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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. Resumo Parasitos do gênero Oesophagostomum causam doenças entéricas e podem afetar a criação de animais, como os suínos. O objetivo deste estudo foi identificar as espécies e explorar a diversidade genética de Oesophagostomum spp. infectando suínos em contato próximo com humanos, no estado do Piauí, Brasil. Oitenta e sete amostras fecais foram coletadas para testes parasitológicos, análise morfométrica dos ovos e análises moleculares. A taxa geral de positividade para ovos estrongiliformes foi de 81,6%. Quarenta e duas amostras de ovos estrongiliformes foram submetidas à PCR e seis sequências cox1 (637 bp) foram identificadas para o gênero Oesophagostomum. As sequências foram identificadas como Oesophagostomum dentatum, O. quadrispinulatum e O. columbianum. Na árvore filogenética e na rede haplotípica, 89 sequências foram separadas em sete clusters, incluindo sequências de referência do GenBank. Oesophagostomum dentatum e O. quadrispinulatum são espécies estreitamente relacionadas e formaram um grupo monofilético com O. aculeatum. Oesophagostomum columbianum apresentou semelhança com sequências de parasitas obtidos de pequenos ruminantes e o clado foi posicionado mais próximo de O. bifurcum. Alta diversidade interespecífica foi encontrada e a diversidade intraespecífica variou de acordo com as espécies. Esse foi o primeiro estudo a caracterizar sequências de DNA de Oesophagostomum isoladas de suínos no Brasil.

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.

O aleitamento materno exclusivo (AME) propicia saúde ao recém-nascido e à mulher, fortalece o vínculo mãe e filho e leva à redução na mortalidade infantil. O objetivo foi identificar o perfil e os conhecimentos sobre aleitamento materno de gestantes atendidas em Unidades Básicas de Saúde (UBS) durante o pré-natal, no município de Gilbués, Piauí, Brasil. Trata-se de um estudo descritivo, com abordagem quantitativa coletada por meio de um questionário sobre características sociodemográficas e conhecimentos em relação ao aleitamento materno. O estudo foi realizado em 40 gestantes nas UBS dos bairros São José e Santo Antônio. Destas, 75% estavam na segunda gestação ou mais e 47,5% no segundo trimestre gestacional. A maioria apresentou idade entre 18 e 30 anos, eram solteiras, possuíam apenas o ensino fundamental, não exerciam atividade profissional e possuíam renda familiar de até um salário mínimo. Quanto aos conhecimentos sobre aleitamento materno, houve orientação no pré-natal, porém com pouca incorporação acerca dos benefícios que o AME também pode proporcionar à mãe. Apontou-se ainda as dúvidas e/ou inseguranças das gestantes sobre amamentação. As atividades de educação em saúde no pré-natal são fundamentais para a saúde da criança e da mulher promovendo estratégias de promoção, apoio e incentivo ao aleitamento materno.

As parasitoses gastrintestinais são os principais obstáculos enfrentados em caprinos, contribuindo para o aumento da mortalidade e consequente queda na produção animal. A presente pesquisa objetivou identificar a prevalência de helmintos gastrintestinais em caprinos de um município do Estado do Piauí. Trata-se de uma pesquisa experimental de natureza quantitativa. Constituiu a população alvo desta pesquisa, 45 caprinos sem raça definida provenientes de uma fazenda situada na zona rural do município de Teresina-PI. Esses animais receberam alimentação e sal mineral, de acordo o padrão recomendado tecnicamente para utilização no rebanho da propriedade. Os 120 animais selecionados para o estudo foram submetidos a exames coproparasitológicos e coprocultura. Independente de sexo, os animais possuem em média dois anos de idade, com peso médio de 38kg ± 500 gr. As fezes para a realização da análise coproparasitológica foram colhidas da ampola retal de cada animal. Os resultados apontaram a prevalência 84% de Haemonchus sp, 0,3% Oesophagostomun sp e 13% de Trichostrongylus sp. Considera-se então, relevante um esquema de vermifugação conforme um protocolo de um profissional, contemplando a região, hábitos, e demais características para direcionamento correto de vermífugos, no caso de soluções específicas.

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.

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. Graphical Abstract

Background In northeastern Brazil, the wild nature of Trypanosoma cruzi vectors has challenged control actions. This study aims to describe the entomological and epidemiological scenario of Chagas disease in rural communities in the state of Piauí. Methods A cross-sectional study (n=683 individuals/244 dwellings) was carried out to obtain serum samples, sociodemographic data and intra- and peridomestic triatomines. Results The overall seroprevalence rate was 8.1%, with no positive tests among subjects 75 y of age, respectively; 1474 triatomines were collected, of which 90.3% were found in peridomiciliary structures and 9.7% inside houses; 87.2% were classified as Triatoma brasiliensis. T. cruzi infection rates in insects were 0.5% by light microscopy and 0.9% by culture in NNN/LIT medium. Five cultivated isolates were submitted to molecular genotyping, three of which were identified as T. cruzi I and two as T. cruzi II. Conclusions Although no vector transmission currently occurs, prevalence rates are high in adults and the elderly. This disease should be targeted by primary healthcare providers. Insect surveillance and control activities should not be discontinued in an environment favourable to the perpetuation of house colonization by triatomines.

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.

Nos últimos anos, as infecções sexualmente transmissíveis (IST) vêm aumentando em todo o mundo, principalmente entre adolescentes. Assim, o estudo tem como objetivo investigar o conhecimento que os adolescentes possuem sobre os principais sinais e sintomas das IST. Trata-se de um estudo transversal, descritivo, interpretativo, com abordagem quantitativa. O estudo foi realizado em uma Escola Técnica Pública de Ensino Médio do Nordeste do Brasil por meio de questionário online. Esta análise foi composta por 595 alunos. O estudo mostra que a maioria dos alunos (73,6%) não sabia quais eram os principais sinais e sintomas das IST. As mulheres tiveram mais informações sobre o assunto do que os homens. O artigo demonstra que os alunos não possuem conhecimento adequado sobre os principais sinais e sintomas das IST e isso é preocupante, pois se encontram na fase de iniciação sexual.

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 Nazare (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.

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 Nazare (n = 605) and Teresina (n = 297), in the state of Piaui, and Russas (n = 213) in the State of Ceara. 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.

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.

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.

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 Nazare (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.

Introduction: The present study aimed to determine the prevalence and factors associated with Giardia intestinalisinfection, 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 Piaui and Ceara, northeastern Brazil. Results: Prevalence of giardiasis was 55/511 (10.8%). G. intestinaliswas 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. intestinaliswas 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. intestinalisremained 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.

Background Current control policies for intestinal parasitosis focuses on soil-transmitted helminths, being ineffective against Giardia intestinalis, a highly prevalent protozoon that impacts children’s nutritional status in developing countries. The objective of this study was to explore spatial and molecular epidemiology of Giardia intestinalis in children of Amerindian descent in the Brazilian Amazon. Methodology/Principal Findings A cross sectional survey was performed in the Brazilian Amazon with 433 children aged 1 to 14 years. Fecal samples were processed through parasitological techniques and molecular characterization. Prevalence of G. intestinalis infection was 16.9% (73/433), reaching 22.2% (35/158) among children aged 2–5 years, and a wide distribution throughout the city with some hot spots. Positivity-rate was similar among children living in distinct socioeconomic strata (48/280 [17.1%] and 19/116 [16.4%] below and above the poverty line, respectively). Sequencing of the β-giardin gene revealed 52.2% (n = 12) of assemblage A and 47.8% (n = 11) of assemblage B with high haplotype diversity for the latter. The isolates clustered into two well-supported G. intestinalis clades. A total of 38 haplotypes were obtained, with the following subassemblages distribution: 5.3% (n = 2) AII, 26.3% (n = 10) AIII, 7.9% (n = 3) BIII, and 60.5% (n = 23) new B genotypes not previously described. Conclusions/Significance Giardia intestinalis infection presents a high prevalence rate among Amerindian descended children living in Santa Isabel do Rio Negro/Amazon. The wide distribution observed in a small city suggests the presence of multiple sources of infection, which could be related to environmental contamination with feces, possibly of human and animal origin, highlighting the need of improving sanitation, safe water supply and access to diagnosis and adequate treatment of infections.

Acute febrile diseases are common and often associated with infectious agents in tropical countries such as Brazil. With nonspecific clinical manifestations and hard to differentiate with a number of endemic diseases such as dengue, leptospirosis, and other fatal diseases, Brazilian spotted fever has rarely been considered in the diagnosis, fact that with the consequent delay in the specific antimicrobial treatment, has determined high lethality often observed in our country. In this article the authors discuss the difficulty of the differential diagnosis of FMB with dengue, one of the most important and frequent infectious diseases in Brazil, where epidemics are reported regularly and the possibility of errors in diagnosis due to clinical similarity is a reality.

A new epidemiological scenario involving the oral transmission of Chagas disease, mainly in the Amazon basin, requires innovative control measures. Geospatial analyses of the Trypanosoma cruzi transmission cycle in the wild mammals have been scarce. We applied interpolation and map algebra methods to evaluate mammalian fauna variables related to small wild mammals and the T. cruzi infection pattern in dogs to identify hotspot areas of transmission. We also evaluated the use of dogs as sentinels of epidemiological risk of Chagas disease. Dogs (n = 649) were examined by two parasitological and three distinct serological assays. kDNA amplification was performed in patent infections, although the infection was mainly sub-patent in dogs. The distribution of T. cruzi infection in dogs was not homogeneous, ranging from 11–89% in different localities. The interpolation method and map algebra were employed to test the associations between the lower richness in mammal species and the risk of exposure of dogs to T. cruzi infection. Geospatial analysis indicated that the reduction of the mammal fauna (richness and abundance) was associated with higher parasitemia in small wild mammals and higher exposure of dogs to infection. A Generalized Linear Model (GLM) demonstrated that species richness and positive hemocultures in wild mammals were associated with T. cruzi infection in dogs. Domestic canine infection rates differed significantly between areas with and without Chagas disease outbreaks (Chi-squared test). Geospatial analysis by interpolation and map algebra methods proved to be a powerful tool in the evaluation of areas of T. cruzi transmission. Dog infection was shown to not only be an efficient indicator of reduction of wild mammalian fauna richness but to also act as a signal for the presence of small wild mammals with high parasitemia. The lower richness of small mammal species is discussed as a risk factor for the re-emergence of Chagas disease., Author Summary The classical methodology of mapping works with discrete units and sharp boundaries does not consider gradient transition areas. Spatial analysis by the interpolation method, followed by map algebra, is able to model the spatial distribution of biological phenomena and their distribution and eventual association with other parameters or variables, with a focus on enhancing the decision power of responsible authorities. Acute Chagas Disease outbreaks are increasing in the Amazon Basin as result of oral transmission. This scenario requires a new approach to identify hotspot transmission areas and implement control measures. We applied a geospatial approach using interpolation and map algebra methods to evaluate mammalian fauna variables related to these outbreaks. We constructed maps with mammalian fauna variables including the infection rates by Trypanosoma cruzi, in dogs and small wild mammals. The results obtained by visual examination of the maps were validated by statistical analysis. We observed that high prevalence of T. cruzi infection in dogs and small wild mammals was associated with mammal lower richness. Monitoring of T. cruzi infection in dogs may be a valuable tool for detecting the fauna lower richness of small wild mammals and elucidating the transmission cycle of T. cruzi in the wild.