Ralph Huits

Ospedale Sacro Cuore-Don Calabria · Infectious Tropical Diseases and Microbiology

Problem/condition: During 2012-2021, the volume of international travel reached record highs and lows. This period also was marked by the emergence or large outbreaks of multiple infectious diseases (e.g., Zika virus, yellow fever, and COVID-19). Over time, the growing ease and increased frequency of travel has resulted in the unprecedented global...

Background: Dengue virus is a flavivirus transmitted by Aedes mosquitoes and is an important cause of illness worldwide. Data on the severity of travel-associated dengue illness are limited. Objective: To describe the epidemiology, clinical characteristics, and outcomes among international travelers with severe dengue or dengue with warning sign...

Background: The COVID-19 pandemic resulted in a sharp decline of post-travel patient encounters at the European sentinel surveillance network (EuroTravNet) of travellers' health. We report on the impact of COVID-19 on travel-related infectious diseases as recorded by EuroTravNet clinics. Methods: Travelers who presented between January 1, 2019 a...

Background Professional soccer athletes are at risk of acquiring SARS-CoV-2 when traveling or through domestic community transmission. The U.S. Major League Soccer (MLS) league uses protocol-based SARS-CoV-2 testing for identification of individuals with COVID-19. Methods Per MLS protocol, fully vaccinated players underwent SARS-CoV-2 RT-PCR testi...

Background: International travellers frequently acquire infectious diseases while travelling, yet relatively little is known about the impact and economic burden of these illnesses on travellers. We conducted a prospective exploratory costing study on adult returning travellers with falciparum malaria, dengue, chikungunya, or Zika virus. Methods:...

Background: International travellers may seek care abroad to address health problems that arise during their trip or plan healthcare outside their country of residence as medical tourists. Methods: Data were collected on travellers evaluated at GeoSentinel Network sites who reported healthcare during travel. Both unplanned and planned healthcare...

Highlight Increasing numbers of travellers returning from Cuba with dengue virus infection were reported to the GeoSentinel Network from June through September 2022, reflecting an ongoing local outbreak. This report demonstrates the importance of travellers as sentinels of arboviral outbreaks and highlights the need for early identification of trav...

Background The early epidemiology of the 2022 monkeypox epidemic in non-endemic countries differs substantially from the epidemiology previously reported from endemic countries. We aimed to describe the epidemiological and clinical characteristics among individuals with confirmed cases of monkeypox infection. Methods We descriptively analysed data...

West Nile virus (WNV) can cause asymptomatic infection in humans, result in self-limiting febrile illness, or lead to severe West Nile Neuroinvasive disease (WNND). We conducted a pilot study to compare selected biomarkers of oxidative stress in sera of viremic West Nile virus patients and asymptomatic infected blood donors to investigate their pot...

In recent decades, we have seen the emergence and re-emergence of many arthropod-transmitted viruses (arboviruses) that pose important public health challenges worldwide [...]

West Nile virus (WNV) can cause asymptomatic infection in man, result in self-limiting febrile illness, or lead to severe West Nile Neuroinvasive disease (WNND). We conducted a pilot study to compare selected biomarkers of oxidative stress in sera of viremic West Nile virus patients and asymptomatic infected blood donors to investigate their potent...

Global malaria control initiatives resulted in reduced malaria case incidence from 81 cases per 1000 population at risk in 2000 to 56 in 2019. In this period, malaria mortality rates declined from 30 deaths to 13 per 100 000 population at risk.¹ However, these encouraging trends have stagnated. Liu et al. reported that the age-standardized incidenc...

We report a case of parvovirus B19-associated transient aplastic crisis following P. falciparum malaria and post-artesunate delayed haemolysis. Concomitant parvovirus B19 infection is an established cause of exacerbation of malaria-related anaemia in endemic countries, but a rare and potentially life-threatening condition in returning travellers.

Background: Benznidazole is an effective drug in the trypanocidal treatment of acute and chronic indeterminate Chagas' disease (CD). However, adverse drug reactions (ADR) are common and frequently cause patients to discontinue treatment. Objectives: We hypothesized that antioxidant supplementation could mitigate benznidazole-induced toxicity. M...

We describe a case of Plasmodium malariae malaria in a traveler returning from the Democratic Republic of Congo to Belgium. This occurred despite successful artemether-lumefantrine treatment for Plasmodium falciparum three weeks earlier and in absence of re-exposure in an endemic area. We discuss possible explanations for this unusual observation.

We report on a Pashtun family affected by haemoglobin D-Punjab/β+-thalassemia to increase the awareness of the increasing prevalence of haemoglobinopathies among primary care physicians. We highlight the diagnostic approach of these conditions and the benefits of genetic counselling.

Background Information on human filariasis in international travelers is scarce. We describe the epidemiology, clinical presentation and outcome of these infections in a reference travel clinic over the past decades. Methods We reviewed all cases of filariasis diagnosed at the Institute of Tropical Medicine, Antwerp, Belgium, from 1994 to 2018. Di...

Background The case-fatality rate of dengue in travelers is low. Secondary dengue virus (DENV) infections are considered a risk factor for fatal outcome in endemic populations, however the impact of secondary infections on mortality in travelers has not been studied systematically. We performed a descriptive analysis of case reports of dengue fatal...

Yellow fever virus (YFV) live attenuated vaccine can, in rare cases, cause life-threatening disease, typically in patients with no previous history of severe viral illness. Autosomal recessive (AR) complete IFNAR1 deficiency was reported in one 12-yr-old patient. Here, we studied seven other previously healthy patients aged 13 to 80 yr with unexpla...

Dear Colleagues, Since its introduction in 2005, high-throughput sequencing (HTS), also called next-generation sequencing or massively parallel sequencing, has rapidly become an accessible and affordable technology in many research and public health laboratories. The benefits of HTS include whole genome sequencing, pathogen discovery, and outbreak...

Yellow fever (YF) causes high fever, liver dysfunction, renal failure, hypercoagulopathy and platelet dysfunction and can lead to shock and death with a case-fatality ratio of 20 to 50%. Yellow fever vaccination results in long-lasting protective immunity. Serious adverse events, such as yellow fever vaccine-associated neurotropic disease (YEL-AND)...

Background: Species-directed therapy of leishmaniasis has been recommended for travelers since 2014, but little is known about species distribution and treatment practices in non-endemic countries. We aimed to describe leishmaniasis cases in Belgium since species typing became available and evaluate its impact on patient management. Method: Retr...

Background. Enteric fever, caused by Salmonella enterica serovar Typhi ( S. Typhi) and Paratyphi ( S. Paratyphi), is a common travel-related illness. Limited data are available on their antimicrobial resistance (AMR) patterns among travelers. Methods. Records with a culture-confirmed diagnosis seen during or after travel from January 2007 to Decemb...

Background: Three different genotypes of chikungunya virus (CHIKV) have been classified: East/Central/South African (ECSA), West African (WA), and Asian. Previously, a rapid immunochromatographic (IC) test detecting CHIKV E1-antigen showed high sensitivity for certain ECSA-genotype viruses, but this test showed poor performance against the Asian-g...

Cutaneous leishmaniasis is the most common presentation of infection by protozoan parasites of the genus Leishmania. Patients with cutaneous leishmaniasis may have one or several disfiguring skin lesions that resemble other dermatologic diseases. Old World cutaneous leishmaniasis is a major public health problem in the World Health Organization Eas...

Background: Persistence of Zika virus (ZIKV) ribonucleic acid (RNA) in semen is common after infection. Methods: We designed a reverse-transcription polymerase chain reaction assay that targets antisense ZIKV RNA (asRNA) to assess ZIKV replication competence in ZIKV RNA-positive semen samples. Results: We detected ZIKV asRNA in semen of 9 of 1...

Background: Cutaneous leishmaniasis (CL) may be emerging among international travellers and migrants. Limited data exist on mucocutaneous leishmaniasis (MCL) in travellers. We describe the epidemiology of travel-associated CL and MCL among international travellers and immigrants over a 20-year period through descriptive analysis of GeoSentinel data...

Chikungunya virus (CHIKV), a positive-sense, single-stranded RNA virus in the family Togaviridae, is transmitted by Aedes mosquitoes. Of three known CHIKV genotypes, the Asian genotype was introduced into the Caribbean islands and rapidly spread throughout Central and South Americas. We previously found patients with symptoms compatible with chikun...

Zika Preparedness Latin American Network (ZikaPLAN) is a research consortium funded by the European Commission to address the research gaps in combating Zika and to establish a sustainable network with research capacity building in the Americas. Here we present a report on ZikaPLAN`s mid-term achievements since its initiation in October 2016 to Jun...

Background: Data on rabies post-exposure prophylaxis (PEP) and the use of human rabies immunoglobulins (HRIG) in Belgium are scarce. The main objective of this study was to evaluate the timely administration of HRIG after rabies exposure. The secondary objective was to evaluate the adequate antibody response following PEP. Methods: We reviewed all...

A traveler presented with a furuncular skin abscess and periorbital edema. A larva was surgically removed from the abscess and identified as a larva of Cordylobia rodhaini. Myiasis caused by C. rodhaini is called Lund’s fly myiasis and is only rarely reported in humans. After disinfection, the remaining lesion healed without further intervention an...

Diagnosing a patient with Zika infection is not always straightforward. Here, we aim to describe our data collected from December 2015 to December 2017 and discuss the implemented algorithm and diagnostic challenges we encountered. At the National Reference Center for Arboviruses at the Institute of Tropical Medicine, Antwerp, Belgium (ITM), a comm...

In response to the aggressive global spread of the mosquito-borne chikungunya virus (CHIKV), an accurate and accessible diagnostic tool is of high importance. CHIKV, an arthri-togenic alphavirus, comprises three genotypes: East/Central/South African (ECSA), West African (WA), and Asian. A previous rapid immunochromatographic (IC) test detecting CHI...

In response to the aggressive global spread of the mosquito-borne chikungunya virus (CHIKV), an accurate and accessible diagnostic tool is of high importance. CHIKV, an arthri-togenic alphavirus, comprises three genotypes: East/Central/South African (ECSA), West African (WA), and Asian. A previous rapid immunochromatographic (IC) test detecting CHI...

Background: The incidence rate of Zika virus (ZIKV) infection in travellers from non-endemic areas to the Americas during the ZIKV outbreak in 2016 is unknown. Methods: Belgian adults who planned to travel to South America, Central America, and the Caribbean were recruited prospectively to study the incidence and characteristics of ZIKV. Demographi...

Background: Zika virus (ZIKV) infection a concern to travellers because of potential sexual transmission and adverse pregnancy outcomes. Objective: To describe our experience in diagnosing ZIKV in travellers returning from endemic territories. Method: Travellers were evaluated for ZIKV at our clinic in a 12-month period during the outbreak, us...

Background Chikungunya virus (CHIKV) emerged in Aruba for the first time in 2014. We studied the clinical presentation of acute CHIKV infection and the contribution of serologic and molecular assays to its diagnosis. In a cohort of confirmed CHIKV cases, we analysed the frequency, duration and predictors of post-chikungunya chronic polyarthralgia (...

The structured questionnaire form, used for collection of complementary clinical data and documentation of informed consent in a follow-up telephonic survey conducted by a qualified physician, 18–24 months after the CHIKV outbreak. (DOCX)

Chikungunya virus (CHIKV), a mosquito-borne pathogen, consists of three genotypes: East/Central/South African (ECSA), West African (WA), and Asian. Although a current rapid immunochromatographic (IC) test detecting CHIKV E1-antigen showed high sensitivity to ECSA-genotype viruses, it showed poor performance against the Asian-genotype virus that is...

Objective To prospectively monitor Zika viral loads in semen from Belgian travellers with confirmed Zika virus infection, who returned from the Americas during the 2016 Zika virus epidemic. Methods We recruited symptomatic travellers consulting our clinic and we confirmed infection with either reverse-transcriptase (RT) polymerase chain reaction (...

Introduction In the field of tropical medicine and travel health, different websites exist. Their information often focuses on national guidelines either for travel or treatment advice. Information on tropical medicine is available throughout the Internet, but access requires expensive subscriptions or information may lack detail and organization....

Objectives Rapid diagnostic tests targeting virus-specific antigen could significantly enhance the diagnostic capacity for chikungunya virus infections. We evaluated the accuracy of an immunochromatographic antigen test for the diagnosis of chikungunya in a reference laboratory for arboviruses. Methods an immunochromatographic rapid test that uses...

Background Rickettsiosis is a potential life threatening infectious disease in travelers. Clinical recognition is not always straightforward, as typical manifestations such as rash and/or eschar may be absent. Definite diagnosis is based on seroconversion and therefore often delayed until the convalescent phase of disease. Case presentationIn this...

Background Rapid diagnostic test (RDT) detecting the non-structural 1 (NS1) antigen is increasingly used for dengue diagnosis in endemic and non-endemic settings, but its clinical utility has not been studied in travel clinic practice. Methods From August 2012 to July 2016, travelers returning from the tropics with fever were evaluated in the Inst...

Objective Interim guidelines to prevent sexual transmission of Zika virus (ZIKV) do not recommend diagnostic testing, because the knowledge of viral kinetics in semen after acute infection is limited. We studied the presence and duration of ZIKV in semen after onset of symptoms. Methods A prospective observational cohort study (NCT 02733796) is ong...

The epidemiology of Guillain-Barré syndrome (GBS) in tropical areas is different compared with developed countries. We investigated the epidemiology of GBS on the Caribbean island of Aruba. Data were collected retrospectively from all 36 patients hospitalized with GBS between 2003 and 2011 in Aruba. We observed a seasonal distribution of GBS cases...

Infectieziekten zijn nog steeds een van de eerste drie doodsoorzaken wereldwijd, en de eerste in ontwikkelingslanden. Voor sommige ziekten, zoals malaria, tuberculose, hepatitis C en hiv boeken we successen, voor andere is de situatie angstaanjagend zoals voor dengue, chickungunya en ebola. Door toenemend internationaal toerisme en migratie en door...

Splenomegaly is a common finding in chronic hepatitis B infection. We present the case of a man with an acute flare of chronic hepatitis B infection, where splenomegaly in absence of portal hypertension led to the diagnosis of splenic marginal zone lymphoma (SMZL) with bone marrow involvement. Adequate suppression of the hepatitis B virus (HBV) vir...

Background During a dengue outbreak on the Caribbean island Aruba, highly elevated levels of ferritin were detected in dengue virus infected patients. Ferritin is an acute-phase reactant and hyperferritinaemia is a hallmark of diseases caused by extensive immune activation, such as haemophagocytic lymphohistiocytosis. The aim of this study was to i...

A 55-year-old man presented with a painless destruction of multiple joints and neurologic deficits. He was admitted with a painless pyogenic arthritis of the right ankle. Four years earlier, he had experienced instability of the right knee after an inexplicable, progressive but painless destruction of the joint. Radiographs showed erosive changes a...

Lucio's phenomenon is a rare leprosy reaction characterised by bizarrely-shaped, purpuric skin lesions and ulceration. It occurs in diffuse lepromatous leprosy and it is mainly reported in patients from Mexico and the Caribbean. We describe the case of a 90-year-old Aruban man with recurrent leg ulcers and flexion contractures of the lower extremit...

No abstract available.

Background: Dengue virus (DENV) infection is the principal cause of arthropod-borne viral disease worldwide. In the early phase, assessment of the prognosis of dengue-related illness remains a challenge to the clinician. Methods: We evaluated 281 febrile patients, who presented at our emergency department during the 2010-2011 epidemic in Aruba,...

A 42-year-old woman presented with lowered consciousness, ataxia and ophthalmoplegia; MRI of the brain revealed abnormalities compatible with Wernicke encephalopathy (thiamine deficiency).

A case of Lemierre's syndrome is reported. Although Fusobacterium species are commonly associated with this presentation, Prevotella bivia was the causative micro-organism identified in this case. The finding that disseminated anaerobic sepsis followed primary EBV infection led to the construction of a hypothetical model of infection.

A 51-year-old man became jaundiced, after experiencing flu-like symptoms for a week. On admission anaemia, thrombocytopenia, and hepatic and renal function disorders were present. One month previously he had had sinusitis. Thrombotic thrombocytopenic purpura (TTP)/haemolitic-uraemic syndrome (HUS) was suspected, but the thrombocyte count rose spont...