Ruth López

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

Blood transfusion and iatrogenic risks in Mexico city: anti-Trypanosoma cruzi seroprevalence in 43,048 blood donors, evaluation of parasitemia, and electrocardiogram findings in seropositive

Iatrogenous transmission of Trypanosoma cruzi by blood transfusion was suggested as a potential risk by Pellegrino (1949). Seropositive blood donors in Mexico were first reported in 1978, however, limited information is available due to small sampling, the use of heterogeneous serologic assays, and geographically limited studies. A wide survey carried out in 18 out of the 32 states of Mexico, showed a national mean of 1.6% seropositive among 64,969 donors, ranging from 0.2 to 2.8%. In the present study, we have screened 43,048 voluntary blood donors in a period of five years at the Instituto Nacional de Cardiología I. Chávez, a concentration hospital located in Mexico city which serves mainly the metropolitan area and accepts from all over the country. Standardized ELISA and IIF were used to identify seropositive individuals in addition to hemoculture, PCR and standard 12 lead ECG tests that were applied to a group of seropositive patients (29/161). The result showed a seropositivity of 0.37% (161/43,048). From the group of seropositive individuals 40% (12/29) were potential carriers of T. cruzi at the donation time and 5/29 had subclinical ECG abnormalities. Parasitological tests performed in 70 erythrocyte and platelet fractions from seropositive units (70/161) showed negative results. Our findings strongly support T. cruzi screening in the transfusion medicine practice and identify subclinical heart disease among seropositive blood donors.

Performance levels of four Latin American laboratories for the serodiagnosis of Chagas disease in Mexican sera samples.

In nearly all of the previous multicentre studies evaluating serological tests for Trypanosoma cruzi infection, sera samples from Central or South American countries have been used preferentially. In this work we compared the reliability of the serological tests using Mexican sera samples that were evaluated in four independent laboratories. This included a reference laboratory in Brazil and three participant laboratories, including one in Central America and two in Mexico. The kappa index between Brazilian and Honduran laboratories reached 1.0 and the index for the Mexican laboratories reached 0.94. Another finding of this study was that the source of antigen did not affect the performance of the serological tests.

High Frequency of Human Blood in Triatoma dimidiata Captured Inside Dwellings in a Rural Community in the Yucatan Peninsula, Mexico, but Low Antibody Seroprevalence and Electrocardiographic Findings Compatible with Chagas Disease in Humans

We studied a small rural community of 411 inhabitants localized in the state of Campeche in the Yucatan Peninsula, Mexico. In 44 collected triatomines captured inside the houses, human feeding source was revealed in 23 of 44 (52%) samples, and chicken feeding source was revealed in 16 of 44 (36%) samples. In a set of 29 triatomines, mouse was the feeding source in 13 (44%) samples, and dog was the feeding source in 7 (24%) samples. Infection index with Trypanosoma cruzi in collected triatomines was 38%, and all parasites belonged to discrete type unit I. Inhabitants referred high contact with triatomines bite in 60 of 128 (47%) samples, but seroprevalence was 2.3% (3/128). Evidence of electrocardiographic alteration compatible with Chagas disease was observed only in one asymptomatic seropositive subject. In conclusion, Triatoma dimidiata in this region are preferentially infected with T. cruzi I and feed on human beings with relative high frequency, but seroprevalence and Chagas disease in humans is relatively low.

Leukoreduction by centrifugation does not eliminate Trypanosoma cruzi from infected blood units.

Current strategies to prevent transfusion-associated Chagas disease include the identification of Trypanosoma cruzi-infected blood donors through questionnaires and serologic tests. There are other procedures such as leukoreduction that prevent the transmission of infectious agents associated to white cells. The objective of the present work was to estimate the seroprevalence, evaluate the efficacy of leukoreduction by centrifugation to eliminate T. cruzi in infected blood units, and the correlation of immunoglobulin G (IgG) subclasses of seropositive blood donors with chronic chagasic cardiopathy. Over a period of 14 months, 33 out of 6600 blood donors (0.5%) at Centro Estatal de la Transfusión Sanguínea in Campeche State, México were seropositive for T. cruzi. Twenty seropositive blood units were submitted through leukoreduction by centrifugation, and in the fractions generated (red cell fraction, platelets, and the buffy-coat), we searched for the presence of T. cruzi using specific polymerase chain reaction. We detected parasite DNA in 50% to 60% of the fractions tested, suggesting that leukoreduction by centrifugation does not eliminate the microorganisms in the infected blood unit. We also observed that the level of IgG2 and IgG4 subclasses specific for T. cruzi in seropositive blood donors was lower than in chronic cardiopathic chagasic patients. In conclusion, leukoreduction by centrifugation has a limited role in eliminating T. cruzi in infected blood supply, and the low level of specific IgG2 and IgG4 could be a marker in the indeterminate phase of infection.

Enzyme-linked immunosorbent assay and polymerase chain reaction performance using Mexican and Guatemalan discrete typing unit I strains of Trypanosoma cruzi.

Thirteen Trypanosoma cruzi isolates from different geographic regions of Mexico and Guatemala belonging to discrete typing unit (DTU) I and a reference CL-Brener (DTU VI) strain were used to perform enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). A panel of 57 Mexican serum samples of patients with chronic chagasic cardiopathy and asymptomatic infected subjects (blood bank donors) were used in this study. DNA from the above 14 T. cruzi strains were extracted and analyzed by PCR using different sets of primers designed from minicircle and satellite T. cruzi DNA. The chronic chagasic cardiopathy serum samples were easily recognized with ELISA regardless of the source of antigenic extract used, even with the CL-Brener TcVI, but positive serum samples from blood bank donors in some cases were not recognized by some Mexican antigenic extracts. On the other hand, PCR showed an excellent performance despite the set of primers used, since all Mexican and Guatemalan T. cruzi strains were correctly amplified. In general terms, Mexican, Guatemalan, and CL-Brener T. cruzi strains are equally good sources of antigen when using the ELISA test to detect Mexican serum samples. However, there are some strains with poor performance. The DTU I strains are easily detected using either kinetoplast or satellite DNA target designed from DTU VI strains.

Decreased Intensity of Inflammation in Benznidazole-Treated Mice Inoculated with Trypanosoma cruzi I Stocks from Mexico and Persistence of Circulating Parasites

We analyzed the intensity of inflammation and parasitism in BALB/c mice infected with Trypanosoma cruzi I stocks from Mexico with and without benznidazole treatment in the acute phase of disease. Heart and skeletal muscles were evaluated for parasites and inflammation and blood was evaluated for persistence of circulating parasites. Parasitemia was influenced by T. cruzi stocks used and benznidazole treatment. This treatment cleared circulating parasites three days after starting treatment when monitored by direct microscopy. There was a significant reduction of inflammation in skeletal muscles after benznidazole treatment in animals infected with Mexican T. cruzi I stocks (P < 0.05), but this reduction was not significant in the heart (P > 0.05). Trypanosoma cruzi I parasites from Mexico were demonstrated by polymerase chain reaction in tissues and blood of animals after benznidazole treatment.

1504PINCIDENCE OF CHEMOTHERAPY-INDUCED NAUSEA AND VOMITING WITH MODERATELY EMETOGENIC CHEMOTHERAPY: ADVICE STUDY

ABSTRACT Background: Limited information regarding incidence of chemotherapy induced nausea and vomiting (CINV) is available in patients receiving moderately emetogenic chemotherapy (MEC). Methods: Chemotherapy-naive patients receiving MEC, between April-2012 and May-2013 were included in an observational and prospective trial evaluating incidence of CINV during 120 hours post-chemotherapy as primary endpoint. Patients completed a diary to capture intensity of nausea and number of vomiting episodes. Complete response (no vomiting or rescue medication use) and complete protection (no vomiting and no severe nausea or use of rescue medication) were assessed as secondary endpoints. Results: Of 261 patients included, 240 were evaluated. The median age was 64.36 years (36.15-87.3), 44.17% were female and 11.25% were aged less than 50 years. The majority, 95.3% of patients received a combination of a 5-HT3 antagonist+corticosteroid as antiemetic treatment. Episodes of vomiting within 5 days of chemotherapy administration occurred in 20.78% of patients, nausea of any intensity in 42% (≥5 mm to 100mm VAS (visual analog scale)), and significant nausea in 23.8% of patients (≥25 mm to 100 mm VAS). An increase in the percentage of patients with severe nausea and vomiting was observed from the acute to the delayed phase, from 9.44% to 21.65% and from 9.24% to 15.45% respectively. Complete response in the acute phase was 85%, 77% in the late phase and 68.9% in the overall study period. Complete protection was 79.5% in the acute phase, 69.7% in the late phase and 62.4% throughout the study period. Physicians estimated prophylaxis would be effective (no vomiting or nausea and no use of rescue medication) for 75% of patients receiving MEC, compared with 54.1% obtained from patients diary. Conclusions: Despite receiving prophylactic treatment, 31% of patients did not achieve a complete response and 38% patients did not achieve complete protection. In general nausea was worse controlled than vomiting. The results also showed the late phase was worse controlled than the acute phase in all variables. Healthcare providers overestimated the effectiveness of antiemetic prophylaxis. Disclosure: P. Del Barrio: Employee of Merck Sharp & Dohme; M.V. Tornamira: Employee of Merck Sharp & Dohme. All other authors have declared no conflicts of interest.