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Rapp T, Amagai K, Sinai C, Basham C, Loya M, Ngasala S, Said H, Muller MS, Chhetri SB, Yang G, François R, Odas M, Mathias D, Juliano JJ, Lin FC, Ngasala B, Lin JT. Micro-heterogeneity of transmission shapes submicroscopic malaria carriage in coastal Tanzania. J Infect Dis 2024:jiae276. [PMID: 38781438 DOI: 10.1093/infdis/jiae276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 04/14/2024] [Accepted: 05/21/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Asymptomatic carriage of malaria parasites persists even as malaria transmission declines. Low density infections are often submicroscopic, not detected by rapid diagnostic tests (RDTs) or microscopy, but detectable by PCR. METHODS To characterize submicroscopic Plasmodium falciparum carriage in an area of declining malaria transmission, asymptomatic persons >5 years of age in rural Bagamoyo District, Tanzania, were screened using RDT, microscopy, and PCR. We investigated the size of the submicroscopic reservoir of infection across villages, determined factors associated with submicroscopic carriage, and assessed the natural history of submicroscopic malaria over four weeks. RESULTS Among 6,076 participants, P. falciparum prevalence by RDT, microscopy, and PCR was 9%, 9%, and 28%, respectively, with roughly two-thirds of PCR-positive individuals harboring submicroscopic infection. Adult status, female gender, dry season months, screened windows, and bednet use were associated with submicroscopic carriage. Among 15 villages encompassing 80% of participants, the proportion of submicroscopic carriers increased with decreasing village-level malaria prevalence. Over four weeks, 23% (61/266) of submicroscopic carriers became RDT-positive, with half exhibiting symptoms, while half (133/266) were no longer parasitemic at the end of four weeks. Progression to RDT-positive patent malaria occurred more frequently in villages with higher malaria prevalence. CONCLUSIONS Micro-heterogeneity in transmission observed at the village level appears to impact both the size of the submicroscopic reservoir and the likelihood of submicroscopic carriers developing patent malaria in coastal Tanzania.
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Affiliation(s)
- Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Kano Amagai
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Cyrus Sinai
- Department of Geography, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Mwajabu Loya
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, PO Box 65001, Tanzania
| | - Sifa Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, PO Box 65001, Tanzania
| | - Hamza Said
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, PO Box 65001, Tanzania
| | - Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Srijana B Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Guozheng Yang
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Ruthly François
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Melic Odas
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, PO Box 65001, Tanzania
| | - Derrick Mathias
- Florida Medical Entomology Laboratory, Institute of Food & Agricultural Sciences, University of Florida, Vero Beach, FL 32964, USA
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, PO Box 65001, Tanzania
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27514, USA
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Potlapalli VR, Muller MS, Ngasala B, Ali IM, Na YB, Williams DR, Kharabora O, Chhetri S, Liu MS, Carey-Ewend K, Lin FC, Mathias D, Tarimo BB, Juliano JJ, Parr JB, Lin JT. Real-time PCR detection of mixed Plasmodium ovale curtisi and wallikeri infections in human and mosquito hosts. PLoS Negl Trop Dis 2023; 17:e0011274. [PMID: 38064489 PMCID: PMC10732364 DOI: 10.1371/journal.pntd.0011274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 12/20/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023] Open
Abstract
Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) represent distinct non-recombining Plasmodium species that are increasing in prevalence in sub-Saharan Africa. Though they circulate sympatrically, co-infection within human and mosquito hosts has rarely been described. Separate 18S rRNA real-time PCR assays that detect Poc and Pow were modified to allow species determination in parallel under identical cycling conditions. The lower limit of detection was 0.6 plasmid copies/μL (95% CI 0.4-1.6) for Poc and 4.5 plasmid copies/μL (95% CI 2.7-18) for Pow, or 0.1 and 0.8 parasites/μL, respectively, assuming 6 copies of 18s rRNA per genome. However, the assays showed cross-reactivity at concentrations greater than 103 plasmid copies/μL (roughly 200 parasites/μL). Mock mixtures were used to establish criteria for classifying mixed Poc/Pow infections that prevented false-positive detection while maintaining sensitive detection of the minority ovale species down to 100 copies/μL (<1 parasite/μL). When the modified real-time PCR assays were applied to field-collected blood samples from Tanzania and Cameroon, species identification by real-time PCR was concordant with nested PCR in 19 samples, but additionally detected two mixed Poc/Pow infections where nested PCR detected a single Po species. When real-time PCR was applied to oocyst-positive Anopheles midguts saved from mosquitoes fed on P. ovale-infected persons, mixed Poc/Pow infections were detected in 11/14 (79%). Based on these results, 8/9 P. ovale carriers transmitted both P. ovale species to mosquitoes, though both Po species could only be detected in the blood of two carriers. The described real-time PCR approach can be used to identify the natural occurrence of mixed Poc/Pow infections in human and mosquito hosts and reveals that such co-infections and co-transmission are likely more common than appreciated.
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Affiliation(s)
- Varun R. Potlapalli
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Meredith S. Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Innocent Mbulli Ali
- Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Yu Bin Na
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Danielle R. Williams
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Oksana Kharabora
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Srijana Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Mei S. Liu
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Kelly Carey-Ewend
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Derrick Mathias
- Florida Medical Entomology Laboratory, Institute of Food & Agricultural Sciences, University of Florida, Vero Beach, Florida United States of America
| | - Brian B. Tarimo
- Vector Immunity and Transmission Biology Unit, Department of Environmental Health and Ecological Sciences, Ifakara Health Institute-Bagamoyo Office, Bagamoyo, Tanzania
| | - Jonathan J. Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Jonathan B. Parr
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Jessica T. Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
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Rapp T, Amagai K, Sinai C, Basham C, Loya M, Ngasala S, Said H, Muller MS, Chhetri SB, Yang G, François R, Odas M, Mathias D, Juliano JJ, Lin FC, Ngasala B, Lin JT. Micro-heterogeneity of transmission shapes the submicroscopic malaria reservoir in coastal Tanzania. medRxiv 2023:2023.09.06.23295089. [PMID: 37732257 PMCID: PMC10508794 DOI: 10.1101/2023.09.06.23295089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Background Asymptomatic malaria may be patent (visible by microscopy) and detectable by rapid malaria diagnostic tests (RDTs), or it may be submicroscopic and only detectable by polymerase chain reaction (PCR). Methods To characterize the submicroscopic reservoir in an area of declining malaria transmission, asymptomatic persons >5 years of age in Bagamoyo District, Tanzania, were screened using RDT, microscopy, and PCR. We investigated the size of the submicroscopic reservoir across villages, determined factors associated with submicroscopic parasitemia, and assessed the natural history of submicroscopic malaria over four weeks. Results Among 6,076 participants, Plasmodium falciparum prevalence by RDT, microscopy, and PCR was 9%, 9%, and 28%, respectively, with roughly two-thirds of PCR-positive individuals harboring submicroscopic infection. Adult status, female gender, dry season months, screened windows, and bednet use were associated with submicroscopic carriage. Among 15 villages encompassing 80% of participants, the proportion of submicroscopic carriers increased with decreasing village-level malaria prevalence. Over four weeks, 23% (61/266) of submicroscopic carriers became RDT-positive and were treated, with half exhibiting symptoms. This occurred more frequently in villages with higher malaria prevalence. Conclusions Micro-heterogeneity in transmission impacts the size of the submicroscopic reservoir and the likelihood of submicroscopic carriers developing patent malaria in coastal Tanzania.
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Affiliation(s)
- Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Kano Amagai
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Cyrus Sinai
- Department of Geography, University of North Carolina, Chapel Hill, NC USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Mwajabu Loya
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Sifa Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Hamza Said
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Srijana B Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Guozheng Yang
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Ruthly François
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Melic Odas
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Derrick Mathias
- Florida Medical Entomology Laboratory, Institute of Food & Agricultural Sciences, University of Florida, Vero Beach, FL USA
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Feng-Chang Lin
- Department of Geography, University of North Carolina, Chapel Hill, NC USA
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
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Potlapalli V, Muller MS, Ngasala B, Ali IM, Na YB, Williams DR, Kharabora O, Chhetri S, Liu MS, Carey-Ewend K, Lin FC, Mathias D, Tarimo BB, Juliano JJ, Parr J, Lin JT. Real-time PCR detection of mixed Plasmodium ovale curtisi and wallikeri species infections in human and mosquito hosts. bioRxiv 2023:2023.03.31.535020. [PMID: 37034766 PMCID: PMC10081274 DOI: 10.1101/2023.03.31.535020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) represent distinct non-recombining malaria species that are increasing in prevalence in sub-Saharan Africa. Though they circulate sympatrically, co-infection within human and mosquito hosts has rarely been described. Separate 18S rRNA real-time PCR assays that detect Poc and Pow were modified to allow species determination in parallel under identical cycling conditions. The lower limit of detection was 0.6 plasmid copies/μL (95% CI 0.4-1.6) for Poc and 4.5 plasmid copies/μL (95% CI( 2.7- 18) for Pow, or 0.1 and 0.8 parasites/μL, respectively, assuming 6 copies of 18s rRNA per genome. However, the assays showed cross-reactivity at concentrations greater than 103 plasmid copies/μL (roughly 200 parasites/μL). Mock mixtures were used to establish criteria for classifying mixed Poc/Pow infections that prevented false-positive detection while maintaining sensitive detection of the minority ovale species down to 10° copies/μL (<1 parasite/μL). When the modified real-time PCR assays were applied to field-collected blood samples from Tanzania and Cameroon, species identification by real-time PCR was concordant with nested PCR, but additionally detected two mixed Poc/Pow infections where nested PCR detected a single Po species. When real-time PCR was applied to 14 oocyst-positive Anopheles midguts saved from mosquitoes fed on P. ovate-infected persons, mixed Poc/Pow infections were detected in 11 (79%). Based on these results, 8/9 P. ovate carriers transmitted both P. ovate species to mosquitoes, though both Po species could only be detected in the blood of two carriers. The described real-time PCR approach can be used to identify the natural occurrence of mixed Poc/Pow infections in human and mosquito hosts and reveals that such co-infections and co-transmission are likely more common than appreciated.
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Affiliation(s)
- Varun Potlapalli
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Innocent Mbulli Ali
- Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Yu Bin Na
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Danielle R Williams
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC USA
| | - Oksana Kharabora
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Srijana Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Mei S Liu
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Kelly Carey-Ewend
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Derrick Mathias
- Florida Medical Entomology Laboratory, Institute of Food & Agricultural Sciences, University of Florida, Vero Beach, FL USA
| | - Brian B Tarimo
- Vector Immunity and Transmission Biology Unit, Department of Environmental Health and Ecological Sciences, Ifakara Health Institute-Bagamoyo Office, Bagamoyo, Tanzania
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Jonathan Parr
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
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Cerami C, Popkin-Hall ZR, Rapp T, Tompkins K, Zhang H, Muller MS, Basham C, Whittelsey M, Chhetri SB, Smith J, Litel C, Lin KD, Churiwal M, Khan S, Rubinstein R, Claman F, Mollan K, Wohl D, Premkumar L, Powers KA, Juliano JJ, Lin FC, Lin JT. Household Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 in the United States: Living Density, Viral Load, and Disproportionate Impact on Communities of Color. Clin Infect Dis 2022; 74:1776-1785. [PMID: 34383889 PMCID: PMC8436395 DOI: 10.1093/cid/ciab701] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Households are hot spots for severe acute respiratory syndrome coronavirus 2 transmission. METHODS This prospective study enrolled 100 coronavirus disease 2019 (COVID-19) cases and 208 of their household members in North Carolina though October 2020, including 44% who identified as Hispanic or non-White. Households were enrolled a median of 6 days from symptom onset in the index case. Incident secondary cases within the household were detected using quantitative polymerase chain reaction of weekly nasal swabs (days 7, 14, 21) or by seroconversion at day 28. RESULTS Excluding 73 household contacts who were PCR-positive at baseline, the secondary attack rate (SAR) among household contacts was 32% (33 of 103; 95% confidence interval [CI], 22%-44%). The majority of cases occurred by day 7, with later cases confirmed as household-acquired by viral sequencing. Infected persons in the same household had similar nasopharyngeal viral loads (intraclass correlation coefficient = 0.45; 95% CI, .23-.62). Households with secondary transmission had index cases with a median viral load that was 1.4 log10 higher than those without transmission (P = .03), as well as higher living density (more than 3 persons occupying fewer than 6 rooms; odds ratio, 3.3; 95% CI, 1.02-10.9). Minority households were more likely to experience high living density and had a higher risk of incident infection than did White households (SAR, 51% vs 19%; P = .01). CONCLUSIONS Household crowding in the context of high-inoculum infections may amplify the spread of COVID-19, potentially contributing to disproportionate impact on communities of color.
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Affiliation(s)
- Carla Cerami
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Zachary R Popkin-Hall
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Kathleen Tompkins
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Haoming Zhang
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Maureen Whittelsey
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Srijana B Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Judy Smith
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Christy Litel
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Kelly D Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Mehal Churiwal
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Salman Khan
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Rebecca Rubinstein
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Faith Claman
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Katie Mollan
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - David Wohl
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Lakshmanane Premkumar
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Kimberly A Powers
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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Churiwal M, Lin KD, Khan S, Chhetri S, Muller MS, Tompkins K, Smith J, Litel C, Whittelsey M, Basham C, Rapp T, Cerami C, Premkumar L, Lin JT. Assessment of the Field Utility of a Rapid Point-of-Care Test for SARS-CoV-2 Antibodies in a Household Cohort. Am J Trop Med Hyg 2021; 106:156-159. [PMID: 34818625 PMCID: PMC8733539 DOI: 10.4269/ajtmh.21-0592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 10/11/2021] [Indexed: 11/07/2022] Open
Abstract
Point-of-care (POC) tests to detect SARS-CoV-2 antibodies offer quick assessment of serostatus after natural infection or vaccination. We compared the field performance of the BioMedomics COVID-19 IgM/IgG Rapid Antibody Test against an ELISA in 303 participants enrolled in a SARS-CoV-2 household cohort study. The rapid antibody test was easily implemented with consistent interpretation across 14 users in a variety of field settings. Compared with ELISA, detection of seroconversion lagged by 5 to 10 days. However, it retained a sensitivity of 90% (160/177, 95% confidence interval [CI] 85-94%) and specificity of 100% (43/43, 95% CI 92-100%) for those tested 3 to 5 weeks after symptom onset. Sensitivity was diminished among those with asymptomatic infection (74% [14/19], 95% CI 49-91%) and early in infection (45% [29/64], 95% CI 33-58%). When used appropriately, rapid antibody tests offer a convenient way to detect symptomatic infections during convalescence.
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Affiliation(s)
- Mehal Churiwal
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Kelly D. Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Salman Khan
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Srijana Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Meredith S. Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Kathleen Tompkins
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Judy Smith
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Christy Litel
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Maureen Whittelsey
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Carla Cerami
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- MRC Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Lakshmanane Premkumar
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Jessica T. Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Muller MS, Chhetri SB, Basham C, Rapp T, Lin FC, Lin K, Westreich D, Cerami C, Juliano JJ, Lin JT. Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings. Diagn Microbiol Infect Dis 2021; 101:115469. [PMID: 34280773 PMCID: PMC8230941 DOI: 10.1016/j.diagmicrobio.2021.115469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 01/14/2023]
Abstract
Alternatives to nasopharyngeal sampling are needed to increase capacity for SARS-CoV-2 testing. Among 275 participants, we piloted the collection of nasal mid-turbinate swabs amenable to self-testing, including polyester flocked swabs as well as 3D-printed plastic lattice swabs, placed into viral transport media or an RNA stabilization agent. Flocked nasal swabs identified 104/121 individuals who were PCR-positive for SARS-CoV-2 by nasopharyngeal sampling (sensitivity 87%, 95% CI 79-92%), missing those with low viral load (<106 viral copies/mL). 3D-printed nasal swabs showed similar sensitivity. When nasal swabs were placed directly into RNA preservative, the mean 1.4 log decrease in viral copies/uL compared to nasopharyngeal samples was reduced to <1 log, even when samples were left at room temperature for up to 7 days. We also evaluated pooling strategies that involved pooling specimens in the lab versus pooling swabs at the point of collection, finding both successfully detected samples with >105 viral copies/mL.
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Affiliation(s)
- Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
| | - Srijana B Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Kelly Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Daniel Westreich
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Carla Cerami
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
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Cerami C, Rapp T, Lin FC, Tompkins K, Basham C, Muller MS, Whittelsey M, Zhang H, Chhetri SB, Smith J, Litel C, Lin K, Churiwal M, Khan S, Claman F, Rubinstein R, Mollan K, Wohl D, Premkumar L, Juliano JJ, Lin JT. High household transmission of SARS-CoV-2 in the United States: living density, viral load, and disproportionate impact on communities of color. medRxiv 2021:2021.03.10.21253173. [PMID: 33758871 PMCID: PMC7987030 DOI: 10.1101/2021.03.10.21253173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Background Few prospective studies of SARS-CoV-2 transmission within households have been reported from the United States, where COVID-19 cases are the highest in the world and the pandemic has had disproportionate impact on communities of color. Methods and Findings This is a prospective observational study. Between April-October 2020, the UNC CO-HOST study enrolled 102 COVID-positive persons and 213 of their household members across the Piedmont region of North Carolina, including 45% who identified as Hispanic/Latinx or non-white. Households were enrolled a median of 6 days from onset of symptoms in the index case. Secondary cases within the household were detected either by PCR of a nasopharyngeal (NP) swab on study day 1 and weekly nasal swabs (days 7, 14, 21) thereafter, or based on seroconversion by day 28. After excluding household contacts exposed at the same time as the index case, the secondary attack rate (SAR) among susceptible household contacts was 60% (106/176, 95% CI 53%-67%). The majority of secondary cases were already infected at study enrollment (73/106), while 33 were observed during study follow-up. Despite the potential for continuous exposure and sequential transmission over time, 93% (84/90, 95% CI 86%-97%) of PCR-positive secondary cases were detected within 14 days of symptom onset in the index case, while 83% were detected within 10 days. Index cases with high NP viral load (>10^6 viral copies/ul) at enrollment were more likely to transmit virus to household contacts during the study (OR 4.9, 95% CI 1.3-18 p=0.02). Furthermore, NP viral load was correlated within families (ICC=0.44, 95% CI 0.26-0.60), meaning persons in the same household were more likely to have similar viral loads, suggesting an inoculum effect. High household living density was associated with a higher risk of secondary household transmission (OR 5.8, 95% CI 1.3-55) for households with >3 persons occupying <6 rooms (SAR=91%, 95% CI 71-98%). Index cases who self-identified as Hispanic/Latinx or non-white were more likely to experience a high living density and transmit virus to a household member, translating into an SAR in minority households of 70%, versus 52% in white households (p=0.05). Conclusions SARS-CoV-2 transmits early and often among household members. Risk for spread and subsequent disease is elevated in high-inoculum households with limited living space. Very high infection rates due to household crowding likely contribute to the increased incidence of SARS-CoV-2 infection and morbidity observed among racial and ethnic minorities in the US. Quarantine for 14 days from symptom onset of the first case in the household is appropriate to prevent onward transmission from the household. Ultimately, primary prevention through equitable distribution of effective vaccines is of paramount importance.
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Affiliation(s)
- Carla Cerami
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, The Gambia
| | - Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Kathleen Tompkins
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Maureen Whittelsey
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Haoming Zhang
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Srijana B Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Judy Smith
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Christy Litel
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Kelly Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Mehal Churiwal
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Salman Khan
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Faith Claman
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Rebecca Rubinstein
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Katie Mollan
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - David Wohl
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Lakshmanane Premkumar
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
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Muller MS, Chhetri SB, Basham C, Rapp T, Lin FC, Lin K, Westreich D, Cerami C, Juliano JJ, Lin JT. Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings. medRxiv 2021. [PMID: 33655269 PMCID: PMC7924294 DOI: 10.1101/2021.02.18.21251999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Background Standard nasopharyngeal swab testing for SARS-CoV-2 detection by PCR is not always feasible due to limitations in trained personnel, personal protective equipment, swabs, PCR reagents, and access to cold chain and biosafety hoods. Methods We piloted the collection of nasal mid-turbinate swabs amenable to self-testing, including both standard polyester flocked swabs as well as 3D printed plastic lattice swabs, placed into either viral transport media or an RNA stabilization agent. Quantitative SARS-CoV-2 viral detection by RT-qPCR was compared to that obtained by nasopharyngeal sampling as the reference standard. Pooling specimens in the lab versus pooling swabs at the point of collection was also evaluated. Results Among 275 participants, flocked nasal swabs identified 104/121 individuals who were PCR-positive for SARS-CoV-2 by nasopharyngeal sampling (sensitivity 87%, 95% CI 79-92%), mostly missing those with low viral load (<10^3 viral copies/uL). 3D-printed nasal swabs showed similar sensitivity. When nasal swabs were placed directly into an RNA stabilizer, the mean 1.4 log decrease in viral copies/uL compared to nasopharyngeal samples was reduced to <1 log, even when samples were left at room temperature for up to 7 days. Pooling sample specimens or swabs both successfully detected samples >102 viral copies/uL. Conclusions Nasal swabs are likely adequate for clinical diagnosis of acute infections to help expand testing capacity in resource-constrained settings. When collected into an RNA preservative that also inactivates infectious virus, nasal swabs yielded quantitative viral loads approximating those obtained by nasopharyngeal sampling.
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Affiliation(s)
- Meredith S Muller
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Srijana Bhattarai Chhetri
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Christopher Basham
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Tyler Rapp
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Feng-Chang Lin
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Kelly Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Daniel Westreich
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | - Carla Cerami
- MRC Unit The Gambia at the London School of Hygiene & Tropical Medicine
| | - Jonathan J Juliano
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - Jessica T Lin
- Institute of Global Health and Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC USA
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Accinelli MM, Muller MS. [A disturbing finding: recent mortality trends in Argentina]. Notas Poblacion 1978; 6:9-18. [PMID: 12263591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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