Prevalence of Latent Tuberculosis Infection Among Non-US-Born Persons by Country of Birth-United States, 2012-2017.

BACKGROUND: Most tuberculosis (TB) disease in the United States (US) is attributed to reactivation of remotely acquired latent TB infection (LTBI) in non-US-born persons who were likely infected with Mycobacterium tuberculosis in their countries of birth. Information on LTBI prevalence by country of birth could help guide local providers and health departments to scale up the LTBI screening and preventive treatment needed to advance progress toward TB elimination. METHODS: A total of 13 805 non-US-born persons at high risk of TB infection or progression to TB disease were screened for LTBI at 16 clinical sites located across the United States with a tuberculin skin test, QuantiFERON Gold In-Tube test, and T-SPOT.TB test. Bayesian latent class analysis was applied to test results to estimate LTBI prevalence and associated credible intervals (CrIs) for each country or world region of birth. RESULTS: Among the study population, the estimated LTBI prevalence was 31% (95% CrI, 26%-35%). Country-of-birth-level LTBI prevalence estimates were highest for persons born in Haiti, Peru, Somalia, Ethiopia, Vietnam, and Bhutan, ranging from 42% to 55%. LTBI prevalence estimates were lowest for persons born in Colombia, Malaysia, and Thailand, ranging from 8% to 13%. CONCLUSIONS: LTBI prevalence in persons born outside the US varies widely by country. These estimates can help target community outreach efforts to the highest-risk groups.

Water treatment and handwashing practices in rural Kenyan health care facilities and households six years after the installation of portable water stations and hygiene training.

Many health care facilities (HCFs) and households in low-and-middle-income countries have inadequate access to water for hygiene and consumption. To address these problems, handwashing and drinking water stations were installed in 53 HCFs with prevention-of-mother-to-child-transmission of HIV programs in Kenya in 2005, and hygiene education was provided to health workers and clinic clients. To assess this program, we selected a random sample of 30 HCFs, observed the percentage of handwashing and drinking water stations that were functional and in use, and after that interviewed health providers and clients about hygiene and water treatment. Results indicated that, six years after implementation, 80.0% of HCFs had at least one functional handwashing station and 83.3% had at least one functional drinking water station. In addition, 60% of HCFs had soap at ≥ one handwashing stations, and 23.3% had ≥ one container with detectable free chlorine. Of 299 clients (mothers with ≥ one child under five), 57.2% demonstrated proper water treatment knowledge, 93.3% reported ever using water treatment products, 16.4% had detectable chlorine residual in stored water, and 89.0% demonstrated proper handwashing technique. Six years after program implementation, although most HCFs had water stations and most clients could demonstrate proper handwashing technique, water stored in most clinics and homes was not treated.

Risk Factors for Acanthamoeba Keratitis-A Multistate Case-Control Study, 2008-2011.

OBJECTIVE: To identify modifiable risk factors contributing to Acanthamoeba keratitis (AK) infection. METHODS: A case-control investigation was conducted. Case patients were soft contact lens wearers with laboratory-confirmed AK. Control were soft contact lens wearers ≥12 years of age, with no history of AK. Case patients were recruited from 14 ophthalmology referral centers and a clinical laboratory. Control were matched on state of residence and type of primary eye care provider (ophthalmologist or optometrist). Participants were interviewed using a standardized questionnaire. Univariable and multivariable conditional logistic regression analyses were conducted. Matched odds ratios (mORs) were calculated. RESULTS: Participants included 88 case patients and 151 matched control. Case patients were more likely to be aged <25 years (unadjusted mOR 2.7, 95% confidence interval 1.3-5.5) or aged >53 years (mOR 2.5, 1.1-5.7), and more likely to be men (mOR 2.6, 1.4-4.8). Unadjusted analyses identified multiple risk factors: rinsing (mOR 6.3, 1.3-29.9) and storing lenses in tap water (mOR 3.9, 1.2-12.3), topping off solution in the lens case (mOR 4.0, 2.0-8.0), having worn lenses ≤5 years (mOR 2.4, 1.3-4.4), rinsing the case with tap water before storing lenses (mOR 2.1, 1.1-4.1), and using hydrogen peroxide (mOR 3.6, 1.1-11.7) versus multipurpose solution. Significant risk factors in multivariable modeling included age >53 years, male sex, topping off, and using saline solution. CONCLUSIONS: Numerous modifiable risk factors for AK were identified, mostly involving hygiene practices. To reduce the risk of AK, lens wearers should observe recommended lens care practices.

Diffusion of Handwashing Knowledge and Water Treatment Practices From Mothers in an Antenatal Hygiene Promotion Program to Nonpregnant Friends and Relatives, Machinga District, Malawi.

Access to safe drinking water and improved hygiene are essential for preventing diarrheal diseases in low- and middle-income countries. Integrating water treatment and hygiene products into antenatal clinic care can motivate water treatment and handwashing among pregnant women. Free water hygiene kits (water storage containers, sodium hypochlorite water treatment solution, and soap) and refills of water treatment solution and soap were integrated into antenatal care and delivery services in Machinga District, Malawi, resulting in improved water treatment and hygiene practices in the home and increased maternal health service use. To determine whether water treatment and hygiene practices diffused from maternal health program participants to friends and relatives households in the same communities, we assessed the practices of 106 nonpregnant friends and relatives of these new mothers at baseline and 1-year follow-up. At follow-up, friends and relatives were more likely than at baseline to have water treatment products observable in the home (33.3% vs. 1.2%, p < 0.00001) and detectable free chlorine residual in their water, confirming water treatment (35.7% vs. 1.4%; p < 0.00001). Qualitative data from in-depth interviews also suggested that program participants helped motivate adoption of water treatment and hygiene behaviors among their friends and relatives.

Sanitation and Hygiene-Specific Risk Factors for Moderate-to-Severe Diarrhea in Young Children in the Global Enteric Multicenter Study, 2007-2011: Case-Control Study.

BACKGROUND: Diarrheal disease is the second leading cause of disease in children less than 5 y of age. Poor water, sanitation, and hygiene conditions are the primary routes of exposure and infection. Sanitation and hygiene interventions are estimated to generate a 36% and 48% reduction in diarrheal risk in young children, respectively. Little is known about whether the number of households sharing a sanitation facility affects a child's risk of diarrhea. The objective of this study was to describe sanitation and hygiene access across the Global Enteric Multicenter Study (GEMS) sites in Africa and South Asia and to assess sanitation and hygiene exposures, including shared sanitation access, as risk factors for moderate-to-severe diarrhea (MSD) in children less than 5 y of age. METHODS/FINDINGS: The GEMS matched case-control study was conducted between December 1, 2007, and March 3, 2011, at seven sites in Basse, The Gambia; Nyanza Province, Kenya; Bamako, Mali; Manhiça, Mozambique; Mirzapur, Bangladesh; Kolkata, India; and Karachi, Pakistan. Data was collected for 8,592 case children aged <5 y old experiencing MSD and for 12,390 asymptomatic age, gender, and neighborhood-matched controls. An MSD case was defined as a child with a diarrheal illness <7 d duration comprising ≥3 loose stools in 24 h and ≥1 of the following: sunken eyes, skin tenting, dysentery, intravenous (IV) rehydration, or hospitalization. Site-specific conditional logistic regression models were used to explore the association between sanitation and hygiene exposures and MSD. Most households at six sites (>93%) had access to a sanitation facility, while 70% of households in rural Kenya had access to a facility. Practicing open defecation was a risk factor for MSD in children <5 y old in Kenya. Sharing sanitation facilities with 1-2 or ≥3 other households was a statistically significant risk factor for MSD in Kenya, Mali, Mozambique, and Pakistan. Among those with a designated handwashing area near the home, soap or ash were more frequently observed at control households and were significantly protective against MSD in Mozambique and India. CONCLUSIONS: This study suggests that sharing a sanitation facility with just one to two other households can increase the risk of MSD in young children, compared to using a private facility. Interventions aimed at increasing access to private household sanitation facilities may reduce the burden of MSD in children. These findings support the current World Health Organization/ United Nations Children's Emergency Fund (UNICEF) system that categorizes shared sanitation as unimproved.

A rapid assessment of drinking water quality in informal settlements after a cholera outbreak in Nairobi, Kenya.

Populations living in informal settlements with inadequate water and sanitation infrastructure are at risk of epidemic disease. In 2010, we conducted 398 household surveys in two informal settlements in Nairobi, Kenya with isolated cholera cases. We tested source and household water for free chlorine residual (FCR) and Escherichia coli in approximately 200 households. International guidelines are ≥0.5 mg/L FCR at source, ≥0.2 mg/L at household, and <1 E. coli/100 mL. In these two settlements, 82% and 38% of water sources met FCR guidelines; and 7% and 8% were contaminated with E. coli, respectively. In household stored water, 82% and 35% met FCR guidelines and 11% and 32% were contaminated with E. coli, respectively. Source water FCR≥0.5 mg/L (p=0.003) and reported purchase of a household water treatment product (p=0.002) were associated with increases in likelihood that household stored water had ≥0.2 mg/L FCR, which was associated with a lower likelihood of E. coli contamination (p<0.001). These results challenge the assumption that water quality in informal settlements is universally poor and the route of disease transmission, and highlight that providing centralized water with ≥0.5 mg/L FCR or (if not feasible) household water treatment technologies reduces the risk of waterborne cholera transmission in informal settlements.

Recurrence of Helicobacter pylori infection in Bolivian children and adults after a population-based "screen and treat" strategy.

BACKGROUND: Strategies to prevent gastric cancer by decreasing Helicobacter pylori infections in high-prevalence, low-income countries could include a population-based "screen and treat" eradication program. METHODS: We tested residents of two rural villages for H. pylori infection using urea breath test (UBT), treated infected persons using directly observed therapy (DOT), retested for cure, and retested after 1 year later for H. pylori infection. FINDINGS: We tested 1,065 (92%) of 1153 residents from two villages in rural Bolivia. Baseline H. pylori prevalence was 80% (95% confidence interval [CI]: 78-84). Age-specific cure rates were similar (≥92%) after DOT. Among those cured, 12% (95% CI: 8-15) had recurrent infection. Age-specific annual H. pylori recurrence rates for combined villages were 20% (95% CI: 10-29) in persons <5 years, 20% (95% CI: 10-29) in 5-9 years, 8% (95% CI: 1-15) in 10-14 years, and 8% (95% CI: 4-12) in persons ≥15 years. Compared with the referent population, those ≥15 years, recurrent infections were significantly more likely in children <5 years (odds ratios [OR] 2.7, 95% CI: 1.2-5.8) and 5-9 years (OR 2.7, 95% CI: 1.4-5.1). INTERPRETATION: Children <10 years had high H. pylori recurrence rates following a population-based screen and treat program; this H. pylori eradication strategy may not be feasible in high-prevalence, low-income settings.

Evaluation of a rapid cholera response activity--Nyanza Province, Kenya, 2008.

BACKGROUND: In response to recurrent cholera outbreaks in Nyanza Province, Kenya, a local nongovernmental organization assisted the Ministry of Health by providing cholera education activities to some cholera-affected communities. We evaluated the impact on cholera prevention knowledge and practices. METHODS: In November-December 2008, we conducted a cross-sectional household survey and tested stored water for chlorine in 6 cholera-affected enumeration areas (intervention-EAs) where response activities had occurred between March-September 2008, and 6 comparison-EAs with no known reports of cholera outbreaks or response activities. RESULTS: We enrolled 358 individuals from intervention-EAs and 365 from comparison-EAs. Overall, >80% knew cholera symptoms and over 60% knew that water treatment prevented diarrhea; <20% had chlorine residual in stored water. More intervention-EA respondents than comparison-EA respondents recalled a cholera outbreak in their community (52% vs 19%, P < .0001), and of those, 51% versus 39%, respectively, had attended a cholera response event. Detectable chlorine residuals in stored water were found in a higher percentage of intervention-EA and comparison-EA event attendees (21% and 25%, respectively) than nonattendees (17% and 8%, respectively). CONCLUSIONS: There was a gap between knowledge and practice of water treatment as a cholera preventive measure. Cholera event attendance may have modestly motivated increased household water treatment.

A national cholera epidemic with high case fatality rates--Kenya 2009.

BACKGROUND: Cholera remains endemic in sub-Saharan Africa. We characterized the 2009 cholera outbreaks in Kenya and evaluated the response. METHODS: We analyzed surveillance data and estimated case fatality rates (CFRs). Households in 2 districts, East Pokot (224 cases; CFR = 11.7%) and Turkana South (1493 cases; CFR = 1.0%), were surveyed. We randomly selected 15 villages and 8 households per village in each district. Healthcare workers at 27 health facilities (HFs) were surveyed in both districts. RESULTS: In 2009, cholera outbreaks caused a reported 11 425 cases and 264 deaths in Kenya. Data were available from 44 districts for 6893 (60%) cases. District CFRs ranged from 0% to 14.3%. Surveyed household respondents (n = 240) were aware of cholera (97.5%) and oral rehydration solution (ORS) (87.9%). Cholera deaths were reported more frequently from East Pokot (n = 120) than Turkana South (n = 120) households (20.7% vs. 12.3%). The average travel time to a HF was 31 hours in East Pokot compared with 2 hours in Turkana South. Fewer respondents in East Pokot (9.8%) than in Turkana South (33.9%) stated that ORS was available in their village. ORS or intravenous fluid shortages occurred in 20 (76.9%) surveyed HFs. CONCLUSIONS: High CFRs in Kenya are related to healthcare access disparities, including availability of rehydration supplies.

Comparison of Tuberculin Skin Testing and Interferon-γ Release Assays in Predicting Tuberculosis Disease.

Importance: Elimination of tuberculosis (TB) disease in the US hinges on the ability of tests to detect individual risk of developing disease to inform prevention. The relative performance of 3 available TB tests-the tuberculin skin test (TST) and 2 interferon-γ release assays (IGRAs; QuantiFERON-TB Gold In-Tube [QFT-GIT] and SPOT.TB [TSPOT])-in predicting TB disease development in the US remains unknown. Objective: To compare the performance of the TST with the QFT-GIT and TSPOT IGRAs in predicting TB disease in high-risk populations. Design, Setting, and Participants: This prospective diagnostic study included participants at high risk of TB infection (TBI) or progression to TB disease at 10 US sites between 2012 and 2020. Participants of any age who had close contact with a case patient with infectious TB, were born in a country with medium or high TB incidence, had traveled recently to a high-incidence country, were living with HIV infection, or were from a population with a high local prevalence were enrolled from July 12, 2012, through May 5, 2017. Participants were assessed for 2 years after enrollment and through registry matches until the study end date (November 15, 2020). Data analysis was performed in June 2023. Exposures: At enrollment, participants were concurrently tested with 2 IGRAs (QFT-GIT from Qiagen and TSPOT from Oxford Immunotec) and the TST. Participants were classified as case patients with incident TB disease when diagnosed more than 30 days from enrollment. Main Outcomes and Measures: Estimated positive predictive value (PPV) ratios from generalized estimating equation models were used to compare test performance in predicting incident TB. Incremental changes in PPV were estimated to determine whether predictive performance significantly improved with the addition of a second test. Case patients with prevalent TB were examined in sensitivity analysis. Results: A total of 22 020 eligible participants were included in this study. Their median age was 32 (range, 0-102) years, more than half (51.2%) were male, and the median follow-up was 6.4 (range, 0.2-8.3) years. Most participants (82.0%) were born outside the US, and 9.6% were close contacts. Tuberculosis disease was identified in 129 case patients (0.6%): 42 (0.2%) had incident TB and 87 (0.4%) had prevalent TB. The TSPOT and QFT-GIT assays performed significantly better than the TST (PPV ratio, 1.65 [95% CI, 1.35-2.02] and 1.47 [95% CI, 1.22-1.77], respectively). The incremental gain in PPV, given a positive TST result, was statistically significant for positive QFT-GIT and TSPOT results (1.64 [95% CI, 1.40-1.93] and 1.94 [95% CI, 1.65-2.27], respectively). Conclusions and Relevance: In this diagnostic study assessing predictive value, IGRAs demonstrated superior performance for predicting incident TB compared with the TST. Interferon-γ release assays provided a statistically significant incremental improvement in PPV when a positive TST result was known. These findings suggest that IGRA performance may enhance decisions to treat TBI and prevent TB.

Attribution of foodborne illnesses, hospitalizations, and deaths to food commodities by using outbreak data, United States, 1998-2008.

Each year, >9 million foodborne illnesses are estimated to be caused by major pathogens acquired in the United States. Preventing these illnesses is challenging because resources are limited and linking individual illnesses to a particular food is rarely possible except during an outbreak. We developed a method of attributing illnesses to food commodities that uses data from outbreaks associated with both simple and complex foods. Using data from outbreak-associated illnesses for 1998-2008, we estimated annual US foodborne illnesses, hospitalizations, and deaths attributable to each of 17 food commodities. We attributed 46% of illnesses to produce and found that more deaths were attributed to poultry than to any other commodity. To the extent that these estimates reflect the commodities causing all foodborne illness, they indicate that efforts are particularly needed to prevent contamination of produce and poultry. Methods to incorporate data from other sources are needed to improve attribution estimates for some commodities and agents.

Sustained improvements in handwashing indicators more than 5 years after a cluster-randomised, community-based trial of handwashing promotion in Karachi, Pakistan.

OBJECTIVE: To evaluate handwashing behaviour 5 years after a handwashing intervention in Karachi, Pakistan. METHODS: In 2003, we randomised neighbourhoods to control, handwashing promotion, or handwashing promotion and water treatment. Intervention households were given soap +/- water treatment product and weekly handwashing education for 9 months. In 2009, we re-enrolled 461 households from the three study groups: control (160), handwashing (141), and handwashing + water treatment (160) and assessed hygiene-related outcomes, accounting for clustering. RESULTS: Intervention households were 3.4 times more likely than controls to have soap at their handwashing stations during the study visit [293/301 (97%) vs. 45/159 (28%), P < 0.0001]. While nearly all households reported handwashing after toileting, intervention households more commonly reported handwashing before cooking [relative risk (RR) 1.2 (95% confidence interval (CI) 1.0-1.4)] and before meals [RR 1.7 (95% CI, 1.3-2.1)]. Control households cited a mean of 3.87 occasions for washing hands; handwashing households, 4.74 occasions; and handwashing + water treatment households, 4.78 occasions (P < 0.0001). Households reported purchasing a mean of 0.65 (control), 0.91 (handwashing) and 1.1 (handwashing + water treatment) bars of soap/person/month (P < 0.0001). CONCLUSIONS: Five years after receiving handwashing promotion, intervention households were more likely to have soap at the household handwashing station, know key times to wash hands and report purchasing more soap than controls, suggesting habituation of improved handwashing practices in this population. Intensive handwashing promotion may be an effective strategy for habituating hygiene behaviours and improving health.

Using Electronic Health Record Data to Measure the Latent Tuberculosis Infection Care Cascade in Safety-Net Primary Care Clinics.

Introduction: Prevention of tuberculosis disease through diagnosis and treatment of latent tuberculosis infection is critical for achieving tuberculosis elimination in the U.S. Diagnosis and treatment of latent tuberculosis infection in safety-net primary care settings that serve patients at risk for tuberculosis may increase uptake of this prevention effort and accelerate progress toward elimination. Optimizing tuberculosis prevention in these settings requires measuring the latent tuberculosis infection care cascade (testing, diagnosis, and treatment) and identifying gaps to develop solutions to overcome barriers. We used electronic health record data to describe the latent tuberculosis infection care cascade and identify gaps among a network of safety-net primary care clinics. Methods: Electronic health record data for patients seen in the OCHIN Clinical Network, the largest network of safety-net clinics in the U.S., between 2012 and 2019 were extracted. electronic health record data were used to measure the latent tuberculosis infection care cascade: patients who met tuberculosis screening criteria on the basis of current recommendations were tested for tuberculosis infection, diagnosed with latent tuberculosis infection, and prescribed treatment for latent tuberculosis infection. Outcomes were stratified by diagnostic test and treatment regimen. Results: Among 1.9 million patients in the analytic cohort, 43.5% met tuberculosis screening criteria, but only 21.4% were tested for latent tuberculosis infection; less than half (40.4%) were tested using an interferon-gamma release assay. Among those with a valid result, 10.5% were diagnosed with latent tuberculosis infection, 29.1% of those were prescribed latent tuberculosis infection treatment, and only 33.6% were prescribed a recommended rifamycin-based regimen. Conclusions: Electronic health record data can be used to measure the latent tuberculosis infection care cascade. A large proportion of patients in this safety-net clinical network are at high risk for tuberculosis infection. Addressing identified gaps in latent tuberculosis infection testing and treatment may have a direct impact on improving tuberculosis prevention in primary care clinics and accelerate progress toward elimination.

Mumps vaccine effectiveness of a 3rd dose of measles, mumps, rubella vaccine in school settings during a mumps outbreak -- Arkansas, 2016-2017.

Objectives: The largest mumps outbreak in the United States since 2006 occurred in Arkansas during the 2016-17 school year. An additional dose (third dose) of measles-mumps-rubella vaccine (MMR3) was offered to school children. We evaluated the vaccine effectiveness (VE) of MMR3 compared with two doses of MMR for preventing mumps among school-aged children during the outbreak. Study design: A generalized linear mixed effects model was used to estimate the incremental vaccine effectiveness (VE) of a third dose of MMR compared with two doses of MMR for preventing mumps. Methods: We obtained school enrollment, immunization status and mumps case status from school registries, Arkansas's immunization registry, and Arkansas's mumps surveillance system, respectively. We included students who previously received 2 doses of MMR in schools with ≥1 mumps case after the MMR3 clinic. We used a generalized linear mixed model to estimate VE of MMR3 compared with two doses of MMR. Results: Sixteen schools with 9272 students were included in the analysis. Incremental VE of MMR3 versus a two-dose MMR regimen was 52.7% (95% confidence interval [CI]: -3.6%‒78.4%) overall and in 8 schools with high mumps transmission it was 64.0% (95% CI: 1.2%‒86.9%). MMR3 VE was higher among middle compared with elementary school students (68.5% [95% CI: -30.2%‒92.4%] vs 37.6% [95% CI: -62.5%‒76.1%]); these differences were not statistically significant. Conclusion: Our findings suggest MMR3 provided additional protection from mumps compared with two MMR doses in elementary and middle school settings during a mumps outbreak.

Nonpasteurized dairy products, disease outbreaks, and state laws-United States, 1993-2006.

Although pasteurization eliminates pathogens and consumption of nonpasteurized dairy products is uncommon, dairy-associated disease outbreaks continue to occur. To determine the association of outbreaks caused by nonpasteurized dairy products with state laws regarding sale of these products, we reviewed dairy-associated outbreaks during 1993-2006. We found 121 outbreaks for which the product's pasteurization status was known; among these, 73 (60%) involved nonpasteurized products and resulted in 1,571 cases, 202 hospitalizations, and 2 deaths. A total of 55 (75%) outbreaks occurred in 21 states that permitted sale of nonpasteurized products; incidence of nonpasteurized product-associated outbreaks was higher in these states. Nonpasteurized products caused a disproportionate number (≈150× greater/unit of product consumed) of outbreaks and outbreak-associated illnesses and also disproportionately affected persons <20 years of age. States that restricted sale of nonpasteurized products had fewer outbreaks and illnesses; stronger restrictions and enforcement should be considered.

Epidemiology of seafood-associated infections in the United States.

Seafood is part of a healthful diet, but seafood consumption is not risk-free. Seafood is responsible for an important proportion of food-borne illnesses and outbreaks in the United States. Seafood-associated infections are caused by a variety of bacteria, viruses, and parasites; this diverse group of pathogens results in a wide variety of clinical syndromes, each with its own epidemiology. Some seafood commodities are inherently more risky than others, owing to many factors, including the nature of the environment from which they come, their mode of feeding, the season during which they are harvested, and how they are prepared and served. Prevention of seafood-associated infections requires an understanding not only of the etiologic agents and seafood commodities associated with illness but also of the mechanisms of contamination that are amenable to control. Defining these problem areas, which relies on surveillance of seafood-associated infections through outbreak and case reporting, can lead to targeted research and help to guide control efforts. Coordinated efforts are necessary to further reduce the risk of seafood-associated illnesses. Continued surveillance will be important to assess the effectiveness of current and future prevention strategies.

Variability of interferon-γ release assays in people at high risk of tuberculosis infection or progression to tuberculosis disease living in the United States.

OBJECTIVES: Interferon-γ release assays, including T-SPOT.TB (TSPOT) and QuantiFERON Gold In-Tube (QFT), are important diagnostic tools for tuberculosis infection, but little work has been done to study the performance of these tests in populations prioritized for tuberculosis testing in the United States, especially those other than health care personnel. METHODS: Participants were enrolled as part of a large, prospective cohort of people at high risk of tuberculosis infection or progression to tuberculosis disease. All participants were administered a tuberculin skin test, TSPOT, and QFT test. A subset of participants had their QFT (n = 919) and TSPOT (n = 885) tests repeated when they returned to get their tuberculin skin test read 2 to 3 days later (repeat study). A total of 531 participants had a TSPOT performed twice on the same sample taken at the same time (split study). RESULTS: The QFT repeat test interpretations were discordant (one test positive and the other negative) for 6.4% of participants (59 of 919), and the TSPOT tests were discordant for 60 of 885 participants in the repeat study (6.8%) and 41 of 531 participants in the split study (7.7%). There was a high degree of variability in the quantitative test results for both QFT and TSPOT, and discordance was not associated with both test results being near the established cut-offs. Furthermore, the proportion of discordance was similar when comparing participants in both the TSPOT repeat and TSPOT split studies. DISCUSSION: Both QFT and TSPOT were 6% to 8% discordant. The results should be interpreted with caution, particularly when seeing a conversion or reversion in serial testing.

Risk factors early in the 2010 cholera epidemic, Haiti.

During the early weeks of the cholera outbreak that began in Haiti in October 2010, we conducted a case-control study to identify risk factors. Drinking treated water was strongly protective against illness. Our results highlight the effectiveness of safe water in cholera control.

Epidemic cholera in a crowded urban environment, Port-au-Prince, Haiti.

We conducted a case-control study to investigate factors associated with epidemic cholera. Water treatment and handwashing may have been protective, highlighting the need for personal hygiene for cholera prevention in contaminated urban environments. We also found a diverse diet, a possible proxy for improved nutrition, was protective against cholera.