02706nas a2200241   4500008004100000022004800041245007600089210006900165260012800234300000900362490000600371520177000377100002602147700002202173700001802195700002102213700002202234700001602256700002602272700002902298700002702327856011002354       2010                        eng d  a1935-2735 (Electronic); 1935-2727 (Linking)00aLandscape genetics reveals focal transmission of a human macroparasite.0 aLandscape genetics reveals focal transmission of a human macropa  aDepartment of Biology, Texas A&M University, College Station, Texas, United States of America. ccriscione@mail.bio.tamu.edu  ae6650 v43 aMacroparasite infections (e.g., helminths) remain a major human health concern. However, assessing transmission dynamics is problematic because the direct observation of macroparasite dispersal among hosts is not possible. We used a novel landscape genetics approach to examine transmission of the human roundworm Ascaris lumbricoides in a small human population in Jiri, Nepal. Unexpectedly, we found significant genetic structuring of parasites, indicating the presence of multiple transmission foci within a small sampling area ( approximately 14 km(2)). We analyzed several epidemiological variables, and found that transmission is spatially autocorrelated around households and that transmission foci are stable over time despite extensive human movement. These results would not have been obtainable via a traditional epidemiological study based on worm counts alone. Our data refute the assumption that a single host population corresponds to a single parasite transmission unit, an assumption implicit in many classic models of macroparasite transmission. Newer models have shown that the metapopulation-like pattern observed in our data can adversely affect targeted control strategies aimed at community-wide impacts. Furthermore, the observed metapopulation structure and local mating patterns generate an excess of homozygotes that can accelerate the spread of recessive traits such as drug resistance. Our study illustrates how molecular analyses complement traditional epidemiological information in providing a better understanding of parasite transmission. Similar landscape genetic approaches in other macroparasite systems will be warranted if an accurate depiction of the transmission process is to be used to inform effective control strategies.1 aCriscione, Charles, D1 aAnderson, Joel, D1 aSudimack, Dan1 aSubedi, Janardan1 aUpadhayay, Ram, P1 aJha, Bharat1 aWilliams, Kimberly, D1 aWilliams-Blangero, Sarah1 aAnderson, Timothy, J C  uhttps://nematoda.myspecies.info/content/landscape-genetics-reveals-focal-transmission-human-macroparasite