Blastocystis genetic diversity among children of low-income daycare center in Southeastern Brazil

Abstract

Blastocystis, an unicellular anaerobic eukaryote, is known to be a very common intestinal parasite found in humans and animals fecal samples worldwide. Currently, there is an increasing interest to yield insights into its prevalence and diversity in human populations living in poor and deprived areas. In this study, we describe the prevalence and genetic variability of Blastocystis isolates obtained from daycare center attendees aged 0 to 6years and staff, as well as some children family members and their dogs in a low-income community in São Paulo State, Brazil. A total of 181 stool samples (123 from daycare children, 14 from workers, 44 from household members and 20 from dogs) were submitted to DNA extraction, tested by polymerase chain reaction (PCR) targeting the SSUrDNA gene and the amplicons retrieved were sequenced. The prevalence of Blastocystis was 40.7% (50/123) in children, 28.6% (4/14) in workers and 50% (22/44) in household members. No dog was found positive. Of the 76 PCR products generated, 57 were successfully sequenced. Four subtypes were identified and the most common were ST1 (54.4%) and ST3 (33.3%), followed by ST2 (7.0%) and ST7 (5.3%). The intra-subtype analysis revealed a total of 10 different alleles previously reported. No statistically significant correlation was observed between subtypes and sociodemographic variables analyzed. Here, the following findings must be highlighted: (1) predominance of subtypes 1 and 3, a pattern that has been observed in many populations worldwide; (2) absence of ST4, a common subtype in Europe but rarely detected in South America's human populations and, (3) human infection with ST7, a subtype primarily found in birds but occasionally seen in human infections, raising the possibility of zoonotic transmission.

Genetic Diversity and Distribution ofBlastocystisSubtype 3 in Human Populations, with Special Reference to a Rural Population in Central Mexico

“…In some studies, it has been observed that this subtype has been strongly related to rural populations [ 8 , 43 ]. It is possible to hypothesize that the migration phenomenon [ 42 ] occurs mainly from the displacement of these rural communities infected with Blastocystis ST3 haplotype 1 spreading this parasite into the cities.…”

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 Study on the Prevalence and Subtype Diversity of the Intestinal Protist Blastocystis sp. in a Gut-Healthy Human Population in the Czech Republic

“…In developing countries, Blastocystis sp. is, with prevalence up to 100%, a practically obligate finding in some populations (El Safadi et al, 2014 ; Poulsen et al, 2016 ; Mohammad et al, 2017 ; Oliveira-Arbex et al, 2018 ), whereas the prevalence reported in industrialized countries most commonly ranges between 7 and 50% (Bart et al, 2013 ; Scanlan et al, 2014 , 2016 ; El Safadi et al, 2016 ; Seyer et al, 2017 ). While the frequent occurrence of Blastocystis sp.…”