Acute intoxication from carbon monoxide (CO) has been reported to contribute to more than 2000 poisoning deaths annually in the United States.^1-4 Common sources of CO poisoning include the operation of motor vehicles in enclosed or semi-enclosed areas, malfunctioning home heating systems, and improperly vented combustion appliances.^2,5 Even in outdoor environments, combustion engine exhaust can produce localized concentrations of CO that are capable of producing unconsciousness and death in minutes.^6,7

To assess the health effects of exposure to smoke from the fifth largest US wildfire of 1999 and to evaluate whether participation in interventions to reduce smoke exposure prevented adverse lower respiratory tract health effects among residents of the Hoopa Valley National Indian Reservation in northwestern California. Observational study: epidemiologists from the Centers for Disease Control and Prevention retrospectively reviewed medical records at the local medical center and conducted survey interviews of reservation residents. Humboldt County, California. Interviews were completed with 289 of 385 residents, representing 26% of the households on the reservation. Of the 289 participants, 92 (31.8%) had preexisting cardiopulmonary conditions. During the weeks of the forest fire, medical visits for respiratory illnesses increased by 217 visits (from 417 to 634 visits, or by 52%) over the previous year. Survey results indicated that although 181 (62.6%) of 289 participants reported worsening lower respiratory tract symptoms, those with preexisting cardiopulmonary conditions reported more symptoms before, during, and after the smoke episode. An increased duration of the use of high-efficiency particulate air cleaners and the recollection of public service announcements were associated with a reduced odds of reporting adverse health effects of the lower respiratory tract. No protective effects were observed for duration of mask use or evacuation. Timely actions undertaken by the clinical staff of the local medical center appeared beneficial to the respiratory health of the community. Future programs that reduce economic barriers to evacuation during smoke episodes may also improve intervention participation rates and decrease smoke exposures. Although promising, the effectiveness of these and other interventions need to be confirmed in a prospective community intervention trial.

In Kenya, detailed data on the age-specific burden of influenza and RSV are essential to inform use of limited vaccination and treatment resources. We analyzed surveillance data from August 2009 to July 2012 for hospitalized severe acute respiratory illness (SARI) and outpatient influenza-like illness (ILI) at two health facilities in western Kenya to estimate the burden of influenza and respiratory syncytial virus (RSV). Incidence rates were estimated by dividing the number of cases with laboratory-confirmed virus infections by the mid-year population. Rates were adjusted for healthcare-seeking behavior, and to account for patients who met the SARI/ILI case definitions but were not tested. The average annual incidence of influenza-associated SARI hospitalization per 1,000 persons was 2.7 (95% CI 1.8–3.9) among children <5 years and 0.3 (95% CI 0.2–0.4) among persons ≥5 years; for RSV-associated SARI hospitalization, it was 5.2 (95% CI 4.0–6.8) among children <5 years and 0.1 (95% CI 0.0–0.2) among persons ≥5 years. The incidence of influenza-associated medically-attended ILI per 1,000 was 24.0 (95% CI 16.6–34.7) among children <5 years and 3.8 (95% CI 2.6–5.7) among persons ≥5 years. The incidence of RSV-associated medically-attended ILI was 24.6 (95% CI 17.0–35.4) among children <5 years and 0.8 (95% CI 0.3–1.9) among persons ≥5 years. Influenza and RSV both exact an important burden in children. This highlights the possible value of influenza vaccines, and future RSV vaccines, for Kenyan children.

Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases). For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity. The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries’ geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play. These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

Reducing acute respiratory infection burden in children in Africa remains a major priority and challenge. We analyzed data from population-based infectious disease surveillance for severe acute respiratory illness (SARI) among children <5 years of age in Kibera, a densely populated urban slum in Nairobi, Kenya. Surveillance was conducted among a monthly mean of 5,874 (range = 5,778-6,411) children <5 years old in two contiguous villages in Kibera. Participants had free access to the study clinic and their health events and utilization were noted during biweekly home visits. Patients meeting criteria for SARI (WHO-defined severe or very severe pneumonia, or oxygen saturation 20% additional cases. Influenza viruses and RSV (and possibly PIV, hMPV and adenoviruses) are important pathogens to consider when developing technologies and formulating strategies to treat and prevent SARI in children.