Schistosoma and Strongyloides screening in migrants initiating HIV Care in Canada: a cross sectional study

Abstract

Background: Following migration from Schistosoma and Strongyloides endemic to non-endemic regions, people remain at high risk for adverse sequelae from these chronic infections. HIV co-infected persons are particularly vulnerable to the serious and potentially fatal consequences of untreated helminth infection. While general screening guidelines exist for parasitic infection screening in immigrant populations, they remain silent on HIV positive populations. This study assessed the seroprevalence, epidemiology and laboratory characteristics of these two parasitic infections in a non-endemic setting in an immigrant/refugee HIV positive community. Methods: Between February 2015 and 2018 individuals born outside of Canada receiving care at the centralized HIV clinic serving southern Alberta, Canada were screened by serology and direct stool analysis for schistosomiasis and strongyloidiasis. Canadian born persons with travel-based exposure risk factors were also screened. Epidemiologic and laboratory values were analyzed using bivariate logistic regression. We assessed the screening utility of serology, direct stool analysis, eosinophilia and hematuria. Results: 253 HIV positive participants were screened. The prevalence of positive serology for Schistosoma and Strongyloides was 19.9 and 4.4%, respectively. Age between 40 and 50 years (OR 2.50, 95% CI 1.13-5.50), refugee status (3.55, 1.72-7.33), country of origin within Africa (6.15, 2.44-18.60), eosinophilia (3.56, 1.25-10.16) and CD4 count < 200 cells/mm 3 (2.46, 1.02-5.92) were associated with positive Schistosoma serology. Eosinophilia (11.31, 2.03-58.94) was associated with positive Strongyloides serology. No Schistosoma or Strongyloides parasites were identified by direct stool microscopy. Eosinophilia had poor sensitivity for identification of positive serology. Hematuria was not associated with positive Schistosoma serology. Conclusion: Positive Schistosoma and Strongyloides serology was common in this migrant HIV positive population receiving HIV care in Southern Alberta. This supports the value of routine parasitic screening as part of standard HIV care in non-endemic areas. Given the high morbidity and mortality in this relatively immunosuppressed population, especially for Strongyloides infection, screening should include both serologic and direct parasitological tests. Eosinophilia and hematuria should not be used for Schistosoma and Strongyloides serologic screening in HIV positive migrants in non-endemic settings.

Clinical Spectrum of Schistosomiasis: An Update

“…A recent meta-analysis estimated a seroprevalence in immigrants from endemic areas and living in nonendemic areas at approximately 18%, with immigrants from sub-Saharan Africa having the highest prevalence (approximately 24%) [ 36 ]. The group of HIV + immigrants showed figures over 20% [ 37 ], and that of unaccompanied immigrant minors showed figures of approximately 16% [ 38 ]. In addition, in the immigrant group from endemic areas, approximately 40% of diagnosed infections occur in asymptomatic patients [ 8 ], which can cause a diagnostic delay [ 39 ] and sometimes has serious consequences [ 40 ].…”

“…The species most frequently implicated at this level is S. haematobium [ 37 ]. This is because S. haematobium , unlike other human-infecting schistosome species, mainly migrates to the veins surrounding the bladder (the vesicle venous plexus), thus causing urinary schistosomiasis [ 38 ].…”

A Machine Learning Model for Evaluating Imported Disease Screening Strategies in Immigrant Populations

“…2 This is a group with a high prevalence of infectious diseases, constituting a real public health problem for recipient countries. [3][4][5][6][7][8][9][10][11][12] To address this problem, several international organizations (European Center for Disease Prevention and Control; Migrant Health Assessment Sub-committee of Health Protection Surveillance Centre Scientific Advisory Committee. Infectious disease assessment for migrants 2015; The Committee to Advise on Tropical Medicine and Travel [CATMAT]) [13][14][15][16] have postulated the need for institutional screening programs that would contribute to early diagnosis and treatment of these pathologies.…”

“…Infectious disease assessment for migrants 2015; The Committee to Advise on Tropical Medicine and Travel [CATMAT]) [13][14][15][16] have postulated the need for institutional screening programs that would contribute to early diagnosis and treatment of these pathologies. However, these recommendations have been made from estimates of previous epidemiological studies or have been based on the prevalence of different diseases in the country of origin, [3][4][5][6][7][8][9][10][11][12][13] which has often not been updated or showed contradictory results. Previous studies performed in countries of arrival showed variable prevalences of the different imported diseases.…”

“…However, Perez-Molina and others 3 found 5.8% of positive patients during a screening with serology (ELISA) for Schistosoma and 56% for Strongyloides during the same screening. On the contrary, McLellan et al 9 performed the same type of screening in 253 HIV-positive patients but the prevalence of positive serology for Schistosoma and Strongyloides was 19.9 and 4.4%, respectively. Regarding malaria, previous studies 10 carried out in Italy found that only 15% of malaria appears in the immigrant population compared with more than 20% found in a similar Spanish study.…”