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The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban communities in the state of Piauí, Brazil. Our cross-sectional survey included 100 fecal samples obtained from swine and 682 samples from humans. Fifteen pigs were necropsied. Human and porcine fecal samples were examined to identify Ascaris eggs. Parasites obtained in the swine necropsies were studied using scanning electron microscopy (SEM), and the mitochondrial gene encoding the cytochrome oxidase 1 (cox1) enzyme was partially amplified and sequenced for molecular taxonomy and phylogenetic analyses. The overall prevalence of Ascaris eggs in the swine fecal samples was 16/100 (16%). No Ascaris eggs were identified in the human fecal samples. SEM of six worms recovered from pigs demonstrated morphological characteristics of A. suum. Cox1 sequences were compatible with A. suum reference sequences. Original and reference (GenBank) nucleotide sequences were organized into clusters that did not segregate the parasites by host species or and region. The largest haplogroups were dominated by haplotypes H01, H02 and H31. In the communities studied, there was no epidemiological evidence of the zoonotic transmission of ascariasis at the human-swine interface.

Metastrongylosis is an infection of the respiratory tract of pigs caused by parasites of the genus Metastrongylus , whose eggs are similar to other Strongylida through light microscopy; species-specific identification can be performed with molecular tools. We explored the species composition and the genetic diversity of Metastrongylus infecting pigs in close contact with humans in impoverished rural communities in the state of Piauí, in northeastern Brazil. Fecal samples ( n  = 78) were collected for parasitologic tests. Egg morphometry and molecular characterization, using the cytochrome c oxidase subunit 1 ( cox 1) gene, were performed. For strongyliform eggs, 62 of 78 (80%) pigs were positive and 6 of 99 (6%) eggs had dimensions compatible with Metastrongylus . Of the 37 samples submitted to PCR, 10 were identified as M. salmi . We found 3 M. salmi haplotypes, including 2 new and 1 described previously in Europe. Overall, M. salmi demonstrated lower intraspecific genetic diversity: diversity index (H) ± SD = 0.318 ± 0.164, n  = 12, compared with published M. pudendotectus sequences (1.000 ± 0.272, n  = 3). To our knowledge, M. salmi DNA sequences have not been published previously from pigs in South America.

Human infections with gut protozoan parasites are neglected and not targeted by specific control initiatives, leading to a knowledge gap concerning their regional diversity and epidemiology. The present study aims to explore Giardia duodenalis genetic diversity and assess the epidemiologic scenario of subclinical infections in different Brazilian biogeographic regions. Cross-sectional surveys (n = 1334 subjects) were conducted in four municipalities in order to obtain fecal samples and socioenvironmental data. Microscopy of non-diarrheal feces and nucleotide sequencing of a β-giardin gene fragment were performed. From a total of 51 samples that could be sequenced, 27 (52.9%) β-giardin sequences were characterized as assemblage A and 24 (47.1%) as assemblage B. In the Amazon, assemblage B was the most frequently detected, predominantly BIII, and with two novel sub-assemblages. Assemblage A predominated in the extra-Amazon region, with five novel sub-assemblages. Prevalence reached 17.8% (64/360) in the Amazon, 8.8% (48/544) in the Atlantic Forest, 7.4% (22/299) in Cerrado and 2.3% (3/131) in the Semiarid. People living in poverty and extreme poverty presented significantly higher positivity rates. In conclusion, subclinical giardiasis is endemic in Brazilian communities in different biogeographic regions, presenting high genetic diversity and a heterogeneous genotypic distribution.

Helminths of the genus Oesophagostomum cause enteric diseases and affect domestic animals such as pigs. The aim of this study was to explore the species composition and genetic diversity of Oesophagostomum spp. infecting pigs in close contact with humans in the state of Piauí, Brazil. Eighty-seven fecal samples were collected for parasitological tests and molecular analysis. Through microscopy, the overall positivity rate for strongyliform eggs was 81.6% among the pigs studied. Forty-two strongyliform egg samples were subjected to PCR and six cox1 sequences (637 bp) were identified for the genus Oesophagostomum. The sequences were identified as Oesophagostomum dentatum, O. quadrispinulatum and O. columbianum. In the phylogenetic tree and haplotype network, 89 sequences were separated into seven clusters, which also included reference sequences from GenBank. Oesophagostomum dentatum and O. quadrispinulatum were seen to be closely related species and formed a monophyletic group related to O. aculeatum. Oesophagostomum columbianum showed similarity with sequences from parasites infecting small ruminants and the clade was positioned closer to O. bifurcum. High interspecific diversity was found and intraspecific diversity varied according to the species. This was the first study to characterize Oesophagostomum DNA sequences obtained from pigs in Brazil.

Background: This study assessed the interactions between income, nutritional status and intestinal parasitism in children in Brazil., Methods: A cross-sectional study (n = 421 children aged 1 to 14 years living in the states of Piauí (rural communities in the city of Teresina) and Rio de Janeiro (rural and periurban communities in the city of Cachoeiras de Macacu) was performed in order to obtain income and anthropometric data, as well as fecal samples for parasitological analyses through the Ritchie technique., Results: Children infected with Ascaris lumbricoides had significantly lower means of height-for-age z scores (- 1.36 ± 0.75 vs. - 0.11 ± 1.02; p < 0.001), weight-for-age z scores (- 1.23 ± 0.74 vs. 0.09 ± 1.15; p = 0.001), and weight-for-height z scores (- 0.68 ± 0.44 vs. 0.23 ± 1.25; p = 0.006) when compared with uninfected children. Infection with hookworm was also associated with lower means of height-for-age z scores (- 1.08 ± 1.17 vs. - 0.12 ± 1.02; p = 0.015) and weight-for-age z scores (- 1.03 ± 1.13 vs. 0.08 ± 1.15; p = 0.012). Children infected with Entamoeba coli presented significantly lower means of height-for-age z scores (- 0.54 ± 1.02 vs. - 0.09 ± 1.02; p = 0.005) and weight-for-age z scores (- 0.44 ± 1.15 vs. 0.12 ± 1.15; p = 0.002). The multivariate multiple linear regression analysis showed that height-for-age z scores are independently influenced by monthly per capita family income (β = 0.145; p = 0.003), female gender (β = 0.117; p = 0.015), and infections with A. lumbricoides (β = - 0.141; p = 0.006) and Entamoeba coli (β = - 0.100; p = 0.043). Weight-for-age z scores are influenced by monthly per capita family income (β = 0.175; p < 0.001), female gender (β = 0.123; p = 0.010), and infections with A. lumbricoides (β = - 0.127; p = 0.012), and Entamoeba coli (β = - 0.101; p = 0.039). Monthly per capita family income (β = 0.102; p = 0.039) and female gender (β = 0.134; p = 0.007) positively influences mid upper arm circumpherence., Conclusions: Intestinal parasitism and low family income negatively influence the physical development of children in low-income communities in different Brazilian regions.

Background: Entamoeba species harbored by humans have different degrees of pathogenicity. The present study explores the intra- and interspecific diversity, phylogenetic relationships, prevalence and distribution of tetra- and octonucleated cyst-producing Entamoeba in different Brazilian regions., Methods: Cross-sectional studies were performed to collect fecal samples (n = 1728) and sociodemographic data in communities located in four Brazilian biomes: Atlantic Forest, Caatinga, Cerrado, and Amazon. Fecal samples were subjected to molecular analysis by partial small subunit ribosomal DNA sequencing (SSU rDNA) and phylogenetic analysis., Results: Light microscopy analysis revealed that tetranucleated cysts were found in all the studied biomes. The highest positivity rates were observed in the age group 6-10 years (23.21%). For octonucleated cysts, positivity rates ranged from 1 to 55.1%. Sixty SSU rDNA Entamoeba sequences were obtained, and four different species were identified: the octonucleated E. coli, and the tetranucleated E. histolytica, E. dispar, and E. hartmanni. Novel haplotypes (n = 32) were characterized; however, new ribosomal lineages were not identified. The Entamoeba coli ST1 subtype predominated in Atlantic Forest and Caatinga, and the ST2 subtype was predominant in the Amazon biome. E. histolytica was detected only in the Amazon biome. In phylogenetic trees, sequences were grouped in two groups, the first containing uni- and tetranucleated and the second containing uni- and octonucleated cyst-producing Entamoeba species. Molecular diversity indexes revealed a high interspecific diversity for tetra- and octonucleated Entamoeba spp. (H ± SD = 0.9625 ± 0.0126). The intraspecific diversity varied according to species or subtype: E. dispar and E. histolytica showed lower diversity than E. coli subtypes ST1 and ST2 and E. hartmanni., Conclusions: Tetra- and octonucleated cyst-producing Entamoeba are endemic in the studied communities; E. histolytica was found in a low proportion and only in the Amazon biome. With regard to E. coli, subtype ST2 was predominant in the Amazon biome. The molecular epidemiology of Entamoeba spp. is a field to be further explored and provides information with important implications for public health.

Soil-transmitted helminthiasis (STHs) are poverty-related diseases with high prevalence rates in developing countries. The present study aims to describe the epidemiological scenario of STHs in an urban population in the Brazilian Amazon. A cross-sectional survey ( n  = 349 children aged 1-15 years) was carried out to obtain faecal samples and sociodemographic and sanitation data. Among the children, 143 (41%) were positive for at least one STH. Prevalence rates of infections by A. lumbricoides , T. trichiura , and hookworms were 24.4%, 42.6%, and 9%, respectively. A logistic regression multivariate model showed that infection with A. lumbricoides is significantly more frequent in children aged 11-15 years (odds ratio [OR] = 2.38; 95% confidence interval [CI] = 1.15-4.94; p =0.018) and the presence of latrines inside houses is a protection factor against ascariasis (OR = 0.38; 95% CI = 0.17-0.85; p =0.019). Positivity for T. trichiura is higher in the 5-10 (OR = 3.31; 95% IC = 1.85-5.89; p =0.001) and 11-15 age groups (OR = 3.16; 95% IC = 1.66-6.00; p =0.001), in children living in poor families (OR = 1.78; 95% IC = 1.01-3.14; p =0.045) and practicing open evacuation (OR = 2.07; 95% IC = 1.07-3.99; p =0.029). Hookworm infection is more frequent in children aged 11-15 years (OR = 6.70; 95% IC = 1.91-23.43; p =0.002), males (OR = 6.35; 95% IC = 2.00-20.14; p =0.002), and those living in stilt houses (OR = 3.52; 95% IC = 1.22-10.12; p =0.019). The use of albendazole in the last six months was a protection factor against hookworm infection (OR = 0.31; 95% IC = 0.10-0.96; p =0.042). The proportion of mild, moderate, and severe infections was 55.2%, 37.8%, and 7%, respectively, for A. lumbricoides , 72.4%, 24.3%, and 3.3% for T. trichiura , and 93.8%, 3.1%, and 3.1% for hookworms. Significantly higher worm burdens in T. trichiura and hookworm infections were associated with practicing open defecation and living in stilt houses. The data points to the need to improve sanitation infrastructure in Amazonian cities with similar sociodemographic and environmental characteristics., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Deiviane Aparecida Calegar et al.)

This study aims to assess the prevalence, distribution, and etiological profile of intestinal parasitism in children living in periurban areas in Cachoeiras de Macacu, Rio de Janeiro, Brazil. A community-based cross-sectional survey ( n  = 479) was carried out. Prevalence of infection with G. duodenalis and E. histolytica / E. dispar was 8.6% ( n  = 41) and 13.4% ( n  = 64), respectively. Infection with G. duodenalis was significantly more frequent among children living in poor families (24/187 (12.8%) vs. 16/272 (5.9%); prevalence ratio (PR) = 2.18; 95% confidence interval (CI) = 1.19-3.99; p =0.011). This difference was also significant for infection with any pathogenic parasite (43/187 (23%) vs. 40/272 (14/7%); PR = 1.56; 95% CI = 1.06-2.30; p =0.026). In addition, people residing in houses with more than four inhabitants showed significantly higher positivity for infections with G. duodenalis and with E. histolytica / E. dispar (22/138 (15.9%) vs. 16/311 (5.1%); PR = 3.09; 95% CI = 1.68-5.71; p < 0.001 for G. duodenalis and 32/138 (23.2%) vs. 30/311 (9.6%); PR = 2.40; 95% CI = 1.52-3.79; p < 0.001 for E. histolytica / E. dispar ). Laboratory diagnosis of protozoan enteric infections and effective drugs for their treatment are unmet goals in the primary health care system. Therefore, giardiasis and amebiasis are neglected conditions., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Deiviane A. Calegar et al.)

In this study, we assessed the genetic diversity of Ascaris lumbricoides / Ascaris suum circulating in humans and pigs, exploring potential zoonotic cycles in endemic areas in Brazil. We carried out cross-sectional surveys in four municipalities: Santa Isabel do Rio Negro (SIRN-AM) (n = 328); Nossa Senhora de Nazaré (NSN-PI) and Teresina (TER-PI) (n = 605 and n = 297, respectively); and Cachoeiras de Macacu (CAM-RJ) (n = 543). We also studied 61 fecal samples/adult worms obtained from pigs (n = 53 in NSN-PI and n = 8 in TER-PI). A ~450 bp fragment of the Ascaris cytochrome c oxidase subunit 1 (cox1) and ~400 bp of the NADH dehydrogenase subunit 1 (nad1) were amplified and sequenced. Maximum-likelihood (ML) tree and Median-joining (MJ) haplotype network analyses were performed. We also performed scanning electron micrographs of adult specimens. Positivity rates were 93/328 (28.4%) in SIRN-AM, 6/297 (2.0%) in TER-PI, 0/605 (0%) in NSN-PI, and 6/543 (1.1%) in CAM-RJ. In NSN-PI it reached 11/53 (20.7%) in pigs. The MJ network based on cox1 locus (383 bp) revealed three main clusters, one centered around haplotypes H01/H28/H32 and the other around H07/H11. The cox1 haplotypes had a heterogeneous distribution, showing no pattern by geographic region, and high haplotype diversity. The ML trees based on cox1 and nad1 loci showed a similar topology with each other, and with the haplotype networks. Three distinct clusters were observed. Sequences of cox1 and nad1 from humans and animals were distributed throughout the tree and it was not possible to differentiate specimens of human and swine origin. Ascaris populations obtained from humans and swine in different Brazilian regions are not discriminable through the genetic markers used, which indicates the potential for zoonotic transmission and the need for better control of these infections in swine herds, mainly when created in a peridomestic environment., Competing Interests: The authors have declared that no competing interests exist.

Hookworm infection persists focally in rural communities in Brazil. In this study, we analyze the mitochondrial nucleotide sequences obtained from hookworms infecting humans in order to characterize species composition and assess their genetic diversity and phylogenetic relationships. Field expeditions and cross-sectional surveys were carried out in three Brazilian municipalities from 2013 to 2017: Nossa Senhora de Nazaré (n = 605) and Teresina (n = 297), in the state of Piauí, and Russas (n = 213) in the State of Ceará. Parasitological methods were used to evaluate fecal samples. Hookworm-positive samples had a partial mtDNA cox1 amplified and sequenced. Maximum-likelihood and Bayesian analysis demonstrated two strongly-supported clades, including Group A, corresponding to Necator americanus, and Groups B and C, corresponding to Necator sp. Group A was divided into three main clusters: A1 grouped with Asian sequences, A2 grouped with African sequences, and A3 had only Asian sequences. Group B was closely related to Necator sp., showing a sequence similarity of 98%-99% with African samples circulating zoonotically among humans and non-human primates. Twenty three N. americanus haplotypes were identified. N. americanus Median-Joining network revealed three distinct groups, designated again as A1, A2, and A3. Group A1 presented a star-like shape, with one dominant haplotype. The molecular dating suggested that the two clades dividing N. americanus and Necator sp. began to diverge during the middle Pleistocene. The most recent common ancestor among N. americanus groups was dated to the late Pleistocene. Hookworms circulating in the studied communities are structured in well-defined subpopulations presenting both Asian and African genetic backgrounds. This reveals a double origin for hookworms in northeastern Brazil and opens up new possibilities in phylogeographic, evolutionary, and molecular epidemiological studies in regions where hookworms persists focally, despite control efforts. The presence of potentially zoonotic species and the specific identification of Necator sp. should be further investigated., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Despite the reduction in the prevalence of soil-transmitted helminthiases in many regions of the world, morbidity rates remain high in some rural regions. The Kato-Katz technique is a simple, inexpensive and field-applicable tool commonly used for the diagnosis and worm-burden characterization of these infections. Molecular studies have revolutionized our understanding of the epidemiology and evolutionary genetics of parasites. In this study we recovered helminthic DNA from Kato-Katz slides (n = 93) prepared in 2011 in the Brazilian Amazon. We achieved DNA recovery by polymerase chain reaction (PCR) in 84% of cases for Ascaris sp. and 75% of cases for hookworms. The sequencing confirmed the specific species of the amplicons. The slides stored for a few years could be analysed using this methodology, allowing access to DNA from a large collection of samples. We must consider the Kato-Katz thick smears as a source of helminth DNA. This can significantly reduce logistical difficulties in the field in terms of obtaining, preserving, transporting and initial processing of samples.

Giardia duodenalis has a wide genetic variety, and its characterization helps in the understanding of its transmission dynamics and in the development control strategies. This study aimed to assess the genetic diversity of G. duodenalis obtained in different Brazilian biomes and estimate their phylogenetic relationships. Three surveys including 944 participants were carried out in the municipalities of Russas (RSS, Caatinga semiarid biome), Santa Isabel do Rio Negro (SIRN, Amazon rainforest biome) and Nossa Senhora de Nazaré (NSN, Cerrado-Caatinga transition biome). G. duodenalis-positive fecal samples were submitted to amplification of gene fragments encoding β-giardin (βG, N = 71), glutamate dehydrogenase (GDH, N = 42), and triosephosphate isomerase (TPI, N = 27). Overall detection rates of assemblage A in G. duodenalis-positive samples through βG, GDH and TPI were 22/71 (31%), 13/42 (31%), and 13/27 (48.1%), respectively. Concerning assemblage B, rates with distinct genetic markers were 49/71 (69%), 29/42 (69%), and 14/27 (51.9%), respectively. In the Amazon, assemblage B was more prevalent (77.8%, 71.8% and 65% through βG, GDH and TPI, respectively), while in the Cerrado biome assemblage A predominated (50%, 66.6%, and 85.7%, through βG, GDH and TPI, respectively). In Caatinga biome assemblage A also predominated (71.4%, through βG). Thirty new sub-assemblages are described for assemblage B (24 βG and six TPI), as well as three new sub-assemblages are described for assemblage A (one GDH and 2 TPI). Higher genetic diversity of assemblage B in the Amazon may be related to demographic concentration leading to a more complex transmission network within a poorer sanitation background. The high genetic divergence between assemblages A and B (5.5-6.3%) support the proposal of taxon separation in distinct species., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This study aims to describe the prevalence, distribution, and factors associated with soil-transmitted helminthiases (STHs) in rural localities in Piaui, Brazil. Two cross-sectional surveys (n=605 subjects; 172 families) were carried out in order to obtain socio-demographic, anthropometric, spatial and parasitological data. Parasites were evaluated using Kato-Katz and centrifugal sedimentation techniques. Eggs were measured to assess infection with zoonotic Strongylida parasites. Kernel maps were constructed with Q-GIS. The prevalence of hookworm infection was 12.4% (75/605). Other helminthes found were Trichuris trichiura (n=1; 0.2%) and Hymenolepis nana (n=1; 0.2%). The hookworm positivity rate was significantly lower among subjects who had used albendazole when compared with individuals who had not used anthelmintics or had used antiprotozoal drugs in the last 6 months (8/134 [6.0%] vs. 59/415 [14.2%]; p=0.009). A total of 39/172 (22.7%) families had at least one infected member. The association between the number of dwellers and hookworm positivity in the family was present in a logistic regression multivariate model. Assessment of worm burdens showed 92.2% light, 6.2% moderate, and 1.6% heavy infections. Hookworm eggs (n=34) measured 57.2 - 75.4 µm in length and 36.4 - 44.2 µm in width (mean ± SD = 65.86 ± 4.66 µm L and 40.05 ± 1.99 µm W), commensurate with human hookworms. Hotspots suggest that transmission has a focal pattern. STHs persist in impoverished rural areas in Northeastern Brazil where currently available control strategies (mass drug administration) apparently do not allow the elimination of the infection.

Introduction: The present study aimed to determine the prevalence and factors associated with Giardia intestinalis infection, verifying its impact on the nutritional status of children in northeastern Brazil., Methodology: A cross-sectional study was conducted to obtain parasitological, sociodemographic, and anthropometric data in two municipalities in the states of Piauí and Ceará, northeastern Brazil., Results: Prevalence of giardiasis was 55/511 (10.8%). G. intestinalis was more frequent in people living in poverty (30/209 [14.4%], p = 0.041), performing open evacuation (26/173 [15%], p = 0.034), and drinking rainwater stored in cisterns (9/56 [16.1%], p = 0.005). The proportion of stunting and being underweight in children infected with G. intestinalis was significantly higher than that in uninfected children (5/23 [21.7%] vs. 10/179 [5.6%], p = 0.017, OR = 4.69, 95% confidence interval [CI] = 1.44-15.25 and 5/23 [21.7%] vs. 13/179 [7.3%], p = 0.038, OR = 3.54, 95% CI = 1.13-11.09, respectively). Infection with G. intestinalis remained significantly associated with stunting and being underweight after adjustment for poverty, municipality, sex, and age in a logistic regression multivariate model., Conclusions: In rural areas in northeastern Brazil, giardiasis has acquired great public health importance in the soil-transmitted helminths control era, impacting the nutritional status of children and requiring new approaches to diagnosis and treatment and translational research that could generate applicable solutions at the community level., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2017 Beatriz Coronato-Nunes, Deiviane Aparecida Calegar, Kerla Joeline Lima Monteiro, Lauren Hubert-Jaeger, Elis Regina Chaves Reis, Samanta CC Xavier, Lindsay Nicole Carpp, Marli Maria Lima, Márcio N Bóia, Filipe Anibal Carvalho-Costa.)

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.