Astrid Carolina Flórez

Blastocystis subtypes detected in humans and animals from Colombia

Blastocystis is a common enteric protist colonizing probably more than 1 billion people along with a large variety of non-human hosts. This protist has been linked to symptoms and diseases such as abdominal pain, constipation, diarrhea, flatulence and irritable bowel syndrome (IBS). Remarkable genetic diversity has been observed, leading to the subdivision of the genus into multiple subtypes (ST), some of which are exclusively found in non-human hosts. The aim of this study was to determine the distribution of Blastocystis STs in different Colombian hosts. We obtained fecal samples positive for Blastocystis by microscopy from 277 humans, 52 birds, and 117 mammals (25 cattle, 40 opossums, 40 dogs, 10 rats and 2 howler monkeys). The samples were submitted to DNA extraction, PCR and sequencing using primers targeting the small subunit rRNA gene, and ST identification was performed according to DNA barcoding. We observed the occurrence of ST1 (34%) and ST2 (23%) and lower proportions of STs 3 (11.4%), 4 (0.8%), 6 (19.8%) and 8 (10.5%). Domesticated mammals shared the same STs as those usually seen in humans (ST1, ST2, ST3), while birds and marsupials had STs, which are usually rare in humans (ST6, ST8). Further studies implementing high-resolution molecular markers are necessary to understand the phylodynamics of Blastocystis transmission and the role of this stramenopile in health and disease in Colombian populations, and to expand on the phylogeographic differences observed so far with a view to exploring and understanding host-parasite co-evolution.

Molecular epidemiology of human oral Chagas disease outbreaks in Colombia.

Background Trypanosoma cruzi, the causative agent of Chagas disease, displays significant genetic variability revealed by six Discrete Typing Units (TcI-TcVI). In this pathology, oral transmission represents an emerging epidemiological scenario where different outbreaks associated to food/beverages consumption have been reported in Argentina, Bolivia, Brazil, Ecuador and Venezuela. In Colombia, six human oral outbreaks have been reported corroborating the importance of this transmission route. Molecular epidemiology of oral outbreaks is barely known observing the incrimination of TcI, TcII, TcIV and TcV genotypes. Methodology and Principal Findings High-throughput molecular characterization was conducted performing MLMT (Multilocus Microsatellite Typing) and mtMLST (mitochondrial Multilocus Sequence Typing) strategies on 50 clones from ten isolates. Results allowed observing the occurrence of TcI, TcIV and mixed infection of distinct TcI genotypes. Thus, a majority of specific mitochondrial haplotypes and allelic multilocus genotypes associated to the sylvatic cycle of transmission were detected in the dataset with the foreseen presence of mitochondrial haplotypes and allelic multilocus genotypes associated to the domestic cycle of transmission. Conclusions These findings suggest the incrimination of sylvatic genotypes in the oral outbreaks occurred in Colombia. We observed patterns of super-infection and/or co-infection with a tailored association with the severe forms of myocarditis in the acute phase of the disease. The transmission dynamics of this infection route based on molecular epidemiology evidence was unraveled and the clinical and biological implications are discussed.

Enfermedad de Chagas aguda en Colombia, una entidad poco sospechada. Informe de 10 casos presentados en el periodo 2002 a 2005

Introduction. In Colombia, reported cases of acute Chagas disease are sporadic. Objective. Ten cases were described that had been reported to the Parasitology Laboratory of the Colombian National Health Institute between December 2002 and November 2005. Materials and methods. Information from clinical records, epidemiological report forms, laboratory and blood tests was collated. In addition the following data were compiled: demographic variables, clinical findings, results of laboratory tests and other exams (such as peripheral blood smears), IFAT for IgG antibodies, isolation in culture medium, inoculation in mice, polymerase chain reaction tests and isoenzyme eletrophoresis. Results. All the cases presented in known endemic areas for Chagas disease transmission in Colombia. Three cases were from Putumayo Province, two each from the provinces of Arauca, Casanare, Norte de Santander and one from Santander Province. The probable mode of transmission was vector-borne. Seven cases presented in adults aged 18 to 50, three in children aged 6 months to 2 years. Seven were male and three were female. The most frequent symptom was fever in nine cases. Signs of portal of entry were rare; only one patient presented a possible Romana´s sign. Three patients presented myocarditis, two acute cardiac failure and one cardiac tamponade. Parasitemia was evident in nine cases; five had positive IgG serological tests; five cases were confirmed through parasite isolation; isoenzyme electrophoresis showed Trypanosoma cruzi group I. Conclusions. Clinical variability prevailed. In none of the cases was a clinical diagnosis suspected. The diagnosis was made and confirmed through laboratory tests alone. The results highlight the importance of including this disease in the differential diagnosis of febrile syndrome in endemic regions due to its good response to etiological treatment and thereby preventing its progression to the chronic phase.

First Report of Human Trypanosoma cruzi Infection Attributed to TcBat Genotype

Chagas disease is an endemic disease of the American continent caused by Trypanosoma cruzi and divided into six discrete typing units (TcI – TcVI). Nearly 10 million people harbour the infection representing a serious issue in public health. Epidemiological surveillance allowed us to detect a bat‐related T. cruzi genotype (henceforth named TcBat) in a 5‐year‐old female living in a forest area in northwestern Colombia. Molecular tools determined a mixed infection of T. cruzi I and TcBat genotypes. This represents the first report of TcBat infection in humans; the epidemiological consequences of this finding are discussed herein.

Follow-up of an asymptomatic Chagas disease population of children after treatment with nifurtimox (Lampit) in a sylvatic endemic transmission area of Colombia.

Background Chagas disease is an anthropozoonosis caused by Trypanosoma cruzi. Two drugs are currently used for the etiological treatment of the disease: Nifurtimox (Lampit) and Benznidazole. This study presents a quasi-experimental trial (non-control group) of sixty-two patients who were treated for Chagas disease with Nifurtimox (Lampit), and were then followed for 30 months post-treatment. The safety of Nifurtimox (Lampit) for Chagas disease in this group of children primarily between 4 and 19 years old was also evaluated. Materials and methods The 62 patients included in the study were selected when resulted seropositive for two out of three fundamentally different serological tests. All children were treated during two months according to protocols established by WHO. Monitoring was performed every twenty days to evaluate treatment safety. In 43 patients, two different serological tests: ELISA and IFAT; and two parasitological tests: blood culture, and real time PCR, (qPCR) were performed to assess therapeutic response, defined as post-treatment serological negativization. Principal findings All patients completed the treatment successfully, and six patients abandoned the post-treatment follow-up. Adverse effects occurred in 74% of patients, but only 4.8% of cases required temporary suspension to achieve 100% adherence to the 60-day treatment, and all symptoms reverted after treatment completion. Both parasite load (measured through qPCR) and antibodies (ELISA absorbance) evidenced a significant median reduction 6 months after treatment from 6.2 to 0.2 parasite equivalents/mL, and from 0.6 to 0.2 absorbance units respectively (p<0.001). Serological negativization by ELISA was evident since 6 months post-treatment, whereas by IFAT only after 18 months. Serological negativization by the two tests (ELISA and IFAT) was 41.9% (95%CI: 26.5–57.3) after 30 months post-treatment. qPCR was positive in 88.3% of patients pre-treatment and only in 12.1% of patients after 30 months. Survival analysis indicated that only 26.3% (95%CI: 15.5–44.8) persisted with negative qPCR during the whole follow-up period. Conclusions Nifurtimox was very well tolerated and successfully reduced parasite load and antibody titers. Re-infection, lysed parasites or a lack of anti-parasitic activity could explain these persistently positive qPCR cases.

Prevalence and Risk Factors for Chagas Disease in Pregnant Women in Casanare, Colombia

Knowledge of the prevalence and risk factors associated with maternal infection is the first step to develop a surveillance system for congenital transmission of Chagas disease. We conducted a cross-sectional study in Casanare, a disease-endemic area in Colombia. A total of 982 patients were enrolled in the study. A global prevalence of Trypanosoma cruzi infection of 4.0% (95% confidence interval [CI] = 2.8-5.3%) was found. Multivariate analysis showed that the most important risk-associated factors were age > 29 years (adjusted odds ratio [aOR] = 3.4, 95% CI = 0.9-12.4), rural residency (aOR = 2.2, 95% CI = 1.0-4.6), low education level (aOR = 10.2, 95% CI = 1.6-82.7), and previous knowledge of the vector (aOR = 2.2, 95% CI = 1.0-4.9). Relatives and siblings of infected mothers showed a prevalence of 9.3%. These findings may help physicians to investigate congenital cases, screen Chagas disease in siblings and relatives, and provide early treatment to prevent the chronic complications of Chagas disease.

Serological response to Helicobacter pylori infection among Latin American populations with contrasting risks of gastric cancer

Gastric cancer is a rare outcome of chronic Helicobacter pylori infection. Serologic profiles may reveal bacterial, environmental and/or host factors associated with cancer risk. We therefore compared specific anti‐H. pylori antibodies among populations with at least twofold differences in gastric cancer mortality from Mexico, Colombia and Chile. Our study included 1,776 adults (mean age 42 years) from three nationally representative surveys, equally divided between residents of high‐ and low‐risk areas. Antibodies to 15 immunogenic H. pylori antigens were measured by fluorescent bead‐based multiplex assays; results were summarized to identify overall H. pylori seropositivity. We used logistic regression to model associations between antibody seroreactivity and regional cancer risk (high vs. low), adjusting for country, age and sex. Both risk areas had similar H. pylori seroprevalence. Residents in high‐ and low‐risk areas were seroreactive to a similar number of antigens (means 8.2 vs. 7.9, respectively; adjusted odds ratio, OR: 1.02, p = 0.05). Seroreactivities to Catalase and the known virulence proteins CagA and VacA were each significantly (p < 0.05) associated with residence in high‐risk areas, but ORs were moderate (1.26, 1.42 and 1.41, respectively) and their discriminatory power was low (area under the curve < 0.6). The association of Catalase was independent from effects of either CagA or VacA. Sensitivity analyses for antibody associations restricted to H. pylori‐seropositive individuals generally replicated significant associations. Our findings suggest that humoral responses to H. pylori are insufficient to distinguish high and low gastric cancer risk in Latin America. Factors determining population variation of gastric cancer burden remain to be identified.

Risk factors associated with Chagas disease in pregnant women in Santander a highly endemic Colombian area.

To determine the prevalence and risk factors associated with Chagas disease in pregnant women in an endemic area of Santander, Colombia.

Frecuencia de Parasitismo Intestinal en Manipuladores de Alimentos de Cinco Ciudades de Colombia, 2008

frequency of intestinal Parasites in food Handlers in five cities in colombia, 2008 The main objective of this study was to find the frequency of intestinal parasites in food handlers working in various public restaurants, located in five capital cities of the country and in such establishments know the implementation of good manufacturing practices as a strategy for reducing parasitic morbidity and as a tool for prevention. 300 restaurants were visited where they surveyed 905 food handlers, whom they requested a stool sample were collected 766, which were analyzed by Ritchie’s concentration method (formalin-ether) and intestinal coccidian parasites using the technique Ziehl Neelsen staining. We found a high percentage of non-pathogenic parasites as Endolimax nana and Entamoeba coli, indicators of poor

Caracterización molecular de los genes histona H2A y ARNsno-Cl de Trypanosoma rangeli: aplicación en pruebas diagnósticas

La aplicacion de la reaccion en cadena de lapolimerasa (PCR) para detectar e identificarTrypanosoma cruzi y Trypanosoma rangeli presentaa menudo dificultades de interpretacion.Asi, algunas pruebas generan la amplificacionde bandas similares provenientes de uno delos dos parasitos, fragmentos polimorficos deun mismo parasito, o la prevalencia en la deteccionde T. cruzi en infecciones mixtas.