Foodborne Parasites. Foodborne Microbial Pathogens. New York: Springer; 2018. pp. 151-65. [DOI: 10.1007/978-1-4939-7349-1_7]

The Presence of Potentially Pathogenic Protozoa in Lettuce (Lactuca sativa) Sold in Markets in the Central Peruvian Andes

Peru is currently one of the world’s leading culinary destinations, whose world-renowned cuisine uses vegetables, mainly lettuce, as frequent ingredients. Vegetable consumption is promoted worldwide as a part of a healthy diet. However, vegetables, more frequently lettuce, have been implicated as a vehicle of infection for several foodborne parasites. This study aimed to determine the presence of potentially pathogenic parasites in lettuce marketed in the Central Andes of Peru. A total of 75 lettuce samples were collected from the two largest wholesale markets and the main open-air market in Jauja province, in the central Peruvian Andes. The province of provenance (coast vs. highlands), lettuce variety (“curly-leaf”, “iceberg”, and “butter”), and type of market were recorded. The samples were microscopically examined for detection of parasitic life forms using standard parasitological methods including direct slide smear, Lugol’s iodine staining, and Modified Ziehl−Neelsen staining. The overall positivity of parasitic contamination in lettuces was 45.3% (CI 95%: 34−56.6%). Cryptosporidium spp., Isospora belli, Giardia lamblia, Balantidium coli, and Entamoeba spp. were detected in twenty-six (34.7%), six (8%), four (5.3%), two (2.7%), and two (2.7%) lettuces, respectively. I. belli was found in a significantly (p < 0.01) lower proportion in the “butter” variety, and significantly (p < 0.05) higher contamination with G. lamblia was found in lettuce sold at the open-air market. B. coli, G. lamblia, and E. histolytica/E. dispar/E. moshkovskii were detected only in lettuce from the highlands (Tarma province). This study provides important data for health authorities to develop food safety programs. This information is also of interest to the international community because of the increased visibility that Peru has gained as a tourist destination.

Physiology of Electrolyte Transport in the Gut: Implications for Disease

We now have an increased understanding of the genetics, cell biology, and physiology of electrolyte transport processes in the mammalian intestine, due to the availability of sophisticated methodologies ranging from genome wide association studies to CRISPR-CAS technology, stem cell-derived organoids, 3D microscopy, electron cryomicroscopy, single cell RNA sequencing, transgenic methodologies, and tools to manipulate cellular processes at a molecular level. This knowledge has simultaneously underscored the complexity of biological systems and the interdependence of multiple regulatory systems. In addition to the plethora of mammalian neurohumoral factors and their cross talk, advances in pyrosequencing and metagenomic analyses have highlighted the relevance of the microbiome to intestinal regulation. This article provides an overview of our current understanding of electrolyte transport processes in the small and large intestine, their regulation in health and how dysregulation at multiple levels can result in disease. Intestinal electrolyte transport is a balance of ion secretory and ion absorptive processes, all exquisitely dependent on the basolateral Na⁺ /K⁺ ATPase; when this balance goes awry, it can result in diarrhea or in constipation. The key transporters involved in secretion are the apical membrane Cl^- channels and the basolateral Na⁺ -K⁺ -2Cl^- cotransporter, NKCC1 and K⁺ channels. Absorption chiefly involves apical membrane Na⁺ /H⁺ exchangers and Cl^- /HCO₃ ^- exchangers in the small intestine and proximal colon and Na⁺ channels in the distal colon. Key examples of our current understanding of infectious, inflammatory, and genetic diarrheal diseases and of constipation are provided. © 2019 American Physiological Society. Compr Physiol 9:947-1023, 2019.