Symptomatic and Asymptomatic Protist Infections in Hospital Inpatients in Southwestern China.

Shun-Xian Zhang,Ying-Fang Yu,David Carmena,Chun-Li Yang,Yan-Hong Chu,Xiu-Ping Wu,Li-Guang Tian,Cristina Ballesteros,Emmanuel Serrano,Jia-Xu Chen

doi:10.3390/pathogens10060684

Abstract

Cryptosporidium spp., Entamoeba histolytica, Giardia duodenalis, and Blastocystis sp. infections have been frequently reported as etiological agents for gastroenteritis, but also as common gut inhabitants in apparently healthy individuals. Between July 2016 and March 2017, stool samples (n = 507) were collected from randomly selected individuals (male/female ratio: 1.1, age range: 38–63 years) from two sentinel hospitals in Tengchong City Yunnan Province, China. Molecular (PCR and Sanger sequencing) methods were used to detect and genotype the investigated protist species. Carriage/infection rates were: Blastocystis sp. 9.5% (95% CI: 7.1–12.4%), G. duodenalis 2.2% (95% CI: 1.1–3.8%); and E. histolytica 2.0% (95% CI: 0.9–3.6%). Cryptosporidium spp. was not detected at all. Overall, 12.4% (95% CI: 9.7–15.6) of the participants harbored at least one enteric protist species. The most common coinfection was E. histolytica and Blastocystis sp. (1.0%; 95% CI: 0.3–2.2). Sequence analyses revealed that 90.9% (10/11) of the genotyped G. duodenalis isolates corresponded to the sub-assemblage AI. The remaining sequence (9.1%, 1/11) was identified as sub-assemblage BIV. Five different Blastocystis subtypes, including ST3 (43.7%, 21/48), ST1 (27.1%, 13/48), ST7 (18.8%, 9/48), ST4 (8.3%, 4/48), and ST2 (2.1%, 1/48) were identified. Statistical analyses confirmed that (i) the co-occurrence of protist infections was purely random, (ii) no associations were observed among the four protist species found, and (iii) neither their presence, individually or jointly, nor the patient’s age was predictors for developing clinical symptoms associated with these infections. Overall, these protist mono- or coinfections are asymptomatic and do not follow any pattern.

Highlights

Parasitic infections have been frequently reported as significant causes of gastrointestinal disorders and major contributors to the global burden of diarrheal disease globally [1,2,3,4,5].Several diarrhea-causing enteric parasite species have been described in humans
It is estimated that around 20% of child diarrheal episodes are reported in low and middle-income countries, and 9% of those documented in high-income settings are caused by Cryptosporidium spp
Blastocystis sp. was the most prevalent protist species found (9.5%, 48/507; 95% confidence intervals (95% CIs): 7.1–12.4), followed by G. duodenalis (2.2%, 11/507; 95% CI: 1.1–3.8) and E. histolytica (2.0%, 10/507; 95% CI: 0.9–3.6), whereas Cryptosporidium spp. was not detected at all

Summary

Introduction

Parasitic infections have been frequently reported as significant causes of gastrointestinal disorders and major contributors to the global burden of diarrheal disease globally [1,2,3,4,5].Several diarrhea-causing enteric parasite species have been described in humans. Parasitic infections have been frequently reported as significant causes of gastrointestinal disorders and major contributors to the global burden of diarrheal disease globally [1,2,3,4,5]. The acute disease caused by E. histolytica, affects near 50 million people and causes 100,000 deaths each year [7]. Both Cryptosporidium spp. and E. histolytica have been recognized as significant causes of morbidity and mortality associated with diarrhea by the 2017 Global Burden Disease Study [4]. Besides Blastocystis sp., Cryptosporidium spp., E. histolytica, and G. duodenalis infections are common in apparently healthy individuals [1,14,15]. There is a lack of reliable data on the true burden of asymptomatic infections due to the absence of monitoring programs, underreporting and the fact that carriage of subclinical stages is often underdiagnosed [1,16,17]

Methods

Discussion

Conclusion