The geography of imported malaria to non-endemic countries: a meta-analysis of nationally reported statistics

Seasonal and interannual risks of dengue introduction from South-East Asia into China, 2005-2015

Due to worldwide increased human mobility, air-transportation data and mathematical models have been widely used to measure risks of global dispersal of pathogens. However, the seasonal and interannual risks of pathogens importation and onward transmission from endemic countries have rarely been quantified and validated. We constructed a modelling framework, integrating air travel, epidemiological, demographical, entomological and meteorological data, to measure the seasonal probability of dengue introduction from endemic countries. This framework has been applied retrospectively to elucidate spatiotemporal patterns and increasing seasonal risk of dengue importation from South-East Asia into China via air travel in multiple populations, Chinese travelers and local residents, over a decade of 2005-15. We found that the volume of airline travelers from South-East Asia into China has quadrupled from 2005 to 2015 with Chinese travelers increased rapidly. Following the growth of air traffic, the probability of dengue importation from South-East Asia into China has increased dramatically from 2005 to 2015. This study also revealed seasonal asymmetries of transmission routes: Sri Lanka and Maldives have emerged as origins; neglected cities at central and coastal China have been increasingly vulnerable to dengue importation and onward transmission. Compared to the monthly occurrence of dengue reported in China, our model performed robustly for importation and onward transmission risk estimates. The approach and evidence could facilitate to understand and mitigate the changing seasonal threat of arbovirus from endemic regions.

Management of severe imported malaria in adults

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

Health preparedness plan for dengue detection during the 2020 summer Olympic and Paralympic games in Tokyo

Background

Participants in mass gathering events are at risk of acquiring imported and locally endemic infectious diseases. The 2014 dengue outbreak in Tokyo gathered attention since it was the first time in 70 years for Japan to experience an autochthonous transmission. Preparation for emerging infectious threats is essential even in places where these outbreaks have been largely unknown. The aim of this study is to identify strategies for early detection and prevention of dengue infection during the 2020 summer Olympics and Paralympics in Tokyo.

Methodology/Principal findings

We modified and adapted the failure mode and effect analysis (FMEA) methodology, generally used in industrial manufacturing, to examine the current controls for dengue detection and assessment. Information on existing controls were obtained from publicly available resources. Our analysis revealed that the national infectious disease control system to detect dengue in Japan is robust. However, in the case of large assemblies of international visitors for special events when the spread of communicable and vector-borne diseases increases, there are three main gaps that could be reinforced. First, cyclical training or a certification program on tropical disease management is warranted for physicians, especially those working in non-infectious disease-designated hospitals or clinics. Second, multi-language communication methods need to be strengthened especially in the health and hospitality sector. Third, owners of accommodations should consider incorporating a formal tropical disease-training program for their staff members and have a contingency plan for infectious disease-suspected travelers.

Conclusions/Significance

Our findings may facilitate physicians and public health officials where new controls would be beneficial for the 2020 summer Olympics and Paralympics. The FMEA framework has the potential to be applied to other infectious diseases, not just dengue.

Dengue is a mosquito-borne disease that is most prevalent among the emerging arboviruses. Most patients recover from dengue without complications, but a small portion of cases may progress to severe dengue which carries a high mortality rate if left untreated. In 2014, a dengue outbreak unexpectedly occurred in Tokyo, which was the first time in 70 years for Japan to experience an autochthonous transmission. Thus, preparation for dengue and other emerging infectious threats is essential even in places where these outbreaks have been largely unknown. Tokyo will be hosting the Olympic and Paralympic games in 2020, and interventions are warranted to mitigate the risks. We modified and adapted the failure mode effect analysis (FMEA) methodology to test the vulnerability and resiliency of the current controls. Although the FMEA methodology is generally used in industrial manufacturing, it has the potential to be utilized for health preparedness for other infectious diseases as well. Our analysis identifies three strategies to reinforce early detection of dengue infection and prevent further transmission during the Olympic and Paralympic Games.

Malaria Surveillance - United States, 2015

PROBLEM/CONDITION

Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles species mosquito. The majority of malaria infections in the United States occur among persons who have traveled to regions with ongoing malaria transmission. However, malaria is occasionally acquired by persons who have not traveled out of the country through exposure to infected blood products, congenital transmission, laboratory exposure, or local mosquitoborne transmission. Malaria surveillance in the United States is conducted to provide information on its occurrence (e.g., temporal, geographic, and demographic), guide prevention and treatment recommendations for travelers and patients, and facilitate transmission control measures if locally acquired cases are identified.

PERIOD COVERED

This report summarizes confirmed malaria cases in persons with onset of illness in 2015 and summarizes trends in previous years.

DESCRIPTION OF SYSTEM

Malaria cases diagnosed by blood film microscopy, polymerase chain reaction, or rapid diagnostic tests are reported to local and state health departments by health care providers or laboratory staff members. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS), the National Notifiable Diseases Surveillance System (NNDSS), or direct CDC consultations. CDC reference laboratories provide diagnostic assistance and conduct antimalarial drug resistance marker testing on blood samples submitted by health care providers or local or state health departments. This report summarizes data from the integration of all NMSS and NNDSS cases, CDC reference laboratory reports, and CDC clinical consultations.

RESULTS

CDC received reports of 1,517 confirmed malaria cases, including one congenital case, with an onset of symptoms in 2015 among persons who received their diagnoses in the United States. Although the number of malaria cases diagnosed in the United States has been increasing since the mid-1970s, the number of cases decreased by 208 from 2014 to 2015. Among the regions of acquisition (Africa, West Africa, Asia, Central America, the Caribbean, South America, Oceania, and the Middle East), the only region with significantly fewer imported cases in 2015 compared with 2014 was West Africa (781 versus 969). Plasmodium falciparum, P. vivax, P. ovale, and P. malariae were identified in 67.4%, 11.7%, 4.1%, and 3.1% of cases, respectively. Less than 1% of patients were infected by two species. The infecting species was unreported or undetermined in 12.9% of cases. CDC provided diagnostic assistance for 13.1% of patients with confirmed cases and tested 15.0% of P. falciparum specimens for antimalarial resistance markers. Of the U.S. resident patients who reported purpose of travel, 68.4% were visiting friends or relatives. A lower proportion of U.S. residents with malaria reported taking any chemoprophylaxis in 2015 (26.5%) compared with 2014 (32.5%), and adherence was poor in this group. Among the U.S residents for whom information on chemoprophylaxis use and travel region were known, 95.3% of patients with malaria did not adhere to or did not take a CDC-recommended chemoprophylaxis regimen. Among women with malaria, 32 were pregnant, and none had adhered to chemoprophylaxis. A total of 23 malaria cases occurred among U.S. military personnel in 2015. Three cases of malaria were imported from the approximately 3,000 military personnel deployed to an Ebola-affected country; two of these were not P. falciparum species, and one species was unspecified. Among all reported cases in 2015, 17.1% were classified as severe illnesses and 11 persons died, compared with an average of 6.1 deaths per year during 2000-2014. In 2015, CDC received 153 P. falciparum-positive samples for surveillance of antimalarial resistance markers (although certain loci were untestable for some samples); genetic polymorphisms associated with resistance to pyrimethamine were identified in 132 (86.3%), to sulfadoxine in 112 (73.7%), to chloroquine in 48 (31.4%), to mefloquine in six (4.3%), and to artemisinin in one (<1%), and no sample had resistance to atovaquone. Completion of data elements on the malaria case report form decreased from 2014 to 2015 and remains low, with 24.2% of case report forms missing at least one key element (species, travel history, and resident status).

INTERPRETATION

The decrease in malaria cases from 2014 to 2015 is associated with a decrease in imported cases from West Africa. This finding might be related to altered or curtailed travel to Ebola-affected countries in in this region. Despite progress in reducing malaria worldwide, the disease remains endemic in many regions, and the use of appropriate prevention measures by travelers is still inadequate.

PUBLIC HEALTH ACTIONS

The best way to prevent malaria is to take chemoprophylaxis medication during travel to a country where malaria is endemic. As demonstrated by the U.S. military during the Ebola response, use of chemoprophylaxis and other protection measures is possible in stressful environments, and this can prevent malaria, especially P. falciparum, even in high transmission areas. Detailed recommendations for preventing malaria are available to the general public at the CDC website (https://www.cdc.gov/malaria/travelers/drugs.html). Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age and medical history, the likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Health care providers should consult the CDC Guidelines for Treatment of Malaria in the United States and contact the CDC's Malaria Hotline for case management advice when needed. Malaria treatment recommendations are available online (https://www.cdc.gov/malaria/diagnosis_treatment) and from the Malaria Hotline (770-488-7788 or toll-free at 855-856-4713). Persons submitting malaria case reports (care providers, laboratories, and state and local public health officials) should provide complete information because incomplete reporting compromises case investigations and efforts to prevent infections and examine trends in malaria cases. Compliance with recommended malaria prevention strategies is low among U.S. travelers visiting friends and relatives. Evidence-based prevention strategies that effectively target travelers who are visiting friends and relatives need to be developed and implemented to reduce the numbers of imported malaria cases in the United States. Molecular surveillance of antimalarial drug resistance markers (https://www.cdc.gov/malaria/features/ars.html) has enabled CDC to track, guide treatment, and manage drug resistance in malaria parasites both domestically and internationally. More samples are needed to improve the completeness of antimalarial drug resistance marker analysis; therefore, CDC requests that blood specimens be submitted for all cases diagnosed in the United States.

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

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

Risk factors for Burkitt lymphoma: a nested case-control study in the UK Clinical Practice Research Datalink

Burkitt lymphoma (BL) occurs as three subtypes: endemic BL, immunosuppression-related BL and sporadic BL. Descriptive studies of BL age-specific incidence patterns have suggested multimodal peaks near 10, 40 and 70 years of age, but the risk factors for BL at different ages are unknown. We investigated risk factors for BL in the United Kingdom among 156 BL cases and 608 matched BL-free controls identified in the Clinical Practice Research Datalink (CPRD) between 1992 and 2016. Associations with pre-diagnostic body mass index, cigarette smoking, alcohol consumption, hepatitis, Epstein-Barr virus (EBV), human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS), malaria, allergic and autoimmune conditions, and prednisone use were evaluated. Overall, we identified inverse associations between smoking and BL risk, and positive associations between prior EBV infection, HIV/AIDS and prescription or use of prednisone with BL risk. In age-group stratified analyses, BL was associated with malaria exposure (vs. no exposure, odds ratio [OR] 8·00, 95% confidence interval [CI] 1·46-43·7) among those aged 20-59 years old and with hepatitis infection (vs. no infection, OR 3·41, 95% CI 1·01-11·5) among those aged 60+ years old. The effects of EBV, malaria, HIV/AIDS, prednisone and hepatitis on BL remained significant in mutually-adjusted age-group-specific analyses. No risk factors were associated with childhood BL. We report novel associations for BL in non-endemic settings.

Malaria in Children

Malaria remains widespread throughout the planet and increasing global travel continues to lead to imported cases of malaria in travelers, including children. This article provides an overview of pediatric malaria, including its epidemiology, clinical features, diagnosis, treatment, and prevention in travelers.

Converging Human and Malaria Vector Diagnostics with Data Management towards an Integrated Holistic One Health Approach

Monitoring malaria prevalence in humans, as well as vector populations, for the presence of Plasmodium, is an integral component of effective malaria control, and eventually, elimination. In the field of human diagnostics, a major challenge is the ability to define, precisely, the causative agent of fever, thereby differentiating among several candidate (also non-malaria) febrile diseases. This requires genetic-based pathogen identification and multiplexed analysis, which, in combination, are hardly provided by the current gold standard diagnostic tools. In the field of vectors, an essential component of control programs is the detection of Plasmodium species within its mosquito vectors, particularly in the salivary glands, where the infective sporozoites reside. In addition, the identification of species composition and insecticide resistance alleles within vector populations is a primary task in routine monitoring activities, aiming to support control efforts. In this context, the use of converging diagnostics is highly desirable for providing comprehensive information, including differential fever diagnosis in humans, and mosquito species composition, infection status, and resistance to insecticides of vectors. Nevertheless, the two fields of human diagnostics and vector control are rarely combined, both at the diagnostic and at the data management end, resulting in fragmented data and mis- or non-communication between various stakeholders. To this direction, molecular technologies, their integration in automated platforms, and the co-assessment of data from multiple diagnostic sources through information and communication technologies are possible pathways towards a unified human vector approach.

Imported malaria in northern Italy: epidemiology and clinical features observed over 18 years in the Teaching Hospital of Brescia

BACKGROUND

Even though malaria incidence is decreasing worldwide, travel-related cases reported in Europe have remained stable in recent years. In Italy, incidence had increased in the 1990s, reaching a peak in 1999; a slow decline was then reported over the subsequent decade. To our knowledge, few published data are available on imported malaria in Italy since 2010. In this article we aimed to analyse trends in imported malaria in the teaching hospital of Brescia, northern Italy, over the last 18 years.

METHODS

All malaria cases diagnosed from 1999 to 2016 in Spedali Civili Hospital, Brescia, were retrospectively identified. Demographic, clinical and travel-related data were described.

RESULTS

A total of 1200 cases of imported malaria were diagnosed in Brescia during the study period. Among them, 225 were children. A trend of increasing paediatric cases was identified over the study period, while cases in adults were stable. Most cases were diagnosed between August and October. Patients were most likely exposed in sub-Saharan Africa (87.2%). The main reported travel reason was travelling to visit friends and relatives (66.0%). A significantly higher risk of severe malaria was observed in non-immune patients and children visiting friend and relatives (P < 0.001 and P = 0.006, respectively).

CONCLUSIONS

Our study reveals a relatively stable incidence in imported malaria cases with a peak during the summertime. A large and increasing paediatric burden of disease was identified. Imported malaria requires attention since in Italy a potential reappearance of autochthonous Plasmodium vivax malaria transmission cannot be excluded. Preventive action and physician awareness should be especially directed to children visiting friends and relatives in endemic countries and to non-immune patients since they both represent high-risk groups for severe malaria.

Tafenoquine for travelers' malaria: evidence, rationale and recommendations

Background

Endemic malaria occurring across much of the globe threatens millions of exposed travelers. While unknown numbers of them suffer acute attacks while traveling, each year thousands return from travel and become stricken in the weeks and months following exposure. This represents perhaps the most serious, prevalent and complex problem faced by providers of travel medicine services. Since before World War II, travel medicine practice has relied on synthetic suppressive blood schizontocidal drugs to prevent malaria during exposure, and has applied primaquine for presumptive anti-relapse therapy (post-travel or post-diagnosis of Plasmodium vivax) since 1952. In 2018, the US Food and Drug Administration approved the uses of a new hepatic schizontocidal and hypnozoitocidal 8-aminoquinoline called tafenoquine for the respective prevention of all malarias and for the treatment of those that relapse (P. vivax and Plasmodium ovale).

Methods

The evidence and rationale for tafenoquine for the prevention and treatment of malaria was gathered by means of a standard search of the medical literature along with the package inserts for the tafenoquine products Arakoda™ and Krintafel™ for the prevention of all malarias and the treatment of relapsing malarias, respectively.

Results

The development of tafenoquine-an endeavor of 40 years-at last brings two powerful advantages to travel medicine practice against the malaria threat: (i) a weekly regimen of causal prophylaxis; and (ii) a single-dose radical cure for patients infected by vivax or ovale malarias.

Conclusions

Although broad clinical experience remains to be gathered, tafenoquine appears to promise more practical and effective prevention and treatment of malaria. Tafenoquine thus applied includes important biological and clinical complexities explained in this review, with particular regard to the problem of hemolytic toxicity in G6PD-deficient patients.

Nationwide genetic surveillance of Plasmodium vivax in Papua New Guinea reveals heterogeneous transmission dynamics and routes of migration amongst subdivided populations

The Asia Pacific Leaders in Malaria Alliance (APLMA) have committed to eliminate malaria from the region by 2030. Papua New Guinea (PNG) has the highest malaria burden in the Asia-Pacific region but with the intensification of control efforts since 2005, transmission has been dramatically reduced and Plasmodium vivax is now the dominant malaria infection in some parts of the country. To gain a better understanding of the transmission dynamics and migration patterns of P. vivax in PNG, here we investigate population structure in eight geographically and ecologically distinct regions of the country. A total of 219 P. vivax isolates (16-30 per population) were successfully haplotyped using 10 microsatellite markers. A wide range of genetic diversity (H_e=0.37-0.87, R_s=3.60-7.58) and significant multilocus linkage disequilibrium (LD) was observed in six of the eight populations (I_A^S=0.08-0.15 p-value<0.05) reflecting a spectrum of transmission intensities across the country. Genetic differentiation between regions was evident (Jost's D=0.07-0.72), with increasing divergence of populations with geographic distance. Overall, P. vivax isolates clustered into three major genetic populations subdividing the Mainland lowland and coastal regions, the Islands and the Highlands. P. vivax gene flow follows major human migration routes, and there was higher gene flow amongst Mainland parasite populations than among Island populations. The Central Province (samples collected in villages close to the capital city, Port Moresby), acts as a sink for imported infections from the three major endemic areas. These insights into P. vivax transmission dynamics and population networks will inform targeted strategies to contain malaria infections and to prevent the spread of drug resistance in PNG.

Molecular surveillance of chloroquine drug resistance markers (Pfcrt and Pfmdr1) among imported Plasmodium falciparum malaria in Qatar

Imported malaria has been a great challenge for public health in Qatar due to influx of large number of migrant workers. Antimalarial drug resistance has emerged as one of the greatest challenges facing malaria control today. Monitoring parasite haplotypes that predict susceptibility to major antimalarial can guide treatment policies. This study aimed to determine molecular drug resistance pattern in imported malaria cases in Qatar. Blood samples from the uncomplicated P. falciparum malaria patients were collected at Hamad General Hospital, HMC, Doha, Qatar. The samples were further confirmed by nested-polymerase chain reaction (PCR) for P. falciparum. Molecular markers of chloroquine (Pfcrt and Pfmdr1) were analyzed by using nested PCR- RFLP method to determine the key point mutations associated with chloroquine (CQ) drug resistance. A total 118 blood samples were positive for P. falciparum. Overall, by RFLP, 72% harboured wild type allele (N86) of Pfmdr1 gene. The prevalence of Pfcrt mutant (T76), WT (K76) and mixed alleles (K76T) was 63.6% (n = 75), 22.9% (n = 27) and 13.5% (n = 16), respectively. Mean parasitaemia level was higher among the wild type alleles of Pfcrt gene as compared to the mixed/mutant alleles whereas mixed alleles of Pfmdr1 gene having high parasitaemia. Molecular surveillance strategy based on imported malaria cases can be used to detect and track CQ drug-resistant malaria. The data presented here might be helpful for enrichment of molecular surveillance of antimalarial resistance and will be useful for developing and updating antimalarial guidance for non-immune imported cases in Qatar.

One-sixth of inpatients in a Danish infectious disease ward have imported diseases: A cross-sectional analysis

BACKGROUND

The aim of the study was to describe travel demographics and disease patterns of patients hospitalized with travel-related diseases, and assess risk factors to improve pre-travel information and post-travel diagnostics and treatment.

METHODS

The study included all patients hospitalized with travel-related diseases in 2015 at a Danish infectious diseases ward. Patient data was extracted from the in-patient hospital registry. was analyzed regarding diagnoses, destination, purpose of travel and pre-travel information.

RESULTS

240 patients were hospitalized with a total of 289 travel-related diseases, accounting for 16.6% (240/1450) of all admissions. Febrile illnesses were the most common (39.5%, 114/289) followed by respiratory (19.7%, 57/289) and gastrointestinal diagnoses (19.0%, 55/289). Most of the diseases were acquired in Sub-Saharan Africa (35.6%, 103/289) followed by South East Asia (27.0%, 78/289), and 60.0% (144/240) of the patients were tourists. One-third (36.3%, 81/223) of the non-migrants had received pre-travel information. The lowest rate was seen in people visiting friends and relatives (18.2%, 6/32).

CONCLUSION

Travel-related diseases are common among patients admitted to this Danish infectious disease ward. Malaria is the most common disease among both travelers and immigrants. In approximately one third of all the patients in our study etiology was unknown.

Diagnostic performance of the loop-mediated isothermal amplification (LAMP) based illumigene® malaria assay in a non-endemic region

Background

Light microscopy and antigen-based rapid diagnostic tests are the primary diagnostic tools for detecting malaria, although being labour-intensive and frequently challenged by lack of personnel’s experience and low levels of parasite density. The latter being especially important in non-endemic settings. Novel molecular techniques aim to overcome this drawback. The objective of this study was to assess the diagnostic performance of the illumigene malaria assay^® (Meridian Bioscience) compared to microscopy, RDT and real-time PCR. This loop-mediated isothermal amplification (LAMP) assay is a qualitative in vitro diagnostic test for the direct detection of Plasmodium spp. DNA in human venous whole blood samples.

Methods

The illumigene assay was assessed on a retrospective panel of stored blood samples (n = 103) from returned travellers and external quality control samples (n = 12). Additionally the assay was prospectively assessed on 30 fresh routine samples with a request for malaria diagnosis. The illumigene assay was compared to microscopy, RDT and Plasmodium species specific real-time PCR.

Results

In the retrospective evaluation, the illumigene assay showed 100% agreement with the real-time PCR, RDT and microscopy yielding a sensitivity and specificity of 100% (95% CI 95.1–100% and 89.7–100%, respectively). Seven samples from patients recently treated for Plasmodium falciparum infection that were RDT positive and microscopy negative yielded positive test results. The performance of the illumigene assay equals that of microscopy combined with RDT in the prospective panel with three false negative RDT results and one false negative microscopy result. Excellent concordance with PCR was observed. The limit of detection of the assay approached 0.5 parasites/µL for both P. falciparum and Plasmodium vivax.

Conclusion

In non-endemic regions where the diagnostic process for malaria infections is questioned by lack of experience and low levels of parasite densities, the illumigene assay can be of value. Due to its high sensitivity, the LAMP assay may be considered as primary diagnostic test. The results of this study indicate that negative screen results do not need further confirmation. However, before implementation, this approach needs to be confirmed in larger, prospective studies. A shortcoming of this assay is that no species identification nor determination of parasite density are possible.

Imported malaria in Spain (2009-2016): results from the +REDIVI Collaborative Network

Background

Imported malaria is a frequent diagnosis in travellers and migrants. The objective of this study was to describe the epidemiological and clinical characteristics of patients diagnosed with imported malaria within a Spanish collaborative network registering imported diseases (+REDIVI). In addition, the possible association between malaria and type of case, gender, age or area of exposure was explored.

Methods

Cases of imported malaria were identified among all cases registered in the +REDIVI database during the period October 2009–October 2016. Demographic, epidemiological and clinical characteristics were analysed.

Results

In total, 11,816 cases of imported infectious diseases were registered in +REDIVI’s database between October 2009 and October 2016. Immigrants seen for the first time after migration accounted for 60.2% of cases, 21.0% of patients were travellers, and 18.8% were travellers/immigrants visiting friends and relatives (VFRs). There were 850 cases of malaria (850/11,816, 7.2%). Malaria was significantly more frequent in men than in women (56.8% vs 43.2%) and in VFR-immigrants (52.6%) as compared to travellers (21.3%), immigrants (20.7%) and VFR-travellers (5.4%) (p < 0.001). Although this data was not available for most patients with malaria, only a minority (29/217, 13.4%) mentioned correct anti-malarial prophylaxis. Sub-Saharan Africa was found to be the most common region of acquisition of malaria. Most common reason for consultation after travel was a febrile syndrome although an important proportion of immigrants were asymptomatic and presented only for health screening (27.3%). Around 5% of travellers presented with severe malaria. The most prevalent species of Plasmodium diagnosed was Plasmodium falciparum (81.5%). Malaria due to Plasmodium ovale/Plasmodium vivax was frequent among travellers (17%) and nearly 5% of all malaria cases in immigrants were caused by Plasmodium malariae.

Conclusions

Malaria was among the five most frequent diagnoses registered in +REDIVI’s database. Some significant differences were found in the distribution of malaria according to gender, type of case, species. Among all malaria cases, the most frequent diagnosis was P. falciparum infection in VFR-immigrant men.

A generic method for improving the spatial interoperability of medical and ecological databases

BACKGROUND

The availability of big data in healthcare and the intensive development of data reuse and georeferencing have opened up perspectives for health spatial analysis. However, fine-scale spatial studies of ecological and medical databases are limited by the change of support problem and thus a lack of spatial unit interoperability. The use of spatial disaggregation methods to solve this problem introduces errors into the spatial estimations. Here, we present a generic, two-step method for merging medical and ecological databases that avoids the use of spatial disaggregation methods, while maximizing the spatial resolution.

METHODS

Firstly, a mapping table is created after one or more transition matrices have been defined. The latter link the spatial units of the original databases to the spatial units of the final database. Secondly, the mapping table is validated by (1) comparing the covariates contained in the two original databases, and (2) checking the spatial validity with a spatial continuity criterion and a spatial resolution index.

RESULTS

We used our novel method to merge a medical database (the French national diagnosis-related group database, containing 5644 spatial units) with an ecological database (produced by the French National Institute of Statistics and Economic Studies, and containing with 36,594 spatial units). The mapping table yielded 5632 final spatial units. The mapping table's validity was evaluated by comparing the number of births in the medical database and the ecological databases in each final spatial unit. The median [interquartile range] relative difference was 2.3% [0; 5.7]. The spatial continuity criterion was low (2.4%), and the spatial resolution index was greater than for most French administrative areas.

CONCLUSIONS

Our innovative approach improves interoperability between medical and ecological databases and facilitates fine-scale spatial analyses. We have shown that disaggregation models and large aggregation techniques are not necessarily the best ways to tackle the change of support problem.

Epidemiological and clinical assessment of a shared territorial malaria guideline in the 10 years of its implementation (Barcelona, North Metropolitan Area, Catalonia, Spain, 2007-2016)

BACKGROUND

Malaria remains a major source of morbi-mortality among travellers. In 2007, a consensual multicenter Primary Care-Hospital shared guideline on travel-prior chemoprophylaxis, diagnosis and clinical management of imported malaria was set up in the Barcelona North Metropolitan area. The aim of the study is to assess the evolution of malaria cases in the area as well as its clinical management over the 10 years of its implementation.

RESULTS

A total of 190 malaria cases, all them imported, have been recorded. The overall estimated malaria crude incidence was of 0.47 cases per 10,000 population/year (95% CI 0.34-0.59) with a slight significant positive slope especially at the expense of an increase in Indian sub-continent Plasmodium vivax cases. The number of patients who attended the pre-travel consultation was low (13.7%) as well as those with prescribed chemoprophylaxis (10%). Severe malaria was diagnosed in 34 (17.9%) patients and ICU admittance was required in 2.6% of them. Organ sequelae (two renal failures and one post-acute distress respiratory syndrome) were recorded in 3 patients at hospital discharge, although all three were recovered at 30 days. None of the patients died. Patients complying with severity criteria were significantly males (p = 0.04), came from Africa (p = 0.02), were mainly non-immigrant travellers (p = 0.01) and were attended in a hospital setting (p < 0.001). The most frequently identified species was Plasmodium falciparum (64.2%), P. vivax (23.2%), Plasmodium malariae (1.6%) and Plasmodium ovale (1.1%). Those patients diagnosed with P. falciparum malaria came more often from sub-Saharan Africa (p < 0.001) and those with P. vivax came largely from the Indian sub-continent (p = 0.003). Among the 126 patients in whom an immunochromatographic antigenic test was performed, the result was interpreted as falsely negative in 12.1% of them. False negative results can be related to cases with <1% parasitaemia.

CONCLUSIONS

After 10 years of surveillance, a moderate increase in malaria incidence was observed, mostly P. vivax cases imported from the Indian sub-continent. Although severe malaria cases have been frequently reported, none of the patients died and organ sequelae were rare. Conceivably, the participation of the Primary Care and the District and Third Level Hospital professionals defining surveillance, diagnostic tests, referral criteria and clinical management can be considered a useful tool to minimize malaria morbi-mortality.

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.

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.

Examination of the antimalarial potential of experimental aminoquinolines: poor in vitro effect does not preclude in vivo efficacy

Malaria remains a major disease in the developing world and globally is the most important parasitic disease causing significant morbidity and mortality. Because of widespread resistance to conventional antimalarials, including chloroquine (CQ), new drugs are urgently needed. Here we report on the antimalarial efficacy, both in vitro and in vivo, of a series of aminoquinoline derivatives with adamantane or benzothiophene as a carrier. In vitro efficacy was evaluated by a lactate dehydrogenase (LDH) assay in cultures of a CQ-sensitive (3D7) and CQ-resistant (Dd2) strain of Plasmodium falciparum. Of a series of 26 screened compounds, 12 that exerted a growth inhibition rate of ≥50% were further examined in vitro to determine the 50% inhibitory concentration (IC₅₀) values. Nine compounds shown in preliminary experiments to be non-toxic in vivo were evaluated in C57BL/6 mice infected with Plasmodium berghei ANKA strain using a modified Thompson test. All nine compounds examined in vivo prolonged the survival of treated versus untreated mice, four of which afforded ≥60% survival. Most notably, two of these compounds, both with the adamantane carrier, afforded complete cure (100% survival and parasite clearance). Interestingly, one of these compounds had no in vitro effect against the CQ-resistant P. falciparum strain. Better in vivo compared with in vitro results suggest a role for compound metabolites rather than the compounds themselves. The results presented here point to adamantane as a carrier that enhances the antimalarial potential of aminoquinolines.

Malaria in China, 2011-2015: an observational study

Objective

To ascertain the trends and burden of malaria in China and the costs of interventions for 2011–2015.

Methods

We analysed the spatiotemporal and demographic features of locally transmitted and imported malaria cases using disaggregated surveillance data on malaria from 2011 to 2015, covering the range of dominant malaria vectors in China. The total and mean costs for malaria elimination were calculated by funding sources, interventions and population at risk.

Findings

A total of 17 745 malaria cases, including 123 deaths (0.7%), were reported in mainland China, with 15 840 (89%) being imported cases, mainly from Africa and south-east Asia. Almost all counties of China (2855/2858) had achieved their elimination goals by 2015, and locally transmitted cases dropped from 1469 cases in 2011 to 43 cases in 2015, mainly occurring in the regions bordering Myanmar where Anopheles minimus and An. dirus are the dominant vector species. A total of United States dollars (US$) 134.6 million was spent in efforts to eliminate malaria during 2011–2015, with US$ 57.2 million (43%) from the Global Fund to Fight AIDS, Tuberculosis and Malaria and US$ 77.3 million (57%) from the Chinese central government. The mean annual investment (US$ 27 million) per person at risk (574 million) was US$ 0.05 (standard deviation: 0.03).

Conclusion

The locally transmitted malaria burden in China has decreased. The key challenge is to address the remaining local transmission, as well as to reduce imported cases from Africa and south-east Asia. Continued efforts and appropriate levels of investment are needed in the 2016–2020 period to achieve elimination.

Malaria Surveillance - United States, 2014

PROBLEM/CONDITION

Malaria in humans is caused by intraerythrocytic protozoa of the genus Plasmodium. These parasites are transmitted by the bite of an infective female Anopheles mosquito. The majority of malaria infections in the United States occur among persons who have traveled to regions with ongoing malaria transmission. However, malaria is occasionally acquired by persons who have not traveled out of the country through exposure to infected blood products, congenital transmission, laboratory exposure, or local mosquitoborne transmission. Malaria surveillance in the United States is conducted to identify episodes of local transmission and to guide prevention recommendations for travelers.

PERIOD COVERED

This report summarizes cases in persons with onset of illness in 2014 and trends during previous years.

DESCRIPTION OF SYSTEM

Malaria cases diagnosed by blood film, polymerase chain reaction, or rapid diagnostic tests are reported to local and state health departments by health care providers or laboratory staff. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System, National Notifiable Diseases Surveillance System, or direct CDC consultations. CDC conducts antimalarial drug resistance marker testing on blood samples submitted by health care providers or local or state health departments. Data from these reporting systems serve as the basis for this report.

RESULTS

CDC received reports of 1,724 confirmed malaria cases, including one congenital case and two cryptic cases, with onset of symptoms in 2014 among persons in the United States. The number of confirmed cases in 2014 is consistent with the number of confirmed cases reported in 2013 (n = 1,741; this number has been updated from a previous publication to account for delayed reporting for persons with symptom onset occurring in late 2013). Plasmodium falciparum, P. vivax, P. ovale, and P. malariae were identified in 66.1%, 13.3%, 5.2%, and 2.7% of cases, respectively. Less than 1.0% of patients were infected with two species. The infecting species was unreported or undetermined in 11.7% of cases. CDC provided diagnostic assistance for 14.2% of confirmed cases and tested 12.0% of P. falciparum specimens for antimalarial resistance markers. Of patients who reported purpose of travel, 57.5% were visiting friends and relatives (VFR). Among U.S. residents for whom information on chemoprophylaxis use and travel region was known, 7.8% reported that they initiated and adhered to a chemoprophylaxis drug regimen recommended by CDC for the regions to which they had traveled. Thirty-two cases were among pregnant women, none of whom had adhered to chemoprophylaxis. Among all reported cases, 17.0% were classified as severe illness, and five persons with malaria died. CDC received 137 P. falciparum-positive samples for the detection of antimalarial resistance markers (although some loci for chloroquine and mefloquine were untestable for up to nine samples). Of the 137 samples tested, 131 (95.6%) had genetic polymorphisms associated with pyrimethamine drug resistance, 96 (70.0%) with sulfadoxine resistance, 77 (57.5%) with chloroquine resistance, three (2.3%) with mefloquine drug resistance, one (<1.0%) with atovaquone resistance, and two (1.4%) with artemisinin resistance.

INTERPRETATION

The overall trend of malaria cases has been increasing since 1973; the number of cases reported in 2014 is the fourth highest annual total since then. Despite progress in reducing global prevalence of malaria, the disease remains endemic in many regions and use of appropriate prevention measures by travelers is still inadequate.

PUBLIC HEALTH ACTION

Completion of data elements on the malaria case report form increased slightly in 2014 compared with 2013, but still remains unacceptably low. In 2014, at least one essential element (i.e., species, travel history, or resident status) was missing in 21.3% of case report forms. Incomplete reporting compromises efforts to examine trends in malaria cases and prevent infections. VFR travelers continue to be a difficult population to reach with effective malaria prevention strategies. Evidence-based prevention strategies that effectively target VFR travelers need to be developed and implemented to have a substantial impact on the number of imported malaria cases in the United States. Fewer U.S. resident patients reported taking chemoprophylaxis in 2014 (27.2%) compared with 2013 (28.6%), and adherence was poor among those who did take chemoprophylaxis. Proper use of malaria chemoprophylaxis will prevent the majority of malaria illnesses and reduce risk for severe disease (https://www.cdc.gov/malaria/travelers/drugs.html). Malaria infections can be fatal if not diagnosed and treated promptly with antimalarial medications appropriate for the patient's age and medical history, likely country of malaria acquisition, and previous use of antimalarial chemoprophylaxis. Recent molecular laboratory advances have enabled CDC to identify and conduct molecular surveillance of antimalarial drug resistance markers (https://www.cdc.gov/malaria/features/ars.html) and improve the ability of CDC to track, guide treatment, and manage drug resistance in malaria parasites both domestically and globally. For this effort to be successful, specimens should be submitted for all cases diagnosed in the United States. Clinicians should consult CDC Guidelines for Treatment of Malaria in the United States and contact the CDC Malaria Hotline for case management advice, when needed. Malaria treatment recommendations can be obtained online at https://www.cdc.gov/malaria/diagnosis_treatment/ or by calling the Malaria Hotline at 770-488-7788 or toll-free at 855-856-4713.

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

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