Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-30 (of 53 Records) |
Query Trace: Handali S[original query] |
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Convenience sampling for pandemic surveillance of severe acute respiratory syndrome coronavirus 2 in children in Jackson, Mississippi
Inagaki K , Penny A , Gwyn S , Malloch L , Martin L , Hankins E , Ray C , Byers P , Harrison A , Handali S , Martin D , Hobbs CV . Pediatr Infect Dis J 2024 We assessed severe acute respiratory syndrome coronavirus 2 seroprevalence on residual blood samples for pediatric COVID-19 surveillance: 2263 samples were collected during routine outpatient visits (<18 years, April 2020-August 2021). Seroprevalence increased over time, coinciding with or preceding virus circulation in the community and with or preceding pediatric severe COVID-19 hospitalization peaks. Residual blood sample seroprevalence may be a useful surveillance tool in future outbreaks. |
The performance of a point-of-care test for the diagnosis of Neurocysticercosis in a resource-poor community setting in Zambia – a diagnostic accuracy study
Zulu G , Stelzle D , Mwape KE , Van Damme I , Trevisan C , Mubanga C , Schmidt V , Phiri IK , Mambo R , Chembensofu M , Masuku M , Ruether C , Noh J , Handali S , Bottieau E , Magnussen P , Dorny P , Fleury A , Winkler AS , Gabriël S . eClinicalMedicine 2024 77 Background: Neurocysticercosis (NCC) is the main cause of epilepsy in Taenia solium endemic rural communities. NCC diagnosis is difficult due to unavailability and unaffordability of serologic assays and neuroimaging. This study aimed to assess the performance of a cheap, novel T. solium lateral-flow point-of-care (TS POC) test for the diagnosis of NCC in a community setting. Methods: A diagnostic accuracy study with prospective data collection, using a two-stage design was conducted in Sinda district of the Eastern province of Zambia between December 2017 and June 2019. Eligible participants were tested with the TS POC test. Thereafter, participants with a TS POC CC+ result and a subset of participants with a TS POC CC− result were subjected to serological testing for reference assays, and cerebral computed tomography (CT) for the reference diagnosis of NCC. Findings: A total of 1249 participants were tested with the TS POC of which 177 (14%) were positive. Of the 151 TS POC CC+ and 82 TS POC CC− participants with cerebral CT examination, 35 TS POC CC+ and 10 TS POC CC−, respectively, had NCC. The sensitivity of the TS POC CC strip was 26% (uncertainty interval [UI] 15–41) for any type of NCC, which was similar to that estimated for the rT24H-EITB (23%, UI 8–48) and the serum antigen ELISA (30%, UI 11–58). The specificity was 88% (UI 85–90) for the TS POC, 89% (UI 79–94) for the rT24H-EITB, and 82% (UI 71–89) for the antigen ELISA. For NCC with active stage lesions, sensitivity was >99% (UI 58-->99) for the TS POC, 76% (UI 40–94) for the rT24H-EITB and 76% (UI 39–94) for the antigen ELISA. Interpretation: The TS POC CC had a promising sensitivity for diagnosis of participants with active NCC lesions within a community-based setting. Accuracy for NCC at any stage was limited for all tests (TS POC, rT24H-EITB and antigen ELISA). With further development the TS POC CC may enable a better detection and faster referral of NCC patients who may benefit from antiparasitic treatment. Funding: European and Developing Countries Clinical Trials Partnership (EDCTP) and the German Federal Ministry of Education and Research (BMBF). © 2024 The Authors |
Deep humoral profiling coupled to interpretable machine learning unveils diagnostic markers and pathophysiology of schistosomiasis
Saha A , Chakraborty T , Rahimikollu J , Xiao H , de Oliveira LBP , Hand TW , Handali S , Secor WE , AOFraga L , Fairley JK , Das J , Sarkar A . Sci Transl Med 2024 16 (765) eadk7832 ![]() ![]() Schistosomiasis, a highly prevalent parasitic disease, affects more than 200 million people worldwide. Current diagnostics based on parasite egg detection in stool detect infection only at a late stage, and current antibody-based tests cannot distinguish past from current infection. Here, we developed and used a multiplexed antibody profiling platform to obtain a comprehensive repertoire of antihelminth humoral profiles including isotype, subclass, Fc receptor (FcR) binding, and glycosylation profiles of antigen-specific antibodies. Using Essential Regression (ER) and SLIDE, interpretable machine learning methods, we identified latent factors (context-specific groups) that move beyond biomarkers and provide insights into the pathophysiology of different stages of schistosome infection. By comparing profiles of infected and healthy individuals, we identified modules with unique humoral signatures of active disease, including hallmark signatures of parasitic infection such as elevated immunoglobulin G4 (IgG4). However, we also captured previously uncharacterized humoral responses including elevated FcR binding and specific antibody glycoforms in patients with active infection, helping distinguish them from those without active infection but with equivalent antibody titers. This signature was validated in an independent cohort. Our approach also uncovered two distinct endotypes, nonpatent infection and prior infection, in those who were not actively infected. Higher amounts of IgG1 and FcR1/FcR3A binding were also found to be likely protective of the transition from nonpatent to active infection. Overall, we unveiled markers for antibody-based diagnostics and latent factors underlying the pathogenesis of schistosome infection. Our results suggest that selective antigen targeting could be useful in early detection, thus controlling infection severity. |
Cross-sectional study of soil-transmitted helminthiases in Black Belt Region of Alabama, USA
Poole C , Barker T , Bradbury R , Capone D , Chatham AH , Handali S , Rodriguez E , Qvarnstrom Y , Brown J . Emerg Infect Dis 2023 29 (12) 2461-2470 We conducted a cross-sectional study to determine the prevalence of soil-transmitted helminthiases (STH) in areas of rural Alabama, USA, that have sanitation deficits. We enrolled 777 children; 704 submitted stool specimens and 227 a dried blood spot sample. We microscopically examined stool specimens from all 704 children by using Mini-FLOTAC for helminth eggs. We tested a subset by using molecular techniques: real-time PCR analysis for 5 STH species, TaqMan Array Cards for enteric helminths, and digital PCR for Necator americanus hookworm. We analyzed dried blood spots for Strongyloides stercoralis and Toxocara spp. roundworms by using serologic testing. Despite 12% of our cohort reporting living in homes that directly discharge untreated domestic wastewater, stool testing for STH was negative; however, 5% of dried blood spots were positive for Toxocara spp. roundworms. Survey data suggests substantial numbers of children in this region may be exposed to raw sewage, which is itself a major public health concern. |
Multiantigen print immunoassay (MAPIA) for the diagnosis of neurocysticercosis: a single-center diagnostic optimization and accuracy study in Lima, Peru
Toribio L , Guzman C , Noazin S , Zimic-Sheen A , Zimic M , Gonzales I , Saavedra H , Pretell EJ , Bustos JA , Handali S , García HH . J Clin Microbiol 2023 61 (12) e0076023 Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system. The antibody detection assay of choice is the enzyme-linked immunoelectrotransfer blot assay using lentil-lectin purified parasite antigens (LLGP-EITB, Western blot), an immunoassay with exceptional performance in clinical samples. However, its use is mainly restricted to a few research laboratories because the assay is labor-intensive and requires sophisticated equipment, expertise, and large amounts of parasite material for preparation of reagents. We report a new immunoprint assay (MAPIA) that overcomes most of these barriers. We initially compared the performance of five different antigen combinations in a subset of defined samples in the MAPIA format. After selecting the best-performing assay format (a combination of rGP50 + rT24H + sTs14 antigens), 148 archived serum samples were tested, including 40 from individuals with parenchymal NCC, 40 with subarachnoid NCC, and 68 healthy controls with no evidence of neurologic disease. MAPIA using three antigens (rGP50 + rT24H + sTs14) was highly sensitive and specific for detecting antibodies in NCC. It detected 39 out of 40 (97.5%) parenchymal NCC cases and 40/40 (100%) subarachnoid cases and was negative in 67 out of 68 (98.53%) negative samples. MAPIA using three recombinant and synthetic antigens is a simple and economical tool with a performance equivalent to the LLGP-EITB assay for the detection of specific antibodies to NCC. The MAPIA overcomes existing barriers to adoption of the EITG LLGP and is a candidate for worldwide use. |
Evaluation of a point-of-care test for the diagnosis of Taenia solium neurocysticercosis in rural southern Tanzania: a diagnostic accuracy study
Stelzle D , Makasi CE , Schmidt V , Van Damme I , Trevisan C , Ruether C , Fleury A , Noh J , Handali S , Dorny P , Magnussen P , Zulu G , Mwape KE , Bottieau E , Gabriël S , Ngowi BJ , Winkler AS . Lancet Infect Dis 2023 24 (1) 98-106 BACKGROUND: Neurocysticercosis is a common cause of epilepsy in Taenia solium-endemic areas in sub-Saharan Africa but is often undiagnosed because of an absence of affordable diagnostic tools. This study evaluated the diagnostic accuracy of a T solium cysticercosis antibody-detecting lateral-flow point-of-care assay (TS POC test) for the neuroimaging-based diagnosis of neurocysticercosis. METHODS: Patients with epileptic seizures or severe progressive headache were recruited consecutively from three hospitals in southern Tanzania. All patients were tested with the TS POC test. All patients positive for cysticercosis on the TS POC test and every tenth patient who was negative for cysticercosis received a brain CT examination and underwent reference testing for T solium cysticercosis (ie, rT24H-EITB, LLGP-EITB, and antigen ELISA). The primary outcome of the study was the sensitivity of the TS POC test for the diagnosis of neurocysticercosis. FINDINGS: Of the 601 recruited participants, 102 (17%) tested positive for cysticercosis with the TS POC test. Overall, 48 (62%) of the 77 patients positive for cysticercosis and five (17%) of the 29 patients negative for cysticercosis on the TS POC test had CT-confirmed neurocysticercosis. The TS POC test yielded a sensitivity of 49% (uncertainty interval [UI] 41-58) for neurocysticercosis. Sensitivity was similar to that of the rT24H-EITB (44%, UI 37-51) and the antigen ELISA (50%, 43-56). For the subset of neurocysticercosis cases with at least one active (ie, vesicular) lesion, sensitivity was above 98% for the TS POC test, the rT24H-ETIB, and the antigen ELISA. INTERPRETATION: The TS POC test showed promising results for the diagnosis of neurocysticercosis in patients with vesicular lesions, which need to be confirmed in a larger study. This test could be considered to support policies on screening patients with suspected neurocysticercosis in clinical settings, which would allow appropriate referral for neuroimaging and early treatment. FUNDING: German Federal Ministry of Education and Research and the European & Developing Countries Clinical Trials Partnership. TRANSLATION: For the Swahili translation of the abstract see Supplementary Materials section. |
A rapid point-of-care assay for cysticercosis antigen detection in urine samples
Toribio L , Handali S , Marin Y , Perez E , Castillo Y , Bustos JA , O'Neal SE , Garcia HH . Am J Trop Med Hyg 2023 108 (3) 578-580 We report a proof-of-concept study using a dipstick assay to detect Taenia solium antigen in urine samples of 30 patients with subarachnoid neurocysticercosis and 10 healthy control subjects. Strips were read in blind by two readers. The assay detected antigen in 29 of 30 cases and was negative in all 10 control samples. Although this study was performed in samples from individuals with subarachnoid neurocysticercosis who likely had high circulating antigen levels, it provides the proof of concept for a functional urine antigen point-of-care assay that detects viable cysts. Such an assay could serve to support a clinical diagnosis of suspect neurocysticercosis or to identify patients at risk of developing severe disease in areas where medical resources are limited, providing evidence to refer these individuals for imaging and specialized care as needed. |
Evaluation of the performance of Ortho T. cruzi ELISA test system for the detection of antibodies to trypanosoma cruzi
Rivera HN , McAuliffe I , Aderohunmu T , Wiegand RE , Montgomery SP , Bradbury RS , Handali S . J Clin Microbiol 2022 60 (8) e0013422 The serologic diagnosis of chronic Chagas disease, caused by infection with the parasite Trypanosoma cruzi, is challenging and lacks a gold-standard assay. To overcome the problem, CDC uses an algorithm that uses two tests on different platforms and applies a third test as a tiebreaker. The Ortho T. cruzi ELISA Test System from Ortho Diagnostics was cleared by FDA for clinical diagnosis usage. We evaluated this test against the CDC algorithm for chronic Chagas disease. We tested several sets of serum specimens: 104 specimens tested positive for T. cruzi specific antibody and 283 (including 30 specimens positive for antibody to Leishmania spp.) tested negative based on the current CDC chronic T. cruzi infection diagnostic testing algorithm. Concordance of the Ortho T. cruzi ELISA Test System with the CDC algorithm result was 90% (95% CI 87 to 93%) overall and 92% (95% CI 89 to 95%) when excluding Leishmania spp. antibody positive specimens. The cross-reactivity of the Ortho T. cruzi ELISA Test System was 37% to Leishmania spp. serologically positive specimens, 1% to specimens from patients diagnosed with other parasitic infections, and 0% against specimens from a US noninfected population. In conclusion, the Ortho T. cruzi ELISA Test System compares well against the CDC diagnostic algorithm for chronic Chagas disease. The availability of this FDA-cleared assay will improve the chronic Chagas disease diagnosis. |
Improved diagnosis of viable parenchymal neurocysticercosis by combining antibody banding patterns on enzyme-linked immunoelectrotransfer blot (EITB) with antigen ELISA assay
Arroyo G , Bustos JA , Lescano AG , Gonzales I , Saavedra H , Pretell EJ , Castillo Y , Perez E , Handali S , Noh J , Dorny P , Gilman RH , O'Neal S , Gonzalez A , Garcia H . J Clin Microbiol 2021 60 (2) Jcm0155021 The diagnosis of NCC depends on neuroimaging and serological confirmation. While antibody detection by enzyme-linked immunoelectrotransfer blot (EITB) fails to predict viable NCC, EITB banding patterns provide information about the host's infection course. Adding antigen ELISA results on EITB banding patterns may improve their ability to predict or rule out of viable NCC. We assessed whether combining EITB banding patterns with Ag-ELISA improves discrimination of viable infection in imaging-confirmed parenchymal NCC. EITB banding patterns were grouped into classes using latent class analysis. True-positive and false-negative Ag-ELISA results in each class were compared using Fisher's exact test. Four classes were identified: 1 (EITB-negative or positive to GP50 alone [GP50 antigen family]), 2 (positive to GP42-39 and GP24 [T24/42 family], with or without GP50), 3 and 4 (positive to GP50, GP42-39 and GP24, and reacting to bands in the 8-kDa family). Most cases in classes 3 and 4 had viable NCC (82% and 88%) compared to classes 2 and 1 (53% and 5%). Adding positive Ag-ELISA results to class 2 predicted all viable NCC cases (22/22 [100%]), whereas 11/40 patients (27.5%) Ag-ELISA negative had viable NCC (P < 0.001). Only 1/4 patients (25%) Ag-ELISA positive in class 1 had viable NCC, whereas 1/36 patients (2.8%) Ag-ELISA negative had viable NCC (P = 0.192). In classes 3 and 4, adding Ag-ELISA was not contributory. Combining Ag-ELISA with EITB banding patterns improves discrimination of viable from non-viable NCC, particularly for class-2 responses. Together, these complement neuroimaging more appropriately for the diagnosis of viable NCC. |
Evaluation of an Antibody Detecting Point of Care Test for Diagnosis of Taenia solium Cysticercosis in a Zambian Rural Community: A Prospective Diagnostic Accuracy Study
Mubanga C , Van Damme I , Trevisan C , Schmidt V , Phiri IK , Zulu G , Noh J , Handali S , Mambo R , Chembensofu M , Masuku M , Reynders D , Jansen F , Bottieau E , Magnussen P , Winkler AS , Dorny P , Mwape KE , Gabriël S . Diagnostics (Basel) 2021 11 (11) ![]() The lack of cheap, easy-to-use, rapid diagnostic tests has led to the development of several rapid diagnostic tests for cysticercosis. The new prototype two-strip, Taenia solium point of care test (TS POC) detects antibodies against taeniosis (TS POC T) and cysticercosis (TS POC CC). This study evaluated the diagnostic performance of the TS POC CC in the Sinda district in eastern Zambia. A sample of 1254 participants was recruited and tested with the TS POC. Out of the 1249 participants with a valid TS POC result, 177 (14%) tested positive while 1072 (86%) tested negative. All individuals with a positive TS POC and a subset of negative TS POC participants were selected for serum sampling, and were subjected to the recombinant glycoprotein T24H enzyme-linked immunoelectrotransfer blot (rT24H EITB) and the serum B60/158 (serum Ag) enzyme-linked immunosorbent assay (Ag ELISA). Performance characteristics were estimated using a Bayesian approach with probabilistic constraints. Based on 255 complete cases, the estimated sensitivity and specificity of the TS POC CC test were 35% (95% CI: 14-63%) and 87% (95% CI: 83-90%), respectively. The diagnostic performance needs to be improved, possibly by titrating antigen and other reagents' concentration in the strip to produce a performance similar to existing cysticercosis tests such as the rT24H EITB. |
Challenges encountered when evaluating an antibody-detecting point-of-care test for taeniosis in an endemic community in Zambia: A prospective diagnostic accuracy study
Mubanga C , Trevisan C , Van Damme I , Schmidt V , Phiri IK , Zulu G , Noh J , Handali S , Mambo R , Chembensofu M , Masuku M , Reynders D , Jansen F , Bottieau E , Magnussen P , Winkler AS , Dorny P , Mwape KE , Gabriel S . Diagnostics (Basel) 2021 11 (11) ![]() Taenia solium taeniosis diagnosis is challenging because current tests perform sub-optimally and/or are expensive, require sophisticated equipment, infrastructure and trained manpower, and therefore are not community deployable. A recently-developed, multi-strip, T. solium point-of-care test (TS POC) for simultaneous detection of tapeworm (TS POC T) and cysticercus (TS POC CC) human antibodies was evaluated for diagnostic accuracy on consecutively recruited community participants in Sinda district, Zambia. All participants were tested using the TS POC test. All test-positives and 20% of the test-negative participants were invited to give a blood and stool sample for reference testing. Three different reference tests were used for taeniosis diagnosis: recombinant rES33 enzyme-linked immunoelectrotransfer blot (rES33 EITB), copro PCR and copro Ag ELISA. Bayesian analysis with probabilistic constraints was used to estimate sensitivity and specificity. In total, 1254 participants were tested with the TS POC test, of whom 13 tested positive using the TS POC T. Based on 161 participants with complete data, the estimated sensitivity and specificity for the TS POC T test were 38% (95% CI: 5–93%) and 99% (95% CI: 98–100%), respectively. The challenge of highly variable inter-assay performance is highlighted. We recommend either increasing the sensitivity or redesigning the test. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. |
Development of nucleic-acid lateral flow immunoassay for rapid and accurate detection of Chikungunya virus in Indonesia.
Ajie M , Pascapurnama DN , Prodjosoewojo S , Kusumawardani S , Djauhari H , Handali S , Alisjahbana B , Chaidir L . J Microbiol Biotechnol 2021 31 (12) 1716-1721 ![]() ![]() Chikungunya fever is an arboviral disease caused by the Chikungunya virus (CHIKV). The disease has similar clinical manifestations with other acute febrile illnesses which complicates differential diagnosis in low-resource settings. We aimed to develop a rapid test for CHIKV detection based on the nucleic acid lateral flow immunoassay technology. The system consisted of a primer set that recognized the E1 region of the CHIKV genome and tagged with FITC/biotin and test strips in an in-housed cassette which detects amplicons labeled with FITC/biotin. Amplification of the viral genome was done using open-source PCR, a low-cost open-source thermal cycler. Assay performance was evaluated using a panel of RNA isolated from patients' blood with confirmed CHIKV (n=8) and dengue virus (n=20) infection. The open-source PCR-NALFIA platform had a limit of detection of 10 RNA copies/ml. The assay had a sensitivity and specificity of 100% (95% CI: 67.56% - 100%) and 100% (95% CI: 83.89% - 100%), respectively, compared to reference standards of any positive virus culture on C6/36 cell lines and/or qRT-PCR. Further evaluation of its performance using a larger sample size may provide important data to extend its usefulness, especially its utilization in the peripheral healthcare facilities with scarce resources and outbreak situations. |
Development of a Multiplex Bead Assay To Detect Immunoglobulin G Antibodies to Babesia duncani in Human Serum.
Wang Y , Aderohunmu T , Bishop H , McAuliffe I , Rivera HN , Smith D , Wilkins PP , Bowden KE , Reed MS , Svoboda P , Stuchlik O , Pohl J , Wiegand RE , Handali S . J Clin Microbiol 2021 59 (11) Jcm0045821 ![]() ![]() Babesia duncani is the causative agent of babesiosis in the western United States. The indirect fluorescent antibody (IFA) assay is the diagnostic test of choice for detection of B. duncani specific antibodies. However, this test requires parasitized red blood cells harvested from infected hamsters and test results are often difficult to interpret. To simplify serological testing for B. duncani, a proteomics approach was employed to identify candidate immunodiagnostic antigens. Several proteins were identified by electrospray ionization (ESI) mass spectrometric analysis and four recombinant protein constructs were expressed and used in a multiplex bead assay (MBA) to detect B. duncani-specific antibodies. Two antigens, AAY83295.1 and AAY83296.1, performed well with high sensitivities and specificities. AAY83295.1 had a higher sensitivity (100%) but lower specificity (89%) in comparison to AAY83296.1, which had a sensitivity of 90% and a specificity of 96%. Combining these two antigens did not improve the performance of the assay. This MBA could be useful for diagnosis, serosurveillance, and blood donor screening for B. duncani infection. |
Parasitic disease surveillance, Mississippi, USA
Bradbury RS , Lane M , Handali S , Cooley G , Montgomery SP . Emerg Infect Dis 2021 27 (8) 2201-2204 Surveillance for soil-transmitted helminths, strongyloidiasis, cryptosporidiosis, and giardiasis was conducted in Mississippi, USA. PCR performed on 224 fecal samples for all soil-transmitted helminths and on 370 samples for only Necator americanus and Strongyloides stercoralis identified 1 S. stercoralis infection. Seroprevalences were 8.8% for Toxocara, 27.4% for Cryptosporidium, 5.7% for Giardia, and 0.2% for Strongyloides parasites. |
Multiplex Bead Assay for the Detection of Human IgG Antibody Responses to African Trypanosomes.
Priest JW , Handali S . Am J Trop Med Hyg 2021 105 (5) 1193-1197 ![]() The recent introduction of large-scale, population-based serologic surveys in several nations where human African trypanosomiasis (HAT) remains endemic could provide an opportunity to better map the remaining disease foci and to identify asymptomatic, seropositive individuals who are infected with the more chronic form of the parasite, Trypanosoma brucei gambiense (gHAT). We have incorporated a soluble form of variant surface glycoprotein 117 and a recombinant invariant surface glycoprotein 65.1 into a multiplex bead assay (MBA) method that is commonly used for the detection of IgG antibody responses to other neglected tropical diseases. A positive result was defined as reactivity to both antigens. MBA sensitivity and specificity for gHAT infection were 92% and 96%, respectively. Assay specificity for the acute form of disease caused by T.b. rhodesiense (rHAT) was 94%, but the sensitivity was only 63.6%. In the future, additional antigens could be incorporated into the multiplex assay to improve rHAT sensitivity. |
Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world
Bustos J , Gonzales I , Saavedra H , Handali S , Garcia HH . J Neurol Sci 2021 427 117527 Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each. |
Development of rSs-NIE-1 and rSs-IR Recombinant Antigen-Based Immunoblot for Detection of Antibody to Strongyloides stercoralis
de Souza JN , Langford I , Wang Y , Soares NM , Handali S . Am J Trop Med Hyg 2021 104 (6) 2038-2041 Strongyloides stercoralis is a soil-transmitted nematode that can cause life-threatening conditions in immunocompromised persons. In the United States, strongyloidiasis should be considered mainly in immigrants, refugees, or travelers. The confirmatory laboratory diagnosis is usually performed by detecting larvae from the stool, duodenal material, and sputum. In persons who are immunocompromised with severe strongyloidiasis, adult worms and eggs can be detected from duodenal material. For serological diagnosis, most assays use crude antigens to detect anti-S. stercoralis IgG. Recently, recombinant proteins such as rSs-NIE-1 and rSs-IR have been used to detect IgG antibodies. We used rSs-NIE-1 and rSs-IR recombinant antigens to develop a biplex Western blot assay to detect the IgG4 antibody in individuals with strongyloidiasis. The sensitivities of rSs-NIE-1 and rSs-IR were 97.4% and 90.8%, respectively, whereas the specificities were 97.6% and 98%, respectively. In conclusion, the biplex rSs-NIE-1 and rSs-IR immunoblot performs well in detecting IgG4 antibody in S. stercoralis-infected persons. |
A Bead-Based Assay for the Detection of Antibodies against Trichinella Spp. Infection in Humans
Kahsay R , Gomez-Morales MA , Rivera HM , McAuliffe I , Pozio E , Handali S . Am J Trop Med Hyg 2021 104 (5) 1858-1862 Human trichinellosis can be diagnosed by a combination of medical history, clinical presentation, and laboratory findings, and through detection of anti-Trichinella IgG in the patient's sera. ELISA using excretory-secretory (E/S) antigens of Trichinella spiralis larvae is currently the most used assay to detect Trichinella spp. antibodies. Bead-based assay can detect antibodies to multiple antigens concurrently; the ability to detect antibody to T. spiralis using a bead assay could be useful for diagnosis and surveillance. We developed and evaluated a bead assay to detect and quantify total IgG or IgG4 Trichinella spp. antibodies in human serum using T. spiralis E/S antigens. The sensitivity and specificity of the assay were determined using serum from 110 subjects with a confirmed diagnosis of trichinellosis, 140 subjects with confirmed infections with other tissue-dwelling parasites, 98 human serum samples from residents of the United States with no known history of parasitic infection, and nine human serum samples from residents of Egypt with negative microscopy for intestinal parasites. Sensitivity and specificity were 93.6% and 94.3% for total IgG and 89.2% and 99.2% for IgG4, respectively. Twelve percent of sera from patients with confirmed schistosomiasis reacted with the IgG Trichinella bead assay, as did 11% of sera from patients with neurocysticercosis. The Trichinella spp. bead assay to detect IgG total antibody responses has a similar performance as the Trichinella E/S ELISA. The Trichinella spp. bead assay shows promise as a method to detect trichinellosis with a possibility to be used in multiplex applications. |
Identification of cross-reactive markers to strengthen the development of immunodiagnostic methods for angiostrongyliasis and other parasitic infections
Cognato BB , Handali S , de Mattos Pereira L , Barradas JR , Januário da Silva A , Graeff-Teixeira C , Morassutti AL . Exp Parasitol 2020 218 107999 Angiostrongylus cantonensis is the main causative agent of eosinophilic meningoencephalitis (EoM) in humans. Molecular diagnostic methods are essential since the identification of larvae in cerebrospinal fluid (CSF) is extremely rare. To date, the detection of a 31 kDa antigen by Western blotting has been the primary immunodiagnostic method for EoM caused by A. cantonensis. However, cross-reactivity with other parasites has been observed. Therefore, we conducted a comparative analysis using sera from individuals with angiostrongyliasis. We also characterized proteins isolated from different cellular sources of A. cantonensis, Toxocara canis, Schistosoma mansoni, and Strongyloides stercoralis with mass spectrometry. A total of 115 cross-reactive proteins were identified. Three of these proteins, heat shock protein, an intermediate filament protein, and galectin 1, represent potential markers for cross-reactivity. In addition, synthetic peptides were generated from previously identified diagnostic targets and tested against sera from individuals infected with several other parasites. As a result, two other markers of cross-reactivity were identified: peptide #4 derived from the 14-3-3 protein and peptide #12 derived from the Lec-5 protein. In contrast, 34 proteins were exclusively present in the Angiostrongylus extracts and represent promising diagnostic molecules for specific identification of A. cantonensis infection. In particular, cytochrome oxidase subunit I is of great interest as a possible immunodiagnostic target for angiostrongyliasis. |
Parasitic Infection Surveillance in Mississippi Delta Children.
Bradbury RS , Arguello I , Lane M , Cooley G , Handali S , Dimitrova SD , Nascimento FS , Jameson S , Hellmann K , Tharp M , Byers P , Montgomery SP , Haynie L , Kirmse B , Pilotte N , Williams SA , Hobbs CV . Am J Trop Med Hyg 2020 103 (3) 1150-1153 ![]() Some recent studies suggest ongoing transmission of parasitic diseases in the American South; however, surveys in Mississippi children are lacking. We enrolled 166 children (median age 8 years, range 4-13 years) from the Mississippi Delta region and carried out multi-parallel real-time polymerase chain reaction (PCR) for Necator americanus, Ascaris lumbricoides, and Strongyloides stercoralis on their stool samples. Dried blood spots were obtained for multiplex serology antibody detection. Of 166 children, all reported having flushable toilets, 11% had soil exposure, and 34% had a pet dog or cat. None had prior diagnosis or treatment of parasitic disease. Multi-parallel real-time PCRs were negative on the 89 stool DNA extracts available for testing. Dried blood spot testing of all 166 children determined the seroprevalence of IgG antibodies to Toxocara spp. (3.6%), Cryptosporidium (2.4%), S. stercoralis, Fasciola hepatica, and Giardia duodenalis (all 0%). In conclusion, parasitic infections and exposure were scarce in this population. Larger studies of at-risk populations are needed. |
Antibody epitope repertoire analysis enables rapid antigen discovery and multiplex serology.
Kamath K , Reifert J , Johnston T , Gable C , Pantazes RJ , Rivera HN , McAuliffe I , Handali S , Daugherty PS . Sci Rep 2020 10 (1) 5294 ![]() ![]() The detection of pathogen-specific antibodies remains a cornerstone of clinical diagnostics. Yet, many test exhibit undesirable performance or are completely lacking. Given this, we developed serum epitope repertoire analysis (SERA), a method to rapidly discover conserved, pathogen-specific antigens and their epitopes, and applied it to develop an assay for Chagas disease caused by the protozoan parasite Trypanosoma cruzi. Antibody binding peptide motifs were identified from 28 Chagas repertoires using a bacterial display random 12-mer peptide library and next-generation sequencing (NGS). Thirty-three motifs were selected and mapped to candidate Chagas antigens. In a blinded validation set (n = 72), 30/30 Chagas were positive, 30/30 non-Chagas were negative, and 1/12 Leishmania sp. was positive. After unblinding, a Leishmania cross-reactive epitope was identified and removed from the panel. The Chagas assay exhibited 100% sensitivity (30/30) and specificity (90/90) in a second blinded validation set including individuals with other parasitic infections. Amongst additional epitope repertoires with unknown Chagas serostatus, assay specificity was 99.8% (998/1000). Thus, the Chagas assay achieved a combined sensitivity and specificity equivalent or superior to diagnostic algorithms that rely on three separate tests to achieve high specificity. NGS-based serology via SERA provides an effective approach to discover antigenic epitopes and develop high performance multiplex serological assays. |
Alcohol consumption alters anti-Strongyloides stercoralis antibodies production
De Souza JN , Cruz ADV , Araujo WAC , Sampaio LM , Allegretti SM , Teixeira MCA , Handali S , Galvao-Castro B , Soares NM . Immunobiology 2019 225 (2) 151898 Individuals infected with Strongyloides stercoralis have been reported to produce different immunoglobulins isotypes, yet few studies have evaluated their use in strongyloidiasis diagnosis. The aim of this work was to evaluate the immunoreactivity of different classes and subclasses of anti-S. stercoralis circulating antibodies in alcoholic patients by ELISA and to perform immunoblotting in samples with discordant results between parasitological and immunological methods. 345 male patients with a clinical diagnosis of alcoholism hospitalized at a reference center for alcoholics in Salvador, Bahia, Brazil, were included in this study. The fecal samples were examined by three different parasitological methods (spontaneous sedimentation, Baermann-Moraes and Agar Plate Culture methods). The ELISA was performed for the detection of IgG, IgG1, IgG4, IgE and IgA1 anti-S. stercoralis. Immunoblotting, for the detection of specific IgA1, was used to elucidate discordant results between parasitological and immunological methods. S. stercoralis infection frequency in alcoholic patients by parasitological methods was 21.4% (74/345). Although IgE-ELISA demonstrated a high sensitivity and specificity in non-alcoholic patients, about 30% (22/74) of alcoholics with larvae in feces were negative. IgG1-ELISA detected the lowest frequency of antibodies in alcoholic patients with larvae in feces, only 57% (42/74). IgG4-ELISA was the best assay for S. stercoralis infection immunodiagnosis. Immunoreactivity in the immunoblotting for IgA1 at 90, 75, 26 and/or 17kDa bands was observed in 92% (33/36) of alcoholics with larvae excretion and negative ELISA for one or more antibody isotypes. In conclusion, IgG4-ELISA showed the highest sensitivity and specificity, thus demonstrating its superiority for strongyloidiasis immunodiagnosis in alcoholic and non-alcoholic individuals. Both, IgE and IgG1-ELISA presented high sensitivities and specificities for S. stercoralis infection diagnosis in non-alcoholics, however there was low reactivity in alcoholic individuals. This can be associated with an increased susceptibility to severe strongyloidiasis in these patients. IgA1-immunoblotting can be used to confirm S. stercoralis infection when there are discordant results between parasitological methods and ELISA. |
Feasibility of a point-of-care test based on quantum dots with a mobile phone reader for detection of antibody responses
Lee C , Noh J , O'Neal SE , Gonzalez AE , Garcia HH , Handali S . PLoS Negl Trop Dis 2019 13 (10) e0007746 We developed a novel and portable fluorescent sensor that integrates a lateral flow assay with a quantum dot (Qdots) label and a mobile phone reader for detection of specific antibodies in human serum. We evaluated the utility of this assay to test for antibodies to the Taenia solium rT24H antigen. It was a retrospective study by examining 112 positive human sera from patients with neurocysticercosis (NCC) including samples from patients with single viable cyst (n = 18), two or more viable cysts (n = 71), and subarachnoid (racemose) cysts (n = 23). These samples were collected from previous study subjects in Lima, Peru that conducted under an approved study protocol in Peru. The sera were made anonymous under a protocol approved by the CDC Institutional Review Board. Definitive diagnosis of the specimen was established by computed-tomography and/or magnetic resonance imaging. To test the specificity of the assay, we evaluated a panel of serum samples obtained from patients with other infections (n = 24), and serum samples from persons in the United States and Egypt who had not traveled outside their country, and therefore are presumed negative for cysticercosis (n = 128). The assay specificity in the negative panel was 99% (95-100%) while assay sensitivity was 89% (79-95%) in NCC patients with two or more viable cysts. Our assay has performance characteristics similar to those of traditional platforms for the detection of NCC and shows promise as a mobile phone reader-based point-of-care test for antibody detection. |
Lack of evidence for Toxocara infection in Italian myelitis patients
Nicoletti A , Garcia HH , Cicero CE , Portaro G , Giuliano L , Patti F , Sofia V , Noh J , Handali S , Zappia M . Neurol Sci 2019 41 (1) 239-241 Acute myelitis is a common neurological manifestation due to different causes, but in about 15-30% of cases its etiology remains unknown (idiopathic myelitis). Myelitis represents the most common manifestation of neurotoxocariasis, the infection of the human nervous system by larvae of the nematode Toxocara spp.; however, despite the high seroprevalence worldwide, its contribution to the burden of disease has not been assessed. We evaluated the presence of antibodies against Toxocara spp. in cerebrospinal fluid (CSF) from a sample of 28 patients with a diagnosis of idiopathic myelitis (N = 20) or encephalomyelitis (N = 8) who attended the Neurological Unit of the University Hospital of Catania, Sicily. Antibodies against Toxocara spp. were measured using a multiplex bead-based assay and Toxocara immunoblot using Toxocara canis excretory secretory antigens. All samples tested negative for the presence of anti-T. canis IgG antibodies. In this series, we found no evidence of a contribution of neurotoxocariasis to the burden of myelitis. |
Human seroprevalence to 11 zoonotic pathogens in the U.S. Arctic, Alaska
Miernyk KM , Bruden D , Parkinson AJ , Hurlburt D , Klejka J , Berner J , Stoddard RA , Handali S , Wilkins PP , Kersh GJ , Fitzpatrick K , Drebot MA , Priest JW , Pappert R , Petersen JM , Teshale E , Hennessy TW , Bruce MG . Vector Borne Zoonotic Dis 2019 19 (8) 563-575 BACKGROUND: Due to their close relationship with the environment, Alaskans are at risk for zoonotic pathogen infection. One way to assess a population's disease burden is to determine the seroprevalence of pathogens of interest. The objective of this study was to determine the seroprevalence of 11 zoonotic pathogens in people living in Alaska. METHODS: In a 2007 avian influenza exposure study, we recruited persons with varying wild bird exposures. Using sera from this study, we tested for antibodies to Cryptosporidium spp., Echinococcus spp., Giardia intestinalis, Toxoplasma gondii, Trichinella spp., Brucella spp., Coxiella burnetii, Francisella tularensis, California serogroup bunyaviruses, and hepatitis E virus (HEV). RESULTS: Eight hundred eighty-seven persons had sera tested, including 454 subsistence bird hunters and family members, 160 sport bird hunters, 77 avian wildlife biologists, and 196 persons with no wild bird exposure. A subset (n = 481) of sera was tested for California serogroup bunyaviruses. We detected antibodies to 10/11 pathogens. Seropositivity to Cryptosporidium spp. (29%), California serotype bunyaviruses (27%), and G. intestinalis (19%) was the most common; 63% (301/481) of sera had antibodies to at least one pathogen. Using a multivariable logistic regression model, Cryptosporidium spp. seropositivity was higher in females (35.7% vs. 25.0%; p = 0.01) and G. intestinalis seropositivity was higher in males (21.8% vs. 15.5%; p = 0.02). Alaska Native persons were more likely than non-Native persons to be seropositive to C. burnetii (11.7% vs. 3.8%; p = 0.005) and less likely to be seropositive to HEV (0.4% vs. 4.1%; p = 0.01). Seropositivity to Cryptosporidium spp., C. burnetii, HEV, and Echinococcus granulosus was associated with increasing age (p </= 0.01 for all) as was seropositivity to >/=1 pathogen (p < 0.0001). CONCLUSION: Seropositivity to zoonotic pathogens is common among Alaskans with the highest to Cryptosporidium spp., California serogroup bunyaviruses, and G. intestinalis. This study provides a baseline for use in assessing seroprevalence changes over time. |
Detection and evaluation of antibody response to a Baylisascaris-specific antigen in rodent hosts with the use of Western blotting and ELISA
Sapp SGH , Handali S , Weinstein SB , Yabsley MJ . J Parasitol 2018 104 (6) 651-659 Diagnosis of parasitic diseases that involve tissue-stage larvae is challenging, and serology remains the most effective antemortem test for detecting these infections. Baylisascaris procyonis, the raccoon roundworm, is a zoonotic ascarid. Raccoons are the usual definitive host, and humans may be infected as accidental hosts. More than 150 species of birds and mammals may act as paratenic hosts, and rodents play an important role in the transmission and maintenance of this parasite in nature. Migratory larvae in paratenic host tissues can produce ocular disease and severe to fatal neurologic disease, but not all infected hosts develop signs. A sensitive and specific Western blot (WB) assay based on a recombinant Baylisascaris-specific antigen (rBpRAG-1) has been developed for use in humans. We evaluated the use of this antigen to detect Baylisascaris spp. infections in rodent paratenic hosts. With the use of 4 species of Peromyscus mice ( Peromyscus californicus, Peromyscus leucopus, Peromyscus maniculatus, Peromyscus polionotus) from a previous infection trial, we developed species-adapted WB and ELISA assays and evaluated performance compared to detection of larvae in tissue samples. These assays revealed species-level differences in seroconversion and terminal antibody concentrations, with P. leucopus developing significantly greater antibody concentrations than P. californicus and P. polionotus at all dose levels, and P. maniculatus at the low dose. Some P. californicus and P. polionotus failed to seroconvert despite the recovery of larvae from their tissues. WB and ELISA results were correlated; however, the WB demonstrated higher sensitivity than the ELISA overall (72.2% versus 63.9%, respectively). With the use of experimental samples, specificity was 100% for WB and 94.1% for ELISA. A WB was also used to test Mus and Rattus samples, and although numbers were too limited to evaluate sensitivity and specificity, all animals known to be infected by tissue digestion were WB positive, and all uninfected animals were negative. Finally, the Peromyscus-adapted WB and ELISA were used to test a set of serum samples from wild-trapped P. maniculatus and Rattus rattus. Both assays were generally sensitive, but specificity was equivocal. This emphasizes the challenge of using serology for investigation of wildlife diseases, in which hosts have unknown exposure histories. Nevertheless, serologic methods have utility in the study of Baylisascaris spp. in paratenic hosts, either wild or captive, and have advantageous attributes (non-lethal, high-throughput), but results should be interpreted carefully. |
Concurrent seroprevalence of antibodies to Toxoplasma gondii and Toxocara species in the United States, 2011- 2014
Liu EW , Elder S , Rivera H , Kruszon-Moran D , Handali S , Jones JL . Clin Infect Dis 2018 68 (4) 712-713 We report supplemental findings incorporating Toxoplasma gondii serology results from our study of risk factors for Toxocara seropositivity in the United States [1] using stored serum samples collected from the National Health and Nutrition Examination Survey (NHANES), 2011–2014. Whereas T. gondii is a protozoan parasite and Toxocara is an intestinal nematode, both share ingestion of contaminated soil as means of exposure in humans. Both parasites can contaminate soil when environmentally resistant T. gondii oocysts or Toxocara cati eggs are shed in the feces of infected cats [2, 3]. |
The epidemiology of porcine Taenia solium cysticercosis in communities of the Central Highlands in Vietnam
Ng-Nguyen D , Noh J , Breen K , Stevenson MA , Handali S , Traub RJ . Parasit Vectors 2018 11 (1) 360 ![]() BACKGROUND: Taenia solium cysticercosis, recognized as a neglected tropical disease by the WHO, is distributed mostly in developing countries of Latin America, sub-Saharan Africa and Asia. Pigs and humans act as intermediate hosts, acquiring T. solium cysticerci (larval stage) in their tissue, through the ingestion of T. solium eggs shed in the faeces of humans infected with adult tapeworms. The disease has a negative impact on rural economies due to losses in productivity arising from human disease, pork carcass condemnations and loss of market access. The aim of this study was to estimate the prevalence of T. solium cysticercosis in pigs in Dak Lak Province in the Central Highlands of Vietnam and to identify household level characteristics associated with T. solium porcine cysticercosis. METHODS: This was a cross-sectional study of household pigs in three districts of Dak Lak Province. A total of 408 households in six villages in three districts were visited between June and October 2015. A questionnaire was administered to the head of each household, and within each household, serum samples were collected from three pigs. Serum samples were analyzed using the recombinant T24H antigen in enzyme-linked immunoelectrotransfer blot assay and lentil lectin purified glycoprotein in EITB assay. A Bayesian, mixed-effects logistic regression model was developed to identify management factors associated with the probability of a household having at least one cysticercosis-positive pig. RESULTS: The prevalence of porcine T. solium cysticercosis in this study was low at 0.94 [95% confidence interval (CI) 0.51-1.68] cases per 100 pigs at risk, in agreement with other studies conducted throughout Vietnam. Scavenging of food and coprophagy were associated with T. solium cysticercosis [odds ratios 1.98 (95% CrI: 0.55-4.74) and 2.57 (95% CrI: 1.22-4.66), respectively]. CONCLUSIONS: This study proves that the seroprevalence of porcine cysticercosis in Dak Lak Province was as low as that of other studies conducted throughout Vietnam. Scavenging of food and coprophagy are modifiable factors, providing the opportunity to decrease the prevalence of porcine cysticercosis further in the province. |
Laboratory diagnosis of neurocysticercosis/Taenia solium
Garcia HH , O'Neal SE , Noh J , Handali S . J Clin Microbiol 2018 56 (9) Neurocysticercosis accounts for approximately 30% of all epilepsy cases in most developing countries. Immunodiagnosis of cysticercosis is complex and strongly influenced by the course of infection, the disease burden and cyst location, and the immune response of the host. The main approach to immunodiagnosis should thus be to evaluate whether the serological results are consistent with the diagnosis suggested by imaging. Antibody detection is performed using lentil-lectin purified parasite antigens in an enzyme-linked immunoelectrotransfer blot format while antigen detection uses a monoclonal antibody-based ELISA. Promising new assay configurations have been developed for detection of both antibody and antigen, including assays based on synthetic or recombinant antigens that may reduce costs and improve assay reproducibility, and multiplex bead based assays that may provide simultaneous quantitative results for several target antigens or antibodies. |
Detection of immunoglobulin G antibodies to Taenia solium cysticercosis antigen glutathione-S-transferase-rT24H in Malian children using multiplex bead assay
Moss DM , Handali S , Chard AN , Trinies V , Bullard S , Wiegand RE , Doumbia S , Freeman MC , Lammie PJ . Am J Trop Med Hyg 2018 98 (5) 1408-1412 Blood samples from 805 students attending 42 elementary schools in Mopti, Sikasso, and Koulikoro regions, and Bamako district in Mali participated in a school water, sanitation, and hygiene intervention. Immunoglobulin (Ig) G responses to several antigens/pathogens were assessed by a multiplex bead assay (MBA), and the recombinant Taenia solium T24H antigen was included. Of all students tested, 8.0% were positive to rT24H, but in some schools 25-30%. A cluster of 12 widespread school locations showed not only a relative risk of 3.23 for T. solium exposure and significantly higher IgG responses (P < 0.001) but also significantly lower elevation (P = 0.04) (m, above sea level) compared with schools outside the cluster. All schools at elevations < 425 m showed significantly higher IgG responses (P = 0.017) than schools at elevations >/= 425 m. The MBA is an excellent serological platform that provides cost-effective opportunities to expand testing in serosurveys. |
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