An Overview of Mucosa-Associated Protozoa: Challenges in Chemotherapy and Future Perspectives

Childhood Intestinal Parasitic Reinfection, Sanitation and Hygiene Practice in Eastern Ethiopia: Case Control Study

Background

The recurrence of intestinal parasitic infections (IPIs) can lead to different problems that can be transferred from generation to generation. Sanitation and hygienic practices have vital role in the parasitic reinfection. In poor hygienic and sanitation condition children may live in a continuous cycle of infection and reinfection.

Objective

To assess childhood IP reinfection and its association with sanitation and hygienic practice in eastern Ethiopia.

Methods

A population-based case-control design was used in this study. Data were collected from 75 reinfected cases and 147 unmatched controls. Fecal specimens were observed for parasites using direct smear and formol ether techniques. Epi-Info and SPSS (the statistical package for social science) were used for data entry and analysis, respectively. Logistic regression analysis was conducted to identify significant associations (P<0.05) between variables.

Results

The overall IP reinfection rate within 24 weeks after treatment was 33.8% (75/222), with a 95% CI=27.7%-40.5%. The frequency of intestinal protozoa was 18%, and for helminths was 15.8%. Children who swam in a polluted water had 3.7 times greater odds of IP reinfection than children who did not swim (P =0.01, 95% CI: 1.4-10.0). Children who regularly bathed in streams and children who bathed both at home and in streams were found to have 12.6 times and 5.8 times higher odds of IP reinfection than children who bathed regularly at home (P=0.002, 95% CI:2.5-64.8) and (P = 0.042, 95% CI:1.1-31.3), respectively. Children in households that owned domestic animals had 4.5 times higher odds of IP reinfection than the reference group (P = 0.013, 95% CI: 1.3-12.5).

Conclusion

IP reinfection rates were significantly associated with habits of swimming in a polluted water, places of bathing, and ownership of domestic animals. Therefore, efforts should be made considering such factors to minimize IP reinfection in the area.

Giardia lamblia Diagnosed During Upper Gastrointestinal Endoscopy: Clinical Manifestation, Histopathologic Findings and the Association With Celiac Disease

BACKGROUND

Giardia lamblia may be found incidentally during upper gastrointestinal (GI) endoscopy, including when biopsies are taken for celiac disease (CeD) diagnosis. We aimed to study the clinical presentation and histopathology of G. lamblia and determine its association with CeD.

METHODS

A retrospective case series of pediatric patients diagnosed with G. lamblia based on intestinal biopsies between January 1999 and January 2023. Baseline data; demographics, symptoms, celiac serology, stool testing, macroscopic and histopathologic findings. Follow-up data; treatment and repeated celiac serology.

RESULTS

Of 38 patients with G. lamblia , 15 (39.5%) were female, mean age of 6.7 (±4.8 SD) years. Clinical symptoms; GI 19/38 (50%), growth retardation and/or iron deficiency anemia 8/38 (21.1%) or a combination 11/38 (28.9%). Celiac serology was positive in 13/38 (34.2%). Duodenal endoscopic findings; normal (n = 23, 60.5%), nodularity (n = 12, 32.4%), erosions in 2 (5.4%) and scalloping in 1 (2.7%). Histopathology; normal villi 24/38 (63.2%), villous shortening with increased intraepithelial lymphocytes (IEL) 5/38 (13.2%), isolated IEL 3/38 (7.9%) and duodenitis in 6/38 (15.8%). Children with positive CeD serology were younger (4 vs. 8.1 years, P = 0.019), had fewer GI symptoms (23.1% vs. 64%, P = 0.017) and a higher rate of villous shortening with increased IEL (38.5% vs. 0, P < 0.001) versus children with negative serology. On follow-up, metronidazole treatment was recommended to all but was documented to be given in 22/38 (57.9%). Among the 13 children with positive CeD serology, serology normalized in 10 (77%).

CONCLUSIONS

G. lamblia is a rare histopathologic finding in children. It may be an incidental finding in CeD or may cause false positive celiac serology.

Anaerobic energy metabolism in human microaerophile parasites

Mucosal-associated parasites, such as Giardia intestinalis, Entamoeba histolytica, and Trichomonas vaginalis, have significant clinical relevance. The pathologies associated with infection by these parasites are among those with the highest incidence of gastroenteritis (giardiasis and amoebiasis) and sexually transmitted infections (trichomoniasis). The treatment of these diseases is based on drugs that act on the anaerobic metabolism of these parasites, such as nitroimidazole and benzimidazole derivatives. One interesting feature of parasites is their ability to produce ATP under anaerobic conditions. Due to the absence of enzymes capable of producing ATP under anaerobic conditions in the vertebrate host, they have become interesting therapeutic targets. This review discusses anaerobic energy metabolism in mucosal-associated parasites, focusing on the anaerobic metabolism of pyruvate, the importance of these enzymes as therapeutic targets, and the importance of treating their infections.

Protozoa-Derived Extracellular Vesicles on Intercellular Communication with Special Emphasis on Giardia lamblia

Parasitic diseases are an important worldwide problem threatening human health and affect millions of people. Acute diarrhea, intestinal bleeding, malabsorption of nutrients and nutritional deficiency are some of the issues related to intestinal parasitic infections. Parasites are experts in subvert the host immune system through different kinds of mechanisms. There are evidences that extracellular vesicles (EVs) have an important role in dissemination of the disease and in modulating the host immune system. Released by almost all types of cells, these nanovesicles are a natural secretory product containing multiple components of interest. The EVs are classified as apoptotic bodies, microvesicles, exosomes, ectosomes, and microparticles, according to their physical characteristics, biochemical composition and cell of origin. Interestingly, EVs play an important role in intercellular communication between parasites as well as with the host cells. Concerning Giardia lamblia, it is known that this parasite release EVs during it life cycle that modulate the parasite growth and adherence as well the immune system of the host. Here we review the recently updates on protozoa EVs, with particular emphasis on the role of EVs released by the flagellate protozoa G. lamblia in cellular communication and its potential for future applications as vaccine, therapeutic agent, drug delivery system and as diagnostic or prognostic biomarker.

Unusual Cell Structures and Organelles in Giardia intestinalis and Trichomonas vaginalis Are Potential Drug Targets

This review presents the main cell organelles and structures of two important protist parasites, Giardia intestinalis, and Trichomonas vaginalis; many are unusual and are not found in other eukaryotic cells, thus could be good candidates for new drug targets aimed at improvement of the chemotherapy of diseases caused by these eukaryotic protists. For example, in Giardia, the ventral disc is a specific structure to this parasite and is fundamental for the adhesion and pathogenicity to the host. In Trichomonas, the hydrogenosome, a double membrane-bounded organelle that produces ATP, also can be a good target. Other structures include mitosomes, ribosomes, and proteasomes. Metronidazole is the most frequent compound used to kill many anaerobic organisms, including Giardia and Trichomonas. It enters the cell by passive diffusion and needs to find a highly reductive environment to be reduced to the nitro radicals to be active. However, it provokes several side effects, and some strains present metronidazole resistance. Therefore, to improve the quality of the chemotherapy against parasitic protozoa is important to invest in the development of highly specific compounds that interfere with key steps of essential metabolic pathways or in the functional macromolecular complexes which are most often associated with cell structures and organelles.