Transfusion-transmitted Chagas Disease Research Articles

Crystal violet structural analogues identified by in silico drug repositioning present anti-Trypanosoma cruzi activity through inhibition of proline transporter TcAAAP069.

BackgroundCrystal violet (CV) was used for several years in blood banks to eliminate the parasite Trypanosoma cruzi in endemic areas in order to prevent transfusion-transmitted Chagas disease. One mechanism of action described for CV involves inhibition of proline uptake. In T. cruzi, proline is essential for host cell infection and intracellular differentiation among other processes, and can be obtained through the proline permease TcAAAP069.Methodology/Principal findingsCV inhibited proline transporter TcAAAP069 and parasites overexpressing this permease were 47-fold more sensitive to this compound than control parasites. Using CV as reference molecule, loratadine, cyproheptadine, olanzapine and clofazimine were identified as structurally related compounds to CV (structural analogues) by in silico drug repurposing through a similarity-based virtual screening protocol. All these already-approved drugs for clinical use inhibited TcAAAP069 activity with different efficacies and also presented trypanocidal action in epimastigotes, trypomastigotes and amastigotes of the Y, CL Brener and Dm28c T. cruzi strains. Finally, a synergistic effect between benznidazole and the CV chemical analogues was evidenced by combination and dose-reduction indexes values in epimastigotes and trypomastigotes of the Y strain.Conclusions/SignificanceLoratadine, cyproheptadine and clofazimine inhibit TcAAAP069 proline transporter and also present trypanocidal effect against all T. cruzi life stages in strains from three different DTUs. These CV structural analogues could be a starting point to design therapeutic alternatives to treat Chagas disease by finding new indications for old drugs. This approach, called drug repurposing is a recommended strategy by the World Health Organization to treat neglected diseases, like Chagas disease, and combination therapy may improve the possibility of success of repositioned drugs.

Where do Trypanosoma cruzi go? The distribution of parasites in blood components from fractionated infected whole blood.

Platelets (PLTs) are the blood component most frequently involved in Trypanosoma cruzi transfusion transmission cases reported in the literature, although whole blood (WB) and red blood cells (RBCs) have also been incriminated. However, there is little knowledge of the parasite distribution among blood components. The aim of this study was to investigate in which blood component T. cruzi parasites concentrate the most, after fractionating artificially T. cruzi-infected WB. The T. cruzi parasite load was studied by a specific quantitative real-time polymerase chain reaction (qPCR) in WB, buffy coat (BC), PLT concentrates, RBCs before and after leukoreduction, and plasma (PL). The parasite load in WB experimentally infected with 1.5 × 10(6) parasites (2.78 × 10(3) parasite equivalents/mL) was unevenly distributed among the separated blood components. The highest level was found in the BC (6.94 × 10(3) parasite equivalents/mL) and RBCs before leukoreduction by filtration (2.51 × 10(3) parasite equivalents/mL), after which RBCs presented a 99.9% reduction in parasite levels. Both PL and PLTs, partially leukoreduced by centrifugation but nonfiltered, had low parasite levels, the lowest concentration being in PL. The highest parasite concentration was detected in the BC, followed by RBCs before leukoreduction. There is a notable risk of transfusion-transmitted Chagas disease associated with nonleukoreduced RBCs. Leukoreduction may be an effective prevention strategy for transfusion-transmitted T. cruzi infection, especially in endemic countries and in nonendemic countries with a high rate of immigration from Latin America.

A Case of Possible Chagas Transmission by Blood Transfusion in Switzerland

Background: Transfusion-transmitted Chagas disease has been reported from endemic countries in Latin America. Switzerland is a non-endemic country but high prevalence of antibodies against Trypanosoma cruzi was found among immigrants. Immigrants may participate in blood donation; therefore, risk-adapted anti-T. cruzi screening for blood donors was implemented in Switzerland in 2013. Methods: Between January 2013 and July 2015, 1 out of 1,183 at-risk donors, tested at Blood Transfusion Service Zurich, was found anti-T. cruzi IgG-positive. Results and Conclusion: Out of 54 donations given by the index donor (ID), we identified 77 blood products which were delivered to hospitals. Archived serum samples from the donations given during the prior 5 years were available for retrospective testing. All samples from ID revealed positive findings for anti-T.cruzi IgG. Donor-triggered look-back procedure identified a 70-year-old male recipient of a platelet concentrate (PC) donated by ID. The recipient succumbed of acute T. cruzi infection 2 years after transfusion of the PC.

Chagas disease and transfusion medicine: a perspective from non-endemic countries.

In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their "historical" boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas.

Os primórdios do controle da doença de Chagas (em homenagem a Emmanuel Dias, pioneiro do controle, no centenário de seu nascimento)

Very soon Carlos Chagas took into account the need of trypanosomiasis control, considering its great social impact and geographical dispersion The vector was considered the more vulnerable target and housing improvement the basic strategy to face the disease. In parallel, it was required a more clinical visibility for the disease, as an argument for its control. The first concrete tentative occurred in 1918 when Souza Araújo dedicating his efforts in Paraná, trying housing improvement. He was followed by Ezequiel Dias et al, in 1921, employing chemical compounds against the vector, The chemical fight will be retaken by Emmanuel Dias in 1944, assaying several old compounds, fire thrower and cyanidric gas. In 1946, DDT showed to be ineffective, but one year later Dias & Pellegrino described the insecticide gammexane, highly effective against domestic triatomines. Working with Mario Pinotti, expanded trials occurred in Minas Gerais (Triangle Region), justifying the expansion of the campaign to other endemic regions, with the rationale of continuous work in contiguous areas. In 1957 Pedreira de Freitas proposed the selective spraying, which was the model for the future strategy of program evaluation, by SUVEN and SUCAN organizations. In 1975 the national program is reorganized, launching two national surveys (entomology and serology). In 1979 the new pyrethroid compounds are tried and im 1983 the national program is expanded. Transfusion transmitted Chagas Disease was studied since the 1950 by the Nussenzweig group in S. Paulo, showing to be vulnerable to chemoprophylaxis and blood donor pre transfusional serologic screening. Nevertheless, these preventive measures only were implemented in the 1980 decade, following the emergence of HIV/AIDS pandemic. Practically, since the pioneer essays, the control of Chagas Disease transmission showed to be efficient against vector and blood bank mechanisms, depending on continuity, educative support and political will.

Transfusion transmitted Chagas disease: Is it really under control?

Transfusion transmitted Chagas disease was recognized as a medical problem more than 50 years ago. However, little attention was paid to it by Transfusion Medicine, medical authorities or regulatory agencies as a major problem and threat (especially after the advent of HIV/AIDS); perhaps because it was mainly restricted to tropical regions, usually in less developed countries. With the intense human migratory movement from developing to developed countries, it became more common and evident. The scope of this review is to cover the main transfusional aspects of American trypanosomiasis (Chagas disease), including the main strategies to prevent it through donor questionnaires, specific serological testing and alternative methods such as leukofiltration and pathogen reduction procedures, in order to increase the blood safety in both developing and developed countries.

Prevalence of transfusion-transmitted Chagas disease among multitransfused patients in Brazil

BackgroundBlood transfusion has always been an important route for Chagas Disease (CD) transmission. The high prevalence of CD in Latin America and its lifelong asymptomatic clinical picture pose a threat for the safety of the blood supply. The outcome of measures designed to improve transfusion safety can be assessed by evaluating the prevalence of CD among multitransfused patientsMethodsIn order to assess the impact of CD control measures on the safety of the blood supply, an observational cross-sectional study was designed to determine the prevalence of CD in 351 highly transfused patients, in which vectorial transmission was excluded. This study compared patients that received transfusion products before (n = 230) and after (n = 121) 1997, when measures to control transfusion-transmitted CD were fully implemented in Brazil.ResultsThe study group consisted of 351 patients exposed to high numbers of blood products during their lifetime (median number of units transfused = 51, range 10–2086). A higher prevalence of transfusion-transmitted CD (1.30%) was observed among multitransfused patients that received their first transfusion before 1997, compared with no cases of transfusion-transmitted CD among multitransfused patients transfused after that year. The magnitude of the exposure to blood products was similar among both groups (mean number of units transfused per year of exposure = 25.00 ± 26.46 and 23.99 ± 30.58 respectively; P = 0.75, Mann-Whitney test).ConclusionMultiple initiatives aimed to control vector and parental transmission of CD can significantly decrease transfusion-transmitted CD in Brazil. Our data suggest that mandatory donor screening for CD represents the most important measure to interrupt transmission of CD by blood transfusions.

The efficacy of photochemical treatment with methylene blue and light for the reduction of Trypanosoma cruzi in infected plasma

Chagas disease is a transfusion-transmitted infection. This study evaluates the efficacy of a methylene blue (MB) and light system for reducing the viability of Trypanosoma cruzi in plasma. MATERIALS AND METHODS Trypanosoma cruzi strains were spiked in plasma pools. Treatment arms included combined filtration, MB, light and freezing. Post-treatment parasite viability was assayed through in vitro cultures and in vivo inoculation in inducible nitric oxide synthase- and interferon-gamma-receptor-deficient mice. The filtration, MB and light combined treatment showed a log reduction of > 3.4 in in vitro cultures, and log reductions that ranged from > 4.9 to > 5.8 in deficient mice inoculated with different T. cruzi strains. The treatment of plasma units with the MB and light system reduces the T. cruzi burden and could be useful in preventing transfusion-transmitted Chagas disease.

Intervention strategies to reduce the risk of transfusion-transmitted Trypanosoma cruzi infection in the United States

N SOME metropolitan areas of the United States, approximately 1 in 9,000 blood donations is obtained from a donor who is seropositive for specific antibodies to Trypanosoma cruzi. In some areas of Los Angeles, nearly 1 in every 550 eligible blood donors is seropositive. The transfusion of seropositive blood products can lead to transfusion-transmitted Chagas disease, because at least half 6f Tcruzi-seropositive donors are parasitemic. Transfusion-associated transmission of Chagas disease has occurred on at least four occasions in the United States and once in Canada during the past 12 years. It has been suggested that the risk of transfusiontransmitted Chagas disease could be reduced if donors were questioned for a history of birth, extended stay, or transfusion in a geographic area endemic for Chagas disease, or were tested for serological evidence of antibodies to T cruzi. However, a policy to question or test donors for evidence of T cruzi infection should only be implemented if it can be shown to improve the overall safety of the US blood supply; without causing a deleterious reduction in the availability of blood.

Absence of serological surrogate markers for Trypanosoma-cruzi-infected blood donors.

Specific serological screening tests for Trypanosoma-cruzi-infected donors are not yet available and thus not routinely performed in North America. With the recent increase of Latin-American immigration to North America and Europe, there is a risk of transmission by blood products. In this study, we evaluated the possibility whether any of the serological screening tests currently recommended by the AABB could be used as a surrogate marker for this protozoarium. A group of 26,365 blood donors (male = 21,053 and female = 5,312) was analysed for the correlation of T. cruzi antibodies (TcAb) with other serological markers (HIV, HBsAg, ALT, HTLV-I/II, HCV, Anti-HBc, syphilis and unexpected hemoglobins other than A1, A2 and F). Association could be demonstrated only between syphilis and TcAb in the female group (p = 0.005), but the low number of donors found with this association (n = 4) renders the effect of this correlation very small. A higher prevalence of TcAb was found in older age groups, with even gender distribution (p < 0.05), however, donors aged more than 54 years also represent a minority of the donor pool (4.83%) and the detection of positive donors in this age group also has a minor preventive effect on transfusion-transmitted Chagas disease. We conclude that when infected blood donors must be detected, specific serological screening for TcAb is essential and that currently no surrogate marker can be considered for detecting T. cruzi-infected blood donors.

Screening in vitro of natural products against blood forms of Trypanosoma cruzi

Transmission of Chagas disease by blood transfusion is a major health problem in Central and South America. The annual incidence of transfusion-transmitted Chagas disease in Brazil is about 20 000 cases. Crystal violet is the only trypanosomicidal agent available at present, but there are some restrictions on its use. In a search for possible new chemoprophylactic agents, several natural products of different structural types were tested in vitro against infective blood trypomastigptes of Trypanosoma cruzi. Four compounds had high activity at a concentration of 5 × 10 −4 m: the diarylpropanoids (3R)-claussequinone, (R)-4-methoxydalbergione and (S)-4,4′-dimethpxydalbergione, and 15-deoxygoyazensolide, a sesquiterpenelactone. Haemoculture and serology of mice inoculated with infected blood treated with these active compounds were negative after 3 and 6 months. The benzpquinpne moiety seemed to be important for this activity since lapachol and related naphthoquinones are known to be trypanosomicidal. 15-Deoxygoyazensolide has previously been recognized as a schistosomicide.