A household-based study of contact networks relevant for the spread of infectious diseases in the highlands of Peru.
BACKGROUND
Few studies have quantified social mixing in remote rural areas of developing countries, where the burden of infectious diseases is usually the highest. Understanding social mixing patterns in those settings is crucial to inform the implementation of strategies for disease prevention and control. We characterized contact and social mixing patterns in rural communities of the Peruvian highlands.


RESULTS
This cross-sectional study was nested in a large prospective household-based study of respiratory infections conducted in the province of San Marcos, Cajamarca-Peru. Members of study households were interviewed using a structured questionnaire of social contacts (conversation or physical interaction) experienced during the last 24 hours. We identified 9015 reported contacts from 588 study household members. The median age of respondents was 17 years (interquartile range [IQR] 4-34 years). The median number of reported contacts was 12 (IQR 8-20) whereas the median number of physical (i.e. skin-to-skin) contacts was 8.5 (IQR 5-14). Study participants had contacts mostly with people of similar age, and with their offspring or parents. The number of reported contacts was mainly determined by the participants' age, household size and occupation. School-aged children had more contacts than other age groups. Within-household reciprocity of contacts reporting declined with household size (range 70%-100%). Ninety percent of household contact networks were complete, and furthermore, household members' contacts with non-household members showed significant overlap (range 33%-86%), indicating a high degree of contact clustering. A two-level mixing epidemic model was simulated to compare within-household mixing based on observed contact networks and within-household random mixing. No differences in the size or duration of the simulated epidemics were revealed.


CONCLUSIONS
This study of rural low-density communities in the highlands of Peru suggests contact patterns are highly assortative. Study findings support the use of within-household homogenous mixing assumptions for epidemic modeling in this setting.
Department of Health Policy, Vanderbilt University School of Medicine, Nashville, TN, United States of America.
Carlos G
CG
Grijalva
Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium; Centre for Health Economics Research and Modeling Infectious Diseases, and Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium.
Nele
N
Goeyvaerts
Instituto de Investigación Nutricional, Lima, Peru.
Hector
H
Verastegui
Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, United States of America.
Kathryn M
KM
Edwards
Instituto de Investigación Nutricional, Lima, Peru.
Ana I
AI
Gil
Instituto de Investigación Nutricional, Lima, Peru.
Claudio F
CF
Lanata
Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Diepenbeek, Belgium; Centre for Health Economics Research and Modeling Infectious Diseases, and Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium.
Niel
N
Hens
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003147:Communication Disorders / Q000453:epidemiology* / Q000517:prevention & control; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010568:Peru; D011446:Prospective Studies; D012424:Rural Population; D060756:Social Networking; D011795:Surveys and Questionnaires