Update on the major imported helminth infections in travelers and migrants

Description of the Serological Response After Treatment of Chronic Imported Schistosomiasis

BACKGROUND

Chronic schistosomiasis can lead to significant morbidity. Serology is highly sensitive; however, its role in assessing treatment response is controversial. This study aimed to analyze serological values following treatment of chronic imported schistosomiasis.

METHODS

A retrospective observational study was performed including patients treated for chronic imported schistosomiasis from 2018 to 2022 who had at least one serological result at baseline and during follow-up. Demographic, clinical, and laboratory data were evaluated. Generalized estimating equation (GEE) models and Kaplan-Meier curves were used to analyze the evolution of serological values.

RESULTS

Of the 83 patients included, 72 (86.7%) were male, and the median age was 26 years (IQR 22-83). Most patients, 76 (91.6%), were migrants from sub-Saharan Africa. While 24 cases (28.9%) presented with urinary symptoms, the majority (59; 71.1%) were asymptomatic. Schistosoma haematobium eggs were observed in five cases (6.2%). Eosinophilia was present in 34 participants (40.9%). All patients had an initial positive Schistosoma ELISA serology, median ODI 2.3 (IQR 1.5-4.4); the indirect hemagglutination (IHA) test was positive/indeterminate in 34 cases (43.1%). Following treatment with praziquantel, serology values significantly decreased: -0.04 (IC95% -0.073, -0.0021) and -5.73 (IC95% -9.92, -1.53) units per month for ELISA and IHA, respectively. A quarter of patients (25%) had negative ELISA results 63 weeks after treatment. All symptomatic cases were clinically cured.

CONCLUSIONS

Serial serological determinations could be helpful for monitoring chronic schistosomiasis in non-endemic regions. The ideal timing for these follow-up tests is yet to be determined. Further research is needed to determine the factors that influence a negative result during follow-up.

Molecular diagnosis of intestinal protozoa in young adults and their pets in Colombia, South America

Intestinal parasitic infections have been considered a relevant public health problem due to the increased incidence worldwide. In developing countries, diarrhea and gastrointestinal symptoms cause impaired work capacity in adults and delayed rate growth in children. Enteric infections of unknown etiology can often lead to misdiagnosis, increased transmission, and morbidity. The aim of this study was to determine the prevalence of intestinal parasites in a young adult population and their pets. Stool samples from 139 university students and 44 companion animals were subjected to microscopy diagnosis using wet mounts, concentration by zinc sulphate flotation and staining techniques (Kinyoun and trichrome stain). Molecular diagnosis of protozoa was also performed by conventional PCR. The mean age was 24 years, 54% individuals were female, 46% were men, and 66% had at least one pet. The overall prevalence for at least one parasite was 74.8% and the rate of polyparasitism was 37.5%. Eighty-three patients (59.7%) were positive for Blastocystis spp., followed by Cryptosporidium spp. 24.5%, Endolimax nana 13.6%, Entamoeba dispar/E. moshkovskii 7.8% and Giardia intestinalis 1.4%. Molecular diagnosis substantially improved Cryptosporidium spp. and Blastocystis spp. detection and allowed to distinguish E. histolytica from commensals in the Entamoeba complex. Student's pets were also examined for parasitism. Samples from 27 dogs, 15 cats, one rabbit and one hen were analyzed, and parasites were detected in 30 (68.2%) as follows: Cryptosporidium spp. (24) Giardia spp. (4), hookworm (3), Endolimax nana (2) and Toxoplasma gondii (1). Overall, university students showed high prevalence of parasitism and polyparasitism suggesting exposure to parasite infected animals and contaminated environments. Cryptosporidium spp. was the predominant pathogen in human and domestic animals, and it was only detected by PCR, pointing out the need for sensitive tests in diagnosis and surveillance. Control strategies to prevent the effects of parasitic infections in young population should consider pets as reservoirs and transmission source.

Clinical Spectrum of Schistosomiasis: An Update

Schistosomiasis is a helminthic infection and one of the neglected tropical diseases (NTDs). It is caused by blood flukes of the genus Schistosoma. It is an important public health problem, particularly in poverty-stricken areas, especially those within the tropics and subtropics. It is estimated that at least 236 million people worldwide are infected, 90% of them in sub-Saharan Africa, and that this disease causes approximately 300,000 deaths annually. The clinical manifestations are varied and affect practically all organs. There are substantial differences in the clinical presentation, depending on the phase and clinical form of schistosomiasis in which it occurs. Schistosomiasis can remain undiagnosed for a long period of time, with secondary clinical lesion. Here, we review the clinical profile of schistosomiasis. This information may aid in the development of more efficacious treatments and improved disease prognosis.