of fever and cerebral malaria that began with coma or which progressed with multiple, prolonged epileptic seizures. About 20% of patients with cerebral infarction secondary to Chagas disease present late vascular epilepsy as a complication. CONCLUSIONS: Very few studies have been conducted to examine the prognosis, risk of recurrence and modification of the natural course of seizures associated with tropical parasitic infestations, except for the case of neurocysticercosis.