Imported malaria among people who travel to visit friends and relatives: is current UK policy effective or does it need a strategic change?

Imported malaria: A 20-year retrospective study from a tertiary public hospital in Brussels, Belgium

BACKGROUND

Malaria continues to cause a significant number of infections in non-endemic regions. In this paper, we describe the epidemiological trend and morbidity of imported malaria diagnosed in a tertiary hospital in Brussels.

METHODS

We conducted a retrospective study describing a cohort of malaria episodes (in- and outpatients) at Centre Hospitalier Universitaire Saint-Pierre from 1998 to 2017. Epidemiological and clinical data were collected by reviewing medical files.

RESULTS

A total of 1011 malaria episodes were analyzed. Median age at diagnosis was 35 years, and 66 % of patients were men (672/1011). Malaria cases significantly increased over the two decades (from 17 in 1998 to 79 in 2017). Plasmodium falciparum malaria was most often diagnosed (846/935, 89 %), primarily from Central (530/935, 57 %) and West Africa (324/935, 35 %). Many cases (383/764, 50 %) were diagnosed in patients "visiting friends and relatives". HIV-infected and other immunocompromised patients were significantly more likely to present with severe malaria (at least one severity criteria as defined by the WHO) compared to other patients (24/57, 42 % vs 138/732, 19 %, p < 0.01 and 15/21, 71 % vs 147/767, 19 %, p < 0.001). Severe malaria was diagnosed in 16.9 % and the mortality rate was low (5/1011, 0.5 %).

CONCLUSION

Imported malaria increased over the years with a large, albeit stable number of cases diagnosed in patients visiting friends and relatives. These findings, along with the high rate of severe malaria in HIV and immunocompromised patients, underscore an urgent need for strengthened malaria surveillance and targeted preventive interventions.

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.

Evaluation of an Innovative Point-of-Care Rapid Diagnostic Test for the Identification of Imported Malaria Parasites in China

BACKGROUND

China was certified malaria-free by the World Health Organization on 30 June 2021. However, due to imported malaria, maintaining a malaria-free status in China is an ongoing challenge. There are critical gaps in the detection of imported malaria through the currently available tools, especially for non-falciparum malaria. In the study, a novel point-of-care Rapid Diagnostic Test designed for the detection of imported malaria infections was evaluated in the field.

METHODS

Suspected imported malaria cases reported from Guangxi and Anhui Provinces of China during 2018-2019 were enrolled to evaluate the novel RDTs. Diagnostic performance of the novel RDTs was evaluated based on its sensitivity, specificity, positive and negative predictive values, and Cohen's kappa coefficient, using polymerase chain reaction as the gold standard. The Additive and absolute Net Reclassification Index were calculated to compare the diagnostic performance between the novel RDTs and Wondfo RDTs (control group).

RESULTS

A total of 602 samples were tested using the novel RDTs. Compared to the results of PCR, the novel RDTs presented sensitivity, specificity, PPV, NPV, and diagnostic accuracy rates of 78.37%, 95.05%, 94.70%, 79.59%, and 86.21%, respectively. Among the positive samples, the novel RDTs found 87.01%, 71.31%, 81.82%, and 61.54% of P. falciparum, P. ovale, P. vivax, and P. malariae, respectively. The ability to detect non-falciparum malaria did not differ significantly between the novel and Wondfo RDTs (control group). However, Wondfo RDTs can detect more P. falciparum cases than the novel RDTs (96.10% vs. 87.01%, p < 0.001). After the introduction of the novel RDTs, the value of the additive and absolute Net Reclassification Index is 1.83% and 1.33%, respectively.

CONCLUSIONS

The novel RDTs demonstrated the ability to distinguish P. ovale and P. malariae from P. vivax which may help to improve the malaria post-elimination surveillance tools in China.

Imported malaria definition and minimum data for surveillance

The mobility of malaria-infected individuals poses challenges to elimination campaigns by way of spreading parasite drug resistance, straining country-to-country collaboration, and making routine data collection difficult, especially in resource-poor settings. Nevertheless, no concerted effort has been made to develop a common framework to define the spatial and temporal components of an imported malaria case and recommend the minimum data needed to identify it. We conducted a scoping review of imported malaria literature from 2010 to 2020 which showed that definitions vary widely, and local capabilities of detecting importation are often restricted in low-income countries. Following this, we propose a common definition for imported malaria and the minimum data required to identify a case, depending on the country's capability of conducting an epidemiological investigation. Lastly, we utilize the proposed definition using data from Brazil to demonstrate both the feasibility and the importance of tracking imported cases. The case of Brazil highlights the capabilities of regular surveillance systems to monitor importation, but also the need to regularly use these data for informing local responses. Supporting countries to use regularly collected data and adopt a common definition is paramount to tackling the importation of malaria cases and achieving elimination goals set forth by the World Health Organization.

Epidemiology and clinical features of imported malaria: a 14-year retrospective single-centre descriptive study in Prague, Czech Republic

Background

Malaria represents one of the most important imported tropical infectious diseases in European travellers. The objective of the study was to identify changes in the epidemiological features of imported malaria and to analyse the clinical findings and outcomes of imported malaria.

Methods

This single-centre descriptive study retrospectively analysed the medical records of all imported malaria cases in travellers treated at the Department of Infectious Diseases of University Hospital Bulovka in Prague from 2006 to 2019.

Results

The study included 203 patients with a median age of 37 years (IQR 30–48) and a male to female ratio of 3.72:1. Plasmodium falciparum was the predominant species (149/203), and its proportion significantly increased from 35/60 cases (58.3%) in 2006–2011 to 69/80 (86.3%) in 2016–2019 (p < 0.001). In contrast, the incidence of Plasmodium vivax malaria decreased from 19/60 cases (31.7%) in 2006–2011 to 5/80 (6.3%) in 2016–2019 (p < 0.001). Malaria was imported from sub-Saharan Africa in 161/203 cases (79.3%). The proportion of travellers from Southeast and South Asia decreased from 16/60 (26.7%) and 6/60 (10.0%) in 2006–2011 to 2/80 (2.5%) and no cases (0.0%) in 2016–2019, respectively (p < 0.001 and p = 0.006). Tourism was the most common reason for travel (82/203), however, the proportion of non-tourists significantly increased over time from 29/60 (48.3%) in 2006–2011 to 55/80 (68.8%) in 2016–2019, p = 0.015. Severe malaria developed in 32/203 (15.8%) patients who were significantly older (p = 0.013) and whose treatment was delayed (p < 0.001). Two lethal outcomes were observed during the study period.

Conclusions

This study demonstrated a significant increase in P. falciparum malaria, which frequently resulted in severe disease, especially in older patients and those with delayed treatment initiation. The rising proportion of imported malaria in non-tourists, including business travellers and those visiting friends and relatives, is another characteristic finding analogous to the trends observed in Western European and North American centres. The described changes in the aetiology and epidemiology of imported malaria may serve to optimize pre-travel consultation practices and improve post-travel diagnostics and medical care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04282-8.

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.

Where was my patient born? The Intersection of tropical medicine and migrant health

PURPOSE OF REVIEW

There is unprecedented movement of people across international borders and parasitic infections, previously restricted to endemic regions, are now encountered in nonendemic areas of the world.

RECENT FINDINGS

Migrants may import parasitic infections acquired in their countries of origin. Increasingly, clinicians in nonendemic regions are faced with patients with neglected diseases such as Chagas disease, malaria and strongyloidiasis. There are gaps in knowledge among physicians in nonendemic regions, which lead to missed opportunities for preventive strategies and early treatment. Both primary care and infectious disease physicians should have a broad knowledge of common parasitic infections to improve health outcomes and decrease healthcare disparities through early identification and treatment of disease encountered in migrants.

SUMMARY

Migrant health is still a young field in medicine; clinicians should be aware of diseases seen in migrants, and access both educational and clinical resources, including experts in tropical medicine, in order to reduce health disparities among migrants. Collaboration between primary care and infectious disease/tropical medicine experts should be strengthened.

Fifty years after the eradication of Malaria in Italy. The long pathway toward this great goal and the current health risks of imported malaria

Fifty years ago, Italy was declared a malaria-free country by the World Health Organization (WHO). In remembering this important anniversary, the authors of this paper describe the long journey that led to this goal. In the century following the unification of Italy, malaria was one of the main public health problems. At the end of the 19th century, malaria cases amounted to 2 million, with 15,000-20,000 deaths per year. This manuscript examines the state of public and social health in Italy from the end of the 19th century to the beginning of the 20th century, with particular regard to the government's measures for the prevention, prophylaxis and treatment of malaria. The authors describe the main findings of Italian malariologists during the period under review, from the identification of Plasmodium as a malaria pathogen and the recognition of the Anopheles mosquito as its vector. They also make some considerations regarding the current situation and the importation of malaria by travelers and migrants from countries where the disease is still endemic.

Persistence of Imported Malaria Into the United Kingdom: An Epidemiological Review of Risk Factors and At-risk Groups

BACKGROUND

The United Kingdom documented a decline of >30% in imported cases of malaria annually between 1996 and 2003; however, there are still approximately 1700 cases and 5-10 deaths each year. Prophylaxis health messages focus on families returning to their country of origin.

METHODS

We reviewed 225 records of patients seen in Cambridge University Hospital Foundation Trust [CUHFT], a tertiary referral center in Cambridge, England. All records of patients seen in CUHFT between 2002-2016 were analyzed in the context of national figures from Public Health England.

RESULTS

Between 2004-2016, there was no decrease in imported cases of malaria locally or nationally. Plasmodium falciparum remains responsible for most imported infections (66.7%); Plasmodium vivax contributed 15.1%, Plasmodium malariae 4%, and Plasmodium ovale 6.7%; 7.5% (17/225) of patients had an incomplete record. Most cases were reported in people coming from West Africa. Sierra Leone and the Ivory Coast had the highest proportions of travelers being infected at 8 and 7 per 1000, respectively. Visiting family in the country of origin (27.8%) was the commonest reason for travel. However, this was exceeded by the combined numbers traveling for business and holidays (22.5% and 20.1%, respectively). Sixty percent of patients took no prophylaxis. Of those who did, none of the patients finished their chemoprophylaxis regimen.

CONCLUSIONS

Significant numbers of travelers to malarious countries still take no chemoprophylaxis. Health advice about prophylaxis before travel should be targeted not only at those visiting family in their country of origin but also to those traveling for holiday and work.

Severity of Plasmodium falciparum and Non-falciparum Malaria in Travelers and Migrants: A Nationwide Observational Study Over 2 Decades in Sweden

Background

The aim was to assess factors affecting disease severity in imported P. falciparum and non-falciparum malaria.

Methods

We reviewed medical records from 2793/3260 (85.7%) of all episodes notified in Sweden between 1995 and 2015 and performed multivariable logistic regression.

Results

Severe malaria according to WHO 2015 criteria was found in P. falciparum (9.4%), P. vivax (7.7%), P. ovale (5.3%), P. malariae (3.3%), and mixed P. falciparum episodes (21.1%). Factors associated with severe P. falciparum malaria were age <5 years and >40 years, origin in nonendemic country, pregnancy, HIV, region of diagnosis, and health care delay. Moreover, oral treatment of P. falciparum episodes with parasitemia ≥2% without severe signs at presentation was associated with progress to severe malaria with selected criteria. In non-falciparum, age >60 years, health care delay and endemic origin were identified as risk factors for severe disease. Among patients originating in endemic countries, a higher risk for severe malaria, both P. falciparum and non-falciparum, was observed among newly arrived migrants.

Conclusions

Severe malaria was observed in P. falciparum and non-falciparum episodes. Current WHO criteria for severe malaria may need optimization to better guide the management of malaria of different species in travelers and migrants in nonendemic areas.

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.

Fever in travellers returning from the tropics

The increase in international travel, the growing presence of arbovirus vectors in our country, and notifications of haemorrhagic fever such as the current outbreak of Ebola in D.R. Congo and the cases of Crimea-Congo haemorrhagic fever in our country have again cast the spotlight on tropical diseases. Isolating suspected cases of highly contagious and lethal diseases must be a priority (haemorrhagic fever, MERS-CoV). Assessing the patient, taking a careful medical history based on epidemiological aspects of the area of origin, activities they have carried out, their length of stay in the area and the onset of symptoms, will eventually help us, if not to make a definitive diagnosis, at least to exclude diseases that pose a threat to these patients. Malaria should be ruled out because of its frequency, without forgetting other common causes of fever familiar to emergency doctors.

Fever in travellers returning from the tropics

The increase in international travel, the growing presence of arbovirus vectors in our country, and notifications of haemorrhagic fever such as the current outbreak of Ebola in D.R. Congo and the cases of Crimea-Congo haemorrhagic fever in our country have again cast the spotlight on tropical diseases Isolating suspected cases of highly contagious and lethal diseases must be a priority (Haemorrhagic fever, MERS-CoV). Assessing the patient, taking a careful medical history based on epidemiological aspects of the area of origin, activities they have carried out, their length of stay in the area and the onset of symptoms, will eventually help us, if not to make a definitive diagnosis, at least to exclude diseases that pose a threat to these patients. Malaria should be ruled out because of its frequency, without forgetting other common causes of fever familiar to emergency doctors.

New guidelines for the prevention of imported malaria in France

Prevention of malaria is based on personal vector-control measures (PVCMs) to avoid mosquito bites at night and chemoprophylaxis if justified by the risk of contracting the disease. The most effective PVCM is the use of insecticide-treated mosquito nets. The decision to prescribe chemoprophylaxis, mainly to prevent Plasmodium falciparum infection, depends on the benefit-risk ratio. Overall, the risk of contracting malaria is 1,000-fold lower during a stay in the tropical regions of Asia or the Americas than in sub-Saharan Africa. For "conventional" stays (less than one month with nights spent in urban areas) in low-risk settings in tropical Asia and America, the risk of being infected with Plasmodium parasites (≤1/100,000) is equivalent or lower than that of experiencing serious adverse effects caused by chemoprophylaxis. Preventive medication is therefore no longer recommended. By contrast, in other settings and particularly in sub-Saharan Africa, chemoprophylaxis is the most effective measure against malaria. However, it is worth noting that no single preventive measure provides full protection. Regardless of the level of risk or chemoprophylaxis-related indication, protection against mosquito bites and rapid management of febrile illness after returning from an endemic area are also critical to prevent malaria. Finally, migrants of sub-Saharan origin visiting friends and relatives in their country of origin form a high-risk group who should be recommended chemoprophylaxis in the same way as any other travelers-with a preference for the least expensive molecules (doxycycline).

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.

Acute interstitial nephritis with podocyte foot-process effacement complicating Plasmodium falciparum infection

Background

Malarial acute renal failure (MARF) is a component of the severe malaria syndrome, and complicates 1–5% of malaria infections. This form of renal failure has not been well characterized by histopathology.

Case presentation

A 44 year-old male presented to the emergency department with a 5-day history of fever and malaise after returning from Nigeria. A blood film was positive for Plasmodium falciparum. His creatinine was 616 µmol/L coming from a normal baseline of 89 µmol/L. He had a urine protein:creatinine ratio of 346 mg/mmol (4.4 g/L). He required dialysis. A renal biopsy showed acute interstitial nephritis with podocyte foot-process effacement. He was treated with artesunate and his renal function improved. At 1 year follow-up his creatinine had plateaued at 120 µmol/L with persistent low-grade proteinuria.

Conclusion

Acute interstitial nephritis and podocyte foot-process effacement might be under-recognized lesions in MARF. Studying the mechanisms of MARF could give insight into the immunopathology of severe malaria.

Photo-based External Quality Assessment of Malaria rapid diagnostic tests in a non-endemic setting

Introduction

In non-endemic settings, expertise in malaria microscopy is limited and rapid diagnostic tests (RDTs) are an adjunct to malaria diagnosis.

Aim

We performed an External Quality Assessment (EQA) on reading and interpretation of malaria RDTs in a non-endemic setting.

Methods

Participants were medical laboratories in Belgium and the Grand Duchy of Luxembourg using malaria RDTs; they received (i) 10 high-resolution photographs presenting test line combinations of RDTs with interpretations listed in a multiple choice format and (ii) a questionnaire about their practices of malaria diagnosis.

Results

Among 135 subscribing laboratories, 134 (99.3%) used 139 RDT products (11 different products from 8 brands). After exclusion of the results of one laboratory, analysis was done for 133 laboratories using 137 RDT products. Scores of 10/10, 9/10 and 8/10 were achieved for 58.4%, 13.1% and 8.0% of 137 RDT products respectively. For three-band P. falciparum–pan-Plasmodium RDTs (113 (82.5%) products, 6 brands), most frequent errors were (1) disregarding faint test lines (18.6%), (2) reporting invalid instead of P. falciparum (16.8%) and (3) reporting “Plasmodium spp., no further differentiation possible” without mentioning the presence or absence of P. falciparum (11.5%). For four-band RDTs (21 (15.3%) products, 1 brand), errors were (4) disregarding faint P. vivax test lines (47.6%) and (5) reporting “Plasmodium spp., no further differentiation possible” without mentioning the presence of P. falciparum and P. vivax (28.6%). Instructions for use (IFU) of only 4 out of 10 RDT products mentioned to interpret faint-intensity test lines as positive (conducive to errors 1 and 4) and IFU of 2 products displayed incorrect information (conducive to errors 2 and 5). Outside of office hours, 36.1% of participants relied on RDTs as the initial diagnostic test; 13.9% did not perform microscopic confirmation.

Conclusion

Reading and interpretation of malaria RDTs was satisfactory, but errors were embedded in the instructions for use of the products. Relying on RDTs alone for malaria diagnosis (about one third of participants) is not a recommended practice.

Status of imported malaria on Réunion Island in 2016

BACKGROUND

Autochthonous malaria has been eliminated from Réunion in 1979. To prevent secondary transmission and re-emergence of autochthonous malaria, permanent epidemiologic and entomological surveillance and vector control measures are conducted around imported malaria cases. Results of local malaria surveillance (clinical data and results of epidemiological and entomological investigations around cases) were collected for 2013-2016 and were analysed according to historical data and to the exchanges with malaria-affected areas (estimated by airport data).

RESULTS

Form 2013 to 2016, 95 imported malaria cases have been detected in Reunion Island: 42% of cases occurred in the area of repartition of Anopheles arabiensis, but Anopheles mosquitoes were present only around seven cases including one gametocyte carrier. No autochthonous or introduced case has occurred during this period. The lack of chemoprophylaxis or poor adherence was found in the majority (96%) of malaria cases between 2013 and 2016, regardless of trip type. Affinity tourism in Madagascar and Comoros was the cause of 65% of imported malaria cases.

DISCUSSION

The incidence of imported malaria and the incidence rate per 100,000 travellers has continuously decreased since 2001. Now with the drastic decrease of malaria transmission in the Comoros archipelago, most of imported malaria cases in Reunion Island have been contaminated in Madagascar. Immigrants regularly resident in Reunion Island, which travel to malaria endemic countries (mainly Madagascar) to visit their friends and relatives (VFRs) represent a high-risk group of contracting malaria. VFRs, low adherence to pre-travel recommendations, in particular, the compliance on the use of chemoprophylaxis are the main drivers of imported malaria in Reunion Island. Furthermore as previously described, some general practitioners in Reunion Island are always not sufficiently aware of the official recommendations for prescriptions of prophylactic treatments.

CONCLUSION

Social mobilization targeted on the Malagasy community in Reunion Island could help to decrease the burden of imported malaria in Reunion Island. Because of the low number of gametocyte carriers and the absence of an Anopheles mosquito population when most malaria cases were imported those last 4 years, the risk of the appearance of introduced malaria cases and indigenous malaria cases appears low in Reunion Island.

Imported malaria in Bulgaria, status and prognosis after eradication in 1965

BACKGROUND

This retrospective analysis assessed all recorded malaria cases in Bulgaria after 1965, when the country was certified as malaria-free by the World Health Organization (WHO), and evaluated the readiness of the public health system to interrupt an outbreak of local transmission in case of infection importation.

METHODS

The cases were analyzed according to causative species; geographic origin of the imported case; and the citizenship, age, and gender of the infected individuals.

RESULTS

In the 50-year study period (1966-2015), there were a total of 3011 cases of malaria imported to Bulgaria from different regions of the world. The majority of the cases originating in Africa were caused by Plasmodium falciparum (65.5%), while most of these originating in Asia were caused by P. vivax (80.9%). The potential season for malaria transmission in Bulgaria is from April to October, and 58.5% of the malaria cases were imported during that time of the year.

CONCLUSIONS

The increasing movement of people to and from areas endemic for malaria requires the health authorities of countries with appropriate conditions for reintroduction to conduct enhanced measures for surveillance and control of this potentially deadly disease.

Epidemiology of Imported Malaria Cases in Japan, 2006-2014: A Sentinel Traveler Surveillance Approach

Malaria continues to be imported into Japan. To better assess the risk of imported malaria, we describe malaria species, suspected country/area of infection (accounting for the number of travelers), demographic characteristics, clinical manifestation, and healthcare access, based on the national surveillance data from 2006 to 2014. Among 557 cases, the median age was 33 years (range: 1-83 years), and 76% were male; 306 (55%) were classified as Japanese based on the reported name. The majority were Plasmodium falciparum infections (58%), followed by Plasmodium vivax infections (30%). Most P. falciparum cases were acquired in Africa and P. vivax in Asia/Oceania. Notification rates per 10,000 Japanese travelers for P. falciparum were highest for Africa, P. vivax were highest for Asia/Oceania, and high for both species for Papua New Guinea. Ten percent of the cases were clinically severe at the time of notification. Nearly 80% of severe cases were P. falciparum infections, and among P. falciparum cases, Japanese ethnicity was associated with severe case status (P = 0.03). Plasmodium falciparum cases among Japanese cases showed that older age (≥ 50 years) was associated with severe case status (odds ratio = 5.4; 95% confidence interval = 1.9-15.2), adjusted for sex and healthcare access. More informative assessments are possible by accounting for the number of travelers. Older Japanese represent an important demographic to target prevention and early treatment efforts for malaria.

Mefloquine for preventing malaria during travel to endemic areas

BACKGROUND

Mefloquine is one of four antimalarial agents commonly recommended for preventing malaria in travellers to malaria-endemic areas. Despite its high efficacy, there is controversy about its psychological side effects.

OBJECTIVES

To summarize the efficacy and safety of mefloquine used as prophylaxis for malaria in travellers.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published on the Cochrane Library; MEDLINE; Embase (OVID); TOXLINE (https://toxnet.nlm.nih.gov/newtoxnet/toxline.htm); and LILACS. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP; http://www.who.int/ictrp/en/) and ClinicalTrials.gov (https://clinicaltrials.gov/ct2/home) for trials in progress, using 'mefloquine', 'Lariam', and 'malaria' as search terms. The search date was 22 June 2017.

SELECTION CRITERIA

We included randomized controlled trials (for efficacy and safety) and non-randomized cohort studies (for safety). We compared prophylactic mefloquine with placebo, no treatment, or an alternative recommended antimalarial agent. Our study populations included all adults and children, including pregnant women.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and risk of bias of trials, extracted and analysed data. We compared dichotomous outcomes using risk ratios (RR) with 95% confidence intervals (CI). Prespecified adverse outcomes are included in 'Summary of findings' tables, with the best available estimate of the absolute frequency of each outcome in short-term international travellers. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 20 RCTs (11,470 participants); 35 cohort studies (198,493 participants); and four large retrospective analyses of health records (800,652 participants). Nine RCTs explicitly excluded participants with a psychiatric history, and 25 cohort studies stated that the choice of antimalarial agent was based on medical history and personal preference. Most RCTs and cohort studies collected data on self-reported or clinician-assessed symptoms, rather than formal medical diagnoses. Mefloquine efficacyOf 12 trials comparing mefloquine and placebo, none were performed in short-term international travellers, and most populations had a degree of immunity to malaria. The percentage of people developing a malaria episode in the control arm varied from 1% to 82% (median 22%) and 0% to 13% in the mefloquine group (median 1%).In four RCTs that directly compared mefloquine, atovaquone-proguanil and doxycycline in non-immune, short-term international travellers, only one clinical case of malaria occurred (4 trials, 1822 participants). Mefloquine safety versus atovaquone-proguanil Participants receiving mefloquine were more likely to discontinue their medication due to adverse effects than atovaquone-proguanil users (RR 2.86, 95% CI 1.53 to 5.31; 3 RCTs, 1438 participants; high-certainty evidence). There were few serious adverse effects reported with mefloquine (15/2651 travellers) and none with atovaquone-proguanil (940 travellers).One RCT and six cohort studies reported on our prespecified adverse effects. In the RCT with short-term travellers, mefloquine users were more likely to report abnormal dreams (RR 2.04, 95% CI 1.37 to 3.04, moderate-certainty evidence), insomnia (RR 4.42, 95% CI 2.56 to 7.64, moderate-certainty evidence), anxiety (RR 6.12, 95% CI 1.82 to 20.66, moderate-certainty evidence), and depressed mood during travel (RR 5.78, 95% CI 1.71 to 19.61, moderate-certainty evidence). The cohort studies in longer-term travellers were consistent with this finding but most had larger effect sizes. Mefloquine users were also more likely to report nausea (high-certainty evidence) and dizziness (high-certainty evidence).Based on the available evidence, our best estimates of absolute effect sizes for mefloquine versus atovaquone-proguanil are 6% versus 2% for discontinuation of the drug, 13% versus 3% for insomnia, 14% versus 7% for abnormal dreams, 6% versus 1% for anxiety, and 6% versus 1% for depressed mood. Mefloquine safety versus doxycyclineNo difference was found in numbers of serious adverse effects with mefloquine and doxycycline (low-certainty evidence) or numbers of discontinuations due to adverse effects (RR 1.08, 95% CI 0.41 to 2.87; 4 RCTs, 763 participants; low-certainty evidence).Six cohort studies in longer-term occupational travellers reported our prespecified adverse effects; one RCT in military personnel and one cohort study in short-term travellers reported adverse events. Mefloquine users were more likely to report abnormal dreams (RR 10.49, 95% CI 3.79 to 29.10; 4 cohort studies, 2588 participants, very low-certainty evidence), insomnia (RR 4.14, 95% CI 1.19 to 14.44; 4 cohort studies, 3212 participants, very low-certainty evidence), anxiety (RR 18.04, 95% CI 9.32 to 34.93; 3 cohort studies, 2559 participants, very low-certainty evidence), and depressed mood (RR 11.43, 95% CI 5.21 to 25.07; 2 cohort studies, 2445 participants, very low-certainty evidence). The findings of the single cohort study reporting adverse events in short-term international travellers were consistent with this finding but the single RCT in military personnel did not demonstrate a difference between groups in frequencies of abnormal dreams or insomnia.Mefloquine users were less likely to report dyspepsia (RR 0.26, 95% CI 0.09 to 0.74; 5 cohort studies, 5104 participants, low certainty-evidence), photosensitivity (RR 0.08, 95% CI 0.05 to 0.11; 2 cohort studies, 1875 participants, very low-certainty evidence), vomiting (RR 0.18, 95% CI 0.12 to 0.27; 4 cohort studies, 5071 participants, very low-certainty evidence), and vaginal thrush (RR 0.10, 95% CI 0.06 to 0.16; 1 cohort study, 1761 participants, very low-certainty evidence).Based on the available evidence, our best estimates of absolute effect for mefloquine versus doxycyline were: 2% versus 2% for discontinuation, 12% versus 3% for insomnia, 31% versus 3% for abnormal dreams, 18% versus 1% for anxiety, 11% versus 1% for depressed mood, 4% versus 14% for dyspepsia, 2% versus 19% for photosensitivity, 1% versus 5% for vomiting, and 2% versus 16% for vaginal thrush.Additional analyses, including comparisons of mefloquine with chloroquine, added no new information. Subgroup analysis by study design, duration of travel, and military versus non-military participants, provided no conclusive findings.

AUTHORS' CONCLUSIONS

The absolute risk of malaria during short-term travel appears low with all three established antimalarial agents (mefloquine, doxycycline, and atovaquone-proguanil).The choice of antimalarial agent depends on how individual travellers assess the importance of specific adverse effects, pill burden, and cost. Some travellers will prefer mefloquine for its once-weekly regimen, but this should be balanced against the increased frequency of abnormal dreams, anxiety, insomnia, and depressed mood.

Malaria after international travel: a GeoSentinel analysis, 2003-2016

BACKGROUND

More than 30,000 malaria cases are reported annually among international travellers. Despite improvements in malaria control, malaria continues to threaten travellers due to inaccurate perception of risk and sub-optimal pre-travel preparation.

METHODS

Records with a confirmed malaria diagnosis after travel from January 2003 to July 2016 were obtained from GeoSentinel, a global surveillance network of travel and tropical medicine providers that monitors travel-related morbidity. Records were excluded if exposure country was missing or unascertainable or if there was a concomitant acute diagnosis unrelated to malaria. Records were analyzed to describe the demographic and clinical characteristics of international travellers with malaria.

RESULTS

There were 5689 travellers included; 325 were children <18 years. More than half (53%) were visiting friends and relatives (VFRs). Most (83%) were exposed in sub-Saharan Africa. The median trip duration was 32 days (interquartile range 20-75); 53% did not have a pre-travel visit. More than half (62%) were hospitalized; children were hospitalized more frequently than adults (73 and 62%, respectively). Ninety-two per cent had a single Plasmodium species diagnosis, most frequently Plasmodium falciparum (4011; 76%). Travellers with P. falciparum were most frequently VFRs (60%). More than 40% of travellers with a trip duration ≤7 days had Plasmodium vivax. There were 444 (8%) travellers with severe malaria; 31 children had severe malaria. Twelve travellers died.

CONCLUSION

Malaria remains a serious threat to international travellers. Efforts must focus on preventive strategies aimed on children and VFRs, and chemoprophylaxis access and preventive measure adherence should be emphasized.

Pre-travel advice at a crossroad: Medical preparedness of travellers to South and Southeast-Asia - The Hamburg Airport Survey

BACKGROUND

Specific travel-related recommendations exist for the prevention or self-treatment of infectious diseases contracted by travellers to the tropics. In the current study, we assessed the medical preparedness per these recommendations, focusing on whether travellers carried antidiarrheal and antimalarial medication with them stratified by type of pre-travel advice.

METHODS

We surveyed travellers departing from Hamburg International Airport to South or Southeast Asia, using a questionnaire on demographic, medical and travel characteristics.

RESULTS

975 travellers were analysed - the majority (817, 83%) being tourists. A large proportion packed any antidiarrheal medication (612, 63%) - most frequently loperamide (440, 72%). Only 176 of 928 (19%) travellers to destinations with low-to medium risk for malaria packed a recommended antimalarial medication. The majority (162, 17%) of them carried antimalarials as stand-by emergency treatment (SBET). 468 (48%) travellers had a pre-travel medical consultation. This lead to higher odds of carrying SBET- with the highest odds associated with a consultation at a travel medicine specialist (OR 7.83 compared to no consultation).

CONCLUSIONS

Attending a travel medicine specialist was associated with better adherence to current recommendations concerning the carriage of stand-by emergency treatment of malaria. However, the proportion of travellers seeking pre-travel health advice was overall low in our population. Promoting pre-travel consultations may, therefore, lead to higher adherence to the current recommendations in travel medicine.

A study on the epidemiological characteristics and infectious forecast model of malaria at Guangzhou Airport among Chinese returnees from Africa

BACKGROUND

Cross-border malaria transmission in China is a major component of Chinese imported malaria cases. Such cases mostly are travellers returning from malaria endemic countries in Africa. By investigating malaria infectious status among Chinese worker in Africa, this study analysed the malaria risk factors, in order to establish infectious forecast model.

METHODS

Chinese returnees data from Africa were collected at Guangzhou Baiyun International Airport, Guangzhou, China between August 2015 and March 2016 and were included in the cross-sectional and retrospective survey.

RESULTS

A total of 1492 respondents were included in the study with the majority consisting of junior middle school educated male. Most of them are manual and technical workers hired by companies, with average of 37.04 years of age. Overall malaria incidence rate of the population was 8.98% (134/1492), and there were no significant differences regarding age, gender, occupation, or team. Forecast model was developed on the basis of malaria risk factors including working country, local ecological environment type, work duration and intensity of mosquito bite prevention.

CONCLUSIONS

The survey suggested that malaria incidence was high among Chinese travellers who had worked in Africa countries of heavy malaria burden. Further research on the frequency and severity of clinical episodes among Chinese travellers having worked in Africa is needed.

Assessment of the French National Health Insurance Information System as a tool for epidemiological surveillance of malaria

OBJECTIVE

Epidemiological surveillance of malaria in France is based on a hospital laboratory sentinel surveillance network. There is no comprehensive population surveillance. The objective of this study was to assess the ability of the French National Health Insurance Information System to support nationwide malaria surveillance in continental France.

MATERIALS AND METHODS

A case identification algorithm was built in a 2-step process. First, inclusion rules giving priority to sensitivity were defined. Then, based on data description, exclusion rules to increase specificity were applied. To validate our results, we compared them to data from the French National Reference Center for Malaria on case counts, distribution within subgroups, and disease onset date trends.

RESULTS

We built a reusable automatized tool. From July 1, 2013, to June 30, 2014, we identified 4077 incident malaria cases that occurred in continental France. Our algorithm provided data for hospitalized patients, patients treated by private physicians, and outpatients for the entire population. Our results were similar to those of the National Reference Center for Malaria for each of the outcome criteria.

DISCUSSION

We provided a reliable algorithm for implementing epidemiological surveillance of malaria based on the French National Health Insurance Information System. Our method allowed us to work on the entire population living in continental France, including subpopulations poorly covered by existing surveillance methods.

CONCLUSION

Traditional epidemiological surveillance and the approach presented in this paper are complementary, but a formal validation framework for case identification algorithms is necessary.

Impact of using artemisinin-based combination therapy (ACT) in the treatment of uncomplicated malaria from Plasmodium falciparum in a non-endemic zone

BACKGROUND

Artemisinin-based combination therapy (ACT) has been adopted by the World Health Organization as a first-line treatment for uncomplicated Plasmodium falciparum malaria. In endemic regions, it has proven more effective in treating the disease, and even in reducing its transmission. Nonetheless, there is a scarcity of studies carried out in non-endemic areas on imported uncomplicated malaria.

METHODS

This is a retrospective, observational study performed on patients diagnosed and admitted with uncomplicated P. falciparum malaria between 2004 and 2015. The objective was to compare the parasite clearance period and the average hospital length of stay for patients treated with ACT vs those receiving other treatment regimens.

RESULTS

Eighty-five patients were included in the study. Fifty-one received ACT treatment (dihydroartemisinin-piperaquine) and thirty-four patients were treated with quinine sulfate+doxycycline or atovaquone/proguanil. The parasite clearance period was shorter in the group of patients treated with ACT compared to those receiving other treatment types: 24 h (IQR 24) vs 48 h (IQR 48), p < 0.01. The average hospital stay was also shorter in the ACT group with respect to the second group: 2.67 days (IQR 1.08) vs 3.96 days (IQR 2.87), p < 0.001. A mild case of hepatitis was registered in the group treated with ACT.

CONCLUSIONS

ACT treatment of admitted hospital patients with imported uncomplicated malaria from P. falciparum reduced the days spent hospitalized as well as producing a more rapid parasite clearance compared to classic treatment. In spite of being treated with safe medications, one has to be alert to possible adverse effects such as hepatitis and delayed haemolytic anaemia.

Travel medicine physician adherence to guidelines for the emergency self treatment of malaria

Few studies have examined emergency self treatment (EST) antimalarial prescribing patterns. 110 physician-members of the Travel Medicine Society of Ireland and British Global and Travel Health Association participated in this study. There was a trend towards the prescription of EST for travel to remote low-risk malaria areas; for long-term residents living in low-risk areas; and for frequent travellers to low-risk areas. This study provides insights into the use of EST in travellers' malaria.