+
MODEL
Travel Medicine and Infectious Disease (2015) xx, 1e2
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid
EDITORIAL
Immigration, helminths and eosinophilia: A complex triad The number of international migrants has recently been estimated to be over 232 million, or 3.2% of the world population [1]. Most migrants are healthy adults but some, especially those arriving from developing countries, may have asymptomatic latent infections which could lead to chronic disease and/or long-term complications [2]. For some, mild peripheral eosinophilia may be the only clue to cryptic helminthiasis. Currently, there is no clear international consensus or specific universal management guidelines for screening newly arrived immigrants. Helminth infections are not uncommon in migrant populations. In a series of over 7000 migrants evaluated at specialized GeoSentinel clinics for specific health problems, schistosomiasis and strongyloidiasis were diagnosed in 6% and 5% of patients, respectively [3]. It is important to note that these infections may be diagnosed even in asymptomatic patients, as reported recently in a study screening asymptomatic sub-Saharan African and Latin American immigrants which found a prevalence of schistosomiasis of 5.9% in the former and an overall prevalence of strongyloidiasis (positive serology) of >55% in those presenting with peripheral eosinophilia [2]. In the article by Salas-Coronas et al. in this issue [4] investigating the etiology of eosinophilia in immigrants (mainly from sub-Saharan countries) in an area in southern Spain, a diagnosis of helminthiasis was obtained in over 75% through the implementation of a specific structured protocol. The most frequent diagnoses were schistosomiasis, strongyloidiasis and hookworm infection, and multiple infections were common. Eosinophilia resolved in over 90% of the patients treated empirically with ivermectin and albendazole (and praziquantel if from sub-Saharan Africa or a Latin American country endemic for S. mansoni) when an etiological diagnosis was not obtained after following the complete protocol. Of note, nearly a third of patients were lost to follow-up during the study period. These studies illustrate several of the challenges encountered when investigating helminth infections and/ or eosinophilia, especially in asymptomatic immigrants. Although studies on cost-effectiveness are scarce, some
experts argue administration of empirical treatment with albendazole (and praziquantel if from sub-Saharan Africa) to immigrants at risk for helminthiasis and/or with eosinophilia may be of use. Further studies could then be requested if symptoms and eosinophilia do not resolve. One study investigating the strategy of administering albendazole to all immigrants at risk for intestinal parasites found this to be more cost-effective than universal screening and treatment of those with positive stool examinations [5]. However, in clinical practice additional problems may be encountered. For health professionals not familiar with imported infections, identifying specific risk factors may be complex and this could entail a risk of not adequately treating occult infections which could either be potentially life-threatening, such as strongyloidiasis in an immunocompromised host, or could lead to serious complications, such as chronic schistosomiasis-associated genitourinary neoplasia. Regarding diagnosis, interpretation of indirect methods for detecting certain helminth infections, mainly serologies for nematodes such as Strongyloides sp., may not be straightforward, especially in cases of polyparasitism, with multiple infections in one individual. These infections would often not be effectively treated with only one drug. In some cases, empirical antiparasitic treatment may even pose a hypothetical risk for the individual, for example, if albendazole is administered to patients with undiagnosed neurocysticercosis. Patients for whom empirical treatment may be an option should therefore be carefully evaluated. Thus, immigrants with suspected helminthiasis and/or eosinophilia should be managed following specific protocols based on geographical risk of exposure ideally at specialized or referral centres to optimize resources and ensure continuity of care and improved follow-up. A systematic screening protocol could be applied for asymptomatic patients, including stool analysis for parasites (if recent migration or eosinophilia), Strongyloides sp. serology (and Schistosoma spp. serology in sub-Saharan Africans), as well as serologies for transmissible diseases
http://dx.doi.org/10.1016/j.tmaid.2015.06.001 1477-8939/ª 2015 Published by Elsevier Ltd. Please cite this article in press as: Norman FF, Lo ´pez-Ve ´lez R, Immigration, helminths and eosinophilia: A complex triad, Travel Medicine and Infectious Disease (2015), http://dx.doi.org/10.1016/j.tmaid.2015.06.001
+
MODEL
2 such as HIV, hepatitis B and C and syphilis Trypanosoma cruzi in Latin American migrants, and testing for latent tuberculosis [2]. Guided screening and additional testing based on symptoms or specific exposures may be performed for other helminthiasis, such as filariases, especially if eosinophilia is detected. Finally some of the specific anti-parasitic therapies may not be easily accessible for all patients, especially irregular migrants, and administration of these treatments may be channelled through reference centres. Timely detection and treatment of imported parasitic infections may help decrease the morbidity associated with these neglected tropical diseases.
Conflict of interest None.
References [1] International Organization for Migration. Global migration trends: an overview. December 2014. http://www.iomvienna. at/sites/default/files/Global_Migration_Trends_PDF_ FinalVH_with%20References.pdf [accessed 20.04.15]. [2] Monge-Maillo B, Lo ´pez-Ve ´lez R, Norman FF, Ferrere-Gonza ´lez F, Martı´nez-Pe ´rez A, Pe ´rez-Molina JA. Screening of imported
Editorial infectious diseases among asymptomatic Sub-Saharan African and Latin American immigrants: a public health challenge. Am J Trop Med Hyg 2015;92(4):848e56. [3] McCarthy AE, Weld LH, Barnett ED, So H, Coyle C, Greenaway C, et al. Spectrum of illness in international migrants seen at GeoSentinel clinics in 1997-2009, part 2: migrants resettled internationally and evaluated for specific health concerns. Clin Infect Dis 2013;56(7):925e33. [4] Salas-Coronas J, Cabezas-Ferna ´ndez MT, Va ´zquez-Villegas J, Soriano-Pe ´rez MJ, Lozano-Serrano AB, Cabeza-Barrera MI, et al. Etiology of eosinophilia in immigrants in Southern Spain. Results after the application of the eosinophilia diagnosis and treatment protocol. Trav Med Infect Dis 2015. [5] Muennig P, Pallin D, Sell RL, Chan MS. The cost effectiveness of strategies for the treatment of intestinal parasites in immigrants. N Engl J Med 1999;340(10):773e9.
Francesca F. Norman Rogelio Lo ´pez-Ve ´lez* National Referral Unit for Tropical Diseases, Infectious Diseases Department, Ramo´n y Cajal University Hospital, IRYCIS, Madrid, Spain *Corresponding author. E-mail address: [email protected] (R. Lo ´pez-Ve ´lez) 4 June 2015
Please cite this article in press as: Norman FF, Lo ´pez-Ve ´lez R, Immigration, helminths and eosinophilia: A complex triad, Travel Medicine and Infectious Disease (2015), http://dx.doi.org/10.1016/j.tmaid.2015.06.001
MODEL
Travel Medicine and Infectious Disease (2015) xx, 1e2
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevierhealth.com/journals/tmid
EDITORIAL
Immigration, helminths and eosinophilia: A complex triad The number of international migrants has recently been estimated to be over 232 million, or 3.2% of the world population [1]. Most migrants are healthy adults but some, especially those arriving from developing countries, may have asymptomatic latent infections which could lead to chronic disease and/or long-term complications [2]. For some, mild peripheral eosinophilia may be the only clue to cryptic helminthiasis. Currently, there is no clear international consensus or specific universal management guidelines for screening newly arrived immigrants. Helminth infections are not uncommon in migrant populations. In a series of over 7000 migrants evaluated at specialized GeoSentinel clinics for specific health problems, schistosomiasis and strongyloidiasis were diagnosed in 6% and 5% of patients, respectively [3]. It is important to note that these infections may be diagnosed even in asymptomatic patients, as reported recently in a study screening asymptomatic sub-Saharan African and Latin American immigrants which found a prevalence of schistosomiasis of 5.9% in the former and an overall prevalence of strongyloidiasis (positive serology) of >55% in those presenting with peripheral eosinophilia [2]. In the article by Salas-Coronas et al. in this issue [4] investigating the etiology of eosinophilia in immigrants (mainly from sub-Saharan countries) in an area in southern Spain, a diagnosis of helminthiasis was obtained in over 75% through the implementation of a specific structured protocol. The most frequent diagnoses were schistosomiasis, strongyloidiasis and hookworm infection, and multiple infections were common. Eosinophilia resolved in over 90% of the patients treated empirically with ivermectin and albendazole (and praziquantel if from sub-Saharan Africa or a Latin American country endemic for S. mansoni) when an etiological diagnosis was not obtained after following the complete protocol. Of note, nearly a third of patients were lost to follow-up during the study period. These studies illustrate several of the challenges encountered when investigating helminth infections and/ or eosinophilia, especially in asymptomatic immigrants. Although studies on cost-effectiveness are scarce, some
experts argue administration of empirical treatment with albendazole (and praziquantel if from sub-Saharan Africa) to immigrants at risk for helminthiasis and/or with eosinophilia may be of use. Further studies could then be requested if symptoms and eosinophilia do not resolve. One study investigating the strategy of administering albendazole to all immigrants at risk for intestinal parasites found this to be more cost-effective than universal screening and treatment of those with positive stool examinations [5]. However, in clinical practice additional problems may be encountered. For health professionals not familiar with imported infections, identifying specific risk factors may be complex and this could entail a risk of not adequately treating occult infections which could either be potentially life-threatening, such as strongyloidiasis in an immunocompromised host, or could lead to serious complications, such as chronic schistosomiasis-associated genitourinary neoplasia. Regarding diagnosis, interpretation of indirect methods for detecting certain helminth infections, mainly serologies for nematodes such as Strongyloides sp., may not be straightforward, especially in cases of polyparasitism, with multiple infections in one individual. These infections would often not be effectively treated with only one drug. In some cases, empirical antiparasitic treatment may even pose a hypothetical risk for the individual, for example, if albendazole is administered to patients with undiagnosed neurocysticercosis. Patients for whom empirical treatment may be an option should therefore be carefully evaluated. Thus, immigrants with suspected helminthiasis and/or eosinophilia should be managed following specific protocols based on geographical risk of exposure ideally at specialized or referral centres to optimize resources and ensure continuity of care and improved follow-up. A systematic screening protocol could be applied for asymptomatic patients, including stool analysis for parasites (if recent migration or eosinophilia), Strongyloides sp. serology (and Schistosoma spp. serology in sub-Saharan Africans), as well as serologies for transmissible diseases
http://dx.doi.org/10.1016/j.tmaid.2015.06.001 1477-8939/ª 2015 Published by Elsevier Ltd. Please cite this article in press as: Norman FF, Lo ´pez-Ve ´lez R, Immigration, helminths and eosinophilia: A complex triad, Travel Medicine and Infectious Disease (2015), http://dx.doi.org/10.1016/j.tmaid.2015.06.001
+
MODEL
2 such as HIV, hepatitis B and C and syphilis Trypanosoma cruzi in Latin American migrants, and testing for latent tuberculosis [2]. Guided screening and additional testing based on symptoms or specific exposures may be performed for other helminthiasis, such as filariases, especially if eosinophilia is detected. Finally some of the specific anti-parasitic therapies may not be easily accessible for all patients, especially irregular migrants, and administration of these treatments may be channelled through reference centres. Timely detection and treatment of imported parasitic infections may help decrease the morbidity associated with these neglected tropical diseases.
Conflict of interest None.
References [1] International Organization for Migration. Global migration trends: an overview. December 2014. http://www.iomvienna. at/sites/default/files/Global_Migration_Trends_PDF_ FinalVH_with%20References.pdf [accessed 20.04.15]. [2] Monge-Maillo B, Lo ´pez-Ve ´lez R, Norman FF, Ferrere-Gonza ´lez F, Martı´nez-Pe ´rez A, Pe ´rez-Molina JA. Screening of imported
Editorial infectious diseases among asymptomatic Sub-Saharan African and Latin American immigrants: a public health challenge. Am J Trop Med Hyg 2015;92(4):848e56. [3] McCarthy AE, Weld LH, Barnett ED, So H, Coyle C, Greenaway C, et al. Spectrum of illness in international migrants seen at GeoSentinel clinics in 1997-2009, part 2: migrants resettled internationally and evaluated for specific health concerns. Clin Infect Dis 2013;56(7):925e33. [4] Salas-Coronas J, Cabezas-Ferna ´ndez MT, Va ´zquez-Villegas J, Soriano-Pe ´rez MJ, Lozano-Serrano AB, Cabeza-Barrera MI, et al. Etiology of eosinophilia in immigrants in Southern Spain. Results after the application of the eosinophilia diagnosis and treatment protocol. Trav Med Infect Dis 2015. [5] Muennig P, Pallin D, Sell RL, Chan MS. The cost effectiveness of strategies for the treatment of intestinal parasites in immigrants. N Engl J Med 1999;340(10):773e9.
Francesca F. Norman Rogelio Lo ´pez-Ve ´lez* National Referral Unit for Tropical Diseases, Infectious Diseases Department, Ramo´n y Cajal University Hospital, IRYCIS, Madrid, Spain *Corresponding author. E-mail address: [email protected] (R. Lo ´pez-Ve ´lez) 4 June 2015
Please cite this article in press as: Norman FF, Lo ´pez-Ve ´lez R, Immigration, helminths and eosinophilia: A complex triad, Travel Medicine and Infectious Disease (2015), http://dx.doi.org/10.1016/j.tmaid.2015.06.001
