Overcoming challenges in the diagnosis and treatment of parasitic infectious diseases in migrants

ABSTRACT

Introduction: Recent increases in population movements have created novel health challenges in many areas of the World, and health policies have been adapted accordingly in several countries. However, screening guidelines for infectious diseases are not standardized and generally do not include comprehensive screening for parasitic infections.

Areas covered: Malaria, Chagas disease, leishmaniasis, amebiasis, filariases, strongyloidiasis, and schistosomiasis are reviewed, focusing on the challenges posed for their diagnosis and management in vulnerable populations such as migrants. The methodology included literature searches in public databases such as PubMed.gov and Google Scholar and search of the US National Library of Medicine online database of privately and publicly funded clinical studies (ClinicalTrials.gov) until November 2019.

Expert opinion: Parasitic infections which may remain asymptomatic for prolonged periods, leading to chronic infection and complications, and/or may be transmitted in non-endemic areas are ideal candidates for screening. Proposed strategies to improve diagnosis in vulnerable groups such as migrants include facilitating access to healthcare in a multi-dimensional manner considering location, individual characteristics, and timing. Limitations and availability of specific diagnostic techniques should be addressed and focus on drug and vaccine development for these neglected infections should be prioritized through collaborative initiatives with public disclosure of results.

KEYWORDS:

• Malaria
• Chagas disease
• strongyloidiasis
• migrant
• screening

Article highlights

• Malaria is one of the most important parasitic infections affecting humans and screening of migrants may enable the early detection of mild or asymptomatic infections with improved outcomes. Non-vectorial modes of transmission in non-endemic areas are possible (such as through organ transplantation from an infected donor) and surveillance and control should include strategies to prevent transmission via these routes.

• Chagas disease is a neglected tropical disease causing a considerable burden of disease even in non-endemic countries. Underdiagnosis is frequent and available drugs are not associated with high efficacy in the chronic stage of the disease (the most frequent form in adult migrants) and have a high rate of adverse effects. Improvements in screening campaigns and development of new drugs, formulations, and ultimately a vaccine remain a priority.

• Specific protocols for screening migrants for leishmaniasis are unavailable and recognition of the disease with its varied presentation and subsequent management may be complex.

• All infections caused by Entamoeba histolytica even in asymptomatic carriers should be treated to prevent development of invasive disease and reduce transmission, and household contacts should be screened.

• Strongyloidiasis, and the Strongyloides hyperinfection syndrome which occurs more frequently in immunosuppressed patients may be considered emerging diseases. Oral therapy for uncomplicated cases is effective but alternative routes for administration (such as the rectal or subcutaneous administration of ivermectin) when the oral route may not be available need to be researched further. Investment in immunotherapeutic control strategies to prevent strongyloidiasis may be justified given the burden of the disease worldwide.

• Early and correct diagnosis of imported filariases in migrants may require a high index of suspicion. Management may be complex requiring specific expertise and access to antiparasitic drugs administered following specific protocols for these infections.

• Schistosomiasis in migrants may lead to serious complications if untreated. Adequate surveillance of imported infections is necessary as autochthonous schistosomiasis may occur following transmission of imported infections in non-endemic areas where competent intermediate hosts exist.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This work was supported by the Red de Investigación Colaborativa en Enfermedades Tropicales (RICET) ISCIII project ‘RD16/0027/0020’.