International survey of strategies to mitigate transfusion-transmitted Trypanosoma cruzi in non-endemic countries, 2016-2018

Deferral of blood donors who have ever stayed in a Trypanosoma cruzi endemic area: An international survey

BACKGROUND AND OBJECTIVES

Trypanosoma cruzi is the etiologic agent of Chagas disease (CD), an anthropozoonosis from the American continent that progresses from an acute phase to an indeterminate phase, followed by a chronic symptomatic phase in around 30% of patients. In countries where T. cruzi is not endemic, many blood transfusion services test blood donors who have stayed in an endemic country ('at-risk stay')-even if they do not present with other risk factors. However, the efficiency of this approach has been questioned.

MATERIALS AND METHODS

On 18 September 2023, a worldwide survey was distributed among employees of blood transfusion services. The questions mainly pertained to CD's endemicity in the blood services' region, the current testing policy for T. cruzi and the number of confirmed positive results among donors with a prior at-risk stay alone (i.e., without other risk factors for T. cruzi infection).

RESULTS

Twenty-six recipients completed the survey. Of the 22 (84.6%) blood services that operated in a non-endemic region, 9 (42.9%) tested donors for T. cruzi, including 8 (88.9%) that considered the travel history or the duration of the stay (alone) in their testing algorithm ('study blood services'). Over 93 years of observation among all study blood services, 2 donations from donors with an at-risk stay alone and 299 from those with other risk factors were confirmed positive for T. cruzi.

CONCLUSION

The study findings question the utility of testing blood donors who have stayed in an endemic country without other risk factors.

New insights into Trypanosoma cruzi genetic diversity, and its influence on parasite biology and clinical outcomes

Chagas disease, caused by Trypanosoma cruzi, remains a serious public health problem worldwide. The parasite was subdivided into six distinct genetic groups, called "discrete typing units" (DTUs), from TcI to TcVI. Several studies have indicated that the heterogeneity of T. cruzi species directly affects the diversity of clinical manifestations of Chagas disease, control, diagnosis performance, and susceptibility to treatment. Thus, this review aims to describe how T. cruzi genetic diversity influences the biology of the parasite and/or clinical parameters in humans. Regarding the geographic dispersion of T. cruzi, evident differences were observed in the distribution of DTUs in distinct areas. For example, TcII is the main DTU detected in Brazilian patients from the central and southeastern regions, where there are also registers of TcVI as a secondary T. cruzi DTU. An important aspect observed in previous studies is that the genetic variability of T. cruzi can impact parasite infectivity, reproduction, and differentiation in the vectors. It has been proposed that T. cruzi DTU influences the host immune response and affects disease progression. Genetic aspects of the parasite play an important role in determining which host tissues will be infected, thus heavily influencing Chagas disease's pathogenesis. Several teams have investigated the correlation between T. cruzi DTU and the reactivation of Chagas disease. In agreement with these data, it is reasonable to suppose that the immunological condition of the patient, whether or not associated with the reactivation of the T. cruzi infection and the parasite strain, may have an important role in the pathogenesis of Chagas disease. In this context, understanding the genetics of T. cruzi and its biological and clinical implications will provide new knowledge that may contribute to additional strategies in the diagnosis and clinical outcome follow-up of patients with Chagas disease, in addition to the reactivation of immunocompromised patients infected with T. cruzi.

Chagas disease

Chagas disease persists as a global public health problem due to the high morbidity and mortality burden. Despite the possibility of a cure and advances in transmission control, epidemiological transformations, such as urbanisation and globalisation, and the emerging importance of oral and vertical transmission mean that Chagas disease should be considered an emerging disease, with new cases occurring worldwide. Important barriers to diagnosis, treatment, and care remain, resulting in repressed numbers of reported cases, which in turn leads to inadequate public policies. The validation of new diagnostic tools and treatment options is needed, as existing tools pose serious limitations to access to health care. Integrated models of surveillance, with community and intersectional participation, embedded in the concept of One Health, are essential for control. In addition, mitigation strategies for the main social determinants of health, including difficulties imposed by migration, are important to improve access to comprehensive health care in a globalised scenario.

Infectious diseases and the impact on transfusion medicine: A historical review and lessons for the future

Blood transfusion saves millions of lives each year. It is a well-established treatment, and many procedures are applied to avoid transmitted infections. However, throughout the history of transfusion medicine, many infectious diseases arose or were recognised, bringing up an impact on the blood supply, as the difficulties in diagnosing new diseases, the decrease in blood donors, the challenges for the medical team, the risks for the receptor and the related costs. This study aims to review historically the principal infectious diseases transmitted through the blood that circulated worldwide in the 20th and 21st centuries, considering the impact on the blood banks. Despite the current blood bank control of transfusion risks and the hemovigilance improvements, transmitted and emerging infections can still compromise the blood bank supply, as we have witnessed during the first waves of the COVID-19 pandemic. Moreover, new pathogens will continue emerging, and we must be prepared for the future.

Arylimidamides Have Potential for Chemoprophylaxis against Blood-Transmitted Chagas Disease

Chagas disease (CD) affects over 6 million people worldwide and can be transmitted iatrogenically. Crystal violet (CV) was previously used for pathogen reduction but has harmful side-effects. In the present study, three arylimidamides (AIAs) and CV were used to sterilize mice blood samples experimentally contaminated with bloodstream trypomastigotes (BT) of Trypanosoma cruzi, at non hemolytic doses. All AIAs were not toxic to mouse blood cells until the highest tested concentration (96 µM). The previous treatment of BT with the AIAs impaired the infection establishment of cardiac cell cultures. In vivo assays showed that pre-incubation of mouse blood samples with the AIAs and CV (96 µM) significantly suppressed the parasitemia peak, but only the AIA DB1831 gave ≥90% animal survival, while vehicle treated samples reached 0%. Our findings support further studies regarding the potential use of AIAs for blood bank purposes.

Worldwide Control and Management of Chagas Disease in a New Era of Globalization: a Close Look at Congenital Trypanosoma cruzi Infection

Population movements have turned Chagas disease (CD) into a global public health problem. Despite the successful implementation of subregional initiatives to control vectorial and transfusional Trypanosoma cruzi transmission in Latin American settings where the disease is endemic, congenital CD (cCD) remains a significant challenge. In countries where the disease is not endemic, vertical transmission plays a key role in CD expansion and is the main focus of its control. Although several health organizations provide general protocols for cCD control, its management in each geopolitical region depends on local authorities, which has resulted in a multitude of approaches. The aims of this review are to (i) describe the current global situation in CD management, with emphasis on congenital infection, and (ii) summarize the spectrum of available strategies, both official and unofficial, for cCD prevention and control in countries of endemicity and nonendemicity. From an economic point of view, the early detection and treatment of cCD are cost-effective. However, in countries where the disease is not endemic, national health policies for cCD control are nonexistent, and official regional protocols are scarce and restricted to Europe. Countries of endemicity have more protocols in place, but the implementation of diagnostic methods is hampered by economic constraints. Moreover, most protocols in both countries where the disease is endemic and those where it is not endemic have yet to incorporate recently developed technologies. The wide methodological diversity in cCD diagnostic algorithms reflects the lack of a consensus. This review may represent a first step toward the development of a common strategy, which will require the collaboration of health organizations, governments, and experts in the field.