Emerging Infectious Diseases

We report the transmission dynamics of SARS-CoV-2 across different settings from the initial COVID-19 cluster in Brunei, arisen from 19 attendees at the Malaysian Tablighi Jamaat gathering and resulted in 52 locally transmitted cases. Highest non-primary attack rates(ARs) were observed at a subsequent local religious gathering (14.8% [95%CI: 7.1,27.7]) and in the household (10.6% [95%CI: 7.3,15.1]. Household ARs of symptomatic cases were higher (14.4% [95%CI: 8.8,19.9]) than asymptomatic (4.4% [...

BackgroundThere are no data on SARS-CoV-2 seroprevalence in Africa though the COVID-19 epidemic curve and reported mortality differ from patterns seen elsewhere. We estimated the anti-SARS-CoV-2 antibody prevalence among blood donors in Kenya. MethodsWe measured anti-SARS-CoV-2 spike IgG prevalence by ELISA on residual blood donor samples obtained between April 30 and June 16, 2020. Assay sensitivity and specificity were 83% (95% CI 59-96%) and 99.0% (95% CI 98.1-99.5%), respectively. National ...

Reports have emerged documenting earlier SARS-CoV-2 cases than previously recognized. To investigate this possibility in the Bay Area, we retrospectively tested 1,700 samples from symptomatic individuals for the last 2 months of 2019. No SARS-CoV-2 positive pools were identified, consistent with limited transmission in this population at this time.

BackgroundThe absence of systematic surveillance for SARS-CoV-2 has curtailed accurate appraisal of transmission intensity. Our objective was to perform case detection of an entire rural community to quantify SARS-CoV-2 transmission using PCR and antibody testing. MethodsWe conducted a cross-sectional survey of the prevalence and cumulative incidence of SARSCoV-2 infection in the rural town of Bolinas, California (population 1,620), four weeks following shelter-in-place orders. Residents and co...

SARS-CoV-2 spread has proven to be especially difficult to mitigate in high risk settings, including nursing homes, cruises, prisons and various industrial settings. Among industrial settings, meat processing facilities in the United States have experienced particularly challenging outbreaks. We have sequenced SARS-CoV-2 whole viral genomes from individuals testing positive in an integrated regional healthcare system serving 21 counties in southwestern Wisconsin, northeastern Iowa and southeaste...

Using paired molecular and antibody testing for SARS-CoV-2 infection, we determined point prevalence and seroprevalence in a municipality in Louisiana, USA during the second phase of reopening. Infections were highly variable by race, work environment, and ZIP code. Census-weighted seroprevalence and point prevalence were 3.6% and 3.0%, respectively.

Using a novel recruitment method to reduce selection bias with paired molecular and antibody testing for SARS-CoV-2 infection, we determined point prevalence in a racially diverse municipality. Infections were highly variable by ZIP and differed by race. Overall census-weighted prevalence was 7.8% and the calculated infection fatality rate was 1.63%.

We conducted an extensive serological study to quantify population-level exposure and define correlates of immunity against SARS-CoV-2. We found that relative to mild COVID-19 cases, individuals with severe disease exhibited elevated authentic virus-neutralizing titers and antibody levels against nucleocapsid (N) and the receptor binding domain (RBD) and the S2 region of spike protein. Unlike disease severity, age and sex played lesser roles in serological responses. All cases, including asympto...

We quantitated anti-SARS/CoV-2 IgG and IgM by ELISA in self-collected blood samples (n=142) in arbitrarily-selected metro Atlanta residents, primarily acquaintances of the authors lab members from 4/17-4/27, 2020. Archived serum (n=34), serum from nucleic acid test (NAT)-positive subjects (n=4), and samples collected from NAT-positive community members (n=4) served to validate the assay. The range of anti-SARS/CoV-2 antibodies in archived and NAT-positive sera indicated need to compromise sensit...

Coxiella burnetii is a significant infectious pathogen that causes Q fever. Q fever is thought to be uncommon in the US and most human cases are believed to occur in agricultural livestock workers. However, the extent of community exposure to C. burnetii isnt known with certainty. Using nationally representative US National Health and Nutrition Examination Survey serologic, demographic and occupational history data, the magnitude of US adult general population exposure to C. burnetii excluding a...

The information on notifiable diseases in low- and middle-income countries is often incomplete, limiting our understanding of their epidemiology. Our study addresses this knowledge gap by analyzing microbiology laboratory and hospital admission data from 111 of 127 public referral hospitals in Thailand, excluding Bangkok, from January to December 2022. We evaluated factors associated with the incidence of notifiable bacterial diseases (NBDs) caused by 11 pathogens; including Brucella spp., Burkh...

We retrospectively identified eight episodes of Desulfovibrio bacteremia at a single tertiary-care hospital in Japan between 2020 and 2025. All patients were [≥]65 years of age, and most had comorbidities. The primary source of the infection was the abdomen. The isolates included two D. desulfuricans, D. fairfieldensis, D. falkowii, and D. legallii. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified only D. desulfuricans and D. fairfieldensis, whereas sequ...

BackgroundThe B.1.1.529 (Omicron BA.1) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global resurgence of coronavirus disease 2019 (Covid-19). The contribution of BA.1 infection to population immunity and its effect on subsequent resurgence of B.1.1.529 sub-lineages warrant investigation. MethodsWe conducted an epidemiologic survey to determine the sero-prevalence of SARS-CoV-2 IgG from March 1 to April 11, 2022, after the BA.1-dominant wave had subsided in Ga...

Powassan virus (POWV) is a tick-borne flavivirus that can cause lethal or debilitating neurological illness. It is canonically transmitted by Ixodes genus ticks but may interact with sympatric Dermacentor species. Here, we report the first detection of POWV lineage I from a pool of field-collected D. variabilis in New York state.

BackgroundIn low- and middle-income countries where SARS-CoV-2 testing is limited, seroprevalence studies can characterise the scale and determinants of the pandemic, as well as elucidate protection conferred by prior exposure. MethodsWe conducted repeated cross-sectional serosurveys (July 2020 - November 2021) using residual plasma from routine convenient blood samples from patients with non-COVID-19 conditions from Cape Town, South Africa. SARS-CoV-2 anti-nucleocapsid antibodies and linked cl...

Early data indicated that infection with Omicron BA.1 sub-lineage was associated with a lower risk of hospitalisation and severe illness, compared to Delta infection. Recently, the BA.2 sub-lineage has increased in many areas globally. We aimed to assess the severity of BA.2 infections compared to BA.1 in South Africa. We performed data linkages for (i) national COVID-19 case data, (ii) SARS-CoV-2 laboratory test data, and (iii) COVID-19 hospitalisations data, nationally. For cases identified us...

Highly pathogenic avian influenza (HPAI) H5N1 has caused the deaths of more than 100 million birds since 2021, and human cases since 1997 have been associated with significant morbidity and mortality. Given the recent detection of HPAI H5N1 in dairy cattle and H5N1 RNA detections in pasteurized retail milk in the United States, we established the Pan-Canadian Milk (PCM) Network. Through our network of collaborators from across Canada, retail milk is being procured longitudinally and sent to a ce...

Currently, a novel coronavirus 2019-nCoV causes an outbreak of viral pneumonia in Wuhan, China. Little is known about its epidemiological characteristics. Using the travel history and symptom onset of 88 confirmed cases that were detected outside Wuhan, we estimate the mean incubation period to be 6.4 (5.6 - 7.7, 95% CI) days, ranging from 2.1 to 11.1 days (2.5th to 97.5th percentile). These values help to inform case definitions for 2019-nCoV and appropriate durations for quarantine.

BackgroundWe characterized SARS-CoV-2 infections in a densely-populated, majority Latinx San Francisco community six-weeks into the citys shelter-in-place order. MethodsWe offered SARS-CoV-2 reverse transcription-PCR and antibody (Abbott ARCHITECT IgG) testing, regardless of symptoms, to all residents (>4 years) and workers in a San Francisco census tract (population: 5,174) at outdoor, community-mobilized events over four days. We estimated SARS-CoV-2 point prevalence (PCR-positive) and cumula...

Four confirmed mpox cases in South Ubangi province, Democratic Republic of the Congo, were linked to documented transboundary transmission from Central African Republic. Viral genome sequencing shows that the MPXV sequences belong to subclade Ia. This demonstrates the borderless nature of mpox and highlights the need for vigilant regional surveillance.