Hector H Garcia

Universidad Peruana Cayetano Heredia, Λίμα, Provincia de Lima, Peru

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Publications (241)1190.81 Total impact

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    ABSTRACT: Calcified neurocysticercosis has been associated with hippocampal atrophy in patients with refractory epilepsy, but the relevance of this association in the population at large is unknown. We assessed calcified cysticerci and its association with hippocampal atrophy in elderly persons living in Atahualpa, an Ecuadorian village endemic for neurocysticercosis. All Atahualpa residents ≥ 60 years of age were invited to undergo computed tomography/magnetic resonance imaging for neurocysticercosis detection. Twenty-eight (11%) out of 248 enrolled persons had calcified cysticerci (case-patients) and were matched 1:1 by age, sex, and years of education to individuals without neurocysticercosis on computed tomography/magnetic resonance imaging (controls). Four case-patients and none of the controls had epilepsy (P = 0.134). Cognitive performance was similar across both groups. The Scheltens' medial temporal atrophy scale was used for hippocampal rating in case-patients and matched controls without neurocysticercosis. Mean score in the Scheltens' scale was higher in case-patients than in controls (p < 0.001). Atrophic hippocampi were noticed in 19 case-patients and five controls (P = 0.003). Atrophy was bilateral in 11 case-patients and unilateral in eight. All case-patients with unilateral hippocampal atrophy had at least one ipsilateral calcification. This study shows an association between calcified cysticerci and hippocampal atrophy and raises the possibility of an inflammation-mediated hippocampal damage as the responsible mechanism for these findings.
    The American journal of tropical medicine and hygiene 10/2014; · 2.53 Impact Factor
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    ABSTRACT: Taenia solium infection causes severe neurological disease in humans. Even though infection and exposure to swine cysticercosis is scattered throughout endemic villages, location of the tapeworm only explains some of the nearby infections and is not related to location of seropositive pigs. Other players might be involved in cysticercosis transmission. In this study we hypothesize that pigs that carry nematodes specific to dung beetles are associated with cysticercosis infection and/or exposure. We carried out a cross-sectional study of six villages in an endemic region in northern Peru. We euthanized all pigs (326) in the villages and performed necropsies to diagnose cysticercosis. For each pig, we counted cysticerci; measured anti-cysticercus antibodies; identified intestinal nematodes; tabulated distance to nearest human tapeworm infection; and recorded age, sex, productive stage, and geographic reference. For the purpose of this paper, we defined cysticercosis infection as the presence of at least one cysticercus in pig muscles, and cysticercosis exposure as seropositivity to anti-cysticercus antibodies with the presence of 0-5 cysticerci. Compared to pigs without nematode infections, those pigs infected with the nematode Ascarops strongylina were significantly associated with the presence of cysticerci (OR: 4.30, 95%CI: 1.83-10.09). Similarly, pigs infected with the nematode Physocephalus sexalatus were more likely to have cysticercosis exposure (OR: 2.21, 95%CI: 1.50-3.28). In conclusion, our results suggest that there appears to be a strong positive association between the presence of nematodes and both cysticercosis infection and exposure in pigs. The role of dung beetles in cysticercosis dynamics should be further investigated.
    PLoS neglected tropical diseases. 10/2014; 8(10):e3247.
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    ABSTRACT: Taenia solium is a major cause of preventable epilepsy in developing nations. Screening and treatment of human intestinal stage infection (taeniasis) within high-risk foci may reduce transmission and prevent epilepsy by limiting human exposure to infective eggs. We piloted a ring-strategy that involves screening and treatment for taeniasis among households located nearby pigs heavily-infected with the larval stage (cysticercosis). These pigs mark areas of increased transmission and can be identified by tongue examination.
    PLoS Neglected Tropical Diseases 09/2014; 8(9):e3125. · 4.57 Impact Factor
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    ABSTRACT: Objective Neurocysticercosis (NCC) is a major cause of seizures and epilepsy in endemic countries. Antiparasitic treatment of brain cysts leads to seizures due to the host's inflammatory reaction, requiring concomitant steroids. We hypothesized that increased steroid dosing will reduce treatment-associated seizures.Methods Open-label randomized trial comparing 6 mg/day dexamethasone for 10 days (conventional) with 8 mg/day for 28 days followed by a 2-week taper (enhanced) in patients with NCC receiving albendazole. Follow-up included active seizure surveillance and brain imaging. Study outcomes were seizure days and patients with seizures, both measured in days 11–42. Additional analyses compared days 1–10, 11–21, 22–32, 33–42, 43–60, and 61–180.ResultsThirty-two individuals were randomized into each study arm; two did not complete follow-up. From days 11 to 42, 59 partial and 6 generalized seizure days occurred in 20 individuals, nonsignificantly fewer in the enhanced arm (12 vs. 49, p = 0.114). The numbers of patients with seizures in this period showed similar nonsignificant differences. In the enhanced steroid arm there were significantly fewer days and individuals with seizures during antiparasitic treatment (days 1–10: 4 vs. 17, p = 0.004, and 1 vs. 10, p = 0.003, number needed to treat [NNT] 4.6, relative risk [RR] 0.1013, 95% confidence interval [CI] 0.01–0.74) and early after dexamethasone cessation (days 11–21: 6 vs. 27, p = 0.014, and 4 vs. 12, p = 0.021, NNT 4.0, RR 0.33, 95% CI 0.12–0.92) but not after day 21. There were no significant differences in antiparasitic efficacy or relevant adverse events.SignificanceIncreased dexamethasone dosing results in fewer seizures for the first 21 days during and early after antiparasitic treatment for viable parenchymal NCC but not during the first 11–42 days, which was the primary predetermined time of analysis.
    Epilepsia 07/2014; · 3.96 Impact Factor
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    ABSTRACT: Cysticidal drug treatment of viable Taenia solium brain parenchymal cysts leads to an acute pericystic host inflammatory response and blood brain barrier breakdown (BBB), commonly resulting in seizures. Naturally infected pigs, untreated or treated one time with praziquantel were sacrificed at 48 hr and 120 hr following the injection of Evans blue (EB) to assess the effect of treatment on larval parasites and surrounding tissue. Examination of harvested non encapsulated muscle cysts unexpectedly revealed one or more small, focal round region(s) of Evans blue dye infiltration (REBI) on the surface of otherwise non dye-stained muscle cysts. Histopathological analysis of REBI revealed focal areas of eosinophil-rich inflammatory infiltrates that migrated from the capsule into the tegument and internal structures of the parasite. In addition some encapsulated brain cysts, in which the presence of REBI could not be directly assessed, showed histopathology identical to that of the REBI. Muscle cysts with REBI were more frequent in pigs that had received praziquantel (6.6% of 3736 cysts; n = 6 pigs) than in those that were untreated (0.2% of 3172 cysts; n = 2 pigs). Similar results were found in the brain, where 20.7% of 29 cysts showed histopathology identical to muscle REBI cysts in praziquantel-treated pigs compared to the 4.3% of 47 cysts in untreated pigs. Closer examination of REBI infiltrates showed that EB was taken up only by eosinophils, a major component of the cellular infiltrates, which likely explains persistence of EB in the REBI. REBI likely represent early damaging host responses to T. solium cysts and highlight the focal nature of this initial host response and the importance of eosinophils at sites of host-parasite interaction. These findings suggest new avenues for immunomodulation to reduce inflammatory side effects of anthelmintic therapy
    PLoS ONE 06/2014; · 3.53 Impact Factor
  • Hector H. Garcia, Silvia Rodriguez, Jon S. Friedland
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    ABSTRACT: The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools containing T. solium eggs and develop cysticercosis, and humans ingest pork infected with cystic larvae and develop intestinal taeniasis, or may also accidentally acquire cysticercosis by fecal-oral contamination. Cysticercosis of the human nervous system, neurocysticercosis, is a major cause of seizures and other neurological morbidity in most of the world. The dynamics of exposure, infection and disease as well as the location of parasites result in a complex interaction which involves immune evasion mechanisms and involutive or progressive disease along time. Moreover, existing data is limited by the relative lack of animal models. This manuscript manuscript revises the available information on the immunology of human taeniasis and cysticercosis.This article is protected by copyright. All rights reserved.
    Parasite Immunology 06/2014; · 2.21 Impact Factor
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    ABSTRACT: Human cysticercosis is a zoonotic disease causing severe health disorders and even death. While prevalence data become available worldwide, incidence rate and cumulative incidence figures are lacking, which limits the understanding of the Taenia solium epidemiology.
    PLoS Neglected Tropical Diseases 05/2014; 8(5):e2887. · 4.57 Impact Factor
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    ABSTRACT: The present study evaluated the capacity of Ammophorus rubripes beetles to carry Taenia solium eggs, in terms of duration and viability of eggs in their digestive system. One hundred beetles were distributed into five polyethylene boxes, and then they were infected with T. solium eggs. Gravid proglottids of T. solium were crushed and then mixed with cattle feces. One gram of this mixture was placed in each box for 24 hours, after which each group of beetles was transferred into a new clean box. Then, five beetles were dissected every three days. Time was strongly associated with viability (r=0.89; P<0.001) and the calculated time to cero viability is 36 days. The eggs in the intestinal system of each beetle were counted and tested for viability. Taenia solium eggs were present in the beetle's digestive system for up to 39 days (13th sampling day out of 20), gradually reducing in numbers and viability, which was 0 on day 36 post-infection. Egg viability was around 40% up to day 24 post-infection, with a median number of eggs of 11 per beetle at this time. Dung beetles may potentially contribute towards dispersing T. solium eggs in endemic areas.
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology: Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 03/2014; 23(1):94-7. · 0.72 Impact Factor
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    ABSTRACT: One of the best characterized tests for diagnosis of neurocysticercosis (NCC) is the enzyme-linked immunoelectrotransfer blot (EITB) developed at CDC that uses lentil-lectin purified glycoproteins (LLGP) extracted from T. solium cysticerci. Although the test is very reliable, purification of the LLGP antigens has been difficult to transfer to other laboratories because of the need for expensive equipment and technical expertise. To develop a simpler assay, we have previously purified and cloned the diagnostic glycoproteins in the LLGP fraction. In this study, we evaluated three representative recombinant or synthetic antigens from the LLGP fraction, individually and in different combinations, using an immunoblot assay (recombinant EITB). Using a panel of 249 confirmed-positive and 401 negative sera the sensitivity of the recombinant EITB was determined to be 99% and the specificity 99% for diagnosis of NCC. We also tested an additional panel of 239 confirmed NCC-positive sera in Lima, Peru and found similar results. Overall our data show that the performance characteristics of the recombinant EITB are comparable to the LLGP-EITB assay. This new recombinant/synthetic antigen based assay is sustainable and can be easily transferred to laboratories in the U.S. and throughout the world.
    Journal of clinical microbiology 02/2014; · 4.16 Impact Factor
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    ABSTRACT: The prevalence of epilepsy added to inadequate treatment results in chronic morbidity and considerable mortality in poor populations. Neurocysticercosis (NCC), a helminthic disease of the central nervous system, is a leading cause of seizures and epilepsy in most of the world. Taking advantage of a cysticercosis elimination program, we performed two community-based cross-sectional studies between 2006 and 2007 in 58 rural communities (population 20,610) to assess the prevalence and characteristics of epilepsy and epileptic seizures in this endemic region. Serological and computed tomography (CT) data in individuals with epilepsy were compared to previous surveys in general population from the same region. In two surveys, 17,450 individuals were evaluated. Lifetime prevalence of epilepsy was 17.25/1000, and prevalence of active epilepsy was 10.8/1000 inhabitants. The prevalence of epilepsy increased after age 25 years and dropped after age 45. Only 24% (45/188) of patients with active epilepsy were taking antiepileptic drugs, all at sub-therapeutic doses. Antibodies to cysticercosis were found in approximately 40% of individuals with epilepsy in both studies. In one survey only individuals presenting strong antibody reactions were significantly associated with having epilepsy (OR 5.74; p<0.001). In the second, the seroprevalence as well as the proportion presenting strong antibody reactions were both significantly higher in individuals with epilepsy (OR 2.2 and 4.33, respectively). Brain CT showed NCC-compatible images in 109/282 individuals with epilepsy (39%). All individuals with viable parasites on CT were seropositive. The prevalence of epilepsy in this cysticercosis endemic region is high and NCC is an important contributor to it.
    PLoS Neglected Tropical Diseases 02/2014; 8(2):e2692. · 4.57 Impact Factor
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    ABSTRACT: The Enzyme-linked Immunoelectrotransfer Blot (EITB) has been used widely as a screening test for Taenia solium cysticercosis in swine. However, the relation between seropositivity and infection in pig populations from endemic areas has not been well defined. The aim of this study is to relate EITB seropositivity with infection and infection burden, analyse the trade-off between sensitivity and specificity with various cut-off points for the EITB assay, and finally describe the serology changes in a cohort of rural pigs raised under natural conditions. A group of 107 pigs that were used as controls during a vaccination field trial in Peru was our study population. The prevalence of porcine cysticercosis determined by necropsy examination was 16.82% (18/107) in these animals. Using EITB reactivity to ≥1 band as a cut-off point for the assay, the sensitivity was 88.89% (65.29–98.62, 95% CI) and the specificity was 48.31% (37.59–59.16, 95% CI). Comparing other cut-off points, involving up to as many as 7 reactive bands, a reactivity of ≥3 bands provided the best trade-offs in sensitivity and specificity. Using this cut-off point for the assay, the sensitivity was 77.77% (52.36–93.59, 95% CI) and the specificity was 76.40% (66.22–84.76, 95% CI). A significant association was found between cyst counts over 100 cysts and reactivity to ≥3 bands in the EITB assay (Fisher's exact test, p < 0.05). The results of this study suggest that the use of the EITB assay to study porcine cysticercosis may require setting different cut-offs under field and experimental conditions, and depending upon the objective of the screening process.
    Veterinary Parasitology 01/2014; 199(s 1–2):42–49. · 2.38 Impact Factor
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    ABSTRACT: Background Neurocysticercosis causes a substantial burden of seizure disorders worldwide. Treatment with either praziquantel or albendazole has suboptimum efficacy. We aimed to establish whether combination of these drugs would increase cysticidal efficacy and whether complete cyst resolution results in fewer seizures. We added an increased dose albendazole group to establish a potential effect of increased albendazole concentrations. Methods In this double-blind, placebo-controlled, phase 3 trial, patients with viable intraparenchymal neurocysticercosis were randomly assigned to receive 10 days of combined albendazole (15 mg/kg per day) plus praziquantel (50 mg/kg per day), standard albendazole (15 mg/kg per day), or increased dose albendazole (22·5 mg/kg per day). Randomisation was done with a computer generated schedule balanced within four strata based on number of cysts and concomitant antiepileptic drug. Patients and investigators were masked to group assignment. The primary outcome was complete cyst resolution on 6-month MRI. Enrolment was stopped after interim analysis because of parasiticidal superiority of one treatment group. Analysis excluded patients lost to follow-up before the 6-month MRI. This trial is registered with ClinicalTrials.gov, number NCT00441285. Findings Between March 3, 2010 and Nov 14, 2011, 124 patients were randomly assigned to study groups (41 to receive combined albendazole plus praziquantel [39 analysed], 43 standard albendazole [41 analysed], and 40 increased albendazole [38 analysed]). 25 (64%) of 39 patients in the combined treatment group had complete resolution of brain cysts compared with 15 (37%) of 41 patients in the standard albendazole group (rate ratio [RR] 1·75, 95% CI 1·10–2·79, p=0·014). 20 (53%) of 38 patients in the increased albendazole group had complete cyst resolution at 6-month MRI compared with 15 (37%) of 41 patients in the standard albendazole group (RR 1·44, 95% CI 0·87–2·38, p=0·151). No significant differences in adverse events were reported between treatment groups (18 in combined treatment group, 11 in standard albendazole group, and 19 in increased albendazole group). Interpretation Combination of albendazole plus praziquantel increases the parasiticidal effect in patients with multiple brain cysticercosis cysts without increased side-effects. A more efficacious parasiticidal regime without increased treatment-associated side-effects should improve the treatment and long term prognosis of patients with neurocysticercosis. Funding National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health.
    The Lancet infectious diseases. 01/2014;
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    ABSTRACT: This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that posttranslational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells.
    Parasitology Research 08/2013; · 2.85 Impact Factor
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    ABSTRACT: Background. Computed tomography (CT) remains the standard neuroimaging screening exam for neurocysticercosis, and residual brain calcifications are the commonest finding. Magnetic resonance imaging (MRI) is more sensitive than CT but is rarely available in endemic regions. Enzyme-linked immunolectrotransfer blot (EITB) uses antibody detection for diagnosis confirmation; by contrast, ELISA antigen detection (Ag-ELISA) detects circulating parasite antigen. This study evaluated whether these assays predict undetected viable cysts in patients with only calcified lesions on brain CT. Methods. Serum samples from 39 patients with calcified neurocysticercosis and no viable parasites on CT were processed by Ag-ELISA and EITB. MRI was performed for each patient within two months of serologic testing. Conservatively high ELISA and EITB cut-offs were used to predict the finding of viable brain cysts on MRI. Results. Using ROC-optimized cut offs, seven patients were Ag-ELISA positive, and eight had strong antibody reactions on EITB. MRI showed viable brain cysts in seven (18.0%) patients. Patients with positive Ag-ELISA were more likely to have viable cysts than Ag-ELISA negatives (6/7 versus 1/32, OR 186, 95%CI 1 to 34470.0, p<0.001; sensitivity 85.7%, specificity 96.9%, positive likelihood-ratio of 27 to detect viable cysts). Similar but weaker associations were also found between a strong antibody reaction on EITB and undetected viable brain cysts. Conclusions. Antigen detection, and in a lesser degree strong antibody reactions, can predict viable neurocysticercosis. Serological diagnostic methods could identify viable lesions missed by CT in patients with apparently only calcified cysticercosis and could be considered for diagnosis workup and further therapy.
    Clinical Infectious Diseases 06/2013; · 9.37 Impact Factor
  • Oscar H Del Brutto, Héctor H Garcia
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    ABSTRACT: OBJECTIVE: Review of cases of intramedullary spinal cord cysticercosis diagnosed with MRI to outline the features and outcome of this overlooked form of presentation of neurocysticercosis. METHODS: MEDLINE, LILACS, and manual search of case reports or case series of patients with intramedullary cysticercosis evaluated with MRI. Abstracted data included: demographic profile, clinical manifestations, neuroimaging findings, therapy, and follow-up. RESULTS: Forty-three patients were reviewed. Mean age was 36years, and 65% were men. Most patients (67%) had parasites located at the thoracic spinal cord. All but two patients had a single cyst. The most common form of presentation was a subacute or chronic transverse myelopathy. On MRI, all lesions had signal properties paralleling that of CSF, and most were surrounded by edema and had a "ring-like" pattern of abnormal enhancement. The scolex of the parasite was visualized in 16 (37%) cases. Twenty-nine patients underwent surgical resection of the lesion, and 14 were medically-treated. Follow-up data was available in 20 surgically-treated and 13 medically-treated patients. Twelve (60%) of the 20 surgically-treated patients recovered completely, and the remaining were left with sequelae or did not improve. In contrast, all the 13 medically-treated patients recovered completely after the use of cysticidal drugs plus corticosteroids (11 cases) or corticosteroids alone (two cases). CONCLUSIONS: Intramedullary cysticercosis is rare. Clinical and neuroimaging findings may resemble those of other intramedullary lesions, but the visualization of the scolex or the incidental discovery of intracranial lesions provide helpful diagnostic clues. Prognosis is benign provided the correct diagnosis is suspected and patients receive prompt therapy.
    Journal of the neurological sciences 06/2013; · 2.32 Impact Factor
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    ABSTRACT: Neurocysticercosis is a widely prevalent disease in the tropics that causes seizures and a variety of neurological symptoms in most of the world. Experimental models are limited and do not allow assessment of the degree of inflammation around brain cysts. The vital dye Evans Blue (EB) was injected to 11 pigs naturally infected with Taenia solium cysts to visually identify the extent of disruption of the bloodbrain barrier. A total of 369 cysts were recovered from the 11 brains and classified according to the staining of their capsules as blue or unstained. The proportion of cysts with blue capsules was significantly higher in brains from pigs that had received anthelmintic treatment 48 and 120 h before the EB infusion, indicating a greater compromise of the blood-brain barrier due to treatment. The model could be useful for understanding the pathology of treatment-induced inflammation in neurocysticercosis.
    Experimental Parasitology 05/2013; 134:443-446. · 2.15 Impact Factor
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    ABSTRACT: BACKGROUND: Serological tests have been used for the diagnosis of Taenia solium infection in pigs. However, those serological results do not necessarily correlate with the actual infection burden after performing pig necropsy. This study aimed to evaluate the Electro Immuno Transfer Blot (EITB) seropositivity with infection burden in naturally infected pigs. METHODOLOGYPRINCIPAL FINDINGS: In an endemic area of Peru, 476 pigs were sampled. Seroprevalence was 60.5±4.5% with a statistically higher proportion of positive older pigs (>8 months) than young pigs. The logistic model showed that pigs >8 month of age were 2.5 times more likely to be EITB-positive than ≤8 months. A subset of 84 seropositive pigs were necropsied, with 45.2% (38/84) positive to 1-2 bands, 46.4% (39/84) to 3 bands, and 8.3% (7/84) to 4+ bands. 41 out of 84 positive pigs were negative to necropsy (48.8%) and 43 (51%) had one or more cysts (positive predictive value). Older pigs showed more moderate and heavy infection burdens compared to younger pigs. In general, regardless of the age of the pig, the probability of having more cysts (parasite burden) increases proportionally with the number of EITB bands. CONCLUSIONSSIGNIFICANCE: The probability of being necropsy-positive increased with the number of bands, and age. Therefore, the EITB is a measure of exposure rather than a test to determine the real prevalence of cysticercosis infection.
    PLoS Neglected Tropical Diseases 05/2013; 7(5):e2192. · 4.57 Impact Factor
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    PLoS Neglected Tropical Diseases 04/2013; 7(4):e1964. · 4.57 Impact Factor

Publication Stats

5k Citations
1,190.81 Total Impact Points


  • 1991–2014
    • Universidad Peruana Cayetano Heredia
      • Facultad de Ciencia y Filosofía
      Λίμα, Provincia de Lima, Peru
  • 2001–2013
    • National Institute of Allergy and Infectious Diseases
      • Laboratory of Parasitic Diseases (LPD)
      Maryland, United States
    • Hospital Clínica Kennedy
      Guayaquil, Guayas, Ecuador
  • 1995–2013
    • National University of San Marcos
      • Facultad de Medicina Veterinaria
      Λίμα, Provincia de Lima, Peru
  • 2012
    • Universidad de Especialidades Espíritu Santo
      Guayaquil, Guayas, Ecuador
    • U.S. Department of Veterans Affairs
      Washington, Washington, D.C., United States
  • 2006–2012
    • University of Melbourne
      • Faculty of Veterinary Science
      Melbourne, Victoria, Australia
  • 2004–2012
    • Johns Hopkins Bloomberg School of Public Health
      • Department of International Health
      Baltimore, MD, United States
  • 2011
    • Hospital Militar Central
      Buenos Aires, Buenos Aires F.D., Argentina
  • 1991–2011
    • Centers for Disease Control and Prevention
      • • Center for Global Health
      • • Division of Parasitic Diseases and Malaria
      Atlanta, MI, United States
  • 2005–2010
    • Imperial College London
      • Division of Infectious Diseases
      London, ENG, United Kingdom
    • National Institute of Health of Peru
      Λίμα, Provincia de Lima, Peru
  • 2009
    • The University of Western Ontario
      London, Ontario, Canada
    • Texas A&M University
      • Department of Veterinary Integrative Biosciences
      College Station, TX, United States
  • 2006–2009
    • National Institutes of Health
      • • National Institute of Allergy and Infectious Diseases (NIAID)
      • • Laboratory of Parasitic Diseases
      Bethesda, MD, United States
  • 2002–2007
    • Johns Hopkins University
      • Department of International Health
      Baltimore, Maryland, United States
  • 2005–2006
    • University of Georgia
      • Department of Cellular Biology
      Athens, GA, United States
  • 2000
    • Baylor College of Medicine
      • Section of Infectious Diseases
      Houston, TX, United States
    • Hospital Luis Vernaza
      Guayaquil, Guayas, Ecuador