Epidemiology and Treatment Outcomes of Tuberculosis with Chronic Hepatitis B Infection-California, 2016-2020.

BACKGROUND: Improved epidemiologic and treatment data for active tuberculosis (TB) with chronic hepatitis B virus (cHBV) infection might inform and encourage screening and vaccination programs focused on persons at risk of having both conditions. METHODS: We matched the California Department of Public Health TB registry during 2016-2020 to the cHBV registry using probabilistic matching algorithms. We used chi-square analysis to compare the characteristics of persons with TB and cHBV with those with TB only. We compared TB treatment outcomes between these groups using modified Poisson regression models. We calculated the time between reporting of TB and cHBV diagnoses for those with both conditions. RESULTS: We identified 8,435 persons with TB, including 316 (3.7%) with cHBV.- Among persons with TB and cHBV, 256 (81.0%) were non-U.S.-born Asian vs 4,186 (51.6%) with TB only (P <0.0001). End-stage renal disease (26 [8.2%] vs 322 [4.0%]; P <0.001) and HIV (21 [6.7%] vs 247 [3.0%]; P value = 0.02) were more frequent among those with TB and cHBV compared with those with TB only. Among those with both conditions, 35 (11.1%) had TB diagnosed >60 days before cHBV (median 363 days) and 220 (69.6%) had TB diagnosed >60 days after cHBV (median 3,411 days). CONCLUSION: Persons with TB and cHBV were found more frequently in certain groups compared with TB only, and infrequently had their conditions diagnosed together. This highlights an opportunity to improve screening and treatment of TB and cHBV in those at high risk for coinfection.

Second and Third Trimester Fetal Death in the Setting of COVID-19: A California 2020 Case Series.

Maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the second and third trimesters of pregnancy may impact fetal development via vertical transmission, complications of coronavirus disease 2019 (COVID-19), or placental injury. However, potential associations between prenatal SARS-CoV-2 infection and fetal loss are not well understood. This case series of thirteen second and third trimester fetal losses reported by local public health departments to California's state public health surveillance included maternal clinical and demographic characteristics as well as placental pathology, fetal autopsy reports, and coroner report. There was no evidence that maternal COVID-19 disease severity, placental injury, or SARS-CoV-2 vertical transmission contributed to pregnancy loss. However, this case series is a limited sample; more research is needed to identify factors of prenatal SARS-CoV-2 that may contribute to fetal death in the second and third trimesters.

Disparities in risk perception and low harm reduction services awareness, access, and utilization among young people with newly reported hepatitis C infections in California, 2018.

BACKGROUND: Newly reported hepatitis C virus (HCV) infections in California increased 50% among people 15-29 years of age between 2014 and 2016. National estimates suggest this increase was due to the opioid epidemic and associated increases in injection drug use. However, most of California's 61 local health jurisdictions (LHJs) do not routinely investigate newly reported HCV infections, so these individuals' risk factors for infection are not well understood. We sought to describe the demographics, risk behaviors, and utilization of harm reduction services in California's fastest-rising age group of people with newly reported hepatitis C infections to support targeted HCV prevention and treatment strategies. METHODS: California Department of Public Health invited LHJs to participate in enhanced surveillance if they met criteria indicating heightened population risk for HCV infection among people ages 15-29. From June-December 2018, eight LHJs contacted newly reported HCV cases by phone using a structured questionnaire. RESULTS: Among 472 total HCV cases who met the inclusion criteria, 114 (24%) completed an interview. Twenty-seven percent of respondents (n = 31) had ever been incarcerated, of whom 29% received a tattoo/piercing and 39% injected drugs while incarcerated. Among people who injected drugs (PWID)-36% (n = 41) of all respondents-68% shared injection equipment and many lacked access to harm reduction services: 37% knew of or ever used a needle exchange and 44% ever needed naloxone during an overdose but did not have it. Heroin was the most frequently reported injected drug (n = 30), followed by methamphetamine (n = 18). Pre-diagnosis HCV risk perception varied significantly by PWID status and race/ethnicity: 76% of PWID vs. 8% of non-PWID (p < 0.001), and 44% of non-Hispanic White respondents vs. 22% of people of color (POC) respondents (p = 0.011), reported thinking they were at risk for HCV before diagnosis. Eighty-nine percent of all respondents reported having health insurance, although only two had taken HCV antiviral medications. CONCLUSIONS: Among young people with HCV, we found limited pre-diagnosis HCV risk perception and access to harm reduction services, with racial/ethnic disparities. Interventions to increase harm reduction services awareness, access, and utilization among young PWID, especially young PWID of color, may be warranted.

Molecular Epidemiology of Measles in California, United States-2019.

In 2019, the United States (US) experienced the highest number of measles importations and cases in the postelimination era. More than a quarter of imported cases entered the US through California. Measles surveillance efforts in California resulted in the identification of 26 importations, 6 outbreaks, and 72 cases in 2019. Only genotype B3 and D8 measles strains were detected. Genotype-specific differences were noted in the incidence of vaccine failures, hospitalizations, and severe complications among cases. A targeted whole genome sequencing approach provided higher-resolution discrimination between epidemiologically linked and sporadically introduced strains than conventional N450 sequencing. Our report underscores the importance of ensuring appropriate measles vaccination status, especially prior to international travel to measles-endemic regions, and highlights the value of a strong measles surveillance system in minimizing outbreaks and preserving measles elimination status in the US.

Public Health Responses to COVID-19 Outbreaks on Cruise Ships - Worldwide, February-March 2020.

An estimated 30 million passengers are transported on 272 cruise ships worldwide each year* (1). Cruise ships bring diverse populations into proximity for many days, facilitating transmission of respiratory illness (2). SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) was first identified in Wuhan, China, in December 2019 and has since spread worldwide to at least 187 countries and territories. Widespread COVID-19 transmission on cruise ships has been reported as well (3). Passengers on certain cruise ship voyages might be aged ≥65 years, which places them at greater risk for severe consequences of SARS-CoV-2 infection (4). During February-March 2020, COVID-19 outbreaks associated with three cruise ship voyages have caused more than 800 laboratory-confirmed cases among passengers and crew, including 10 deaths. Transmission occurred across multiple voyages of several ships. This report describes public health responses to COVID-19 outbreaks on these ships. COVID-19 on cruise ships poses a risk for rapid spread of disease, causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread. All persons should defer all cruise travel worldwide during the COVID-19 pandemic.

Estimates of Prenatal HIV, Hepatitis B Virus, and Hepatitis C Virus Testing Among Pregnant People Enrolled in Wisconsin Medicaid, 2011-2015.

BACKGROUND: The opioid epidemic and rising rates of injection drug use are increasing the risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections among pregnant people. According to national clinical guidelines, pregnant people should be universally tested for HIV and HBV, and risk-based tested for HCV. The aim of this study was to determine the proportion and characteristics of prenatal HIV, HBV, and HCV testing and diagnosis among pregnant people with Wisconsin Medicaid coverage between 2011 and 2015. METHODS: Wisconsin birth certificates and Medicaid enrollment data were used to identify the sample. Standard billing and diagnosis codes were used to assess study variables. Data for each pregnancy were analyzed to describe the proportion of pregnancies that had evidence of testing, diagnoses, and yearly trends. RESULTS: Of the 78,917 pregnancies, prenatal testing estimates were 67% for HIV, 73% for HBV, and 6% for HCV. The estimated rate of infections during the study period was 1.82 for HIV, 2.09 for HBV, and 3.52 for HCV per 1000 pregnancies. Compared to the other race/ethnicity groups, pregnant people who were Black were most likely to be tested for HIV (78%) and HBV (80%), and pregnant people who were White were most likely to be tested for HCV (7%). CONCLUSIONS: Clinical testing guidelines have not been effectively translated to practice. Additionally, compared to HIV and HBV, HCV infections during pregnancy are becoming more prevalent, yet current national HCV screening guidelines are the least comprehensive.

Linking HIV and Viral Hepatitis Surveillance Data: Evaluating a Standard, Deterministic Matching Algorithm Using Data From 6 US Health Jurisdictions.

Accurate interpretations and comparisons of record linkage results across jurisdictions require valid and reliable matching methods. We compared existing matching methods used by 6 US state and local health departments (Houston, Texas; Louisiana; Michigan; New York, New York; North Dakota; and Wisconsin) to link human immunodeficiency virus and viral hepatitis surveillance data with a 14-key automated, hierarchical deterministic matching method. Applicable years of study varied by disease and jurisdiction, ranging from 1979 to 2016. We calculated percentage agreement and Cohen's κ coefficient to compare the matching methods used within each jurisdiction. We calculated sensitivity, specificity, and positive predictive value for each matching method, as compared with a new standard that included manual review of discrepant cases. Agreement between the existing matching method and the deterministic matching method was 99.6% or higher in all jurisdictions; Cohen's κ values ranged from 0.87 to 0.98. The sensitivity of the deterministic matching method ranged from 97.4% to 100% in the 6 jurisdictions; specificity ranged from 99.7% to 100%; and positive predictive value ranged from 97.4% to 100%. Although no gold standard exists, prior assessments of existing methods and review of discrepant classifications suggest good accuracy and reliability of our deterministic matching method, with the advantage that our method reduces the need for manual review and allows for standard comparisons across jurisdictions when linking human immunodeficiency virus and viral hepatitis data.

The continuum of hepatitis C care for criminal justice involved adults in the DAA era: a retrospective cohort study demonstrating limited treatment uptake and inconsistent linkage to community-based care.

BACKGROUND: Incarcerated populations are disproportionately burdened by hepatitis C virus (HCV) infection. The introduction of highly-effective, direct-acting antiviral (DAA) treatment has potential to substantially reduce the burden of liver disease in this population, but accurate information about access to and utilization of this treatment is currently limited. The goals of this study were to characterize receipt of HCV care and treatment services for a cohort of HCV-infected adults identified in a state prison system, and to describe the complex health needs of this population. METHODS: To estimate the proportion of patients who were treated for HCV while incarcerated, and the proportion linked to HCV care after release from prison, we used a deterministic matching algorithm to link administrative prison data, health care records, and a state public health surveillance database, which captures all positive HCV-related diagnostic test results through automatic laboratory reporting. Individuals not evaluated or treated for HCV while in prison were considered likely to have been linked to care in the community if the HCV surveillance system contained a record of a quantitative HCV RNA or genotype test within 6 months of their release date. Demographic and comorbidity data were manually extracted from the electronic health records for all patients referred for consideration of HCV treatment. RESULTS: Between 2011 and 2015, 3126 individuals were known to be living with chronic HCV infection while incarcerated in the state prison system. Of these, 570 (18%) individuals were evaluated for HCV treatment while incarcerated and 328 (10%) initiated treatment with DAAs. Of the 2556 individuals not evaluated for treatment, 1605 (63%) were released from prison during the 5 year study period. Of these, 138 (9%) individuals engaged in HCV care in the community within 6 months. Data describing medical and psychiatric co-morbidities were available for the prison-based treatment cohort, which showed a high prevalence of major depression (39%), anxiety disorder (24%), alcohol misuse (52%), cocaine use (52%) and prior injection drug use (62%). CONCLUSION: Despite HCV treatment advances, linkage to care and treatment rates for criminal-justice involved adults remains low, particularly for those who must seek care in the community after release from prison. Treating criminal-justice involved individuals for HCV during incarceration provides an opportunity to improve linkage to care and treatment rates among this vulnerable population.

Increased Risk for Mother-to-Infant Transmission of Hepatitis C Virus Among Medicaid Recipients - Wisconsin, 2011-2015.

State surveillance during the last 10 years reveals a nationwide increase in hepatitis C virus (HCV) infection among young adults (1). The proportion of infants born to HCV-infected women is also increasing nationally (2). To estimate the proportion of infants born to HCV-infected women and the frequency of confirmed HCV infection in their infants, maternal name and date of birth from HCV reports in the Wisconsin Electronic Disease Surveillance System (WEDSS) were linked to Wisconsin Medicaid data for 2011-2015 births. During this period, in the Wisconsin Medicaid population, the proportion of women who had evidence of HCV infection during pregnancy increased 93%, from 1 in 368 pregnancies to 1 in 192. Among 183 infants born to women with evidence of HCV viremia during pregnancy, 34% received recommended HCV testing (3). Mother-to-infant (vertical) transmission was documented in 4% of infants. Improvements in HCV screening practices among pregnant women and infants could enhance identification of infants at risk for vertical transmission of HCV.

Performance of Risk-Based and Birth-Cohort Strategies for Identifying Hepatitis C Virus Infection Among People Entering Prison, Wisconsin, 2014.

OBJECTIVES: The prevalence of hepatitis C virus (HCV) infection among young adults is rising in Wisconsin. We examined the prevalence of HCV infection among male and female inmates entering two Wisconsin prisons and evaluated existing and alternate risk-based strategies for identifying HCV infection at intake. METHODS: We added HCV testing to the intake procedures for all 1,239 adults prison entrants at the Wisconsin Department of Corrections (WDOC) from November 3, 2014, to January 31, 2015. We identified risk factors associated with HCV infection during the routine intake examination and calculated the sensitivity and specificity of risk-based testing strategies for identifying HCV infection. RESULTS: The prevalence of HCV antibody among prison entrants was 12.5% (95% confidence interval [CI] 10.7, 14.4) overall and was almost two times higher at the women's facility (21.3%, 95% CI 15.4, 27.2) than at the men's facility (11.0%, 95% CI 0.0, 12.9) (p<0.001). The sensitivity and specificity of the WDOC risk-based criteria were 88% (95% CI 83, 93) and 80% (95% CI 78, 83), respectively. Adding a new criterion, the 1945-1965 birth cohort, to the risk-based criteria improved the sensitivity to 92% (95% CI 88, 96) and lowered the specificity to 71% (95% CI 68, 74). Compared with entrants without these risk factors, HCV antibody prevalence was significantly higher among prison entrants who had the following risk factors: injection drug use (prevalence ratio [PR] = 9.9, 95% CI 7.4, 13.2), liver disease (PR=9.7, 95% CI 7.8, 12.0), and elevated levels of alanine transaminase (PR=3.6, 95% CI 2.7, 4.9). CONCLUSION: The WDOC risk criteria for HCV testing identified 88% of HCV infections among prison entrants. Including the 1945-1965 birth cohort as a criterion along with the other WDOC risk criteria increased the sensitivity of targeted testing to 92%. These findings may be informative to jurisdictions where universal HCV testing is not feasible because of resource limitations.

Provider Workforce Assessment in a Rural Hepatitis C Epidemic: Implications for Scale-up of Antiviral Therapy.

New recommendations for birth cohort screening for hepatitis C virus (HCV) infection and the development of new, highly effective antiviral medications are expected to increase the demand for HCV treatment. In the past, antiviral therapy for HCV was almost exclusively prescribed by specialists in the field of gastroenterology and infectious diseases, meaning that people living in rural areas that are underserved by specialists may have poor access to treatment. We investigated the number and geographic distribution of medical providers who actively prescribed direct acting antiviral drugs for hepatitis C in Wisconsin during 2012. Using public health surveillance data and a state-wide prescription drug database, we found that there was 1 treatment provider for every 340 residents known to be living with HCV. However, 51 of 72 Wisconsin counties had no providers who provided HCV treatment in 2012.Scaling up antiviral treatment to address the epidemic of hepatitis C efficiently and equitably will require strategies to increase the number of treatment providers in rural communities. Providing education, training, and support to the primary care workforce serving rural communities should be considered a potentially effective and efficient approach to preventing future HCV-related illness.

Potential barriers to healthcare in Malawi for under-five children with cough and fever: a national household survey.

Failure to access healthcare is an important contributor to child mortality in many developing countries. In a national household survey in Malawi, we explored demographic and socioeconomic barriers to healthcare for childhood illnesses and assessed the direct and indirect costs of seeking care. Using a cluster-sample design, we selected 2,697 households and interviewed 1,669 caretakers. The main reason for households not being surveyed was the absence of a primary caretaker in the household. Among 2,077 children aged less than five years, 504 episodes of cough and fever during the previous two weeks were reported. A trained healthcare provider was visited for 48.0% of illness episodes. A multivariate regression model showed that children from the poorest households (p = 0.02) and children aged > 12 months (p = 0.02) were less likely to seek care when ill compared to those living in wealthier households and children of higher age-group respectively. Families from rural households spent more time travelling compared to urban households (68.9 vs 14.1 minutes; p < 0.001). In addition, visiting a trained healthcare provider was associated with longer travel time (p < 0.001) and higher direct costs (p < 0.001) compared to visiting an untrained provider. Thus, several barriers to accessing healthcare in Malawi for childhood illnesses exist. Continued efforts to reduce these barriers are needed to narrow the gap in the health and healthcare equity in Malawi.

Rapid hepatitis C testing among persons at increased risk for infection--Wisconsin, 2012-2013.

An estimated 3.2 million persons in the United States have chronic infection with hepatitis C virus (HCV). Most new HCV transmissions occur among persons who inject drugs, often within the first few years of their injection drug use. During 2003-2012, reports of HCV infection increased from 15 to 54 cases per 100,000 among persons aged <30 years in Wisconsin, and 58% of persons in this age group with acute HCV infection reported injecting drugs (Wisconsin Division of Public Health, unpublished data, 2013). To increase detection of HCV infection, the Wisconsin Division of Public Health (WDPH) piloted a program during October 2012-October 2013 that offered rapid HCV testing to clients of four agencies providing outreach testing for HCV and human immunodeficiency virus infection, syringe exchange, counseling, and other harm reduction services to persons with drug dependence. During that period, 1,255 persons were tested using a rapid HCV test, and 246 (20%) of the results were positive. Most (72%) of the infections had not been reported to WDPH. A blood specimen for further testing was collected from 192 (78%) participants with positive HCV test results; among these participants, 183 were tested for HCV RNA using reverse transcription-polymerase chain reaction (RT-PCR), and these results were positive for 128 (70%) participants, indicating active infection. Use of the rapid HCV test detected previously unreported HCV infections and raised awareness of HCV. Persons identified with active HCV infection should be referred to medical care and counseled on ways to prevent HCV transmission to others.

Challenges to evaluating respiratory syncytial virus mortality in Bangladesh, 2004-2008.

BACKGROUND: Acute lower respiratory illness is the most common cause of death among children, globally. Data are not available to make accurate estimates on the global mortality from respiratory syncytial virus (RSV), specifically. METHODS: Respiratory samples collected from children under 5 years of age during 2004 to 2008 as part of population-based respiratory disease surveillance in an urban community in Dhaka, Bangladesh were tested for RSV, human metapneumovirus (HMPV), human parainfluenza virus (PIV) types 1, 2, and 3, influenza and adenovirus by RT-PCR. Verbal autopsy data were used to identify children who died from respiratory illness in a nearby rural community. Significance of the correlation between detections and community respiratory deaths was determined using Spearman's coefficient. RESULTS: RSV activity occurred during defined periods lasting approximately three months but with no clear seasonal pattern. There was no significant correlation between respiratory deaths and detection of any of the respiratory viruses studied. CONCLUSION: Outbreaks of respiratory viruses may not be associated with deaths in children in the study site; however, the few respiratory deaths observed and community-to-community variation in the timing of outbreaks may have obscured an association. An accurate assessment of respiratory virus-associated deaths will require detections and death data to come from the same location and a larger study population.

Comparison of fast-track diagnostics respiratory pathogens multiplex real-time RT-PCR assay with in-house singleplex assays for comprehensive detection of human respiratory viruses.

Fast-track Diagnostics respiratory pathogens (FTDRP) multiplex real-time RT-PCR assay was compared with in-house singleplex real-time RT-PCR assays for detection of 16 common respiratory viruses. The FTDRP assay correctly identified 26 diverse respiratory virus strains, 35 of 41 (85%) external quality assessment samples spiked with cultured virus and 232 of 263 (88%) archived respiratory specimens that tested positive for respiratory viruses by in-house assays. Of 308 prospectively tested respiratory specimens selected from children hospitalized with acute respiratory illness, 270 (87.7%) and 265 (86%) were positive by FTDRP and in-house assays for one or more viruses, respectively, with combined test results showing good concordance (K=0.812, 95% CI=0.786-0.838). Individual FTDRP assays for adenovirus, respiratory syncytial virus and rhinovirus showed the lowest comparative sensitivities with in-house assays, with most discrepancies occurring with specimens containing low virus loads and failed to detect some rhinovirus strains, even when abundant. The FTDRP enterovirus and human bocavirus assays appeared to be more sensitive than the in-house assays with some specimens. With the exceptions noted above, most FTDRP assays performed comparably with in-house assays for most viruses while offering enhanced throughput and easy integration by laboratories using conventional real-time PCR instrumentation.

Multidrug-resistant typhoid fever with neurologic findings on the Malawi-Mozambique border.

BACKGROUND: Salmonella enterica serovar Typhi causes an estimated 22 million cases of typhoid fever and 216 000 deaths annually worldwide. We investigated an outbreak of unexplained febrile illnesses with neurologic findings, determined to be typhoid fever, along the Malawi-Mozambique border. METHODS: The investigation included active surveillance, interviews, examinations of ill and convalescent persons, medical chart reviews, and laboratory testing. Classification as a suspected case required fever and ≥1 other finding (eg, headache or abdominal pain); a probable case required fever and a positive rapid immunoglobulin M antibody test for typhoid (TUBEX TF); a confirmed case required isolation of Salmonella Typhi from blood or stool. Isolates underwent antimicrobial susceptibility testing and subtyping by pulsed-field gel electrophoresis (PFGE). RESULTS: We identified 303 cases from 18 villages with onset during March-November 2009; 214 were suspected, 43 were probable, and 46 were confirmed cases. Forty patients presented with focal neurologic abnormalities, including a constellation of upper motor neuron signs (n = 19), ataxia (n = 22), and parkinsonism (n = 8). Eleven patients died. All 42 isolates tested were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole; 4 were also resistant to nalidixic acid. Thirty-five of 42 isolates were indistinguishable by PFGE. CONCLUSIONS: The unusual neurologic manifestations posed a diagnostic challenge that was resolved through rapid typhoid antibody testing in the field and subsequent blood culture confirmation in the Malawi national reference laboratory. Extending laboratory diagnostic capacity, including blood culture, to populations at risk for typhoid fever in Africa will improve outbreak detection, response, and clinical treatment.

Respiratory syncytial virus-associated hospitalizations among infants and young children in the United States, 1997-2006.

BACKGROUND: Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract disease among young children in the United States. RSV-associated hospitalization increased among children in the United States during 1980 through 1996. In this study, we updated national estimates of RSV hospitalization rates among US children through 2006. METHODS: We conducted a retrospective analysis of hospital discharges for lower respiratory tract illness (LRTI) in children <5 years old from the National Hospital Discharge Survey. LRTI hospitalizations were identified by using International Classification of Diseases, Ninth Revision, Clinical Modification codes. RSV-coded hospitalizations were International Classification of Diseases, Ninth Revision, Clinical Modification codes 466.11, 480.1, and 079.6. RSV-associated hospitalizations were the sum of RSV-coded hospitalizations and a proportion of hospitalizations coded as bronchiolitis and pneumonia during the RSV season. RESULTS: RSV-coded hospitalizations accounted for 24% of an estimated 5.5 million LRTI hospitalizations among children <5 years of age during the 10 study years, 1997-2006. The RSV-coded hospitalization rate in infants <1 year old was 26.0 per 1000, with no significant difference between study years. The hospitalization rate was highest among infants <3 months old (48.9 per 1000), followed by infants 3 to 5 months old (28.4 per 1000), and lower among those >1 year old (1.8 per 1000). An estimated 132,000 to 172,000 RSV-associated hospitalizations occurred annually in children <5 years of age. CONCLUSION: RSV hospitalization rates remained steady during 1997 to 2006 and were a substantial burden in the United States, especially among infants and young children. A safe and effective RSV vaccine is needed.

The effect of age on transmission of 2009 pandemic influenza A (H1N1) in a camp and associated households.

BACKGROUND: A major portion of influenza disease burden during the 2009 pandemic was observed among young people. METHODS: We examined the effect of age on the transmission of influenza-like illness associated with the 2009 pandemic influenza A (H1N1) virus (pH1N1) for an April-May 2009 outbreak among youth-camp participants and household contacts in Washington State. RESULTS: An influenza-like illness attack rate of 51% was found among 96 camp participants. We observed a cabin secondary attack rate of 42% (95% confidence interval = 21%-66%) and a camp local reproductive number of 2.7 (1.7-4.1) for influenza-like illness among children (less than 18 years old). Among the 136 contacts in the 41 households with an influenza-like illness index case who attended the camp, the influenza-like illness secondary attack rate was 11% for children (5%-21%) and 4% for adults (2%-8%). The odds ratio for influenza-like illness among children versus adults was 3.1 (1.3-7.3). CONCLUSIONS: The strong age effect, combined with the low number of susceptible children per household (1.2), plausibly explains the lower-than-expected household secondary attack rate for influenza-like illness, illustrating the importance of other venues where children congregate for sustaining community transmission. Quantifying the effects of age on pH1N1 transmission is important for informing effective intervention strategies.

Prevalence of Acanthamoeba spp. and other free-living amoebae in household water, Ohio, USA--1990-1992.

Knowledge of the prevalence of free-living amoebae (FLA) in US household water can provide a focus for prevention of amoeba-associated illnesses. Household water samples from two Ohio counties, collected and examined for amoebae during 1990-1992, were used to describe the prevalence of Acanthamoeba and other FLA in a household setting. Amoebae were isolated and identified by morphologic features. A total of 2,454 samples from 467 households were examined. Amoebae were found in water samples of 371 (79%) households. Sites most likely to contain amoeba were shower heads (52%) and kitchen sprayers (50%). Species of Hartmannella, Acanthamoeba, or Vahlkampfia were most common. Detection was higher in biofilm swab samples than in water samples. Detection of FLA and Acanthamoeba, at 79% and 51%, respectively, exceed estimates that have been published in previous surveys of household sources. We believe FLA are commonplace inhabitants of household water in this sample as they are in the environment.