Risk factors for imported fatal Plasmodium falciparum malaria, France, 1996-2003

New guidelines reduce the risk of hospitalization for adult patients with uncomplicated Plasmodium falciparum malaria: An observational, multicenter, retrospective French study

OBJECTIVES

We aimed to evaluate the impact of malaria declaration year (before or after 2017) on the frequency of hospitalization in metropolitan France of patients with uncomplicated non-vomiting P.falciparum malaria.

PATIENTS AND METHODS

An observational, multicenter, retrospective study was carried out, using the database from the French National Reference Centre for Malaria. Descriptive analysis and multivariate analysis by logistic regression were performed using the multiple imputation by chained equation method to handle missing data.

RESULTS

More than 2000 (2184) uncomplicated non-vomiting P.falciparum malaria cases were recorded. Our multivariate analysis showed an association between the year 2018 and reduced risk of hospitalization (OR: 0.89; 95% CI: 0.81-0.97).

CONCLUSION

Compared to 2016, during 2018 we observed a trend toward ambulatory care for patients presenting with uncomplicated non-vomiting P.falciparum malaria.

Evidence of malarial chemoprophylaxis among travellers who died from malaria: a systematic review and meta-analysis

BACKGROUND

Chemoprophylaxis is a prevention method for malaria during travel in malaria-endemic countries. This study aimed to collate and synthesize the evidence of malarial chemoprophylaxis among malaria death cases.

METHODS

Studies documenting malarial chemoprophylaxis related to malaria deaths were searched in PubMed, Scopus, MEDLINE, Embase, and CENTRAL until 3 July 2022. The pooled proportion of malarial chemoprophylaxis among death cases was synthesized using logit transformation and back transformation to a proportion performed using generalized linear mixed models. The pooled log odds ratio (log-OR) with a 95% confidence interval (CI) of malarial chemoprophylaxis in death cases compared to survivors were synthesized.

RESULTS

Fifty-eight studies were included in the systematic review and the meta-analysis. Of 602 pooled malaria death cases, the number of patients who took chemoprophylaxis was 187 (30%) (95% CI 22-40, P < 0.01, 58 studies), and those who took adequate chemoprophylaxis were 24 (5%) (95% CI 2-13, P < 0.01, 42 studies). A comparable log-OR of underwent chemoprophylaxis was observed between malaria death cases and survivors (P = 0.94, pooled log-OR: - 0.02, 95% CI - 0.46-0.42, I2: 0%, 17 studies). Similarly, a comparable log-OR of adequate chemoprophylaxis was identified between malaria death cases and survivors (P = 0.15, pooled log-OR: 0.83, 95% CI - 0.30-1.97, I2: 47.08%, 11 studies).

CONCLUSIONS

Among the studies where malarial chemoprophylaxis was reported, approximately 30% of malaria death cases had taken such prophylaxis. Notably, only 5% of these cases adhered fully or adequately to the recommended chemoprophylactic regimen. However, the analysis did not reveal a significant difference in the odds of malarial chemoprophylaxis between malaria death cases and survivors.

Epidemiological and clinical characteristics of imported falciparum malaria in the Republic of North Macedonia : A 13-year experience

BACKGROUND

Plasmodium falciparum is the leading cause of imported malaria and the most common cause of death in returning travellers.

AIM

To identify the main epidemiological and clinical characteristics of patients with imported falciparum malaria in the Republic of North Macedonia.

MATERIAL AND METHODS

Retrospectively analyzed were the epidemiological and clinical features of 34 patients with imported falciparum malaria who were diagnosed and treated at the university clinic for infectious diseases and febrile conditions in Skopje from 2010 to 2022. Malaria diagnosis was based on the microscopic detection of parasites in thick and thin blood smears.

RESULTS

All patients were male, with a median age of 36 years and a range of 22-60 years. Of the patients 33 (97.1%) acquired the disease in Sub-Saharan Africa. All patients except one stayed in endemic regions for work/business purposes. Chemoprophylaxis was completely applied in 4 (11.8%) patients. The median time of onset between the symptoms and diagnosis was 4 days, with a range of 1-12 days. Prevailing clinical manifestations were fever, chills, and splenomegaly in 100%, 94%, and 68% of patients, respectively. Severe malaria was noticed in 8 (23.5%) patients. In 5 (14.7%) patients the initial parasitemia was higher than 5%. On admission, thrombocytopenia, hyperbilirubinemia, and elevated alanine aminotransferase were registered in 94%, 58%, and 62% of patients, respectively. Out of the 33 patients with adequate follow-up, the outcome was favorable in 31 (93.9%).

CONCLUSION

In every febrile traveller returned from Africa, imported falciparum malaria should be an essential part of differential diagnostic considerations.

A malaria death due to an imported Plasmodium falciparum infection in Sri Lanka during the prevention of re-establishment phase of malaria

BACKGROUND

Sri Lanka has maintained a rigorous programme to prevent the re-establishment of malaria ever since the disease was eliminated in October 2012. It includes efforts to sustain case surveillance to ensure early diagnosis and management of malaria. Yet, in April of 2023 the death occurred of an individual with imported malaria.

CASE PRESENTATION

The deceased was a 37-year-old Sri Lankan male who returned to Sri Lanka on the 10th of April after a business trip to several countries including Tanzania. He was febrile on arrival and consulted three Allopathic Medical Practitioners in succession in his home town in the Western Province of Sri Lanka, over a period of 5 days starting from the very day that he arrived in the country. Malaria was not tested for at any of these consultations and his clinical condition deteriorated. On the evening of 14th of April he was admitted to the medical intensive care unit of a major private hospital in the capital city of Colombo with multiple organ failure. There, on a request by the treating physician blood was tested for malaria and reported early the next morning as Plasmodium falciparum malaria with a high parasitaemia (> 10%). The patient died shortly after on the 15th of April before any anti-malarial medication was administered. The deceased had been a frequent business traveller to Africa, but with no past history of malaria. He had not taken chemoprophylaxis for malaria on this or previous travels to Africa.

DISCUSSION

The patient's P. falciparum infection progressed rapidly over 5 days of arriving in Sri Lanka leading to severe malaria without being diagnosed, despite him seeking healthcare from three different Medical Practitioners. Finally, a diagnosis of malaria was made on admission to an intensive care unit; the patient died before anti-malarial medicines were administered.

CONCLUSIONS

This first death due to severe P. falciparum malaria reported in Sri Lanka after elimination of the disease was due to the delay in diagnosing malaria.

Prevalence, anti-malarial chemoprophylaxis and causes of deaths for severe imported malaria: A systematic review and meta-analysis

BACKGROUND

There are limited data regarding prevalence, anti-malarial chemoprophylaxis, and causes of death for severe imported malaria. Thus, we conducted a systematic review and meta-analysis to characterise these variables.

METHODS

We searched studies reporting deaths attributable to severe imported malaria. The following pooled prevalence rates were determined: 1) the pooled prevalence of severe malaria among patients with imported malaria, 2) the pooled prevalence of deaths among patients with severe imported malaria, 3) the pooled prevalence of anti-malarial chemoprophylaxis among patients with severe imported malaria, and 4) the causes of death among patients with severe imported malaria.

RESULTS

The search identified 52 studies that were mainly conducted in Europe (25, 48.1%), North America (16, 30.8%) and Asia (7, 13.5%). The pooled prevalence of severe imported malaria was 12.5% (95% confidence interval [CI] = 10.3%-14.6%, I² = 99.32%, 12393 severe cases/118325 imported cases). The pooled prevalence of deaths attributable to severe imported malaria was 5.1% (95% CI = 4.0%-6.2%, I² = 91.72%, 721 deaths/16310 severe cases). The pooled prevalence of adequate anti-malarial chemoprophylaxis among patients with severe imported malaria was 9.7% (95% CI = 6.5%-13.0%, I² = 89.9%, 203/2049 cases). The most common cause of death was multi-organ failure (12.3%).

CONCLUSION

The results highlighted the need for education and preventative measures for travellers, immigrants, or workers who plan to visit malaria-endemic areas to minimize the risk of severe disease or death.

Assessment of electronic surveillance and knowledge, attitudes, and practice (KAP) survey toward imported malaria surveillance system acceptance in France

Objective

An electronic surveillance system was released to monitor morbidity and mortality incidence of imported malaria cases, investigate autochthonous cases, and assess chemosensitivity of Plasmodium isolates among travelers to and from endemic areas. The aim of this study is to evaluate the use of an electronic surveillance system for imported malaria in France.

Materials and Methods

Three main indicators were used to assess the online malaria web-based surveillance system: (1) the quality of the surveillance system; (2) the capacity of the online system to early warning in case of particular events of public health; (3) the knowledge, attitude, and practice of online electronic system by practitioners of malaria network in France.

Results

Overall, the median time onset a case is reported to the system decrease by 99%, ranging from 227 days (144–309) to 2 days (1–6) in 2006 and 2020, respectively.

Conclusion

The online malaria surveillance system in France has demonstrated its effectiveness and can therefore be extended to carry out numerous investigations linked to research on malaria.

We describe the surveillance activities of the imported malaria surveillance in travelers from and to endemic areas in France caused by the bite of infected mosquitoes. Furthermore, we evaluate how the participants to the network navigate, appreciate, and report their diagnosed cases to the French National Reference Center for malaria. The main findings are the stability of the network from 1996 through 2020; the reduction of the time between the diagnosis and the declaration of the case in the database. This study provides the effectiveness and ability of this surveillance system to carry out numerous investigations linked to research on malaria and the willingness of their members to participate in the surveillance of imported malaria.

High prevalence of malaria in a non-endemic setting among febrile episodes in travellers and migrants coming from endemic areas: a retrospective analysis of a 2013-2018 cohort

Background

The study aimed to analyse the likelihood of imported malaria in people with a suggestive clinical picture and its distinctive characteristics in a hospital in the south of Madrid, Spain.

Methods

Observational retrospective study that consisted of a review of all medical files of patients with any malaria test registered at Móstoles University Hospital between April 2013 and April 2018. All suspected malaria cases were confirmed by Plasmodium spp. polymerase chain reaction (PCR).

Results

Of the 328 patients with suspected malaria (53.7% migrant-travellers; 38.7% visitors; 7.6% travellers), 108 cases were confirmed (101 by Plasmodium falciparum), accounting for a 33% positive sample rate. Sixteen cases were diagnosed only by PCR. Patients with malaria, compared to those without, presented predominantly with fever (84% vs. 65%), were older (34 vs. 24 years), sought medical attention earlier (17d vs. 32d), had a greater number of previous malaria episodes (74% vs. 60%), lower levels of platelets (110,500µL vs. 250,000µL), and higher of bilirubin (0.6 mg/dL vs. 0.5 mg/dL). Severe malaria was present in 13 cases; no deaths were recorded. Malaria diagnosis showed a bimodal distribution with two peaks: June to September and November to January.

Conclusions

Malaria is still a common diagnosis among febrile patients coming from the tropics specially among migrant travellers. Fever, thrombocytopenia, and/or high bilirubin levels should raise suspicion for this parasitic infection. Prompt diagnosis is crucial to avoid severe cases and deaths.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03984-9.

Propensity Score Analysis of Artesunate Versus Quinine for Severe Imported Plasmodium falciparum Malaria in France

BACKGROUND

Little is known on the use of artesunate compared with quinine for the treatment of imported malaria cases in nonendemic countries with a high level of care. Therefore, we compared the 2 treatments in terms of mortality and hospital and intensive care unit (ICU) discharge rates.

METHODS

We analyzed the cohort of all severe imported malaria patients reported to the French National Reference Center from 2011 to 2017. After controlling for differences between quinine- and artesunate-treated individuals using the inverse probability of treatment weighting method, 28-day mortality rate was compared between the groups as well as hospital and ICU discharge rates using Kaplan-Meier estimation and weighted Cox proportional hazard models.

RESULTS

Overall, 1544 patients were enrolled. Fifty patients died, 18 in the quinine group (n = 460) and 32 in the artesunate group (n = 1084), corresponding to death rates of 3.9% and 2.9%, respectively. No difference was evident between quinine and artesunate either in mortality or in hospital discharge rate, with hazard ratios (HRs) of 1.03 (95% confidence interval [CI], 0.47-2.25) and 1.12 (95% CI, 0.94-1.34), respectively. Artesunate was associated with a faster ICU discharge rate (HR, 1.18. 95% CI, 1.02-1.36).

CONCLUSIONS

In a country with a high level of care, artesunate was associated with a shorter length of stay in the ICU, which supports the actual therapeutic transition; however, no difference was found in terms of mortality or in hospital discharge rates between artesunate- and quinine-treated patients.

Mortality from malaria in France, 2005 to 2014

Introduction

Malaria is a notifiable disease in all European Union and European Economic Area countries except Belgium and France, where only autochthonous malaria is notifiable. Although morbidity caused by malaria has been assessed, little is known about mortality incidence.

Objective

Our aim was to estimate the number of imported malaria-related deaths in hospital in metropolitan France.

Methods

We matched individual deaths reported between 1 January 2005 and 31 December 2014 to the French National Reference Centre for malaria (FNRCm) with malaria-related deaths from two other sources: the French National Registry on medical causes of death and the French national hospital discharge database. A capture–recapture method with log-linear modelling was used. Age, sex and place of death stratification were applied to remove heterogeneity.

Results

The estimated malaria-related deaths in metropolitan France during the study period were 205 (95% confidence interval (CI): 191–219). The annual mean number of malaria-related deaths was estimated at 21 (95% CI: 19–22). The FNRCm malaria-related deaths surveillance had a 38% sensitivity (95% CI: 32–44). Among 161 in-hospital individual malaria-related deaths reported from three data sources, the sex ratio (male to female) was 2.6. Median age of the patients was 57 years, ranging from 1 to 89 years.

Conclusion

The pertinent finding of this report is that malaria-related death records were significantly more complete than case records. Therefore, data comparison of imported malaria morbidity and mortality between countries should imperatively be assessed using standard indicators weighted according to the completeness of health surveillance systems.

Epidemiology of Plasmodium falciparum Malaria and Risk Factors for Severe Disease in Hubei Province, China

This study aimed to describe the epidemiology of Plasmodium falciparum malaria and identify risk factors for severe disease in Hubei Province, China, using a case-based survey of retrospective data from 2013 to 2018. From 2013 to 2018, a total of 763 imported malaria cases were reported in Hubei Province; 69.2% (528/763) cases were caused by P. falciparum species. The proportion of malaria caused by P. falciparum increased from 66.7% in 2013 to 74.0% in 2018 (χ² = 21.378, P < 0.05). Plasmodium falciparum malaria was reported in 77 counties of Hubei Province. The majority of imported P. falciparum cases originated from Africa (98.9%, 522/528); 9.7% (51/528) of patients infected with P. falciparum developed severe malaria. Three deaths (case fatality rate: 0.6%) were related to imported P. falciparum malaria. Risk factors for severe malaria were being female (odds ratio [OR] = 3.593, 95% CI: 1.003-12.874), age ≥ 50 years (OR = 2.674, 95% CI: 1.269-5.634), > 3 days between symptom onset and diagnosis (OR = 2.383, 95% CI: 1.210-4.693), and the first-visit medical institution at the township level or lower (OR = 2.568, 95% CI: 1.344-4.908). Malaria prevention should be undertaken among high-risk groups, infection with P. falciparum should be detected early to prevent severe disease and death, and healthcare providers in health facilities at the township level should be trained on early recognition of malaria.

Risk of malaria associated with travel to malaria-endemic areas to visit friends and relatives: a population-based case-control study

BACKGROUND

Reports relying on population-based data and using epidemiologic methodologies such as case-control study designs for malaria in travellers and multivariable regression analysis of risk factors are rare. The aim of this study was to investigate the epidemiologic characteristics of travellers who tested positive for malaria after visiting friends and relatives in malaria-endemic areas to determine the risk of malaria associated with such travel.

METHODS

Using routinely collected data from a population-based laboratory database, we conducted a case-control study of symptomatic people returning from travel to malaria-endemic areas who presented for malaria testing in Calgary from 2013 to 2017. We used a multivariable logistic regression to analyze the association between the presence of malaria and other risk factors.

RESULTS

There were 251 confirmed malaria cases during the study period, of which 219 were matched to 1129 returning travellers without malaria. Based on the multivariable regression, the odds of a traveller who visited friends and relatives in malariaendemic areas being diagnosed with malaria was 2.82 (95% confidence interval [CI] 1.42-5.92) times greater than that of other travellers to these regions. Adults (odds ratio [OR] 3.62, 95% CI 1.66-8.84), males (OR 2.70, 95% CI 1.56-4.80), travellers to Africa (OR 11.52, 95% CI 6.33-22.05) and those who did not seek pretravel advice (OR 0.38, 95% CI 0.20-0.70) were more likely to be diagnosed with malaria. Although those travelling to visit friends and relatives tended to stay longer in endemic areas than other travellers, visit duration was not associated with an increased likelihood of malaria in the model. The annual incidence of malaria was highest (13.34 per 100 000) in metropolitan wards associated with lower socioeconomic status and immigrant communities.

INTERPRETATION

Travellers who visited friends and relatives in malaria-endemic areas were less likely than other travellers to these regions to seek pretravel advice, take prophylaxis and have a visit duration less than 2 weeks; travelling to Africa and being male increased the odds of being diagnosed with malaria, independent of other factors. These data suggest that targeted strategies to provide pretravel care to travellers who visit friends and relatives in malaria-endemic areas may aid in reducing the burden of malaria in this population.

Plasmodium vivax severe imported malaria in two migrants in France

BACKGROUND

With less than one severe case per year in average, Plasmodium vivax is very rarely associated with severe imported malaria in France. Two cases of P. vivax severe malaria occurred in patients with no evident co-morbidity. Interestingly, both cases did not occur at the primary infection but during relapses.

CASE PRESENTATIONS

Patient 1: A 27-year old male, born in Afghanistan and living in France since 2012, was admitted on August 2015 to the Avicenne hospital because of abdominal pain, intense headache, fever and hypotension. The patient was haemodynamically unstable despite 5 L of filling solution. A thin blood film showed P. vivax trophozoites within the red blood cells. To take care of the septic shock, the patient was given rapid fluid resuscitation, norepinephrine (0.5 mg/h), and intravenous artesunate. Nested polymerase chain reactions of the SSUrRNA gene were negative for Plasmodium falciparum but positive for P. vivax. The patient became apyretic in less than 24H and the parasitaemia was negative at the same time. Patient 2: A 24-year old male, born in Pakistan and living in France, was admitted on August 2016 because of fever, abdominal pain, headache, myalgia, and nausea. The last travel of the patient in a malaria endemic area occurred in 2013. A thin blood film showed P. vivax trophozoites within the red blood cells. The patient was treated orally by dihydroartemisinin-piperaquine and recovered rapidly. Nine months later, the patient returned to the hospital with a relapse of P. vivax malaria. The malaria episode was uncomplicated and the patient recovered rapidly. Three months later, the patient came back again with a third episode of P. vivax malaria. Following a rapid haemodynamic deterioration, the patient was transferred to the intensive care unit of the hospital. In all the patient received 10 L of filling solution to manage the septic shock. After 5 days of hospitalization and a specific treatment, the patient was discharged in good clinical conditions.

CONCLUSION

Clinicians should be aware of the potential severe complications associated with P. vivax in imported malaria, even though the primary infection is uncomplicated.

Hypertension is associated with an increased risk for severe imported falciparum malaria: a tertiary care hospital based observational study from Berlin, Germany

Background

Increasing numbers of aging individuals with chronic co-morbidities travel to regions where falciparum malaria is endemic. Non-communicable diseases are now leading risk factors for death in such countries. Thus, the influence of chronic diseases on the outcome of falciparum malaria is an issue of major importance. Aim of the present study was to assess whether non-communicable diseases increase the risk for severe imported falciparum malaria.

Methods

A retrospective observational study of all adult cases with imported falciparum malaria hospitalized between 2001 and 2015 in the tertiary care Charité University Hospital, Berlin, was performed.

Results

A total of 536 adult patients (median age 37 years; 31.3% female) were enrolled. Of these, 329 (61.4%) originated from endemic countries, 207 patients (38.6%) from non-endemic regions. Criteria for severe malaria were fulfilled in 68 (12.7%) cases. With older age, lack of previous malaria episodes, being a tourist, and delayed presentation, well-characterized risk factors were associated with severe malaria in univariate analysis. After adjustment for these potential confounders hypertension (adjusted odds ratio aOR, 3.06 95% confidence interval, CI 1.34–7.02), cardiovascular diseases (aOR, 8.20 95% CI 2.30–29.22), and dyslipidaemia (aOR, 6.08 95% CI 1.13–32.88) were individual diseases associated with severe disease in multivariable logistic regression. Hypertension proved an independent risk factor among individuals of endemic (aOR, 4.83, 95% CI 1.44–16.22) as well as of non-endemic origin (aOR, 3.60 95% CI 1.05–12.35).

Conclusions

In imported falciparum malaria hypertension and its related diseases are risk factors for severe disease.

Epidemiologic Trends in Malaria Incidence Among Travelers Returning to Metropolitan France, 1996-2016

IMPORTANCE

Despite annually adapted recommendations to prevent malaria in travelers to endemic areas, France is still the industrialized country reporting the highest number of imported cases of malaria. Better understanding of the epidemiologic context and evolution during the past 2 decades may help to define a better preventive strategy.

OBJECTIVE

To study epidemiologic trends of imported cases of malaria in travelers in geographic territories of France on the European continent (metropolitan France) from 1996 through 2016 to potentially explain the persistence of high imported malaria incidence despite national preventive measures.

DESIGN, SETTING, AND PARTICIPANTS

In a cross-sectional study, between January 1 and May 31, 2018, data were extracted from the French National Reference Center of Malaria Surveillance. Trends in patients with imported malaria in association with age, sex, ethnicity, purpose of travel, malaria species, severity of illness, case mortality rate, and endemic countries visited were analyzed in 43 333 malaria cases among civilian travelers living in metropolitan France.

MAIN OUTCOMES AND MEASURES

Evolution of the main epidemiologic characteristics of patients with imported malaria.

RESULTS

Among the 43 333 patients with imported malaria in civilian travelers included in the study, 24 949 were male (62.4%), and 8549 were younger than 18 years (19.9%). A total of 28 658 malaria cases (71.5%) were among African individuals, and 10 618 cases (26.5%) among European individuals. From 1996 through 2016, the number of confirmed malaria cases peaked at 3400 cases in 2000, then declined to 1824 cases in 2005 and stabilized thereafter to approximately 1720 malaria cases per year. A total of 37 065 cases (85.5%) were due to Plasmodium falciparum. The proportion of malaria cases among African individuals rose from 53.5% in 1996 to 83.4% in 2016, and the most frequent motivation for traveling was visiting friends and relatives (25 329 [77.1%]; P < .001). Despite an increase in the proportion of severe cases, which rose from 131 cases (8.9%) in 1996 to 279 cases (16.7%) in 2016 (P < .001), mortality remained stable, being approximately 0.4% during the study period.

CONCLUSIONS AND RELEVANCE

Beyond the apparent stability of the number of imported malaria cases in France, significant changes appear to have occurred among the population who developed malaria infection following travel in endemic areas. These changes may imply that adaptation of the preventive strategy is needed to reduce the burden of the disease among travelers.

Management of severe imported malaria in adults

Severe malaria accounts for approximately 10% of all cases of imported malaria in France; cases are mainly due to Plasmodium falciparum, while other Plasmodium species are possible but uncommon (P. vivax, P. knowlesi, P. malariae, and P. ovale). On the basis of WHO criteria for endemic areas, the French criteria defining severe imported malaria in adults have been progressively adapted to the European healthcare level. Management of severe imported malaria is a diagnostic and treatment emergency and must be initially conducted in the intensive care unit. Anti-infective treatment is now based on intravenous artesunate, which must be available in every hospital of the country likely to receive severe imported malaria patients. Intravenous quinine is thus used as a second-line treatment and is restricted to limited indications. Critical care management of organ failure is essential, particularly in patients presenting with very severe malaria. To date, no adjunctive therapy (including exchange transfusion) has demonstrated clear beneficial effects.

Prise en charge du paludisme grave d’importation de l’adulte

En France, le paludisme grave d’importation concerne environ 12 à 14 % des accès palustres et implique très majoritairement Plasmodium falciparum. À partir de la définition du paludisme grave de l’Organisation mondiale de la santé utilisée en zone d’endémie palustre, la définition française du paludisme grave d’importation de l’adulte a été adaptée aux données et au contexte européens. La prise en charge du paludisme grave est une urgence diagnostique et thérapeutique qui doit être réalisée initialement en réanimation. Le traitement curatif du paludisme grave d’importation repose maintenant sur l’artésunate intraveineux (IV) qui doit être disponible dans chaque hôpital susceptible de recevoir ces patients. Dès lors, la quinine IV devient un traitement de seconde ligne réservé à quelques circonstances. La prise en charge symptomatique des défaillances d’organes est primordiale, notamment au cours des formes les plus sévères. Enfin, aucun traitement adjuvant n’a prouvé, à ce jour, son efficacité en pratique clinique.

Severe imported malaria in children in France. A national retrospective study from 1996 to 2005

BACKGROUNDS

Malaria is a leading cause of imported febrile illnesses in pediatric travelers, but few studies have addressed severe imported pediatric malaria. We aimed to determine the risk factors and the features of imported pediatric severe malaria.

METHODS

We conducted a retrospective, descriptive study using the French National Reference Center for Imported Malaria database, in children aged 0-15 years who were hospitalized with a falciparum malaria from January 1st 1996 to December 31th 2005. Uncomplicated and severe cases of falciparum malaria were compared to identify risk factors for severe cases. In the hospitals that reported more than five severe cases during the study period, we evaluated severe cases for prognostic factors and assessed the accuracy WHO criteria for predicting severity. Given the rarity of deaths, adverse outcomes were defined as requiring major therapeutic procedures (MTPs)-e.g., sedation, mechanical ventilation, nasal oxygen therapy, blood transfusions, hemodialysis, fluid resuscitation-or pediatric intensive care unit (PICU) admission.

RESULTS

Of 4150 pediatric malaria cases included in the study, 3299 were uncomplicated and 851 (20.5%) were severe. Only one death was recorded during this period. Predictors for severe falciparum malaria were: age <2 years (OR = 3.2, 95% CI = 2.5-4.0, p <0.0001) and a travel in the Sahelian region (OR = 1.7, 95% CI = 1.3-2.0, p = 0.0001). Of 422 severe malaria cases, a stay in a Sahelian region, lack of chemoprophylaxis, age <2 years or thrombocytopenia <100 x 10^3/mm^3 predicted adverse outcomes. Except for the hyperparasitemia threshold of 4%, the main WHO 2000 criteria for severe malaria reliably predicted adverse outcomes. In our study, the threshold of parasitemia most predictive of a poor outcome was 8%.

CONCLUSION

In imported pediatric malaria, children younger than 2 years deserve particular attention. The main WHO 2000 criteria for severity are accurate, except for the threshold of hyperparasitemia, which should be revised.

Severe malaria in Europe: an 8-year multi-centre observational study

Background

Malaria remains one of the most serious infections for travellers to tropical countries. Due to the lack of harmonized guidelines a large variety of treatment regimens is used in Europe to treat severe malaria.

Methods

The European Network for Tropical Medicine and Travel Health (TropNet) conducted an 8-year, multicentre, observational study to analyse epidemiology, treatment practices and outcomes of severe malaria in its member sites across Europe. Physicians at participating TropNet centres were asked to report pseudonymized retrospective data from all patients treated at their centre for microscopically confirmed severe Plasmodium falciparum malaria according to the 2006 WHO criteria.

Results

From 2006 to 2014 a total of 185 patients with severe malaria treated in 12 European countries were included. Three patients died, resulting in a 28-day survival rate of 98.4%. The majority of infections were acquired in West Africa (109/185, 59%). The proportion of patients treated with intravenous artesunate increased from 27% in 2006 to 60% in 2013. Altogether, 56 different combinations of intravenous and oral drugs were used across 28 study centres. The risk of acute renal failure (36 vs 17% p = 0.04) or cerebral malaria (54 vs 20%, p = 0.001) was significantly higher in patients ≥60 years than in younger patients. Respiratory distress with the need for mechanical ventilation was significantly associated with the risk of death in the study population (13 vs 0%, p = 0.001). Post-artemisinin delayed haemolysis was reported in 19/70 (27%) patients treated with intravenous artesunate.

Conclusion

The majority of patients with severe malaria in this study were tourists or migrants acquiring the infection in West Africa. Intravenous artesunate is increasingly used for treatment of severe malaria in many European treatment centres and can be given safely to European patients with severe malaria. Patients treated with intravenous artesunate should be followed up to detect and manage late haemolytic events.

Plasmodium falciparum malaria importation from Africa to China and its mortality: an analysis of driving factors

Plasmodium falciparum malaria importation from Africa to China is rising with increasing Chinese overseas investment and international travel. Identifying networks and drivers of this phenomenon as well as the contributors to high case-fatality rate is a growing public health concern to enable efficient response. From 2011-2015, 8653 P. falciparum cases leading to 98 deaths (11.3 per 1000 cases) were imported from 41 sub-Saharan countries into China, with most cases (91.3%) occurring in labour-related Chinese travellers. Four strongly connected groupings of origin African countries with destination Chinese provinces were identified, and the number of imported cases was significantly associated with the volume of air passengers to China (P = 0.006), parasite prevalence in Africa (P < 0.001), and the amount of official development assistance from China (P < 0.001) with investment in resource extraction having the strongest relationship with parasite importation. Risk factors for deaths from imported cases were related to the capacity of malaria diagnosis and diverse socioeconomic factors. The spatial heterogeneity uncovered, principal drivers explored, and risk factors for mortality found in the rising rates of P. falciparum malaria importation to China can serve to refine malaria elimination strategies and the management of cases, and high risk groups and regions should be targeted.

Malaria in travellers returning or migrating to Canada: surveillance report from CanTravNet surveillance data, 2004-2014

BACKGROUND

Malaria remains the most common specific cause of fever in returned travellers and can be life-threatening. We examined demographic and travel correlates of malaria among Canadian travellers and immigrants to identify groups for targeted pretravel intervention.

METHODS

Descriptive data on ill returned Canadian travellers and immigrants presenting to a CanTravNet site between 2004 and 2014 with a diagnosis of malaria were analyzed. Data were collected using the GeoSentinel data platform. This network comprises 63 specialized travel and tropical medicine clinics, including 7 Canadian sites (Vancouver, Calgary, Toronto, Ottawa, Winnipeg and Montréal), that contribute anonymous, delinked, clinician- and questionnaire-based travel surveillance data on all ill travellers examined to a centralized Structure Query Language database.

RESULTS

During the study period, 20 345 travellers and immigrants were evaluated, and 93% had a travel-related diagnosis. Of these, 437 (2.1%) patients received 456 malaria diagnoses, the most common species being Plasmodium falciparum (n = 282, 61.8%). People travelling to visit friends and relatives were most well-represented (n = 169, 38.7%), followed by business travellers (n = 71, 16.2%). Sub-Saharan Africa was the most common source region, accounting for 341 (74.8%) malaria diagnoses, followed by South Central Asia (n = 55, 12%). Nigeria was the most well-represented source country, accounting for 41 cases (9.0%). India, a high-volume destination for Canadians, accounted for 40 cases (8.8%), 36 of which were caused by Plasmodium vivax. Of 456 malaria diagnoses, 26 (5.7%) were severe. Of 377 nonimmigrant travellers with malaria, 19.9% (n = 75) travelled for less than 2 weeks, and 7.2% (n = 27) travelled for less than 1 week.

INTERPRETATION

This analysis provides an epidemiologic framework for Canadian practitioners encountering prospective and returned travellers. It confirms the importance of preventive measures and surveillance associated with travel to sub-Saharan Africa and India, particularly by travellers visiting friends or relatives. Short-duration travel confers important malaria risk.

Hospitalization and ambulatory care in imported-malaria: evaluation of trends and impact on mortality. A prospective multicentric 14-year observational study

BACKGROUND

Hospitalization is usually recommended for imported malaria. The goal of the present study is to evaluate the evolution in clinical pathways while measuring their impact on mortality.

METHODS

This is a 14-year prospective observational study divided into three periods. We evaluated for adult (≥15 years) and paediatric (<15 years) case trends in severity, clinical pathways (hospitalization in medical ward (MW) or intensive care unit (ICU), ambulatory care) and mortality.

RESULTS

In total, 21,386 imported malaria cases were included, 4269 of them were paediatrics (20 %). Rises in severe forms for adults [from 8 % in period 1-14 % in period 3 (p = 0.0001)] and paediatrics [from 12 to 18 % (p < 0.0001)] were found. For adults, MW admission rates decreased [-15 % (CI 95 % -17; -13)] while ambulatory care [+7 % (CI 95 % 5-9)] and ICU admission rates [+4 % (CI 95 % 3-5)] increased. For paediatrics, increase in ICU admissions (+3 %) was shown. We did not observe any change in overall mortality during the study periods, whether among adults or children, regardless of care pathway.

CONCLUSIONS

The present study indicates a changing management of imported malaria in adults, with an increasing trend for ambulatory care. The absence of change in mortality for adults indicates that ambulatory care can be proposed for adults presenting non-severe imported malaria.

Malaria in the returning older traveler

BACKGROUND

Increased co-morbidities and physiological changes mean older patients may be at higher risk of adverse outcomes from certain imported illnesses. One of the most commonly diagnosed imported infections in returning travelers is malaria. Increasing age is strongly and independently associated with increasing morbidity and mortality from malaria. Delayed diagnosis leads to higher risks of poor clinical outcomes in older patients presenting with malaria. The objective of this study was to quantify malaria presentations in older patients as a percentage of total malaria presentations, compare length of hospital stay (LOS) between the older and younger cohort, and to describe medical co-morbidities, length of time to diagnosis and factors contributing to delayed diagnosis and increased LOS in the older cohort.

METHODS

A retrospective cohort study was undertaken in two university hospitals of all patients aged 65 years or older presenting with malaria from 2002-2012. A national hospital inpatient database was used to identify patients of all ages with a discharge diagnosis of malaria over this ten year period, and quantify LOS in those aged <65 and those aged 65 years or older. The case-notes for all of the older cohort were reviewed.

RESULTS

There were a total of 203 cases, 12 of whom were aged ≥65 years (5.9 %- total). Median time to diagnosis in this older group was two days (range 0-35), median LOS was eight days (range 1-77), compared to a median LOS of three days in those aged <65 years. All patients aged ≥65 years presented with fever. Travel history was documented in only 6/12 charts, and 11/12 had two or more co-morbid illnesses. Six of the 12 patients were not diagnosed or treated within 48 h of presentation.

CONCLUSIONS

This case series highlights the need for appropriate history-taking and timely diagnosis of the older traveler returning with fever, as delayed diagnosis and treatment can contribute to prolonged hospital stay and increased morbidity. With increasing numbers of older travelers, physicians must remain vigilant to the presence of imported illnesses, particularly malaria, in older patients with unexplained fever.

Delayed-onset hemolytic anemia in patients with travel-associated severe malaria treated with artesunate, France, 2011-2013

Artesunate is the most effective treatment for severe malaria. However, delayed-onset hemolytic anemia has been observed in ≈20% of travelers who receive artesunate, ≈60% of whom require transfusion. This finding could discourage physicians from using artesunate. We prospectively evaluated a cohort of 123 patients in France who had severe imported malaria that was treated with artesunate; our evaluation focused on outcome, adverse events, and postartesunate delayed-onset hemolysis (PADH). Of the 123 patients, 6 (5%) died. Overall, 97 adverse events occurred. Among the 78 patients who received follow-up for >8 days after treatment initiation, 76 (97%) had anemia, and 21 (27%) of the 78 cases were recorded as PADH. The median drop in hemoglobin levels was 1.3 g/dL; 15% of patients with PADH had hemoglobin levels of <7 g/dL, and 1 required transfusion. Despite the high incidence of PADH, the resulting anemia remained mild in 85% of cases. This reassuring result confirms the safety and therapeutic benefit of artesunate.

Imported malaria in portugal 2000-2009: a role for hospital statistics for better estimates and surveillance

Background. Although eradicated in Portugal, malaria keeps taking its toll on travelers and migrants from endemic countries. Disease notification is mandatory but is compromised by underreporting. Methods. A retrospective study on malaria hospitalizations for 10 consecutive years (2000–2009) was conducted. Data on hospitalizations and notifications were obtained from Central Administration of Health System and Health Protection Agency, respectively. For data selection ICD-9 CM and ICD-10 were used: codes 084^*, 647.4, and B50–B54. Variables were gender, age, agent and origin of infection, length of stay (LOS), lethality, and comorbidities. Analysis included description, hypothesis testing, and regression. Results. There were 2003 malaria hospitalizations and 480 notified hospitalized cases, mainly in young male adults. P. falciparum was the main agent of infection acquired mainly in sub-Saharan Africa. Lethality was 1.95% and mean LOS was 8.09 days. Older age entailed longer LOS and increased lethality. Discussion. From 2000 to 2009, there were 2003 malaria hospitalizations with decreasing annual incidence, these numbers being remarkably higher than those notified. The national database of diagnosis related groups, reflecting hospitalizations on NHS hospitals, may be an unexplored complementary source for better estimates on imported malaria.

Duration of residency in a non-endemic area and risk of severe malaria in African immigrants

In malaria-endemic areas, adults very rarely succumb to severe malaria, suggesting that immunity to severe disease is life-long under conditions of repeated exposure. To what extent this protection persists in the absence of exposure remains to be established. The aim of this study was to assess whether duration of residency in a malaria-free country affects the risk for severe malaria in immigrants originating from sub-Saharan Africa. We conducted a retrospective chart review of 948 cases of malaria diagnosed in Stockholm, Sweden in 1995-2013. Among 501 adult patients with Plasmodium falciparum (315 of endemic origin and 186 of non-endemic origin, mainly Sweden), 41 (8.2%) had severe malaria according to WHO criteria (including 5% with parasitaemia), 22 (4.4%) had factors prognostic of poor outcome, and 35 (7.0%) were admitted to intensive care. Overall, patient origin did not affect the odds of severe malaria, according to any of these definitions. However, when the immigrants were stratified with regard to their duration of residency in Sweden, the risk of factors prognostic for poor outcome was associated with duration of prior residency in a malaria-free country among patients of endemic origin (p 0.02), and immigrants who had lived for ≥ 15 years in Sweden had a similar risk as non-immune travellers. The results of this explorative study suggest that, although immunity to severe malaria is maintained for several years in African adults, this protection might be lost with time without repeated re-exposure. A larger study, preferably including multiple centres, will be needed to confirm our findings.

The burden of imported malaria in Portugal 2003 to 2012

Increasing international travel and expatriation to sub-Saharan countries where malaria is endemic has raised public health concerns about the burden of imported malaria cases in Portugal. From 2009 to 2012, there was a 60% increase in malaria hospitalizations, contradicting the declining trend observed since 2003. Older age was associated with longer length of stay in hospital and higher lethality.

Imported malaria in Poland 2003 to 2011: implications of different travel patterns

BACKGROUND

The number of imported malaria cases in Poland compared with other European countries remains low. However, in view of the high mortality and the large proportion of severe clinical forms, a better understanding of the problem is required.

METHODS

Data reported to the surveillance system in Poland between 2003 and 2011 were reviewed retrospectively. All cases were laboratory confirmed as outlined by the EU case definition. Statistical analysis was performed using Epi Info 3.5.3 and STATA 10.

RESULTS

A total of 189 confirmed malaria cases, including 5 that were fatal, were reported in Poland during the study period. All cases were imported: 72% came from Africa. Among cases with a species-specific diagnosis, 118 (73%) were caused by Plasmodium falciparum. The median age of individuals afflicted was 36 years and 74% were males. Most cases occurred among work-related travelers (40%) or tourists (38%). Individuals born in malaria-endemic countries constituted 12% of all cases. The severe malaria form was identified in 23% of all cases and was more frequent among cases caused by P. falciparum (32%), in people older than 50 years (39%), and in cases when diagnosis was delayed (36%). The severe form occurred only in 9% of cases originating from malaria-endemic countries and there were no fatalities in this group. Fatal outcomes were associated with a delay in diagnosis (fatality = 10.5%) and falciparum malaria (fatality = 4%). Most of the delays resulted from a delay in seeking medical care, and less frequently due to misdiagnosis.

CONCLUSIONS

Tourists and work-related travelers make up most of the malaria patients in Poland and they are at a greater risk of the severe form of malaria and consequently death, possibly due to the lack of immunity. Delayed diagnosis is associated with mortality, implying low awareness of the threat that malaria poses, both among patients and doctors.

Spatiotemporal dynamics and demographic profiles of imported Plasmodium falciparum and Plasmodium vivax infections in Ontario, Canada (1990-2009)

We examined malaria cases reported to Ontario's public health surveillance systems from 1990 through 2009 to determine how temporal scale (longitudinal, seasonal), spatial scale (provincial, health unit), and demography (gender, age) contribute to Plasmodium infection in Ontario travellers. Our retrospective study included 4,551 confirmed cases of imported malaria reported throughout Ontario, with additional analysis at the local health unit level (i.e., Ottawa, Peel, and Toronto). During the 20-year period, Plasmodium vivax accounted for 50.6% of all cases, P. falciparum (38.6%), Plasmodium sp. (6.0%), P. ovale (3.1%), and P. malariae (1.8%). During the first ten years of the study (1990-1999), P. vivax (64% of all cases) was the dominant agent, followed by P. falciparum (28%); however, during the second ten years (2000-2009) the situation reversed and P. falciparum (55%) dominated, followed by P. vivax (30%). The prevalence of P. falciparum and P. vivax cases varied spatially (e.g., P. falciparum more prevalent in Toronto, P. vivax more prevalent in Peel), temporally (e.g. P. falciparum incidence increased during the 20-year study), and demographically (e.g. preponderance of male cases). Infection rates per 100,000 international travellers were estimated: rates of infection were 2× higher in males compared to females; rates associated with travel to Africa were 37× higher compared to travel to Asia and 126× higher compared to travel to the Americas; rates of infection were 2.3-3.5× higher in June and July compared to October through March; and rates of infection were highest in those 65-69 years old. Where exposure country was reported, 71% of P. falciparum cases reported exposure in Ghana or Nigeria and 63% of P. vivax cases reported exposure in India. Our study provides insights toward improving pre-travel programs for Ontarians visiting malaria-endemic regions and underscores the changing epidemiology of imported malaria in the province.

Epidemiology of imported malaria give support to the hypothesis of 'long-term' semi-immunity to malaria in sub-Saharan African migrants living in France

BACKGROUND

Short-term semi-immunity to malaria in sub-Saharan African migrants who have recently arrived in non-endemic countries results in less severe imported malaria. Our aim was to investigate the factors associated with imported malaria that would favour the hypothesis of a 'long-term' semi-immunity to malaria in adult travellers of sub-Saharan origin living in France and visiting family or relatives in their country of origin (VFR group).

METHOD

The epidemiological, clinical and biological characteristics of imported Plasmodium falciparum malaria in VFR were compared with those of travellers of European origin (TEO). Newly arrived African migrants and European expatriates were excluded.

RESULTS

This retrospective study included 106 adult VFR (30%) and 240 adult TEO (70%) with imported P. falciparum malaria treated at the University Hospital Center of Bordeaux between 2000 and 2007. The main regions visited were West Africa (58%) and Central Africa (34%). P. falciparum was associated with severe malaria in 8% of patients (VFR 3% vs. TEO 11%), of which two TEO died. In univariate analysis, the factors associated with P. falciparum malaria in VFR vs. TEO were: female sex, younger age, less frequent use of mosquito nets, poor compliance with chemoprophylaxis, less severe malaria without death, less severe thrombocytopenia and a tendency towards a lower level of parasitaemia and higher haemoglobinaemia. In multivariate analysis, the only factor to be independently associated with P. falciparum malaria in VFR compared to TEO was less frequent severe malaria.

CONCLUSIONS

Our results give support to the hypothesis of 'long-term' semi-immunity to malaria in VFR living in France.

Management of severe malaria in the intensive care unit

Severe malaria is a medical emergency requiring early intervention to prevent death. This article highlights key aspects of the management of severe malaria syndromes in the intensive care unit, with a focus on individual case management of imported malaria. Key differences in the presentation, management, and outcomes of severe malaria by endemicity and by age group are emphasized. In all groups with severe malaria, intravenous artesunate is the antimalarial agent of choice. This article discusses specific antimalarial therapies, optimal supportive management strategies, differences from strategies for bacterial sepsis, and trials of adjunctive therapy for severe malaria in humans.

Artemisinin based combination therapy in travel medicine

A steadily increasing number of Western travellers are exposed to malaria. Also, numbers of migrants from malarious areas are increasing. Fast and effective treatment options are needed to ensure effective malaria treatment in these groups in the future. Artemisinin combinations are well tolerated and have shown high efficacy in malaria endemic areas. Since 2001, 42 malaria endemic countries, 23 of them in Africa, have adopted artemisinin based combination therapies recommended by WHO. An additional 14 countries are in the process of changing their malaria treatment policy. Studies in non-immune travellers confirm a rapid parasite clearance time and very low rate of side effects. Outpatient clinics and hospitals in non-endemic countries should have standard operating procedures for diagnosing and managing patients with malaria. In this setting, artemisinin combinations should be available for treatment of uncomplicated malaria as they are clearly superior to any other oral antimalarial in their fast reduction of parasite biomass and in decreasing clinical symptoms. Also, they are the drugs of choice for travellers who are advised to carry stand-by emergency treatment during their journey.

Compliance with antimalarial chemoprophylaxis in German soldiers: a 6-year survey

PURPOSE

Since 1992, German soldiers have been deployed in areas where malaria is endemic. Antimalarial chemoprophylaxis (CP) is directed according to the assessed risk and is provided free of charge. Compliance is crucial if its effect is to be reliable. This study analysed compliance with directed CP in German soldiers as well as its determinants.

METHODS

Between 2003 and 2009, standardized questionnaire-based interviews were performed with 2,149 out of approximately 100,000 German soldiers who were deployed during this period in areas where malaria is endemic. The questionnaires dealt with information that the soldiers had received about malaria prior to their missions, with their adherence to mosquito-protective and antimalarial chemoprophylactic procedures, and their estimations of their individual level of exposure.

RESULTS

About 1,308 out of 2,149 interviewed soldiers had been ordered to take CP, allowing for an assessment of the outcome parameter "CP-compliance". About 76.9 % out of 1,308 soldiers to whom regular CP was directed took it regularly. The exposure variables "age", "satisfaction with malaria counselling", "perceived threat due to insects or mosquitoes" and "use of insect repellents" were positively associated with compliance with directed antimalarial CP.

CONCLUSIONS

The study confirms the findings of the French and US armies that even free-of-charge access to antimalarial medication will not lead to 100 % acceptance. The compliance problem is aggravated by the generally low age of deployed soldiers. Adequate counselling is crucial to increase adherence to antimalarial CP.

Management of imported malaria in Europe

In this position paper, the European Society for Clinical Microbiology and Infectious Diseases, Study Group on Clinical Parasitology, summarizes main issues regarding the management of imported malaria cases. Malaria is a rare diagnosis in Europe, but it is a medical emergency. A travel history is the key to suspecting malaria and is mandatory in patients with fever. There are no specific clinical signs or symptoms of malaria although fever is seen in almost all non-immune patients. Migrants from malaria endemic areas may have few symptoms.Malaria diagnostics should be performed immediately on suspicion of malaria and the gold- standard is microscopy of Giemsa-stained thick and thin blood films. A Rapid Diagnostic Test (RDT) may be used as an initial screening tool, but does not replace urgent microscopy which should be done in parallel. Delays in microscopy, however, should not lead to delayed initiation of appropriate treatment. Patients diagnosed with malaria should usually be hospitalized. If outpatient management is preferred, as is the practice in some European centres, patients must usually be followed closely (at least daily) until clinical and parasitological cure. Treatment of uncomplicated Plasmodium falciparum malaria is either with oral artemisinin combination therapy (ACT) or with the combination atovaquone/proguanil. Two forms of ACT are available in Europe: artemether/lumefantrine and dihydroartemisinin/piperaquine. ACT is also effective against Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi, but these species can be treated with chloroquine. Treatment of persistent liver forms in P. vivax and P. ovale with primaquine is indicated after excluding glucose 6 phosphate dehydrogenase deficiency. There are modified schedules and drug options for the treatment of malaria in special patient groups, such as children and pregnant women. The potential for drug interactions and the role of food in the absorption of anti-malarials are important considerations in the choice of treatment.Complicated malaria is treated with intravenous artesunate resulting in a much more rapid decrease in parasite density compared to quinine. Patients treated with intravenous artesunate should be closely monitored for haemolysis for four weeks after treatment. There is a concern in some countries about the lack of artesunate produced according to Good Manufacturing Practice (GMP).

Travel-associated illness in older adults (>60 y)

BACKGROUND

Older individuals represent a substantial proportion of international travelers. Because of physiological changes and the increased probability of underlying medical conditions, older travelers might be at higher risk for at least some travel-associated diseases.

METHODS

With the aim of describing the epidemiology of travel-associated diseases in older adults, medical data were prospectively collected on ill international travelers presenting to GeoSentinel sites from 1997 to 2009. Seven thousand thirty-four patients aged 60 years and over were identified as older travelers and were compared to 56,042 patients aged 18-45 years, who were used as the young adult reference population.

RESULTS

The proportionate morbidity of several etiological diagnoses was higher in older ill travelers compared to younger ill, including notably lower respiratory tract infections, high-altitude pulmonary edema, phlebitis and pulmonary embolism, arthropod bites, severe malaria, rickettsiosis, gastritis, peptic ulcers, esophagitis and gastroesophageal reflux disease, trauma and injuries, urinary tract infections, heart disease, and death. In contrast, acute diarrhea, upper respiratory tract infections, flu and flu-like illnesses, malaria, dengue, genital infections, sexually transmitted diseases, and schistosomiasis proportionate morbidities were lower among the older group.

CONCLUSION

Older ill travelers are more likely to suffer from certain life-threatening diseases and would benefit from reinforcement of specific preventive measures including use of anti-thrombosis compression stockings and sufficient hydration and exercises during long-distance flights, hand hygiene, use of disposable handkerchiefs, consideration of face-masks in crowded conditions, influenza and pneumococcal vaccines, progressive acclimatization to altitude, consideration of acetazolamide, and use of repellents and mosquito nets. Antibiotics for the presumptive treatment of respiratory and urinary tract infections may be considered, as well as antacid medications. At-risk patients should be referred to a specialist for medical evaluation before departing, and optimal control of co-morbidities such as cardiovascular and chronic obstructive pulmonary diseases should be achieved, particularly for high-altitude travel.

Is dengue and malaria co-infection more severe than single infections? A retrospective matched-pair study in French Guiana

Background

Dengue and malaria are two major arthropod-borne infections in tropical areas, but dual infections were only described for the first time in 2005. Reports of these concomitant infections are scarce and there is no evidence of more severe clinical and biological pictures than single infections.

Methods

To compare co-infections to dengue alone and malaria alone, a retrospective matched-pair study was conducted between 2004 and 2010 among patients admitted in the emergency department of Cayenne hospital, French Guiana.

Results

104 dengue and malaria co-infection cases were identified during the study period and 208 individuals were matched in two comparison groups: dengue alone and malaria alone. In bivariate analysis, co-infection clinical picture was more severe than separated infections, in particular using the severe malaria WHO criteria. In multivariate analysis, independent factors associated with co-infection versus dengue were: masculine gender, CRP level > 50 mg/L, thrombocytopaenia < 50 10⁹/L, and low haematocrit <36% and independent factors significantly associated with co-infections versus malaria were red cells transfusion, low haematocrit < 36%, thrombocytopaenia < 50 10⁹/L and low Plasmodium parasitic load < 0.001%.

Conclusions

In the present study, dengue and malaria co-infection clinical picture seems to be more severe than single infections in French Guiana, with a greater risk of deep thrombocytopaenia and anaemia.

Severe imported malaria in an intensive care unit: a review of 59 cases

BACKGROUND

In view of the close relationship of Portugal with African countries, particularly former Portuguese colonies, the diagnosis of malaria is not a rare thing. When a traveller returns ill from endemic areas, malaria should be the number one suspect. World Health Organization treatment guidelines recommend that adults with severe malaria should be admitted to an intensive care unit (ICU).

METHODS

Severe cases of malaria in patients admitted to an ICU were reviewed retrospectively (1990-2011) and identification of variables associated with in-ICU mortality performed. Malaria prediction score (MPS), malaria score for adults (MSA), simplified acute physiology score (SAPSII) and a score based on WHO's malaria severe criteria were applied. Statistical analysis was performed using StataV12.

RESULTS

Fifty nine patients were included in the study, all but three were adults; 47 (79,6%) were male; parasitaemia on admission, quantified in 48/59 (81.3%) patients, was equal or greater than 2% in 47 of them (97.9%); the most common complications were thrombocytopaenia in 54 (91.5%) patients, associated with disseminated intravascular coagulation (DIC) in seven (11.8%), renal failure in 31 (52.5%) patients, 18 of which (30.5%) oliguric, shock in 29 (49.1%) patients, liver dysfunction in 27 (45.7%) patients, acidaemia in 23 (38.9%) patients, cerebral dysfunction in 22 (37.2%) patients, 11 of whom with unrousable coma, pulmonary oedema/ARDS in 22 (37.2%) patients, hypoglycaemia in 18 (30.5%) patients; 29 (49.1%) patients presented five or more dysfunctions. The case fatality rate was 15.2%. Comparing the four scores, the SAPS II and the WHO score were the most sensitive to death prediction. In the univariate analysis, death was associated with the SAPS II score, cerebral malaria, acute renal and respiratory failure, DIC, spontaneous bleeding, acidosis and hypoglycaemia. Age, partial immunity to malaria, delay in malaria diagnosis and the level of parasitaemia were not associated with death in this cohort.

CONCLUSION

Severe malaria cases should be continued monitored in the ICUs. SAPS II and the WHO score are good predictors of mortality in malaria patients, but other specific scores deserve to be studied prospectively.

Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: an observational study

OBJECTIVES

To determine which travellers with malaria are at greatest risk of dying, highlighting factors which can be used to target health messages to travellers.

DESIGN

Observational study based on 20 years of UK national data.

SETTING

National register of malaria cases.

PARTICIPANTS

25,054 patients notified with Plasmodium falciparum malaria, of whom 184 died, between 1987 and 2006.

MAIN OUTCOME MEASURES

Comparison between those with falciparum malaria who died and non-fatal cases, including age, reason for travel, country of birth, time of year diagnosed, malaria prophylaxis used.

RESULTS

Mortality increased steadily with age, with a case fatality of 25/548 (4.6%) in people aged >65 years, adjusted odds ratio 10.68 (95% confidence interval 6.4 to 17.8), P<0.001 compared with 18-35 year olds. There were no deaths in the ≤ 5 year age group. Case fatality was 3.0% (81/2740 cases) in tourists compared with 0.32% (26/8077) in travellers visiting friends and relatives (adjusted odds ratio 8.2 (5.1 to 13.3), P<0.001). Those born in African countries with endemic malaria had a case fatality of 0.4% (36/8937) compared with 2.4% (142/5849) in others (adjusted odds ratio 4.6 (3.1 to 9.9), P<0.001). Case fatality was particularly high from the Gambia. There was an inverse correlation in mortality between region of presentation and number of cases seen in the region (R(2) = 0.72, P<0.001). Most delay in fatal cases was in seeking care.

CONCLUSIONS

Most travellers acquiring malaria are of African heritage visiting friends and relatives. In contrast the risks of dying from malaria once acquired are highest in the elderly, tourists, and those presenting in areas in which malaria is seldom seen. Doctors often do not think of these as high risk groups for malaria; for this reason they are important groups to target in pre-travel advice.

Clinical development of new prophylactic antimalarial drugs after the 5th Amendment to the Declaration of Helsinki

Malaria is of continuing concern in nonimmune traveling populations. Traditionally, antimalarial drugs have been developed as agents for dual indications (treatment and prophylaxis). However, since 2000, when the 5th Amendment to the Declaration of Helsinki (DH2000) was adopted, development of new malaria prophylaxis drugs in this manner has ceased. As a consequence, there may not be any new drugs licensed for this indication in the foreseeable future. Major pharmaceutical companies have interpreted DH2000 to mean that the traditional development paradigm may be considered unethical because of doubt over the likelihood of benefit to endemic populations participating in clinical studies, the use of placebo, and the sustainability of post-trial access to study medications. In this article, we explore the basis of these concerns and suggest that the traditional development paradigm remains ethical under certain circumstances. We also consider alternative approaches that may be more attractive to sponsors as they either do not use placebo, or utilize populations in endemic countries who may unambiguously benefit. These approaches represent the way forward in the future, but are at present unproven in clinical practice, and face numerous regulatory, logistical and technical challenges. Consequently, in the short term, we argue that the traditional clinical development paradigm remains the most feasible approach and is ethical and consistent with the spirit of DH2000 under the appropriate circumstances.

Molecular diagnosis and species identification of imported malaria in returning travellers in Italy

A new seminested polymerase chain reaction (sn-PCR)-based protocol was developed and used to detect and identify Plasmodium species in 1226 whole-blood samples from patients (872 Italians and 354 foreigners) with at least 1 symptom compatible with clinical malaria. The results were compared with those obtained by microscopy: 187 samples were positive by microscopy for malaria parasites and 196 were positive by sn-PCR. When compared to microscopy, the sn-PCR detected different malaria parasite species in 11 cases. In 4 of 11 cases, the sn-PCR identified 1 additional malaria parasite species not observed microscopically, suggesting increased sensitivity. In 4 samples with levels of parasitemia too low for accurate identification of species by microscopy, the sn-PCR detected 2 P. falciparum, 1 P. ovale, and 1 P. falciparum plus P. ovale. Moreover, 9 negative samples by microscopy were positive by sn-PCR. Follow-up analysis demonstrated a parasite clearance of P. falciparum DNA up to 3 days after the disappearance of parasitemia at microscopy. In conclusion, sn-PCR-based diagnosis of malaria appears to be a useful tool when the results of conventional techniques are negative in the presence of a syndrome consistent with malaria, yielding accurate species identification and consequential correct treatment.

Diagnosis and therapy for hospitalized imported malaria in adults in Italy

BACKGROUND

The diagnosis and treatment of malaria in non-endemic countries presents a continuing challenge.

METHODS

Medical records were reviewed for 291 patients hospitalized with microscopically confirmed malaria diagnosed consecutively in two infectious diseases wards in Milano, Italy, between 1998 and 2007.

RESULTS

One hundred eighty-six (64%) were male; median age was 35 y (range 16-72 y). Of the 291 patients, 204 (70.1%) were non-immune travelers and 87 (29.9%) were considered semi-immune. In 228 patients (78.3%), Plasmodium falciparum was identified as the only causative malarial parasite. In 48 (16.5%), 9 (3.1%), and 1 (0.3%) cases, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae were diagnosed, respectively. Five mixed infections were observed (1.7%). Of the 233 falciparum cases (including mixed infections), 222 (95.3%) were acquired in sub-Saharan Africa. Fifty-four percent of P vivax infection were acquired in the Indian subcontinent and Southeast Asia. Chemoprophylaxis was used by 23.6% (61/258) subjects with only 32 fully compliant with the recommended regimen. At admission, fever, chills, and headache were present in 95.5, 59.5, and 55.3% of cases, respectively. Elevated serum lactate dehydrogenase levels (95%) and thrombocytopenia (82%) were the most frequently detected laboratory abnormalities. Thirty-five patients (15%) with P falciparum malaria presented with severe malaria according to the WHO criteria; in 19 patients (54.3%) more than one criteria was present. All patients recovered uneventfully. Inappropriate anti-malarial treatment occurred in 25 patients (8.6%) and were recorded more frequently among patients with a diagnosis of P vivax malaria (29.1%) as opposed to those affected by P falciparum (3.9%).

CONCLUSIONS

In our study more than two thirds of imported malaria cases were due to P falciparum with an excess of cases diagnosed in immigrants starting from the year 2000. Despite many available guidelines inappropriate initial malaria treatment is relatively frequent even when patients are managed in an infectious diseases ward.

Evaluation of the Clearview® Malaria pLDH Malaria Rapid Diagnostic Test in a non-endemic setting

Background

Malaria Rapid Diagnostic Tests (RDTs) are widely used to diagnose malaria. The present study evaluated a new RDT, the Clearview^® Malaria pLDH test targeting the pan-Plasmodium antigen lactate dehydrogenase (pLDH).

Methods

The Clearview^® Malaria pLDH test was evaluated on fresh samples obtained in returned international travellers using microscopy corrected by PCR as the reference method. Included samples were Plasmodium falciparum (139), Plasmodium vivax (22), Plasmodium ovale (20), Plasmodium malariae (7), and 102 negative.

Results

Overall sensitivity for the detection of Plasmodium spp was 93.2%. For P. falciparum, the sensitivity was 98.6%; for P. vivax, P. ovale and P. malariae, overall sensitivities were 90.9%, 60.0% and 85.7% respectively. For P. falciparum and for P. vivax, the sensitivities increased to 100% at parasite densities above 100/μl. The specificity was 100%. The test was easily to perform and the result was stable for at least 1 hour.

Conclusion

The Clearview^® Malaria pLDH was efficient for the diagnosis of malaria. The test was very sensitive for P. falciparum and P. vivax detection. The sensitivities for P. ovale and P. malariae were better than other RDTs

Pediatric travelers visiting friends and relatives (VFR) abroad: illnesses, barriers and pre-travel recommendations

Global mobility has shown a steady rise in recent years, with increased immigration and international travel. The VFR traveler is a traveler whose primary purpose of travel is to visit friends and relatives (VFR), where there is a gradient of risk between home and destination. Children are more likely to be VFR travelers than adults. Pediatric VFR travelers have higher risks for certain infectious travel-related illnesses and face multiple barriers in receiving comprehensive pre-travel care. This review focuses on the current state of knowledge of the pediatric VFR traveler, including epidemiological risks, barriers to adequate pre-travel services, and specific recommendations for disease prevention.

Severe imported falciparum malaria: a cohort study in 400 critically ill adults

Background

Large studies on severe imported malaria in non-endemic industrialized countries are lacking. We sought to describe the clinical spectrum of severe imported malaria in French adults and to identify risk factors for mortality at admission to the intensive care unit.

Methodology and Principal Findings

Retrospective review of severe Plasmodium falciparum malaria episodes according to the 2000 World Health Organization definition and requiring admission to the intensive care unit. Data were collected from medical charts using standardised case-report forms, in 45 French intensive care units in 2000–2006. Risk factors for in-hospital mortality were identified by univariate and multivariate analyses.

Data from 400 adults admitted to the intensive care unit were analysed, representing the largest series of severe imported malaria to date. Median age was 45 years; 60% of patients were white, 96% acquired the disease in sub-Saharan Africa, and 65% had not taken antimalarial chemoprophylaxis. Curative quinine treatment was used in 97% of patients. Intensive care unit mortality was 10.5% (42 deaths). By multivariate analysis, three variables at intensive care unit admission were independently associated with hospital death: older age (per 10-year increment, odds ratio [OR], 1.72; 95% confidence interval [95%CI], 1.28–2.32; P = 0.0004), Glasgow Coma Scale score (per 1-point decrease, OR, 1.32; 95%CI, 1.20–1.45; P<0.0001), and higher parasitemia (per 5% increment, OR, 1.41; 95%CI, 1.22–1.62; P<0.0001).

Conclusions and Significance

In a large population of adults treated in a non-endemic industrialized country, severe malaria still carried a high mortality rate. Our data, including predictors of death, can probably be generalized to other non-endemic countries where high-quality healthcare is available.