Multilocus Genotyping of Human Giardia Isolates Suggests Limited Zoonotic Transmission and Association between Assemblage B and Flatulence in Children

Giardia intestinalis is a protozoan parasite found world-wide and it is a major cause of diarrhea in humans and other mammals. The genetic variability within G. intestinalis is high with eight distinct genotypes or assemblages (A-H). Here we performed sequence-based multilocus genotyping of around 200 human Giardia isolates. We found evidence of limited zoonotic transmission of certain A subtypes and an association between flatulence and assemblage B infection in children. This shows that it is important to investigate different assemblages and sub-assemblages of G. intestinalis in human infections in order to understand the clinical significance, zoonotic potential, sequence divergence, and transmission pathways of this parasite

Ecological determinants of pathogen infection in howler monkeys

Infectious diseases caused by pathogens are now recognized as one of the most important threats to primate conservation. The fact that howler monkeys (Alouatta spp.) are widely distributed from Southern Mexico to Northern Argentina, inhabit a diverse array of habitats, and are considered pioneers, particularly adapted to exploit marginal habitats, provides an opportunity to explore general trends of parasitism and evaluate the dynamics of infectious diseases in this genus. We take a meta-analysis approach to examine the effect of ecological and environmental variables on parasitic infection using data from 7 howler monkey species at more than 35 sites throughout their distribution. We found that different factors including precipitation, latitude, altitude, and human proximity may infl uence parasite infection depending on the parasite type. We also found that parasites infecting howler monkeys followed a right-skewed distribution, suggesting that only a few individuals harbor infections. This result highlights the importance of collecting large sample sizes when developing these kinds of studies. We suggest that future studies should focus on obtaining fi ne-grained measurements of ecological and microclimate changes to provide better insights into the proximate factors that promote parasitism.Fil: Martinez Mota, Rodolfo. University of Illinois at Urbana-Champaign; Estados UnidosFil: Kowalewski, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Biológica de Usos Múltiples (Sede Corrientes); ArgentinaFil: Gillespie, Thomas R.. Emory University; Estados Unido