Imported malaria in Finland 1995 to 2008: an overview of surveillance, travel trends, and antimalarial drug sales

The imported infections among foreign travelers in China: an observational study

BACKGROUND

In the past few decades, globalization has rendered more frequent and intensive population movement between countries, which has changed the original disease spectrum and brought a huge health impact on the global population including China. This study aims to describe the spectrum and epidemiological characteristics of imported infections among foreign travelers travelling to China.

METHODS

The data on imported infections among foreign travelers were obtained from Custom Inbound Screening System (CISS) and the National Notifiable Infectious Disease Reporting System (NNIDRS). All the infections were classified into respiratory, gastrointestinal, vector-borne, blood/sex-transmitted and mucocutaneous diseases, of which case numbers and incidences were calculated and the proportions were compared among subgroups.

RESULTS

In total, 17,189 travelers diagnosed with 58 imported infectious diseases were reported from 2014 to 2018, with an overall incidence of 122.59 per million. Respiratory infection (7,351 cases, mainly influenza) and blood/sex-transmitted diseases (6,114 cases mainly Hepatitis B and HIV infection) were the most frequently diagnosed diseases, followed by vector-borne infections (3,128 cases, mainly dengue fever and malaria). The highest case number was from Asia and Europe, while the highest incidence rate was from Africa (296.00 per million). When specific diagnosis was compared, both the highest absolute case number and incidence were observed for influenza. An obvious seasonal pattern was observed for vector-borne diseases, with the annual epidemic spanning from July to November. The origin-destination matrices disclosed the movement of imported infection followed specific routes.

CONCLUSIONS

Our study provided a profile of infectious diseases among foreign travelers travelling to China and pinpointed the target regions, seasons and populations for prevention and control, to attain an informed control of imported infections in China.

Drug interactions with antimalarial medications in older travelers: a clinical guide

Increasingly older adults are traveling to international destinations with malaria as a present risk. Surveillance systems indicate that older adults are more likely to suffer severe complications from malaria. The role of health care providers in selecting an appropriate medication for chemoprophylaxis or treatment of malaria in adults becomes more difficult as older adults undergo physiologic changes that alter the pharmacokinetic and pharmacodynamic nature of medications potentially causing increased drug interactions, adverse events and altered drug action. A comprehensive literature search from 1970 to present, with a focus on the past 10 years, was conducted on drug interactions, pharmacokinetic and pharmacodynamic effects on antimalarials in adults. It was determined that due to pharmacodynamic and pharmacokinetic changes in older adults, especially renal and cardiovascular, special attention should be given to this population of travelers in order to minimize the likelihood of adverse events or altered drug efficacy. Antimalarial drug-disease interactions in older adults can occur more often due to QT prolongation, exacerbation of hypoglycemia, decreased renal elimination and decreased hepatic metabolism. Older antimalarials have well-documented drug-drug interactions. Tafenoquine, a new antimalarial, requires glucose-6-phosphate dehydrogenase screening like primaquine and monitoring of new potential drug interaction with MATE1 and OCT2 substrates. While drug-drug interactions in older travelers may occur more often as a result of polypharmacy, data did not indicate adverse reactions or decreased drug efficacy is greater compared with younger adults. Overall, with the exception of recently approved tafenoquine, much is known about antimalarial drug and disease interactions, but new drugs are always being approved, requiring travel health providers to understand the pharmacokinetics and pharmacodynamics of antimalarial drugs to predict the impact on safety and efficacy in travelers. This guide provides travel health providers with valuable insights on potential outcomes associated with drug interactions in adults and recommended monitoring or drug regimen modification.

Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings

BACKGROUND

Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings.

METHODS

We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians.

RESULTS

A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection.

CONCLUSIONS

This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases.

Destination specific risks of acquisition of notifiable food- and waterborne infections or sexually transmitted infections among Finnish international travellers, 1995-2015

BACKGROUND

Overnight international travels made by Finns more than doubled during 1995-2015. To estimate risks and observe trends of travel-related notifiable sexually transmitted and food- and water-borne infections (STIs and FWIs) among travellers, we analysed national reports of gonorrhoea, syphilis, hepatitis A, shigellosis, campylobacteriosis and salmonellosis cases and related them to travel statistics.

METHOD

Cases notified as travel-related to the Finnish infectious diseases register were used as numerators and overnight stays of Statistics Finland surveys as denominator. We calculated overall risks (per 100,000 travellers) and assessed trends (using regression model) in various geographic regions.

RESULTS

Of all travel-related cases during 1995-2015, 2304 were STIs and 70,929 FWIs. During 2012-2015, Asia-Oceania showed highest risk estimates for gonorrhoea (11.0; 95%CI, 9.5-13), syphilis (1.4; 0.93-2.1), salmonellosis (157; 151-164), and campylobacteriosis (135; 129-141), and Africa for hepatitis A (4.5; 2.5-7.9), and shigellosis (35; 28-43). When evaluating at country level, the highest risks of infections was found in Thailand, except for hepatitis A ranking Hungary the first. During 2000-2011, significantly decreasing trends occurred for most FWIs particularly in the European regions and for STIs in Russia-Baltics.

CONCLUSIONS

Our findings can be used in targeting pre-travel advice, which should also cover those visiting Thailand or European hepatitis A risk areas.

Malaria in a tertiary hospital in Singapore--clinical presentation, treatment and outcome: an eleven year retrospective review

BACKGROUND

Malaria remains a global health threat and poses significant health risks even in non-endemic regions like Singapore.

METHODS

A retrospective analysis of 214 patients with smear-positive malaria treated at Singapore General Hospital (SGH) between year 2000 and 2010.

RESULTS

One hundred and sixty-seven (78%) patients were male; median age was 35 y (range, 25–52 y). Sixty-four (41%) patients had past history of treated malaria. Seven (4.9%) patients did not travel out of Singapore. One hundred and twenty-seven (76.5%) cases of malaria were acquired in Southeast Asia (SEA) and the Indian subcontinent. There were 127 (59.3%) Plasmodium vivax, 83 (38.8%) Plasmodium falciparum, 1 (0.3%) Plasmodium malariae and 3 (1.4%) mixed infections. Fever was the most common symptom and thrombocytopaenia was the most common laboratory finding. There were 43 severe and 171 uncomplicated cases of malaria, including 8 severe P. vivax cases. Those with severe malaria were older, stayed longer in hospital, had a higher percentage parasitaemia and took longer to clear the parasite. The diagnosis of malaria was suspected at the first contact with healthcare provider in 194 (91.9%) cases. Sixty-one (85.9%) patients with P. falciparum infection received combination anti-malarial therapy and 109 (98.2%) of patients with P. vivax received primaquine for hypnozoite clearance in combination with schizontocidal agent. All the patients survived.

CONCLUSION

In this study, P. vivax was the most common cause of malaria. Severe P. vivax was not uncommon. Cryptic transmission of malaria exists, highlighting the importance of continued vigilance, malaria surveillance and vector control. Early recognition of malaria improved the overall outcome.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Imported malaria in Finland 2003-2011: prospective nationwide data with rechecked background information

BACKGROUND

Although described in several reports, imported malaria in Europe has not been surveyed nationwide with overall coverage of patients and individually rechecked background information. Plasmodium falciparum infections have been reported despite regularly taken appropriate chemoprophylaxis, yet the reliability of such questionnaire-based retrospective data has been questioned. This was the starting-point for conducting a prospective nationwide survey of imported malaria where compliance data was double-checked.

METHODS

Data was collected on all cases of imported malaria confirmed and recorded by the reference laboratory of Finland (population 5.4 million) from 2003 to 2011, and these were compared with those reported to the National Infectious Disease Register (NIDR). Background information was gathered by detailed questionnaires sent to the clinicians upon diagnosis; missing data were enquired by telephone of clinician or patient. Special attention was paid to compliance with chemoprophylaxis: self-reported use of anti-malarials was rechecked for all cases of P. falciparum.

RESULTS

A total of 265 malaria cases (average annual incidence rate 0.5/100,000 population) had been recorded by the reference laboratory, all of them also reported to NIDR: 54% were born in malaria-endemic countries; 86% were currently living in non-endemic regions. Malaria was mainly (81%) contracted in sub-Saharan Africa. Plasmodium falciparum proved to be the most common species (72%). Immigrants constituted the largest group of travellers (44%). Pre-travel advice was received by 20% of those born in endemic regions and 81% of those from non-endemic regions. Of those with P. falciparum, 4% reported regular use of appropriate chemoprophylaxis (mefloquine or atovaquone/proguanil or doxycycline for regions with chloroquine-resistant and atovaquone/proguanil or doxycycline for regions with mefloquine-resistant P. falciparum); after individual rechecking, however, it was found that none of them had been fully compliant.

CONCLUSIONS

Information on compliance with chemoprophylactic regimen cannot be relied on, and it should be rechecked if malaria is suspected. The results of the present study suggest that mefloquine, atovaquone/proguanil and doxycycline are effective as chemoprophylaxis against P. falciparum malaria, when taken conscientiously.

Elimination therapy for the endemic malarias

Most malaria diagnosed outside endemic zones occurs in patients experiencing the consequences of what was likely a single infectious bite by an anopheline mosquito. A single species of parasite is nearly always involved and expert opinion on malaria chemotherapy uniformly prescribes species- and stage-specific treatments. However the vast majority of people experiencing malaria, those resident in endemic zones, do so repeatedly and very often with the involvement of two or more species and stages of parasite. Silent forms of these infections-asymptomatic and beyond the reach of diagnostics-may accumulate to form substantial and unchallenged reservoirs of infection. In such settings treating only the species and stage of malaria revealed by diagnosis and not others may not be sensible or appropriate. Developing therapeutic strategies that address all species and stages independently of diagnostic evidence may substantially improve the effectiveness of the control and elimination of endemic malaria.

Migration and malaria in europe

The proportion of imported malaria cases due to immigrants in Europe has increased during the lasts decades, with higher rates associated with settled immigrants who travel to visit friends and relatives (VFRs) in their country of origin. Cases are mainly due to P. falciparum and Sub-Saharan Africa is the most common origin. Clinically, malaria in immigrants is characterised by a mild clinical presentation including asymptomatic or delayed malaria cases and low parasitic levels. These characteristics may be explained by a semi-immunity acquired after long periods of time exposed to stable malaria transmission. Malaria cases among immigrants, even asymptomatic patients with sub-microscopic parasitemia, could increase the risk of transmission and cause the reintroduction of malaria in certain areas that have adequate vectors and climate conditions. Moreover, imported malaria cases in immigrants can also play an important role in the non-vector transmission out of endemic areas, through blood transfusions, organ transplantation or congenital transmission or occupational exposures. Consequently, outside of endemic areas, malaria screening should be carried out among recently arrived immigrants coming from malaria endemic countries. The aim of screening is to reduce the risk of clinical malaria in the individual as well as to prevent autochthonous transmission of malaria in areas where it has been eradicated.

Epidemiology of imported malaria among children and young adults in Barcelona (1990-2008)

Background

Increasing international travel and migration is producing changes in trends in infectious diseases, especially in children from many European cities. The objective of this study was to describe the epidemiology and determine the trends of imported malaria in patients under 20 years old in the city of Barcelona, Spain, during an 18-year period.

Methods

The study included malaria cases that were laboratory confirmed and reported to the malaria register at the Public Health Agency of Barcelona from 1990 to 2008, residing in Barcelona and less than 20 years old. Patients were classified as natives (born in Spain) or immigrants. Differences in the distribution of demographic, clinical characteristics, and incidence per 100,000 person-year evolution were analysed. Natives and immigrants were compared by logistic regression by calculating the odds ratio (OR) with a 95% confidence interval (CI) and Chi-square for a linear trend (p < 0.05).

Results

Of the total 174 cases, 143 (82.1%) were immigrants, 100 (57.5%) were female, 121 (69.5%) Plasmodium falciparum, and 108 (62.1%) were visiting friends and relatives (VFR) as the reason for travel. Among the immigrants, 99 (67.8%) were from Equatorial Guinea. Immigrant cases more frequently travelled to Africa than natives (p = 0.02). The factors associated with imported malaria among immigrant residents was travelling for VFR (OR: 6.2 CI 1.9-20.2) and age 15-19 (OR: 3.7 CI 1-13.3). The incidence increased from 1990 to 1999 (p < 0.001) and decreased from 2000 to 2008 (p = 0.01), although the global linear trend was not statistically significant (p = 0.41). The fatality rate was 0.5%.

Conclusions

The majority of cases of malaria in population less than 20 years in Barcelona were immigrants, travelling to Africa for VFR and Plasmodium falciparum was most frequently detected. The trend analysis of the entire study period did not show a statistically significant decline. It is recommended to be aware of malaria, especially among children of immigrants who travel to their parent's home country for VFR. Better access to pre travel advice should be provided.

High rates of malaria among US military members born in malaria-endemic countries, 2002-2010

To estimate malaria rates in association with birth country, we analyzed routine surveillance data for US military members. During 2002-2010, rates were 44× higher for those born in western Africa than for those born in the United States. Loss of natural immunity renders persons susceptible when visiting birth countries. Pretravel chemoprophylaxis should be emphasized.

Fever in travelers returning from malaria-endemic areas: don't look for malaria only

BACKGROUND

Returning travelers with fever pose challenges for clinicians because of the multitude of diagnostic alternatives. Case data in a Finnish tertiary hospital were analyzed in order to define the causes of fever in returned travelers and to evaluate the current diagnostic approach.

METHODS

A retrospective study of patient records comprised 462 febrile adults who, after traveling in malaria-endemic areas, were admitted to the Helsinki University Central Hospital (HUCH) emergency room from 2005 to 2009. These patients were identified through requests for malaria smear.

RESULTS

The most common groups of diagnoses were acute diarrheal disease (126 patients/27%), systemic febrile illness (95/21%), and respiratory illness (69/15%). The most common specific main diagnosis was Campylobacter infection (40/9%). Malaria was diagnosed in 4% (20/462). Blood culture was positive for bacteria in 5% of those tested (21/428). Eight patients were diagnosed with influenza. HIV-antibodies were tested in 174 patients (38%) and proved positive in 3% of them (5/174, 1% of all patients). The cause of fever was noninfectious in 12 (3%), remaining unknown in 116 (25%). Potentially life-threatening illnesses were diagnosed in 118 patients (26%), the strongest risk factors were baseline C-reactive protein (CRP) ≥100 (OR 3.6; 95% CI 2.0-6.4) and platelet count ≤140 (OR 3.8; 95% CI 2.0-7.3). Nine patients (2%) were treated in high dependency or intensive care units; one died of septicemia. Forty-five patients (10%) had more than one diagnosis.

CONCLUSION

The high proportion of patients with more than one diagnosis proves the importance of careful diagnostics. Every fourth returning traveler with fever had a potentially life-threatening illness. Septicemia was as common as malaria. The proportion of HIV cases exceeded the prevalence in population for which Centers for Disease Control and Prevention, USA (CDC) recommends routine HIV testing. Both blood cultures and HIV tests should be considered in febrile travelers.

International travel increase and malaria importation in Romania, 2008-2009

OBJECTIVES

This report aims to assess the epidemiological characteristics of imported malaria in Romania in the context of international travel increase, and to compare them with the data reported by other European countries.

METHODS

Data on malaria cases were provided by the National Centre for Surveillance and Control of the Communicable Disease, whereas the data regarding international travels to and from Romania were retrieved from the Romanian Statistical Yearbook.

RESULTS

The number of Romanian citizens who traveled to Africa in 2007 increased by over 600% as compared to the previous year. During the years 2008-2009, 25 cases of imported malaria were registered in Romania, with no fatalities. All patients were male and most of them (84%) acquired the infection in Africa. Plasmodium falciparum was involved in 68% of cases. The majority of the affected patients (41%) were aged 31 to 40 years. Labor was the main reason for traveling (72%), and 92% of cases took either partial or no chemoprophylaxis.

CONCLUSION

The continuous growth of professional and leisure voyages to malaria-endemic regions may lead to a dramatic increase of imported cases, especially if prophylactic measures are not strictly followed.

Malaria prophylaxis in African and Asiatic children traveling to their parents' home country: a Florentine Study

BACKGROUND

The majority of malaria cases in Europe occur in immigrated adults and children settled in nonendemic countries but who had traveled to their home country to visit friends and relatives.

METHODS

We carried out a study on a sample of 71 parents immigrated from high-risk countries to investigate awareness of malaria risk and use of pharmacological and nonpharmacological (repellents, insecticides, nets, and insecticide-treated nets) prophylaxis. A questionnaire was administered to a convenience sample of immigrant parents who presented their children for acute care to the Emergency Department, Anna Meyer Children's University Hospital, Florence, Italy between August and November 2009.

RESULTS

Fifty-nine out of 71 (83.1%) parents were aware of malaria risk in their native country. Forty-one (57.7%) children had traveled to their parents' home country. Nonpharmacological prophylaxis was used in 30 (73.1%) children. Eight (19.5%) children had received pharmacological prophylaxis, the mostly used drug being mefloquine in six out of eight (75%) patients. Seven out of eight (87.5%) children completed prophylaxis appropriately. Adverse drug reaction was reported in one (12.5%) patient. While abroad, eight (19.5%) parents and one (2.4%) child reported to have developed malaria. A significantly higher proportion of children traveling to Africa compared to children traveling to Asia (5/11 = 46% vs 3/30 = 10%, p = 0.036) had received pharmacological prophylaxis.

CONCLUSIONS

Our data highlight the need for educational actions in Italy about malaria prophylaxis among immigrants. Larger epidemiological investigations are needed at this regard.

Malaria in paradise: characterization of imported cases in Gran Canaria Island (1993-2006)

BACKGROUND

Spain obtained the official certificate of malaria eradication in 1964. However, imported malaria cases have been increasing during the last few decades in this country. This study aims to describe the clinical and epidemiological features of patients diagnosed with malaria on Gran Canaria Island.

METHODS

A retrospective study was conducted based on case review of all patients diagnosed with malaria microbiologically confirmed from 1993 to 2006, at the three referral teaching hospitals on Gran Canaria Island.

RESULTS

One hundred eighty-four episodes in 181 patients were diagnosed, 170 of them were analyzed. Most of them (82%) were travelers. Nearly 15% (14.7%) declared having had some chemoprophylaxis, but only half of them completed the treatment. Twenty cases (10.9%) were diagnosed who had just arrived as immigrants, mainly children. Malaria was acquired in Africa by 94.7% of the cases and Plasmodium falciparum was responsible for the majority of the cases (84.1%). Clinical and epidemiological differences were observed among different groups of patients formed by their origin and travel purposes. At least one indicator of severe malaria was established in 22.9% of the cases. However, global mortality was 3.8%.

CONCLUSIONS

Malaria in Gran Canaria Island is imported from endemic areas, mainly from African countries, observed mostly among young adult males, but clinical and epidemiological features may change among different groups of patients. The number of immigrants diagnosed with malaria is increasing in this area nowadays.

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.