Margarita Samudio

Efficacy of the bisbenzylisoquinoline alkaloids in acute and chronic Trypanosoma cruzi murine model

We have shown previously that daphnoline and cepharanthine are active against Trypanosoma cruzi and inhibited trypanothione reductase. The effects of oral treatments with daphnoline, cepharanthine and benznidazole were examined in Balb/c mice infected with T. cruzi acutely and chronically. In acute infections, parasitaemia was significantly reduced in the daphnoline-treated mice compared with controls and benznidazole-treated mice. The parasitological cure rate was increased in mice treated with daphnoline. Fifty days after infection, the negative serological response in both models was significantly different for the three tested drugs. Daphnoline showed the highest negative serological rate (48%). In chronically infected mice treated with daphnoline, we were unable to detect parasites in 70% of mice. The results obtained of oral treatment of daphnoline suggest that this bisbenzylisoquinoline may be useful in the treatment of acute and chronic Chagas disease. This was not seen with cepharanthine, an excellent trypanothione reductase inhibitor.

Local and systemic cytokine expression during experimental chronic Trypanosoma cruzi infection in a Cebus monkey model.

Cebus apella is an acceptable model for chronic chagasic cardiomyopathy (CCC), since it is possible to experimentally induce cardiac lesions after 1 year of Trypanosoma cruzi infection. The T. cruzi Y strain, shown previously to produce CCC in C. apella monkeys, was used to experimentally infect 10 monkeys. Parasitological, serological and clinical parameters were monitored during a 19‐month follow‐up, and systemic cytokine responses were assessed sequentially in five monkeys selected according to the differential parasitemia pattern exhibited. Ten additional monkeys, infected with the same strain for 5, 10 and 12 years, were analysed cross‐sectionally. Three monkeys/time point and one uninfected control animal were sacrificed for gross pathology, histology, presence of parasites, and local cytokine gene expression. Elevated expression of interleukin (IL)‐4 was observed throughout the study in monkeys that had persistent, high parasitemias, whereas a high level of interferon (IFN)‐γ was seen in monkeys that controlled parasitemias soon after infection. Chronically infected monkeys expressed a nonpolarized, Th0‐type response. Cardiac tissue collected from a monkey that succumbed to acute infection had elevated levels of proinflammatory cytokine [IL‐1β, IL‐6, tumour necrosis factor‐α] and interstitial cell adhesion molecule (ICAM)‐1, platelet‐derived growth factor (PDGF)‐α, transforming growth factor (TGF)‐β and IL‐10 transcripts. Cytokine production in cardiac tissue of chronically infected monkeys was also characterized by elevated expression of ICAM‐1, PDGF‐α and TGF‐β, which correlated with the detection of T. cruzi DNA by polymerase chain reaction.

Differential expression of systemic cytokine profiles in Chagas' disease is associated with endemicity of Trypanosoma cruzi infections

Chagas disease is a serious public health problem in Paraguay, however, the immunoepidemiology of the disease has not been well documented. A preliminary cross-sectional survey was carried out in two villages of the Paraguayan Chaco region and in five villages of the Oriental region to assess the endemicity of Trypanosoma cruzi infections. Thereafter, a subset of individuals (ages ranging from 23 to 65 years) participated in a follow-up study to evaluate clinical and parasitological parameters. Physical examinations and electrocardiograms (ECG) were conducted and blood samples collected for parasite detection and serology. The most frequent ECG abnormalities which were observed among chagasic individuals were left anterior hemifascicular block and right bundle branch block. Thirty-two of these subjects, seropositive and non-parasitemic from the high endemic Chaco (n = 16) and low endemic Oriental (n = 16) regions, were randomly selected for an analysis of T. cruzi-induced expression of cytokines IL-2, IFN-gamma, IL-4 and IL-10 by RT-PCR. The individuals were grouped (n = 8) according to the presence or absence of abnormal ECG. In subjects that exhibited abnormal ECG profiles, five of eight (63%) individuals from the high endemic area showed a dominant type 2 (IL-4) response, whereas a comparable number (63%) of subjects from the low endemic area expressed a strong type 1 (IFN-gamma) response; the remainder (37%) presented a Th0-type (IFN-gamma, IL-4) response. Subjects with normal ECG showed a defined cytokine profile according to endemicity. All subjects from the high endemic region showed a Th0 response, whereas 100% of the individuals from the low endemic area demonstrated a type 1 response. In most chagasic patients regardless of ECG profile and endemicity, IL-2 expression was depressed, while IL-10 mRNA transcripts were consistently elevated. Taken together, these data indicate that chronic human chagasic disease is associated with increased systemic production of type 2 cytokines in response to T. cruzi infection and may be involved in the reciprocal down-regulation of IL-2 production.

Isoenzyme profiles of Trypanosoma cruzi stocks from different areas of Paraguay

Twenty one Trypanosoma cruzi stocks from humans, domiciliary triatomines and one sylvatic animal of different areas of Paraguay were subjected to isoenzyme analysis. Thirteen enzyme systems (15 loci in total) were studied. MN cl2 (clonets 39) and SO34 cl4 (clonets 20) were used as references. Relationships between stocks were depicted by an UPGMA dendrogram constructed using the Jaccards distances matrix. Among the Paraguayan stocks 14 zymodemes were identified (Par1 to Par14), Par 5 being the most frequent. Polymorphism rate and clonal diversity were 0.73 and 0.93, respectively. Average number of alleles per polymorphic locus was 2.5 (range 2-4). These measurements show a high diversity, which is confirmed by the dendrogram topology. All stocks belong to the same lineage, as MN cl2 reference strain (T. cruzi II). Moreover three distinct subgroups were identified and two of them correspond to Brazilian and Bolivian zymodemes, respectively. The third subgroup, the most common in Paraguay, is related to Tulahuen stock. The large geographical distribution of some zymodemes agrees with the hypothesis of clonality for T. cruzi populations. However sample size was not adequate to detect genetic recombination in any single locality.

Chickenpox outbreak originated in a military school in a community in Paraguay

Introduction : Chickenpox is an infectious disease of worldwide distribution, caused by primary infection of varicella zoster virus (VZV), is characteristic of childhood. Man is the only known reservoir. In tropical climates, the pattern is not so obvious, the virus circulates less frequently and the disease are acquired at later ages. In May 2013, following the notification of four cases of chickenpox to the Directorate General of Health Surveillance in a military school, research was conducted. Objective : To confirm the outbreak and to propose recommendations for prevention and control. Materials and Methods : cross sectional descriptive study. Were conducted Active retrospective search according to the following definition: a person from the Military School (MS) who presented with skin lesions, fever or sore throat between epidemiological weeks 14 and 21. Suspected cases was interviewed using a semi-structured questionnaire. Results : In addition to the four cases already reported, we identified 12-suspected cases more, but they were discarded later. The cases were all males aged 20-24 years old, with no history of varicella, one required hospitalization and antiviral treatment, four had skin lesions, three had fever and one had sore throat. Conclusion : The outbreak was confirmed in a closed institution, which originated in a community of Quiindy district. All cases were temporally related to the first case found in the community. The preventive measure for cadets (students) was the home insulation so that contagion was prevented in other students of MS. Immunization against chickenpox outbreaks recommended, intensify surveillance in health services so that the system is sensitive enough to respond in a more timely manner to such events and home insulation both in closed populations as well in the community.

Effect of antibiotic prophylaxis on Coagulase-negative Staphylococcus virulence factor profiles in patients undergoing cataract surgery

PurposeIn this prospective study, multiplex polymerase chain reaction (PCR) was used to identify genes encoding virulence factors (ica, atlE and mecA) in Coagulase-negative Staphylococcus (CNS) isolates from the ocular microbiota of patients undergoing cataract surgery and to investigate possible changes in the CNS profile due to antibiotic prophylaxis.MethodsBetween 09/2011 and 08/2013, patients undergoing cataract surgery were recruited at the Department of Ophthalmology, National University of Asuncion, Paraguay. In the eye to be operated on, patients received moxifloxacin 0.5xa0% eye drops four times at the day before surgery and a last drop 1xa0hour before surgery (T1). The other eye remained as control (T0). Conjunctival swabs were taken from both eyes 1xa0hour after the last drop. The presence of genes encoding biofilm formation (ica and atlE) and methicillin resistance (mecA) was detected by a multiplex PCR.ResultsOf the 162 patients (162 study eyes, 162 fellow eye as control group), 87 (53.7xa0%) eyes were positive for CNS at T0 yielding 96 CNS isolates; 70 eyes (43.2xa0%) were positive at T1 yielding 77 CNS isolates. For this study, 43 CNS isolates (44.8xa0%) from T0 and 45 (64.3xa0%) from T1 were used. Of the total isolates, 81.8xa0% (72/88) had at least one virulence factor gene (37/43 from T0 and 35/45 from T1) (pxa0=xa00.314). Simultaneous detection of ica and atlE genes was higher in T0 (58.0xa0%) than T1 (46.7xa0%), but the difference was not significant (pxa0=xa00.28).ConclusionA high frequency of genes encoding virulence factors was observed in the coagulase-negative Staphylococcus isolates. The use of moxifloxacin did not significantly modify the CNS virulence factor profiles.