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Levy, M. Z.

Publications and source records attributed to Levy, M. Z..

2 recordsLinked to original sources

Socio-spatial heterogeneity in participation in mass dog vaccination campaigns, Arequipa, Peru

To control and prevent rabies in Latin America, mass dog vaccination campaigns (MDVC) are implemented mainly through fixed-location vaccination points: owners have to bring their dogs to the vaccination points where they receive the vaccination free of charge. Dog rabies is still endemic in some Latin-American countries and high overall dog vaccination coverage and coverage evenness are desired attributes of MDVC to halt rabies virus transmission. In Arequipa, Peru, we conducted a door-to-door post-campaign survey on >6,000 houses to assess the placement of vaccination points on these two attributes. We found that the odds of participating in the campaign decreased by 16% for every 100 m from the owners house to the nearest vaccination point (p=0.041) after controlling for potential covariates. We found social determinants associated with participating in the MDVC: for each child under 5 in the household the odds of participating in the MDVC decreased by 13% (p=0.032), and for every ten more years living in the area, the odds of participating in the MDVC increased by 9% (p<0.001), after controlling for distance and other covariates. We also found significant spatial clustering of unvaccinated dogs over 500m from the vaccination points, which created pockets of unvaccinated dogs that may sustain rabies virus transmission. Understanding the barriers to dog owners participation in community-based dog-vaccination programs will be crucial to implement effective zoonotic disease preventive activities. Spatial and social elements of urbanization play an important role in coverage of MDVCs and should be considered during their planning and evaluation.

epidemiology

Immigration and establishment of urban Trypanosoma cruzi populations

Changing environmental conditions, including those caused by human activities, reshape biological communities through both loss of native species and establishment of non-native species in the altered habitats. Dynamic interactions with the abiotic environment impact both immigration and initial establishment of non-native species into these altered habitats. The repeated emergence of disease systems in urban areas worldwide highlights the importance of understanding how dynamic migratory processes affect the current and future distribution and abundance of pathogens in urban environments. In this study, we examine the pattern of invasion of Trypanosoma cruzi--the causative agent of human Chagas disease--in the city of Arequipa, Peru. Phylogenetic analyses of 136 T. cruzi isolates from Arequipa and other South American locations suggest that only one T. cruzi immigrant established a population in Arequipa as all T. cruzi isolated from vectors in Arequipa form a recent monophyletic group within the broader South American phylogeny. We discuss several hypotheses that may explain the limited number of established T. cruzi lineages despite multiple introductions of the parasite.\n\nAuthor SummaryHuman-associated pests and pathogens, who benefit from the abundance of humans and human-associated hosts or vectors, commonly invade environments altered by human activities. As the number and size of human-disturbed environments increase, so does the importance of identifying ecological and environmental factors that affect the probability that disease systems immigrate to, subsequently establish populations in, urban environments. We examined the number and timing of immigration and establishment events of Trypanosoma cruzi, the causative agent of Chagas disease, in a currently endemic area. Phylogenetic analyses of 136 T. cruzi isolates suggests that the current population descended from a single, recent immigration event. We discuss historical and ecological hypotheses that can explain the limited T. cruzi diversity in this region.

evolutionary biology