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

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

BACKGROUND

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

CASE PRESENTATION

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

DISCUSSION

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

CONCLUSIONS

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

Geographic clustering of travel-acquired infections in Ontario, Canada, 2008-2020

As the frequency of international travel increases, more individuals are at risk of travel-acquired infections (TAIs). In this ecological study of over 170,000 unique tests from Public Health Ontario's laboratory, we reviewed all laboratory-reported cases of malaria, dengue, chikungunya, and enteric fever in Ontario, Canada between 2008-2020 to identify high-resolution geographical clusters for potential targeted pre-travel prevention. Smoothed standardized incidence ratios (SIRs) and 95% posterior credible intervals (CIs) were estimated using a spatial Bayesian hierarchical model. High- and low-incidence areas were described using data from the 2016 Census based on the home forward sortation area of patients testing positive. A second model was used to estimate the association between drivetime to the nearest travel clinic and incidence of TAI within high-incidence areas. There were 6,114 microbiologically confirmed TAIs across Ontario over the study period. There was spatial clustering of TAIs (Moran's I = 0.59, p<0.0001). Compared to low-incidence areas, high-incidence areas had higher proportions of immigrants (p<0.0001), were lower income (p = 0.0027), had higher levels of university education (p<0.0001), and less knowledge of English/French languages (p<0.0001). In the high-incidence Greater Toronto Area (GTA), each minute increase in drive time to the closest travel clinic was associated with a 3% reduction in TAI incidence (95% CI 1-6%). While urban neighbourhoods in the GTA had the highest burden of TAIs, geographic proximity to a travel clinic in the GTA was not associated with an area-level incidence reduction in TAI. This suggests other barriers to seeking and adhering to pre-travel advice.

Access, utilization, and barriers to using malaria protection tools in migrants to Iran

Background

Imported malaria cases could be considered one of the threats to malaria elimination. Therefore, increasing migrants’ access to malaria preventive measures can play an essential role in maintaining appropriate conditions and preventing malaria outbreaks. This study aimed to provide detailed information about access, utilization, and barriers to using malaria protection tools in migrants to Iran.

Methods

This study was conducted in a vast region consisting of 4 provinces and 38 cities located in the south and southeast of the country. Study participants were migrants who moved to the study area in the past three months. A sample of 4163 migrants participated in the study. They were selected through a multi-stage sampling method to obtain a representative community sample. Data were collected through interviewer-administered questionnaires about participants’ socio-demographic specification, commuting characteristics, travel aim, access, ways of preparing, and reasons to use or not to use malaria protection tools. Quantitative and qualitative variables were described and analyzed finally.

Results

The mean age of individuals was 28.6 ± 10.8, with a range of 3–88 years old. Migrants’ country of origin was Afghanistan (56.6%), Pakistan (38.4%), and Iran (5%). Most migrants (69.2%) did not have malaria protection tools while staying in Iran. Among those who procured the protection tools, 74% used long-lasting insecticidal nets (LLINs), 13.4% used mosquito repellent sticks and coil, and 12.7% did not use any tools. Respectively, lack of knowledge about where they can get LLINs, followed by being expensive, unavailability in the market, not cooperation of health officer, and no need to use were expressed as the causes for having no access. The main reasons for non-using the tools were lack of knowledge about their application, followed by a defect in protection tools, ineffectiveness, and being harmful, respectively. Migrants who were supported by an employer accessed more to LLINs.

Conclusions

This study reveals significant shortcomings in knowledge, access, and utilization of malaria protection tools among migrants in Iran. Inequitable access to public health services is predictable during migration; however, access to sustainable protection tools is recommended.

Imported Malaria in Portugal: Prevalence of Polymorphisms in the Anti-Malarial Drug Resistance Genes pfmdr1 and pfk13

Malaria is one of the ‘big three’ killer infectious diseases, alongside tuberculosis and HIV. In non-endemic areas, malaria may occur in travelers who have recently been to or visited endemic regions. The number of imported malaria cases in Portugal has increased in recent years, mostly due to the close relationship with the community of Portuguese language countries. Samples were collected from malaria-infected patients attending Centro Hospitalar Lisboa Ocidental (CHLO) or the outpatient clinic of Instituto de Higiene e Medicina Tropical (IHMT-NOVA) between March 2014 and May 2021. Molecular characterization of Plasmodium falciparum pfk13 and pfmdr1 genes was performed. We analyzed 232 imported malaria cases. The majority (68.53%) of the patients came from Angola and only three patients travelled to a non-African country; one to Brazil and two to Indonesia. P. falciparum was diagnosed in 81.47% of the cases, P. malariae in 7.33%, P. ovale 6.47% and 1.72% carried P. vivax. No mutations were detected in pfk13. Regarding pfmdr1, the wild-type haplotype (N86/Y184/D1246) was also the most prevalent (64.71%) and N86/184F/D1246 was detected in 26.47% of the cases. The typical imported malaria case was middle-aged male, traveling from Angola, infected with P. falciparum carrying wild type pfmdr1 and pfk13. Our study highlights the need for constant surveillance of malaria parasites imported into Portugal as an important pillar of public health.

Success of malaria chemoprophylaxis for outbound civil and military travellers in prevention of reintroduction of malaria in Sri Lanka

BACKGROUND

Sri Lanka was certified as malaria-free in September 2016. However, the continuous presence of the malaria vector poses serious risks of reintroduction of the disease. Chemoprophylaxis and advice on malaria preventive behaviour for international travellers is a key strategy adopted to reduce the risk of imported malaria.

METHODS

We conducted an efficiency study of malaria chemoprophylaxis for civilian and military travellers who requested travel advice from the Anti Malaria Campaign (AMC) prior to departure. The AMC is the only agency that can issue malaria chemoprophylaxis to travellers and hence this sample is representative of all such individuals seeking travel advice in Sri Lanka.

RESULTS

A total of 544 (400 civilians and 144 military) travellers were interviewed prior to departure and after return. The majority travelled to African destinations (516/544 [94.8%]) and were prescribed mefloquine (517/544 [95%]). Chemoprophylaxis was well tolerated and discontinuation due to adverse events was minimal. Regular chemoprophylaxis was reported by 505 (92.8%) participants while overseas. The protective efficacy of chemoprophylaxis was 100% among those who complied with the full course.

CONCLUSIONS

The compliance with chemoprophylaxis and its protective efficacy were satisfactory in this study. It is an effective tool in preventing imported malaria to post-elimination Sri Lanka.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Severity and mortality of severe Plasmodium ovale infection: A systematic review and meta-analysis

Plasmodium ovale can infect humans, causing malaria disease. We aimed to investigate the severity and mortality of severe P. ovale infection to increase the awareness of physicians regarding the prognosis of this severe disease and outcome-related deaths in countries in which this disease is endemic. Articles that were published in the PubMed, Scopus, and ISI Web of Science databases prior to January 5, 2020 and reported the prevalence of severe P. ovale infection were systematically searched and reviewed. Studies that mainly reported severe P. ovale infection according to the 2014 WHO criteria for the treatment of malaria were included. Two reviewers selected, identified, assessed, and extracted data from studies independently. The pooled prevalence of severe P. ovale mono-infections was estimated using the command “metaprop case population, random/fixed”, which yielded the pooled estimate, 95% confidence interval (CI) and the I² value, indicating the level of heterogeneity. Meta-analyses of the proportions were performed using a random-effects model to explore the different proportions of severity between patients with P. ovale and those with other Plasmodium species infections. Among the eight studies that were included and had a total of 1,365 ovale malaria cases, the pooled prevalence of severe P. ovale was 0.03 (95% CI = 0.03–0.05%, I² = 54.4%). Jaundice (1.1%), severe anemia (0.88%), and pulmonary impairments (0.59%) were the most common severe complications found in patients infected with P. ovale. The meta-analysis demonstrated that a smaller proportion of patients with P. ovale than of patients with P. falciparum had severe infections (P-value = 0.01, OR = 0.36, 95% CI = 0.16–0.81, I² = 72%). The mortality rate of severe P. ovale infections was 0.15% (2/1,365 cases). Although severe complications of P. ovale infections in patients are rare, it is very important to increase the awareness of physicians regarding the prognosis of severe P. ovale infections in patients, especially in a high-risk population.

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

Background

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

Methods

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

Results

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

Conclusions

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

Imported Malaria in Countries where Malaria Is Not Endemic: a Comparison of Semi-immune and Nonimmune Travelers

The continuous increase in long-distance travel and recent large migratory movements have changed the epidemiological characteristics of imported malaria in countries where malaria is not endemic (here termed non-malaria-endemic countries). While malaria was primarily imported to nonendemic countries by returning travelers, the proportion of immigrants from malaria-endemic regions and travelers visiting friends and relatives (VFRs) in malaria-endemic countries has continued to increase. VFRs and immigrants from malaria-endemic countries now make up the majority of malaria patients in many nonendemic countries. Importantly, this group is characterized by various degrees of semi-immunity to malaria, resulting from repeated exposure to infection and a gradual decline of protection as a result of prolonged residence in non-malaria-endemic regions. Most studies indicate an effect of naturally acquired immunity in VFRs, leading to differences in the parasitological features, clinical manifestation, and odds for severe malaria and clinical complications between immune VFRs and nonimmune returning travelers. There are no valid data indicating evidence for differing algorithms for chemoprophylaxis or antimalarial treatment in semi-immune versus nonimmune malaria patients. So far, no robust biomarkers exist that properly reflect anti-parasite or clinical immunity. Until they are found, researchers should rigorously stratify their study results using surrogate markers, such as duration of time spent outside a malaria-endemic country.

Fever in the Returned Traveler

International travel is associated with a risk of infections not typically seen in high-income settings. Malaria is the most important tropical infection in travelers, but epidemics of dengue, chikungunya, and Zika emphasize that clinicians need to be aware of the rapidly changing distribution of many arboviruses. A detailed travel history and a syndromic approach to the investigation and management of patients is key. Consultation with a specialist is often recommended to ensure that appropriate management and investigations are undertaken in febrile returned travelers.

•

Travel, especially to low-income regions, is associated with an increased risk of infections not typically seen in high-income countries (e.g., malaria, enteric fever, dengue, chikungunya, Zika, and schistosomiasis).

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Although gastroenteritis, respiratory tract infections, and self-limiting viral infections are common, a minority of patients will have a potentially life-threatening tropical infection.

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The evaluation of an ill returned traveler requires a detailed travel history with an understanding of the geographic distribution of infections, risk factors for acquisition, incubation periods, clinical presentations, and appropriate laboratory investigations.

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A syndromic approach to specific investigations, and to presumptive therapy pending laboratory confirmation of the diagnosis, is appropriate.

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Travel is also a risk factor for acquisition of antimicrobial-resistant bacteria, such as those containing extended spectrum β-lactamases, that become part of the traveler's colonizing flora.

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As a rule, malaria should be excluded in all travelers presenting with a fever who have visited the tropics.

Non-adherence to malaria prophylaxis: The influence of travel-related and psychosocial factors

BACKGROUND

The effectiveness of malaria chemoprophylaxis is limited by a lack of compliance in travellers. This study assesses the demographic, travel-related, and psychosocial determinants of non-compliance with chemoprophylaxis.

METHODS

715 adults, who received a pre-travel malaria prophylaxis prescription, were invited to complete a post-travel digital questionnaire on non-compliance, demographics, travel-related and psychosocial variables.

RESULTS

330 travellers (53% response) reported 32% non-compliance with malaria chemoprophylaxis. Logistic regression analyses revealed that 3/11 assessed psychosocial variables uniquely predicted non-compliance: 'negative attitude towards chemoprophylaxis' (β=0.694, OR 2.0, p<0.01), 'low perceived severity of malaria' (β=0.277, p=0.04) and 'fatigue during travel' (β=2.225, OR 9.3, p<0.01). Furthermore, the age and education of the traveller were uniquely predictive of non-compliance (β=-0.023 (p=0.02) and β=0.684 (p=0.04)). None of the travel-related variables predicted non-compliance.

CONCLUSIONS

About one-third of the travellers in our study were non-compliant with malaria prophylaxis, especially young travellers and highly educated travellers. Fatigue during travel seems to lead to non-compliance. Further research should focus on addressing the psychosocial factors in pre-travel consultation, since these appear to be better predictors for intention to comply than travel-related variables.

New guidelines for the prevention of imported malaria in France

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

Imported cases of malaria in Spain: observational study using nationally reported statistics and surveillance data, 2002-2015

Background

Malaria was eliminated in Spain in 1964. Since then, more than 10,000 cases of malaria have been reported, mostly in travellers and migrants, making it the most frequently imported disease into this country. In order to improve knowledge on imported malaria cases characteristics, the two main malaria data sources were assessed: the national surveillance system and the hospital discharge database (CMBD).

Methods

Observational study using prospectively gathered surveillance data and CMBD records between 2002 and 2015. The average number of hospitalizations per year was calculated to assess temporal patterns. Socio-demographic, clinical and travel background information were analysed. Bivariate and multivariable statistical methods were employed to evaluate hospitalization risk, fatal outcome, continent of infection and chemoprophylaxis failure and their association with different factors.

Results

A total of 9513 malaria hospital discharges and 7421 reported malaria cases were identified. The number of reported cases was below the number of hospitalizations during the whole study period, with a steady increase trend in both databases since 2008. Males aged 25–44 were the most represented in both data sources. Most frequent related co-diagnoses were anaemia (20.2%) and thrombocytopaenia (15.4%). The risks of fatal outcome increased with age and were associated with the parasite species (Plasmodium falciparum). The main place of infection was Africa (88.9%), particularly Equatorial Guinea (33.2%). Most reported cases were visiting friends and relatives (VFRs) and immigrants (70.2%). A significant increased likelihood of hospitalization was observed for children under 10 years (aOR:2.7; 95% CI 1.9–3.9), those infected by Plasmodium vivax (4.3; 95% CI 2.1–8.7) and travellers VFRs (1.4; 95% CI 1.1–1.7). Only 4% of cases reported a correct regime of chemoprophylaxis. Being male, over 15 years, VFRs, migrant and born in an endemic country were associated to increased risk of failure in preventive chemotherapy.

Conclusions

The joint analysis of two data sources allowed for better characterization of imported malaria profile in Spain. Despite the availability of highly effective preventive measures, the preventable burden from malaria is high in Spain. Pre-travel advice and appropriately delivered preventive messages needs to be improved, particularly in migrants and VFRs.

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

IMPORTANCE

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

OBJECTIVE

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

DESIGN, SETTING, AND PARTICIPANTS

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

MAIN OUTCOMES AND MEASURES

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

Characterization of Plasmodium ovale spp. imported from Africa to Henan Province, China

As indigenous malaria has decreased over recent decades, the increasing number of imported malaria cases has provided a new challenge for China. The proportion of imported cases due to Plasmodium ovale has increased during this time, and the difference between P. ovale curtisi and P. ovale wallikeri is of importance. To better understand P. ovale epidemiology and the differences between the two subspecies, information on imported malaria in Henan Province was collected during 2010–2017. We carried out a descriptive study to analyze the prevalence, proportion, distribution, and origin of P. o. curtisi and P. o. wallikeri. It showed that imported P. ovale spp. accounts for a large proportion of total malaria cases in Henan Province, even more than that of P. vivax. This suggests that the proportion of P. ovale cases is underestimated in Africa. Among these cases, the latency period of P. o. curtisi was significantly longer than that of P. o. wallikeri. More attention should be paid to imported ovale malaria to avoid the reintroduction of these two subspecies into China.

Imported malaria in the UK, 2005 to 2016: Estimates from primary care electronic health records

OBJECTIVE

To investigate trends in the incidence of imported malaria in the UK between 2005 and 2016.

DESIGN

Analysis of longitudinal electronic health records (EHRs) in The Health Improvement Network (THIN) primary care database.

SETTING

UK primary care.

PARTICIPANTS

In total, we examined 12,349,003 individuals aged 0 to 99 years.

OUTCOME MEASURE

The rate of malaria recordings in THIN was calculated per year between 2005 and 2016. Rate ratios exploring differences by age, sex, location of general practice, socioeconomic status and ethnicity were estimated using multivariable Poisson regression.

RESULTS

A total of 1,474 individuals with a first diagnosis of malaria were identified in THIN between 2005 and 2016. The incidence of recorded malaria followed a decreasing trend dropping from a rate of 3.33 in 2005 to 1.36 cases per 100,000 person years at risk in 2016. Multivariable Poisson regression showed that adults of working age (20 to 69 years), men, those registered with a general practice in London, higher social deprivation and non-white ethnicity were associated with higher rates of malaria recordings.

CONCLUSION

There has been a decrease in the number of malaria recordings in UK primary care over the past decade. This decrease exceeds the rate of decline reported in national surveillance data; however there are similar associations with age, sex and deprivation. Improved geographic information on the distribution of cases and the potential for automation of case identification suggests that EHRs could provide a complementary role for investigating malaria trends over time.

Epidemiology of Malaria in the State of Qatar, 2008-2015

Background and Objectives

Imported malaria poses a serious public health problem in Qatar because its population is “naïve” to such infection; where local transmission might lead to serious, life-threatening infection and might even trigger epidemics.

Methods

This study is a retrospective review of the imported malaria cases in Qatar reported by the malaria surveillance program at the Ministry of Public Health (MoPH), during the period between January 2008 and December 2015. All cases were imported and underwent parasitological confirmation through microscopy.

Results

A total of 4092 malaria cases were reported during 2008–2015 in Qatar. The demographic features of the imported cases show that the majority of cases were males (93%), non-Qatari (99.6%), and aged 15 to 44 years (82.1%). Moreover, P. vivax was found to be the main etiologic agent accounting for more than three-quarters (78.7%) of the imported cases. In addition, almost a third (33.1%) of the cases were reported during the months of July, August, and September.

Conclusions

Imported malaria in Qatar has witnessed an increase during the past seven years, despite a long period of constant reduction; where the people most affected were adult male migrants from endemic countries. Many challenges need to be overcome to prevent the reintroduction of malaria into the country.

Polymorphisms analysis of the Plasmodium ovale tryptophan-rich antigen gene (potra) from imported malaria cases in Henan Province

BACKGROUND

Plasmodium ovale has two different subspecies: P. ovale curtisi and P. ovale wallikeri, which may be distinguished by the gene potra encoding P. ovale tryptophan-rich antigen. The sequence and size of potra gene was variable between the two P. ovale spp., and more fragment sizes were found compared to previous studies. Further information about the diversity of potra genes in these two P. ovale spp. will be needed.

METHODS

A total of 110 dried blood samples were collected from the clinical patients infected with P. ovale, who all returned from Africa in Henan Province in 2011-2016. The fragments of potra were amplified by nested PCR. The sizes and species of potra gene were analysed after sequencing, and the difference between the isolates were analysed with the alignment of the amino acid sequences. The phylogenetic tree was constructed by neighbour-joining to determine the genetic relationship among all the isolates. The distribution of the isolates was analysed based on the origin country.

RESULTS

Totally 67 samples infected with P. o. wallikeri, which included 8 genotypes of potra, while 43 samples infected with P. o. curtisi including 3 genotypes of potra. Combination with the previous studies, P. o. wallikeri had six sizes, 227, 245, 263, 281, 299 and 335 bp, and P. o. curtisi had four sizes, 299, 317, 335 and 353 bp, the fragment sizes of 299 and 335 bp were the overlaps between the two species. Six amino acid as one unit was firstly used to analyse the amino acid sequence of potra. Amino acid sequence alignment revealed that potra of P. o. wallikeri differed in two amino acid units, MANPIN and AITPIN, while potra of P. o. curtisi differed in amino acid units TINPIN and TITPIS. Combination with the previous studies, there were ten subtypes of potra exiting for P. o. wallikeri and four subtypes for P. o. curtisi. The phylogenetic tree showed that 11 isolates were divided into two clusters, P. o. wallikeri which was then divided into five sub-clusters, and P. o. curtisi which also formed two sub-clusters with their respective reference sequences. The genetic relationship of the P. ovale spp. mainly based on the number of the dominant amino acid repeats, the number of MANPIN, AITPIN, TINPIN or TITPIS. The genotype of the 245 bp size for P. o. wallikeri and that of the 299 and 317 bp size for P. o. curtisi were commonly exiting in Africa.

CONCLUSION

This study further proved that more fragment sizes were found, P. o. wallikeri had six sizes, P. o. curtisi had four sizes. There were ten subtypes of potra exiting for P. o. wallikeri and four subtypes for P. o. curtisi. The genetic polymorphisms of potra provided complementary information for the gene tracing of P. ovale spp. in the malaria elimination era.

Imported dengue fever in East London: a 6-year retrospective observational study

BACKGROUND

Dengue fever (DF) is a frequently imported arthropod-borne infection in the United Kingdom but its broad range of clinical presentations makes it potentially unrecognized by clinicians.

METHODS

We conducted a 6-year retrospective case note review of laboratory confirmed DF patients in East London in the period from 1 January 2010 through 31 December 2015. Epidemiological, clinical and laboratory features of imported DF were described. Risk factors associated with viraemic DF presentations were assessed.

RESULTS

Forty-four patients (4 from primary care clinics and 40 from three acute hospitals) were confirmed to have DF through RNA and/or IgM detection. In total, 86.4% (38/44) had primary infection compared to 13.6% (6/44) with secondary infection. Viraemic DF presentations accounted for 59.1% (26/44) of cases. The median age was 34 years (IQR 25-43). Most patients were males (68.2%, 30/44) and of non-white ethnicity (81.8%, 36/44). South Asia was the most frequent travel destination (52.3%, 23/44) followed by Southeast Asia (20.5%, 9/44). July-September was the peak season of presentation (43.2%, 19/44). The median interval between arrival in the UK and laboratory testing was 7 days (IQR 4-13). Arriving from abroad ≤ 7 days before molecular testing (age-adjusted odds ratios [OR] 16.98, 95% CI 2.43-118.75, P  =   0.004) and travel to South or Southeast Asia regions (age-adjusted OR 4.41, 95% CI 1.07-18.21, P  =   0.040) were associated with detectable viraemia at presentation. Only one DF patient met the WHO severity criteria. HIV serostatus was determined in 61.4% (27/44) of cases.

CONCLUSION

Clinicians need to improve DF recognition as well as rates of HIV testing in tropical travellers. Region of travel and time since arrival from DF endemic settings may help clinicians optimize requests for molecular testing. Further research on the clinical and public health aspects of imported DF is needed.

Travel During Pregnancy: Considerations for the Obstetric Provider

Importance

Travel among US citizens is becoming increasingly common, and travel during pregnancy is also speculated to be increasingly common. During pregnancy, the obstetric provider may be the first or only clinician approached with questions regarding travel.

Objective

In this review, we discuss the reasons women travel during pregnancy, medical considerations for long-haul air travel, destination-specific medical complications, and precautions for pregnant women to take both before travel and while abroad. To improve the quality of pretravel counseling for patients before or during pregnancy, we have created 2 tools: a guide for assessing the pregnant patient's risk during travel and a pretravel checklist for the obstetric provider.

Evidence Acquisition

A PubMed search for English-language publications about travel during pregnancy was performed using the search terms "travel" and "pregnancy" and was limited to those published since the year 2000. Studies on subtopics were not limited by year of publication.

Results

Eight review articles were identified. Three additional studies that analyzed data from travel clinics were found, and 2 studies reported on the frequency of international travel during pregnancy. Additional publications addressed air travel during pregnancy (10 reviews, 16 studies), high-altitude travel during pregnancy (5 reviews, 5 studies), and destination-specific illnesses in pregnant travelers.

Conclusions and Relevance

Travel during pregnancy including international travel is common. Pregnant travelers have unique travel-related and destination-specific risks. We review those risks and provide tools for obstetric providers to use in counseling pregnant travelers.

Malaria chemoprophylaxis: cross-sectional study of use among air travellers departing from Accra, Ghana

Background

Malaria is the most common life-threatening infectious disease among travellers and chemoprophylaxis is recommended. The overall effectiveness, medication types and cost of malaria chemoprophylaxis in Accra are not well documented. This study investigated the use of chemoprophylaxis for malaria prevention in air travellers departing from Kotoka International Airport (KIA) in Accra, Ghana.

Materials and methods

A cross-sectional study was conducted in the departure lounge of the KIA between February and May 2012. A total of 424 respondents voluntarily completed a semi-structured questionnaire, which included socio-demographic characteristics, duration of stay, nationality, country of permanent residence, chemoprophylaxis used, number of doses missed, cost and side effects experienced, and cost of treatment.

Results

The mean age of respondents was 37 ± 0.84 years with a male:female ratio of 1.2:1.The mean duration of stay in Ghana was 47.9 days [SD 56.8] and 73.5% had made one trip to the country in the preceding year. Of the respondents, 50.7% were from Europe, 24.1% from North America and 17.5% from Africa. The most popular malaria prevention method used was prophylactics (37%) with atovaquone/proguanil used most frequently (34.9%), followed by mefloquine (11.6%) and doxycycline (7.8%). Compliance was high: 73.8% of respondents did not miss a single dose. The most commonly reported side effects were dreams, abdominal discomfort and headaches. Malaria incidence was 7.1% with 80% of them receiving treatment in a hospital or clinic; incurring a cost of up to $30 to treat a person.

Conclusions

Most air travellers from Accr a take atovaquone/pr oguanil. Malaria incidence was low and most travellers were compliant with their chemoprophylaxis with very few side effects. The cost of chemoprophylaxis is low and is thus recommended for all travellers to Accra, Ghana.

pfk13-Independent Treatment Failure in Four Imported Cases of Plasmodium falciparum Malaria Treated with Artemether-Lumefantrine in the United Kingdom

We present case histories of four patients treated with artemether-lumefantrine for falciparum malaria in UK hospitals in 2015 to 2016. Each subsequently presented with recurrent symptoms and Plasmodium falciparum parasitemia within 6 weeks of treatment with no intervening travel to countries where malaria is endemic. Parasite isolates, all of African origin, harbored variants at some candidate resistance loci. No evidence of pfk13-mediated artemisinin resistance was found. Vigilance for signs of unsatisfactory antimalarial efficacy among imported cases of malaria is recommended.

Response to fever and utilization of standby emergency treatment (SBET) for malaria in travellers to Southeast Asia: a questionnaire-based cohort study

Background

Guidelines in several European countries recommend standby emergency treatment (SBET) for travellers to regions with low or medium malaria transmission instead of continuous chemoprophylaxis: travellers are advised to seek medical assistance within 24 h in case of fever and to self-administer SBET only if they are not able to consult a doctor within the time period specified. Data on healthcare-seeking behaviour of febrile travellers and utilization of SBET is however scarce as only two studies were performed in the mid-1990s. Since tourism is constantly increasing and malaria epidemiology has dramatically changed in the meantime more knowledge is urgently needed.

Methods

Some 876 travellers to destinations in South and Southeast Asia with low or medium malaria transmission were recruited in the travel clinic of the University Medical Center Hamburg-Eppendorf. Demographic and travel-related data were collected by using questionnaires. Pre-travel advice was carried out and SBET was prescribed in accordance to national guidelines. Post-travel phone interviews were performed to assess health incidents during travel and individual responses of travellers to febrile illness.

Results

Out of 714 patients who were monitored, 130 (18%) reported onset of fever during travel or 14 days after return. Of those travellers who reported fever, 100 (80%) carried SBET during travel. The vast majority of 79 (79%) febrile travellers who carried SBET did not seek medical assistance. Overall, 14 (14%) febrile patients who carried SBET and six (20%) patients who did not carry SBET took the correct measure (doctor visit or timely SBET administration) as a response to febrile illness, respectively. Only two travellers self-administered SBET, but both of them applied the wrong regimen.

Conclusions

In view of declining malaria transmission and improving medical infrastructure in most countries of Southeast Asia and obvious obstacles concerning SBET as shown in this study the current strategy should be re-evaluated. Pre-travel advice concerning malaria in SEA should focus on appropriate mosquito bite protection and clearly emphasize the need to see a doctor within 24 h after onset of fever.

Geographical and temporal trends in imported infections from the tropics requiring inpatient care at the Hospital for Tropical Diseases, London - a 15 year study

BACKGROUND

Understanding geographic and temporal trends in imported infections is key to the management of unwell travellers. Many tropical infections can be managed as outpatients, with admission reserved for severe cases.

METHODS

We prospectively recorded the diagnosis and travel history of patients admitted between 2000 and 2015. We describe the common tropical and non-tropical infectious diseases and how these varied based on region, reason for travel and over time.

RESULTS

A total of 4362 admissions followed an episode of travel. Falciparum malaria was the most common diagnosis (n=1089). Among individuals who travelled to Africa 1206/1724 (70.0%) had a tropical diagnosis. The risk of a tropical infection was higher among travellers visiting friends and relatives than holidaymakers (OR 2.8, p<0.001). Among travellers to Asia non-tropical infections were more common than tropical infections (349/782, 44.6%), but enteric fever (117, 33.5%) of the tropical infections and dengue (70, 20.1%) remained important. The number of patients admitted with falciparum malaria declined over the study but those of enteric fever and dengue did not.

CONCLUSIONS

Most of those arriving from sub-Saharan Africa with an illness requiring admission have a classical tropical infection, and malaria still predominates. In contrast, fewer patients who travelled to Asia have a tropical diagnosis but enteric fever and dengue remain relatively common. Those visiting friends and relatives are most likely to have a tropical infection.

Development of new malaria diagnostics: matching performance and need

Despite advances in diagnostic technology, significant gaps remain in access to malaria diagnosis. Accurate diagnosis and misdiagnosis leads to unnecessary waste of resources, poor disease management, and contributes to a cycle of poverty in low-resourced communities. Despite much effort and investment, few new technologies have reached the field in the last 30 years aside from lateral flow assays. This suggests that much diagnostic development effort has been misdirected, and/or that there are fundamental blocks to introduction of new technologies. Malaria diagnosis is a difficult market; resources are broadly donor-dependent, health systems in endemic countries are frequently weak, and the epidemiology of malaria and priorities of malaria programmes and donors are evolving. Success in diagnostic development will require a good understanding of programme gaps, and the sustainability of markets to address them. Targeting assay development to such clearly defined market requirements will improve the outcomes of product development funding. Six market segments are identified: (1) case management in low-resourced countries, (2) parasite screening for low density infections in elimination programmes, (3) surveillance for evidence of continued transmission, (4) clinical research and therapeutic efficacy monitoring, (5) cross-checking for microscopy quality control, and (6) returned traveller markets distinguished primarily by resource availability. While each of these markets is potentially compelling from a public health standpoint, size and scale are highly variable and continue to evolve. Consequently, return on investment in research and development may be limited, highlighting the need for potentially significant donor involvement or the introduction of novel business models to overcome prohibitive economics. Given the rather specific applications, a well-defined set of stakeholders will need to be on board for the successful introduction and scaling of any new technology to these markets.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

UK malaria treatment guidelines 2016

1.Malaria is the tropical disease most commonly imported into the UK, with 1300-1800 cases reported each year, and 2-11 deaths. 2. Approximately three quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. 3. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other species of plasmodium: Plasmodium ovale, Plasmodium malariae or Plasmodium knowlesi. 4. Mixed infections with more than one species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. 5. There are no typical clinical features of malaria; even fever is not invariably present. Malaria in children (and sometimes in adults) may present with misleading symptoms such as gastrointestinal features, sore throat or lower respiratory complaints. 6. A diagnosis of malaria must always be sought in a feverish or sick child or adult who has visited malaria-endemic areas. Specific country information on malaria can be found at http://travelhealthpro.org.uk/. P. falciparum infection rarely presents more than six months after exposure but presentation of other species can occur more than a year after exposure. 7. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until more than one blood specimen has been examined. Other travel related infections, especially viral haemorrhagic fevers, should also be considered. 8. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites. P. falciparum and P. vivax (depending upon the product) malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens. RDTs for other Plasmodium species are not as reliable. 9. Most patients treated for P. falciparum malaria should be admitted to hospital for at least 24 h as patients can deteriorate suddenly, especially early in the course of treatment. In specialised units seeing large numbers of patients, outpatient treatment may be considered if specific protocols for patient selection and follow up are in place. 10. Uncomplicated P. falciparum malaria should be treated with an artemisinin combination therapy (Grade 1A). Artemether-lumefantrine (Riamet(®)) is the drug of choice (Grade 2C) and dihydroartemisinin-piperaquine (Eurartesim(®)) is an alternative. Quinine or atovaquone-proguanil (Malarone(®)) can be used if an ACT is not available. Quinine is highly effective but poorly-tolerated in prolonged treatment and should be used in combination with an additional drug, usually oral doxycycline. 11. Severe falciparum malaria, or infections complicated by a relatively high parasite count (more than 2% of red blood cells parasitized) should be treated with intravenous therapy until the patient is well enough to continue with oral treatment. Severe malaria is a rare complication of P. vivax or P. knowlesi infection and also requires parenteral therapy. 12. The treatment of choice for severe or complicated malaria in adults and children is intravenous artesunate (Grade 1A). Intravenous artesunate is unlicensed in the EU but is available in many centres. The alternative is intravenous quinine, which should be started immediately if artesunate is not available (Grade 1A). Patients treated with intravenous quinine require careful monitoring for hypoglycemia. 13. Patients with severe or complicated malaria should be managed in a high-dependency or intensive care environment. They may require haemodynamic support and management of: acute respiratory distress syndrome, disseminated intravascular coagulation, acute kidney injury, seizures, and severe intercurrent infections including Gram-negative bacteraemia/septicaemia. 14. Children with severe malaria should also be treated with empirical broad spectrum antibiotics until bacterial infection can be excluded (Grade 1B). 15. Haemolysis occurs in approximately 10-15% patients following intravenous artesunate treatment. Haemoglobin concentrations should be checked approximately 14 days following treatment in those treated with IV artemisinins (Grade 2C). 16. Falciparum malaria in pregnancy is more likely to be complicated: the placenta contains high levels of parasites, stillbirth or early delivery may occur and diagnosis can be difficult if parasites are concentrated in the placenta and scanty in the blood. 17. Uncomplicated falciparum malaria in the second and third trimester of pregnancy should be treated with artemether-lumefantrine (Grade 2B). Uncomplicated falciparum malaria in the first trimester of pregnancy should usually be treated with quinine and clindamycin but specialist advice should be sought. Severe malaria in any trimester of pregnancy should be treated as for any other patient with artesunate preferred over quinine (Grade 1C). 18. Children with uncomplicated malaria should be treated with an ACT (artemether-lumefantrine or dihydroartemisinin-piperaquine) as first line treatment (Grade 1A). Quinine with doxycycline or clindamycin, or atovaquone-proguanil at appropriate doses for weight can also be used. Doxycycline should not be given to children under 12 years. 19. Either an oral ACT or chloroquine can be used for the treatment of non-falciparum malaria. An oral ACT is preferred for a mixed infection, if there is uncertainty about the infecting species, or for P. vivax infection from areas where chloroquine resistance is common (Grade 1B). 20. Dormant parasites (hypnozoites) persist in the liver after treatment of P. vivax or P. ovale infection: the only currently effective drug for eradication of hypnozoites is primaquine (1A). Primaquine is more effective at preventing relapse if taken at the same time as chloroquine (Grade 1C). 21. Primaquine should be avoided or given with caution under expert supervision in patients with Glucose-6-phosphate dehydrogenase deficiency (G6PD), in whom it may cause severe haemolysis. 22. Primaquine (for eradication of P. vivax or P. ovale hypnozoites) is contraindicated in pregnancy and when breastfeeding (until the G6PD status of child is known); after initial treatment for these infections a pregnant woman should take weekly chloroquine prophylaxis until after delivery or cessation of breastfeeding when hypnozoite eradication can be considered. 23. An acute attack of malaria does not confer protection from future attacks: individuals who have had malaria should take effective anti-mosquito precautions and chemoprophylaxis during future visits to endemic areas.

Epidemiology and clinical features of imported malaria in East London

BACKGROUND

Malaria is the most common imported tropical disease in the United Kingdom (UK). The overall mortality is low but inter-regional differences have been observed.

METHODS

We conducted a 2-year retrospective review of clinical and laboratory records of patients with malaria attending three acute hospitals in East London from 1 April 2013 through 31 March 2015. Epidemiological and clinical characteristics of imported malaria were described and risk factors associated with severe falciparum malaria were explored.

RESULTS

In total, 133 patients with laboratory-confirmed malaria were identified including three requiring critical care admission but no deaths. The median age at presentation was 41 years (IQR 30-50). The majority of patients were males (64.7%, 86/133) and had Black or Black British ethnicity (67.5%, 79/117). West Africa was the most frequent region of travel (70.4%, 76/108). Chemoprophylaxis use was poor (25.3%, 20/79). The interval between arriving in the UK and presenting to hospital was short (median 10 days; IQR 5-15.5, n = 84). July-September was the peak season of presentation (34.6%, 46/133). Plasmodium falciparum was the commonest species (76.7%, 102/133) and 31.4% (32/102) of these patients had parasitaemia >2%. Severe falciparum malaria was documented in 36.3% (37/102) of patients and the October-March season presentation was associated with an increased risk of severity (OR 3.00; 95% CI 1.30-6.93). Black patients appeared to have reduced risk of severe falciparum malaria (OR 0.46; 95% CI 0.16-1.35) but this was not statistically significant. HIV sero-status was determined in only 27.1% (36/133) of cases. Only 8.5% (10/117) of all malaria patients were treated as outpatients.

CONCLUSION

Clinicians need to raise awareness on malaria prevention strategies, improve rates of HIV testing in tropical travellers, and familiarise themselves with ambulatory management of malaria. The relationship between season of presentation, ethnicity and severity of falciparum malaria should be explored further.

Imported infections: What information should be collected by surveillance systems to inform public health policy?

Background

International travel carries the risk of imported diseases, which are an increasingly significant public health problem. There is little guidance about which variables should be collected by surveillance systems for strategy-based surveillance.

Methods

Surveillance forms for dengue, malaria, hepatitis A, typhoid and measles were collected from Australia and New Zealand and information on these compared with national surveillance forms from the UK and Canada by travel health experts. Variables were categorised by information relating to recent travel, demographics and disease severity.

Results

Travel-related information most commonly requested included country of travel, vaccination status and travel dates. In Australia, ethnicity information requested related to indigenous status, whilst in New Zealand it could be linked to census categories. Severity of disease information most frequently collected were hospitalisation and death.

Conclusions

Reviewing the usefulness of variables collected resulted in the recommendation that those included should be: overseas travel, reason for travel, entry and departure dates during the incubation period, vaccination details, traveller's and/or parents' country of birth, country of usual residence, time resident in current country, postcode, hospitalisation and death details. There was no agreement about whether ethnicity details should be collected. The inclusion of these variables on surveillance forms could enable imported infection-related policy to be formulated nationally and internationally.

The selective outpatient treatment of adults with imported falciparum malaria: a prospective cohort study

BACKGROUND

Current UK malaria treatment guidelines recommend admission for all patients diagnosed with falciparum malaria. However, evidence suggests that certain patients are at lower risk of severe malaria and death and may be managed as outpatients.

AIM

To prospectively assess the risk of post-treatment severe falciparum malaria in selected cases managed as outpatients. The readmission rate and treatment tolerability were assessed as secondary outcomes.

DESIGN

Prospective cohort study.

METHODS

Adults (>15 years old) diagnosed with falciparum malaria between May 2008 and July 2012 were selected for outpatient treatment using locally defined clinical and laboratory indicators based on known risk factors for severity and death. Treatment outcomes were assessed in clinic or by telephone 4-6 weeks after treatment.

RESULTS

269 adults were diagnosed with falciparum malaria on blood film between May 2008 and July 2012. Of 255 eligible participants, 106 patients were offered ambulatory treatment, of which 95 completed the study. The severe malaria rate was 0% (95% confidence interval (CI) 0-3.8%) and the readmission rate was 5.3% (95% CI 1.7-11.9) in the outpatient group. In addition, 10.6% (95% CI 5.2-18.7%) of outpatients reported drug-related side effects.

CONCLUSIONS

The outpatient treatment of selected cases of falciparum malaria is effective in our high volume UK setting. We recommend adopting a similar approach to managing this infection in other non-endemic settings where immediate access to specialist advice is available.

Malaria in the returning older traveler

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Trends of imported malaria in China 2010-2014: analysis of surveillance data

Background

To describe the epidemiologic profile and trends of imported malaria, and to identify the populations at risk of malaria in China during 2010–2014.

Methods

This is a descriptive analysis of laboratory confirmed malaria cases during 2010–2014. Data were obtained from surveillance reports in the China Information System for Disease Control and Prevention (CISDCP). The distribution of imported malaria cases over the years was analysed with X² for trend analysis test. All important demographic and epidemiologic variables of imported malaria cases were analysed.

Results

Malaria incidence in general reduced greatly in China, while the proportion of Plasmodium falciparum increased threefold from 0.08 to 0.21 per 100,000 population during the period 2010–2014. Of a total 17,725 malaria cases reported during the study period, 11,331 (64 %) were imported malaria and included an increasing trend: 292 (6 %), 2103 (63 %), 2151 (84 %), 3881 (96 %), 2904 (97 %), respectively, (X² = 2110.70, p < 0.01). The majority of malaria cases (imported and autochthonous) were adult (16,540, 93 %), male (15,643, 88 %), and farming as an occupation (11,808, 66 %). Some 3027 (94 %) of imported malaria cases had labour-related travel history during the study period; 90 % (6340/7034) of P. falciparum infections were imported into China from Africa, while 77 % of Plasmodium vivax infections (2440/3183) originated from Asia.

Conclusions

Malaria elimination in China faces the challenge of imported malaria, especially imported P. falciparum. Malaria prevention activities should target exported labour groups given the increasing number of workers returning from overseas.

Delayed Onset of Symptoms and Atovaquone-Proguanil Chemoprophylaxis Breakthrough by Plasmodium malariae in the Absence of Mutation at Codon 268 of pmcytb

Plasmodium malariae is widely distributed across the tropics, causing symptomatic malaria in humans with a 72-hour fever periodicity, and may present after latency periods lasting up to many decades. Delayed occurrence of symptoms is observed in humans using chemoprophylaxis, or patients having received therapies targeting P. falciparum intraerythrocytic asexual stages, but few investigators have addressed the biological basis of the ability of P. malariae to persist in the human host. To investigate these interesting features of P. malariae epidemiology, we assembled, here, an extensive case series of P. malariae malaria patients presenting in non-endemic China, Sweden, and the UK who returned from travel in endemic countries, mainly in Africa. Out of 378 evaluable P. malariae cases, 100 (26.2%) reported using at least partial chemoprophylaxis, resembling the pattern seen with the relapsing parasites P. ovale spp. and P. vivax. In contrast, for only 7.5% of imported UK cases of non-relapsing P. falciparum was any chemoprophylaxis use reported. Genotyping of parasites from six patients reporting use of atovaquone-proguanil chemoprophylaxis did not reveal mutations at codon 268 of the cytb locus of the P. malariae mitochondrial genome. While travellers with P. malariae malaria are significantly more likely to report prophylaxis use during endemic country travel than are those with P. falciparum infections, atovaquone-proguanil prophylaxis breakthrough was not associated with pmcytb mutations. These preliminary studies, together with consistent observations of the remarkable longevity of P. malariae, lead us to propose re-examination of the dogma that this species is not a relapsing parasite. Further studies are needed to investigate our favoured hypothesis, namely that P. malariae can initiate a latent hypnozoite developmental programme in the human hepatocyte: if validated this will explain the consistent observations of remarkable longevity of parasitism, even in the presence of antimalarial prophylaxis or treatment.

Imported malaria including HIV and pregnant woman risk groups: overview of the case of a Spanish city 2004-2014

BACKGROUND

Arrival of inmigrants from malaria endemic areas has led to a emergence of cases of this parasitic disease in Spain. The objective of this study was to analyse the high incidence rate of imported malaria in Fuenlabrada, a city in the south of Madrid, together with the frequent the lack of chemoprophylaxis, for the period between 2004 and 2014. Both pregnant women and HIV risk groups have been considered.

METHODS

Retrospective descriptive study of laboratory-confirmed malaria at the Fuenlabrada University Hospital, in Madrid, during a 10-year period (2004-2014). These data were obtained reviewing medical histories of the cases. Relevant epidemiological, clinical and laboratory results were analysed, with focus on the following risk groups: pregnant women and individuals with HIV.

RESULTS

A total of 185 cases were diagnosed (90.3 % Plasmodium falciparum). The annual incidence rate was 11.9/100,000 inhabitants/year. The average age was 30.8 years (SD: 14.3). Infections originating in sub-Saharan Africa comprised the 97.6 % of the cases. A total of 85.9 % were Visiting Friends and Relatives. Only a 4.3 % completed adequate prophylaxis. A total of 14.28 % of the fertile women were pregnant, and 8 cases (4.3 %) had HIV. None of them in these special groups completed prophylaxis.

CONCLUSIONS

The incidence rate in Fuenlabrada is higher than in the rest of Spain, due to the large number of immigrants from endemic areas living in the municipality. However, the results are not representative of all the country. It seems to be reasonable to implement prevention and pre-travel assessment programs to increase chemoprophylaxis. Pregnancy tests and HIV serology should be completed for all patients to improve prophylactic methods.

Imported malaria in pregnant women: A retrospective pooled analysis

BACKGROUND

Data on imported malaria in pregnant women are scarce.

METHOD

A retrospective, descriptive study of pooled data on imported malaria in pregnancy was done using data from 1991 to 2014 from 8 different collaborators in Europe, the United States and Japan. National malaria reference centres as well as specialists on this topic were asked to search their archives for cases of imported malaria in pregnancy. A total of 631 cases were collated, providing information on Plasmodium species, region of acquisition, nationality, country of residence, reason for travel, age, gestational age, prophylactic measures and treatment used, as well as on complications and outcomes in mother and child.

RESULTS

Datasets from some sources were incomplete. The predominant Plasmodium species was P. falciparum (78.5% of cases). Among the 542 cases where information on the use of chemoprophylaxis was known, 464 (85.6%) did not use chemoprophylaxis. The main reason for travelling was "visiting friends and relatives" VFR (57.8%) and overall, most cases of malaria were imported from West Africa (57.4%). Severe anaemia was the most frequent complication in the mother. Data on offspring outcome were limited, but spontaneous abortion was a frequently reported foetal outcome (n = 14). A total of 50 different variants of malaria treatment regimens were reported.

CONCLUSIONS

Imported cases of malaria in pregnancy are mainly P. falciparum acquired in sub-Saharan Africa. Malaria prevention and treatment in pregnant travellers is a challenge for travel medicine due to few data on medication safety and maternal and foetal outcomes. International, collaborative efforts are needed to capture standardized data on imported malaria cases in pregnant women.

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.

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

Background

The proportion of all imported malaria reported in travellers visiting friends and relatives (VFRs) in the UK has increased over the past decade and the proportion of Plasmodium falciparum malaria affecting this group has remained above 80% during that period. The epidemiological data suggest that the strategies employed in the UK to prevent imported malaria have been ineffective for VFRs. This paper attempts to identify possible reasons for the failure of the malaria prevention strategy among VFRs and suggest potential alternatives.

Methods

A review of the current UK malaria prevention guidelines was undertaken and their approach was compared to the few data that are available on malaria perceptions and practices among VFRs.

Results

The current UK malaria prevention guidelines focus on educating travellers and health professionals using messages based on the personal threat of malaria and promoting the benefits of avoiding disease through the use of chemoprophylaxis. While malaria morbidity disproportionately affects VFRs, the mortality rates from malaria in VFRs is eight times, and severe disease eight times lower than in tourist and business travellers. Recent research into VFR malaria perceptions and practices has highlighted the complex socio-ecological context within which VFRs make their decisions about malaria. These data suggest that alternative strategies that move beyond a knowledge-deficit approach are required to address the burden of malaria in VFRs.

Discussion

Potential alternative strategies include the use of standby emergency-treatment (SBET) for the management of fevers with an anti-malarial provided pre-travel, the provision of rapid diagnostic testing and treatment regimen based in general-practitioner surgeries, and urgent and walk-in care centres and local accident and emergency (A&E) departments to provide immediate diagnosis and accessible ambulatory treatment for malaria patients. This latter approach would potentially address some of the practical barriers to reducing the burden of malaria in VFRs by moving the process nearer to the community.

Climate drivers on malaria transmission in Arunachal Pradesh, India

The present study was conducted during the years 2006 to 2012 and provides information on prevalence of malaria and its regulation with effect to various climatic factors in East Siang district of Arunachal Pradesh, India. Correlation analysis, Principal Component Analysis and Hotelling's T² statistics models are adopted to understand the effect of weather variables on malaria transmission. The epidemiological study shows that the prevalence of malaria is mostly caused by the parasite Plasmodium vivax followed by Plasmodium falciparum. It is noted that, the intensity of malaria cases declined gradually from the year 2006 to 2012. The transmission of malaria observed was more during the rainy season, as compared to summer and winter seasons. Further, the data analysis study with Principal Component Analysis and Hotelling's T² statistic has revealed that the climatic variables such as temperature and rainfall are the most influencing factors for the high rate of malaria transmission in East Siang district of Arunachal Pradesh.

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

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

The clinical and public health problem of relapse despite primaquine therapy: case review of repeated relapses of Plasmodium vivax acquired in Papua New Guinea

BACKGROUND

Primaquine is the only drug available for preventing relapse following a primary attack by Plasmodium vivax malaria. This drug imposes several important problems: daily dosing over two weeks; toxicity in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency; partner blood schizontocides possibly impacting primaquine safety and efficacy; cytochrome P-450 abnormalities impairing metabolism and therapeutic activity; and some strains of parasite may be tolerant or resistant to primaquine. There are many possible causes of repeated relapses in a patient treated with primaquine.

CASE DESCRIPTION

A 56-year-old Caucasian woman from New Zealand traveled to New Ireland, Papua New Guinea for two months in 2012. One month after returning home she stopped daily doxycycline prophylaxis against malaria, and one week later she became acutely ill and hospitalized with a diagnosis of Plasmodium vivax malaria. Over the ensuing year she suffered four more attacks of vivax malaria at approximately two-months intervals despite consuming primaquine daily for 14 days after each of those attacks, except the last. Genotype of the patient's cytochrome P-450 2D6 alleles (*5/*41) corresponded with an intermediate metabolizer phenotype of predicted low activity.

DISCUSSION

Multiple relapses in patients taking primaquine as prescribed present a serious clinical problem, and understanding the basis of repeated therapeutic failure is a challenging technical problem. This case highlights these issues in a single traveler, but these problems will also arise as endemic nations approach elimination of malaria transmission.

Risk factors for UK Plasmodium falciparum cases

BACKGROUND

An increasing proportion of malaria cases diagnosed in UK residents with a history of travel to malaria endemic areas are due to Plasmodium falciparum.

METHODS

In order to identify travellers at most risk of acquiring malaria a proportional hazards model was used to estimate the risk of acquiring malaria stratified by purpose of travel and age whilst adjusting for entomological inoculation rate (EIR) and duration of stay in endemic countries.

RESULTS

Travellers visiting friends and relatives and business travellers were found to have significantly higher hazard of acquiring malaria (adjusted hazard ratio (HR) relative to that of holiday makers 7.4, 95% CI 6.4-8.5, p < 0. 0001 and HR 3.4, 95% CI 2.9-3.8, p < 0. 0001, respectively). All age-groups were at lower risk than children aged 0-15 years.

CONCLUSIONS

These estimates of the increased risk for business travellers and those visiting friends and relatives should be used to inform programmes to improve awareness of the risks of malaria when travelling.

Imported malaria in a non-endemic area: the experience of the university of Campinas hospital in the Brazilian Southeast

BACKGROUND

Although malaria in Brazil almost exclusively occurs within the boundaries of the Amazon Region, some concerns are raised regarding imported malaria to non-endemic areas of the country, notably increased incidence of complications due to delayed diagnoses. However, although imported malaria in Brazil represents a major health problem, only a few studies have addressed this subject.

METHODS

A retrospective case series is presented in which 263 medical charts were analysed to investigate the clinical and epidemiological characterization of malaria cases that were diagnosed and treated at Hospital & Clinics, State University of Campinas between 1998 and 2011.

RESULTS

Amongst all medical charts analysed, 224 patients had a parasitological confirmed diagnosis of malaria. Plasmodium vivax and Plasmodium falciparum were responsible for 67% and 30% of the infections, respectively. The majority of patients were male (83%) of a productive age (median, 37 years old). Importantly, severe complications did not differ significantly between P. vivax (14 cases, 9%) and P. falciparum (7 cases, 10%) infections.

CONCLUSIONS

Severe malaria cases were frequent among imported cases in Brazil outside of the Amazon area. The findings reinforce the idea that P. vivax infections in Brazil are not benign, regardless the endemicity of the area studied. Moreover, as the hospital is located in a privileged site, it could be used for future studies of malaria relapses and primaquine resistance mechanisms. Finally, based on the volume of cases treated and the secondary complications, referral malaria services are needed in the non-endemic areas of Brazil for a rapid and efficient and treatment.

Managing malaria in the intensive care unit

The number of people travelling to malaria-endemic countries continues to increase, and malaria remains the commonest cause of serious imported infection in non-endemic areas. Severe malaria, mostly caused by Plasmodium falciparum, often requires intensive care unit (ICU) admission and can be complicated by cerebral malaria, respiratory distress, acute kidney injury, bleeding complications, and co-infection. The mortality from imported malaria remains significant. This article reviews the manifestations, complications and principles of management of severe malaria as relevant to critical care clinicians, incorporating recent studies of anti-malarial and adjunctive treatment. Effective management of severe malaria includes prompt diagnosis and early institution of effective anti-malarial therapy, recognition of complications, and appropriate supportive management in an ICU. All cases should be discussed with a specialist unit and transfer of the patient considered.

The epidemiology of imported malaria in Taiwan between 2002-2013: the importance of sensitive surveillance and implications for pre-travel medical advice

The purpose of this study was to assess the epidemiology of imported malaria in Taiwan between 2002 and 2013. We analyzed the national data recorded by the Taiwan Centers for Disease Control (Taiwan CDC). Malaria cases were diagnosed by blood films, polymerase chain reaction, or rapid diagnostic tests. The risk of re-establishment of malarial transmission in Taiwan was assessed. A total of 229 malaria cases were included in our analysis. All of the cases were imported. One hundred and ninety-two cases (84%) were diagnosed within 13 days of the start of symptoms/signs; 43% of these cases were acquired in Africa and 44% were acquired in Asia. Plasmodium falciparum was responsible for the majority (56%) of these cases. Travel to an endemic area was associated with the acquisition of malaria. The malaria importation rate was 2.36 per 1,000,000 travelers (range 1.20–5.74). The reproductive number under control (R_c) was 0. No endemic transmission of malaria in Taiwan was identified. This study suggests that a vigilant surveillance system, vector-control efforts, case management, and an educational approach focused on travelers and immigrants who visit malaria endemic countries are needed to prevent outbreaks and sustain the elimination of malaria in Taiwan.

Assessment of returning travellers with fever

Millions of people travel to the tropics each year and a significant minority of them become ill, either during their stay, or shortly after their return. Most have mild, self-limiting illnesses, but a few will have a life-threatening condition. This article outlines how to evaluate fever in the returning traveller and discusses important infection control and public health measures. A detailed travel history, which takes into account travel destinations, specific activities and risk factors in relation to the onset of symptoms, is essential for constructing a comprehensive list of differential diagnoses and guiding appropriate investigations. Importantly, all travellers returning from the tropics with a fever should be investigated for malaria, even if their return was 3 months ago or longer.