Conference Agenda

Introduction: Intestinal parasitic infections are common among in travelers from tropical countries. We present a clinical case series of unusual intestinal protozoa and helminths diagnosed and treated at the University Hospital Bulovka in Prague, Czech Republic between 2017 and 2023.

Case 1: A 36-year-old female visited South America from October 2019 to March 2020. She suffered from watery diarrhea without fever since January 2020. Parasitological stool Examinatio (flotation with ZnSO₄) revealed oocysts of Sarcocystis sp. Molecular analysis confirmed Sarcocystis hominis, and treatment with co-trimoxazole was successful.

Case 2: A 29-year-old man worked in Kenya from September 2021 to May 2023. He developed chronic watery diarrhea without fever after visiting Uganda in March 2023. In June 2023, investigation revealed significant eosinophilia (3,070/μl) and presence of Trichostrongylus sp. eggs in stool (flotation with ZnSO₄). After treatment with albendazole, both diarrhea and eosinophilia resolved. Molecular analysis of samples is ongoing.

Case 3: Hookworm infection is common among travelers. A case of Ancylostoma ceylanicum was diagnosed at female traveler returning from Southeast Asia in 2017.

Conclusion: Routine multiplex PCR diagnostic kits for intestinal parasitic infections do not detect unusual parasites. Therefore, stool microscopy performed by experienced parasitologist is essential for diagnostics of these infections.

The zoonotic hookworm Ancylostoma ceylanicum is the second commonest hookworm infecting humans in the Asia Pacific. However, except from anecdotal cases, reports of this hookworm in the Americas have been limited. This is most likely due to the predominant use of microscopy techniques for diagnosis, which has prevented the identification of hookworms to the species level. Recent reports, which used molecular techniques, suggested A. ceylanicum infection in humans in South America in the early 2000’s. However, there was no recent information about zoonotic hookworm species on the continent. Recently, we conducted a survey of dogs and coyotes on the island of Grenada and Costa Rica using a molecular approach and revealed the presence of A. ceylanicum. We also reviewed the current state of knowledge of A. ceylanicum in the Americas and propose that this hookworm is much more widespread in this part of the world than previously assumed. Future epidemiological studies should assess the distribution, prevalence, transmission patterns and impact of A. ceylanicum infection in humans and animals in the Americas using molecular tools, in order to critically evaluate the need for the prevention and control of ancylostomiasis in a One Health context.

Recently, a review was conducted to establish the prevalence and distribution of dirofilariasis in India and Sri Lanka. Current evidence suggests that D. repens is prevalent in dogs (35.8%) and humans in India and Sri Lanka, but D. immitis is reported in dogs in India (9.7%), but, surprisingly, has not yet been reported in Sri Lanka. This apparent difference could be due to a lack studies in some regions, the presence/lack of vectors in geographic regions and/or the use of inaccurate methods for diagnosis. Our work also identified that there are a number of other Dirofilaria species and taxa of importance in animals, and emphasised the importance of zoonotic dirofilariasis, and the need for accurate diagnosis using molecular (DNA-based) methods. Interestingly, recent reports suggest that the Hong Kong genotype of Dirofilaria sp. might be more prevalent in the Asia-Pacific than previously assumed, and there is evidence of its potential to spread. Indeed, there is evidence of their occurrence of human dirofilariasis in non-endemic countries, such as Australia. Clearly, there is a need to investigate the epidemiology of dirofilariasis in animals and humans using genetic and genomic methods to aid in the prevention and control of zoonotic disease.