Intestinal symptoms and Blastocystis load in schoolchildren of Paranaguá Bay, Paraná, Brazil

Abstract

The symptomatology of Blastocystis cannot be attributed to any particular subtype, although can be related to a high Blastocystis infection load. One stool sample from each of 217 schoolchildren of Vale de Sol Paranaguá Bay (Paraná, Brazil) was collected. Three milliliters of each fixed stool sample were processed applying the formalin-ether concentration technique. After obtaining the overall prevalence of intestinal parasites, quantification was carried out in Blastocystis positive samples. A total of 75/217 (34.6%) children suffered from intestinal symptoms (abdominal pain and/or persistent diarrhea), of whom 41.3% (31/75) presented moderate/heavy Blastocystis load with a statistically significant risk to present intestinal symptoms (OR 0.039 [0.006-0.15]; p<0.001) Moreover, those symptomatic schoolchildren monoparasitized only by Blastocystis (10/75, 13.3%), and those polyparasitized by Blastocystis with other non-pathogenic species (15/75, 20%) with moderate/heavy loads, also entail a statistically significant risk of intestinal symptomatology, both in monoparasitism (12%, OR 0.10 [0.004-0.63]; p=0.021) and in polyparasitism with a non-pathogenic parasite (18.6%, OR 0.059 [0.002-0.35]; p=0.001). For the first time in Brazil, using data from schoolchildren of Paranaguá Bay, we demonstrated that moderate/ heavy loads of Blastocystis could be related to intestinal symptoms.

A summary of Blastocystis subtypes in North and South America

“…3a shows the ST1-positive samples obtained from humans, which are represented by green points. This ST was identified in studies from Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, USA and Mexico [2, 9, 11, 13, 21–25, 27, 29–35, 37–39, 42, 43, 46–50]. In addition, positive samples for ST2 shown in panel b of the map in Fig.…”

“…Among the studies conducted in North and South America, the most widespread subtypes we collated were ST1 and ST2, which were present in the samples from eight of the nine countries that were studied [2, 9–11, 17, 21–27, 29–39, 42, 43, 45–50]. Subsequently, ST3 was found in seven of the nine countries [2, 9–11, 13, 17, 21, 23–25, 27, 30, 31, 33–37, 39, 42, 43, 46–50].…”

“…In addition, positive samples for ST2 shown in panel b of the map in Fig. 3 (represented by yellow points) are limited to Argentina [13], Brazil [9, 11, 21, 22, 24, 27, 29–31], Bolivia [9, 32, 33], Colombia [2, 9, 35, 37], Ecuador [39], Chile [38], USA [38, 46] and México [49, 50]. The ST3 positive samples, represented in Fig.…”

Prevalence of Blastocystis sp. infection in several hosts in Brazil: a systematic review and meta-analysis

“…Oliveira-Arbex et al [45] Melo et al [49] David et al [9] Branco et al [58] Miné et al [66] Alarcón et al [68] Kobayashi et al [76] Seguí et al [50] Takizawa et al [64] Borges et al [63] Kulik et al [65] Subtotal (I^2 = 95.61%, p = 0.00) Subtotal (I^2 = 99.28%, p = 0.00)…”

A Simple Genotyping Method for Rapid Differentiation of Blastocystis Subtypes and Subtype Distribution of Blastocystis spp. in Thailand

“…The public health significance of Blastocystis infection has increased in the last decade. Blastocystis infection causes various symptoms in immunocompetent individuals in the absence of any parasitic co-infection [2,3]. Prevalence of Blastocystis infection is about 1%–23% in developed countries [4,5], and 10%–100% in developing countries [6,7,8].…”