Natural Infection of Cichorium intybus (Asteraceae) by Groundnut Ringspot Virus (Genus Orthotospovirus) Isolates in Brazil

Leaf chicory (Cichorium intybus L.) is a nutritionally rich vegetable used in regional cuisine in Brazil. Plants of C. intybus displaying symptoms (viz. chlorotic and necrotic ringspots, mosaic, and leaf deformation) similar to that induced by orthotospoviruses (genus Orthotospovirus, family Tospoviridae) were observed in three fields (≈ 0.2 ha each) in Gama County, in the Federal District, Brazil, from September 2016 to January 2020 in plants of the cultivars ‘Folha-Larga’ and ‘Spadona’ (Fig. 1). Incidence of symptomatic plants was nearly 10% in each field. Transmission electron microscopic examination of thin sections from symptomatic leaf samples showed typical membrane-bounded orthotospovirus particles within cisternae of spongy parenchymal cells (Fig 2). Two individual leaf samples per field were collected and submitted to dot enzyme-linked immunosorbent assay with polyclonal antisera against N protein of tomato spotted wilt virus (TSWV), groundnut ringspot virus (GRSV) and tomato chlorotic spot virus (TCSV). Symptomatic samples strongly reacted only against GRSV antibodies. Total RNA was extracted (Trizol®, Sigma) from all six samples and used as template in RT-PCR assays. The primer J13 (5’-CCCGGATCCAGAGCAAT-3’) was employed for cDNA synthesis using M-MLV reverse transcriptase. PCR assays were done with the primer pair BR60/BR65 (Eiras et al., 2001) to obtain ≈ 500 bp fragment of untranslated region and partial N gene in the S RNA segment from each sample. Purified RT-PCR products of two randomly selected individual samples were directly sequenced (GenBank MW467981 and MZ126602) and their BLASTn analyses displayed 99 to 100% nucleotide identity to GRSV isolates previously reported infecting C. endivia L. in Brazil (Jorge et al., 2021). Our analyses combining N protein serology and N-gene sequencing (both directed to the S RNA segment) allowed us to confirm the GRSV infection of C. intybus, but the potential reassortant nature of these isolates (Webster et al., 2015; Silva et al., 2019) are unknown since their M RNA segments were not characterized. Individual leaf extracts (in phosphate buffer, pH 7.0) of the sequenced isolates were mechanically inoculated onto ten seedlings of two C. intybus cultivars (‘Folha Larga’ and ‘Pão-de-Açúcar’) and three plants each of the indicator hosts Capsicum chinense PI 159236, Nicandra physalodes; Nicotiana rustica; Datura stramonium; and tomato cv. Santa Clara. Systemic chlorotic and necrotic ringspots, mosaic, and leaf deformation developed in the indicator hosts and infection by GRSV was confirmed via serological assays 20 days after inoculation. However, no symptoms and no serological reaction to GRSV antibodies were observed on the C. intybus cultivars even after two successive mechanical inoculations. This transmission failure might be due to factors such as the requirement of the thrips vector(s), physicochemical barriers in the foliage or the presence of non-mechanically transmissible helper agent(s) necessary to ensure GRSV infection of C. intybus. The natural infection of C. intybus by a not fully characterized orthotospovirus (mostly likely TSWV) has been observed since 1938 in Brazil (Kitajima, 2020). Our report of GRSV infecting C. intybus is thus confirming previous speculations that similar symptoms in this vegetable crop were induced by orthotospovirus infection in Brazil. References: Eiras, M. et al. 2001. Fitopatol. Bras. 26: 170. Jorge, T. S. et al. 2021. Plant Dis. 105: 714. Kitajima, E.W. 2020. Biota Neotrop. 20: e2019932. Silva, J. M. F. et al. 2019. Viruses 11: 187. Webster, C.G. et al. 2015. Phytopathology 105: 388.

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Wild Allium spp. as Natural Hosts of Iris yellow spot virus

Plant Disease ◽

10.1094/pd-90-0378a ◽

2006 ◽

Vol 90 (3) ◽

pp. 378-378 ◽

Cited By ~ 7

Author(s):

H. R. Pappu ◽

B. C. Hellier ◽

F. M. Dugan

Keyword(s):

Natural Infection ◽

The State ◽

Thrips Tabaci ◽

Iris Yellow Spot Virus ◽

Yellow Spot ◽

N Gene ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Spot Virus ◽

Sequence Comparisons

The incidence of Iris yellow spot virus (IYSV) of genus Tospovirus, family Bunyaviridae in a commercial onion crop was first confirmed in Washington state during 2003 (1). First found in Adams County, IYSV has rapidly spread to all onion-producing counties in the state, affecting seed and bulb crops. The USDA-ARS Western Regional Plant Introduction Station (WRPIS) collects, maintains, and distributes various Allium (garlic and onion) accessions. As part of the regeneration process, accessions are grown under field conditions at the WRPIS farms in two locations: Pullman and Central Ferry, WA. Symptoms indicative of viral infection, now known to be caused by IYSV, first appeared in field-grown accessions in 1999. In June 2005, leaf and scape tissues were collected from WRPIS accessions of wild onions (Allium pskemense, A. vavilovii, and A. altaicum) in Central Ferry that had symptoms indicative of IYSV infection (2). IYSV infection was confirmed using enzyme-linked immunosorbent assay with a commercially available kit (Agdia Inc., Elkhart, IN). Virus infection was further verified using reverse transcription-polymerase chain reaction (RT-PCR) with primers derived from the small (S) RNA of IYSV. The primers flanked the IYSV N gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′). RT-PCR gave a PCR product of expected size (≈1.2 kb). The DNA amplicon was cloned and sequenced. Nucleotide sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The prevalence of the vector, onion thrips (Thrips tabaci), combined with the widespread incidence of IYSV in seed and bulb production areas of the state may have resulted in natural infection of wild relatives of cultivated onion. The potential role of wild Allium spp. in IYSV epidemiology remains to be determined. Information on the extent of IYSV infection of onion germplasm would be useful in identifying potential sources of host plant resistance to IYSV. References: (1) L. J. du Toit et al. Plant Dis. 88:222, 2004. (2) B. Hellier et al. APSnet Image of the Week. Online publication, iw000049.asp, 2004.

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Evaluation of Sandwich Enzyme-Linked Immunosorbent Assay and Reverse Transcription Polymerase Chain Reaction for the Diagnosis of Foot-and-Mouth Disease

Intervirology ◽

10.1159/000517003 ◽

2021 ◽

pp. 1-6

Author(s):

Salman Khan ◽

Syed Asad Ali Shah ◽

Syed Muhammad Jamal

Keyword(s):

Polymerase Chain Reaction ◽

Viral Genome ◽

Foot And Mouth Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Chain Reaction ◽

Kappa Value ◽

Polymerase Chain ◽

Pcr Assays ◽

Level Of Agreement

Background: Foot-and-mouth disease (FMD) is an infectious and highly contagious disease of cloven-hoofed domestic and wild animals, causing heavy economic losses to the livestock industry. Rapid and reliable diagnosis of the disease is essential for the implementation of effective control measures. This study compared sandwich enzyme-linked immunosorbent assay (S-ELISA) and conventional reverse transcription polymerase chain reaction (RT-PCR) for the diagnosis of FMD. Methods: A total of 60 epithelial samples from suspected cases of FMD were tested using both S-ELISA and RT-PCR assays. The level of agreement between the assays was assessed by calculating the Kappa value. Results: S-ELISA detected 38 (63%) samples positive for FMD virus (FMDV). Being predominant, serotype O was detected in 22 (57.9%) of the total samples tested positive, whereas 9 (23.7%) and 7 (18.4%) samples were found positive for serotypes A and Asia-1, respectively. RT-PCR detected viral genome in 51 (85%) of the samples using pan-FMDV primers set, 1F/1R. Thirty-six samples were found positive and 7 negative by both the tests. The level of agreement between the tests was assessed by calculating the Kappa value, which was found to be fair (Kappa value = 0.303 and 95% CI = 0.089; 0.517) and significant (p = 0.009). However, 2 samples, which were found positive on S-ELISA tested negative on RT-PCR. This may be attributed to the presence of nucleotide mismatch(es) in the primer-binding sites that may have resulted in failure of amplification of the viral genome. The serotype-specific RT-PCR assays not only confirmed serotyping results of S-ELISA but were also able to establish serotype in 9 S-ELISA-negative but pan-FMDV RT-PCR-positive samples. Conclusions: The RT-PCR assay contributes significantly to establishing a quick, sensitive, and definitive diagnosis of FMD in resource-constrained countries. Samples giving negative results in S-ELISA should be tested in RT-PCR for the disease detection and virus typing.

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Comparison of ELISA and RT-PCR assays for the detection of Tomato spotted wilt virus in peanut

Peanut Science ◽

10.3146/ps08-024.1 ◽

2009 ◽

Vol 36 (2) ◽

pp. 133-137 ◽

Cited By ~ 1

Author(s):

P. M. Dang ◽

D. L. Rowland ◽

W. H. Faircloth

Keyword(s):

Tomato Spotted Wilt Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Infection Rates ◽

Rt Pcr ◽

Chi Square ◽

Tomato Spotted Wilt ◽

Significant Difference ◽

Pcr Assays ◽

Chi Square Analysis ◽

Wilt Virus

Abstract Diagnosis of Tomato spotted wilt virus (TSWV) in peanut can be accomplished by enzyme-linked immunosorbent assay (ELISA) or reverse transcription polymerase chain reaction (RT-PCR) but there has been no report of a direct comparison of the success of the two assays in evaluating infection rates of field-grown peanut. We collected peanut root samples from field-grown plants, 76 in 2006 and 48 in 2007, and tested these samples by both ELISA and RT-PCR assays for the presence of TSWV. Out of 124 samples, 50 (40.3%) and 57 (46.0%) were positive for TSWV by ELISA and RT-PCR respectively. In 13.7% of these samples, ELISA and RT-PCR differed in their results. However, Chi square analysis showed no significant difference between the results for these two assays. This result supports the conclusion that ELISA and RT-PCR are comparable for detecting TSWV infection rates in field-grown peanuts.

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First Report of Tomato spotted wilt virus in Blackberry Lily in North America

Plant Disease ◽

10.1094/pdis.2003.87.1.102c ◽

2003 ◽

Vol 87 (1) ◽

pp. 102-102 ◽

Cited By ~ 3

Author(s):

S. Adkins ◽

L. Breman ◽

C. A. Baker ◽

S. Wilson

Keyword(s):

North America ◽

Tomato Spotted Wilt Virus ◽

Amino Acid Sequences ◽

South Florida ◽

N Gene ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

First Report ◽

Tomato Spotted Wilt ◽

Wilt Virus

Blackberry lily (Belamcanda chinensis (L.) DC.) is an herbaceous perennial in the Iridaceae characterized by purple-spotted orange flowers followed by persistent clusters of black fruit. In July 2002, virus-like symptoms including chlorotic ringspots and ring patterns were observed on blackberry lily leaves on 2 of 10 plants in a south Florida ornamental demonstration garden. Inclusion body morphology suggested the presence of a Tospovirus. Tomato spotted wilt virus (TSWV) was specifically identified by serological testing using enzyme-linked immunosorbent assay (Agdia, Elkhart, IN). Sequence analysis of a nucleocapsid (N) protein gene fragment amplified by reverse transcription-polymerase chain reaction (RT-PCR) with primers TSWV723 and TSWV722 (1) from total RNA confirmed the diagnosis. Nucleotide and deduced amino acid sequences of a 579 base pair region of the RT-PCR product were 95 to 99% and 95 to 100% identical, respectively, to TSWV N-gene sequences in GenBank. Since these 2-year-old plants were grown on-site from seed, they were likely inoculated by thrips from a nearby source. Together with a previous observation of TSWV in north Florida nursery stock (L. Breman, unpublished), this represents, to our knowledge, the first report of TSWV infection of blackberry lily in North America although TSWV was observed in plants of this species in Japan 25 years ago (2). References: (1) S. Adkins, and E. N. Rosskopf. Plant Dis. 86:1310, 2002. (2) T. Yamamoto and K.-I. Ohata. Bull. Shikoku Agric. Exp. Stn. 30:39, 1977.

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Detection of Respiratory and Enteric Shedding of Bovine Coronaviruses in Cattle in an Ohio Feedlot

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870201400406 ◽

2002 ◽

Vol 14 (4) ◽

pp. 308-313 ◽

Cited By ~ 44

Author(s):

Mustafa Hasoksuz ◽

Armando E. Hoet ◽

Steven C. Loerch ◽

Thomas E. Wittum ◽

Paul R. Nielsen ◽

...

Keyword(s):

Agricultural Research ◽

Clinical Signs ◽

Feedlot Cattle ◽

N Gene ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Fecal Shedding ◽

Enteric Infections ◽

Antibody Titers ◽

Feedlot Calves

Recently, bovine coronavirus (BCV) has been isolated from new cattle arrivals to feedlots, but the association between respiratory and enteric infections with BCV in feedlot cattle remains uncertain. Fecal and nasal swab samples from 85 Ohio Agricultural Research and Development Center (OARDC) feedlot cattle averaging 7 months of age were collected at arrival (0) and at 4, 7, 14, and 21 days postarrival (DPA). An antigen capture enzyme-linked immunosorbent assay (ELISA) was used to detect concurrent shedding of BCV in fecal and nasal samples. All samples ELISA positive for BCV were matched with an equal number of BCV ELISA-negative samples and analyzed by reverse transcription-polymerase chain reaction (RT-PCR) of the N gene. Paired sera were collected at arrival and 21 DPA and tested for antibodies to BCV using an indirect ELISA. Information on clinical signs, treatments provided, and cattle weights were collected. The overall rates of BCV nasal and fecal shedding were 48% (41/85) and 53% (45/85) by ELISA and 84% (71/85) and 96% (82/85) by RT-PCR, respectively. The peak of BCV nasal and fecal shedding occurred at 4 DPA. Thirty-two cattle (38%) showed concurrent enteric and nasal shedding detected by both tests. Eleven percent of cattle had antibody titers against BCV at 0 DPA and 91% of cattle seroconverted to BCV by 21 DPA. The BCV fecal and nasal shedding detected by ELISA and RT-PCR were statistically correlated with ELISA antibody seroconversion ( P < 0.0001); however, BCV fecal and nasal shedding were not significantly related to clinical signs. Seroconversion to BCV was inversely related to average daily weight gains ( P < 0.06). Twenty-eight respiratory and 7 enteric BCV strains were isolated from nasal and fecal samples of 32 cattle in HRT-18 cell cultures. These findings confirm the presence of enteric and respiratory BCV infections in feedlot calves. Further studies are needed to elucidate the differences between enteric and respiratory strains of BCV and their role in the bovine respiratory disease complex of feedlot cattle.

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Tomato spotted wilt virus Identified in Desert Rose in Florida

Plant Disease ◽

10.1094/pd-89-0526c ◽

2005 ◽

Vol 89 (5) ◽

pp. 526-526 ◽

Cited By ~ 5

Author(s):

S. Adkins ◽

C. A. Baker

Keyword(s):

Tomato Spotted Wilt Virus ◽

The United States ◽

N Gene ◽

Enzyme Linked Immunosorbent Assay ◽

Insect Vector ◽

Rt Pcr ◽

Tomato Spotted Wilt ◽

Wilt Virus ◽

Symptomatic Plant ◽

Das Elisa

Desert rose (Adenium obesum (Forssk.) Roem. & Schult), a member of the family Apocynaceae, is characterized by fleshy stems and leaves and colorful flowers. This exotic ornamental, originally from southeast Africa, is propagated vegetatively and is a perennial in warm climates. Virus-like foliar symptoms, including chlorotic ring and line patterns, were observed in the fall of 2004 on one of five stock plants being maintained in a greenhouse in Fort Pierce, FL. Inclusion body morphology suggested the presence of a Tospovirus in the symptomatic plant, and Tomato spotted wilt virus (TSWV) was specifically identified in this plant using a commercially available double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA; Agdia, Elkhart, IN). TSWV was not detected in symptomless desert rose plants nor was Impatiens necrotic spot virus detected in any of the plants using DAS-ELISA. Graft transmission of TSWV to other desert rose plants was successful. Sequence analysis of a nucleocapsid (N) protein gene fragment amplified by reverse transcription-polymerase chain reaction (RT-PCR) with primers TSWV723 and TSWV722 (1) from total RNA of the symptomatic plant confirmed the diagnosis. Nucleotide and deduced amino acid sequences of a 579-bp region of the RT-PCR product were 95 to 99% and 95 to 100% identical, respectively, to TSWV N-gene sequences in GenBank. No product was amplified from symptomless plants. Since these 3-year-old plants were grown on-site from seed and only expressed symptoms 2 months following damage to the greenhouse by hurricanes Frances and Jeanne, it is likely that viruliferous thrips were introduced from local vegetable or ornamental production areas during or following the storms. To our knowledge, this is the first report of TSWV infection of desert rose in Florida, although TSWV was observed in this plant in Europe approximately 10 years ago (3,4). Because of the wide distribution of TSWV in the United States, the increasing popularity of desert rose, and the recent identification of Cucumber mosaic virus in this host (2), attention to sanitation and insect vector management is merited during desert rose propagation and production. References: (1) S. Adkins and E. N. Rosskopf. Plant Dis. 86:1310, 2002. (2) C. A. Baker et al. Plant Dis. 87:1007, 2003. (3) J. Mertelik et al. Acta Hortic. 432:368, 1996. (4) J. Th. J. Verhoeven and J. W. Roenhorst. Acta Hortic. 377:175, 1994.

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First Report of Alfalfa mosaic virus in Viburnum lucidum in Spain

Plant Disease ◽

10.1094/pdis-92-7-1132b ◽

2008 ◽

Vol 92 (7) ◽

pp. 1132-1132 ◽

Cited By ~ 2

Author(s):

M. C. Cebrián ◽

M. C. Córdoba-Sellés ◽

A. Alfaro-Fernández ◽

J. A. Herrera-Vásquez ◽

C. Jordá

Keyword(s):

Mosaic Virus ◽

Natural Infection ◽

Alfalfa Mosaic Virus ◽

The United States ◽

Rt Pcr ◽

Water Control ◽

First Report ◽

Pcr Product ◽

Pcr Assays ◽

The Mediterranean

Viburnum sp. is an ornamental shrub widely used in private and public gardens. It is common in natural wooded areas in the Mediterranean Region. The genus includes more than 150 species distributed widely in climatically mild and subtropical regions of Asia, Europe, North Africa, and the Americas. In January 2007, yellow leaf spotting in young plants of Viburnun lucidum was observed in two ornamental nurseries in the Mediterranean area of Spain. Symptoms appeared sporadically depending on environmental conditions but normally in cooler conditions. Leaf tissue from 24 asymptomatic and five symptomatic plants was sampled and analyzed by double-antibody sandwich (DAS)-ELISA with specific polyclonal antibodies against Tomato spotted wilt virus (TSWV) (Loewe Biochemica, Sauerlach, Germany) and Alfalfa mosaic virus (AMV) (SEDIAG S.A.S, Longvic, France). All symptomatic plants of V. lucidum were positive for Alfalfa mosaic virus (AMV). The presence of AMV was tested in the 29 samples by one-step reverse transcription (RT)-PCR with the platinum Taq kit (Invitrogen Life Technologies, Barcelona, Spain) using primers derived from a partial fragment of the coat protein gene of AMV (2). The RT-PCR assays produced an expected amplicon of 700 bp in the five symptomatic seropositive samples. No amplification product was observed when healthy plants or a water control were used as a template in the RT-PCR assays. One PCR product was purified (High Pure PCR Product Purification Kit; Roche Diagnostics, Mannheim, Germany) and directly sequenced (GenBank Accession No. EF427449). BLAST analysis showed 96% nucleotide sequence identity to an AMV isolate described from Phlox paniculata in the United States (GenBank Accession No. DQ124429). This virosis has been described as affecting Viburnum tinus L. in France (1). To our knowledge, this is the first report of natural infection of Viburnum lucidum with AMV in Spain, which might have important epidemiological consequences since V. lucidum is a vegetatively propagated ornamental plant. References: (1) L. Cardin et al. Plant Dis. 90:1115, 2006. (2) Ll. Martínez-Priego et al. Plant Dis. 88:908, 2004.

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Comparison of Four Serological Methods and Two Reverse Transcription-PCR Assays for Diagnosis and Surveillance of Zika Virus Infection

Journal of Clinical Microbiology ◽

10.1128/jcm.01785-17 ◽

2018 ◽

Vol 56 (3) ◽

Cited By ~ 33

Author(s):

Angel Balmaseda ◽

José Victor Zambrana ◽

Damaris Collado ◽

Nadezna García ◽

Saira Saborío ◽

...

Keyword(s):

Reverse Transcription ◽

Zika Virus ◽

Clinical Manifestations ◽

Cross Reactivity ◽

Enzyme Linked Immunosorbent Assay ◽

Emerging Infections ◽

Rt Pcr ◽

Convalescent Phase ◽

Reverse Transcription Pcr ◽

Pcr Assays

ABSTRACTZika virus (ZIKV) is a mosquito-borne flavivirus that is responsible for recent explosive epidemics in the Americas. Notably, ZIKV infection during pregnancy has been found to cause congenital birth defects, including microcephaly, and ZIKV has been associated with Guillain-Barré syndrome in adults. Diagnosis and surveillance of Zika in the Americas have been challenging due to similar clinical manifestations and extensive antibody cross-reactivity with endemic flaviviral diseases, such as dengue. We evaluated four serological and two reverse transcription-PCR (RT-PCR) methods in acute-phase (mean day, 1.8), early-convalescent-phase (mean day, 16.7), and late-convalescent-phase (mean, ~7 months) samples from the same individuals in a long-term pediatric cohort study in Nicaragua. Well-characterized samples from 301 cases of Zika, dengue, or non-Zika, nondengue febrile illnesses were tested. Compared to a composite reference, an in-house IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) and the NIAID-Biodefense and Emerging Infections (BEI) MAC-ELISA measuring IgM yielded sensitivities of 94.5% and 70.1% and specificities of 85.6% and 82.8%, respectively. The NS1 blockade-of-binding ELISA measuring anti-ZIKV NS1 antibody levels yielded sensitivities of 85.0% and 96.5% and specificities of 91.4% and 92.6% at early and late convalescence, respectively. An inhibition ELISA detecting total anti-ZIKV antibodies had sensitivity and specificity values of 68.3% and 58.3% for diagnosis and 94.0% and 98.6% for measuring annual infection incidence. Finally, the ZCD and Trioplex real-time RT-PCR assays detecting Zika, chikungunya, and dengue viruses both yielded a sensitivity of 96.1% and specificity of 100%. Together, these assays resolve the urgent need for diagnostic and surveillance tools for countries affected by Zika virus infections.

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411. Application of a SARS-CoV-2-specific serologic assay for translational research and surveillance

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.605 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S273-S273

Author(s):

Amy C Sherman ◽

Teresa C Smith ◽

Daniel Espinoza ◽

Yerun Zhu ◽

Jessica Howard-Anderson ◽

...

Keyword(s):

Sensitivity And Specificity ◽

Roc Curve ◽

Research Training ◽

Natural Infection ◽

Curve Analysis ◽

Antibody Responses ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Research Support ◽

Roc Curve Analysis

Abstract Background Sensitive and specific SARS-CoV-2 antibody diagnostics are urgently needed to estimate the seroprevalence of SARS-CoV-2 infection in both the general population and special risk groups. Moreover, validated serologic assays are critical to understanding immunity to SARS-CoV-2 infection over time and identifying correlates of protection. Methods An enzyme-linked immunosorbent assay (ELISA) protocol to detect antibodies (IgG) that bind the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein was validated and ROC curve analysis performed by testing a large panel of pre-pandemic sera (n=162) and convalescent sera from RT-PCR-confirmed COVID-19 cases (n=60). We then applied this test in two cohorts: 1) Healthcare personnel (HCP) that were enrolled in a longitudinal surveillance cohort just after peak local transmission and 2) Mildly ill patients being tested for SARS-CoV-2 infection by RT-PCR from NP swabs in an ambulatory testing clinic. Demographics of mildly symptomatic patients tested for SARS-CoV-2 with RT-PCR Results ROC curve analysis yielded an AUC of 0.9953, with a sensitivity and specificity at 91.67% and 99.38% at the optimal OD normalization threshold of 0.20. In 240 HCP surveilled at enrollment, 5.83% had positive IgG results. Of 19 symptomatic patients who presented to the ambulatory clinic, 5/19 had a positive PCR. In convalescence (13–74 days post symptom onset), 3 of those 5 were positive for IgG. Validation of the SARS-CoV-2 RBD ELISA ROC Curve Analysis Conclusion We demonstrated high sensitivity and specificity of the SARS-CoV-2 RBD ELISA. This simple assay is an efficient way to track seroconversion and duration of antibody responses to SARS-CoV-2 for different populations, particularly since RBD-binding antibodies have been shown to correlate with neutralization activity and may be useful to determine protective immunity following natural infection or vaccination. Ongoing work will assess variation in magnitude, character and duration of antibody responses in key populations and seek to maximize deployability of large-scale SARS-CoV-2 serology. Disclosures Jessica Howard-Anderson, MD, MSc, Antibacterial Resistance Leadership Group (ARLG) (Other Financial or Material Support, The ARLG fellowship provides salary support for ID fellowship and mentored research training) Nadine Rouphael, MD, Lilly (Grant/Research Support)Merck (Grant/Research Support)Pfizer (Grant/Research Support)Quidel (Grant/Research Support)Sanofi Pasteur (Grant/Research Support)

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Role of Maternal Antibody in Natural Infection ofPeromyscus maniculatus with Sin Nombre Virus

Journal of Virology ◽

10.1128/jvi.74.5.2426-2429.2000 ◽

2000 ◽

Vol 74 (5) ◽

pp. 2426-2429 ◽

Cited By ~ 33

Author(s):

Monica K. Borucki ◽

John D. Boone ◽

Joan E. Rowe ◽

Marlene C. Bohlman ◽

Edward A. Kuhn ◽

...

Keyword(s):

Specific Antibody ◽

Natural Infection ◽

Horizontal Transmission ◽

Sex Bias ◽

Deer Mice ◽

Enzyme Linked Immunosorbent Assay ◽

Sin Nombre Virus ◽

Rt Pcr ◽

Adult Mice ◽

Specific Igg

ABSTRACT Data from naturally infected deer mice (Peromyscus maniculatus) were used to investigate vertical transmission of Sin Nombre virus (SNV) and SNV-specific antibody. The antibody prevalence in juvenile mice (14 g or less) was inversely proportional to the mass of the animal, with juvenile deer mice weighing less than 11 g most likely to be antibody positive (26.9%) and juvenile mice weighing between 13 and 14 g least likely to be antibody positive (12.9%). Although a significant sex bias in seropositivity was detected in adult deer mice, no significant sex bias in seropositivity was detected in juvenile animals. Ten juvenile deer mice were identified that had initially tested positive for SNV-specific immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) but had subsequently tested negative when recaptured as adults. SNV RNA was detected by reverse transcriptase PCR (RT-PCR) in the blood of ELISA-positive adult deer mice but not in the blood of ELISA-positive juveniles. One of the juvenile mice initially tested negative for SNV RNA but later tested positive when recaptured as an ELISA-positive adult. The RT-PCR results for that individual correlated with the disappearance and then reappearance of SNV-specific IgG, indicating that the presence of SNV RNA at later time points was due to infection with SNV via horizontal transmission. SNV-specific antibody present in both ELISA-positive juvenile and adult mice was capable of neutralizing SNV. Additionally, our data indicate that SNV is not transmitted vertically.

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