Zoonotic disease emergence is not a purely biological process mediated only by ecologic factors; opportunities for transmission of zoonoses from animals to humans also depend on how people interact with animals. While exposure is conditioned by the type of animal and the location in which interactions occur, these in turn are influenced by human activity. The activities people engage in are determined by social as well as contextual factors including gender, age, socio-economic status, occupation, social norms, settlement patterns and livelihood systems, family and community dynamics, as well as national and global influences. This paper proposes an expanded "One Health" conceptual model for human-animal exposure that accounts for social as well as epidemiologic factors. The expanded model informed a new study approach to document the extent of human exposure to animals and explore the interplay of social and environmental factors that influence risk of transmission at the individual and community level. The approach includes a formative phase using qualitative and participatory methods, and a representative, random sample survey to quantify exposure to animals in a variety of settings. The paper discusses the different factors that were considered in developing the approach, including the range of animals asked about and the parameters of exposure that are included, as well as factors to be considered in local adaptation of the generic instruments. Illustrative results from research using this approach in Lao PDR are presented to demonstrate the effect of social factors on how people interact with animals. We believe that the expanded model can be similarly operationalized to explore the interactions of other social and policy-level determinants that may influence transmission of zoonoses.

Although the majority of emerging infectious diseases can be linked to wildlife sources, most pathogen spillover events to people could likely be avoided if transmission was better understood and practices adjusted to mitigate risk. Wildlife trade can facilitate zoonotic disease transmission and represents a threat to human health and economies in Asia, highlighted by the 2003 SARS coronavirus outbreak, where a Chinese wildlife market facilitated pathogen transmission. Additionally, wildlife trade poses a serious threat to biodiversity. Therefore, the combined impacts of Asian wildlife trade, sometimes termed bush meat trade, on public health and biodiversity need assessing. From 2010 to 2013, observational data were collected in Lao PDR from markets selling wildlife, including information on volume, form, species and price of wildlife; market biosafety and visitor origin. The potential for traded wildlife to host zoonotic diseases that pose a serious threat to human health was then evaluated at seven markets identified as having high volumes of trade. At the seven markets, during 21 observational surveys, 1,937 alive or fresh dead mammals (approximately 1,009 kg) were observed for sale, including mammals from 12 taxonomic families previously documented to be capable of hosting 36 zoonotic pathogens. In these seven markets, the combination of high wildlife volumes, high risk taxa for zoonoses and poor biosafety increases the potential for pathogen presence and transmission. To examine the potential conservation impact of trade in markets, we assessed the status of 33,752 animals observed during 375 visits to 93 markets, under the Lao PDR Wildlife and Aquatic Law. We observed 6,452 animals listed by Lao PDR as near extinct or threatened with extinction. The combined risks of wildlife trade in Lao PDR to human health and biodiversity highlight the need for a multi-sector approach to effectively protect public health, economic interests and biodiversity.

To ascertain whether measles vaccination was associated with reduced mortality rates in rural Bangladeshi children, the authors conducted a case-control study in four contiguous areas, two of which had participated in an intensive measles vaccination program which began in the spring of 1982. Cases were 536 children who had died in the four-area region at the age of 10-60 months between April 1982 and December 1984. Two age- and sex-matched controls were selected from the four-area region for each case; each control had survived at least through the date of death of the matched case. Measles vaccination was associated with a 36% (95% confidence interval 21%-48%) proportionate reduction in the overall rate of death and a 57% (95% confidence interval 43%-67%) reduction in the rate of deaths directly attributed to measles or ascribed to diarrhea, respiratory illness, or malnutrition. The association of measles vaccination and reduced mortality remained unchanged after the authors restricted controls to children who had survived at least one year after the deaths of their matched cases. Moreover, children vaccinated in 1982 exhibited a sustained reduction in the rate of death in 1983 and 1984. The authors concluded that measles vaccination was associated with a pronounced and sustained reduction in the rate of death among children in this study.

Initiation of breastfeeding within several hours after a child's birth increases the likelihood of exclusive breastfeeding and longer duration of breastfeeding. However, common beliefs among mothers and health-care providers and routine hospital practices can constrain timely breastfeeding initiation. This article examines the impact of a mass media breastfeeding campaign in Jordan within the context of other activities occurring during and after the child's birth. The campaign had a positive impact on all mothers' knowledge, and on timely initiation of breastfeeding for home and public hospital deliveries, but not for those in private hospitals. The findings indicate that a communication campaign can bring about change in breastfeeding initiation behavior, but that providing mothers with information should be but one part of an integrated program to ensure that hospital and midwife policies and practices support timely initiation.

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