Toxoplasmagondii oocysts, Giardia cysts and Cryptosporidium oocysts in outdoor swimming pools in Brazil

Abstract

The accidental ingestion of treated recreational water is an important transmission route of waterborne protozoa worldwide. The present study aimed to provide the first evaluation of swimming pools in Brazil, analysing the presence of pathogenic protozoa (Toxoplasma gondii, Cryptosporidium spp. and Giardia spp.) by parasitological and molecular methods. A total of 57 samples were collected from 21 public swimming pools, either directly from the pool or filter backwash water and concentrated using the membrane filtration technique. Giardia cysts and Cryptosporidium oocysts were visualized by direct immunofluorescence assay after purification by immunomagnetic separation. Toxoplasma gondii oocysts were detected by autofluorescence visualization using the supernatant discarded during the purification step as a sample. Positive samples were submitted to molecular analysis. The molecular markers were used: SSU-rRNA, tpi, gdh and bg, for Giardia DNA amplification, and 18S rRNA gene fragment amplification was used for the Cryptosporidium oocysts. The 529-bp repeat element (REP529) fragment and the 35-fold repetitive B1 gene were employed as a target for T. gondii. Amplified products were submitted to sequencing and phylogenetic analysis. Giardia cysts were detected in 19.0% and Cryptosporidium oocysts in 9.5% of swimming pools. In one swimming pool (4.7%), both protozoa were detected on at least one occasion. Structures similar to T. gondii oocysts were detected in 33.3% of the samples, ranging from one to 23 per slide. Giardia was confirmed by DNA amplification in three swimming pools; Giardia duodenalis Assemblage A was identified by the phylogenetic positioning of the β-giardin gene. Toxoplasma gondii DNA was detected in 14.2% of swimming pools. The present study represents the first report of the occurrence of T. gondii oocysts in swimming pools. Recreational activity in swimming pools contaminated by chlorine-resistant protozoa can represent a high risk of infection for bathers and swimmers.

Epidemiology of Giardia duodenalis assemblages in Brazil: there is still a long way to go

“…(33) Six studies that used the SSU-rRNA marker in a multiplex approach with bg, gdh or tpi (Table I). (32,40,41,59,60,61) The low investment in tools with discriminatory potential results that sequencing is still the most widely used methodology, although it may present divergences according to the gene target used. The whole genome sequencing (WGS) is suggested for genotyping; (10) however, the high cost and the delay in obtaining results prevent its use on a large scale, especially in developing countries, such as Brazil.…”

“…In Brazil, genotyping studies of G. duodenalis in water are basically concentrated in the State of São Paulo, (42,44,45,57,58,59,61) and in the State of Paraná, which pres- (72,76) B (72,76) Ceará Human A (68,76) B (68,76) Piauí Human A (76) B (76) Bahia Human A (21) B (21) Minas Gerais Human A (46,74) B (70,74) E (74) Dog A (46,84) B (84) C ( 84) D ( 84) E (84) Cattle A (86) B (86) E (86) Pig E (86) Sheep B (86) E (86) Toco toucan A (33) Rio de Janeiro Human A (8,28,43,75) B (43,75) E (8)…”

“…A (28,83) Cat A (28) São Paulo Human A (42,67,69,71,73,78) B (42,67,71,73,78) C (42) Dog A (42,69,71) B (42) C (42,47,67,71) D (42,47,67,71) Cat A (42,67) B (42) D (42) F (67) Buffalo E (60) Cattle A (40,42,67) E (40,42,67) Sheep E (50) Nonhuman primates A (85) Oyster A (58) Water and/or Sewage A (44,45,57,58,59,61) B (57,59,42,44) C…”

Dairy wastewater treatment employing microencapsulated Pseudomonas aeruginosa on low acyl gellan gum

“…In Brazil, the membrane filtration technique is the most used alternative for the research analysis of Giardia spp. cysts in various water matrices (Rosado-García et al, 2017), being detected in raw and treated water from rivers (Scherer et al, 2022;Bonatti et al, 2023), treated sewage (Miglioli et al, 2017), marine and estuarine waters (Leal et al, 2018), and swimming pools (Pineda et al, 2020). However, this technique also presents limitations when used in highturbidity water samples (Coelho et al, 2017).…”