Parasitosis y síndrome de intestino irritable / Parasitosis and irritable bowel syndrome

El síndrome de intestino irritable (SII) es un trastorno funcional digestivo de etiología multifactorial. En su fisiopatología se describen diversos factores, tanto biológicos, como psicológicos y ambientales, que afectan el estado de activación de células inmunes en la mucosa intestinal. Entre los factores ambientales se incluye la presencia de alguna parasitosis intestinal. El síndrome de intestino irritable post-infeccioso (SII-PI) es reconocido como un subgrupo de estos trastornos, cuya aparición de los síntomas es posterior a una infección intestinal provocada por agentes microbianos. A pesar de que en Chile hay pocos estudios respecto a la relación entre SII y parasitosis intestinal, se ha descrito la existencia de una asociación positiva entre SII e infecciones por Blastocistis hominis, uno de los parásitos prevalentes en Chile. En otros países, se ha descrito además una relación entre SII, amebiasis y giardiasis. Por la alta prevalencia de parasitosis en nuestro país, existe la necesidad de ampliar los estudios para clarificar la fuerza de la asociación entre parasitosis y SII.

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract characterised by multi-factorial aetiology. In IBS physiopathology are involved diverse factors between them biological, psychosocial, and environmental components which affect the immune activation status of gut mucosa. Among these factors is recognized the intestinal parasitosis. Post-infection IBS (PI-IBS) is recognised as a subgroup of functional disorders whose symptoms onset appear after a symptomatic intestinal infection caused by microbial agents. There are few studies regarding of relationship between IBS and intestinal parasitosis in Chile. However, is has been well described a positive association between IBS and Blastocystis hominis infections, one of prevalent parasites in Chile. In other countries, is also described a relationship between IBS and amebiasis and giardiasis. Both, characterized by a common mode of transmission through water as well as contaminated food. Because the high prevalence of parasitosis in our country it is necessary to expand the association studies to clarify the strength of the parasites ethiology in IBS.

Prevalence and seasonal variation of human intestinal parasites in patients attending hospital with abdominal symptoms in northern Jordan

This study was carried out to determine the prevalence of intestinal parasites and their seasonal variation in northern Jordan. A total of 21 906 stool samples were collected over a period of 4 years [2009-2013] from 5 government hospitals in 3 cities. Samples were processed and examined microscopically and by concentration methods. Parasitic infection was found in 9611 samples [44%]. Giardia lamblia was the most prevalent parasite [41%] followed by Entamoeba histolytica [31%] and Ent. coli [13%]; the least prevalent parasites were Ascaris lumbricoides [1%], Hymenolepis nana, Taenia sp., and Chilomastix mesnili [all < 1%]. The prevalence of different parasites varied according to season, on average the summer months showed the highest incidence of parasitic infection [62%] compared with the winter months [16%]. Giardia lamblia and Ent. histolytica were most prevalent in the summer months

Atualidades sobre giardíase / Updates on giardiasis

A giardíase é uma parasitose intestinal amplamente distribuída pelo mundo, com alta prevalência em países em desenvolvimento, inclusive o Brasil. Embora seja uma infecção com bom prognóstico, pode apresentar gravidade em pessoas com desnutrição, fibrose cística ou algumas imunodeficiências. Este artigo tem como objetivo atualizar os principais aspectos da giardíase.

Giardiasis is an intestinal parasite widely distributed around the globe with high prevalence in developing countries, including Brazil. Although it is an infection with a good prognosis may present serious in people with malnutrition, cystic fibrosis or certain immunodeficiencies. The aim of this paper is to perform an update on key aspects of giardiasis.

Mecanismos específicos de patogenicidadede protozoários de mucosa: Entamoeba histolytica, Giardia lamblia e Trichomonas vaginali / Specific pathogenic mechanisms of mucosal protozoans: Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis

Entamoeba histolytica e Giardia lamblia são protozoários que podem parasitar a mucosa intestinal, causando principalmente diarreia. Trichomonas vaginalis coloniza a mucosa vaginal causando tricomonose, a doença sexualmente transmissível não viral mais comum no mundo. Embora coletivamente estes parasitos infectem mais de um bilhão de pessoas a cada ano, seus mecanismos de patogenicidade ainda não estão totalmente esclarecidos. Assim, esta revisão reúne os principais mecanismos envolvidos na patogenicidade destes protozoários, bem como os fatores do microambiente que podem interferir no sucesso da colonização. A patogênese da E. histolytica envolve adesão, lise, fagocitose de células epiteliais e bactérias, invasão tecidual por ação de enzimas e evasão da resposta imune do hospedeiro. A lectina Gal/GalNAc, os amebaporos e as cisteína proteases são as principais moléculas envolvidas nesses processos. O estabelecimento da giardiose depende de diversos mecanismos patogênicos e de virulência desenvolvidos pela G. lamblia, tais como as moléculas envolvidas na adesão, encistamento e variação antigênica. Para o sucesso da colonização da mucosa vaginal, o T. vaginalis expressa moléculas como as adesinas de superfície, lipofosfoglicanos e galectina, envolvidas na adesão às células epiteliais vaginais e alteração da expressão gênica, tanto do parasito como do hospedeiro.

Entamoeba histolytica and Giardia lamblia are protozoans that may parasitize the intestinal mucosa, mainly causing diarrhea. Trichomonas vaginalis colonizes the vaginal mucosa causing trichomonosis, the most common non-viral sexually transmitted disease in the world. Although collectively these parasites infect over a billion people each year, their pathogenic mechanisms have not been completely understood so far. Hence, this review of the literature demonstrates the main mechanisms involved in the pathogenicity of these protozoans, as well as the microenvironmental factors that can interfere with successful colonization. The pathogenesis of E. histolytica involves adhesion, lysis, phagocytosis of epithelial cells and bacteria, tissue invasion by enzymatic action, and evasion of host immune response. Lectin Gal/GalNac, amoebapores, and cysteine proteases are the main molecules involved in these processes. The establishment of giardiosis depends on several pathogenic mechanisms and virulence developed by G. lamblia, such as molecules involved in adhesion, encystation and antigenic variation. For successful colonization of vaginal mucosa, T. vaginalis express molecules like adhesins on the surface and galectin and lipophosphoglycan, involved in the adherence to vaginal epithelial cells and altered gene expression of both the parasite and the host.

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.

Epidemiología: [revisión] / Epidemiology: [review]

Las enfermedades diarreícas, constituyen un problema mundial, con altas tasas de morbilidad y mortalidad, especialmente en países en vías de desarrollo. Venezuela presentó, en el año 2008, 1.768.509 casos de diarrea, con un 40 por ciento en menores de 5 años. El total de muertes en menores de 5 años en el período 2000-2007 fue de 9311, siendo la tercera causa en este grupo de edad. Entre las bacterias, el género Salmonella, es el más frecuentemente aislado en brotes epidémicos. En niños menores de 6 años. E.coli enteropatógena fue el agente principal, seguido por E.coli enteroinvasiva, Aeromonas sp., salmonella sp y Shigella. Campylobacter es una de las bacterias más frecuentemente en las heces de los lactantes y niños en países en desarrollo. En algunos países, tener en cuenta al Vibrium Cholera y en diarreas nosocomiales al Clostridium difficile. En lactantes y preescolares la etiología viral es la más frecuente y el rotavirus el agente más común, causando aproximadamente 15000 muertes anuales en la región de las Américas. Otros virus causantes de diarreas , son los calicivirus y los adenovirus. Los factores de riesgo están relacionados con el medio ambiente, estilos de vida, factores dependientes de la biología humana y de los sistemas de servicios de salud. Las medidas de prevención y control epidemiológico más importantes son la promoción de la lactancia materna, hábitos adecuados de higiene y saneamiento ambiental, uso adecuado de antibióticos, terapia de rehabilitación oral e intravenosa, inmunizaciones, mejoría de las condiciones socio sanitarias y sistemas eficientes de vigilancia epidemiológica.

Diarrheal diseases constitute a global problem, with high rates of morbidity and mortality, particulary in developing countries. Venezuela, for 2008, presented 1.768.509 cases of diarrhea, with 40% in children under 5 years. The total number of dealths in children under years of age in the period 2000-2007 was 9311, being the third learding cause in this age group. Among causing bacterias, Salmonella in the most isolated in outbreaks. In children under 6 years, E.Coli was the principal agent, followed by E.coli., enteroinvasive, Aeromonas sp., Salmonella sp, and Shigella. Campylobacter is one of the most common bacterial in the feces of infants and children in developing countries. In some countries, Vibrium Cholera and Clostridium difficile should be considered. In infants and preshool children, viral etiology is the most frequent and rotavirus the most common agent, causing about 15000 deaths annually in the region of the Americas. Other viruses that cause diarrhea are the calciviruses and adenoviruses. Risk factors are related to the environment, lifestyles, factors dependent on human biology and health care systems. The most important prevention and control measures are the promotion of breastfeeding, proper habits of hygiene and sanitation, proper use of antibiotics, oral and intravenous rehydration therapies, immunization, improvement of sanitary conditions and efficient surveillance systems.

Citocinas séricas en niños infectados con giardia lamblia / Serum citokines in children infected with giardia lamblia

La giardiasis instetinal es un problema de salud pública en los países en desarrollo. Aunque los mecanismos de inmunidad innata y adquirida son necesarios para el control de la infección, son escasos los estudios sobre la participación de las citocinas Th1 y Th2 en el control de la infección en humanos. Determinar en niños infectados con Giardia lamblia (G.lamblia) las concentraciones séricas de las citocinas Th1 (IL-2 e IFN-gamma) y Th2 (IL-4 e IL-10). Se seleccionaron 101 niños (3-6 años; F=52, M=49) nutricionalmente eutróficos; 62 años no parasitados y 39 años con trofozoitos y/o quistes de G.lamblia según estudio coproparasitológico. Las concentraciones séricas de IFN-gamma, IL-4 e IL-10 (pg/mL) fueron determinadas por el método ELISA y la IL-2 (U/mL) por el método EAISA. Para comparar las medias de los grupos se utilizó la prueba t de Student. Se consideró el 95 por ciento de confiabilidad estadística (p<0.05). Nuestros resultados no evidenciaron diferencias estadísticamente significativas entre los valores séricos de las citocinas analizadas entre los niños no infectados y los infectados con G.lamblia. Las proteínas antigénicas específicas de G.lamblia son pobres inmunógenos, por lo cual no son capaces de estimular las células linfoides para la producción de citocinas en suero, para ello son necesarios otros estudios in vivo e in vitro que permitan la caracterización del patrón de citocina Th1 y/o Th2, como uno de los elementos necesarios para el control de la infección.

Intestinal giardiasis is a public health problem in developing countries. Although the innate and adaptative immunity mechanisms are necessary for proper control of the infection, few studies have been published in humans on the role of cytokine Th1-Th2 in infection control. The aim of the present study was to analyze the serum concentration of Th1 cytokine (IL-2 and IFN-gamma) and Th2 (IL-4 and IL-10) in euthrophic children infected or not with Giardia lamblia (G.lamblia). Were analyzed 101 children (3-6y; F=52, M=49) nutritionally eutrophic. Sixty two children free of G.lamblia and 39 infected.The serum concentration of IFN-gamma, IL-4 and IL-10 (pg/mL) were determined by ELISA method and IL-2 (U/mL) by EAISA method. The Student’s t test was applied to compare the groups. We considered 95% statistical significance (p<0.05). Cytokine values in children infected with G.lamblia were not statistically different from values in not infected children, probably due to the labile capacity of antigenic proteins to stimulate the immune response. Other in vivo and in vitro studies are necessary to detect the role of cytokine Th1-Th2 in infection control.

Effect of giardia lamblia Infection on the cognitive function of school children

The association between helminthic parasitic infection and cognitive function has long been recognized, however there are few reports about Giardia lamblia infection. This paper describes a study about the effect of G. lamblia infection on the cognitive function. One hundred thirty two children infected with G. lamblia from Robat Karim south of western Tehran, Iran were compared with 150 children without any parasitic infection. These two groups were identical in socioeconomic and nutritional status. Cognitive function was assessed using, three tests from Wechsler Intelligence Scale for children and one subset of the Clinical Evolution of Language Function. Comparison of two groups revealed that uninfected children improved significantly more than children who had G. lamblia infection in the tests of Fluency [P< 0.02] and Digit-span Forwards/ Backwards [P< 0.004]. Regular stool examination is suggested in areas with low hygienic conditions, since G. lamblia infection might be present without any clinical manifestation

Nutritional status of preschool children infected with giardia intestinalis

Giardia intestinalis is the most common intestinal parasite in human worldwide. It can produce a wide spectrum of clinical manifestations. In order to assess the nutritional status of preschool children infected with Giardia intestinalis, a cross sectional study was made in Marvdasht city, Fars Province, Southern Iran. A total of 337 preschool boys and girls aged 3-6 years were randomly selected for stool examination of intestinal parasites as well as measurement of height, weight, head and arm circumferences. A total of 77 individuals were infected with G. intestinalis. Seventy-one individuals who had only G. intestinalis and 229 with no parasitic infections were selected as infected and control groups, respectively. Z-Score of -2SD was used as cut off point of malnutrition. A total of 9 [12.7%] of infected children and 18 [7.9%] of non infected individuals had a height for age Z-score [HAZ] below -2SD. Eight [11.3%] of former group had a weight for age Z-score [WAZ] under-2SD. In control group 4.4% of preschool children had WAZ under-2SD. 4.2% of infected children had a weight for height Z-score [WHZ] under-2SD but none of the controls had it. Statistical analysis showed a significant difference in height, weight, head circumference, HAZ, and WAZ between infected and control children [P<0.05]. Also, HAZ and WAZ, was significantly different between these two groups, but not for WHZ. A higher infection with G. intestinalis in the children with lower parents' education was observed. However the distribution of malnutrition was not significantly different between boys and girls. In conclusion the present study indicated that giardiasis retarded growth of preschool children in this region

Prevalence of giardia lamblia infection in Amman, Jordan

To determine the prevalence rate of giardiasis among adults and children, males and females of various socio-economic levels in the city of Amman, Jordan.Patients and All individuals [510] visiting Primary Health Care Centers [PHCCs], were recruited in the study. For each, stool samples were examined microscopically by the formalin ethyl acetate concentration method, and to study contributing factors, structured questionnaire was filled out. The overall prevalence was 29.6%. For children, adults, females, males was 78%, 19.3%, 57.3%, 22.6% respectively. Socio-economic status was not a significant factor in the prevalence of giardiasis, while age and sex were significant factors. Water, personal hygiene and sanitation are contributing factors in the spread of giardiasis. This study could be of value for health care workers, sanitary engineers and health policy strategies

The hematological status, plasma vitamin B12 and folic acid levels, and intestinal pathology in rats infected with Giardia lamblia.

The purpose of our study was to investigate the hematological status, vitamin B12 and folic acid absorption and intestinal pathology after Giardia lamblia infection in a rat model. Adult Wistar rats were assigned randomly to receive human giardia cysts orally in the amount of 5 x 10(5) or 1.0 x 10(6) cysts, or none in the controls. The results showed that all the rats injected with giardia cysts became infected. The cyst output in the infected rats varied considerably. In rats infected with 5.0 x 10(5) giardia cysts, the incubation period until cyst output was 10 days compared with 4 days in rats infected with the higher amount of 1.0 x 106 giardia cysts. The highest peaks for cysts output in these 2 groups were on days 4-33, which decreased gradually to days 40-58. The hematocrit and hemoglobin levels in the infected rats were statistically significantly lower than in the controls on days 16, 22, 33, and 37 post-infection (p < 0.05). A reverse relationship between giardia cyst output and hemoglobin concentration was found in the infected rats (p = 0.05). There were no significant differences in plasma vitamin B12 and folic acid levels between the infected rats and the control rats. No pathological changes were found in the small intestine of infected rats. These findings suggest that giardiasis did not affect the absorption of plasma vitamin B12 and folic acid but caused anemia in a rat model.

Giardiasis and its relation to anemia and failure to growth in children

Giardiasis is one of the most famous parasitological infections in the humans, the causing factor is the flagellate protozoan Giardia Lamblia which is living in the upper part of the small intestine attaching to the mucousa membrane. The infection with this flagellate may cause diarrhea disease that varies in severity, wherease the chronic infection with this parasite may cause mal absorption and a celiac disease like syndrome which lead specially in children to anemia and retardation in growth and development. Our studying performed on four groups, which contained 465 child. We diagnosed the giardia parasite through fecal microscopic test, and we applied hematological tests and special measurement to diagnose the failure to growth. We found that the percentage of giardiasis is 24%, and the percentage of children with anemia beside giardiasis is 37%, while the percentage of children with failure to growth and giardiasis is 43%, but the percentage of children with anemia and failure to growth and giardiasis is 22%

Hypoproteinaemia and edema due to giardiasis

The present report describes a 5-years-old girl who presented with hypoproteinaemia and generalised oedema due to giardiasis. She recovered fully 2 weeks after treatment with oral metronidazole. The emphasis is on the importance of giardiasis in children with hypoproteinaemia of obscure aetiology

Intestinal parasitic infections in children from Northern Pakistan

Intestinal parasitic infections cause significant morbidity in children of developing countries, where the vicious cycle of infections and malnutrition impairs their physical growth and development. A community based cross-sectional study on randomly selected children under 15 years of age was performed in two towns of Northern Pakistan. Information on hygiene, sanitation, waste disposal, water supply and maternal education was collected and the nutritional status of these children was assessed. Stool samples of the subjects were collected, immediately preserved and later examined for parasites, with severity of infection being quantified. Of the 89 samples examined, 91% contained one or more parasites. The lowest prevalence of infection was in children less than one year old. Majority of those infected in both towns were girls. Fifty-one percent of the infected children from Yasin and 38% from Singal suffered from malnutrition. Maternal education, family income and drinking water treatment did not affect the prevalence of infection in either town. The most frequent parasites isolated were Ascaris lumbricoides [66.3%], Entamoeba histolytica [27%], Blastocystis hominis [27%], Giardia lamblia [24.7%], and Trichuris trichiura [15.7%]. The results of this study indicate that parasitic infections in northern Pakistan have a high prevalence but low intensity. Programs for early detection and interventional strategies, along with improved hygiene, sanitation and waste disposal facilities are urgently needed to improve the health of these children

Giardiasis co-existing with pregnancy: a distressing and threatening condition

To treat or not to treat Giardia lamblia infection during pregnancy is a debatable issue since, at occasions, it may be advisable to withhold antiparasitic therapy till after delivery. There is no justification for a prescription simply because Giardia lamblia was detected on routine stool microscopy. There is convincing evidence that Giardiasis fits into the category of infectious diseases, which become more severe in pregnancy. The increased nutritional requirements, lowered immunological status and decreased gastric acidity may predispose the already existing Giardial infection to symptomatic Giardiasis which may cause intestinal mucosal injury resulting in disruption of the digestive and absorptive capacity of gut. Three cases of pregnancy associated Giardiasis, in a suburban setting in Punjab [Pakistan], are being reported. The severity of the disease in these patients, impending damage to their foetuses- and public health significance necessitated immediate intervention in the form of specific anti-giardial therapy. The choice of the drug was based on the clinical evaluation and obstetric status. The first patient [23 weeks gestation] was given Intravenous Metronidazole and the third one [30 weeks gestation] oral Secnidazole. Paromomycin [very poorly absorbed from gastrointestinal tract] was selected for the second case [11 weeks gestation]. Regular clinical, parasitological and ultrasonic follow ups of the cases, till term, were carried out. They had uneventful deliveries with normal healthy looking babies. Screening for Giardia lamblia in the family contacts of these patients revealed 11[8 children, 3 adults] parasitologically proven cases [linked to the index cases]. They were successfully treated. It was justifiably concluded that treating the pregnant ladies with acute symptomatic Giardiasis and search for index cases in their family contacts [and their management] were very well rewarding

Efectividad del secnidazol en el tratamiento de escolares asintomáticos parasitados por giardia lamblia y/o entamoeba histolytica / Effectiveness of secnidazol in the treatment of asymptomatic schoolchildren parasited by giardia lamblia and/or entamoeba histolytica

El propósito de la investigación es conocer la eficacia del Secnidazol en el tratamiento de escolares asintomáticos portadores de Giardia lamblia y/o Entamoeba histolytica, así como el evaluar su tolerancia. Se escogieron 50 niños parasitados (totalizando 53 casos con Entamoeba histolytica y/o Giardia lamblia), con edades comprendidas entre 5 y 14 años, de uno u otro sexo, a quienes se les administró el medicamento y tres días después se realizaron exámenes coproparasitológicos controles. La tolerancia del medicamento se evaluó mediante encuesta. De 53 casos parasitados, la relación de protozoarios fue: Giardia lamblia (66,03 por ciento) seguidos de Entamoeba hitolytica (33,97 por ciento). La efectividad parasitológica del Secnidazol contra Giardia lamblia fue del 100 por ciento y de Entamoeba histolytica de 95,45 por ciento. Se obtuvo un solo caso portador que no respondió al tratamiento (4,55 por ciento). El medicamento fue bien tolerado en el 50 por ciento de los casos. Los síntomas más frecuentes fueron: hiporexia, cefalea, dolor abdominal, mareos, náuseas, vómitos, diarrea, fatiga, alteración del gusto y prurito. La eficacia y la relativamente buena tolerancia del Secnidazol fue demostrada en el presente estudio. Se obtuvo cura parasitológica al tercer día de administrado el medicamento

Enteroparasitos en niños residentes en zona rural del Partido del Carmen de Patagones: Provincia de Buenos Aires, Argentina / Enteroparasites in children living in rural areas at the Partido de Carmen de Patagones: province of Buenos Aires, Argentina

Como parte del programa de atención primaria de la salud (APS) del año 1996, y en virtud que no existían datos epidemiológicos referidos a enteroparásitos hallados en niños de 0 a 14 años, residentes en una zona rural del Partido de Carmen de Patagones, Provincia de Buenos Aires, es que se realizó el presente estudio epidemiológico descriptivo. Se estudiaron 210 niños a los que se les efectúo un estudio parasitoscópico seriado de materia fecal y mucus anal. Los resultados mostraron que el 60,5 por ciento de la población estudiada era portadora de algún parásito intestinal. El monoparasitismo hallado fue de 67 por ciento, mientras que 33 por ciento restante presentó entre 2 y 5 formas parasitarias. El espectro parasitario fue el siguiente: entamoeba coli 31,5 por ciento, giardia lamblia 24,7 por ciento; enterobius vermicularis 18 por ciento; hymenolepis nana 10,4 por ciento; blastocystis hominis 10,4 por ciento; 10,3 por ciento; chilomastix mesnili 2,5 por ciento; entamoeba hystolytica 0,9 por ciento y trichuris 0,5 por ciento. La distribución parasitaria en los distintos sectores estudiados fue en general homogénea excepto para H. nana la cual presentó una prevalencia más altas en zonas de riesgos con relación a la zona seca. Los resultados obtenidos fueron comunicados a las autoridades sanitarias correspondientes

Prevalencia de parasitosis intestinales en círculos infantiles de la provincia Ciego de Avila, Cuba: 1989-1993 / Prevalence of intestinal parasitic infections in nursery schools from Ciego de Avila Province, Cuba: 1989-1993

The prevalence of intestinal parasitsm in nursery school from Ciego de Avila province was annually avaluated during 1989-1993. The percentage of infected children ranged from 16.6 percent to 31.6 percent. An increase of frequence of infection was observer from 1991. Protozoa were more predominant than helminths. In the whole five-year period studied giardia intestinalis had a higher prevalence (19.6 percent) followed by entamoeba histolytica (3.0 percent). The nematode most frequently found was trichuris trichiura (0.5 percent)

Variación estacional de las infecciones por protozoos intestinales en pacientes ambulatorios del sector norte de Santiago, Chile: 1995-1996 / Seasonal variation of intestinal protozoa infections in outpatients of the north section of Santiago, Chile: 1995-1996

Formalin preserved fecal samples from 6,058 and 5,863 outpatients were examined for intestinal parasites during 1995 and 1996 respectively. Prevalence rates of infections by intestinal protozoa in both years were similar. By age group (0-9, 10-19 and >20 years old). Blastocystis hominis was observed in 18.6-19.3, 37.0-31.1 and 25.3-25.4 percent in 1995-1996 respectively. Prevalence of giardia intestinalis infections decreased from 16.6-17.4 per cent in the 0-9 year-old children group to 4.1-4.5 percent in patients over 20 years. Overall percentages of infection by entamoeba histolytica varied between 4.2 and 10.9.Rates of infections by G. intestinalis, E. histolytica, and entamoeba coli observed during rainy-cold months (april-september) of the year versus dry-warmy period (october-march) were the same. On the contrary, more cases of B. hominis infection 25.8 percent versus 18.2 percent (this difference being statistically significant, p >0.001) were observed during rainy-cold months of the year