Last data update: Jun 24, 2024. (Total: 47078 publications since 2009)
Records 1-30 (of 38 Records) |
Query Trace: Blackstock A [original query] |
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The 2018-2019 FoodNet Population Survey: A tool to estimate risks and behaviors associated with enteric infections
Devine CJ , Molinari NA , Shah HJ , Blackstock AJ , Geissler A , Marder EP , Payne DC . Am J Epidemiol 2024 ![]() The FoodNet Population Survey is a periodic survey of randomly selected residents in 10 US sites on exposures and behaviors that may be associated with acute diarrheal infections and the health care sought for those infections. This survey is used to estimate the true disease burden of enteric illness in the United States and to estimate rates of exposure to potential sources of illness. Unlike previous FoodNet Population Surveys, this cycle used multiple sampling frames and administration modes, including cell phone and web-based questionnaires, that allowed for additional question topics and a larger sample size. It also oversampled children to increase representation of this population. Analytic modeling adjusted for mode effects when estimating the prevalence estimates of exposures and behaviors. This report describes the design, methodology, challenges, and descriptive results from the 2018-19 FoodNet Population Survey. |
Evaluation of SaTo pans as a new latrine technology in Kisumu County healthcare facilities, Kenya
Prentice-Mott G , Odhiambo A , Conners EE , Mwaki A , Blackstock AJ , Oremo J , Akelo O , Eleveld A , Quick R , Murphy J , Berendes DM . Trop Med Int Health 2023 28 (12) 881-889 OBJECTIVES: Innovations to improve public sanitation facilities, especially in healthcare facilities (HCFs) in low-income countries, are limited. SaTo pans represent novel, largely untested, modifications to reduce odour and flies and improve acceptability of HCF sanitation facilities. We conducted a pilot project to evaluate acceptability, cleanliness, flies and odour within latrines in 37 HCFs in Kisumu, Kenya, randomised into intervention (SaTo pan modifications) and control arms by sub-county and HCF level. METHODS: At baseline (pre-intervention) and endline (>3 months after completion of SaTo pan installations in latrines in intervention HCFs), we surveyed users, cleaners and in-charges, observed odour and cleanliness, and assessed flies using fly tape. Unadjusted difference-in-difference analysis compared changes from baseline to endline in patient-reported acceptability and observed latrine conditions between intervention and control HCFs. A secondary assessment compared patient-reported acceptability following use of SaTo pan versus non-SaTo pan latrines within intervention HCFs. RESULTS: Patient-reported acceptability of latrines was higher following the intervention (baseline: 87%, endline: 96%, p = 0.05). However, patient-reported acceptability was also high in the control arm (79%, 86%, p = 0.34), and the between-arm difference-in-difference was not significant. Enumerator-observed odour declined in intervention latrines (32%-14%) compared with controls (36%-51%, difference-in-difference ratio: 0.32, 95% confidence interval: 0.12-0.84), but changes in flies, puddling of urine and visible faeces did not differ between arms. In the secondary assessment, fewer intervention than control latrines had patient-reported flies (0% vs. 26%) and odour (18% vs. 50%), and reported satisfaction was greater. Most cleaners reported dropholes and floors were easier to clean in intervention versus controls; limited challenges with water for flushing were reported. CONCLUSIONS: Our results suggest SaTo pans may be acceptable by cleaners and users and reduce odour in HCF sanitation facilities, though challenges exist and further evaluation with larger sample sizes is needed. |
Observed face mask use outside retail chain stores during the COVID-19 pandemic in two cities in the state of Idaho, USA
Cahill ME , Lozoya SB , Griffin MA , Blackstock A , Stockdale K , Cowman S , Graff R , Spear C , Carter K . J Community Health 2023 During the COVID-19 pandemic, public health authorities have encouraged the use of face masks to minimize transmission within the community. To assess mask wear during a COVID-19 surge and guide public health response efforts, including public messaging on mask recommendations, we compared observed mask use in the largest city in each of Idaho's 2 most populous counties, both without a current mask mandate. We recorded mask usage by every third person exiting stores of 5 retail chains in Boise and Nampa during November 8-December 5, 2021. Observations were conducted during three time periods (morning, afternoon, and evening) on weekday and weekend days. A multivariable model with city, retail chain, and city-chain interaction was used to assess mask wear differences by city for each chain. Of 3021 observed persons, 22.0% wore masks. In Boise, 31.3% (430/1376) of observed persons wore masks; in Nampa, 14.3% (236/1645) wore masks. Among all persons wearing masks, > 94% wore masks correctly; cloth and surgical masks were most common. By retail chain, observed individuals at Boise locations were 2.3-5.7 times as likely to wear masks than persons at respective Nampa locations. This study provided a rapid, nonconfrontational assessment of public use of mitigation measures in 2 Idaho cities during a COVID-19 surge. |
Increasing incidence of invasive group A streptococcus disease, Idaho, USA, 2008-2019
Dunne EM , Hutton S , Peterson E , Blackstock AJ , Hahn CG , Turner K , Carter KK . Emerg Infect Dis 2022 28 (9) 1785-1795 We investigated invasive group A Streptococcus epidemiology in Idaho, USA, during 2008-2019 using surveillance data, medical record review, and emm (M protein gene) typing results. Incidence increased from 1.04 to 4.76 cases/100,000 persons during 2008-2019. emm 1, 12, 28, 11, and 4 were the most common types, and 2 outbreaks were identified. We examined changes in distribution of clinical syndrome, patient demographics, and risk factors by comparing 2008-2013 baseline with 2014-2019 data. Incidence was higher among all age groups during 2014-2019. Streptococcal toxic shock syndrome increased from 0% to 6.4% of cases (p = 0.02). We identified no differences in distribution of demographic or risk factors between periods. Results indicated that invasive group A Streptococcus is increasing among the general population of Idaho. Ongoing surveillance of state-level invasive group A Streptococcus cases could help identify outbreaks, track regional trends in incidence, and monitor circulating emm types. |
Multistate reptile- and amphibian-associated salmonellosis outbreaks in humans, United States, 20092018
Waltenburg MA , Perez A , Salah Z , Karp BE , Whichard J , Tolar B , Gollarza L , Koski L , Blackstock A , Basler C , Nichols M . Zoonoses Public Health 2022 69 (8) 925-937 Non-typhoidal Salmonella cause an estimated 1.4 million human illnesses, 26,000 hospitalizations and 400 deaths annually in the United States. Approximately 11% of these infections are attributed to animal contact. Reptiles and amphibians are known sources of salmonellosis; young children (aged <5 years) are disproportionately affected by reptile- and amphibian-associated salmonellosis (RAAS) outbreaks. We describe multistate RAAS outbreaks to characterize illnesses and inform prevention efforts. RAAS outbreaks were defined as ≥2 culture-confirmed human Salmonella infections with similar pulsed-field gel electrophoresis patterns and epidemiologic, laboratory or traceback evidence linking them to a common reptile/amphibian exposure. Data sources included the Animal Contact Outbreak Surveillance System; CDC Outbreak Response and Prevention Branch's outbreak management database; PulseNet, the national molecular subtyping network for foodborne disease surveillance in the United States; and the National Antimicrobial Resistance Monitoring System. Twenty-six RAAS outbreaks were reported during 2009–2018, resulting in 1465 illnesses and 306 hospitalizations. The outbreaks were associated with turtles (19), lizards (5), snakes (1) and frogs (1). Sixteen (61.5%) outbreaks were linked to small turtles (<4 inches), resulting in 914 illnesses. Forty-nine percent of outbreak-associated patients were aged <5 years. Of 362 patients/caregivers interviewed, 111 (30.7%) were aware that reptiles/amphibians can carry Salmonella. Among 267 patient isolates with antimicrobial susceptibility information, 20 (7.5%) were non-susceptible to ≥1 antibiotic used to treat human salmonellosis. RAAS outbreaks result in considerable morbidity, particularly among young children. Illnesses linked to small turtles are preventable through education, targeted outreach to caregivers and paediatricians, and when appropriate, enforcement. Historically, individual states and jurisdictions have enforced existing or promulgated new authorities to address outbreaks. Preventing future RAAS outbreaks requires addressing challenges related to the illegal sale/distribution of small turtles; and for legal reptile sales, providing information on RAAS risk to consumers at point of sale to support informed pet ownership decisions. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Zoonoses and Public Health published by Wiley-VCH GmbH. |
Pediatric medicaid visits for soil-transmitted helminth infections in the black belt region-Alabama, 2010-2018
Sanchez GV , Blackstock AJ , Davidson SL . Am J Trop Med Hyg 2022 106 (3) 867-869 Areas of rural Alabama may be at risk for re-emergence of soil-transmitted helminthiasis (STH) where environmental conditions are favorable for STH transmission, including in the agricultural Black Belt region. We describe pediatric Medicaid STH visits in Alabama and compare STH visit rates in Black Belt counties with those of non-Black Belt counties. Alabama Medicaid visit claims among children aged 0-18 years who received an STH diagnosis during January 2010-December 2018 were examined. STH-related pediatric visits were uncommon, but several counties with higher STH rates were identified. Visit rates did not differ meaningfully when comparing Black Belt with non-Black Belt region counties (rate ratio: 1.10; 95% CI: 0.73-1.64). Additional studies examining STH prevalence among children living in communities at risk for STH in Alabama can further clarify STH burden and identify communities experiencing environmental and sanitation conditions favorable to STH endemicity. |
Agritourism and Kidding Season: A Large Outbreak of Human Shiga Toxin-Producing Escherichia coli O157 (STEC O157) Infections Linked to a Goat Dairy Farm-Connecticut, 2016.
Nichols MC , Gacek P , Phan Q , Gambino-Shirley KJ , Gollarza LM , Schroeder MN , Mercante A , Mullins J , Blackstock A , Laughlin ME , Olson SM , Pizzo E , Nguyen TN , Mank L , Holmes-Talbot K , McNutt A , Noel D , Muyombwe A , Razeq JH , Lis MJ , Sherman B , Kasacek W , Whitlock L , Strockbine N , Martin H , Vidyaprakash E , McCormack P , Cartter M . Front Vet Sci 2021 8 744055 ![]() ![]() The objective of this study was to determine sources of Shiga toxin-producing Escherichia coli O157 (STEC O157) infection among visitors to Farm X and develop public health recommendations. A case-control study was conducted. Case-patients were defined as the first ill child (aged <18 years) in the household with laboratory-confirmed STEC O157, or physician-diagnosed hemolytic uremic syndrome with laboratory confirmation by serology, who visited Farm X in the 10 days prior to illness. Controls were selected from Farm X visitors aged <18 years, without symptoms during the same time period as case-patients. Environment and animal fecal samples collected from Farm X were cultured; isolates from Farm X were compared with patient isolates using whole genome sequencing (WGS). Case-patients were more likely than controls to have sat on hay bales at the doe barn (adjusted odds ratio: 4.55; 95% confidence interval: 1.41-16.13). No handwashing stations were available; limited hand sanitizer was provided. Overall, 37% (29 of 78) of animal and environmental samples collected were positive for STEC; of these, 62% (18 of 29) yielded STEC O157 highly related by WGS to patient isolates. STEC O157 environmental contamination and fecal shedding by goats at Farm X was extensive. Farms should provide handwashing stations with soap, running water, and disposable towels. Access to animal areas, including animal pens and enclosures, should be limited for young children who are at risk for severe outcomes from STEC O157 infection. National recommendations should be adopted to reduce disease transmission. |
An evaluation of water, sanitation, and hygiene status and household assets and their associations with soil-transmitted helminthiasis and reported diarrhea in Nueva Santa Rosa, Guatemala
Rao G , Blackstock AJ , Derado G , Cuéllar VM , Juliao P , Alvarez M , López B , Muñoz F , Thornton A , Patel JC , Lopez G , Rivera JG , Reyes L , Arvelo W , Lindblade KA , Roy SL . J Water Sanit Hyg Dev 2021 11 (3) 362-373 Soil-transmitted helminth (STH) infections and diarrheal illness affect billions of people yearly. We conducted a cross-sectional survey in Nueva Santa Rosa, Guatemala to identify factors associated with STH infections and diarrhea using univariable and multivariable logistic regression models. On multivariable analyses, we found associations between STH infections and two factors: school-aged children (odds ratio (OR) vs. adults: 2.35, 95% CI 1.10–4.99) and household drinking water supply classified as ‘other improved’ (OR vs. ‘improved’: 7.00, CI 1.22–40.14). Finished floors in the household vs. natural floors were highly protective (OR 0.16, CI 0.05–0.50) for STH infection. In crowded households (>2.5 people/bedroom), observing water present at handwashing stations was also protective (OR 0.32, CI 0.11–0.98). When adjusted for drying hands, diarrhea was associated with preschool-age children (OR vs. adults: 3.33, CI 1.83–6.04), spending >10 min per round trip collecting water (OR 1.90, CI 1.02–3.56), and having a handwashing station ≤10 m near a sanitation facility (OR 3.69, CI 1.33–10.21). Our study indicates that familiar WASH interventions, such as increasing drinking water quantity and water at handwashing stations in crowded homes, coupled with a hygiene intervention like finished flooring may hold promise for STH and diarrhea control programs. © 2021 The Authors. |
Trends in Racial and Ethnic Disparities in COVID-19 Hospitalizations, by Region - United States, March-December 2020.
Romano SD , Blackstock AJ , Taylor EV , El Burai Felix S , Adjei S , Singleton CM , Fuld J , Bruce BB , Boehmer TK . MMWR Morb Mortal Wkly Rep 2021 70 (15) 560-565 Persons from racial and ethnic minority groups are disproportionately affected by COVID-19, including experiencing increased risk for infection (1), hospitalization (2,3), and death (4,5). Using administrative discharge data, CDC assessed monthly trends in the proportion of hospitalized patients with COVID-19 among racial and ethnic groups in the United States during March-December 2020 by U.S. Census region. Cumulative and monthly age-adjusted COVID-19 proportionate hospitalization ratios (aPHRs) were calculated for racial and ethnic minority patients relative to non-Hispanic White patients. Within each of the four U.S. Census regions, the cumulative aPHR was highest for Hispanic or Latino patients (range = 2.7-3.9). Racial and ethnic disparities in COVID-19 hospitalization were largest during May-July 2020; the peak monthly aPHR among Hispanic or Latino patients was >9.0 in the West and Midwest, >6.0 in the South, and >3.0 in the Northeast. The aPHRs declined for most racial and ethnic groups during July-November 2020 but increased for some racial and ethnic groups in some regions during December. Disparities in COVID-19 hospitalization by race/ethnicity varied by region and became less pronounced over the course of the pandemic, as COVID-19 hospitalizations increased among non-Hispanic White persons. Identification of specific social determinants of health that contribute to geographic and temporal differences in racial and ethnic disparities at the local level can help guide tailored public health prevention strategies and equitable allocation of resources, including COVID-19 vaccination, to address COVID-19-related health disparities and can inform approaches to achieve greater health equity during future public health threats. |
Electronic dissemination of a web-based video promotes PrEP contemplation and conversation among US women engaged in care at Planned Parenthood
Calabrese SK , Lane SB , Caldwell A , Kaplan C , Dovidio JF , Galvao RW , Ogburn DF , Safon CB , Tekeste M , Taggart T , Modrakovic D , Wilbourn BC , Blackstock O , Kershaw TS . AIDS Behav 2021 25 (8) 2483-2500 We evaluated the acceptability and impact of a web-based PrEP educational video among women (n = 126) by comparing two Planned Parenthood centers: one assigned to a Web Video Condition and one to a Standard Condition. Most women reported the video helped them better understand what PrEP is (92%), how PrEP works (93%), and how to take PrEP (92%). One month post-intervention, more women in the Web Video Condition reported a high level of comfort discussing PrEP with a provider (82% vs. 48%) and commonly thinking about PrEP (36% vs. 4%). No women with linked medical records initiated PrEP during 1-year follow-up. |
Geographic range of recreational water-associated primary amebic meningoencephalitis, United States, 1978-2018
Gharpure R , Gleason M , Salah Z , Blackstock AJ , Hess-Homeier D , Yoder JS , Ali IKM , Collier SA , Cope JR . Emerg Infect Dis 2021 27 (1) 271-274 Naegleria fowleri is a free-living ameba that causes primary amebic meningoencephalitis (PAM), a rare but usually fatal disease. We analyzed trends in recreational water exposures associated with PAM cases reported during 1978-2018 in the United States. Although PAM incidence remained stable, the geographic range of exposure locations expanded northward. |
Estimate of burden and direct healthcare cost of infectious waterborne disease in the United States
Collier SA , Deng L , Adam EA , Benedict KM , Beshearse EM , Blackstock AJ , Bruce BB , Derado G , Edens C , Fullerton KE , Gargano JW , Geissler AL , Hall AJ , Havelaar AH , Hill VR , Hoekstra RM , Reddy SC , Scallan E , Stokes EK , Yoder JS , Beach MJ . Emerg Infect Dis 2021 27 (1) 140-149 Provision of safe drinking water in the United States is a great public health achievement. However, new waterborne disease challenges have emerged (e.g., aging infrastructure, chlorine-tolerant and biofilm-related pathogens, increased recreational water use). Comprehensive estimates of the health burden for all water exposure routes (ingestion, contact, inhalation) and sources (drinking, recreational, environmental) are needed. We estimated total illnesses, emergency department (ED) visits, hospitalizations, deaths, and direct healthcare costs for 17 waterborne infectious diseases. About 7.15 million waterborne illnesses occur annually (95% credible interval [CrI] 3.88 million-12.0 million), results in 601,000 ED visits (95% CrI 364,000-866,000), 118,000 hospitalizations (95% CrI 86,800-150,000), and 6,630 deaths (95% CrI 4,520-8,870) and incurring US $3.33 billion (95% CrI 1.37 billion-8.77 billion) in direct healthcare costs. Otitis externa and norovirus infection were the most common illnesses. Most hospitalizations and deaths were caused by biofilm-associated pathogens (nontuberculous mycobacteria, Pseudomonas, Legionella), costing US $2.39 billion annually. |
Estimating the incubation period of Salmonella urinary tract infections using foodborne outbreak data
Jacobs Slifka KM , Blackstock A , Nguyen V , Schwensohn C , Gieraltowski L , Mahon BE . Foodborne Pathog Dis 2020 17 (10) 628-630 Urinary tract infections (UTIs) are common and may occur in foodborne Salmonella outbreaks. Using data from PulseNet, the U.S. national molecular subtyping network for foodborne disease surveillance, we analyzed the 9781 Salmonella isolates associated with the 110 outbreaks from 2004 to 2013 that included at least one urine isolate. Within each outbreak, we calculated standardized isolation dates, using these dates in a linear mixed model to estimate the difference in incubation period for infections yielding stool versus urine isolates. We estimate that the incubation period for Salmonella UTIs is on average 10.6 (95% confidence interval 6.0-15.2) days longer than for gastrointestinal illness, suggesting that outbreak investigators should interview UTI patients about a longer time period before illness onset to identify sources of infection. |
Risk factors for epidemic cholera in Lusaka, Zambia-2017
Nanzaluka FH , Davis WW , Mutale L , Kapaya F , Sakubita P , Langa N , Gama A , N'Cho H S , Malambo W , Murphy J , Blackstock A , Mintz E , Riggs M , Mukonka V , Sinyange N , Yard E , Brunkard J . Am J Trop Med Hyg 2020 103 (2) 646-651 On October 6, 2017, the Zambia Ministry of Health declared a cholera outbreak in Lusaka. By December, 1,462 cases and 38 deaths had occurred (case fatality rate, 2.6%). We conducted a case-control study to identify risk factors and inform interventions. A case was any person with acute watery diarrhea (>/= 3 loose stools in 24 hours) admitted to a cholera treatment center in Lusaka from December 16 to 21, 2017. Controls were neighbors without diarrhea during the same time period. Up to two controls were matched to each case by age-group (1-4, 5-17, and >/= 18 years) and neighborhood. Surveyors interviewed cases and controls, tested free chlorine residual (FCR) in stored water, and observed the presence of soap in the home. Conditional logistic regression was used to generate matched odds ratios (mORs) based on subdistricts and age-groups with 95% CIs. We enrolled 82 cases and 132 controls. Stored water in 71% of case homes had an FCR > 0.2 mg/L. In multivariable analyses, those who drank borehole water (mOR = 2.4, CI: 1.1-5.6), had close contact with a cholera case (mOR = 6.2, CI: 2.5-15), and were male (mOR = 2.5, CI: 1.4-5.0) had higher odds of being a cholera case than their matched controls. The use of groundwater for drinking, contact with a cholera case, and male gender were associated with cholera. Based on these findings, we recommended health education about household water chlorination and hygiene in the home. Emergency responses included providing chlorinated water through emergency tanks and maintaining adequate FCR levels through close monitoring of water sources. |
Racial and ethnic differences in women's HIV risk and attitudes towards pre-exposure prophylaxis (PrEP) in the context of the substance use, violence, and depression syndemic
Willie TC , Kershaw TS , Blackstock O , Galvao RW , Safon CB , Tekeste M , Ogburn DF , Wilbourn B , Modrakovic D , Taggart T , Kaplan C , Caldwell A , Calabrese SK . AIDS Care 2020 33 (2) 1-10 Women with syndemic conditions, i.e., two or more co-occurring epidemics, are at elevated risk for HIV acquisition and are therefore prime candidates for pre-exposure prophylaxis (PrEP). However, PrEP uptake remains low among women, especially among Black and Hispanic women. This study examined associations of syndemic conditions with PrEP attitudes and HIV risk among women, and the moderating effect of race and ethnicity. In 2017, 271 non-Hispanic Black, non-Hispanic White, and Hispanic, PrEP-eligible women engaged in care at Planned Parenthood in the northeastern region of the U.S. completed an online survey. Participants reported syndemic conditions (i.e., intimate partner violence, depression, substance use), PrEP attitudes (e.g., PrEP interest), HIV sexual risk (e.g., multiple male sexual partners), and sociodemographics. Structural equation modeling was used to examine the effects of syndemic conditions on PrEP attitudes and HIV risk, and the moderating effect of race and ethnicity. Women with more syndemic conditions had a higher odds of reporting multiple male sexual partners. Syndemic conditions were positively associated with PrEP attitudes for Hispanic women than non-Hispanic Black and White women. Women with syndemic conditions, particularly Hispanic women, may be receptive to interventions promoting PrEP. |
Water, sanitation, and hygiene characteristics among HIV-positive households participating in the Global Enteric Multicenter Study in Rural Western Kenya, 2008-2012
Schilling KA , Awuor AO , Rajasingham A , Moke F , Omore R , Amollo M , Farag TH , Nasrin D , Nataro JP , Kotloff KL , Levine MM , Ayers T , Laserson K , Blackstock A , Rothenberg R , Stauber CE , Mintz ED , Breiman RF , O'Reilly CE . Am J Trop Med Hyg 2018 99 (4) 905-915 Diarrheal illness, a common occurrence among people living with human immunodeficiency virus (PLHIV), is largely preventable through access to safe drinking water quality, sanitation, and hygiene (WASH) facilities. We examined WASH characteristics among households with and without HIV-positive residents enrolled in the Global Enteric Multicenter Study (GEMS) in rural Western Kenya. Using univariable logistic regression, we examined differences between HIV-positive and HIV-negative households in regard to WASH practices. Among HIV-positive households, we explored the relationship between the length of time knowing their HIV status and GEMS enrollment. No statistically significant differences were apparent in the WASH characteristics among HIV-positive and HIV-negative households. However, we found differences in the WASH characteristics among HIV-positive households who were aware of their HIV status >/= 30 days before enrollment compared with HIV-positive households who found out their status < 30 days before enrollment or thereafter. Significantly more households aware of their HIV-positive status before enrollment reported treating their drinking water (odds ratio [OR] confidence interval [CI]: 2.34 [1.12, 4.86]) and using effective water treatment methods (OR [CI]: 9.6 [3.09, 29.86]), and had better drinking water storage practices. This suggests that within this region of Kenya, HIV programs are effective in promoting the importance of practicing positive WASH-related behaviors among PLHIV. |
Association of water quality with soil-transmitted helminthiasis and diarrhea in Nueva Santa Rosa, Guatemala, 2010
Matanock A , Lu X , Derado G , Cuellar VM , Juliao P , Alvarez M , Lopez B , Munoz F , Thornton A , Patel JC , Lopez G , Reyes L , Arvelo W , Blackstock AJ , Lindblade KA , Roy SL . J Water Health 2018 16 (5) 724-736 Improved water quality reduces diarrhea, but the impact of improved water quality on Ascaris and Trichuris, soil-transmitted helminths (STH) conveyed by the fecal-oral route, is less well described. To assess water quality associations with diarrhea and STH, we conducted a cross-sectional survey in households of south-eastern Guatemala. Diarrhea was self-reported in the past week and month. STH was diagnosed by stool testing using a fecal parasite concentrator method. We explored associations between Escherichia coli-positive source water (water quality) and disease outcomes using survey logistic regression models. Overall, 732 persons lived in 167 households where water was tested. Of these, 79.4% (581/732) had E. coli-positive water, 7.9% (58/732) had diarrhea within the week, 14.1% (103/732) had diarrhea within the month, and 6.6% (36/545) tested positive for Ascaris or Trichuris, including 1% (6/536) who also reported diarrhea. Univariable analysis found a statistically significant association between water quality and STH (odds ratio [OR] = 5.1, 95% confidence interval [CI] = 1.1-24.5) but no association between water quality and diarrhea. Waterborne transmission and effects of water treatment on STH prevalence should be investigated further. If a causal relationship is found, practices such as household water treatment including filtration might be useful adjuncts to sanitation, hygiene, and deworming in STH control programs. |
A tale of two healthcare-associated infections: Clostridium difficile coinfection among patients with Candidemia
Tsay S , Williams SR , Benedict K , Beldavs Z , Farley M , Harrison L , Schaffner W , Dumyati G , Blackstock A , Guh A , Vallabhaneni S . Clin Infect Dis 2018 68 (4) 676-679 Candidemia and Clostridium difficile infection (CDI) are important healthcare-associated infections that share certain risk factors. We sought to describe candidemia-CDI coinfection using population-based surveillance data. We found that nearly one in ten patients with candidemia had CDI coinfection. |
Clinical, environmental, and behavioral characteristics associated with Cryptosporidium infection among children with moderate-to-severe diarrhea in rural western Kenya, 2008-2012: The Global Enteric Multicenter Study (GEMS)
Delahoy MJ , Omore R , Ayers TL , Schilling KA , Blackstock AJ , Ochieng JB , Moke F , Jaron P , Awuor A , Okonji C , Juma J , Farag TH , Nasrin D , Panchalingam S , Nataro JP , Kotloff KL , Levine MM , Oundo J , Roellig DM , Xiao L , Parsons MB , Laserson K , Mintz ED , Breiman RF , O'Reilly CE . PLoS Negl Trop Dis 2018 12 (7) e0006640 BACKGROUND: Cryptosporidium is a leading cause of moderate-to-severe diarrhea (MSD) in young children in Africa. We examined factors associated with Cryptosporidium infection in MSD cases enrolled at the rural western Kenya Global Enteric Multicenter Study (GEMS) site from 2008-2012. METHODOLOGY/PRINCIPAL FINDINGS: At health facility enrollment, stool samples were tested for enteric pathogens and data on clinical, environmental, and behavioral characteristics collected. Each child's health status was recorded at 60-day follow-up. Data were analyzed using logistic regression. Of the 1,778 children with MSD enrolled as cases in the GEMS-Kenya case-control study, 11% had Cryptosporidium detected in stool by enzyme immunoassay; in a genotyped subset, 81% were C. hominis. Among MSD cases, being an infant, having mucus in stool, and having prolonged/persistent duration diarrhea were associated with being Cryptosporidium-positive. Both boiling drinking water and using rainwater as the main drinking water source were protective factors for being Cryptosporidium-positive. At follow-up, Cryptosporidium-positive cases had increased odds of being stunted (adjusted odds ratio [aOR] = 1.65, 95% CI: 1.06-2.57), underweight (aOR = 2.08, 95% CI: 1.34-3.22), or wasted (aOR = 2.04, 95% CI: 1.21-3.43), and had significantly larger negative changes in height- and weight-for-age z-scores from enrollment. CONCLUSIONS/SIGNIFICANCE: Cryptosporidium contributes significantly to diarrheal illness in young children in western Kenya. Advances in point of care detection, prevention/control approaches, effective water treatment technologies, and clinical management options for children with cryptosporidiosis are needed. |
Cholera epidemic - Lusaka, Zambia, October 2017-May 2018
Sinyange N , Brunkard JM , Kapata N , Mazaba ML , Musonda KG , Hamoonga R , Kapina M , Kapaya F , Mutale L , Kateule E , Nanzaluka F , Zulu J , Musyani CL , Winstead AV , Davis WW , N'Cho H S , Mulambya NL , Sakubita P , Chewe O , Nyimbili S , Onwuekwe EVC , Adrien N , Blackstock AJ , Brown TW , Derado G , Garrett N , Kim S , Hubbard S , Kahler AM , Malambo W , Mintz E , Murphy J , Narra R , Rao GG , Riggs MA , Weber N , Yard E , Zyambo KD , Bakyaita N , Monze N , Malama K , Mulwanda J , Mukonka VM . MMWR Morb Mortal Wkly Rep 2018 67 (19) 556-559 On October 6, 2017, an outbreak of cholera was declared in Zambia after laboratory confirmation of Vibrio cholerae O1, biotype El Tor, serotype Ogawa, from stool specimens from two patients with acute watery diarrhea. The two patients had gone to a clinic in Lusaka, the capital city, on October 4. Cholera cases increased rapidly, from several hundred cases in early December 2017 to approximately 2,000 by early January 2018 (Figure). In collaboration with partners, the Zambia Ministry of Health (MoH) launched a multifaceted public health response that included increased chlorination of the Lusaka municipal water supply, provision of emergency water supplies, water quality monitoring and testing, enhanced surveillance, epidemiologic investigations, a cholera vaccination campaign, aggressive case management and health care worker training, and laboratory testing of clinical samples. In late December 2017, a number of water-related preventive actions were initiated, including increasing chlorine levels throughout the city's water distribution system and placing emergency tanks of chlorinated water in the most affected neighborhoods; cholera cases declined sharply in January 2018. During January 10-February 14, 2018, approximately 2 million doses of oral cholera vaccine were administered to Lusaka residents aged >/=1 year. However, in mid-March, heavy flooding and widespread water shortages occurred, leading to a resurgence of cholera. As of May 12, 2018, the outbreak had affected seven of the 10 provinces in Zambia, with 5,905 suspected cases and a case fatality rate (CFR) of 1.9%. Among the suspected cases, 5,414 (91.7%), including 98 deaths (CFR = 1.8%), occurred in Lusaka residents. |
Association of maternal KIR gene content polymorphisms with reduction in perinatal transmission of HIV-1.
Omosun YO , Blackstock AJ , Williamson J , van Eijk AM , Ayisi J , Otieno J , Lal RB , Ter Kuile FO , Slutsker L , Shi YP . PLoS One 2018 13 (1) e0191733 ![]() ![]() The role of killer cell immunoglobulin-like receptors (KIRs) in the transmission of HIV-1 has not been extensively studied. Here, we investigated the association of KIR gene content polymorphisms with perinatal HIV-1 transmission. The KIR gene family comprising 16 genes was genotyped in 313 HIV-1 positive Kenyan mothers paired with their infants. Gene content polymorphisms were presented as presence of individual KIR genes, haplotypes, genotypes and KIR gene concordance. The genetic data were analyzed for associations with perinatal transmission of HIV. There was no association of infant KIR genes with perinatal HIV-1 transmission. After adjustment for gravidity, viral load, and CD4 cell count, there was evidence of an association between reduction in perinatal HIV-1 transmission and the maternal individual KIR genes KIR2DL2 (adjusted OR = 0.50; 95% CI: 0.24-1.02, P = 0.06), KIR2DL5 (adjusted OR = 0.47; 95% CI: 0.23-0.95, P = 0.04) and KIR2DS5 (adjusted OR = 0.39; 95% CI: 0.18-0.80, P = 0.01). Furthermore, these maternal KIR genes were only significantly associated with reduction in perinatal HIV transmission in women with CD4 cell count >/= 350 cells/ mul and viral load <10000 copies/ml. Concordance analysis showed that when both mother and child had KIR2DS2, there was less likelihood of perinatal HIV-1 transmission (adjusted OR = 0.44; 95% CI: 0.20-0.96, P = 0.039). In conclusion, the maternal KIR genes KIR2DL2, KIR2DL5, KIR2DS5, and KIR2DS2 were associated with reduction of HIV-1 transmission from mother to child. Furthermore, maternal immune status is an important factor in the association of KIR with perinatal HIV transmission. |
Shiga Toxin-Producing E. coli Infections Associated with Flour.
Crowe SJ , Bottichio L , Shade LN , Whitney BM , Corral N , Melius B , Arends KD , Donovan D , Stone J , Allen K , Rosner J , Beal J , Whitlock L , Blackstock A , Wetherington J , Newberry LA , Schroeder MN , Wagner D , Trees E , Viazis S , Wise ME , Neil KP . N Engl J Med 2017 377 (21) 2036-2043 ![]() ![]() Background In 2016, a multijurisdictional team investigated an outbreak of Shiga toxin-producing Escherichia coli (STEC) serogroup O121 and O26 infections linked to contaminated flour from a large domestic producer. Methods A case was defined as infection with an outbreak strain in which illness onset was between December 21, 2015, and September 5, 2016. To identify exposures associated with the outbreak, outbreak cases were compared with non-STEC enteric illness cases, matched according to age group, sex, and state of residence. Products suspected to be related to the outbreak were collected for STEC testing, and a common point of contamination was sought. Whole-genome sequencing was performed on isolates from clinical and food samples. Results A total of 56 cases were identified in 24 states. Univariable exact conditional logistic-regression models of 22 matched sets showed that infection was significantly associated with the use of one brand of flour (odds ratio, 21.04; 95% confidence interval [CI], 4.69 to 94.37) and with tasting unbaked homemade dough or batter (odds ratio, 36.02; 95% CI, 4.63 to 280.17). Laboratory testing isolated the outbreak strains from flour samples, and whole-genome sequencing revealed that the isolates from clinical and food samples were closely related to one another genetically. Trace-back investigation identified a common flour-production facility. Conclusions This investigation implicated raw flour as the source of an outbreak of STEC infections. Although it is a low-moisture food, raw flour can be a vehicle for foodborne pathogens. |
Animal-related factors associated with moderate-to-severe diarrhea in children younger than five years in western Kenya: A matched case-control study
Conan A , O'Reilly CE , Ogola E , Ochieng JB , Blackstock AJ , Omore R , Ochieng L , Moke F , Parsons MB , Xiao L , Roellig D , Farag TH , Nataro JP , Kotloff KL , Levine MM , Mintz ED , Breiman RF , Cleaveland S , Knobel DL . PLoS Negl Trop Dis 2017 11 (8) e0005795 BACKGROUND: Diarrheal disease remains among the leading causes of global mortality in children younger than 5 years. Exposure to domestic animals may be a risk factor for diarrheal disease. The objectives of this study were to identify animal-related exposures associated with cases of moderate-to-severe diarrhea (MSD) in children in rural western Kenya, and to identify the major zoonotic enteric pathogens present in domestic animals residing in the homesteads of case and control children. METHODOLOGY/PRINCIPAL FINDINGS: We characterized animal-related exposures in a subset of case and control children (n = 73 pairs matched on age, sex and location) with reported animal presence at home enrolled in the Global Enteric Multicenter Study in western Kenya, and analysed these for an association with MSD. We identified potentially zoonotic enteric pathogens in pooled fecal specimens collected from domestic animals resident at children's homesteads. Variables that were associated with decreased risk of MSD were washing hands after animal contact (matched odds ratio [MOR] = 0.2; 95% CI 0.08-0.7), and presence of adult sheep that were not confined in a pen overnight (MOR = 0.1; 0.02-0.5). Variables that were associated with increased risk of MSD were increasing number of sheep owned (MOR = 1.2; 1.0-1.5), frequent observation of fresh rodent excreta (feces/urine) outside the house (MOR = 7.5; 1.5-37.2), and participation of the child in providing water to chickens (MOR = 3.8; 1.2-12.2). Of 691 pooled specimens collected from 2,174 domestic animals, 159 pools (23%) tested positive for one or more potentially zoonotic enteric pathogens (Campylobacter jejuni, C. coli, non-typhoidal Salmonella, diarrheagenic E. coli, Giardia, Cryptosporidium, or rotavirus). We did not find any association between the presence of particular pathogens in household animals, and MSD in children. CONCLUSIONS AND SIGNIFICANCE: Public health agencies should continue to promote frequent hand washing, including after animal contact, to reduce the risk of MSD. Future studies should address specific causal relations of MSD with sheep and chicken husbandry practices, and with the presence of rodents. |
Community laboratory testing for cryptosporidium: Multicenter study retesting public health surveillance stool samples positive for cryptosporidium by rapid cartridge assay with direct fluorescent antibody testing
Roellig DM , Yoder JS , Madison-Antenucci S , Robinson TJ , Van TT , Collier SA , Boxrud D , Monson T , Bates LA , Blackstock AJ , Shea S , Larson K , Xiao L , Beach M . PLoS One 2017 12 (1) e0169915 Cryptosporidium is a common cause of sporadic diarrheal disease and outbreaks in the United States. Increasingly, immunochromatography-based rapid cartridge assays (RCAs) are providing community laboratories with a quick cryptosporidiosis diagnostic method. In the current study, the Centers for Disease Control and Prevention (CDC), the Association of Public Health Laboratories (APHL), and four state health departments evaluated RCA-positive samples obtained during routine Cryptosporidium testing. All samples underwent "head to head" re-testing using both RCA and direct fluorescence assay (DFA). Community level results from three sites indicated that 54.4% (166/305) of Meridian ImmunoCard STAT! positives and 87.0% (67/77) of Remel Xpect positives were confirmed by DFA. When samples were retested by RCA at state laboratories and compared with DFA, 83.3% (155/186) of Meridian ImmunoCard STAT! positives and 95.2% (60/63) of Remel Xpect positives were confirmed. The percentage of confirmed community results varied by site: Minnesota, 39.0%; New York, 63.9%; and Wisconsin, 72.1%. The percentage of confirmed community results decreased with patient age; 12.5% of community positive tests could be confirmed by DFA for patients 60 years of age or older. The percentage of confirmed results did not differ significantly by sex, storage temperature, time between sample collection and testing, or season. Findings from this study demonstrate a lower confirmation rate of community RCA positives when compared to RCA positives identified at state laboratories. Elucidating the causes of decreased test performance in order to improve overall community laboratory performance of these tests is critical for understanding the epidemiology of cryptosporidiosis in the United States (US). |
Notes from the field: Outbreak of Escherichia coli O157 infections associated with goat dairy farm visits - Connecticut, 2016
Laughlin M , Gambino-Shirley K , Gacek P , Phan Q , Stevenson L , Mercante A , Mullins J , Burnworth L , Blackstock A , Razeq JH , Cartter M , Nichols M . MMWR Morb Mortal Wkly Rep 2016 65 (5051) 1453-1454 On March 24, 2016, the Connecticut Department of Public Health (DPH) identified a cluster of seven culture-confirmed Shiga toxin–producing Escherichia coli (STEC) infections in patients ranging in age from 2 to 25 years. All seven patients reported bloody diarrhea; four were evaluated in an emergency department, three were hospitalized, and two developed hemolytic uremic syndrome (HUS). Six of the seven patients reported visiting the same goat dairy farm in southeastern Connecticut during the week preceding illness onset. An investigation was initiated by DPH, the Connecticut Department of Agriculture, CDC, and the local health district to determine the magnitude of the outbreak, identify risk factors and potential sources of infection, and develop recommendations to prevent further illnesses. A total of 50 confirmed cases of E. coli infection were associated with the outbreak, including 47 with an epidemiologic link to the goat farm. | PulseNet, the national molecular subtyping laboratory network for foodborne disease surveillance, and pulsed-field gel electrophoresis (PFGE) were used to identify the outbreak strains as STEC O157. A confirmed case was defined as 1) laboratory-confirmed E. coli O157 infection with the PFGE-identified outbreak strain or 2) physician-diagnosed HUS during March–April 2016 in a person with an epidemiologic link to the goat farm. Ill farm visitors were encouraged to contact DPH through a public statement released on March 28, 2016, and were interviewed about their visit. Environmental samples were collected at the farm and cultured, and the resulting bacterial isolates were compared with patient isolates using PFGE and whole genome sequencing. Genetic relatedness of isolates was determined by high-quality single nucleotide polymorphism analysis. The 2013 Compendium of Measures to Prevent Disease Associated with Animals in Public Settings was used to evaluate practices at the farm (1). |
Changing patterns in enteric fever incidence and increasing antibiotic resistance of enteric fever isolates in the United States, 2008-2012
Date KA , Newton AE , Medalla F , Blackstock A , Richardson L , McCullough A , Mintz ED , Mahon BE . Clin Infect Dis 2016 63 (3) 322-9 BACKGROUND: Enteric fever in the United States has been primarily associated with travel and with worrisome changes in global patterns of antimicrobial resistance. We present the first comprehensive report of National Typhoid and Paratyphoid Fever Surveillance System (NTPFS) data for a 5-year period (2008-2012). METHODS: We reviewed data on laboratory-confirmed cases reported to NTPFS, and related antimicrobial susceptibility results of SalmonellaTyphi and Paratyphi A isolates sent for testing by participating public health laboratories to CDC's National Antimicrobial Resistance Monitoring System laboratory. RESULTS: During 2008-2012, 2341 enteric fever cases were reported, 80% typhoid and 20% paratyphoid A. The proportion caused by paratyphoid A increased from 16% (2008) to 22% (2012). Foreign travel within 30 days preceding illness onset was reported by 1961 (86%) patients (86% typhoid and 92% paratyphoid A). Travel to southern Asia was common (82% for typhoid, 97% for paratyphoid A). Among 1091 (58%) typhoid and 262 (56%) paratyphoid A isolates tested for antimicrobial susceptibility, the proportion resistant to nalidixic acid (NAL-R) increased from 2008 to 2012 (Typhi 60% to 68%; Paratyphi-A 91% to 94%). Almost all NAL-R isolates were resistant or showed decreased susceptibility to ciprofloxacin. Resistance to at least ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole (multidrug resistant [MDR]) was limited to Typhi isolates, primarily acquired in southern Asia (13%). Most MDR isolates were also NAL-R. CONCLUSIONS: Enteric fever in the US is primarily associated with travel to southern Asia and increasing resistance is adding to treatment challenges. A bivalent typhoid and paratyphoid vaccine is needed. |
A cross-sectional study of water, sanitation, and hygiene-related risk factors for soil-transmitted helminth infection in urban school- and preschool-aged children in Kibera, Nairobi
Worrell CM , Wiegand RE , Davis SM , Odero KO , Blackstock A , Cuellar VM , Njenga SM , Montgomery JM , Roy SL , Fox LM . PLoS One 2016 11 (3) e0150744 Soil-transmitted helminth (STH) infections affect persons living in areas with poor water, sanitation, and hygiene (WASH). Preschool-aged children (PSAC) and school-aged children (SAC) are disproportionately affected by STH infections. We aimed to identify WASH factors associated with STH infection among PSAC and SAC in Kibera, Kenya. In 2012, households containing a PSAC or SAC were randomly selected from those enrolled in the International Emerging Infections Program, a population-based surveillance system. We administered a household questionnaire, conducted environmental assessments for WASH, and tested three stools from each child for STH eggs using the Kato-Katz method. WASH factors were evaluated for associations with STH infection using univariable and multivariable Poisson regression. Any-STH prevalence was 40.8% among 201 PSAC and 40.0% among 475 SAC enrolled. Using the Joint Monitoring Programme water and sanitation classifications, 1.5% of households reported piped water on premises versus 98.5% another improved water source; 1.3% reported improved sanitation facilities, while 81.7% used shared sanitation facilities, 13.9% had unimproved facilities, and 3.1% reported no facilities (open defecation). On univariable analysis, STH infection was significantly associated with a household toilet located off-premises (prevalence ratio (PR) = 1.33; p = 0.047), while always treating water (PR = 0.81; p = 0.04), covering drinking water containers (PR = 0.75; p = 0.02), using clean towels during hand drying (PR = 0.58; p<0.01), having finished household floor material (PR = 0.76; p<0.01), having electricity (PR = 0.70; p<0.01), and increasing household elevation in 10-meter increments (PR = 0.89; p<0.01) were protective against STH infection. On multivariable analysis, usually versus always treating water was associated with increased STH prevalence (adjusted prevalence ratio (aPR) = 1.52; p<0.01), while having finished household floor material (aPR = 0.76; p = 0.03), reported child deworming in the last year (aPR = 0.76; p<0.01), and 10-meter household elevation increases (aPR = 0.89; p<0.01) were protective against infection. The intersection between WASH and STH infection is complex; site-specific WASH interventions should be considered to sustain the gains made by deworming activities. |
Evaluation of point-of-contact circulating cathodic antigen assays for the detection of Schistosoma mansoni infection in low-, moderate-, and high-prevalence schools in Western Kenya
Foo KT , Blackstock AJ , Ochola EA , Matete DO , Mwinzi PN , Montgomery SP , Karanja DM , Secor WE . Am J Trop Med Hyg 2015 92 (6) 1227-32 We evaluated the performance of a point-of-contact circulating cathodic antigen assay (POC-CCA) to detect schistosome infections in primary school children (N = 1,801) living in areas with low, moderate, and high Schistosoma mansoni prevalence in western Kenya. The commercially available assay (CCA-1) and a second, experimental formulation (CCA-2) were compared against Kato-Katz stool examinations and an anti-schistosome enzyme-linked immunosorbent assay (ELISA). A latent class model based on the four tests was used to establish "true infection status" in three different zones based on their distance from Lake Victoria. As a screening tool for community treatment according to World Health Organization (WHO) guidelines, the Kato-Katz examination was in closest agreement with the latent class model, followed by the experimental CCA-2, soluble adult worm antigen preparation (SWAP) ELISA, and CCA-1, which had high sensitivity compared with the other tests but was consistently the least specific. Our experience suggests that POC-CCA tests offer a field-friendly alternative to Kato-Katz, but need further interpretation for appropriate field use. |
Cholera at the crossroads: the association between endemic cholera and national access to improved water sources and sanitation
Nygren BL , Blackstock AJ , Mintz ED . Am J Trop Med Hyg 2014 91 (5) 1023-8 We evaluated World Health Organization (WHO) national water and sanitation coverage levels and the infant mortality rate as predictors of endemic cholera in the 5-year period following water and sanitation coverage estimates using logistic regression, receiver operator characteristic curves, and different definitions of endemicity. Each was a significant predictors of endemic cholera at P < 0.001. Using a value of 250 for annual cases reported in 3 of 5 years, a national water access level of 71% has 65% sensitivity and 65% specificity in predicting endemic cholera, a sanitation access level of 39% has 63% sensitivity and 62% specificity, and an infant mortality rate of 65/1,000 has 67% sensitivity and 69% specificity. Our findings reveal the tradeoff between sensitivity and specificity for these predictors of endemic cholera and highlight the substantial uncertainty in the data. More accurate global surveillance data will enable more precise characterization of the benefits of improved water and sanitation. |
A longitudinal analysis of the effect of mass drug administration on acute inflammatory episodes and disease progression in lymphedema patients in Leogane, Haiti
Eddy BA , Blackstock AJ , Williamson JM , Addiss DG , Streit TG , Beau de Rochars VM , Fox LM . Am J Trop Med Hyg 2014 90 (1) 80-8 We conducted a longitudinal analysis of 117 lymphedema patients in a filariasis-endemic area of Haiti during 1995-2008. No difference in lymphedema progression between those who received or did not receive mass drug administration (MDA) was found on measures of foot (P = 0.24), ankle (P = 0.87), or leg (P = 0.46) circumference; leg volume displacement (P = 0.09), lymphedema stage (P = 0.93), or frequency of adenolymphangitis (ADL) episodes (P = 0.57). Rates of ADL per year were greater after initiation of MDA among both groups (P < 0.01). Nevertheless, patients who received MDA reported improvement in four areas of lymphedema-related quality of life (P ≤ 0.01). Decreases in foot and ankle circumference and ADL episodes were observed during the 1995-1998 lymphedema management study (P ≤ 0.01). This study represents the first longitudinal, quantitative, leg-specific analysis examining the clinical effect of diethylcarbamazine on lymphedema progression and ADL episodes. |
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