Eight Giardia duodenalis genotypes (A-H) have been described to date. Genotypes A and B have been isolated from humans and a wide range of mammals; however, genotypes C-H have shown greater host specificity. Identifying G. duodenalis genotypes from cysts in faeces obtained from children attending the Instituto Colombiano de Bienestar Familiar (ICBF) day care centres and from dogs in Ibagué by PCR-RFLP targeting both the b -giardin and glutamate dehydrogenase genes. Cysts from G. duodenalis positive samples were concentrated, DNA was extracted and the b -giardin and glutamate dehydrogenase genes were analysed by PCR-RFLP. The MHOM/CO/04/G40 strain was used as positive control (this was obtained from the Grupo de Parasitología at the Instituto Nacional de Salud ). Of the total human samples, 11/23 (48%) were genotyped as A and 12/23 (52%) as B; PCR-RFLP revealed that four canine samples were genotypes C and D, these being host-specific. Only genotypes associated with human infection (AII, BIII and BIV) were found in the children and host-specific genotypes were observed in canines (C and D). No interaction could be established between animal and human transmission cycles due to the small canine sample size and as the former did not come into contact with children attending ICBF day-care centres.

COVID-19, a global pandemic causing to date more than 50 million cases and more than a million deaths, has to be controlled. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) was identified as the causative agent. Controversy about this virus origin and infectious mechanism for adapting to humans remains a matter for discussion. Among all strategies for obtaining safe and potent vaccines, approaches based on attenuated-killed virus and non-replicating RNA viral vectors are demonstrating promising results. However, specificity of viral components targeted by human antibodies so far has not been demonstrated. A consistent strategy for obtaining functional-active antigens from SARS-CoV-2 specific ligands lead us to propose and test a number of synthetic components. From hundreds of starting sequences only fifteen fulfilled the design requirements and were produced as monomer and polymer forms and immuno-chemically tested. The design was based on worldwide representative reported virus genomes. A bioinformatics scheme by conventional methods and knowledge on MHC-I and II antigen processing mechanisms and HLA haplotype-restriction was performed including sensitive and resistant human populations to virus infection. Covid-19 patients’ sera reactivity for synthetic SARS-CoV-2-designed components have proven a high recognition of specific molecules, as well as some evidence for a long-lasting humoral immune response.

Clinical trajectories following Trypanosoma cruzi infection are heterogeneous, and the determinants of post-treatment parasitological dynamics and cardiac progression remain incompletely characterized, particularly in TcI-predominant regions. This study assessed, in both the acute phase and the indeterminate chronic form, the association between TcI infection and molecular clearance kinetics, cardiac progression, and the prognostic value of early molecular response. An ambispective cohort in Colombia included patients with acute or indeterminate chronic infection followed between 2000 and 2023. Sustained clearance was defined as two consecutive negative quantitative polymerase chain reaction results obtained at separate visits. Time-to-event analyses were conducted using Kaplan–Meier curves and Cox proportional hazards models. TcI infection was consistently associated with delayed molecular clearance in both clinical presentations. Although long-term clearance was achieved in most patients, TcI infection was independently associated with a higher risk of cardiac progression. In contrast, quantitative polymerase chain reaction negativity at 12 months was associated with reduced subsequent progression risk, indicating that sustained molecular response is a clinically meaningful prognostic marker. Collectively, these findings support the incorporation of early molecular monitoring into risk-stratified follow-up strategies in TcI-predominant settings and reinforce the need for phase-specific clinical management approaches.