Endamoeba coli

Overview of Endamoeba coli : is defined as infection with the protozoan parasite histolytica . However there are several Endamebas which are closely related to E . histolytica such as E. dipar and E. coli . (Anonymous 1997)

Entamoeba coli are a non-pathogenic species of Entamoeba that frequently exists as a commensal parasite in large intestine of the human . Both cysts and trophozoites of the species are passed in stool and considered diagnostic (CDC 2009). Cysts are typically found in formed stool, whereas trophozoites are typically found in diarrheal stool. Colonization of the nonpathogenic amebae occurs after ingestion of mature cysts in fecally-contaminated food, water, or fomites(CDC 2009).

Summary of data:

Rendtorff, R. C. (1954). "The Experimental Transmission of Human Intestinal Prozoan Parasites.I. Endamoeba coli Cyst Given in Capasules." American Journal of Hygien 59 : 196-208- studied the Entamoeba coli exposure to human volunteers (Rendtorff 1954). Known numbers of cysts of E. coli were administered orally in capsules to volunteers to determine numbers of parasites necessary to establish the infection

Table 1. Summary of data for Entamoeba coli

Experiment Host Type/ Route/ Dose Best Fit Optimized Reference Response ID Number Strain # of Doses Units Model Parameter(s) 50 α = (Rendtorff No. of 0.1008 1 Humans Ingestion – 5 Infection Exponential 341.03 1954) cysts N50 = 341.03

Optimized Models and Fitting Analyses

Optimization Output for experiment 1

Table 2. Humans model data Table 3. Best fitting model determination

Dose Infected Not infected Total 2 Model Deviance ∆∆∆ χχχ 0.95,1 10000 2 0 2 Exponential 27.82 3.8 1000 0 2 2 22.78 Beta Poisson 5.04 100 2 2 4 Beta-Poisson is best fitting model 10 3 7 10

1 1 7 8

(Rendtorff 1954)

Table 4 Optimized parameters for the best fitting (Exponential), obtained from 10,000 bootstrap iterations

Percentiles MLE Parameter Estimate 0.5% 2.5% 5% 95% 97.5% 99.5%

α 0.00108 0.0117 0.0259 0.037 0.2125 0.2597 0.3075

N50 341.03 11.065 18.837 30.496 149244.7 2141374 1.5e7

ID 50 341.03 0.007819 0.093663 0.100392 0.007819 13.25071 67.90096

Figure 1 Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters

Figure 2 Beta-Poisson model plot, with confidence bounds around optimized model

Anonymous (1997). "Entamoeba ." Bulletin of the World Health Organization 75 (3): 291-292.

CDC (2009). Intestinal Amebae. D. o. P. Diseases.

Rendtorff, R. C. (1954). "The Experimental Transmission of Human Intestinal Prozoan Parasites. I. Endamoeba coli Cyst Given in Capasules." American Journal of Hygien 59 : 196-208.