Migrants as a major risk group for imported malaria in European countries

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.

Malaria in Italy - Migrants Are Not the Cause

Recently, five cases of malaria were reported in Italy. These people had not travelled abroad, prompting some media and political organizations to fuel a climate of fear by connecting the cases with migrants coming into the country. Here, we discuss scientific data highlighting the limited risk of malaria reintroduction in Italy.

The contribution of travellers visiting friends and relatives to notified infectious diseases in Australia: state-based enhanced surveillance

Immigrants and their children who return to their country of origin to visit friends and relatives (VFR) are at increased risk of acquiring infectious diseases compared to other travellers. VFR travel is an important disease control issue, as one quarter of Australia's population are foreign-born and one quarter of departing Australian international travellers are visiting friends and relatives. We conducted a 1-year prospective enhanced surveillance study in New South Wales and Victoria, Australia to determine the contribution of VFR travel to notifiable diseases associated with travel, including typhoid, paratyphoid, measles, hepatitis A, hepatitis E, malaria and chikungunya. Additional data on characteristics of international travel were collected. Recent international travel was reported by 180/222 (81%) enhanced surveillance cases, including all malaria, chikungunya and paratyphoid cases. The majority of cases who acquired infections during travel were immigrant Australians (96, 53%) or their Australian-born children (43, 24%). VFR travel was reported by 117 (65%) travel-associated cases, highest for typhoid (31/32, 97%). Cases of children (aged <18 years) (86%) were more frequently VFR travellers compared to adult travellers (57%, P < 0·001). VFR travel is an important contributor to imported disease in Australia. Communicable disease control strategies targeting these travellers, such as targeted health promotion, are likely to impact importation of these travel-related infections.

Improving the uptake of pre-travel health advice amongst migrant Australians: exploring the attitudes of primary care providers and migrant community groups

Background

Migrant travellers who return to their country of origin to visit family and friends (VFR) are less likely to seek travel-related medical care and are less likely to adhere to recommended medications and travel precautions. Through this study, we aimed to get an understanding of the views of stakeholders from community migrant centres and primary care providers on barriers for migrants, particularly from non-English speaking backgrounds, in accessing travel health advice and the strategies that could be used to engage them.

Methods

A qualitative study involving 20 semi-structured interviews was undertaken in Sydney, Australia between January 2013 and September 2014. Thematic analysis was undertaken.

Results

Language barriers, a lower perceived risk of travel-related infections and the financial costs of seeking pre-travel health care were nominated as being the key barriers impacting on the uptake of pre-travel health advice and precautions. To overcome pre-existing language barriers, participants advocated for the use of bilingual community educators, community radio, ethnic newspapers and posters in the dissemination of pre-travel health information.

Conclusions

Travel is a major vector of importation of infectious diseases into Australia, and VFR travellers are at high risk of infection. Collaboration between the Government, primary care physicians, migrant community groups and migrants themselves is crucial if we are to be successful in reducing travel-related risks among this subgroup of travellers.

Cross-border malaria: a major obstacle for malaria elimination

Movement of malaria across international borders poses a major obstacle to achieving malaria elimination in the 34 countries that have committed to this goal. In border areas, malaria prevalence is often higher than in other areas due to lower access to health services, treatment-seeking behaviour of marginalized populations that typically inhabit border areas, difficulties in deploying prevention programmes to hard-to-reach communities, often in difficult terrain, and constant movement of people across porous national boundaries. Malaria elimination in border areas will be challenging and key to addressing the challenges is strengthening of surveillance activities for rapid identification of any importation or reintroduction of malaria. This could involve taking advantage of technological advances, such as spatial decision support systems, which can be deployed to assist programme managers to carry out preventive and reactive measures, and mobile phone technology, which can be used to capture the movement of people in the border areas and likely sources of malaria importation. Additionally, joint collaboration in the prevention and control of cross-border malaria by neighbouring countries, and reinforcement of early diagnosis and prompt treatment are ways forward in addressing the problem of cross-border malaria.

Clinical, geographical, and temporal risk factors associated with presentation and outcome of vivax malaria imported into the United Kingdom over 27 years: observational study

OBJECTIVE

To examine temporal and geographical trends, risk factors, and seasonality of imported vivax malaria in the United Kingdom to inform clinical advice and policy.

DESIGN

Observational study.

SETTING

National surveillance data from the UK Public Health England Malaria Reference Laboratory, data from the International Passenger Survey, and international climactic data.

PARTICIPANTS

All confirmed and notified cases of malaria in the UK (n=50,187) from 1987 to 2013, focusing on 12,769 cases of vivax malaria.

MAIN OUTCOME MEASURES

Mortality, sociodemographic details (age, UK region, country of birth and residence, and purpose of travel), destination, and latency (time between arrival in the UK and onset of symptoms).

RESULTS

Of the malaria cases notified, 25.4% (n=12,769) were due to Plasmodium vivax, of which 78.6% were imported from India and Pakistan. Most affected patients (53.5%) had travelled to visit friends and relatives, and 11.1% occurred in tourists. Imported P vivax is concentrated in areas with large communities of south Asian heritage. Overall mortality was 7/12,725 (0.05%), but with no deaths in 9927 patients aged under 50 years. Restricting the analysis to those aged more than 50 years, mortality was 7/2798 (0.25%), increasing to 4/526 (0.76%) (adjusted odds ratio 32.0, 95% confidence interval 7.1 to 144.0, P<0.001) in those aged 70 years or older. Annual notifications decreased sharply over the period, while traveller numbers between the UK and South Asia increased. The risk of acquiring P vivax from South Asia was year round but was twice as high from June to September (40 per 100,000 trips) compared with the rest of the year. There was strong seasonality in the latency from arrival in the UK to presentation, significantly longer in those arriving in the UK from South Asia from October to March (median 143 days) versus those arriving from April to September (37 days, P<0.001).

CONCLUSIONS

Travellers visiting friends and family in India and Pakistan are most at risk of acquiring P vivax, and older patients (especially those >70 years) are most at risk of dying; these groups should be targeted for advice before travelling. The risk of acquiring vivax malaria is year round but higher during summer monsoons, masked by latency. The latency of time to clinical presentation of imported vivax malaria in the UK is highly seasonal; seasonal latency has implications for pretravel advice but also for the control of malaria in India and Pakistan. A reduced incidence of vivax malaria in travellers may mean further areas of South Asia can be considered not to need malaria chemoprophylaxis.

Epidemiological and clinical characteristics of imported malaria in the United Arab Emirates

BACKGROUND

The United Arab Emirates (UAE) was certified by the World Health Organization to be free of endemic malaria transmission in 2007. There continued to be, however, a substantial number of imported malaria cases.

METHODS

A retrospective laboratory and chart review was performed to describe the epidemiological, clinical, and laboratory characteristics of imported malaria in Dubai, UAE. Laboratory records were reviewed at the largest public hospital in Dubai to identify cases of peripheral blood smear-positive malaria from January 1, 2008 to December 31, 2010. Predefined demographic, clinical, and laboratory information was extracted from the electronic medical record system.

RESULTS

A total of 629 cases of malaria were identified including 493, 122, and 14 cases of Plasmodium vivax, Plasmodium falciparum, and mixed P. vivax/P. falciparum infections, respectively. Of these, 567 (90.1%) cases were either from India or Pakistan and 7% from sub-Saharan Africa. There were no cases among the local Emirati population. There were 162 hospitalizations, including 8 requiring intensive care support and 1 death. More than 10% of P. vivax infections required hospitalization. The interval between arrival in the UAE and diagnosis was 3 months or longer for 25% of P. vivax cases.

CONCLUSIONS

Imported malaria remains an important cause of morbidity in the UAE. Clinicians need to be aware that P. vivax is not benign and can cause severe disease and that malaria cases may present to health facilities several months after arrival from malaria-endemic regions.

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.

Factors affecting the use of anti-malaria preventive measures among Taiwan immigrants returning to malaria-endemic regions

The aim of this study was to investigate the predictors of anti-malaria preventive measures (AMPMs) among Taiwan immigrants returning to their country of origin using the Health Belief Model (HBM). Between March and May 2011, all permanent immigrants originating from malaria-endemic countries, attended by either the Taipei or Tainan Immigrant Service Center, Taiwan, and who reported a history of returning to their country of origin within the preceding year during the malarious season in their country of origin were enrolled in the study. Complete information was collected from 316 immigrants, with a response rate of 87% (316/364). The mean age of the subjects was 38.1 years (SD = 9.9). The majority (70%) of participants did not receive travel information through a pre-travel consultation; more than 40% reported that they did not use measures to prevent insect bites. Multiple regression analyses revealed that Chinese proficiency, travel consultation before travel, lower perceived susceptibility to malaria, higher perceived severity of malaria infection, higher perceived benefit for taking measures, and higher self-efficacy for taking measures significantly predicted the use of AMPMs during the return to their country of origin (R(2) = 0.20; F = 50.42; P < 0.001). A high proportion of immigrants were not using appropriate AMPMs when they returned to their country. Educational approaches should be targeted toward immigrants who return to visit their country of origin.

Imported malaria in pregnancy in Madrid

BACKGROUND

Malaria in pregnancy is associated with maternal and foetal morbidity and mortality in endemic areas, but information on imported cases to non-endemic areas is scarce.The aim of this study was to describe the clinical and epidemiological characteristics of malaria in pregnancy in two general hospitals in Madrid, Spain.

METHODS

Retrospective descriptive study of laboratory-confirmed malaria in pregnant women at the Fuenlabrada University Hospital and the Príncipe de Asturias University Hospital, in Madrid, over a six- and 11-year period, respectively. Relevant epidemiological, clinical and laboratory data was obtained from medical records.

RESULTS

There were 19 pregnant women among 346 malaria cases (5.4%). The average age was 27 years. The gestational age (trimester) was: 53% 3rd, 31% 1st, 16% 2nd. All but one were multigravidae. Three were HIV positive. All were sub-Saharan immigrants: two were recently arrived immigrants and seventeen (89%) had visited friends and relatives. None had taken prophylaxis nor seeked pre-travel advice.

PRESENTATION

16 symptomatic patients (fever in fourteen, asthenia in two), three asymptomatic. Median delay in diagnosis: 7.5 days. Laboratory tests: anaemia (cut off Hb level 11 g/dl) 78.9% (mild 31.6%, moderate 31.6%, severe 15.8%) thrombocytopaenia 73.7%, hypoglycaemia 10.5%. All cases were due to Plasmodium falciparum, one case of hyperparasitaemia. Quinine + clindamycin prescribed in 84%.

OUTCOMES

no severe maternal complications or deaths, two abortions, fifteen term pregnancies, no low-birth-weight newborns, two patients were lost to follow-up.

CONCLUSIONS

Though cases of malaria in pregnancy are uncommon, a most at risk group is clearly defined: young sub-Saharan mothers visiting friends and relatives without pre-travel counselling and recently-arrived immigrants. The most common adverse maternal and foetal effects were anaemia and stillbirth. Given that presentation can be asymptomatic, malaria should always be considered in patients with unexplained anaemia arriving from endemic areas. These findings could help Maternal Health programme planners and implementers to target preventive interventions in the immigrant population and should create awareness among clinicians.

[Malaria among immigrants, experience of a Parisian hospital (2006-2010)]

In recent days immigrants represent the main risk group for imported malaria in northern countries. Most of them are migrants returning to their country of origin to visit friends and relatives (VFR). We retrospectively examined the main clinical, biological, and therapeutic data of all malaria cases in immigrants from 2006 to 2010 in Tenon hospital, Paris. The hospital is situated in a Paris district with an important African community. During the study period 239 imported malaria cases were observed in adults of which 199 were immigrants, 186 VFR, and 13 recently arrived. Most cases were from sub-Saharan Africa and Comoro islands. Chimioprophylaxis was not taken in 81.2% of VFR. It was inadequate in 43.7% and not taken correctly in 84.4%. Plasmodium falciparum was the most frequent species identified: 190/199 (95.5%). Severe P. falciparum malaria was observed in 25 cases (13.2%); two of them were recently arrived. One patient, African VFR, died. In this series two high-risk groups were represented: HIV-infected patients and pregnant women. Six of the HIV patients had severe malaria and all pregnant women had anemia. Our results are similar to those observed recently in other European countries. Mean age of VFR is increasing and the risk for severe P. falciparum malaria became identical to the one observed in non-immune travelers. Protection measures remain still insufficient in this population of travelers.

Imported malaria in Scotland--an overview of surveillance, reporting and trends

BACKGROUND

Imported malaria cases continue to occur and are often underreported. This study assessed reporting of malaria cases and their characteristics in Scotland.

METHODS

Cases were identified at the study sites of Aberdeen, Edinburgh, Glasgow and Inverness. The number of cases identified in the period 2003-2008 was compared to surveillance databases from Health Protection Scotland (HPS) and the Malaria Reference Laboratory (MRL). Case characteristics were recorded and analysed.

RESULTS

Of 252 cases of malaria diagnosed and treated, an estimated 235 (93.3%) were reported to the MRL. Between 2006 and 2008, 114 of 126 cases (90.5%) were reported to HPS. Plasmodium falciparum caused 173 cases (68.7%). Business and professional travel accounted for 35.3% of cases (higher in Aberdeen), followed by visiting friends and relatives (33.1%) and holiday makers (25.5%). The majority of infections were imported from West Africa and 65.7% of patients for whom data on prophylaxis was available had taken no or inappropriate prophylaxis.

CONCLUSIONS

Reporting of malaria in Scotland can be improved. There is a continued need to optimise preventive measures and adherence to chemoprophylaxis amongst business travellers, those visiting friends and relatives, and holiday makers in endemic countries in order to reduce imported malaria cases.

Eritrean and Sudanese migrants presenting with malaria in Israel

In Israel, a malaria-free country, we have noticed lately an increase of hospital admissions with malaria, parallel to the rise in the number of Eritrean and Sudanese migrants. Eritrea and Sudan are malaria-endemic countries; Plasmodium falciparum accounts for 85-90% and Plasmodium vivax accounts for 10-15% of malaria species in these areas. We aimed to describe the features of malaria in this migrant population by conducting a retrospective descriptive study of Eritrean and Sudanese migrants admitted with malaria during 1/2009-4/2010. Patient files were reviewed for demographics, clinical data, laboratory tests, treatment and outcome. 101 patients (mean age 24.9 (SD 5.6) years; 86.1% males) with malaria were identified. 87.1% were infected with P. vivax, 6% with P. falciparum, and 6.9% had both. All presented with pyrexia. None had respiratory or cerebral complications. Mean length of hospitalization was 2.49 (SD 1.5) days. No treatment failures or complications were observed. We conclude that in countries with waves of migrants from malaria-endemic areas, onset of fever should raise suspicion of malaria. Contrary to the known dominance of P. falciparum among malaria species in Eritrea and Sudan, the vast majority of migrants presented with P. vivax. The region of P. vivax acquisition remains unclear.

Clinical practice: the diagnosis of imported malaria in children

The present paper reviews the diagnosis of imported malaria in children. Malaria is caused by a parasite called Plasmodium and occurs in over 100 countries worldwide. Children account for 10-15% of all patients with imported malaria and are at risk to develop severe and life-threatening complications especially when infected with Plasmodium falciparum. Case-fatality ratios vary between 0.2% and 0.4%. Children visiting friends and relatives in malaria endemic areas and immigrants and refugees account for the vast majority of cases. Symptoms are non-specific and delayed infections (more than 3 months after return from an endemic country) may occur. Microscopic analysis of the thick blood film is the cornerstone of laboratory diagnosis. For pragmatic reasons, EDTA-anticoagulated blood is accepted, provided that slides are prepared within 1 h after collection. Information about the Plasmodium species (in particular P. falciparum versus the non-falciparum species) and the parasite density is essential for patient management. Molecular methods in reference settings are an adjunct for species differentiation. Signals generated by automated hematology analyzers may trigger the diagnosis of malaria in non-suspected cases. Malaria rapid diagnostic tests are reliable in the diagnosis of P. falciparum but not for the detection of the non-falciparum species. They do not provide information about parasite density and should be used as an adjunct (and not a substitute) to microscopy. In case of persistent suspicion and negative microscopy results, repeat testing every 8-12 h for at least three consecutive samplings is recommended. A high index of suspicion and a close interaction with the laboratory may assure timely diagnosis of imported malaria.

The position of mefloquine as a 21st century malaria chemoprophylaxis

BACKGROUND

Malaria chemoprophylaxis prevents the occurrence of the symptoms of malaria. Travellers to high-risk Plasmodium falciparum endemic areas need an effective chemoprophylaxis.

METHODS

A literature search to update the status of mefloquine as a malaria chemoprophylaxis.

RESULTS

Except for clearly defined regions with multi-drug resistance, mefloquine is effective against the blood stages of all human malaria species, including the recently recognized fifth species, Plasmodium knowlesi. New data were found in the literature on the tolerability of mefloquine and the use of this medication by groups at high risk of malaria.

DISCUSSION

Use of mefloquine for pregnant women in the second and third trimester is sanctioned by the WHO and some authorities (CDC) allow the use of mefloquine even in the first trimester. Inadvertent pregnancy while using mefloquine is not considered grounds for pregnancy termination. Mefloquine chemoprophylaxis is allowed during breast-feeding. Studies show that mefloquine is a good option for other high-risk groups, such as long-term travellers, VFR travellers and families with small children. Despite a negative media perception, large pharmaco-epidemiological studies have shown that serious adverse events are rare. A recent US evaluation of serious events (hospitalization data) found no association between mefloquine prescriptions and serious adverse events across a wide range of outcomes including mental disorders and diseases of the nervous system. As part of an in-depth analysis of mefloquine tolerability, a potential trend for increased propensity for neuropsychiatric adverse events in women was identified in a number of published clinical studies. This trend is corroborated by several cohort studies that identified female sex and low body weight as risk factors.

CONCLUSION

The choice of anti-malarial drug should be an evidence-based decision that considers the profile of the individual traveller and the risk of malaria. Mefloquine is an important, first-line anti-malarial drug but it is crucial for prescribers to screen medical histories and inform mefloquine users of potential adverse events. Careful prescribing and observance of contraindications are essential. For some indications, there is currently no replacement for mefloquine available or in the pipeline.

Declining incidence of imported malaria in the Netherlands, 2000-2007

BACKGROUND

To describe the epidemiology and trends of imported malaria in the Netherlands from 2000 through 2007.

METHODS

Based on national surveillance data regarding all reported infections of imported malaria, diagnosed 2000 through 2007, incidence and trends of imported malaria in the Netherlands were estimated. Travellers statistics were used to estimate incidence, and data on malaria chemoprophylaxis prescriptions were used to estimate the number of unprotected travellers.

RESULTS

Importation of malaria to the Netherlands is declining even as more travellers visit malaria-endemic countries. On average, 82% were acquired in sub-Saharan Africa, and 75% were caused by Plasmodium falciparum. The overall incidence in imported falciparum malaria fell from 21.5 to 6.6/10,000 of unprotected travellers. The percentage of unprotected travellers rose from 47% to 52% of all travellers. The incidence of imported falciparum infections is greatest from Middle and West Africa, and decreased from 121.3 to 36.5/10,000 travellers. The import of malaria from this region by immigrants visiting friends and relatives (VFR) decreased from 138 infections in 2000, to 69 infections in 2007.

CONCLUSION

The annual number of imported malaria shows a continuing declining trend, even with an increasing number of travellers visiting malaria endemic countries. VFR import less malaria than previously, and contribute largely to the declining incidence seen. The decline is not readily explained by increased use of chemoprophylaxis and may reflect a reduced risk of infection due to decreasing local malaria transmission as observed in some malaria endemic areas. Nevertheless, the increasing number of unprotected travellers remains worrisome.

Imported malaria in children: a comparative study between recent immigrants and immigrant travelers (VFRs)

BACKGROUND

In Europe, imported malarial cases occur in returning travelers and immigrants mostly from African countries. There have been an increasing number of cases in the past years in Spain.

METHODS

An analysis of all cases of malaria who attended at the Hospital of Mostoles in the Southwest of Madrid from 1995 to 2007 was performed. Clinical, epidemiological, laboratory, and parasitological findings were analyzed and compared between immigrants coming from endemic countries (recent immigrants) and children who traveled to endemic areas to visit friends and relatives (VFRs).

RESULTS

Sixty cases of imported malaria were detected. Most of the cases (59 of 60) were acquired in sub-Saharan Africa. The most common species was Plasmodium falciparum (43 of 60). Microscopic examination was positive in 95%, and the polymerase chain reaction (PCR) for Plasmodium achieved additional diagnosis in seven cases. Fourteen cases were VFRs; none of them used appropriate malaria chemoprophylaxis. Fever and thrombocytopenia were significantly more common among VFRs. They also had significantly higher parasite density. Twelve cases were asymptomatic at the time of diagnosis; all of them were recent immigrants.

CONCLUSIONS

VFRs account for a significant number of childhood malarial cases. These patients had not taken malaria chemoprophylaxis and malarial cases were more severe. VFR children are a high-risk group, and pretravel advice should underline the risk for malaria. Recent immigrants can be asymptomatic and parasitemias are lower. Therefore, a high index of suspicion is necessary, and PCR for Plasmodium should be performed in case of negative thick smears.

Malaria and travellers visiting friends and relatives

Among all travel-acquired illnesses, malaria carries the greatest burden not only considering the number of imported cases but also the potential of a fatal outcome. The increased number of imported malaria cases in developed countries in the last decades has been attributed to the increasing number of travel to tropical destinations in combination with the enormous influx of immigrants. At present, immigrants visiting friends and relatives (VFRs) constitute the most significant group of travellers for malaria importation in developed countries, with sub-Saharan Africa destinations carrying the highest risk. VFRs typically demonstrate travel and behavioural patterns which render them at high risk for acquisition of this largely preventable infection. Pre-travel services are rarely sought by VFRs, whereas misconceptions that they possess life-long immunity against malaria make them less likely to receive or adhere to antimalarial chemoprophylaxis recommendations. There is an urgent need to increase awareness about malaria of this group of travellers.

Malaria imported into Réunion Island: is there a risk of re-emergence of the disease?

After a long period of endemicity until the 1950s, the World Health Organization considered autochthonous malaria 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. The objective of this study is to report sociodemographic characteristics of imported malaria patients and incidence rates from 2003-2008 using mandatory notification with the aim of identifying risk groups and destinations. During this period, 684 imported malaria cases were reported. Median age of patients was 34.4 years and 22.1% were children </= 15 years. Men represented 67.7% of cases and 59.1% of patients reported having taken chemoprophylaxis based on chloroquine alone. Incidence of malaria was considerably different by country destination. For Comoros, incidence was stable and high during the period accounting for 1481 cases per 100000 travels in 2008. The rate was lower for travels to Madagascar, South Africa and Mayotte and decreased over the period to 37, 19 and 3 per 100000 respectively, by 2008. To avoid re-emergence of malaria on the island and to protect themselves, travelers should reduce their risks of acquisition and importation of parasites by using adequate preventive measures. A special preventive program and social mobilisation should be a priority, essentially for the Comorian community in Réunion.

Drugs for preventing malaria in travellers

BACKGROUND

Malaria infects 10,000 to 30,000 international travellers each year. It can be prevented through anti-mosquito measures and drug prophylaxis. However, antimalaria drugs have adverse effects which are sometimes serious.

OBJECTIVES

To compare the effects of currently used antimalaria drugs when given as prophylaxis to non-immune adult and child travellers who are travelling to regions with Plasmodium falciparum resistance to chloroquine. Specifically, to assess the efficacy, safety, and tolerability of atovaquone-proguanil, doxycycline, and mefloquine compared to each other, and also when compared to chloroquine-proguanil and to primaquine.

SEARCH STRATEGY

In August 2009 we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2008, Issue 4), MEDLINE, EMBASE, LILACS, BIOSIS, mRCT, and reference lists. We handsearched conference proceedings and one specialist journal, and contacted researchers and drug companies. We searched PubMed for drug-related deaths.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of any antimalaria drug regimen currently used by non-immune international travellers.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed eligibility and risk of bias using a standardized data collection form. We resolved any disagreement through discussion. We combined dichotomous outcomes using risk ratio (RR) and continuous data using mean difference (MD), presenting both with 95% confidence intervals (CI).

MAIN RESULTS

Eight trials (4240 participants) met the inclusion criteria. Evidence on comparative efficacy from head-to-head comparisons was limited. Atovaquone-proguanil compared to doxycycline had similar adverse events reported. Compared to mefloquine, atovaquone-proguanil users had fewer reports of any adverse effect (RR 0.72, 95% CI 0.6 to 0.85), gastrointestinal adverse effects (RR 0.54, 95% CI 0.42 to 0.7), neuropsychiatric adverse events (RR 0.86, 95% CI 0.75 to 0.99), and neuropsychiatric adverse effects (RR 0.49, 95% CI 0.38 to 0.63), besides a better total mood disturbance score (MD -7.20, 95% CI -10.79 to -3.61). Similarly, doxycycline users had fewer reported neuropsychiatric events than mefloquine users (RR 0.84, 95% CI 0.73 to 0.96). We also examined these three regimens against chloroquine-proguanil; this latter regimen had more reports of any adverse effect (RR 0.84, 95% CI 0.73 to 0.96) and of gastrointestinal adverse effects (RR 0.71, 95% CI 0.6 to 0.85).

AUTHORS' CONCLUSIONS

Atovaquone-proguanil and doxycycline are the best tolerated regimens, and mefloquine is associated with adverse neuropsychiatric outcomes.

Imported malaria in immigrants to Italy: a changing pattern observed in north eastern Italy

BACKGROUND

Seventy percent of imported malaria cases in Italy occur in immigrants, generally with milder clinical presentation due to premunition acquired through repeated infections. Nevertheless, premunition could be progressively lost after a long period of nonexposure. We investigated the changing pattern of malaria in immigrants in two definite 5-year periods one decade apart.

METHODS

We retrospectively examined the main laboratory findings of all malaria cases observed in immigrants from 1990 to 1994 and from 2000 to 2004. We stratified patients by reason for traveling: subjects in Italy who traveled to visit friends and relatives (VFR) or new immigrants (NI).

RESULTS

Forty-eight cases of malaria in immigrants occurred from 1990 to 1994, while 161 were observed from 2000 to 2004. Patients admitted in the latter period had a significantly higher parasitemia (median 6,298 vs 3,360 trophozoites/microL, p= 0.028) and lower platelet count (median 96.5 vs 132 x 10(9)/L, p= 0.012) and hemoglobin (median 12.6 vs 13.4 g/dL, p= 0.049). While NI did not show any significant difference in the two study periods, in the VFR subgroup a higher parasitemia (median 8,845 vs 2,690 trophozoites/microL, p= 0.003) and lower platelet count (median 96 vs 131 x 10(9)/L, p= 0.034) were observed during the second period, during which three cases of severe malaria occurred in VFR. A longer stay in Italy was reported in VFR admitted during the second study period (median 8.3 vs 5.7 years).

CONCLUSIONS

We found a changing pattern of malaria presentation in immigrants over a decade. The most likely explanation is the longer average stay outside endemic countries and subsequent loss of premunition observed in the second cohort. Immigrants living in Italy for some time and traveling to VFR should no more be considered a low-risk group for severe malaria. Pretravel advice should be particularly targeted to this group.

Travellers returning to Sweden with falciparum malaria: Pre-travel advice, behaviour, chemoprophylaxis and diagnostic delay

We have investigated pre-travel advice, behaviour, chemoprophylaxis and diagnostic delay in travellers returning to Sweden with falciparum malaria. Questionnaires were distributed to patients having been notified with falciparum malaria from 1994 to 2001. Of 408 notified patients, 237 (58%) returned the questionnaires; 62% were males and 43% above the age of 45 y. Africa was the travel destination in 90% of the cases, and 27% had travelled to Kenya. 69% had spent more than 1 night in the countryside, and 6% had stayed in modern urban areas only. 40% took an adequate dose of chemoprophylaxis, although this proportion decreased from 55% to 12% during the study period. Nine per cent used both bed nets and mosquito repellents regularly. The median time from onset of symptoms to contact with health care professionals was 2 d, and from that contact to start of malaria treatment the median time was less than 24 h.

Imported malaria in children in industrialized countries, 1992-2002

Children account for a considerable proportion of cases imported to the United States and Europe.

Children account for an appreciable proportion of total imported malaria cases, yet few studies have quantified these cases, identified trends, or suggested evidence-based prevention strategies for this group of travelers. We therefore sought to identify numbers of cases and deaths, Plasmodium species, place of malaria acquisition, preventive measures used, and national origin of malaria in children. We analyzed retrospective data from Australia, Denmark, France, Germany, Italy, Japan, the Netherlands, Sweden, Switzerland, the United Kingdom, and the United States and data provided by the United Nations World Tourism Organization. During 1992–2002, >17,000 cases of imported malaria in children were reported in 11 countries where malaria is not endemic; most (>70%) had been acquired in Africa. Returning to country of origin to visit friends and relatives was a risk factor. Malaria prevention for children should be a responsibility of healthcare providers and should be subsidized for low-income travelers to high-risk areas.

Fever in returned travellers presenting in the United Kingdom: recommendations for investigation and initial management

International travel is increasing. Most physicians and general practitioners will encounter returned travellers with fever and the majority of travel-related infection is associated with travel to the tropics. In those returning from the tropics malaria must always be excluded, and HIV considered, from all settings. Common causes of non-malarial fever include from Africa rickettsial diseases, amoebic liver abscess and Katayama syndrome; from South and South East Asia, enteric fever and arboviral infection; from the Middle East, brucellosis and from the Horn of Africa visceral leishmaniasis. Other rare but important diseases from particular geographical areas include leptospirosis, trypanosomiasis and viral haemorrhagic fever. North and South America, Europe and Australia also have infections which are geographically concentrated. Empirical treatment may have to be started based on epidemiological probability of infection whilst waiting for results to return. The evidence base for much of the management of tropical infections is limited. These recommendations provide a pragmatic approach to the initial diagnosis and management of fever in returned travellers, based on evidence where it is available and on consensus of expert opinion where it is not. With early diagnosis and treatment the majority of patients with a potentially fatal infection related to travel will make a rapid and full recovery.

The risk of malaria in travelers to India

BACKGROUND

Several countries have reported a decline in malaria cases imported by travelers returning from India.

METHODS

We collected data on imported malaria for the period 1992 to 2005 from nine countries. Traveler statistics denominator data were obtained from the Indian Ministry of Tourism.

RESULTS

The malaria case numbers declined from 93 cases per 100,000 travelers in 1992 to 19 cases per 100,000 travelers in 2005. The proportion of Plasmodium falciparum decreased steadily throughout the years. The proportion of Plasmodium vivax accounts for more than 80% of all cases of malaria in travelers to India. Deaths due to malaria were rare; only the UK and the United States reported deaths, a total of 16, between 1992 and 2005. The high-risk areas for malaria in India can be clearly identified using endemic malaria data. High-risk states are Chhattisgarh, Orissa, Jharkhand, West Bengal, Goa (mainly P vivax), and the states east of Bangladesh.

CONCLUSIONS

The decreasing incidence of malaria in travelers to India and the high proportion of P vivax support the current change in guidelines in some European countries advocating the use of the standby emergency self-treatment strategy or bite precautions plus awareness of risk instead of chemoprophylaxis. Otherwise in high-risk states, chemoprophylaxis should still be considered particularly in high-transmission seasons.

Imported malaria and high risk groups: observational study using UK surveillance data 1987-2006

OBJECTIVE

To examine temporal, geographic, and sociodemographic trends in case reporting and case fatality of malaria in the United Kingdom.

SETTING

National malaria reference laboratory surveillance data in the UK.

DESIGN

Observational study using prospectively gathered surveillance data and data on destinations from the international passenger survey.

PARTICIPANTS

39,300 cases of proved malaria in the UK between 1987 and 2006.

MAIN OUTCOME MEASURES

Plasmodium species; sociodemographic details (including age, sex, and country of birth and residence); mortality; destination, duration, and purpose of international travel; and use of chemoprophylaxis.

RESULTS

Reported cases of imported malaria increased significantly over the 20 years of the study; an increasing proportion was attributable to Plasmodium falciparum (P falciparum/P vivax reporting ratio 1.3:1 in 1987-91 and 5.4:1 in 2002-6). P vivax reports declined from 3954 in 1987-91 to 1244 in 2002-6. Case fatality of reported P falciparum malaria did not change over this period (7.4 deaths per 1000 reported cases). Travellers visiting friends and relatives, usually in a country in Africa or Asia from which members of their family migrated, accounted for 13 215/20 488 (64.5%) of all malaria reported, and reports were geographically concentrated in areas where migrants from Africa and South Asia to the UK have settled. People travelling for this purpose were at significantly higher risk of malaria than other travellers and were less likely to report the use of any chemoprophylaxis (odds ratio of reported chemoprophylaxis use 0.23, 95% confidence interval 0.21 to 0.25).

CONCLUSIONS

Despite the availability of highly effective preventive measures, the preventable burden from falciparum malaria has steadily increased in the UK while vivax malaria has decreased. Provision of targeted and appropriately delivered preventive messages and services for travellers from migrant families visiting friends and relatives should be a priority.

A retrospective study of 230 consecutive patients hospitalized for presumed travel-related illness (2000-2006)

A good knowledge of morbidity profiles among ill-returned travelers is necessary in order to guide their management. We reviewed the medical charts of 230 patients hospitalized in one infectious diseases department in France for presumed travel-related illnesses. The male-to-female ratio was 1.6 and the median age was 33 years (interquartile range [IQR], 25–50). Most patients (70.9%) were returning from sub-Saharan Africa. The median duration of travel was 28 days (IQR, 15–60) and the median time from return of travel to hospitalization was 13 days (IQR, 7–21). Malaria was the most frequent diagnosis (49.1%), which was especially encountered in patients returning from sub-Saharan Africa (95.6%), without adequate chemoprophylaxis (78.2%). Imported diseases at risk of secondary transmission were also diagnosed, including pulmonary tuberculosis (n = 8), viral hepatitis (n = 8), typhoid fever (n = 6), human immunodeficiency virus (HIV) (six new diagnosis), non-typhoid salmonellosis (n = 5), severe acute respiratory syndrome, and Crimean-Congo hemorrhagic fever. This study underlines the need to maintain tropical expertise for infectious diseases physicians, even in Europe.

Determinants of malaria prophylaxis among German travelers to Kenya, Senegal, and Thailand

BACKGROUND

Malaria chemoprophylaxis is a mainstay of malaria prevention in travelers. Adequate pretravel advice forms the basis for efficient malaria prophylaxis. This study assessed the determinants for seeking pretravel advice and evaluated the quality of advice from each source and its influence on the patterns and outcome of malaria prophylaxis intake.

METHODS

In March and April 2004, a self-administered questionnaire was distributed by cabin crews to passengers flying back to Germany from three popular tourist destinations: Kenya, Senegal, and Thailand. To evaluate the quality of advice and actual intake, figures were assessed against the official recommendations of the German Society of Travel Medicine and International Health (DTG).

RESULTS

A total of 1,001 passengers were included in the study (Kenya, 492; Senegal, 131; and Thailand, 378), of which 81% had sought any kind of pretravel health advice. Travelers' age and time of pretravel consultation were associated with the source of information consulted. Seventy-five percent of travelers from Senegal and Kenya received DTG compliant advice compared to only 17% of travelers from areas with low malaria risk in Thailand. Travelers returning from Kenya and Senegal had used correct chemoprophylaxis in only 65 and 47% of trips, respectively. In multivariate analysis, the factors determining correct intake among Senegal and Kenya travelers were receiving pretravel advice (from nonmedical professionals: OR 4.4, 95% CI 1.9-10.0 and from medical professionals: OR 15.4, 95% CI 7.3-32.4), a correct risk perception (OR 2.9, 95% CI 1.9-4.5), 2 to 3 weeks of travel abroad (vs a duration >3 wk: OR 2.2, 95% CI 1.3-3.8), and travel to Kenya (OR 1.9, 95% CI 1.1-3.1).

CONCLUSIONS

Malaria prevention among a large proportion of German travelers to tropical destinations is inadequate. Public health efforts should be made to raise awareness among travelers, travel agencies, and medical institutions in Germany.

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

Plasmodium falciparum malaria is a serious health hazard for travelers to malaria-endemic areas and is often diagnosed on return to the country of residence. We conducted a retrospective study of imported falciparum malaria among travelers returning to France from malaria-endemic areas from 1996 through 2003. Epidemiologic, clinical, and parasitologic data were collected by a network of 120 laboratories. Factors associated with fatal malaria were identified by logistic regression analysis. During the study period, 21,888 falciparum malaria cases were reported. There were 96 deaths, for a case-fatality rate of 4.4 per 1,000 cases of falciparum malaria. In multivariate analysis, risk factors independently associated with death from imported malaria were older age, European origin, travel to East Africa, and absence of chemoprophylaxis. Fatal imported malaria remains rare and preventable. Pretravel advice and malaria management should take into account these risk factors, particularly for senior travelers.

Paludismo importado en un hospital general de Madrid

INTRODUCTION

To study the clinical and epidemiological characteristics of malaria and the diagnosis of this condition in a general hospital that does not have a specialized tropical medicine unit.

METHODS

Retrospective study of all malaria cases diagnosed by thick film and/or PCR-positive status for any Plasmodium spp. from 1999 to 2003 in Hospital Príncipe de Asturias in Alcalá de Henares (Madrid, Spain).

RESULTS

Over the period studied, 89 cases of malaria were diagnosed. Most patients were African immigrants who had recently left their countries of origin (52%), or immigrants residing in Spain who had traveled to Africa for a short visit (35%) and did not take prophylaxis. The distribution of cases by species was Plasmodium falciparum 89%, P. ovale 7% and P. malariae 4%. Clinical data were non-specific and the percentage of severe complications was low (6.7%). A second-generation test for rapid detection of P. falciparum antigen (PfHRP2) was studied in a group of 46 patients with suspected malaria; the results obtained were similar to thick film as compared to PCR for diagnosing P. falciparum infection.

CONCLUSIONS

Access to information on prevention and chemoprophylaxis should be available to all travelers, particularly immigrants visiting their countries of origin. Most semi-immune patients with uncomplicated malaria can be treated on an outpatient basis. PfHRP2 antigen detection, a fast, reliable method for diagnosing malaria due to P. falciparum, can be used in addition to the thick film method in our setting.

Imported infectious disease and purpose of travel, Switzerland

We evaluated the epidemiologic factors of patients seeking treatment for travel-associated illness from January 2004 through May 2005 at the University Hospital of Zurich. When comparing persons whose purpose of travel was visiting friends and relatives (VFR travelers; n = 121) with tourists and other travelers (n = 217), VFR travelers showed a distinct infectious disease and risk spectrum. VFR travelers were more likely to receive a diagnosis of malaria (adjusted odds ratio [OR] = 2.9, 95% confidence interval [CI] 1.2-7.3) or viral hepatitis (OR = 3.1, 95% CI 1.1-9) compared with other travelers but were less likely to seek pretravel advice (20% vs. 67%, p = 0.0001). However, proportionate rates of acute diarrhea were lower in VFR (173 vs. 364 per 1,000 ill returnees). Travel to sub-Saharan Africa contributed most to malaria in VFR travelers. In countries with large migrant populations, improved public health strategies are needed to reach VFR travelers.

Illness in Travelers Visiting Friends and Relatives: A Review of the GeoSentinel Surveillance Network

Travelers returning to their country of origin to visit friends and relatives (VFRs) have increased risk of travel-related health problems. We examined GeoSentinel data to compare travel characteristics and illnesses acquired by 3 groups of travelers to low-income countries: VFRs who had originally been immigrants (immigrant VFRs), VFRs who had not originally been immigrants (traveler VFRs), and tourist travelers. Immigrant VFRs were predominantly male, had a higher mean age, and disproportionately required treatment as inpatients. Only 16% of immigrant VFRs sought pretravel medical advice. Proportionately more immigrant VFRs visited sub-Saharan Africa and traveled for >30 days, whereas tourist travelers more often traveled to Asia. Systemic febrile illnesses (including malaria), nondiarrheal intestinal parasitic infections, respiratory syndromes, tuberculosis, and sexually transmitted diseases were more commonly diagnosed among immigrant VFRs, whereas acute diarrhea was comparatively less frequent. Immigrant VFRs and traveler VFRs had different demographic characteristics and types of travel-related illnesses. A greater proportion of immigrant VFRs presented with serious, potentially preventable travel-related illnesses than did tourist travelers.

Fever in travelers returning from tropical areas: prospective observational study of 613 cases hospitalised in Marseilles, France, 1999-2003

Background

Febrile travelers may pose a diagnostic challenge for Western physicians who are frequently involved in the assessment of these patients but unfamiliar with tropical diseases. Evaluation of this situation requires an understanding of the common etiologies, which are associated with the demographics of travelers and the destinations.

Methods

We conducted a 5-year prospective observational study on the etiologies of fever in travelers returning from the tropics admitted to the infectious and tropical diseases unit of a university teaching hospital in Marseilles, France.

Results

A total of 613 patients were enrolled, including 364 migrants (59.4%), 126 travelers (20.6%), 37 visitors (6%), 24 expatriates (3.9%), and 62 patients (10.1%) who could not be classified. Malaria was the most common diagnosis (75.2%), with most cases (62%) acquired by migrants from the Comoros archipelago and who had traveled to these islands to visit friends and relatives. Agents of food-borne and water-borne infections (3.9%) and respiratory tract infections (3.4%) were also frequently identified as the cause of fever. Other infections included emerging diseases such as gnathostomiasis, hepatitis E infection and rickettsial diseases, as well as common infections or exotic diseases.

Conclusions

Although we have identified here various causes of imported fever, 8.2% of the fevers remained unexplained. An improved approach to diagnosis may allow for the discovery of new diseases in travelers in the future.

Paediatric malaria: What do paediatricians need to know?

Although malaria is principally a disease of the tropical and subtropical regions of the world, it is an important disease to be familiar with for both local and global reasons. It remains to be one of the most important infectious diseases of the world, particularly in sub-Saharan Africa, killing more than one million people - mostly children - every year. In Canada, at least 350 to 1100 imported cases are reported annually, 25% of which are in the paediatric age group, as a result of both travel and migration. Because malaria is a potentially severe and sometimes fatal disease that is unfamiliar to many paediatricians in Canada, it is important that clinicians become familiar with its clinical presentation; understand when it should be suspected; and have an approach to prompt diagnosis, appropriate treatment and effective prevention methods.

Patterns of imported malaria at the academic medical center, Amsterdam, the Netherlands

BACKGROUND

In the Netherlands, cases of imported malaria peaked in the late 1990s to around 500 (60% Plasmodium falciparum) annually. About 30% to 40% of all cases and 57% to 69% of the falciparum cases presented in the Academic Medical Center, Amsterdam. In 1991 to 1994, a shift in population groups to more semi-immune patients, mostly settled immigrants visiting friends and relatives (VFRs), was noticed, when compared to 1979 to 1988. This study shows the ongoing trend in 2000 to 2002.

METHODS

All the patients diagnosed with malaria in the Academic Medical Center, Amsterdam, during 2000 to 2002 were analyzed. Nonimmune and semi-immune patients were analyzed separately.

RESULTS

A total of 302 patients were diagnosed with malaria: 207 (69%) were male; mean age was 34.0 years (range 1-74 years). Of the 302 patients, 105 (35%) were nonimmune travelers and 197 (65%) were considered semi-immune. In 248 (82%) patients, P falciparum was found. In 28 (9.3%), 15 (5.0%), and 6 (2.0%) cases, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae were diagnosed, respectively. Of the 248 falciparum cases, 233 (94%) were infected in sub-Saharan Africa; 90% of them had a parasitemia and <2 and 4% had a parasitemia exceeding 5% (maximum 43.7%). The majority of the falciparum cases (96%) were diagnosed within 30 days after return. The number of nonimmune patients with falciparum malaria decreased sharply from 42 in 2000 to 31 in 2001 to 13 in 2002, accounting for the decrease in all malaria cases, from 118 in 2000 to 82 in 2002. Fifty-four percent of vivax infections were acquired in Southeast Asia and 46% in Latin America and sub-Saharan Africa; 71% of the patients presented after 30 days (delayed primary attacks). All the P ovale infections were acquired in sub-Saharan Africa (73% delayed primary attacks).

CONCLUSIONS

During 2000 to 2002, the total number of patients with falciparum malaria was steadily decreasing due to a decrease in nonimmune patients. The number of semi-immune patients, mostly VFRs and visitors, remained stable. The increasing use of more convenient chemoprophylactic drugs, like atovaquone/proguanil, appears to improve compliance in those who can afford the drug.

[Imported malaria at the Marseilles Hôpital-Nord, France: a prospective study on 352 cases between 2001 and 2003]

OBJECTIVE

The authors had for aim to study epidemiological, clinical, and parasitological characteristics, as well as regimen received, of imported malaria cases hospitalised at the North University Hospital, in Marseilles, France.

DESIGN

The patients presenting with imported malaria included in this study were hospitalised in the infectious and tropical diseases unit and in the pediatrics unit at the North University Hospital, from January 1, 2001 to December 31, 2003. Variables were prospectively collected and recorded.

RESULTS

352 patients including 240 adults and 112 children were included. Most of them (67% of the adults and 92% of the children) were contaminated during a trip to the Comoros Islands. Plasmodium falciparum was the most common species identified. 97.5% of adult and 98% of child patients back from Comoros did not take any chemoprophylaxis against malaria or took inadequate regimens. Halofantrin was the most commonly used drug for children to treat uncomplicated P. falciparum malaria. In adults, atovaquone-proguanil was used as a first line drug in the absence of vomiting, and a 3-day intravenous regimen of quinine-clindamycin in case of vomiting.

CONCLUSION

The specificity of imported malaria in Marseilles is the high proportion of Comorian patients who go back home periodically to visit friends and relatives. A better education of the Comorian population in Marseilles, regarding malaria risks and prophylaxis, needs to be implemented.