Taenia solium: Socioeconomic changes and prevalence evolution in four endemic communities in northwestern Mexico.

In Mexico, for the past 30 years, a continuous decrease in the incidence of clinical taeniosis/cysticercosis has been documented. This work aimed to determine the influence of improvement in socioeconomic conditions on the prevalence of Taenia solium in four endemic communities in northwestern Mexico. This study was carried out in two phases. First, documentary information (1989-2018) was collected about the prevalence of Theridion solium in the federal entity of Sinaloa State. Second, a pilot study was performed in four communities of Sinaloa, which had an endemic history of Taenia transmission. In each community, a risk factor questionnaire was applied, and serum and stool samples were collected for convenience in a non-probabilistic way. Anti-cysticercus antibodies and adult worm coproantigen were determined. The documentary analysis showed the incidence of taeniosis and cysticercosis to have decreased by 98 and 53%, respectively, while the human development index increased by 5% (1992-2017). Our data suggest that the risk of parasitic transmission is low, although female sex was a risk factor for reporting tremors or seizures (prevalence rate 2.1336, CI: 1.1821-3.8508) and background of tapeworm infection (prevalence rate 1.2893, CI: 0.9795-1.6972). No tapeworms or eggs were found while examining stool samples, but protozoa cysts were observed in four samples. Unexpectedly, only one of the 79 stool samples was positive for coproantigens. This positive result was confirmed in a second sample. However, the evaluation of a third sample was negative. No antibodies were found in human (n = 377) or pig (n = 69) samples. These data suggest parasite transmission has been interrupted and could be possibly associated with improving socioeconomic conditions. Further studies are needed to determine the real prevalence of zoonoses in Mexico.

Diagnostic value of glycoprotein band patterns of three serologic enzyme-linked immunoelectrotransfer blot assays for neurocysticercosis.

The enzyme-linked immunoelectrotransfer blot (EITB) assay to detect antibodies in serum is a complementary tool for the diagnosis of neurocysticercosis (NCC). Presence of at least one glycoprotein band corresponding to a Taenia solium (T. solium) antigen indicates a positive result; however, EITB assays have multiple glycoprotein bands, and previous work has suggested that band patterns may have additional diagnostic value. We included 58 participants with a definitive diagnosis of NCC who received care at the Instituto Nacional de Neurología y Neurocirugía in Mexico City. Three different EITB tests were applied to participants' serum samples (LDBio, France; US Centers for Disease Control and Prevention [CDC]; and Instituto de Diagnóstico y Referencia Epidemiológicos [InDRE]). There was substantial variability in specific glycoprotein band patterns among the three assays. However, in age- and sex-adjusted logistic regression models, the number of glycoprotein bands was positively associated with the presence of vesicular extraparenchymal cysts (InDRE adjusted odds ratio [aOR] 1.60 p < 0.001; CDC aOR 6.31 p < 0.001; LDBio aOR 2.45 p < 0.001) and negatively associated with the presence of calcified parenchymal cysts (InDRE aOR 0.63 p < 0.001; CDC aOR 0.25 p < 0.001; LDBio aOR 0.44 p < 0.001). In a sensitivity analysis also adjusting for cyst count, results were similar. In all three EITB serum antibody tests, the number of glycoprotein bands consistently predicted cyst stage and location, although magnitude of effect differed.

Statistical approach to Trichinella infection in horses handled by rural slaughterhouses across five distinctive socioeconomic regions in Mexico.

This work aimed to investigate the prevalence of Trichinella infection in horses (Equus ferus caballus) handled by rural slaughterhouses across five distinctive socioeconomic regions in Mexico. Serum samples were obtained by non-probabilistic convenience sampling in the Eastern, Southern Central and Western regions (100 samples of each). Additionally, muscle tissue samples were collected from the East (n=45), Southeastern (n=88), Southern Central (n=39) and Southwestern (n=11) regions. Antibodies were determined by Western blot and the muscle tissue was examined by artificial digestion. A global antibody prevalence of 2% was obtained. Regionally, a prevalence of 5% was observed in the East and 1% in the Southern Central region. No antibodies were detected in the West region and no larvae were found in the muscle tissue samples. These findings support the low presence of Trichinella in Mexican horses, which can positively impact the Mexican horse meat trade.

Immunodiagnosis of human neurocysticercosis: comparative performance of serum diagnostic tests in Mexico.

Immunodiagnosis has a supportive role in the diagnosis of neurocysticercosis (NCC). The aim of this study was to compare the validity of seven immunodiagnostic tests among serum samples from 58 patients with NCC, 26 patients with neurological diseases other than NCC, and 15 healthy controls. One test for viable parasite detection (HP10 antigen assay) and six for antibody detection were evaluated. For the entire sample, sensitivities ranged from 55.2% (NOVALISA) to 81.0% (enzyme-linked immunosorbent assay [ELISA] Taenia solium antibody), with the sensitivity of the latter test significantly higher than that of the in-house ELISA Taenia crassiceps, NOVALISA, enzyme-linked immunoelectrotransfer blot (EITB) CDC, and HP10. Overall, specificities were high, ranging from 85.4% (ELISA Ts) to 97.1% (NOVALISA), with no statistically significant differences. Detection of HP10 antigen was significantly associated with the presence of vesicular parasites. The simple and low-cost ELISA Taenia solium antibody Ab instead of EITB is recommended to support NCC diagnosis in both rural and hospital settings in Mexico.

Comparison of DOT-ELISA and Standard-ELISA for Detection of the Vibrio cholerae Toxin in Culture Supernatants of Bacteria Isolated from Human and Environmental Samples.

A comparison of DOT-ELISA and Standard-ELISA was made for detection of Vibrio cholerae toxin in culture supernatants of bacteria isolated from human and environmental samples. A total of 293 supernatants were tested in a double blind assay. A correlation of 100 % was obtained between both techniques. The cholera toxin was found in 20 Inaba and 3 Ogawa strains. Positive samples were from seafood (17 samples), potable water (1 sample) and sewage (5 samples). The DOT-ELISA was useful as the standard-ELISA to confirm the presence of cholera toxin in the environmental samples.

Successful capture of Toxocara canis larva antigens from human serum samples.

BACKGROUND: Toxocara canis is a nematode that parasitizes dogs, while humans are paratenic hosts. When humans are infected the migrating larvae damage the liver, lungs and even the nervous system. Larva migrans diagnosis is based on immunological techniques; however, the commercial immunodiagnostic kits detect anti-T. canis antibodies which may cross-react with other parasites, mainly nematodes with extra-intestinal migration. Moreover, antibodies do not necessarily reflect an active infection; so detection and quantification of circulating antigens may provide appropriate and timely information for treatment, which prevents irreversible damage. Here we report the standardization of a monoclonal antibody based antigen capture ELISA to diagnose human toxocariasis without cross-reaction. METHODS: We developed anti-T. canis polyclonal antibodies in rabbits and a monoclonal antibody in mouse which did not cross-react with 15 antigens from several parasites. The sandwich ELISA standardization was performed using sera from mice experimentally infected. We tested the method using 29 positive and 58 negative human sera previously typified with a commercial kit, which detects antibodies. RESULTS: Only 5.0 µg/mL and 10 µg/mL polyclonal antibodies and monoclonal antibody, respectively, were needed in the sandwich ELISA standardization, detecting since 440 pg/mL larva antigens. Nine out of 29 antibody-positive sera were also positive for antigens and no false positive were found. Taking the antibody kit as the reference standard, the sensibility and specificity of the antigen test were 31% and 100%, respectively. CONCLUSIONS: With these tools we established a detection threshold as low as 440 pg/mL antigen. Monoclonal antibody is specific, and did not cross-react with antigens from other parasites. Detection of circulating antigens helps provide appropriate and timely treatment and prevents irreversible damage.

[Cysticercosis research in epileptic patients dwelling in towns of the western Cariri in the State of Paraíba, Brazil]. / Estudo da cisticercose em pacientes portadores de epilepsia residentes em municípios do Cariri paraibano.

This research involved a sample of 110 epileptic patients from western Cariri, Paraíba, Brazil and it has been developed in three successive phases. During the first one, an epidemiological form was applied with the aim of identifying risk factors related to the taeniasis cysticercosis complex in the etiology of the patients' epilepsy. The second phase consisted of immunological exams of 110 patients, by means of the EITB technique to identify the anti-cysticerci serum antibodies, whereas the presence of circulating antigens was verified through the ELISA technique. In the third phase, thirteen patients who were seropositive, were submitted to brain CT scan. Applying the questionnaire enabled us to know some risk factors. The seroprevalence detected was 118.2/1000 inhabitants. Out of the 13 seropositive patients for cysticercosis, 46.1% presented parenchymal cysticercotic damage. Based on these results, we are able to conclude that the studied towns reveal an epidemiological profile which is compatible with the occurrence of the taeniasis cysticercosis complex and cysticercosis plays an important role in the sprouting of epilepsy in these patients.

Estudo da cisticercose em pacientes portadores de epilepsia residentes em municípios do Cariri paraibano / Cysticercosis research in epileptic patients dwelling in towns of the western Cariri in the State of Paraíba, Brazil

Este estudo contou com uma amostra de 110 pacientes epilépticos residentes no Cariri paraibano, tendo sido desenvolvido em três etapas sucessivas. Durante a primeira etapa, aplicou-se a ficha epidemiológica visando identificar fatores de risco associados ao complexo teníase-cisticercose na etiologia da epilepsia dos pacientes. A segunda etapa consistiu em exames imunológicos dos 110 pacientes com a utilização da técnica EITB para a identificação de anticorpos séricos anti-cisticercos, e da técnica ELISA para a presença de antígenos circulantes. Na terceira etapa, treze pacientes com sorologia considerada positiva foram submetidos a exames tomográficos. A partir da aplicação do questionário, foram detectados alguns fatores de risco. A soroprevalência constatada foi 118,2/1000 habitantes. Dos 13 pacientes com sorologia positiva para cisticercose, 46,1 por cento têm lesões sugestivas de cisticercose de localização parenquimatosa. Conclui-se que os municípios estudados apresentam perfil epidemiológico compatível com a ocorrência do complexo teníase-cisticercose e que a cisticercose possivelmente desempenhe papel importante no surgimento da epilepsia nesses pacientes.

Short report: limited and short-lasting humoral response in Taenia solium: seropositive households compared with patients with neurocysticercosis.

Epidemiologic data suggest that 30-40% of Taenia solium-seropositive people become spontaneously negative without acquiring cysticercosis. To compare the responses of these individuals with those of patients with neurocysticercosis, we screened seropositive persons among family members of 16 patients. We searched for specific antibodies in patients and their 118 households by an enzyme-linked immunoelectrotransfer blot assay using specific glycoproteins of T. solium metacestodes. We found six seropositive individuals without neurocysticercosis among members of four families. The matching patients were young, harbored viable cysts, and had short evolution of disease. The baseline response of healthy seropositive individuals was scarce and showed a low frequency of antibodies against glycoproteins GP39-42 and GP24, which are immunodominant in patients with neurocysticercosis. Moreover, they became spontaneously negative in few months. The response of patients was heterogeneous as shown in other studies. The results of this work support a highly dynamic host-parasite immunologic interaction and suggest individual susceptibility or level of exposure among family members.

Evaluation of the enzyme-linked immunoelectrotransfer blot assay for diagnosis of neurocysticercosis in children.

Neurocysticercosis is a common problem in developing countries, and it causes neurologic disorders in children. Immunodiagnosis with Taenia solium glycoproteins as an antigen has been validated in adults but not in children. The aim of this work was to evaluate a Taenia solium glycoproteins-based enzyme-linked immunoelectrotransfer blot assay in children with neurocysticercosis. Twenty-five confirmed cases of neurocysticercosis and 50 healthy children from the same community were included. The test had a sensitivity of 72% and a specificity of 96%. Sensitivity was higher (100%) in cases with multiple cysts and in multiple sites. Sensitivity was higher when cysts were in parenchyma (86%) than when they were in the subarachnoid space. The most frequently recognized proteins were 24, 39 to 42, and 50 kDa. Diagnosis was more efficient in serum than in cerebrospinal fluid. Western blot is a reliable method for serologic diagnosis of neurocysticercosis in children. Multiple cysts and infections in multiple sites elicited a stronger immune response.

Taeniasis and cysticercosis prevalence in a small village from Northeastern Brazil.

UNLABELLED: Although not considered as an endemic region, the Northeast of Brazil has the necessary conditions for the development of taeniasis-cysticercosis complex. In a previous paper, we demonstrated that Mulungu do Morro municipality, in the State of Bahia, has a high seroprevalence to cysticercosis in epileptic patients. OBJECTIVE: to determine the prevalence of taeniasis and positive cysticercosis serology in the population of Mulungu do Morro. METHOD: blood and stool samples were collected from a random sampling of the population, by family. The identification of antibodies against T. solium cysticerci was made by EITB and T. solium antigens were identified using a polyclonal antibody-capture ELISA. RESULTS: the cysticercosis seroprevalence was 1.6% (C.I. = 0.8 to 2.8%) and the taeniasis prevalence 4.5% (C.I. = 3.0 to 6.5%). Seropositivity to cysticercosis was higher among those who lived in a house of a person testing positive for coproantigen, p=0.017. CONCLUSION: our results demonstrate that the taeniasis-cysticercosis complex is endemic in Mulungu do Morro. We believe that all areas in the world with the same socio-economic and sanitary characteristics are likely to have high prevalence of this parasite.

Taeniasis and cysticercosis prevalence in a small village from Northeastern Brazil

Although not considered as an endemic region, the Northeast of Brazil has the necessary conditions for the development of taeniasis-cysticercosis complex. In a previous paper, we demonstrated that Mulungu do Morro municipality, in the State of Bahia, has a high seroprevalence to cysticercosis in epileptic patients. OBJECTIVE: to determine the prevalence of taeniasis and positive cysticercosis serology in the population of Mulungu do Morro. METHOD: blood and stool samples were collected from a random sampling of the population, by family. The identification of antibodies against T. solium cysticerci was made by EITB and T. solium antigens were identified using a polyclonal antibody-capture ELISA. RESULTS: the cysticercosis seroprevalence was 1.6 percent (C.I. = 0.8 to 2.8 percent) and the taeniasis prevalence 4.5 percent (C.I. = 3.0 to 6.5 percent). Seropositivity to cysticercosis was higher among those who lived in a house of a person testing positive for coproantigen, p=0.017. CONCLUSION: our results demonstrate that the taeniasis-cysticercosis complex is endemic in Mulungu do Morro. We believe that all areas in the world with the same socio-economic and sanitary characteristics are likely to have high prevalence of this parasite

Laboratory diagnosis of human neurocysticercosis: double-blind comparison of enzyme-linked immunosorbent assay and electroimmunotransfer blot assay.

Neurocysticercosis is a common disease in underdeveloped countries. Its diagnosis is based on clinical, imaging (tomography or magnetic resonance), epidemiological, and laboratory data. Several methods based on the detection of antibodies against cysticerci in cerebrospinal fluid or serum have been tested. Among them, an enzyme-linked immunosorbent assay (ELISA) based on the use of a crude parasite antigen has been used by the laboratory network of cysticercosis in Mexico, which has given support to clinicians for up to 7 years. A Taenia solium-specific glycoprotein-based electroimmunotransfer blot (EITB) assay was reported to be highly sensitive and specific for this purpose. In order to compare both techniques, we studied 100 neurocysticercosis patients and 70 neurological noncysticercosis controls and searched for specific antibodies in paired samples of serum and cerebrospinal fluid using both techniques. We found that the EITB assay is more sensitive than the ELISA, especially when serum is being tested. Both techniques are more sensitive in cases with multiple living cysts than in cases with single cysts or calcified lesions. No global differences among cases with parasites located in different parts of the central nervous system were found. In the patients with cysts within the parenchyma, the sensitivity of the EITB assay was higher with serum than with cerebrospinal fluid. The immunodominant bands were found to be the same as those previously reported, i.e., GP-39 to -42, GP-24, and GP-13. Based on these results, we suggest the use of the EITB assay in routine diagnosis of cysticercosis for clinical cases.

Cysticercosis in epileptic patients of Mulungu do Morro Northeastern Brazil

With the aim to study the magnitude of infection by the metacestode of Taenia solium in a population of epileptic patients in the arid region of Bahia, Northeastern Brazil, we examined 200 consecutive cases who attended an ambulatory clinic in the disctrict of Mulungu do Morro. Sixty-six of the patients had a diagnosis of epilepsy. From them 10 (15.2 percent) presented antibodies against a specific fraction of antigens in Western blot, and 4 (6.0 percent) had circulating parasite products, as tested by capture ELISA. Only 1 case was positive for antibodies and antigens. We found that the frequency of seropositivity was related to the time without epileptic seizure. We conclude that cysticercosis is endemic in the region of Mulungu do Morro and that it is related to a benign form of epilepsy

Teniasis y cisticercosis por Taenia solium / Taeniasis and cysticercosis by Taenia solium

Obras descriptivas que muestran los requisitos a seguir para el análisis y estudio de los problemas de salud en México a nivel epidemiológico. En este caso, el cuaderno del Instituto Nacional de Diagnóstico y Referencia Epidemiológicos se dedicó a detallar las normas necesarias para llevar a cabo el análisis microbiológico de la teniasis y cisticercosis. El libro se divide en siete capítulos: 1. Introducción 2. Sobre el parásito 3. Sobre el huésped 4. Sobre la enfermedad 5. Sobre la epidemiología 6. Sobre la inmunología 7. Referencias