Investigation of Tropical Eosinophilia; Assessing a Strategy Based on Geographical Area

doi:10.1053/jinf.2002.1108

Journal of Infection

Volume 46, Issue 3, April 2003, Pages 180-185

https://doi.org/10.1053/jinf.2002.1108 Get rights and content

Abstract

Objectives: Patients with eosinophilia are an important clinical problem. This study aimed to assess the most efficient manner of investigating patients with peripheral eosinophilia (eosinophil count >0.5×10⁹ ml⁻¹) presenting from the tropics.

Methods: Patients attending the Hospital for Tropical Diseases, London, from October 1997 to March 2002 for investigation of eosinophilia were identified prospectively. Laboratory, clinical and demographic data were recorded from laboratory and clinical records. An investigation set was proposed prospectively and assessed for all geographical areas (stool microscopy, strongyloides culture and serology), all of Africa (additional schistosomal serology, terminal urine microscopy and filarial serology) and West Africa (additional day-bloods for microfilaria).

Results: Data was analysed for 261 patients. At least one helminthic cause for eosinophilia was found in 64% of patients (median eosinophilia 1.2×10⁹ ml⁻¹). Seventeen per cent of patients had more than one helminth species found. Median eosinophilia increased with number of diagnoses per patient. The proposed investigation sets were validated, with high yield for all proposed tests apart from filarial serology outside West Africa, and good sensitivity.

Conclusions: Initial investigation of eosinophilia in patients presenting from the tropics may be guided by a simple investigation set depending on broad area of travel which has high sensitivity and yield. Patients frequently have more than one helminthic cause of eosinophilia.

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The investigation of eosinophilia
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Citation Excerpt :
A considerable proportion (21–33%) of travellers and migrants with eosinophilia have no symptoms.1 The most common pathogens identified in this group are intestinal helminths, schistosomes, Strongyloides and Filaria.1 Schistosomiasis and strongyloidiasis can have serious consequences, so it is important to investigate eosinophilia in returning travellers and migrants, even if it is asymptomatic.
Eosinophilia is a common problem in travellers and migrants returning from the tropics. It usually signifies an underlying helminth infection, although it is still important to bear in mind the possibility of a non-infectious cause in this group of patients. It is frequently asymptomatic, but deserves investigation to prevent significant disease in the future. The presentation of helminth infections can differ between individuals who have migrated from endemic areas – who can have heavy infections with a subacute course – and travellers, in whom acute presentations are usual. Negative tests should be repeated if they were performed within 3 months of return from the tropics. Here, we consider the most common and potentially serious causes of eosinophilia in returned travellers. The diagnosis of eosinophilia can be incidental, so we first consider when and how to investigate asymptomatic eosinophilia. We then consider the symptomatic presentation of eosinophilia, organized in syndromes that the physician is likely to encounter (fever and respiratory, gastrointestinal, genitourinary, neurological and dermatological presentations).
Eosinophilia prevalence and related factors in travel and immigrants of the network +REDIVI
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Algunas enfermedades infecciosas han adquirido más relevancia por el aumento de los movimientos poblacionales. La eosinofilia es un hallazgo frecuente en inmigrantes y en viajeros. Una de las causas más frecuentes de eosinofilia es la infección por helmintos y algunos protozoos intestinales.
El objetivo de este trabajo es describir las características epidemiológicas de los casos con eosinofilia y su asociación con la presencia de parásitos en la red de datos REDIVI.
Se trata de un estudio observacional multicéntrico prospectivo, donde se incluyen los casos diagnosticados de eosinofilia registrados en la Red cooperativa para el estudio de las infecciones importadas por viajeros e inmigrantes (+REDIVI) desde enero de 2009 hasta diciembre de 2012.
Se registraron en la red un total de 5.255 episodios durante el periodo de estudio, y la eosinofilia fue un hallazgo en el 8,1 al 31,3% de los casos (dependiendo del tipo migratorio). Fueron hombres el 60,2%, con una mediana de 31,0 años, inmigrantes el 72,4% y asintomáticos el 81,2%. Los parásitos más frecuentemente identificados fueron S. stercoralis (34,4%), Schistosoma sp. (11,0%) y uncinarias (8,6%). Existía asociación entre eosinofilia y presencia de parásitos para todos los helmintos (excepto para larva migrans cutánea). La sintomatología y la duración del viaje no determinaron significativamente la presencia de eosinofilia.
Ante una eosinofilia en una persona que ha vivido en zonas endémicas de helmintiasis es aconsejable realizar estudios dirigidos para su diagnóstico, independientemente del tipo migratorio, la duración de la estancia o la presencia de sintomatología.
The population movements during the last decades have resulted in a progressively increasing interest in certain infectious diseases. Eosinophilia is a common finding in immigrants and travellers. One of the most common causes of eosinophilia is helminth infection, and some intestinal protozoa.
The aim of this paper is to describe the epidemiological characteristics of cases with eosinophilia and its association with the presence of parasites in the REDIVI data network.
This is a multicentre prospective observational study that includes patients diagnosed with eosinophilia registered in the cooperative network for the study of infectious diseases in travellers and immigrants (+REDIVI) from January 2009 to December 2012.
A total of 5,255 episodes were recorded in the network during the study period, and eosinophilia was observed in 8.1-31.3% of cases (depending on the immigration group). There were 60.2% men, with a median age of 31 years. There were 72.4% immigrants, and 81.2% were asymptomatic. The most commonly identified parasites were S. stercoralis (34.4%), Schistosoma sp. (11.0%), and hookworm (8.6%). The relationship between eosinophilia and parasite infection was significant for all helminths (except for cutaneous larva migrans). The symptoms and duration of the journey did not significantly determine the presence of eosinophilia.
In the case of eosinophilia in a person who has lived in helminth endemic areas, it is advisable to carry out targeted studies to diagnose the infection, regardless of immigration type, length of stay, or the presence of symptoms.
Helminthic infections in returning travelers and migrants with eosinophilia: Diagnostic value of medical history, eosinophil count and IgE
2017, Travel Medicine and Infectious Disease
Eosinophilia in travelers and migrants returning from the tropics is often associated with invasive helminthic infections. Total IgE is considered a useful additional diagnostic parameter; however, both parameters are also increased in various other non-helminthic diseases.
We retrospectively evaluated travelers and migrants seen at our department between September 2007 and May 2014. Patients with an absolute eosinophil count ≥500 cells/μl were considered for further analyses.
Among 6618 returned travelers and migrants, 154 (2.3%) had a total eosinophil count ≥500 cells/μL. Of these, 71 patients (46%) were diagnosed with helminthic infection. In an additional 62 patients (40%) with eosinophilia a final diagnosis was found, including non-helminthic infections in 34 patients and non-infectious causes in 28 patients, while in 21 patients (14%) no diagnosis was made. Patients with helminthic infections had higher eosinophil counts than travelers and migrants with other diagnoses (median 981 vs. 710 cells/μl; p = 0.001), while total IgE levels (n = 70; 172 vs. 152 kU/l; p = 0.731) were similar in both groups.
Eosinophil count but not total IgE levels are associated with helminthic infections in returning travelers and migrants with eosinophilia. Our results do not support the use of total IgE to differentiate helminthic infections from other causes of eosinophilia in this population.
The changing aetiology of eosinophilia in migrants and returning travellers in the Hospital for Tropical Diseases, London 2002–2015: An observational study
2017, Journal of Infection
Citation Excerpt :
Whilst numerous microbiological and serological tests are available, untargeted testing is time-consuming, expensive and frustrating.5 Many strategies have been suggested to rationalise the approach to patients with eosinophilia, including microscopy of multiple stool samples for ova, cysts and parasites (OCP), serological screening in selected patient groups,2,6,7 screening based on geographic area of travel3,5,8,9 and even empirical treatment amongst refugee populations.2,10–13 It is important to note that many of these approaches are based on studies of unselected groups of refugees or returning travellers, and thus may not have validity for focused investigation of eosinophilia in the wider populations.
Determining the cause of eosinophilia in patients returning from the tropics continues to present a diagnostic challenge. The history, symptoms and degree of eosinophilia are often poor predictors of eventual diagnosis, but helminths are an important cause. The current British Infection Association recommendations use travel history to guide investigation of eosinophilia. However the global burden of helminth disease and travel patterns have changed over the last 3 decades and guidelines based on previous epidemiology need to be reviewed in the light of current data.
Consecutive patients presenting with, or referred for, investigation of eosinophilia were identified prospectively. Case notes, laboratory results and electronic records were reviewed for demographic and clinical data. Patients with an eosinophil count ≥0.50 × 10⁹/L were included, and grouped based on lifetime history of travel to: West Africa, elsewhere in Africa, and the rest of the world. Results were compared to published data from 1997 to 2002 collected at the same centre.
Of 410 patients who met the inclusion criteria, 407 had a documented travel history. Average yearly referrals for eosinophilia fell from 58 per year between 1997 and 2002, to 33 per year (2002–2015). The proportion of eosinophilia cases diagnosed with a parasitic cause fell from 64% to 50%, and yields for all parasitological investigations fell, the largest reduction in stool microscopy (20% yield to 9%) and day bloods for microfilariae (14% yield to 3%). Strongyloides stercoralis was the commonest diagnosis overall in our cohort, accounting for 50% of the total parasites diagnosed, and was present in 38% of patients from West Africa, 19% from rest of Africa, and 34% from rest of world; a relative increase compared to previous data. Schistosomiasis is slightly less common in those who had travelled to West Africa than the rest of Africa, and overall point prevalence has fallen from 33% (1997–2002) to 17% (2002–2015). Travellers were significantly less likely than patients who had immigrated to the UK to be diagnosed with any parasite (OR 0.54 95% CI 0.378–0.778 p = 0.0009).
A parasitic cause will still be found in half of people returning from the tropics with an eosinophilia, but we observed a fall in the overall prevalence of parasitic diagnoses when compared with the earlier data. This may, in part, be explained by the impact of control programmes on the prevalence of parasites globally, especially filarial disease. S. stercoralis now represents the majority of parasites diagnosed in our cohort from all continents. We identified significantly higher rates of strongyloidiasis in immigrants than returning travellers. Despite the falling yields of stool microscopy and filarial serology the current guidelines based on travel history remain relevant with adequate yield.

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^f1: Please address all correspondence to: C. J. M. Whitty, Consultant Physician, The Hospital for Tropical Diseases, Mortimer Market, Capper Street, London WC1E 6AU, UK. Tel.: 02072994715; Fax: 0207299 4720; E-mail address:[email protected] (C. J. M. Whitty).

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Regular ArticleInvestigation of Tropical Eosinophilia; Assessing a Strategy Based on Geographical Area

Abstract

Trans R Soc Trop Med Hyg

Inf Dis Clin North Am

Trans R Soc Trop Med Hyg

Trans R Soc Trop Med Hyg

N Eng J Med

Relationship between schistosomiasis and bladder cancer

Clin Microbiol Rev

Strongyloides in US veterans of the Vietnam and other wars

J Am Med Ass

Eosinophilia

Eosinophilia in the returning traveler

Inf Dis Clin North Am

Regular Article
Investigation of Tropical Eosinophilia; Assessing a Strategy Based on Geographical Area