Last data update: Apr 16, 2024. (Total: 46543 publications since 2009)
Records 1-24 (of 24 Records) |
Query Trace: Pray IW [original query] |
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Description of a University COVID-19 Outbreak and Interventions to Disrupt Transmission, Wisconsin, August – October 2020 (preprint)
Currie DW , Moreno GK , Delahoy MJ , Pray IW , Jovaag A , Braun KM , Cole D , Shechter T , Fajardo GC , Griggs C , Yandell BS , Goldstein S , Bushman D , Segaloff HE , Kelly GP , Pitts C , Lee C , Grande KM , Kita-Yarbro A , Grogan B , Mader S , Baggott J , Bateman AC , Westergaard RP , Tate JE , Friedrich TC , Kirking HL , O'Connor DH , Killerby ME . medRxiv 2021 2021.05.07.21256834 University settings have demonstrated potential for COVID-19 outbreaks, as they can combine congregate living, substantial social activity, and a young population predisposed to mild illness. Using genomic and epidemiologic data, we describe a COVID-19 outbreak at the University of Wisconsin (UW)–Madison. During August – October 2020, 3,485 students tested positive, including 856/6,162 students living in residence halls. Case counts began rising during move-in week for on-campus students (August 25-31, 2020), then rose rapidly during September 1-11, 2020. UW-Madison initiated multiple prevention efforts, including quarantining two residence halls; a subsequent decline in cases was observed. Genomic surveillance of cases from Dane County, where UW-Madison is located, did not find evidence of transmission from a large cluster of cases in the two residence halls quarantined during the outbreak. Coordinated implementation of prevention measures can effectively reduce SARS-CoV-2 spread in university settings and may limit spillover to the community surrounding the university.Competing Interest StatementThe findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Use of trade names is for identification only and does not imply endorsement by the Centers for Disease Control and Prevention.Clinical TrialN/A.Funding StatementG.K.M. is supported by an NLM training grant to the Computation and Informatics in Biology and Medicine Training Program (NLM 5T15LM007359). This work was funded in part by the U.S. Centers for Disease Control and Prevention Contract #75D30120C09870: Defining the Role of College Students in SARS-CoV-2 Spread in the Upper Midwest.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:A waiver of HIPAA Authorization was obtained by the Western Institutional Review Board (WIRB #1-1290953-1) to obtain the clinical specimens for whole genome sequencing. This analysis was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy. These activities were determined to be non-research public health surveillance by the Institutional Review Board at UW-Madison.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll sequencing data is available on www.gisaid.org. Scripts for sequence data analysis is available at https://github.com/gagekmoreno/SARS-CoV-2-at-UW_Madison. https://github.com/gagekmoreno/SARS-CoV-2-at-UW_Madison |
Loss of Taste and Smell as Distinguishing Symptoms of COVID-19 (preprint)
Dawson P , Rabold EM , Laws RL , Conners EE , Gharpure R , Yin S , Buono SA , Dasu T , Bhattacharyya S , Westergaard RP , Pray IW , Ye D , Nabity SA , Tate JE , Kirking HL . medRxiv 2020 2020.05.13.20101006 Olfactory and taste dysfunctions have emerged as symptoms of COVID-19. Among individuals with COVID-19 enrolled in a household study, loss of taste and/or smell was the fourth most commonly reported symptom (26/42; 62%), and among household contacts, it had the highest positive predictive value (83%; 95% CI: 55–95%) for COVID-19. These findings support consideration of loss of taste and/or smell in possible case identification and testing prioritization for COVID-19.Competing Interest StatementThe authors have declared no competing interest.Funding StatementNo external funding was received.Author DeclarationsAll relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.YesAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData presented in the current study may be available from the corresponding author on request. |
Enhanced Contact Investigations for Nine Early Travel-Related Cases of SARS-CoV-2 in the United States (preprint)
Burke RM , Balter S , Barnes E , Barry V , Bartlett K , Beer KD , Benowitz I , Biggs HM , Bruce H , Bryant-Genevier J , Cates J , Chatham-Stephens K , Chea N , Chiou H , Christiansen D , Chu VT , Clark S , Cody SH , Cohen M , Conners EE , Dasari V , Dawson P , DeSalvo T , Donahue M , Dratch A , Duca L , Duchin J , Dyal JW , Feldstein LR , Fenstersheib M , Fischer M , Fisher R , Foo C , Freeman-Ponder B , Fry AM , Gant J , Gautom R , Ghinai I , Gounder P , Grigg CT , Gunzenhauser J , Hall AJ , Han GS , Haupt T , Holshue M , Hunter J , Ibrahim MB , Jacobs MW , Jarashow MC , Joshi K , Kamali T , Kawakami V , Kim M , Kirking HL , Kita-Yarbro A , Klos R , Kobayashi M , Kocharian A , Lang M , Layden J , Leidman E , Lindquist S , Lindstrom S , Link-Gelles R , Marlow M , Mattison CP , McClung N , McPherson TD , Mello L , Midgley CM , Novosad S , Patel MT , Pettrone K , Pillai SK , Pray IW , Reese HE , Rhodes H , Robinson S , Rolfes M , Routh J , Rubin R , Rudman SL , Russell D , Scott S , Shetty V , Smith-Jeffcoat SE , Soda EA , Spitters C , Stierman B , Sunenshine R , Terashita D , Traub E , Vahey GM , Verani JR , Wallace M , Westercamp M , Wortham J , Xie A , Yousaf A , Zahn M . medRxiv 2020 2020.04.27.20081901 Background Coronavirus disease 2019 (COVID-19), the respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and has since become pandemic. As part of initial response activities in the United States, enhanced contact investigations were conducted to enable early identification and isolation of additional cases and to learn more about risk factors for transmission.Methods Close contacts of nine early travel-related cases in the United States were identified. Close contacts meeting criteria for active monitoring were followed, and selected individuals were targeted for collection of additional exposure details and respiratory samples. Respiratory samples were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (RT-PCR) at the Centers for Disease Control and Prevention.Results There were 404 close contacts who underwent active monitoring in the response jurisdictions; 338 had at least basic exposure data, of whom 159 had ≥1 set of respiratory samples collected and tested. Across all known close contacts under monitoring, two additional cases were identified; both secondary cases were in spouses of travel-associated case patients. The secondary attack rate among household members, all of whom had ≥1 respiratory sample tested, was 13% (95% CI: 4 – 38%).Conclusions The enhanced contact tracing investigations undertaken around nine early travel-related cases of COVID-19 in the United States identified two cases of secondary transmission, both spouses. Rapid detection and isolation of the travel-associated case patients, enabled by public awareness of COVID-19 among travelers from China, may have mitigated transmission risk among close contacts of these cases.Competing Interest StatementThe authors have declared no competing interest.Funding StatementNo external funding was sought or received.Author DeclarationsAll relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.YesAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesData may be available upon reasonable request. |
Tracing the origin of SARS-CoV-2 Omicron-like Spike sequences detected in wastewater (preprint)
Shafer MM , Bobholz MJ , Vuyk WC , Gregory D , Roguet A , Haddock Soto LA , Rushford C , Janssen KH , Ries HJ , Pilch HE , Mullen PA , Fahney RB , Wei W , Lambert M , Wenzel J , Halfmann P , Kawaoka Y , Wilson NA , Friedrich TC , Pray IW , Westergaard R , O'Connor DH , Johnson MC . medRxiv 2022 31 Background: The origin of divergent SARS-CoV-2 spike sequences found in wastewater, but not in clinical surveillance, remains unclear. These "cryptic" wastewater sequences have harbored many of the same mutations that later emerged in Omicron lineages. We first detected a cryptic lineage in municipal wastewater in Wisconsin in January 2022. Named the "Wisconsin Lineage", we sought to determine this virus's geographic origin and characterize its persistence and evolution over time. Method(s): We systematically sampled maintenance holes to trace the Wisconsin Lineage's origin. We sequenced spike RBD domains, and where possible, whole viral genomes, to characterize the evolution of this lineage over the 13 consecutive months that it was detectable. Finding(s): The persistence of the Wisconsin Lineage signal allowed us to trace it from a central wastewater plant to a single facility, with a high concentration of viral RNA. The viral sequences contained a combination of fixed nucleotide substitutions characteristic of Pango lineage B.1.234, which circulated in Wisconsin at low levels from October 2020 to February 2021, while mutations in the spike gene resembled those subsequently found in Omicron variants. Interpretation(s): We propose that prolonged detection of the Wisconsin Lineage in wastewater represents persistent shedding of SARS-CoV-2 from an infected individual, with ongoing within-host viral evolution leading to an ancestral B.1.234 virus accumulating "Omicron-like" mutations. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license. |
SARS-CoV-2 transmission in intercollegiate athletics not fully mitigated with daily antigen testing (preprint)
Moreno GK , Braun KM , Pray IW , Segaloff HE , Lim A , Poulson K , Meiman J , Borcher J , Westergaard RP , Moll MK , Friedrich TC , O'Connor DH . medRxiv 2021 BACKGROUND: High frequency, rapid turnaround SARS-CoV-2 testing continues to be proposed as a way of efficiently identifying and mitigating transmission in congregate settings. However, two SARS-CoV-2 outbreaks occurred among intercollegiate university athletic programs during the fall 2020 semester despite mandatory directly observed daily antigen testing. METHODS: During the fall 2020 semester, athletes and staff in both programs were tested daily using Quidel's Sofia SARS Antigen Fluorescent Immunoassay (FIA), with positive antigen results requiring confirmatory testing with real-time reverse transcription polymerase chain reaction (RT-PCR). We used genomic sequencing to investigate transmission dynamics in these two outbreaks. RESULTS: In Outbreak 1, 32 confirmed cases occurred within a university athletics program after the index patient attended a meeting while infectious despite a negative antigen test on the day of the meeting. Among isolates sequenced from Outbreak 1, 24 (92%) of 26 were closely related, suggesting sustained transmission following an initial introduction event. In Outbreak 2, 12 confirmed cases occurred among athletes from two university programs that faced each other in an athletic competition despite receiving negative antigen test results on the day of the competition. Sequences from both teams were closely related and unique from strains circulating in the community, suggesting transmission during intercollegiate competition. CONCLUSIONS: These findings suggest that antigen testing alone, even when mandated and directly observed, may not be sufficient as an intervention to prevent SARS-CoV-2 outbreaks in congregate settings, and highlights the importance of supplementing serial antigen testing with appropriate mitigation strategies to prevent SARS-CoV-2 outbreak in congregate settings. SUMMARY: High frequency, rapid turnaround SARS-CoV-2 testing continues to be proposed as a way of efficiently identifying and mitigating transmission in congregate settings. However, here we describe two SARS-CoV-2 outbreaks occurred among intercollegiate university athletic programs during the fall 2020 semester. |
School District Prevention Policies and Risk of COVID-19 Among In-Person K-12 Educators, Wisconsin, 2021.
DeJonge PM , Pray IW , Gangnon R , McCoy K , Tomasallo C , Meiman J . Am J Public Health 2022 112 (12) 1791-1799 Objectives. To assess the rate of COVID-19 among in-person K-12 educators and the rate's association with various COVID-19 prevention policies in school districts. Methods. We linked actively working, in-person K-12 educators in Wisconsin to COVID-19 cases with onset from September 2 to November 24, 2021. A mixed-effects Cox proportional hazards model, adjusted for pertinent person- and community-level confounders, compared the hazard rate of COVID-19 among educators working in districts with and without specific COVID-19 prevention policies. Results. In-person educators working in school districts that required masking for students and staff experienced 19% lower hazards of COVID-19 than did those in districts without any masking policy (hazard ratio = 0.81; 95% confidence interval = 0.72, 0.92). Reduced COVID-19 hazards were consistent and remained statistically significant when educators were stratified by elementary, middle, and high school environments. Conclusions. In Wisconsin's K-12 school districts, during the fall 2021 academic semester, a policy that required both students and staff to mask was associated with significantly reduced risk of COVID-19 among in-person educators across all grade levels. (Am J Public Health. 2022;112(12):1791-1799. https://doi.org/10.2105/AJPH.2022.307095). |
Measuring work-related risk of COVID-19: comparison of COVID-19 incidence by occupation and industry - Wisconsin, September 2020-May 2021.
Pray IW , Grajewski B , Morris C , Modji K , DeJonge P , McCoy K , Tomasallo C , DeSalvo T , Westergaard RP , Meiman J . Clin Infect Dis 2022 76 (3) e163-e171 BACKGROUND: Work-related exposures play an important role in SARS-CoV-2 transmission, yet few studies have measured the risk of COVID-19 across occupations and industries. METHODS: During September 2020 - May 2021, the Wisconsin Department of Health Services collected occupation and industry data as part of routine COVID-19 case investigations. Adults aged 18-64 years with confirmed or probable COVID-19 in Wisconsin were assigned standardized occupation and industry codes. Cumulative incidence rates were weighted for non-response and calculated using full-time equivalent (FTE) workforce denominators from the 2020 American Community Survey. RESULTS: An estimated 11.6% of workers (347,013 of 2.98 million) in Wisconsin, ages 18-64 years, had COVID-19 from September 2020 to May 2021. The highest incidence by occupation (per 100 full-time equivalents) occurred among personal care and services workers (22.4), healthcare practitioners and support staff (20.7), and protective services workers (20.7). High risk sub-groups included nursing assistants and personal care aides (28.8), childcare workers (25.8), food and beverage service workers (25.3), personal appearance workers (24.4), and law enforcement workers (24.1). By industry, incidence was highest in healthcare (18.6); the highest risk sub-sectors were nursing care facilities (30.5) and warehousing (28.5). CONCLUSIONS: This analysis represents one of the most complete examinations to date of COVID-19 incidence by occupation and industry. Our approach demonstrates the value of standardized occupational data collection by public health, and may be a model for improved occupational surveillance elsewhere. Workers at higher risk of SARS-CoV-2 exposure may benefit from targeted workplace COVID-19 vaccination and mitigation efforts. |
Public health actions to control measles among Afghan evacuees during Operation Allies Welcome - United States, September-November 2021
Masters NB , Mathis AD , Leung J , Raines K , Clemmons NS , Miele K , Balajee SA , Lanzieri TM , Marin M , Christensen DL , Clarke KR , Cruz MA , Gallagher K , Gearhart S , Gertz AM , Grady-Erickson O , Habrun CA , Kim G , Kinzer MH , Miko S , Oberste MS , Petras JK , Pieracci EG , Pray IW , Rosenblum HG , Ross JM , Rothney EE , Segaloff HE , Shepersky LV , Skrobarcek KA , Stadelman AM , Sumner KM , Waltenburg MA , Weinberg M , Worrell MC , Bessette NE , Peake LR , Vogt MP , Robinson M , Westergaard RP , Griesser RH , Icenogle JP , Crooke SN , Bankamp B , Stanley SE , Friedrichs PA , Fletcher LD , Zapata IA , Wolfe HO , Gandhi PH , Charles JY , Brown CM , Cetron MS , Pesik N , Knight NW , Alvarado-Ramy F , Bell M , Talley LE , Rotz LD , Rota PA , Sugerman DE , Gastañaduy PA . MMWR Morb Mortal Wkly Rep 2022 71 (17) 592-596 On August 29, 2021, the United States government oversaw the emergent establishment of Operation Allies Welcome (OAW), led by the U.S. Department of Homeland Security (DHS) and implemented by the U.S. Department of Defense (DoD) and U.S. Department of State (DoS), to safely resettle U.S. citizens and Afghan nationals from Afghanistan to the United States. Evacuees were temporarily housed at several overseas locations in Europe and Asia* before being transported via military and charter flights through two U.S. international airports, and onward to eight U.S. military bases,(†) with hotel A used for isolation and quarantine of persons with or exposed to certain infectious diseases.(§) On August 30, CDC issued an Epi-X notice encouraging public health officials to maintain vigilance for measles among Afghan evacuees because of an ongoing measles outbreak in Afghanistan (25,988 clinical cases reported nationwide during January-November 2021) (1) and low routine measles vaccination coverage (66% and 43% for the first and second doses, respectively, in 2020) (2). |
Interventions to Disrupt Coronavirus Disease Transmission at a University, Wisconsin, USA, August-October 2020.
Currie DW , Moreno GK , Delahoy MJ , Pray IW , Jovaag A , Braun KM , Cole D , Shechter T , Fajardo GC , Griggs C , Yandell BS , Goldstein S , Bushman D , Segaloff HE , Kelly GP , Pitts C , Lee C , Grande KM , Kita-Yarbro A , Grogan B , Mader S , Baggott J , Bateman AC , Westergaard RP , Tate JE , Friedrich TC , Kirking HL , O'Connor DH , Killerby ME . Emerg Infect Dis 2021 27 (11) 2776-2785 University settings have demonstrated potential for coronavirus disease (COVID-19) outbreaks; they combine congregate living, substantial social activity, and a young population predisposed to mild illness. Using genomic and epidemiologic data, we describe a COVID-19 outbreak at the University of Wisconsin-Madison, Madison, Wisconsin, USA. During August-October 2020, a total of 3,485 students, including 856/6,162 students living in dormitories, tested positive. Case counts began rising during move-in week, August 25-31, 2020, then rose rapidly during September 1-11, 2020. The university initiated multiple prevention efforts, including quarantining 2 dormitories; a subsequent decline in cases was observed. Genomic surveillance of cases from Dane County, in which the university is located, did not find evidence of transmission from a large cluster of cases in the 2 quarantined dorms during the outbreak. Coordinated implementation of prevention measures can reduce COVID-19 spread in university settings and may limit spillover to the surrounding community. |
Severe Acute Respiratory Syndrome Coronavirus 2 Transmission in Intercollegiate Athletics Not Fully Mitigated With Daily Antigen Testing.
Moreno GK , Braun KM , Pray IW , Segaloff HE , Lim A , Poulsen K , Meiman J , Borcher J , Westergaard RP , Moll MK , Friedrich TC , O'Connor DH . Clin Infect Dis 2021 73 S45-S53 BACKGROUND: High-frequency, rapid-turnaround SARS-CoV-2 testing continues to be proposed as a way of efficiently identifying and mitigating transmission in congregate settings. However, two SARS-CoV-2 outbreaks occurred among intercollegiate university athletic programs during the fall 2020 semester despite mandatory directly observed daily antigen testing. METHODS: During the fall 2020 semester, athletes and staff in both programs were tested daily using Quidel's Sofia SARS Antigen Fluorescent Immunoassay (FIA), with positive antigen results requiring confirmatory testing with real-time reverse transcription polymerase chain reaction (RT-PCR). We used genomic sequencing to investigate transmission dynamics in these two outbreaks. RESULTS: In Outbreak 1, 32 confirmed cases occurred within a university athletics program after the index patient attended a meeting while infectious despite a negative antigen test on the day of the meeting. Among isolates sequenced from Outbreak 1, 24 (92%) of 26 were closely related, suggesting sustained transmission following an initial introduction event. In Outbreak 2, 12 confirmed cases occurred among athletes from two university programs that faced each other in an athletic competition despite receiving negative antigen test results on the day of the competition. Sequences from both teams were closely related and distinct from viruses circulating in Team 1's community, suggesting transmission during intercollegiate competition in Team 2's community. CONCLUSIONS: These findings suggest that antigen testing alone, even when mandated and directly observed, may not be sufficient as an intervention to prevent SARS-CoV-2 outbreaks in congregate settings, and highlight the importance of supplementing serial antigen testing with appropriate mitigation strategies to prevent SARS-CoV-2 outbreak in congregate settings. |
Epidemiologic characteristics associated with SARS-CoV-2 antigen-based test results, rRT-PCR cycle threshold values, subgenomic RNA, and viral culture results from university testing.
Ford L , Lee C , Pray IW , Cole D , Bigouette JP , Abedi GR , Bushman D , Delahoy MJ , Currie DW , Cherney B , Kirby M , Fajardo G , Caudill M , Langolf K , Kahrs J , Zochert T , Kelly P , Pitts C , Lim A , Aulik N , Tamin A , Harcourt JL , Queen K , Zhang J , Whitaker B , Browne H , Medrzycki M , Shewmaker P , Bonenfant G , Zhou B , Folster J , Bankamp B , Bowen MD , Thornburg NJ , Goffard K , Limbago B , Bateman A , Tate JE , Gieryn D , Kirking HL , Westergaard R , Killerby M . Clin Infect Dis 2021 73 (6) e1348-e1355 BACKGROUND: Real-time reverse transcription polymerase chain reaction (rRT-PCR) and antigen tests are important diagnostics for SARS-CoV-2. Sensitivity of antigen tests has been shown to be lower than that of rRT-PCR; however, data to evaluate epidemiologic characteristics that affect test performance are limited. METHODS: Paired mid-turbinate nasal swabs were collected from university students and staff and tested for SARS-CoV-2 using both Quidel Sofia SARS Antigen Fluorescent Immunoassay (FIA) and rRT-PCR assay. Specimens positive by either rRT-PCR or antigen FIA were placed in viral culture and tested for subgenomic RNA (sgRNA). Logistic regression models were used to evaluate characteristics associated with antigen results, rRT-PCR cycle threshold (Ct) values, sgRNA, and viral culture. RESULTS: Antigen FIA sensitivity was 78.9% and 43.8% among symptomatic and asymptomatic participants respectively. Among rRT-PCR positive participants, negative antigen results were more likely among asymptomatic participants (OR 4.6, CI:1.3-15.4) and less likely among participants reporting nasal congestion (OR 0.1, CI:0.03-0.8). rRT-PCR-positive specimens with higher Ct values (OR 0.5, CI:0.4-0.8) were less likely, and specimens positive for sgRNA (OR 10.2, CI:1.6-65.0) more likely, to yield positive virus isolation. Antigen testing was >90% positive in specimens with Ct values <29. Positive predictive value of antigen test for positive viral culture (57.7%) was similar to that of rRT-PCR (59.3%). CONCLUSIONS: SARS-CoV-2 antigen test advantages include low cost, wide availability and rapid turnaround time, making them important screening tests. The performance of antigen tests may vary with patient characteristics, so performance characteristics should be accounted for when designing testing strategies and interpreting results. |
Persistent SARS-CoV-2 RNA Shedding without Evidence of Infectiousness: A Cohort Study of Individuals with COVID-19.
Owusu D , Pomeroy MA , Lewis NM , Wadhwa A , Yousaf AR , Whitaker B , Dietrich E , Hall AJ , Chu V , Thornburg N , Christensen K , Kiphibane T , Willardson S , Westergaard R , Dasu T , Pray IW , Bhattacharyya S , Dunn A , Tate JE , Kirking HL , Matanock A . J Infect Dis 2021 224 (8) 1362-1371 BACKGROUND: To better understand SARS-CoV-2 shedding duration and infectivity, we estimated SARS-CoV-2 RNA shedding duration, described characteristics associated with viral RNA shedding resolution1, and determined if replication-competent viruses could be recovered ≥10 days after symptom onset among individuals with mild to moderate COVID-19. METHODS: We collected serial nasopharyngeal specimens at various time points from 109 individuals with rRT-PCR-confirmed COVID-19 in Utah and Wisconsin. We calculated probability of viral RNA shedding resolution using the Kaplan-Meier estimator and evaluated characteristics associated with shedding resolution using Cox proportional hazards regression. We attempted viral culture for 35 rRT-PCR-positive nasopharyngeal specimens collected ≥10 days after symptom onset. RESULTS: The likelihood of viral RNA shedding resolution at 10 days after symptom onset was approximately 3%. Time to shedding resolution was shorter among participants aged <18 years (adjusted hazards ratio [aHR]: 3.01; 95% CI: 1.6-5.6) and longer among those aged ≥50 years (aHR: 0.50; 95% CI: 0.3-0.9) compared to participants aged 18-49 years. No replication-competent viruses were recovered. CONCLUSIONS: Although most patients were positive for SARS-CoV-2 for ≥10 days after symptom onset, our findings suggest that individuals with mild to moderate COVID-19 are unlikely to be infectious ≥10 days after symptom onset. |
Trends in Outbreak-Associated Cases of COVID-19 - Wisconsin, March-November 2020.
Pray IW , Kocharian A , Mason J , Westergaard R , Meiman J . MMWR Morb Mortal Wkly Rep 2021 70 (4) 114-117 During September 3-November 16, 2020, daily confirmed cases of coronavirus disease 2019 (COVID-19) reported to the Wisconsin Department of Health Services (WDHS) increased at a rate of 24% per week, from a 7-day average of 674 (August 28-September 3) to 6,426 (November 10-16) (1). The growth rate during this interval was the highest to date in Wisconsin and among the highest in the United States during that time (1). To characterize potential sources of this increase, the investigation examined reported outbreaks in Wisconsin that occurred during March 4-November 16, 2020, with respect to their setting and number of associated COVID-19 cases. |
Performance of an Antigen-Based Test for Asymptomatic and Symptomatic SARS-CoV-2 Testing at Two University Campuses - Wisconsin, September-October 2020.
Pray IW , Ford L , Cole D , Lee C , Bigouette JP , Abedi GR , Bushman D , Delahoy MJ , Currie D , Cherney B , Kirby M , Fajardo G , Caudill M , Langolf K , Kahrs J , Kelly P , Pitts C , Lim A , Aulik N , Tamin A , Harcourt JL , Queen K , Zhang J , Whitaker B , Browne H , Medrzycki M , Shewmaker P , Folster J , Bankamp B , Bowen MD , Thornburg NJ , Goffard K , Limbago B , Bateman A , Tate JE , Gieryn D , Kirking HL , Westergaard R , Killerby M . MMWR Morb Mortal Wkly Rep 2021 69 (5152) 1642-1647 Antigen-based tests for SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), are inexpensive and can return results within 15 minutes (1). Antigen tests have received Food and Drug Administration (FDA) Emergency Use Authorization (EUA) for use in asymptomatic and symptomatic persons within the first 5-12 days after symptom onset (2). These tests have been used at U.S. colleges and universities and other congregate settings (e.g., nursing homes and correctional and detention facilities), where serial testing of asymptomatic persons might facilitate early case identification (3-5). However, test performance data from symptomatic and asymptomatic persons are limited. This investigation evaluated performance of the Sofia SARS Antigen Fluorescent Immunoassay (FIA) (Quidel Corporation) compared with real-time reverse transcription-polymerase chain reaction (RT-PCR) for SARS-CoV-2 detection among asymptomatic and symptomatic persons at two universities in Wisconsin. During September 28-October 9, a total of 1,098 paired nasal swabs were tested using the Sofia SARS Antigen FIA and real-time RT-PCR. Virus culture was attempted on all antigen-positive or real-time RT-PCR-positive specimens. Among 871 (79%) paired swabs from asymptomatic participants, the antigen test sensitivity was 41.2%, specificity was 98.4%, and in this population the estimated positive predictive value (PPV) was 33.3%, and negative predictive value (NPV) was 98.8%. Antigen test performance was improved among 227 (21%) paired swabs from participants who reported one or more symptoms at specimen collection (sensitivity = 80.0%; specificity = 98.9%; PPV = 94.1%; NPV = 95.9%). Virus was isolated from 34 (46.6%) of 73 antigen-positive or real-time RT-PCR-positive nasal swab specimens, including two of 18 that were antigen-negative and real-time RT-PCR-positive (false-negatives). The advantages of antigen tests such as low cost and rapid turnaround might allow for rapid identification of infectious persons. However, these advantages need to be balanced against lower sensitivity and lower PPV, especially among asymptomatic persons. Confirmatory testing with an FDA-authorized nucleic acid amplification test (NAAT), such as RT-PCR, should be considered after negative antigen test results in symptomatic persons, and after positive antigen test results in asymptomatic persons (1). |
Household Transmission of SARS-CoV-2 in the United States.
Lewis NM , Chu VT , Ye D , Conners EE , Gharpure R , Laws RL , Reses HE , Freeman BD , Fajans M , Rabold EM , Dawson P , Buono S , Yin S , Owusu D , Wadhwa A , Pomeroy M , Yousaf A , Pevzner E , Njuguna H , Battey KA , Tran CH , Fields VL , Salvatore P , O'Hegarty M , Vuong J , Chancey R , Gregory C , Banks M , Rispens JR , Dietrich E , Marcenac P , Matanock AM , Duca L , Binder A , Fox G , Lester S , Mills L , Gerber SI , Watson J , Schumacher A , Pawloski L , Thornburg NJ , Hall AJ , Kiphibane T , Willardson S , Christensen K , Page L , Bhattacharyya S , Dasu T , Christiansen A , Pray IW , Westergaard RP , Dunn AC , Tate JE , Nabity SA , Kirking HL . Clin Infect Dis 2020 73 (7) 1805-1813 BACKGROUND: Although many viral respiratory illnesses are transmitted within households, the evidence base for SARS-CoV-2 is nascent. We sought to characterize SARS-CoV-2 transmission within US households and estimate the household secondary infection rate (SIR) to inform strategies to reduce transmission. METHODS: We recruited laboratory-confirmed COVID-19 patients and their household contacts in Utah and Wisconsin during March 22-April 25, 2020. We interviewed patients and all household contacts to obtain demographics and medical histories. At the initial household visit, 14 days later, and when a household contact became newly symptomatic, we collected respiratory swabs from patients and household contacts for testing by SARS-CoV-2 rRT-PCR and sera for SARS-CoV-2 antibodies testing by enzyme-linked immunosorbent assay (ELISA). We estimated SIR and odds ratios (OR) to assess risk factors for secondary infection, defined by a positive rRT-PCR or ELISA test. RESULTS: Thirty-two (55%) of 58 households had evidence of secondary infection among household contacts. The SIR was 29% (n = 55/188; 95% confidence interval [CI]: 23-36%) overall, 42% among children (<18 years) of the COVID-19 patient and 33% among spouses/partners. Household contacts to COVID-19 patients with immunocompromised conditions had increased odds of infection (OR: 15.9, 95% CI: 2.4-106.9). Household contacts who themselves had diabetes mellitus had increased odds of infection (OR: 7.1, 95% CI: 1.2-42.5). CONCLUSIONS: We found substantial evidence of secondary infections among household contacts. People with COVID-19, particularly those with immunocompromising conditions or those with household contacts with diabetes, should take care to promptly self-isolate to prevent household transmission. |
Coronavirus Disease among Workers in Food Processing, Food Manufacturing, and Agriculture Workplaces.
Waltenburg MA , Rose CE , Victoroff T , Butterfield M , Dillaha JA , Heinzerling A , Chuey M , Fierro M , Jervis RH , Fedak KM , Leapley A , Gabel JA , Feldpausch A , Dunne EM , Austin C , Pedati CS , Ahmed FS , Tubach S , Rhea C , Tonzel J , Krueger A , Crum DA , Vostok J , Moore MJ , Kempher H , Scheftel J , Turabelidze G , Stover D , Donahue M , Thomas D , Edge K , Gutierrez B , Berl E , McLafferty M , Kline KE , Martz N , Rajotte JC , Julian E , Diedhiou A , Radcliffe R , Clayton JL , Ortbahn D , Cummins J , Barbeau B , Carpenter S , Pringle JC , Murphy J , Darby B , Graff NR , Dostal TKH , Pray IW , Tillman C , Rose DA , Honein MA . Emerg Infect Dis 2020 27 (1) 243-9 We describe coronavirus disease (COVID-19) among US food manufacturing and agriculture workers and provide updated information on meat and poultry processing workers. Among 742 food and agriculture workplaces in 30 states, 8,978 workers had confirmed COVID-19; 55 workers died. Racial and ethnic minority workers could be disproportionately affected by COVID-19. |
COVID-19 Outbreak at an Overnight Summer School Retreat - Wisconsin, July-August 2020.
Pray IW , Gibbons-Burgener SN , Rosenberg AZ , Cole D , Borenstein S , Bateman A , Pevzner E , Westergaard RP . MMWR Morb Mortal Wkly Rep 2020 69 (43) 1600-1604 During July 2-August 11, 2020, an outbreak of coronavirus disease 2019 (COVID-19) occurred at a boys' overnight summer school retreat in Wisconsin. The retreat included 152 high school-aged boys, counselors, and staff members from 21 states and territories and two foreign countries. All attendees were required to provide documentation of either a positive serologic test result* within the past 3 months or a negative reverse transcription-polymerase chain reaction (RT-PCR) tests result for SARS-CoV-2 (the virus that causes COVID-19) ≤7 days before travel, to self-quarantine within their households for 7 days before travel, and to wear masks during travel. On July 15, the Wisconsin Department of Health Services (WDHS) began an investigation after being notified that two students at the retreat had received positive SARS-CoV-2 RT-PCR test results. WDHS offered RT-PCR testing to attendees on July 28 and serologic testing on August 5 and 6. Seventy-eight (51%) attendees received positive RT-PCR results (confirmed cases), and 38 (25%) met clinical criteria for COVID-19 without a positive RT-PCR result (probable cases). By the end of the retreat, 118 (78%) persons had received a positive serologic test result. Among 24 attendees with a documented positive serologic test result before the retreat, all received negative RT-PCR results. After RT-PCR testing on July 28, WDHS recommended that remaining susceptible persons (asymptomatic and with negative RT-PCR test results) quarantine from other students and staff members at the retreat. Recommended end dates for isolation or quarantine were based on established guidance (1,2) and determined in coordination with CDC. All attendees were cleared for interstate and commercial air travel to return home on August 11. This outbreak investigation documented rapid spread of SARS-CoV-2, likely from a single student, among adolescents and young adults in a congregate setting. Mitigation plans that include prearrival quarantine and testing, cohorting, symptom monitoring, early identification and isolation of cases, mask use, enhanced hygiene and disinfection practices, and maximal outdoor programming are necessary to prevent COVID-19 outbreaks in these settings (3,4). |
Enhanced contact investigations for nine early travel-related cases of SARS-CoV-2 in the United States.
Burke RM , Balter S , Barnes E , Barry V , Bartlett K , Beer KD , Benowitz I , Biggs HM , Bruce H , Bryant-Genevier J , Cates J , Chatham-Stephens K , Chea N , Chiou H , Christiansen D , Chu VT , Clark S , Cody SH , Cohen M , Conners EE , Dasari V , Dawson P , DeSalvo T , Donahue M , Dratch A , Duca L , Duchin J , Dyal JW , Feldstein LR , Fenstersheib M , Fischer M , Fisher R , Foo C , Freeman-Ponder B , Fry AM , Gant J , Gautom R , Ghinai I , Gounder P , Grigg CT , Gunzenhauser J , Hall AJ , Han GS , Haupt T , Holshue M , Hunter J , Ibrahim MB , Jacobs MW , Jarashow MC , Joshi K , Kamali T , Kawakami V , Kim M , Kirking HL , Kita-Yarbro A , Klos R , Kobayashi M , Kocharian A , Lang M , Layden J , Leidman E , Lindquist S , Lindstrom S , Link-Gelles R , Marlow M , Mattison CP , McClung N , McPherson TD , Mello L , Midgley CM , Novosad S , Patel MT , Pettrone K , Pillai SK , Pray IW , Reese HE , Rhodes H , Robinson S , Rolfes M , Routh J , Rubin R , Rudman SL , Russell D , Scott S , Shetty V , Smith-Jeffcoat SE , Soda EA , Spitters C , Stierman B , Sunenshine R , Terashita D , Traub E , Vahey GM , Verani JR , Wallace M , Westercamp M , Wortham J , Xie A , Yousaf A , Zahn M . PLoS One 2020 15 (9) e0238342 Coronavirus disease 2019 (COVID-19), the respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and has since become pandemic. In response to the first cases identified in the United States, close contacts of confirmed COVID-19 cases were investigated to enable early identification and isolation of additional cases and to learn more about risk factors for transmission. Close contacts of nine early travel-related cases in the United States were identified and monitored daily for development of symptoms (active monitoring). Selected close contacts (including those with exposures categorized as higher risk) were targeted for collection of additional exposure information and respiratory samples. Respiratory samples were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction at the Centers for Disease Control and Prevention. Four hundred four close contacts were actively monitored in the jurisdictions that managed the travel-related cases. Three hundred thirty-eight of the 404 close contacts provided at least basic exposure information, of whom 159 close contacts had ≥1 set of respiratory samples collected and tested. Across all actively monitored close contacts, two additional symptomatic COVID-19 cases (i.e., secondary cases) were identified; both secondary cases were in spouses of travel-associated case patients. When considering only household members, all of whom had ≥1 respiratory sample tested for SARS-CoV-2, the secondary attack rate (i.e., the number of secondary cases as a proportion of total close contacts) was 13% (95% CI: 4-38%). The results from these contact tracing investigations suggest that household members, especially significant others, of COVID-19 cases are at highest risk of becoming infected. The importance of personal protective equipment for healthcare workers is also underlined. Isolation of persons with COVID-19, in combination with quarantine of exposed close contacts and practice of everyday preventive behaviors, is important to mitigate spread of COVID-19. |
Update: COVID-19 Among Workers in Meat and Poultry Processing Facilities - United States, April-May 2020.
Waltenburg MA , Victoroff T , Rose CE , Butterfield M , Jervis RH , Fedak KM , Gabel JA , Feldpausch A , Dunne EM , Austin C , Ahmed FS , Tubach S , Rhea C , Krueger A , Crum DA , Vostok J , Moore MJ , Turabelidze G , Stover D , Donahue M , Edge K , Gutierrez B , Kline KE , Martz N , Rajotte JC , Julian E , Diedhiou A , Radcliffe R , Clayton JL , Ortbahn D , Cummins J , Barbeau B , Murphy J , Darby B , Graff NR , Dostal TKH , Pray IW , Tillman C , Dittrich MM , Burns-Grant G , Lee S , Spieckerman A , Iqbal K , Griffing SM , Lawson A , Mainzer HM , Bealle AE , Edding E , Arnold KE , Rodriguez T , Merkle S , Pettrone K , Schlanger K , LaBar K , Hendricks K , Lasry A , Krishnasamy V , Walke HT , Rose DA , Honein MA . MMWR Morb Mortal Wkly Rep 2020 69 (27) 887-892 Meat and poultry processing facilities face distinctive challenges in the control of infectious diseases, including coronavirus disease 2019 (COVID-19) (1). COVID-19 outbreaks among meat and poultry processing facility workers can rapidly affect large numbers of persons. Assessment of COVID-19 cases among workers in 115 meat and poultry processing facilities through April 27, 2020, documented 4,913 cases and 20 deaths reported by 19 states (1). This report provides updated aggregate data from states regarding the number of meat and poultry processing facilities affected by COVID-19, the number and demographic characteristics of affected workers, and the number of COVID-19-associated deaths among workers, as well as descriptions of interventions and prevention efforts at these facilities. Aggregate data on confirmed COVID-19 cases and deaths among workers identified and reported through May 31, 2020, were obtained from 239 affected facilities (those with a laboratory-confirmed COVID-19 case in one or more workers) in 23 states.* COVID-19 was confirmed in 16,233 workers, including 86 COVID-19-related deaths. Among 14 states reporting the total number of workers in affected meat and poultry processing facilities (112,616), COVID-19 was diagnosed in 9.1% of workers. Among 9,919 (61%) cases in 21 states with reported race/ethnicity, 87% occurred among racial and ethnic minority workers. Commonly reported interventions and prevention efforts at facilities included implementing worker temperature or symptom screening and COVID-19 education, mandating face coverings, adding hand hygiene stations, and adding physical barriers between workers. Targeted workplace interventions and prevention efforts that are appropriately tailored to the groups most affected by COVID-19 are critical to reducing both COVID-19-associated occupational risk and health disparities among vulnerable populations. Implementation of these interventions and prevention efforts(dagger) across meat and poultry processing facilities nationally could help protect workers in this critical infrastructure industry. |
Loss of Taste and Smell as Distinguishing Symptoms of Coronavirus Disease 2019.
Dawson P , Rabold EM , Laws RL , Conners EE , Gharpure R , Yin S , Buono SA , Dasu T , Bhattacharyya S , Westergaard RP , Pray IW , Ye D , Nabity SA , Tate JE , Kirking HL . Clin Infect Dis 2020 72 (4) 682-685 In a household study, loss of taste and/or smell was the fourth most reported symptom (26/42; 62%) among COVID-19 case-patients and had the highest positive predictive value (83%; 95% CI: 55-95%) among household contacts. Olfactory and taste dysfunctions should be considered for COVID-19 case identification and testing prioritization. |
E-cigarette, or vaping, product use-associated lung injury among clusters of patients reporting shared product use - Wisconsin, 2019
Pray IW , Atti SK , Tomasallo C , Meiman JG . MMWR Morb Mortal Wkly Rep 2020 69 (9) 236-240 On July 10, 2019, Wisconsin Department of Health Services (WDHS) was notified of five previously healthy adolescents with severe lung injuries who reported use of e-cigarette, or vaping, products before symptom onset. As of December 31, 2019, 105 confirmed or probable cases of e-cigarette, or vaping, product use-associated lung injury (EVALI)* had been reported to WDHS . Three social clusters (A, B, and C), comprising eight EVALI patients (cluster A = two patients, cluster B = three, and cluster C = three) were identified. WDHS investigated these clusters with standard and follow-up interviews; laboratory analysis of e-cigarette, or vaping, products; and analysis of bronchoalveolar lavage (BAL) fluid. All eight patients reported daily use of tetrahydrocannabinol (THC)-containing e-cigarette, or vaping, product cartridges (THC cartridges) in the month preceding symptom onset. All THC cartridges were purchased from local illicit dealers, and all patients reported using THC cartridges labeled as "Dank Vapes," among other illicit brand names. At least two members of each cluster reported frequent sharing of THC cartridges before symptom onset. All eight patients also reported daily use of nicotine-containing e-cigarette, or vaping, products. Vitamin E acetate (VEA) was detected in all five THC cartridges tested from two patients, and in BAL fluid from two other patients. These findings suggest that THC cartridges containing VEA and sold on the illicit market were likely responsible for these small clusters of EVALI. Based on information presented in this and previous reports (1,2) CDC recommends not using THC-containing e-cigarette, or vaping, products, especially those obtained from informal sources such as friends, family, or in-person or online dealers (1). VEA is strongly linked to the EVALI outbreak and should not be added to e-cigarette, or vaping, products (1). |
E-cigarette product use, or vaping, among persons with associated lung injury - Illinois and Wisconsin, April-September 2019
Ghinai I , Pray IW , Navon L , O'Laughlin K , Saathoff-Huber L , Hoots B , Kimball A , Tenforde MW , Chevinsky JR , Layer M , Ezike N , Meiman J , Layden JE . MMWR Morb Mortal Wkly Rep 2019 68 (39) 865-869 In July 2019, the Illinois Department of Public Health and the Wisconsin Department of Health Services launched a coordinated epidemiologic investigation after receiving reports of several cases of lung injury in previously healthy persons who reported electronic cigarette (e-cigarette) use, or vaping (1). This report describes features of e-cigarette product use by patients in Illinois and Wisconsin. Detailed patient interviews were conducted by telephone, in person, or via the Internet with 86 (68%) of 127 patients. Overall, 75 (87%) of 86 interviewed patients reported using e-cigarette products containing tetrahydrocannabinol (THC), and 61 (71%) reported using nicotine-containing products. Numerous products and brand names were identified by patients. Nearly all (96%) THC-containing products reported were packaged, prefilled cartridges, and 89% were primarily acquired from informal sources (e.g., friends, family members, illicit dealers, or off the street). In contrast, 77% of nicotine-containing products were sold as prefilled cartridges, and 83% were obtained from commercial vendors. The precise source of this outbreak is currently unknown (2); however, the predominant use of prefilled THC-containing cartridges among patients with lung injury associated with e-cigarette use suggests that they play an important role. While this investigation is ongoing, CDC recommends that persons consider refraining from using e-cigarette, or vaping, products, particularly those containing THC. Given the diversity of products reported and frequency of patients using both THC- and nicotine-containing e-cigarette products, additional methods such as product testing and traceback could help identify the specific cause of this outbreak. |
Characteristics of a multistate outbreak of lung injury associated with e-cigarette use, or vaping - United States, 2019
Perrine CG , Pickens CM , Boehmer TK , King BA , Jones CM , DeSisto CL , Duca LM , Lekiachvili A , Kenemer B , Shamout M , Landen MG , Lynfield R , Ghinai I , Heinzerling A , Lewis N , Pray IW , Tanz LJ , Patel A , Briss PA . MMWR Morb Mortal Wkly Rep 2019 68 (39) 860-864 Electronic cigarettes (e-cigarettes), also called vapes, e-hookas, vape pens, tank systems, mods, and electronic nicotine delivery systems (ENDS), are electronic devices that produce an aerosol by heating a liquid typically containing nicotine, flavorings, and other additives; users inhale this aerosol into their lungs (1). E-cigarettes also can be used to deliver tetrahydrocannabinol (THC), the principal psychoactive component of cannabis (1). Use of e-cigarettes is commonly called vaping. Lung injury associated with e-cigarette use, or vaping, has recently been reported in most states (2-4). CDC, the Food and Drug Administration (FDA), state and local health departments, and others are investigating this outbreak. This report provides data on patterns of the outbreak and characteristics of patients, including sex, age, and selected substances used in e-cigarette, or vaping, products reported to CDC as part of this ongoing multistate investigation. As of September 24, 2019, 46 state health departments and one territorial health department had reported 805 patients with cases of lung injury associated with use of e-cigarette, or vaping, products to CDC. Sixty-nine percent of patients were males, and the median age was 23 years (range = 13-72 years). To date, 12 deaths have been confirmed in 10 states. Among 514 patients with information on substances used in e-cigarettes, or vaping products, in the 30 days preceding symptom onset, 76.9% reported using THC-containing products, and 56.8% reported using nicotine-containing products; 36.0% reported exclusive use of THC-containing products, and 16.0% reported exclusive use of nicotine-containing products. The specific chemical exposure(s) causing the outbreak is currently unknown. While this investigation is ongoing, CDC recommends that persons consider refraining from using e-cigarette, or vaping, products, particularly those containing THC. CDC will continue to work in collaboration with FDA and state and local partners to investigate cases and advise and alert the public on the investigation as additional information becomes available. |
Clustering of necropsy-confirmed porcine cysticercosis surrounding Taenia solium tapeworm carriers in Peru
Lescano AG , Pray IW , Gonzalez AE , Gilman RH , Tsang VCW , Gamboa R , Guezala MC , Aybar V , Rodriguez S , Moulton LH , Leontsini E , Gonzalvez G , O'Neal SE , Garcia HH . Am J Trop Med Hyg 2018 100 (2) 314-322 The pork tapeworm, Taenia solium, is among the leading causes of preventable epilepsy in the world and is common in rural areas of developing countries where sanitation is limited and pigs have access to human feces. Prior studies in rural villages of Peru have observed clusters of T. solium cysticercosis among pigs that live near human tapeworm carriers. Such spatial analyses, however, have been limited by incomplete participation and substandard diagnostic tests. In this study, we evaluated the association between necropsy-confirmed cysticercosis in pigs and their distance to T. solium tapeworm carriers in six villages in northern Peru. A total of six (1.4%) tapeworm carriers were detected using enzyme-linked immunosorbent assay-coproantigen assay, and seven of 10 (70%) pigs belonging to the tapeworm carriers were found with viable cyst infection on necropsy. This was significantly greater than the prevalence of viable cyst infection among pigs living < 500 m (11%) and > 500 m (0.5%) from a tapeworm carrier (P < 0.001 for distance trend). Similar statistically significant prevalence gradients were observed after adjustment for possible confounders and for other pig-level outcomes including infection with > 10 viable cysts, degenerated cyst infection, and serological outcomes. This investigation confirms that porcine cysticercosis clusters strongly around tapeworm carriers in endemic rural regions of northern Peru and supports interventions that target these hot spots. |
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