An influenza A (H3N2) virus outbreak in the Kingdom of Cambodia during the COVID-19 pandemic of 2020.

BACKGROUND: Global influenza virus circulation decreased during the COVID-19 pandemic, possibly due to widespread community mitigation measures. Cambodia eased some COVID-19 mitigation measures in June and July 2020. On 20 August a cluster of respiratory illnesses occurred among residents of a pagoda, including people who tested positive for influenza A but none who were positive for SARS-CoV-2. METHODS: A response team was deployed on 25 August 2020. People with influenza-like illness (ILI) were asked questions regarding demographics, illness, personal prevention measures, and residential arrangements. Respiratory swabs were tested for influenza and SARS-Cov-2 by real-time reverse transcription PCR, and viruses were sequenced. Sentinel surveillance data were analyzed to assess recent trends in influenza circulation in the community. RESULTS: Influenza A (H3N2) viruses were identified during sentinel surveillance in Cambodia in July 2020 prior to the reported pagoda outbreak. Among the 362 pagoda residents, 73 (20.2%) ILI cases were identified and 40 were tested, where 33/40 (82.5%) confirmed positive for influenza A (H3N2). All 40 were negative for SARS-CoV-2. Among the 73 residents with ILI, none were vaccinated against influenza, 47 (64%) clustered in 3/8 sleeping quarters, 20 (27%) reported often wearing a mask, 27 (36%) reported often washing hands, and 11 (15%) reported practicing social distancing. All viruses clustered within clade 3c2.A1 close to strains circulating in Australia in 2020. CONCLUSIONS: Circulation of influenza viruses began in the community following the relaxation of national COVID-19 mitigation measures, and prior to the outbreak in a pagoda with limited social distancing. Continued surveillance and influenza vaccination are required to limit the impact of influenza globally.

Predictors of discordant tuberculin skin test and QuantiFERON®-TB Gold In-Tube results in various high-risk groups.

SETTING: Persons in whom targeted testing for latent tuberculosis infection (LTBI) is recommended in Seattle, Washington; Atlanta, Georgia; and central North Carolina, United States. OBJECTIVE: To compare the performance of an interferon-gamma release assay (QuantiFERON®-TB Gold In-Tube [QFT-GIT]) with the tuberculin skin test (TST) among foreign-born, homeless, human immunodeficiency virus (HIV) infected and substance abuse persons tested for LTBI. DESIGN: A cross-sectional study requiring participants to have a blood test, a TST and data collected. RESULTS: Of 1653 persons, 19.5% were TST-positive and 14.0% were QFT-GIT-positive. Overall concordance was moderate (kappa 0.53; 95%CI 0.47-0.58). Compared to concordant positive results, TST+/QFT-GIT- discordance was associated with HIV infection and sex, while TST-/QFT-GIT+ discordance was associated with HIV and inversely associated with foreign birth. Compared to concordant negative results, TST-/QFT-GIT+ discordance was associated with foreign birth and age ≥50 years, while TST+/QFT-GIT-discordance was associated with foreign birth, age 30-49 years, being Black and inversely associated with HIV. HIV infection was significantly associated with indeterminate QFT-GIT results. CONCLUSION: QFT-GIT may be an improvement over the TST for diagnosing LTBI in foreign-born and older persons, and may be as useful as the TST in HIV-infected persons. The sensitivity of both tests may be low in HIV-infected persons.

Indoor respirable particulate matter concentrations from an open fire, improved cookstove, and LPG/open fire combination in a rural Guatemalan community.

Improved biomass cookstoves have the potential to reduce pollutant emissions and thereby reduce pollution exposure among populations in developing countries who cook daily with biomass fuels. However, evaluation of such interventions has been very limited. This article presents results from a study carried out in 30 households in rural Guatemala. Twenty-four hour PM3.5 concentrations were compared over 8 months for three fuel/cookstove conditions (n = 10 households for each condition): a traditional open fire cookstove, an improved cookstove called the plancha mejorada, and a liquefied petroleum gas (LPG) stove/open fire combination. Twenty-four hour geometric mean PM3.5 concentrations were 1560 micrograms/m3 (n = 58; 95% C.I. 1310, 1850), 280 micrograms/m3 (n = 59; 95% C.I. 240-320), and 850 micrograms/m3 (n = 60; 95% C.I. 680-1050) for the open fire, plancha, and LPG/open fire combination, respectively. A generalized estimating equation model showed a 45% reduction in PM3.5 concentrations for the LPG/open fire combination as compared to the open fire alone. The difference approached significance (p < 0.0737). The plancha showed an 85% reduction in PM3.5 concentrations as compared to the open fire (p < 0.0001). An analysis of the interaction of time with stove type showed that the temporal trend in pollution did not significantly differ among the three stove types. The reduced PM3.5 concentrations were maintained over time. Season did not affect pollutant concentrations. Of the two interventions, the plancha appears to offer the best prospects for achieving substantial reductions in indoor air pollution levels, although issues of cost and stove maintenance remain to be addressed.

Indoor air pollution in developing countries: a major environmental and public health challenge.

Around 50% of people, almost all in developing countries, rely on coal and biomass in the form of wood, dung and crop residues for domestic energy. These materials are typically burnt in simple stoves with very incomplete combustion. Consequently, women and young children are exposed to high levels of indoor air pollution every day. There is consistent evidence that indoor air pollution increases the risk of chronic obstructive pulmonary disease and of acute respiratory infections in childhood, the most important cause of death among children under 5 years of age in developing countries. Evidence also exists of associations with low birth weight, increased infant and perinatal mortality, pulmonary tuberculosis, nasopharyngeal and laryngeal cancer, cataract, and, specifically in respect of the use of coal, with lung cancer. Conflicting evidence exists with regard to asthma. All studies are observational and very few have measured exposure directly, while a substantial proportion have not dealt with confounding. As a result, risk estimates are poorly quantified and may be biased. Exposure to indoor air pollution may be responsible for nearly 2 million excess deaths in developing countries and for some 4% of the global burden of disease. Indoor air pollution is a major global public health threat requiring greatly increased efforts in the areas of research and policy-making. Research on its health effects should be strengthened, particularly in relation to tuberculosis and acute lower respiratory infections. A more systematic approach to the development and evaluation of interventions is desirable, with clearer recognition of the interrelationships between poverty and dependence on polluting fuels.

Co-occurrence of nutrition problems in Honduran children.

We used data from the 1996 Honduras National Micronutrient Survey to investigate the co-occurrence of vitamin A deficiency (VAD), anemia and stunting in a representative sample of Honduran children 1-5 y old. Observed frequencies of co-occurrence were compared with frequencies expected by chance in children 12-35.9 mo old (n = 633) and 36-59.9 mo old (n = 610) for the three possible two-way combinations of the problems and the three-way combination. Observed frequencies were greater than expected frequencies for all eight comparisons, and all comparisons except for that of stunting and anemia in younger children were significant. The observed frequency of the three-way co-occurrence was 8.4% compared with an expected co-occurrence of 8.1% in younger children (P: < 0.05) and 4.8% compared with 4.2%, respectively, in older children (P: < 0.001). Although there was statistical evidence for co-occurrence, differences between expected and observed prevalences were small for most comparisons. Our findings suggest that having one or two problems does not appreciably increase the probability of having another. The efficiency of nutrition interventions aimed at these conditions would not be improved by targeting children with any one of the conditions; rather, the three conditions should be treated as virtually independent when designing programs. Replication of this study in other settings is warranted.

Domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian villages.

BACKGROUND: Chronic bronchitis is an important public health problem worldwide. A study was undertaken to examine the association between exposure to air pollution from domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian highland villages: a village in which cooking is done exclusively indoors and a village in which cooking is done primarily outdoors. Apart from this difference, the villages were virtually identical in terms of socioeconomic status, climate, altitude, access to health care, and other potential confounders. METHODS: Pollution exposure was assessed by combining information on concentrations of particulate matter of <10 microm diameter (PM(10)) in 12 randomly selected households in each village in all potential microenvironments of exposure with time allocation information. The prevalence of chronic bronchitis was assessed using the British Medical Research Council's questionnaire on individuals >20 years of age in both villages (n = 241). RESULTS: Daily pollution exposure was significantly higher in the indoor cooking village (range for adults: 9840-15 120 microg-h/m(3)) than in the outdoor cooking village (range for adults: 5520-6240 microg-h/m(3)) for both seasons and for men and women. The overall prevalence of chronic bronchitis was 22% and 13% for the indoor and outdoor cooking villages, respectively. Logistic regression analysis, which excluded the few smokers present in the population, showed a 60% reduced risk of chronic bronchitis in the outdoor cooking village compared with the indoor cooking village (OR 0.4; 95% CI 0.2 to 0.8; p = 0.0102) after adjusting for age and sex. Individuals aged >40 years were 4.3 times more likely to have chronic bronchitis than the younger age group (OR = 4.3; 95% CI 2.0 to 9.3; p = 0.0002). There was no significant difference in the prevalence of chronic bronchitis in men and women. CONCLUSIONS: The results of this study suggest an association between chronic bronchitis and exposure to domestic biomass fuel combustion, but further large scale studies from other areas of the developing world are needed to confirm the association. Results from this and other studies will assist the development of culturally acceptable and feasible alternatives to the high exposure cooking stoves currently being used by most people worldwide.

Developmental, genetic, and environmental components of aerobic capacity at high altitude.

The aerobic capacity of 268 subjects (158 males and 110 females) was evaluated in La Paz, Bolivia situated at 3,750 m. The sample included 1) 39 high altitude rural natives (all male); 2) 67 high altitude urban natives (32 male, 35 female); 3) 69 Bolivians of foreign ancestry acclimatized to high altitude since birth (37 male, 32 female); 4) 50 Bolivians of foreign ancestry acclimatized to high altitude during growth (25 male, 25 female); and 5) 42 non-Bolivians of either European or North American ancestry acclimatized to high altitude during adulthood (25 male, 18 female). Data analyses indicate that 1) high altitude urban natives, acclimatized to high altitude since birth or during growth, attained higher aerobic capacity than subjects acclimatized to high altitude during adulthood; 2) age at arrival to high altitude is inversely related to maximum oxygen consumption (VO2 max) expressed in terms L/min or ml/min/kg of lean body mass, but not in terms of ml/min/kg of body weight; 3) among subjects acclimatized to high altitude during growth, approximately 25% of the variability in aerobic capacity can be explained by developmental factors; 4) as inferred from evaluations of skin color reflectance and sibling similarities, approximately 20 to 25% of the variability in aerobic capacity at high altitude can be explained by genetic factors; 5) except among the non-Bolivians acclimatized to high altitude during adulthood, the aerobic capacity of individuals with high occupational activity level is equal to the aerobic capacity of high altitude rural natives; and 6) the relationship between occupational activity level and aerobic capacity is much greater among subjects acclimatized to high altitude before the age of 10 years than afterwards. Together these data suggest that the attainment of normal aerobic capacity at high altitude is related to both developmental acclimatization and genetic factors but its expression is highly mediated by environmental factors, such as occupational activity level and body composition.