...some of the central nervous system features of toxocariasis have been implicated as a cause of occult seizures, mental retardation, and developmental delays 3,4,15. Because pica is a risk factor ...for both toxocariasis and lead ingestion 16, it is possible that an element of the cognitive and mental deficits ascribed to toxocariasis may partially result from plumbism. ...the larvae may remain alive within the host for months, and host antibody levels may remain strongly positive for 2 or 3 years or more 17,31. ...in the CDC EIA, the presence of antibody titers greater than 1:32 may be considered reflective of active infection, although we are not aware of careful studies that have determined the length of persistent toxocaral antibodies over long periods of time.
Abstract Rapid diagnosis of leptospirosis, through culture and/or serology, can be difficult without proper expertise and is often delayed because of the length of time required to obtain results. In ...this study, we developed a real-time polymerase chain reaction (PCR) assay using a TaqMan probe targeting lipL32 , which is present only in pathogenic Leptospira spp. Using Leptospira interrogans serovar Icterohaemorrhagiae DNA, the lower limit of detection was found to be 20 genomic equivalents/reaction with a 95% cutoff value. The assay detected pathogenic Leptospira strains, but not intermediately pathogenic or nonpathogenic strains. When testing the assay on spiked clinical specimens, whole blood and plasma were better specimens for detecting the same initial number of leptospires compared with serum from clotted and centrifuged blood. Leptospira spiked at the same concentration was better detected in centrifuged urine. This real-time PCR assay with high specificity and sensitivity may prove to be a rapid method for diagnosing acute leptospirosis.
Background. On 21 November 2005, a 32-year-old male resident of New York was hospitalized with suspected leptospirosis. He had participated in an endurance-length swamp race on 4–5 November 2005 ...outside of Tampa, Florida. Methods. We interviewed racers to assess illness, medical care, and race activities. A suspected case was defined as fever plus es;2 signs or symptoms of leptospirosis occurring in a racer after 4 November 2005. Individuals with suspected cases were referred for treatment as needed and were asked to submit serum samples for microscopic agglutination testing (MAT) and for rapid testing by the dot enzyme-linked immunosorbent assay dipstick immunoglobulin M immunoassay. Results. The Centers for Disease Control and Prevention and participating state health departments interviewed 192 (96%) of 200 racers from 32 states and Canada. Forty-four (23%) of 192 racers met the definition for a suspected case. The median age of the patients was 37 years (range, 19–66 years), and 128 (66.7%) were male. Fourteen (45%) of the 31 patients with suspected cases who were tested had their cases confirmed by serological testing (a single sample with MAT titer es;400), including the index case patient. Organisms of a potential novel serovar (species Leptospira noguchii) were isolated in culture from 1 case patient. Factors associated with increased risk of leptospirosis included swallowing river water (odds ratio OR, 3.4; 95% confidence interval CI, 1.6–7.0), swallowing swamp water (OR, 2.4; 95% CI, 1.1–5.2), and being submerged in any water (OR, 2.3; 95% CI, 1.1–4.7). Conclusions. This report describes a leptospirosis outbreak that resulted in a high rate of symptomatic infection among adventure racers in Florida. The growing popularity of adventure sports may put more people at risk for leptospirosis, even in areas that have not previously been considered areas of leptospirosis endemicity.
Toxoplasma gondii is a ubiquitous parasite that can cause neurologic and ocular disease. We tested sera from 7,072 people ≥ 6 years of age in the 2009-2010 National Health and Nutrition Examination ...Survey (NHANES) for immunoglobulin G antibodies and compared these results with two previous NHANES studies. The overall T. gondii antibody seroprevalence among persons ≥ 6 years of age in 2009-2010 was 13.2% (95% confidence limit CL 11.8%, 14.5%) and age-adjusted seroprevalence was 12.4% (95% CL 11.1%, 13.7%); age-adjusted seroprevalence among women 15-44 years of age was 9.1% (95% CL 7.2%, 11.1%). In U.S. born persons 12-49 years of age, the age-adjusted T. gondii seroprevalence decreased from 14.1% (95% CL 12.7%, 15.5%) in NHANES III (1988-1994) to 9.0% (95% CL 7.6%, 10.5%) in NHANES 1999-2004 to 6.7% (95% CL 5.3%, 8.2%) in NHANES 2009-2010 (P < 0.001 linear trend). Although T. gondii antibody presence is still relatively common, the prevalence in the United States has continued to decline.
Babesia microti, an intraerythrocytic parasite, is tickborne in nature. In contrast to transmission by blood transfusion, which has been well documented, transmission associated with solid organ ...transplantation has not been reported. We describe parasitologically confirmed cases of babesiosis diagnosed ≈8 weeks posttransplantation in 2 recipients of renal allografts from an organ donor who was multiply transfused on the day he died from traumatic injuries. The organ donor and recipients had no identified risk factors for tickborne infection. Antibodies against B. microti parasites were not detected by serologic testing of archived pretransplant specimens. However, 1 of the organ donor's blood donors was seropositive when tested postdonation and had risk factors for tick exposure. The organ donor probably served as a conduit of Babesia parasites from the seropositive blood donor to both kidney recipients. Babesiosis should be included in the differential diagnosis of unexplained fever and hemolytic anemia after blood transfusion or organ transplantation.
Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the ...Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity.
Epilepsy is common in developing countries, and it is often associated with parasitic infections. We investigated the relationship between exposure to parasitic infections, particularly multiple ...infections and active convulsive epilepsy (ACE), in five sites across sub-Saharan Africa.
A case-control design that matched on age and location was used. Blood samples were collected from 986 prevalent cases and 1,313 age-matched community controls and tested for presence of antibodies to Onchocerca volvulus, Toxocara canis, Toxoplasma gondii, Plasmodium falciparum, Taenia solium and HIV. Exposure (seropositivity) to Onchocerca volvulus (OR = 1.98; 95%CI: 1.52-2.58, p<0.001), Toxocara canis (OR = 1.52; 95%CI: 1.23-1.87, p<0.001), Toxoplasma gondii (OR = 1.28; 95%CI: 1.04-1.56, p = 0.018) and higher antibody levels (top tertile) to Toxocara canis (OR = 1.70; 95%CI: 1.30-2.24, p<0.001) were associated with an increased prevalence of ACE. Exposure to multiple infections was common (73.8% of cases and 65.5% of controls had been exposed to two or more infections), and for T. gondii and O. volvulus co-infection, their combined effect on the prevalence of ACE, as determined by the relative excess risk due to interaction (RERI), was more than additive (T. gondii and O. volvulus, RERI = 1.19). The prevalence of T. solium antibodies was low (2.8% of cases and 2.2% of controls) and was not associated with ACE in the study areas.
This study investigates how the degree of exposure to parasites and multiple parasitic infections are associated with ACE and may explain conflicting results obtained when only seropositivity is considered. The findings from this study should be further validated.
The clinical spectrum of human disease caused by the roundworms Toxocara canis and Toxocara cati ranges from visceral and ocular larva migrans to covert toxocariasis. The parasite is not typically ...recovered in affected tissues, so detection of parasite-specific antibodies is usually necessary for establishing a diagnosis. The most reliable immunodiagnostic methods use the Toxocara excretory-secretory antigens (TES-Ag) in ELISA formats to detect Toxocara-specific antibodies. To eliminate the need for native parasite materials, we identified and purified immunodiagnostic antigens using 2D gel electrophoresis followed by electrospray ionization mass spectrometry. Three predominant immunoreactive proteins were found in the TES; all three had been previously described in the literature: Tc-CTL-1, Tc-TES-26, and Tc-MUC-3. We generated Escherichia coli expressed recombinant proteins for evaluation in Luminex based immunoassays. We were unable to produce a functional assay with the Tc-MUC-3 recombinant protein. Tc-CTL-1 and Tc-TES-26 were successfully coupled and tested using defined serum batteries. The use of both proteins together generated better results than if the proteins were used individually. The sensitivity and specificity of the assay for detecting visceral larval migrans using Tc-CTL-1 plus Tc-TES-26 was 99% and 94%, respectively; the sensitivity for detecting ocular larval migrans was 64%. The combined performance of the new assay was superior to the currently available EIA and could potentially be employed to replace current assays that rely on native TES-Ag.
We compared a nested PCR assay and microscopic examination of Giemsa-stained blood films for detection and identification of Plasmodium spp. in blood specimens. PCR was more sensitive than microscopy ...and capable of identifying malaria parasites at the species level when microscopy was equivocal.
Objective
To evaluate the diagnostic performance of two commercially available ELISA kits, Novalisa® and Ridascreen®, for the detection of antibodies to Taenia solium, compared to serological ...diagnosis of neurocysticercosis (NCC) by LLGP‐EITB (electro‐immunotransfer blot assay using lentil‐lectin purified glycoprotein antigens).
Methods
Archive serum samples from patients with viable NCC (n = 45) or resolved, calcified NCC (n = 45), as well as sera from patients with other cestode parasites (hymenolepiasis, n = 45 and cystic hydatid disease, n = 45), were evaluated for cysticercosis antibody detection using two ELISA kits, Novalisa® and Ridascreen®. All NCC samples had previously tested positive, and all samples from heterologous infections were negative on LLGP‐EITB for cysticercosis. Positive rates were calculated by kit and sample group and compared between the two kits.
Results
Compared to LLGP‐EITB, the sensitivity of both ELISA assays to detect specific antibodies in patients with viable NCC was low (44.4% and 22.2%), and for calcified NCC, it was only 6.7% and 4.5%. Sera from patients with cystic hydatid disease were highly cross‐reactive in both ELISA assays (38/45, 84.4%; and 25/45, 55.6%). Sera from patients with hymenolepiasis cross‐reacted in five cases in one of the assays (11.1%) and in only one sample with the second assay (2.2%).
Conclusions
The performance of Novalisa® and Ridascreen® was poor. Antibody ELISA detection cannot be recommended for the diagnosis of neurocysticercosis.
Objectif
Evaluer la performance diagnostique de deux kits ELISA disponibles dans le commerce, Novalisa® et Ridascreen®, pour la détection d'anticorps de Taenia solium, comparés au diagnostic sérologique de la neurocysticercose (NCC) par LLGP‐EITB (test électro immunotransfert blot utilisant des antigènes purifiés de glycoprotéine de lentil‐lectine).
Méthodes
Des échantillons stockés de sérum de patients atteints de NCC viables ou résolues (n = 45), de NCC calcifiée (n = 45), ainsi que des sérums de patients avec d'autres parasites cestodes (hyménolépiase, n = 45 et hydatidose kystique, n = 45), ont été évalués pour la détection d'anticorps de cysticercose en utilisant deux kits ELISA, Novalisa® et Ridascreen®. Tous les échantillons de NCC avaient déjà été testés positifs et tous les échantillons provenant d'infections hétérologues étaient négatifs avec le test LLGP‐EITB pour la cysticercose. Les taux de positivité ont été calculés par kit et par groupe d’échantillons et comparés entre les deux kits.
Résultats
Comparé au test LLGP‐EITB, la sensibilité des deux tests ELISA pour la détection des anticorps spécifiques dans la NCC viable était faible (44,4% et 22,2%) et seulement 6,7% et 4,5% pour la NCC calcifiée. Les sérums provenant de patients atteints d'une hydatidose kystique présentaient une forte réactivité croisée dans les deux tests ELISA (38/45, 84,4% et 25/45, 55,6%). Les sérums des patients atteints d'hyménolépiase ont réagi de manière croisée dans cinq cas avec un des tests (11,1%) et dans un cas avec le second test (2,2%).
Conclusions
Les performances de Novalisa® et de Ridascreen® étaient médiocres. La détection ELISA d'anticorps ne peut pas être recommandée pour le diagnostic de neurocysticercose.
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