caa a22 4500 386399832 CHVBK 20180307112154.0 cr unu---uuuuu 161130e198910 xx s 000 0 eng 10.1017/S0031182000058753 doi S0031182000058753 pii (NATIONALLICENCE)cambridge-10.1017/S0031182000058753 The weight/length profiles of Ascaris lumbricoides within a human community before mass treatment and following reinfection [Elektronische Daten] Weight and length profiles are presented of 3505 Ascaris worms recovered after mass anthelmintic treatment of a human community in January 1984 and, after an 11 month period of reinfection, in November 1984. Male and female worms recovered after reinfection were significantly heavier and longer than those expelled after initial treatment (P < 0·0001). Multiple regression models were employed to examine variability in parasite size. A positive influence of host body weight on the weight of parasites recovered in January, but not in November, was observed. No negative relationship was recorded at either date between worm size and the total number of worms harboured, even after controlling for host weight. Striking host age-related variability was observed in the distribution profile of weights and lengths of individual worms recovered in January. Children harboured predominantly smaller worms before initial treatment, while adults expelled mainly heavy worms. In contrast, worms expelled by both children and adults after reinfection were heavier and more homogeneous in size, particularly within the relatively heavily infected group. These patterns argue against a primary role for density- dependent or acquired resistance mechanisms in determining the size of Ascaris in humans. However, the results are consistent with a hypothesis initially suggested by Jung (1954) that established worms may inhibit the development of newly acquired Ascaris larvae, perhaps regulating their own abundance. Copyright © Cambridge University Press 1989 Ascaris lumbricoides nationallicence weight profiles nationallicence length profiles nationallicence anthelmintic treatment nationallicence Elkins D. B. Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, London SW7 2BB Haswell-Elkins M. Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, London SW7 2BB Parasitology Cambridge University Press 99/2(1989-10), 293-299 0031-1820 99:2<293 1989 99 PAR https://doi.org/10.1017/S0031182000058753 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0031182000058753 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Elkins D. B. Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, London SW7 2BB NATIONALLICENCE 700 1- Haswell-Elkins M. Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, London SW7 2BB NATIONALLICENCE 773 0- Parasitology Cambridge University Press 99/2(1989-10), 293-299 0031-1820 99:2<293 1989 99 PAR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge