Mônica Cristina de Moraes Silva

Invasive amebiasis: an update on diagnosis and management

In its invasive form, the trophozoite is responsible for clinical syndromes, ranging from classical dysentery to extraintestinal disease with emphasis on hepatic amebiasis. Abdominal pain, tenderness and diarrhea of watery stool, sometimes with blood, are the predominant symptoms of amebic colitis. Besides the microscopic identification of Entamoeba histolytica, diagnosis should be based on the detection of specific antigens in the stool or PCR associated with the occult blood in the stool. Amebic dysentery is treated with metronidazole, followed by a luminal amebicide. The trophozoite reaches the liver causing hepatic amebiasis. Right upper quadrant pain, fever and hepatomegaly are the predominant symptoms. The diagnosis is made by the finding of E. histolytica in the hepatic fluid, or in the necrotic material at the edge of the lesion in a minority of patients, and by detection of antigens or DNA. Ultrasonography is the initial imaging procedure indicated. The local perforation of hepatic lesion leads to important and serious complications.

Determinação da infecção por Entamoeba histolytica em residentes da área metropolitana de Belém, Pará, Brasil, utilizando ensaio imunoenzimático (ELISA) para detecção de antígenos

The epidemiological status of amebiasis has been reevaluated since Entamoeba histolytica (pathogenic) was considered a distinct species from Entamoeba dispar (non-pathogenic). We investigated E. histolytica antigens in stool samples from residents of Belém, Para State, Brazil, with commercially available enzyme-linked immunosorbent assay (E. histolytica Test, TechLab Inc., Blacksburg, USA). A total of 845 samples were analyzed, of which 248 were positive (29.35%). E. histolytica infection was more frequent in the over-14-year age group (30.36%) than in the 0-14-year group (28.28%), but the difference was not statistically significant (p < 0.05). Of all the samples, 334 were also submitted to parasitological methods (direct, Hoffman, and Faust et al.). There were discordant results between ELISA and parasitological methods in 83 samples (24.85%), with more positive results using ELISA. Our results thus suggest that intestinal amebiasis is an important public health problem in Greater Metropolitan Belém.

Alterações clínicolaboratoriais em pacientes com malária por Plasmodium vivax e deficiência de glicose-6-fosfato desidrogenase tratados com 0,50mg/kg/dia de primaquina

O efeito adverso da primaquina na dose de 0,50mg/kg/dia foi investigado em onze pacientes com malaria vivax (tres com deficiencia de glicose-6-fosfato desidrogenase). Alteracoes clinicas e laboratoriais indicaram hemolise aguda apenas nos enzimopenicos, o que fez com que o tratamento fosse interrompido. Nossos resultados sugerem a necessidade do emprego de um teste de triagem para a deficiencia de G6PD em areas endemicas de malaria vivax a fim de se evitar complicacoes causadas pelo uso da primaquina.

Diagnosis of intestinal amebiasis using coproscopic and immunological methods in a population sample in Greater Metropolitan Belém, Pará, Brazil

We compare diagnostic methods for Entamoeba histolytica in fecal samples from the city of Belém, Pará, Brazil. We analyze stool samples from children and adults (Group I); stool and serum samples from adults (Group II); and stool samples from children (Group III). In groups I and III, we used direct examination with lugol (DM), Faust et al (FM), and ELISA (detection of E. histolytica anti-GIAP coproantigen) and in group II, DM, iron hematoxylin staining (IHS), FM, ELISA, and the indirect immunofluorescence test (IFAT) for detection of IgG antibodies. Positivity was 10.50% by DM plus FM and 28.99% by ELISA. There was no correlation between positivity and age group. In Group II (n = 87), the positive rate was 4.59% by DM plus FM, 8.04% by IHS, 4.59% by IFAT, and 21.83% by ELISA. The ELISA test was the most sensitive for all groups. IFAT alone is still not a useful tool for diagnosis of E. histolytica infection. The ELISA test is simple, performed in one-third of cases used for IHS and IFAT, and greatly improves quality of diagnosis. We recommend this as the method of choice for diagnosis of suspected E. histolytica infection.

High prevalence of G12P[8] rotavirus strains in Rio Branco, Acre, Western Amazon, in the post‐rotavirus vaccine introduction period

The present study aimed to provide a molecular characterization of circulating rotavirus (RVA) strains in Rio Branco, Acre, in the post‐rotavirus vaccination period, particularly with regard to the emerging, increasingly prevalent G12P[8] genotype. A total of 488 fecal specimens from diarrheic and non‐diarrheic children were obtained between January and December 2012. RVA detection was initially performed using enzyme‐linked immunosorbent assay (ELISA) method, followed by reverse‐transcription polymerase chain reaction (RT‐PCR) using specific primers. RVA was detected in 18.3% (44/241) of the children with acute diarrhea and in 1.2% (3/247) of the non‐diarrheic children (P < 0.001), with overall RVA‐positivity of 9.6% (47/488). The most common genotype was G2P[4] with 43.2% (19/44) of the diarrheic cases, followed by G12P[8] (27.3%, 12/44), G3P[6] (18.2%, 8/44), G3P[8] (4.5%, 2/44), and G12P[6] (2.3%, 1/44). G12 samples belonged to lineage III and were from children aged 4–52 months. All of these children had acute diarrhea associated with fever (83.3%, 10/12) and vomiting (66.7%, 8/12). Most of the cases occurred in August (58.3%, 7/12), 75% (9/12) of which having received the full vaccination scheme with Rotarix™. For the first time G12 was reported at relative high prevalence in Brazil. Our findings warrant further monitoring studies on the molecular characterization of circulating RVA strains after rotavirus vaccine introduction in Brazil and elsewhere, since the occurrence of either unusual our emerging genotypes may pose a challenge to vaccination strategies. J. Med. Virol. 88:782–789, 2016.

Aspectos epidemiológicos das enteroinfecções bacterianas em menores de 5 anos de idade em Rio Branco, estado do Acre, Brasil*

OBJECTIVE: To investigate the occurrence of bacterial enteric pathogens in the etiology of acute diarrheal disease (ADD) in association with clinical and epidemiological aspects in children under 5 years old attended in healthcare units in Rio Branco, Acre State, Brazil, in 2012. MATERIALS AND METHODS: The study analyzed data obtained from clinical and epidemiological records of 502 children, 272 ADD cases and 230 controls. The frequency of each enteropathogen and the association with the socioeconomic conditions of the children were verified using chi-square test and Fishers exact test, with a significance level of 0.05 (5%), and BioEstat v5.0 software. RESULTS: The most frequent bacteria in both groups were diarrheagenic Escherichia coli (80.2%), Campylobacter jejuni and Campylobacter coli (9.0%), Shigella spp. (5.6%), and Salmonella spp. (4.0%). There was a significant correlation between the occurrence of E. coli and ADD (p < 0.001). The temporal distribution of diarrheagenic E. coli was higher in November and December (rainy season). The correlation between family income and the clinical group was statistically significant (p < 0.00051). Regarding housing conditions, a higher risk was observed when the frequency of garbage collection was irregular. The risk of the child developing ADD was greater when mothers were between 14 and 19 years of age. CONCLUSION: It was verified that cases of ADD in children under 5 years old in Rio Branco were related to the circulation of bacterial enteric pathogens, especially diarrheagenic E. coli.