Evaluación de pruebas inmunológicas en el diagnóstico de Giardia duodenalis y Cryptosporidium spp, Honduras / Evaluation of immunologic tests in the diagnosis of Giardia duodenalis and Cryptosporidium spp., Honduras

Antecedentes: No conocemos datos sobre evaluación de pruebas inmunológicas para mejorar el diagnóstico de Giardia duodenalis y Cryptosporidium spp., agentes etiológicos de diarrea de importancia mundial, en Honduras. Objetivos: Comparar dos pruebas inmunológicas para el diagnóstico de Giardia y Cryptosporidium spp. con microscopía de rutina y determinar su aplicabilidad local. Métodos: Estudio descriptivo transversal. En 2013, 134 muestras de heces recibidas en el Servicio de Parasitología del Hospital Escuela (HE) y 67 muestras del Centro de Salud Alonso Suazo (CSAS) se analizaron con una Prueba Rápida Inmunocromatográfica (PDR). En 2019-2020, 60 muestras de heces del HE se analizaron con una prueba inmunoenzimática ELISA. El protocolo de rutina incluyó examen directo en solución salina y solución de Lugol, coloración tricrómica y coloración ácido resistente modificada (ARM) (HE) y examen directo en solución salina y solución de Lugol (CSAS). Resultados: Cada prueba inmunológica mostró mayor positividad que la microscopía: en 134 muestras del HE para Giardia (6.7% vs 4.5%) y Cryptosporidium (3.7% vs 0.7%), similar en 67 muestras del CSAS (14.9% vs 7.5% para Giardia; 0.7% para Cryptosporidium con la prueba inmunológica). De 60 muestras analizadas por ELISA en HE, 31.7% fue positiva por Giardia vs 18.3% en examen directo y 23.3% en coloración tricrómica; 6.7% positiva por Cryptosporidium spp. vs 3.3% por coloración ARM. Discusión: Pruebas inmunológicas aumentaron significativamente el diagnóstico de ambas parasitosis; sin embargo, publicaciones sobre pruebas similares ofrecieron resultados no concluyentes. Por costo elevado podrían reservarse para pacientes pediátricos, pacientes inmunocomprometidos en hospitales, complementando microscopía. Los laboratorios de salud deben fortalecer capacidad diagnóstica...(AU)

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

Giardia duodenalis infection is distributed worldwide and can achieve prevalence around 60%, especially in developing countries. This protozoan is divided into eight assemblages, in which A and B have high zoonotic potential, whereas C to H are host-specific. This scenario is changing as molecular studies progress, highlighting that knowledge on host-specificity still has a long way to go. Understanding the players involved in transmission routes enables rational designs of control strategies. Considering the high prevalence of giardiasis, this review aims to gather together the data on available studies on the distribution of G. duodenalis assemblages in Brazil until September 2020.

Cross-sectional epidemiological investigations of Giardia lamblia in children in Pakistan

ABSTRACT BACKGROUND: The prevalence of Giardia lamblia in Pakistani children is currently unknown. The aim here was to evaluate the prevalence and risk factors of Giardia lamblia in children exhibiting diarrhea. DESIGN AND SETTING: Cross-sectional study at different district healthcare hospitals in Pakistan. METHODS: A total of 800 samples were collected from children aged 0-10 years. Information regarding personal data, demographic data and supposed risk factors was collected through a structured questionnaire. Giardia lamblia was detected through direct microscopy and antigens through the enzyme-linked immunosorbent assay (ELISA). RESULTS: The prevalence of Giardia lamblia was 2.75% through direct microscopy and inflated to 9.5% through ELISA. The demographic factors positively associated with occurrences of giardiasis were age (P = 0.035; odds ratio, OR = 1.96; 95% confidence interval, CI = 1.094-3.533), mother's educational level (P = 0.031; OR = 2.67; 95% CI = 1.186-6.045) and father's educational level (P = 0.004; OR = 3.56; 95% CI = 1.612-7.899). Similarly, among the supposed risk factors, rural residency (P = 0.032; OR = 1.76; 95% CI = 1.098- 2.851), absence of proper sewerage system (P = 0.000; OR = 6.60; 95% CI = 4.029-10.841) and unavailability of safe drinking water (P = 0.000; OR = 4.08; 95% CI = 2.207-7.547) were the factors strongly connected with giardiasis. Abdominal discomfort was a prominent clinical sign with 46% frequency. CONCLUSION: Various risk factors were associated with occurrences of Giardia, thus emphasizing the importance of parents' education, safe drinking water and proper sewerage systems for Pakistani children's health.

Detection of zoonotic and livestock-specific assemblages of Giardia duodenalis in free-living wild lizards / Detecção de genótipos de Giardia duodenalis zoonóticos e específicos de ruminantes domésticos em lagartos selvagens

Abstract Giardia duodenalis is a zoonotic parasite that infects the gut of a wide range of vertebrates, including numerous wildlife species. However, little is known about this protozoan parasite in reptiles. Fecal samples from 31 wild lizards were collected in Galicia (northwest Spain) and screened for the presence of Giardia by PCR amplification and sequencing of the ITS1-5.8S-ITS2 region in the ribosomal unit. This allowed detection of the parasite in 5 samples (16.1%), and enabled identification of G. duodenalis assemblage A2 in two samples of Iberian rock lizard (Iberolacerta monticola), G. duodenalis assemblage B in other two samples of I. monticola, and G. duodenalis assemblage E in one sample of Bocage's wall lizard (Podarcis bocagei). The results obtained after PCR amplification and sequencing of the SSU-rDNA gene confirmed the presence of G. duodenalis assemblage A in two samples of I. monticola. This is the first report of G. duodenalis in free-living lizards, although further studies are needed to distinguish between actual infection and mechanical dissemination of cysts. The detection of zoonotic and livestock-specific assemblages of G. duodenalis demonstrates the wide environmental contamination by this parasite, possibly due to human activities.

Resumo Giardia duodenalis é um parasito zoonótico que infecta o intestino delgado de uma ampla gama de vertebrados, sendo detectado em numerosas espécies selvagens. No entanto, pouco se conhece sobre a presença deste parasito protozoário em répteis. Para estudar a presença de Giardia, foram obtidas amostras fecais provenientes de 31 lagartos e coletadas em diferentes localizações de Galicia (Noroeste da Espanha). Mediante a aplicação da técnica de PCR e posterior sequenciamento da região ITS1-5.8S-ITS2 da unidade ribossômica, detectou-se Giardia em 5 amostras (16,1%), identificando-se o genótipo A2 de G. duodenalis em 2 amostras de lagartos da montanha (Iberolacerta monticola), G. duodenalis genótipo B em outras 2 amostras de I. monticola e G. duodenalis genótipo E em outra amostra de lagarto de Bocage (Podarcis bocagei). Os resultados obtidos, após amplificação e sequenciamento de um fragmento do gene SSU-rDNA, confirmam a presença de G. duodenalis genótipo A em 2 amostras de I. monticola. Esta é a primeira vez que se descreve G. duodenalis em lagartos selvagens, embora sejam necessários outros estudos complementares para confirmar se estes animais sofrem uma infecção real ou se apenas atuam como disseminadores mecânicos da contaminação ambiental. Além disso, a detecção de genótipos zoonóticos e específicos de ruminantes domésticos demonstra a contaminação do ambiente selvagem por G. duodenalis, possivelmente devido à atividade humana.

Componentes alimentarios vegetales y microbianos potencialmente útiles en el tratamiento y control de la giardiasis / Potentially useful in the treatment plant and microbial food components and control of giardiasis

La giardiasis es una infección intestinal de amplia distribución mundial, que presenta manifestaciones clínicas con variaciones desde la infección asintomática, a la enfermedad aguda o crónica asociada con diarrea prolongada y severa y malabsorción de nutrientes. Su agente etiológico es el protozoario Giardia lamblia. La infección se inicia por la ingestión de quistes del parásito, presentes en agua y/o alimentos contaminados o por contacto orofecal directo. Los mecanismos a través de los cuales G. lamblia causa le enfermedad permanecen aún en discusión, pero los principales postulados incluyen tanto alteraciones morfológicas como funcionales de la mucosa intestinal a causa de la adhesión de los trofozoítos a las células epiteliales mediante el disco ventral o suctorio, que afectaría la absorción de nutrientes. El principal tratamiento es la administración de drogas antiparasitarias, muchas de las cuales han demostrado tener un amplio rango de efectos secundarios desagradable, lo cual sumado a la ocurrencia de resultados clínicos insatisfactorios y al surgimiento de cepas resistentes, ha impulsado la búsqueda de nuevas estrategias terapéuticas. Es por ello que el objetivo de esta tesis doctoral fue evaluar la actividad antigiardiásica de componentes alimentarios de origen vegetal y microbiano, como así también la interacción de los mismos con drogas antiparasitarias de uso común.

ABSTRACT: Giardiasis is an intestinal infection of worldwide distribution, presenting with clinical manifestations ranging from asymptomatic infection to acute or chronic disease associated with prolonged and severe diarrhea and malabsorption of nutrients, Its etiologic agent is the protozoan Giardia lamblia. Infection is initiated by ingestion of parasite cysts present in contaminated water and food or by direct fecal-oral contact The mechanisms through which G. lamblia causes disease will remain still under discussion, but the main tenets include both mechanical obstruction as morphological and functional alterations of the intestinal mucosa because of the adherence of trophozoites to epithelial cells by ventral disk that affect nutrient absorption. The main treatment is the administration of antiparasitic drugs, many of which have been shown to have a wide range of unpleasant side effects, which added to the occurrence of unsatisfactory clinical results and the emergence of resistant strains, has prompted the search for new therapeutic strategies.

Cryptosporidium spp., Giardia intestinalis, and Enterocytozoon bieneusi in Captive Non-Human Primates in Qinling Mountains

Non-human primates (NHPs) are confirmed as reservoirs of Cryptosporidium spp., Giardia intestinalis, and Enterocytozoon bieneusi. In this study, 197 fresh fecal samples from 8 NHP species in Qinling Mountains, northwestern China, were collected and examined using multilocus sequence typing (MLST) method. The results showed that 35 (17.8%) samples were positive for tested parasites, including Cryptosporidium spp. (3.0%), G. intestinalis (2.0%), and E. bieneusi (12.7%). Cryptosporidium spp. were detected in 6 fecal samples of Macaca mulatta, and were identified as C. parvum (n=1) and C. andersoni (n=5). Subtyping analysis showed Cryptosporidium spp. belonged to the C. andersoni MLST subtype (A4, A4, A4, and A1) and C. parvum 60 kDa glycoprotein (gp60) subtype IId A15G2R1. G. intestinalis assemblage E was detected in 3 M. mulatta and 1 Saimiri sciureus. Intra-variations were observed at the triose phosphate isomerase (tpi), beta giardin (bg), and glutamate dehydrogenase (gdh) loci, with 3, 1, and 2 new subtypes found in respective locus. E. bieneusi was found in Cercopithecus neglectus (25.0%), Papio hamadrayas (16.7%), M. mulatta (16.3%), S. sciureus (10%), and Rhinopithecus roxellana (9.5%), with 5 ribosomal internal transcribed spacer (ITS) genotypes: 2 known genotypes (D and BEB6) and 3 novel genotypes (MH, XH, and BSH). These findings indicated the presence of zoonotic potential of Cryptosporidium spp. and E. bieneusi in NHPs in Qinling Mountains. This is the first report of C. andersoni in NHPs. The present study provided basic information for control of cryptosporidiosis, giardiasis, and microsporidiosis in human and animals in this area.

Occurrence and Molecular Identification of Giardia duodenalis from Stray Cats in Guangzhou, Southern China

The objective of this study was to genetically characterize isolates of Giardia duodenalis and to determine if zoonotic potential of G. duodenalis could be found in stray cats from urban and suburban environments in Guangzhou, China. Among 102 fresh fecal samples of stray cats, 30 samples were collected in Baiyun district (urban) and 72 in Conghua district (suburban). G. duodenalis specimens were examined using light microscopy, then the positive specimens were subjected to PCR amplification and subsequent sequencing at 4 loci such as glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), beta-giardin (bg), and small subunit ribosomal RNA (18S rRNA) genes. The phylogenetic trees were constructed using obtained sequences by MEGA5.2 software. Results show that 9.8% (10/102) feline fecal samples were found to be positive by microscopy, 10% (3/30) in Baiyun district and 9.7% (7/72) in Conghua district. Among the 10 positive samples, 9 were single infection (8 isolates, assemblage A; 1 isolate, assemblage F) and 1 sample was mixed infection with assemblages A and C. Based on tpi, gdh, and bg genes, all sequences of assemblage A showed complete homology with AI except for 1 isolate (CHC83). These findings not only confirmed the occurrence of G. duodenalis in stray cats, but also showed that zoonotic assemblage A was found for the first time in stray cats living in urban and suburban environments in China.

Occurrence and Molecular Identification of Giardia duodenalis from Stray Cats in Guangzhou, Southern China

The objective of this study was to genetically characterize isolates of Giardia duodenalis and to determine if zoonotic potential of G. duodenalis could be found in stray cats from urban and suburban environments in Guangzhou, China. Among 102 fresh fecal samples of stray cats, 30 samples were collected in Baiyun district (urban) and 72 in Conghua district (suburban). G. duodenalis specimens were examined using light microscopy, then the positive specimens were subjected to PCR amplification and subsequent sequencing at 4 loci such as glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), beta-giardin (bg), and small subunit ribosomal RNA (18S rRNA) genes. The phylogenetic trees were constructed using obtained sequences by MEGA5.2 software. Results show that 9.8% (10/102) feline fecal samples were found to be positive by microscopy, 10% (3/30) in Baiyun district and 9.7% (7/72) in Conghua district. Among the 10 positive samples, 9 were single infection (8 isolates, assemblage A; 1 isolate, assemblage F) and 1 sample was mixed infection with assemblages A and C. Based on tpi, gdh, and bg genes, all sequences of assemblage A showed complete homology with AI except for 1 isolate (CHC83). These findings not only confirmed the occurrence of G. duodenalis in stray cats, but also showed that zoonotic assemblage A was found for the first time in stray cats living in urban and suburban environments in China.

Intestinal parasites and genotyping of Giardia duodenalis in children: first report of genotype B in isolates from human clinical samples in Mexico

Giardia duodenalis is one of the most prevalent enteroparasites in children. This parasite produces several clinical manifestations. The aim of this study was to determine the prevalence of genotypes of G. duodenalis causing infection in a region of southeastern Mexico. G. duodenalis cysts were isolated (33/429) from stool samples of children and molecular genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, targeting the triosephosphate isomerase ( tpi ) and glutamate dehydrogenase ( gdh ) genes. The tpi gene was amplified in all of the cyst samples, either for assemblage A (27 samples) or assemblage B (6 samples). RFLP analysis classified the 27 tpi -A amplicons in assemblage A, subgenotype I. Samples classified as assemblage B were further analysed using PCR-RFLP of the gdh gene and identified as assemblage B, subgenotype III. To our knowledge, this is the first report of assemblage B of G. duodenalis in human clinical samples from Mexico.

Genotipos de Giardia duodenalis en muestras de niños de las guarderías del Instituto Colombiano de Bienestar Familiar y de perros en Ibagué, Colombia / Giardia duodenalis genotypes found in the Instituto Colombiano de Bienestar Familiar day care centers and dogs in Ibagué, Colombia

Introducción. Se han descrito ocho genotipos de Giardia duodenalis, del A al H. Los genotipos A y B se han aislado de humanos y de una gran variedad de mamíferos; sin embargo, los genotipos del C al H han mostrado mayor especificidad de huésped. Objetivo. Identificar los genotipos de G. duodenalis a partir de quistes obtenidos en heces de niños de las guarderías del Instituto Colombiano de Bienestar Familiar (ICBF) y de perros en Ibagué, mediante PCR-RFLP de los genes de la beta giardina y la glutamato deshidrogenasa. Materiales y métodos. Los quistes de las muestras positivas para G. duodenalis fueron sometidos a concentración; se extrajo su ADN y se efectuó el análisis de PCR-RFLP de los genes de la beta giardina y de la glutamato deshidrogenasa. Como control positivo se utilizó la cepa MHOM/CO/04/G40 procedente del Grupo de Parasitología del Instituto Nacional de Salud. Resultados. De las muestras tomadas de niños, 11/23 (48 %) correspondieron al genotipo A y, 12/23 (52 %), al genotipo B. Cuatro muestras de perros presentaron los genotipos C y D, específicos de este huésped. Conclusiones. En los niños solamente se encontraron los genotipos asociados a infecciones humanas (AII, BIII y BIV) y en los perros, los genotipos específicos para este huésped (C y D). Debido al reducido tamaño de las muestras analizadas provenientes de perros, y dado que estos no estuvieron en contacto con los niños de las guarderías del ICBF, no fue posible determinar una interacción entre el ciclo de transmisión de los humanos y el de los animales.

Introduction: Eight Giardia duodenalis genotypes (A-H) have been described to date. Genotypes A and B have been isolated from humans and a wide range of mammals; however, genotypes C-H have shown greater host specificity. Objective: Identifying G. duodenalis genotypes from cysts in faeces obtained from children attending the Instituto Colombiano de Bienestar Familiar (ICBF) day care centres and from dogs in Ibagué by PCR-RFLP targeting both the b -giardin and glutamate dehydrogenase genes. Materials and methods: Cysts from G. duodenalis positive samples were concentrated, DNA was extracted and the b -giardin and glutamate dehydrogenase genes were analysed by PCR-RFLP. The MHOM/CO/04/G40 strain was used as positive control (this was obtained from the Grupo de Parasitología at the Instituto Nacional de Salud ). Results: Of the total human samples, 11/23 (48%) were genotyped as A and 12/23 (52%) as B; PCR-RFLP revealed that four canine samples were genotypes C and D, these being host-specific. Conclusions: Only genotypes associated with human infection (AII, BIII and BIV) were found in the children and host-specific genotypes were observed in canines (C and D). No interaction could be established between animal and human transmission cycles due to the small canine sample size and as the former did not come into contact with children attending ICBF day-care centres.

MOLECULAR TYPING OF Giardia duodenalis ISOLATES FROM NONHUMAN PRIMATES HOUSED IN A BRAZILIAN ZOO / Genotipagem de isolados de Giardia duodenalis de primatas não humanos mantidos em zoológico do Brasil

Giardia infections in captive nonhuman primates (NHP) housed at a Brazilian zoo were investigated in order to address their zoonotic potential. Fresh fecal samples were collected from the floors of 22 enclosures where 47 primates of 18 different species were housed. The diagnosis of intestinal parasites after concentration by sedimentation and flotation methods revealed the following parasites and their frequencies: Giardia (18%); Entamoeba spp. (18%); Endolimax nana (4.5%); Iodamoeba spp. (4.5%); Oxyurid (4.5%) and Strongylid (4.5%). Genomic DNA extracted from all samples was processed by PCR methods in order to amplify fragments of gdh and tpi genes of Giardia. Amplicons were obtained from samples of Ateles belzebuth, Alouatta caraya, Alouatta fusca and Alouatta seniculus. Clear sequences were only obtained for the isolates from Ateles belzebuth (BA1), Alouatta fusca (BA2) and Alouatta caraya (BA3). According to the phenetic analyses of these sequences, all were classified as assemblage A. For the tpi gene, all three isolates were grouped into sub-assemblage AII (BA1, BA2 and BA3) whereas for the gdh gene, only BA3 was sub-assemblage AII, and the BA1 and BA2 were sub-assemblage AI. Considering the zoonotic potential of the assemblage A, and that the animals of the present study show no clinical signs of infection, the data obtained here stresses that regular coproparasitological surveys are necessary to implement preventive measures and safeguard the health of the captive animals, of their caretakers and of people visiting the zoological gardens.

A pesquisa de infecções por Giardia e a caracterização genotípica deste protozoário foi realizada em primatas não humanos (PNH) mantidos em Zoológico a fim de avaliar o seu potencial zoonótico. As amostras dos animais consistiram de fezes colhidas do piso de 22 baias onde eram mantidos 47 primatas de 18 diferentes espécies. Exames coproparasitológicos foram realizados pelos métodos de concentração por sedimentação e centrífugo-flutuação e revelaram a presença dos seguintes parasitas e suas respectivas frequências: Giardia (18%); Entamoeba spp. (18%); Endolimax nana (4.5%); Iodamoeba spp. (4.5%); oxiurídeos (4.5%) e estrongilídeos (4.5%). O DNA extraído de todas as amostras fecais foi submetido à técnica de PCR para a amplificação dos genes gdh e tpi de Giardia, porém, só foram obtidos amplicons das quatro amostras positivas provenientes de Ateles belzebuth, Alouatta caraya, Alouatta fusca and Alouatta seniculus. O seqüenciamento dos fragmentos amplificados foi possível apenas para as amostras oriundas de Ateles belzebuth (BA1), Alouatta fusca (BA2) e Alouatta caraya (BA3), cuja análise fenética de ambos os genes revelou pertencerem ao genótipo A. As análises das sequências de tpi revelaram que todas as amostras pertencem ao subgenótipo AII. No que se refere ao gene gdh as análises revelaram uma amostra pertencente ao subgenótipo AII (BA3) e duas ao subgenótipo A1 (BA1 e BA2). Considerando o potencial zoonótico do genótipo A e o fato de que os animais não apresentavam sintomas de infecção, os dados do presente trabalho salientam a importância de se realizar, periodicamente, exames coproparasitológicos dos animais de zoológico, para implementação de medidas preventivas para resguardar a saúde dos animais em cativeiro, a de seus tratadores e dos visitantes de parques zoológicos.

Genotyping of Giardia duodenalis Isolates from Dogs in Guangdong, China Based on Multi-Locus Sequence

This study aimed to identify the assemblages (or subassemblages) of Giardia duodenalis by using normal or nested PCR based on 4 genetic loci: glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), beta-giardin (bg), and small subunit ribosomal DNA (18S rRNA) genes. For this work, a total of 216 dogs' fecal samples were collected in Guangdong, China. The phylogenetic trees were constructed with MEGA5.2 by using the neighbor-joining method. Results showed that 9.7% (21/216) samples were found to be positive; moreover, 10 samples were single infection (7 isolates assemblage A, 2 isolates assemblage C, and 1 isolate assemblage D) and 11 samples were mixed infections where assemblage A was predominant, which was potentially zoonotic. These findings showed that most of the dogs in Guangdong were infected or mixed-infected with assemblage A, and multi-locus sequence typing could be the best selection for the genotype analysis of dog-derived Giardia isolates.

Identification of an immunogenic protein of Giardia lamblia using monoclonal antibodies generated from infected mice

The humoral immune response plays an important role in the clearance of Giardia lamblia. However, our knowledge about the specific antigens of G. lamblia that induce a protective immune response is limited. The purpose of this study was to identify and characterise the immunogenic proteins of G. lamblia in a mouse model. We generated monoclonal antibodies (moAbs) specific to G. lamblia (1B10, 2C9.D11, 3C10.E5, 3D10, 5G8.B5, 5F4, 4C7, 3C5 and 3C6) by fusing splenocytes derived from infected mice. Most of these moAbs recognised a band of ± 71 kDa (5G8 protein) and this protein was also recognised by serum from the infected mice. We found that the moAbs recognised conformational epitopes of the 5G8 protein and that this antigen is expressed on the cell surface and inside trophozoites. Additionally, antibodies specific to the 5G8 protein induced strong agglutination (> 70-90%) of trophozoites. We have thus identified a highly immunogenic antigen of G. lamblia that is recognised by the immune system of infected mice. In summary, this study describes the identification and partial characterisation of an immunogenic protein of G. lamblia. Additionally, we generated a panel of moAbs specific for this protein that will be useful for the biochemical and immunological characterisation of this immunologically interesting Giardia molecule.

Molecular identification of Giardia duodenalis in Ecuador by polymerase chain reaction-restriction fragment length polymorphism

The aim of this study was to determine the genetic diversity of Giardia duodenalis present in a human population living in a northern Ecuadorian rain forest. All Giardia positive samples (based on an ELISA assay) were analysed using a semi-nested polymerase chain reaction-restriction fragment length polymorphism assay that targets the glutamate dehydrogenase (gdh) gene; those amplified were subsequently genotyped using NlaIV and RsaI enzymes. The gdh gene was successfully amplified in 74 of 154 ELISA positive samples; 69 of the 74 samples were subsequently genotyped. Of these 69 samples, 42 (61%) were classified as assemblage B (26 as BIII and 16 as BIV), 22 (32%) as assemblage A (3 as AI and 19 as AII) and five (7%) as mixed AII and BIII types. In this study site we observe similar diversity in genotypes to other regions in Latin America, though in contrast to some previous studies, we found similar levels of diarrheal symptoms in those individuals infected with assemblage B compared with those infected with assemblage A.

Muerte celular programada en protozoarios: el caso de Giardia intestinalis / Programmed cell death in protozoa: Giardia intestinalis’s case

Giardia intestinalis es considerado uno de los eucariotas más antiguos y su poca complejidad representa una valiosa oportunidad para desentrañar los misterios de procesos vitales de eucariotas más complejos. Esta característica única de G. intestinalis y el hecho de que su genoma esté completamente secuenciado y disponible, y que todo su ciclo de vida puede ser reproducido in vitro, hacen de este parásito un modelo ideal para estudiar mecanismos celulares, entre ellos, la muerte celular programada. Desde el punto de vista morfológico y molecular, la apoptosis es uno de los tipos más complejos de muerte celular programada, la cual es un proceso normal durante el desarrollo celular, y tiene un papel esencial en el control de la proliferación celular y en la respuesta a retos inmunológicos o a daños celulares. Recientemente, se ha reportado que en protozoos, entre ellos Giardia, podría ocurrir un tipo de muerte celular programada similar a la apoptosis y los resultados de nuestros laboratorios apoyan esta hipótesis; sin embargo, no se han identificado hasta el momento las moléculas relacionadas con los procesos de apoptosis en estos parásitos. La presente revisión abarca una descripción de la morfología y estructura de las formas de vida de G. intestinalis, de su ciclo biológico, de la parasitosis que causa y de las estrategias quimioterapéuticas para su tratamiento. Asimismo, se hace un repaso de lo que hasta ahora se conoce sobre apoptosis en protozoarios, y específicamente en G. intestinalis, y se describen algunos resultados de nuestro grupo que apoyan la existencia de muerte celular programada en este parásito.

Giardia intestinalis is an early-branching eukaryote and its low complexity represents a valuable opportunity to unravel the mysteries of essential processes in more complex eukaryotes. In addition, the genome of G. intestinalis is completely sequenced and its entire life cycle can be reproduced in vitro. All these characteristics make of Giardia an ideal model for studying cellular mechanisms, such as programmed cell death. Apoptosis is one of the most complex types of programmed cell death and plays an essential role during cell development, cell proliferation and immune response. Recently it has been reported that in Giardia can take place events that resemble apoptosis and although our results support this hypothesis, molecules involved in this process have not yet been identified. This review includes a description of the morphology and structure of G. intestinalis, its life cycle, the disease that causes and the strategies for its treatment. In addition, we review what is known about apoptosis in protozoa, and specifically in G. intestinalis, and describe some results from our group supporting the existence of apoptosis-like programmed cell death in this parasite.

Giardia duodenalis: genotypic comparison between a human and a canine isolates / Giardia duodenalis: comparação genotípica entre isolados humano e canino

INTRODUCTION: Evidence suggests that giardiasis is a zoonotic disease. The present work aimed to evaluate the genetic identity of Giardia duodenalis isolated from human and dog fecal samples from Belo Horizonte. METHODS: Human and dog fecal samples were cultured for isolation of G. duodenalis. To determine the genotype of the isolates, primers that amplify a specific region in rRNA of the protozoan were used. RESULTS: Two G. duodenalis isolates were obtained, which belong to the subgroup A genotype. CONCLUSIONS: These findings suggest that the transmission of giardiasis follows a zoonotic pattern.

INTRODUÇÃO: Evidências sugerem que a giardíase é uma doença zoonótica. O presente trabalho tem como objetivo avaliar a identidade genética da Giardia duodenalis isolada de fezes humanas e de cães de Belo Horizonte. MÉTODOS: Amostras de fezes humanas e de cães foram cultivadas para isolamento de G. duodenalis. Para determinação do genótipo dos isolados, foram usados oligonuclotídeos que amplificam regiões específicas do gene para rRNA. RESULTADOS: Dois isolados de G. duodenalis foram obtidos, os quais apresentaram o genótipo do sub-grupo A. CONCLUSÕES: Estes dados sugerem que a transmissão da giardíase segue um padrão zoonótico.

Prevalence of Cryptosporidium spp. and Giardia spp., spatial clustering and patterns of shedding in dairy calves from Córdoba, Argentina / Prevalência de Cryptosporidium spp. e Giardia spp., distribuição espacial e padrões de eliminação em bezerros de propriedades leiteiras em Córdoba, Argentina

The objectives of this study were to estimate calf and herd prevalence of Cryptosporidium spp. and Giardia spp., the herd prevalence clustering, spatial distribution according to soil type and shedding patterns in dairy calves from Cordoba, Argentina. Six hundred twenty calves younger than 7 weeks of age from 43 dairy herds were sampled. Samples were processed with the formol-ether and modified Ziehl-Neelsen techniques. Univariate analysis and Kruskall-Wallis tests were used. Factors associated were subjected to multivariate analysis with calf shedding intensity as the response variable. Clustering of herd prevalence was assessed by a scan method, and spatial analysis was applied to explore the overlapping of high prevalence herds and soil type. Overall calf prevalence for Cryptosporidium spp. oocysts and Giardia spp. cysts were 19.35 percent (95 percent CI: 16.14; 22.54) and 34.50 percent (95 percent CI: 30.69; 38.34), respectively. Calves younger than two weeks of age were almost four times more likely to be infected with Cryptosporidium, in comparison to older ones (RR: 3.78, 95 percent CI: 2.27; 6.26). Giardia spp. shedding showed a similar age pattern (RR: 1.33, 95 percent CI: 1.02; 1.75). A primary cluster of high Cryptosporidium prevalence was found, and high prevalence herds were located in areas with poor drained soil.

Os objetivos deste estudo foram determinar a prevalência de Cryptosporidium spp. e Giardia spp., a presença de aglomerados, a distribuição espacial de acordo com o tipo de solo e padrões de eliminação de cistos e oocistos em bezerros de propriedades leiteiras em Córdoba, Argentina. Amostras fecais foram colhidas de 620 bezerros com menos de sete semanas de idade, provenientes de 43 propriedades leiteiras e examinadas pelas técnicas de formol-éter e Ziehl-Neelsen modificada. Foram realizadas uma análise univariada e o teste de Kruskal-Wallis e, em seguida, uma análise multivariada com a intensidade de eliminação de cistos e oocistos, como um evento. A presença de aglomerados foi determinada com o método de varredura e a análise espacial foi realizada para explorar a sobreposição de rebanhos com alta prevalência e tipo de solo. A prevalência de Cryptosporidium spp. e Giardia spp. foi de 19,35 por cento (IC 95 por cento: 16,14; 22,54) e 34,50 por cento (IC 95 por cento: 30,69; 38,34), respectivamente. A probabilidade de infecção por Cryptosporidium spp. foi quase quatro vezes maior para bezerros com menos de 2 semanas em comparação com os bezerros mais velhos (RR: 3,78, IC 95 por cento 2,27; 6,26). O mesmo padrão de infecção relacionada à idade foi observado para Giardia spp. (RR: 1,33, IC 95 por cento 1,02; 1,75). Foi encontrado um aglomerado primário com alta prevalência de Cryptosporidium spp., e rebanhos com alta prevalência foram localizados em solos mal drenados.

The effects of nitric oxide on the immune response during giardiasis

Nitric oxide (NO) is a free radical synthesized from L-arginine by different isoforms NO-synthases. NO possesses multiple and complex biological functions. NO is an important mediator of homeostasis, and changes in its generation or actions can contribute or not to pathological states. The knowledge of effects of NO has been not only important to our understanding of immune response, but also to new tools for research and treatment of various diseases. Knowing the importance of NO as inflammatory mediator in diverse infectious diseases, we decided to develop a revision that shows the participation/effect of this mediator in immune response induced against Giardia spp. Several studies already demonstrated the participation of NO with microbicidal and microbiostatic activity in giardiasis. On the other hand, some works report that Giardia spp. inhibit NO production by consuming the intermediate metabolite arginine. In fact, studies in vitro showed that G. lamblia infection of human intestinal epithelial cells had reduced NO production. This occurs due to limited offer of the crucial substrate arginine (essential aminoacid for NO production), consequently reducing NO production. Therefore, the balance between giardial arginine consumption and epithelial NO production could contribute to the variability of the duration and severity of infections by this ubiquitous parasite.

Giardíase: aspectos gerais / Giardiasis: general aspects

A parasitose por Giardia intestinalis é de distribuição mundial. Sua prevalência no Brasil é alta em algumas regiões, principalmente naquelas onde o saneamento básico e as medidas higiênicas são precários. Acomete com mais frequência crianças de zero a seis anos. Geralmente é uma parasitose sem intercorrências graves, mas cabe maior atenção quando acomete pessoas com desnutrição, fibrose cística ou algumas imunodeficiências. O diagnóstico clínico é impreciso, sendo, então, necessários os métodos laboratoriais. O tratamento é simples e eficaz. Embora a Giardia intestinalis seja extremamente infecciosa, a doença pode ser prevenida. O objetivo deste artigo é discorrer sobre os principais aspectos da giardíase.

Manifestaciones cutáneas de la giardiasis, sobredimensión de un problema de salud / Cutaneous manifestations of giardiasis - an overdimensioned health problem

Objetivo: caracterizar desde el punto de vista clínico y parasitológico a un grupo de pacientes que en la red de salud de Ciudad de La Habana habían sido tratados, o serían tratados, por padecer de manifestaciones cutáneas atribuidas a giardiasis. Métodos: previo acuerdo con los médicos de asistencia correspondientes, 114 individuos que habían sido tratados, o serían tratados, por padecer de lesiones dermatológicas atribuidas a giardiasis fueron remitidos al Instituto de Medicina Tropical Pedro Kourí (IPK). A su arribo, a cada paciente se le realizó una caracterización de sus manifestaciones clínicas por parte de los médicos que formaban parte del equipo de investigadores. A cada individuo se le solicitó muestras seriadas de heces, a las que se le practicaron exámenes cropológicos mediante los procedimientos de frotis directo simple y de concentración de Ritchie. En aquellos casos en que la observación microscópica de las muestras de heces no permitió confirmar la infección por Giardia lamblia, se realizó drenaje biliar para la búsqueda microscópica de las giardias en el líquido duodenal correspondiente. A los pacientes en cuyas heces o líquido duodenal se detectó la presencia de G. lamblia, se les indicó tratamiento antigiardiásico y se orientaron las medidas higiénico-sanitarias necesarias para evitar la reinfección. Después de 3 meses de concluido el tratamiento antiparasitario, se repitieron los estudios antes descritos. Resultados: se demostró que en Ciudad de La Habana las manifestaciones cutáneas de la giardiasis constituyen un problema de salud sobredimensionado. Se confirmó, además, que son las lesiones urticarianas las manifestaciones dermatológicas más frecuentes asociadas a giardiasis. Conclusiones: demostrada la sobredimensión de la giardiasis como causa de lesiones dermatológicas, se hace necesario incursionar en la exploración de los conocimientos, percepciones...

Objective: to make a clinical and parasitological characterization of a group of patients, who had been or would be treated in the healthcare facilities of the City of Havana, due to their cutaneous manifestations attributed to giardiasis. Methods: after the consent of their primary care physicians, 114 subjects, who had been or would be treated because of their giardiasis-attributed skin lesions, were referred to Pedro Kourí Institute of Tropical Medicine. On their arrival, the research team physicians characterized each patient according to their clinical manifestations. They were asked to collect their feces for serial sampling, which were subjected to chropological tests through direct simple smears and Ritchie´s concentration procedures. In those cases where microscopic observation of samples did not allow confirming Giardia lamblia infection, biliary drainage was performed to look for giardias in the corresponding duodenal fluid. The patients whose feces or duodenal fluid showed G.lamblia were instructed to follow an anti-giardiasis treatment and the necessary hygienic-sanitary measures to prevent re-infection. Three months after concluding the parasiticidal treatment, the above-mentioned tests were repeated. Results: it was proved that the cutaneous manifestations of giardiasis in the City of Havana are an overdimensioned health problem. It was also confirmed that urticaria is the most frequent giardiasis-associated dermatological manifestation. Conclusions: once the overdimension of giardiasis as a cause of skin lesions is proven, it is necessary to explore the knowledge, perceptions and practice of physicians in charge of diagnosis, treatment and control of this disease.