Failure of artemether-lumefantrine therapy in travellers returning to Belgium with Plasmodium falciparum malaria: an observational case series with genomic analysis

BACKGROUND

Failure of artemisinin-based combination therapy is increasingly reported in patients with Plasmodium falciparum malaria in sub-Saharan Africa. We aimed to describe the clinical and genomic characteristics of recent cases of P. falciparum malaria failing artemether-lumefantrine in Belgium.

METHODS

Travel-related cases of malaria confirmed at the national reference laboratory of the Institute of Tropical Medicine, Antwerp, Belgium, were reviewed. All cases for which attending clinicians reported persistence (beyond Day 3 post-treatment initiation, i.e. early failure) or recrudescence (from Day 7 to 42, i.e. late failure) of P. falciparum parasites despite adequate drug intake were analysed. Both initial and persistent/recurrent samples were submitted to next generation sequencing to investigate resistance-conferring mutations.

RESULTS

From July 2022 to June 2023, eight P. falciparum cases of failure with artemether-lumefantrine therapy were reported (early failure = 1; late failure = 7). All travellers were returning from sub-Saharan Africa, most (6/8) after a trip to visit friends and relatives. PfKelch13 (PF3D7_1343700) mutations associated with resistance to artemisinin were found in two travellers returning from East Africa, including the validated marker R561H in the patient with early failure and the candidate marker A675V in a patient with late failure. Additional mutations were detected that could contribute to decreased susceptibility to artemisinin in another three cases, lumefantrine in six cases and proguanil in all eight participants. Various regimens were used to treat the persistent/recrudescent cases, with favourable outcome.

CONCLUSION

Within a 12-month period, we investigated eight travellers returning from sub-Saharan Africa with P. falciparum malaria and in whom artemether-lumefantrine failure was documented. Mutations conferring resistance to antimalarials were found in all analysed blood samples, especially against lumefantrine and proguanil, but also artemisinin. There is a pressing need for systematic genomic surveillance of resistance to antimalarials in international travellers with P. falciparum malaria, especially those experiencing treatment failure.

Human filariasis in travelers and migrants: a retrospective 25-year analysis at the Institute of Tropical Medicine, Antwerp, Belgium

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. Diagnosis was obtained by either parasitological methods (confirmed) or strict clinical case definitions (probable). We assessed the characteristics of cases at diagnosis and response to therapy within three to 12 months.

RESULTS

A total of 320 patients (median age: 41 years; 71% males) were diagnosed with 327 filarial infections (Wuchereria bancrofti = 6; Onchocerca volvulus = 33, Loa loa = 150, Mansonella perstans = 130; unspecified species = 8). Diagnosis was confirmed in 213/320 (67%) patients. European long-term travelers accounted for 166 patients (52%) and visitors/migrants from tropical countries for another 110 (34%). Central Africa was the likely region of acquisition for 294 (92%) patients. The number of filariasis cases decreased from 21.5/year in average in the nineties to 6.3/year in the last decade, when loiasis became predominant. Cases reported symptoms in > 80% of all filarial infections but mansonellosis (45/123 single infections; 37%). Lymphatic filariasis and onchocerciasis cases responded well to conventional therapy. However, 30% of patients with loiasis and mansonellosis experienced treatment failure (with diethylcarbamazine and levamisole-mebendazole, respectively).

CONCLUSIONS

The burden and species distribution of filariasis in travelers evolved in the past decades. Most presentations were symptomatic. Case management would benefit from more effective therapies for loiasis and mansonellosis.

Time of administration of rabies immunoglobulins and adequacy of antibody response upon post-exposure prophylaxis: a descriptive retrospective study in Belgium

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 medical records from July 2017 to June 2018 of patients seeking care at, or referred to, the Institute of Tropical Medicine and the University Hospital, Antwerp for the administration of human rabies immunoglobulins following potential rabies exposure abroad or in Belgium.A timely response was defined as starting HRIG with a delay of ≤48 h and rabies vaccination in the first 7 days after exposure.Adequate antibody response was defined as a titer of >5.0 IU/mL in case of bat-related exposure and >3.0 IU/mL in case of exposure to other animals. Titers were measured 10 days after the last PEP vaccine dose, using the rapid fluorescent focus inhibition test (RFFIT).Results: Of the 92 cases treated with HRIG, 75 were evaluated.The majority of injuries were acquired in Asia (n = 26,34%) and in Western Europe (n = 18, 24%), of which 17 in Belgium. The five most frequently recorded countries overseas were Indonesia (n = 13), Thailand (n = 7), Morocco (n = 4), Peru (n = 3) and Costa Rica (n = 3). Administration of immunoglobulins was related to injuries by dogs (36%), monkeys (25%) or bats (22%).A timely response was observed in 16 (21,33%) and in 55 (73,33%) of subjects receiving HRIG (≤48 h) or rabies vaccine (<7days) respectively. The mean time between exposure and the first administered dose of rabies vaccine and HRIG was 7.7 and 8.7 days, respectively. The mean delay for HRIG administration was 9.6 days and 6 days for abroad and inland risks, respectively.In 15 of 16 (94%) bat-related cases the antibody titer after full PEP was >5.0 IU/ml. In 38 of 47 (81%) cases related to other animals the RFFIT titer was >3.0 IU/ml. All low-responders received additional rabies injections.Conclusion: This study showed a substantial time delay between the animal-related risk and the administration of HRIG, in particular when the injury occurred abroad. More targeted communication about the risks of rabies and preventable measures may reduce this delay.Furthermore, the antibody response was inadequate in some cases following full PEP administration according to the Belgian recommendation.

Acute Schistosomiasis With a Schistosoma mattheei × Schistosoma haematobium Hybrid Species in a Cluster of 34 Travelers Infected in South Africa

Background

Diagnosis of schistosomiasis remains elusive soon after infection. We evaluated several diagnostic methods in a cluster of travelers with simultaneous freshwater exposure in South Africa.

Methods

Eosinophil count, schistosome antibody tests, stool and urine microscopy, and serum Dra1 PCR assays were performed at weeks 4–5 (early symptomatic phase), 7–8 (praziquantel treatment), and 13–14 (after treatment). Sequencing was done on serum samples from 3 patients to identify the species.

Results

Of the 34 travelers (16 adults and 18 children), 32 developed symptoms 2–6 weeks after exposure. A raised eosinophil count (&gt;750/µL) was seen in 12 of 33 at weeks 4–5, and in 22 of 34 at weeks 7–8. Schistosoma antibodies were detected in 3 of 33 at weeks 4–5 and in 12 of 34 at weeks 7–8 and weeks 13–14. The Dra1 PCR result was positive in 24 of 33 travelers at weeks 4–5, in 31 of 34 at weeks 7–8, in 25 of 34 at weeks 13–14, and at least once in all. Ova were absent in all urine and stool samples obtained. Sequencing identified Schistosoma mattheei nuclear and Schistosoma haematobium mitochondrial DNA, indicative of a hybrid species.

Conclusions

The Dra1 PCR confirmed the diagnosis in all exposed travelers at a much earlier stage than conventional tests. The causative species is probably an S. mattheei × S. haematobium hybrid.

Is systematic screening and treatment for latent tuberculosis infection in HIV patients useful in a low endemic setting?

OBJECTIVES

A decreasing incidence of tuberculosis (TB) among HIV patients has been documented in high-income settings and screening for tuberculosis is not systematically performed in many clinics (such as ours). Our objectives are to evaluate whether a same decline of incidence was seen in our Belgian tertiary center and to evaluate whether systematic screening and prophylaxis of tuberculosis should remain part of routine practice.

METHODS

Between 2005 and 2012, the annual incidence of tuberculosis among adult HIV patients was measured. The impact of demographic characteristics and CD₄ nadir on the incidence of active TB was evaluated.

RESULTS

Among the 1167 patients who entered the cohort, 42 developed active TB with a significant decrease of annual incidence from 28/1000 patient-years in 2005 to 3/1000 patient-years in 2012. Among the 42 cases, 83% were of sub-Saharan origin. Median CD4 cell count upon HIV diagnosis was significantly lower in TB cases and 60% had a nadir CD4 below 200/μl. Thirty-six percent of incident TB occurred within 14 days after HIV diagnosis.

CONCLUSION

A significant decline of TB incidence in HIV patients was observed. Incident TB occurred mainly in African patients, with low CD4 upon HIV diagnosis. A significant proportion of TB cases were discovered early in follow-up which probably reflects TB already present upon HIV diagnosis. In a low endemic setting, exclusion of active TB upon HIV diagnosis remains a priority and screening for LTBI should focus on HIV patients from high risk groups such as migrants from endemic regions, especially in patients with low CD4 nadir.

Lessons Learned From 2 Patients With Multidrug-Resistant HIV-1 Infection Successfully Treated With a Darunavir-Containing Antiretroviral Treatment Regimen

The authors describe 2 patients with life-threatening multidrug-resistant HIV-1 infection who responded very well to a treatment regimen containing darunavir and enfuvirtide. They discuss the availability of several new treatment options such as darunavir, etravirine, integrase, and CCR5 inhibitors for patients with multidrug-resistant viruses.

Is systematic screening for thyroid disorders indicated in subfertile men?

CONTEXT

Data on the prevalence of thyroid disorders in male subfertility remain scarce.

OBJECTIVE

To investigate the prevalence of thyroid dysfunction and thyroid autoimmunity in men with normal and abnormal semen characteristics.

SETTING

Tertiary referral center for reproductive medicine of the University Hospital AZ-VUB, Brussels, Belgium.

PATIENTS AND DESIGN

Two hundred and ninety-two men were stratified according to the presence of normal (group 1; n = 39) or abnormal (group 2; n = 253) semen characteristics. Thyroid function was assessed by serum thyrotropin (TSH) and free thyroxine (FT4), and thyroid peroxidase antibodies (TPO-Ab) for thyroid autoimmunity (TAI or TPO-Ab > 34 kU/l); both were correlated with semen characteristics.

MAIN OUTCOME MEASURES

Semen characteristics were determined by World Health Organisation criteria (rapid + slow motility > or = 50% and concentration > or = 20 x 10(6)) and Kruger criteria (morphology > or = 14% normal cells).

RESULTS

In group 1, the mean (+/- s.d.) age was 33 +/- 4 years; serum TSH was 1.6 (0.3-29.6) mU/l (median (range)) and FT4 was 12.2 (8.8-15.6) ng/l. In group 2, the mean age was 33 +/- 5 years, serum TSH was 1.3 (0.3-5.2) mU/l and FT4 was 12.5 (8.4-17.5) ng/l; (compared with group 1 P = 0.008 for TSH and P = 0.037 for FT4). In both groups, one patient had increased TSH (2.6% and 0.4%; P = not significant (ns)). In group 1, one patient had TAI and in group 2 twelve patients had TAI (2.6% compared with 4.7%; P = ns). FT4 was an independent determinant for semen characteristics.

CONCLUSIONS

The prevalence of thyroid dysfunction and autoimmunity is comparable between men with normal and abnormal semen characteristics. On the basis of these data, we do not advise systematic screening for thyroid disorders in subfertile men consulting a tertiary referral center for reproductive medicine.