Prevalence of Entamoeba histolytica/Entamoeba dispar in the city of Campina Grande, in northeastern Brazil

Intestinal polyparasitism and levels of mucosal anthelmintic SIgA in children from endemic areas in Northeastern Brazil

Interactions between parasites during co-infections are often complex and can impact immunization and treatment programmes, as well as disease outcomes and morbidity. However, little is known about these interactions and the mechanisms involved. In this study, a coproparasitological survey was carried out in school-age children living in endemic areas of parasitic infection in the state of Sergipe, Northeastern Brazil. Anti-helminth-specific and total secretory immunoglobulin-A (SIgA) levels were measured in stool and saliva samples and were compared in children presenting monoparasitism, polyparasitism (helminths and/or intestinal protozoa) and no infections. The survey showed that protozoa were more prevalent than helminths, and that there was a high frequency of polyparasitism in the studied population, mainly from combinations of protozoan species. Although less frequent, combinations between species of protozoa and helminths were also observed. The levels of salivary SIgA in these co-infected individuals were lower than the average observed in infections with helminths alone. Although the children participating in this survey were asymptomatic, and it was, therefore, not possible to evaluate the impact of salivary SIgA reduction on the diseases, and the study highlights the need for further investigations of co-infections by intestinal parasites and the effects on immune response induced by the interactions between different parasites.

Diversity, geographical distribution, and prevalence of Entamoeba spp. in Brazil: a systematic review and meta-analysis

The genus Entamoeba includes a variety of widely distributed species adapted to live in the digestive tracts of humans and a large variety of animals of different classes. The objective of this study was to investigate the prevalence, distribution, and molecular epidemiology of Entamoeba spp. in different classes of hosts in Brazil. Studies that analyzed hosts from several classes, including humans and domestic, wild, or captive animals, were considered. The pooled prevalence of Entamoeba spp. was calculated using the random-effects model. A total of 166 studies on humans and 16 on animals were included. The prevalence of Entamoeba spp. in the Brazilian population was 22% (95% CI: 21–24). The state with the highest prevalence was Paraiba with 72%, followed by Federal District with 53%, and Rondonia with 50%. In immunocompromized patients, the prevalence was 18%, and cancer (36%) was the most prevalent cause of immunosuppression. The prevalence of Entamoeba spp. in animal hosts was 12% (95% CI: 7–17). Captive wild animals and domestic farm animals showed the highest prevalence, with 16% and 15%, respectively. The species found more often were E. coli (86.5%), E. dispar (7.9%), and E. histolytica (3.1%). In conclusion, a high prevalence (22%) of Entamoeba spp. was found in the Brazilian population, with a prevalence of up to 50% mainly in the northern, northeastern, and central-western regions. The pathogenic species E. histolytica is distributed in most Brazilian regions, with significant prevalence percentages. Among animals, unidentified Entamoeba species were most prevalent in mammals.

Epidemiology, species composition and genetic diversity of tetra- and octonucleated Entamoeba spp. in different Brazilian biomes

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04672-y.

Occurrence of zoonotic gastrointestinal parasites of rodents and the risk of human infection in different biomes of Brazil

Rodents are synanthropic mammals adapted to several ecosystems, where they can contribute to the transmission of zoonotic pathogens, including gastrointestinal parasites. The aim of this study was to study the occurrence of gastrointestinal parasites from rodents and discuss the risk of transmission to humans. Fecal samples (n = 110) from different rodent species, namely, Cerradomys subflavus (n = 4), Mus musculus (n = 14), Rattus norvegicus (n = 80), Rattus rattus (n = 8) and Thrichomys apereoides (n = 4), were analyzed using the FLOTAC technique. Of the samples examined, 73.6% (81/110) tested positive for at least one gastrointestinal parasite. The most commonly identified parasites were Aspiculuris sp., Hymenolepis nana, Moniliformis sp., Syphacia sp., Strongyloides spp., Taenia spp., and Trichuris spp. eggs, Angiostrongylus cantonensis larvae and Entamoeba spp. cysts. The findings of this study demonstrate that rodents living in different Brazilian biomes are parasitized by a wide range of parasites, including some of public health concern. Therefore, the proximity of rodents to human settlements may represent a tangible risk of infection for people living in these areas.

Molecular detection and genotyping of intestinal protozoa from different biogeographical regions of Colombia

Background

Intestinal parasitic protozoa represent a serious problem of public health particularly in developing countries. Protozoa such as Blastocystis, Giardia intestinalis, Entamoeba histolytica and Cryptosporidium spp. are associated with diarrheal symptoms. In Colombia, there is little region-specific data on the frequency and circulating genotypes/species of these microorganisms. Therefore, the main objective of our study was to employ molecular detection and genotyping of G. intestinalis and Blastocystis, Cryptosporidium and Entamoeba spp. in samples from different biogeographical regions of Colombia.

Methods

We collected 649 human fecal samples from five biogeographical regions of Colombia: the Amazon, Andean, Caribbean, Orinoco and Pacific regions. Blastocystis, G. intestinalis, Cryptosporidium spp. and Entamoeba complex were detected by microscopy and conventional PCR. Molecular genotyping was conducted to identify Blastocystis subtypes (STs) (18s), G. intestinalis assemblages (triose phosphate isomerase and glutamate dehydrogenase) and Cryptosporidium species (18s). Genetic diversity indices were determined using dnasp.5.

Results

We detected G. intestinalis in 45.4% (n = 280) of samples, Blastocystis in 54.5% (n = 336) of samples, Cryptosporidium spp. in 7.3% (n = 45) of samples, Entamoeba dispar in 1.5% (n = 9) of samples, and Entamoeba moshkovskii in 0.32% (n = 2) of samples. Blastocystis STs 1–4, 8 and 9 and G. intestinalis assemblages AII, BIII, BIV, D and G were identified. The following Cryptosporidium species were identified: C. hominis, C. parvum, C. bovis, C. andersoni, C. muris, C. ubiquitum and C. felis. The Caribbean region had the highest frequency for each of the microorganisms evaluated (91.9% for G. duodenalis, 97.3% for Blastocystis, 10.8% for Cryptosporidium spp., 13.5% for E. dispar and 2.7% for E. moshkovskii). The Orinoco region had a high frequency of Blastocystis (97.2%) and the Andean region had a high frequency of G. intestinalis (69.4%). High and active transmission was apparent in several regions of the country, implying that mechanisms for prevention and control of intestinal parasitosis in different parts of the country must be improved.

Socioeconomic and parasitological aspects in Quilombola communities in two of the oldest municipalities in Brazil

Objective To carry out a socioeconomic, demographic and parasitological evaluation of quilombola communities in two of the oldest municipalities in Brazil.Material and Methods Between December 2015 and June 2016, of the total of 231 residents of the communities, socioeconomic questionnaires were applied and fecal samples collected from 150 individuals were analyzed by spontaneous sedimentation method and the Kato-Katz method.Results It was observed that 95.3% (n=143) of the interviewees had piped water at their residence, and 76% (n=114) came from wells or springs; 85.3% (n=128) reported that the toilet drain was made in a rudimentary septic tank and 59.3% (n=89) reported having litter buried or burned, showing precarious conditions in basic sanitation. Still on socioeconomic aspects, 80.7% (n=121) of the individuals reported having access to the public health service. Parasitological tests were positive for 48% (n=72) of the analyzed samples, and 25% (n=18) had two or more parasites. The most frequent organism in the study population was the commensal Entamoeba coli (55.6%, n=40), followed by Ascaris lumbricoides (19.4%, n=14) and the commensal Endolimax nana (16.7%, n=12). The Poisson regression showed an increase of 1.59 in the prevalence of parasites for individuals who do not have access to the public health service, when compared to those who have access to these services.Conclusions The results indicate the need to implement public health measures in order to reduce, prevent and treat the parasitological condition of the population to obtain better conditions and quality of life.

The state of art of neutrophil extracellular traps in protozoan and helminthic infections

Neutrophil extracellular traps (NETs) are DNA fibers associated with histones, enzymes from neutrophil granules and anti-microbial peptides. NETs are released in a process denominated NETosis, which involves sequential steps that culminate with the DNA extrusion. NETosis has been described as a new mechanism of innate immunity related to defense against different pathogens. The initial studies of NETs were carried out with bacteria and fungi, but currently a large variety of microorganisms capable of inducing NETs have been described including protozoan and helminth parasites. Nevertheless, we have little knowledge about how NETosis process is carried out in response to the parasites, and about its implication in the resolution of this kind of disease. In the best case, the NETs entrap and kill parasites in vitro, but in others, immobilize the parasites without affecting their viability. Moreover, insufficient studies on the NETs in animal models of infections that would help to define their role, and the association of NETs with chronic inflammatory pathologies such as those occurring in several parasitic infections have left open the possibility of NETs contributing to pathology instead of protection. In this review, we focus on the reported mechanisms that lead to NET release by protozoan and helminth parasites and the evidence that support the role of NETosis in the resolution or pathogenesis of parasitic diseases.

Molecular identification of Entamoeba histolytica from stool samples of Ilam, Iran

INTRODUCTION

Amoebiasis is a multifactorial, life-threatening public health issue and the third parasitic disease cause of mortality in worldwide, particularly in low- and mid-income countries. The aim of this study was to attempt to explore genetic encoding differences of CP8 (conserved gene) of Entamoeba histolytica/Entamoeba dispar in its various infectious properties isolated from Ilam located at a southwest part of Iran.

MATERIALS AND METHODS

A total of 2023 stool samples were collected between 2016 and 2018 from the hospital in Ilam, of which only 30 isolates were identified as E. histolytica/E. dispar. These isolates were collected from the intensive care unit, infectious disease, and surgery settings. The isolates were identified and the polymerase chain reaction (PCR) was performed to detect the CP8 gene. In all stages, Entamoeba histolytica HM1: IMSS was used as a positive control.

RESULTS

In genotype confirmation, only two isolates had the CP8 gene found in the PCR technique. The sequencing results confirmed the mentioned gene with 99%-100% specificity.

CONCLUSION

It is concluded that PCR is highly sensitive to detect E. histolytica and indicating this important role as screening tools in direct DNA extraction from stool samples and valuable technique in early detection of symptomatic and asymptomatic E. histolytica patients.

Prevalence of Entamoeba histolytica and other enteral parasitic diseases in the metropolitan region of Belo Horizonte, Brazil. A cross-sectional study

BACKGROUND

Enteral parasitic diseases are a public health problem in nations with low economic development and in settings with poor sanitation. Amebiasis is the second most frequent form of parasitosis, with a high burden of disease. Knowledge of the prevalence of enteroparasitoses in a given region is useful for planning clinical decision-making. Thus, the aim of this study was to estimate the prevalence of enteral parasitic diseases, especially amebiasis, through analysis on stool samples from public and private laboratories in a metropolitan area in southeastern Brazil.

DESIGN AND SETTING

Cross-sectional study conducted in the metropolitan region of Belo Horizonte, Brazil.

METHODS

We evaluated 6,289 fecal samples from one private and one public laboratory. The samples were concentrated by means of spontaneous sedimentation, and those that were positive for Entamoeba histolytica or Entamoeba dispar in optical microscopy analyses were processed to obtain deoxyribonucleic acid, with subsequent identification through the polymerase chain reaction.

RESULTS

Among the stool samples, 942 (15.0%) had parasitic infections; 73 (1.2%) of these were helminthic infections and 847 (13.5%) were protozoan infections, caused mainly by Escherichia coli (6.0%), Endolimax nana (5.2%) and Giardia lamblia (1.2%). Infections due to Entamoeba histolytica or Entamoeba dispar occurred in 36 samples (0.6%) and the polymerase chain reaction revealed five (13.9%) as Entamoeba histolytica.

CONCLUSION

The prevalence of enteral parasitic diseases is high in the metropolitan region of Belo Horizonte, although amebiasis may not be a problem.