Malaria at Christmas: risks of prophylaxis versus risks of malaria

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.

[Mood disorder after malaria prophylaxis with mefloquine (two case reports)]

INTRODUCTION

Mefloquine (Lariam) is the drug of choice as malaria prophylaxis for travel to chloroquine-resistant areas. Severe neuropsychiatric side effects are rare. We report two clinical cases of mood disorders: mania and a major depressive episode with psychotic characteristics in two patients with mefloquine antimalarial prophylaxis. FIRST CLINICAL CASE: A 31-year-old man had taken mefloquine at a rate of 250mg/week as malaria prophylaxis for his mission in Democratic Republic of Congo. He developed mania with psychotic symptoms after taking five tablets of 250mg of mefloquine. He exhibited an elevated mood and also developed delusions of grandeur, reference and persecution, with auditory hallucinations. The physical examination and the blood laboratory tests were normal. The patient was treated with an atypical neuroleptic (olanzapine 20mg/d) leading to a complete resolution of symptomatology at the end of 3 weeks. SECOND CLINICAL CASE: A 27-year-old man presented a major depressive episode with psychotic symptoms after 1 week on his return from a stay in Democratic Republic of Congo, where he had taken mefloquine during 6 months as malaria prophylaxis (250mg/week). His physical examination and investigations (full blood test, serology and MRN) were normal. The patient was treated with clomipramine (150mg/d) and olanzapine (20mg/d). The outcome was favorable after 4 weeks.

DISCUSSION

Mefloquine is widely accepted as a safe and effective treatment and a prophylactic agent for chlorquine-resistant malaria. Common neuropsychiatric adverse effects of mefloquine can occur in up to 40% of patients, such as dizziness, sleep disturbances, anorexia, ataxia, and fatigue. Other more serious adverse reactions are rare. They are represented primarily by panic attacks, convulsions, acute psychosis, paranoid delusions, suicidal ideation, disorders of mood: major depressive episode and the manic excitation. The incidence of such neuropsychiatric effects is 1/10,000 to 1/15,000 during the prophylactic treatment. The causal mechanism for the side effects is not known. Several risk factors increasing the neurotoxicity of mefloquine can be identified, the patient with personal or family history of psychiatric disorders are more frequently concerned. Alcohol and the association with other drugs (like quinine) are two other risk factors.

CONCLUSION

It is relevant for medical practitioners to be aware of the severe neuropsychiatric side effects of mefloquine as malaria prophylaxis. It requires investigation of the risk factors such as personal or family history of psychiatric disorders.

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

OBJECTIVE

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

SETTING

National malaria reference laboratory surveillance data in the UK.

DESIGN

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

PARTICIPANTS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Imported malaria in a cosmopolitan European city: a mirror image of the world epidemiological situation

Background

International travel and migration have been related with an increase of imported malaria cases. There has been considerable immigration to Barcelona from low-income countries (LIC) in recent years. The objective is to describe the epidemiology and to determine the trends of the disease in Barcelona.

Methods

Analysis of the cases notified among city residents between 1989 and 2005. Patients were classified as: tourists, voluntary workers, resident immigrants (visiting friends and relatives, VFR) and recently arrived immigrants. An analysis was conducted using the chi² test and comparison of means. As a measure of association we calculated the Relative Risk (RR) and Odds Ratio (OR) with a Confidence Interval of 95% (CI) and carried out a trends analysis.

Results

Of the total of 1,579 imported cases notified, 997 (63.1%) lived in Barcelona city, and 55.1% were male. The mean age of patients was 32.7 years. The incidence increased from 2.4 cases/100,000 in 1989 to 3.5 cases/100,000 in 2005 (RR 1.46 CI:1.36–1.55). This increase was not statistically significant (trends analysis, p = 0.36). In terms of reason for travelling, 40.7% were VFR, 33.6% tourists, 12.1% voluntary workers and 13.6% were recently arrived immigrants. The most frequent species found was Plasmodium falciparum (71.3%), mainly in visitors to Africa (OR = 2.3, CI = 1.7–3.2). The vast majority (82.2%) had had some contact with Africa (35.9% with Equatorial Guinea, a Spanish ex-colony) and 96.6% had not completed chemoprophylaxis. Six deaths were observed, all tourists who had travelled to Africa and not taken chemoprophylaxis (3.9% fatality rate).

Conclusion

Over the period studied there is an increase in malaria incidence, however the trend is not statistically significant. Lack of chemoprophylaxis compliance and the association between Africa and P. falciparum are very clear in the imported cases. Most of the patients with malaria did not take chemoprophylaxis.

Problem pathogens: prevention of malaria in travellers

Human infection with Plasmodium spp leading to clinical episodes of malaria probably began very early in the history of humankind and has persistently inflicted disease among human populations. Malaria is currently considered the world's most important parasitic infection. The global impact of malaria is incalculable and appears to be worsening over the past decades. Although most of this burden of disease is carried by developing tropical countries, cases of imported malaria acquired by international travel are increasingly reported. These numbers are growing because of increased travel to malaria-endemic areas and also due to increased risk of transmission in these areas. Indeed, travel has contributed to the global spread of malaria during the history of humankind. Travellers visiting malaria risk areas should use both personal protective measures and chemoprophylaxis. Non-adherence to chemoprophylactic regimens is frequently secondary to drug side-effects. Therefore, a careful risk-benefit analysis on the use of antimalarial prophylaxis should be carried out in every individual travelling to malaria risk areas. Standby malaria self-treatment represents an alternative in some travellers. However, carefully selected and geographically specific antimalarial drug regimens should be recommended to non-immune people travelling to high-risk areas.

Do travelers really take their mefloquine malaria chemoprophylaxis? Estimation of adherence by an electronic pillbox

BACKGROUND

Nonadherence to chemoprophylaxis could explain why some travelers get malaria. Adherence is notoriously difficult to assess, and most studies have been conducted using questionnaires. This study aims at assessing continuous adherence more accurately with the help of an electronic pillbox.

METHODS

Adult travelers to sub-Saharan Africa had to fill a questionnaire on demographic and travel data, drug intake, and adverse events. They received oral and written information about malaria and mefloquine prophylaxis and a Medication Event Monitoring System (MEMS, Aardex, Zug, Switzerland), ie, a bottle closed with a cap containing a microprocessor recording date and time of all openings, filled with the exact number of mefloquine 250 mg tablets (Lariam, Roche Reinach, Switzerland). The MEMS) was returned with the questionnaire after completion of chemoprophylaxis.

RESULTS

According to the MEMS, only 26 of 81 travelers (32.1%) took all the doses at the expected date, another 8 (9.9%) did so but starting late with the first dose, and 19 others (23.5%) took all the pills but with intervals of +/-1 day from the right date. Another eight (9.9%) took all the pills but in a random way. The remaining 20 travelers (24.7%) missed some doses, mainly after return. Strict adherence as assessed by electronic monitoring was therefore lower than adherence measured by questionnaire (32.1% vs 48% in taking all the tablets on the right day). There was no difference between the two methods when a broader definition of adherence was applied [taking all the tablets on the right day (+/-1 day); 53/81 (65.4%)], but the MEMS showed that some answers to the questionnaire were not reliable.

CONCLUSION

The use of electronic pillboxes confirms the low adherence of travelers to mefloquine chemoprophylaxis in spite of extensive information about the disease and its prevention. Electronic assessment of pill taking, for the first time applied to malaria chemoprophylaxis, gives new insights into the real adherence of travelers.

Malaria Primer for Clinicians in the United States

Though low, the incidence of malaria in the United States is not insignificant and can be the source of infection in febrile travelers returning from endemic areas. Clinicians practicing in the United States must have a basic understanding of the malaria life cycle and its treatments to properly diagnose and treat this potentially fatal disease. Malaria chemotherapy can be broken into clinical classes for easier understanding, and any traveler to a malaria-endemic region should be placed on prophylactic medications. Mosquito bite prevention should be undertaken by all travelers, and methods of deterring mosquito bites should be understood.

Atovaquone-proguanil versus mefloquine for malaria prophylaxis in nonimmune travelers: results from a randomized, double-blind study

Concerns about the tolerability of mefloquine highlight the need for new drugs to prevent malaria. Atovaquone-proguanil (Malarone; GlaxoSmithKline) was safe and effective for prevention of falciparum malaria in lifelong residents of malaria-endemic countries, but experience in nonimmune people is limited. In a randomized, double-blind study, nonimmune travelers received malaria prophylaxis with atovaquone-proguanil (493 subjects) or mefloquine (483 subjects). Information about adverse events (AEs) and potential episodes of malaria was obtained 7, 28, and 60 days after travel. AEs were reported by an equivalent proportion of subjects who had received atovaquone-proguanil or mefloquine (71.4% versus 67.3%; difference, 4.1%; 95% confidence interval, -1.71 to 9.9). Subjects who received atovaquone-proguanil had fewer treatment-related neuropsychiatric AEs (14% versus 29%; P=.001), fewer AEs of moderate or severe intensity (10% versus 19%; P=.001), and fewer AEs that caused prophylaxis to be discontinued (1.2% versus 5.0%; P=.001), compared with subjects who received melfoquine. No confirmed diagnoses of malaria occurred in either group. Atovaquone-proguanil was better tolerated than was mefloquine, and it was similarly effective for malaria prophylaxis in nonimmune travelers.

Malaria chemoprophylaxis in the age of drug resistance. II. Drugs that may be available in the future

All current regimens of malaria chemoprophylaxis have serious drawbacks as a result of either suboptimal efficacy, difficulty with medication compliance, or adverse events. Two 8-aminoquinolines may be approaching registration, with primaquine having completed its prophylactic field testing and tafenoquine having begun advanced field testing at the end of 2000. Primaquine has long been used for management of relapses of malaria, but in the past decade, it has been reexamined for use in malaria prevention in order to stop infection in the liver. In field trials performed in Indonesia and Colombia, the efficacy of primaquine for malaria prevention was approximately 90%, compared with that of placebo. Because of its short half-life, primaquine requires daily administration. For adults, the prevention regimen is 30 mg base daily (0.5 mg base/kg/day), and it can probably be discontinued soon after departure from an area where malaria is endemic. To kill parasites that already exist in the liver, terminal prophylaxis is given after exposure to relapses of malaria infection; for adults, such prophylaxis usually consists of 15 mg base (0.3 mg base/kg/day) given daily for 2 weeks. Primaquine-induced gastrointestinal disturbances can be minimized if the drug is taken with food. Neither primaquine nor tafenoquine should be given to persons with glucose-6-phosphate dehydrogenase deficiency, to avoid the development of potentially severe drug-induced hemolysis. Tafenoquine is an analogue of primaquine that is more potent than the parent drug. Field trials in Kenya, Ghana, Gabon, and Southeast Asia have demonstrated an efficacy rate of approximately 90% for tafenoquine. Its long half-life allows for infrequent dosing (currently tested at 200 mg base/week), and its effect on parasites at the liver stage may allow for drug discontinuation at the time of departure from the area of endemicity.

Malaria chemoprophylaxis in the age of drug resistance. I. Currently recommended drug regimens

As international travel becomes increasingly common and resistance to antimalarial drugs escalates, a growing number of travelers are at risk for contracting malaria. Parasite resistance to chloroquine and proguanil and real or perceived intolerance among patients to standard prophylactic agents such as mefloquine have highlighted the need for new antimalarial drugs. Promising new regimens include atovaquone and proguanil, in combination; primaquine; and a related 8-aminoquinoline, tafenoquine. These agents are active against the liver stage of the malaria parasite and therefore can be discontinued shortly after the traveler leaves an area where malaria is endemic, which encourages adherence to the treatment regimen. Part 1 of this series reviews currently recommended chemoprophylactic drug regimens, and part 2 will focus on 8-aminoquinoline drugs.

Malaria chemoprophylaxis in UK general practitioners traveling to South Asia

BACKGROUND

Imported malaria continues to be a significant cause of morbidity and mortality in the United Kingdom. Low uptake and poor compliance of chemoprophylaxis are thought to be contributory factors. Little information is available on how well health care physicians comply with malaria chemoprophylaxis when they travel to malarial areas. The aim of this study was to determine the usage and compliance of malarial chemoprophylaxis by general practitioners who have traveled to South Asia.

METHOD

A telephone survey of 172 general practitioners practicing in the West Yorkshire area of the UK who have traveled to South Asia.

RESULTS

Of the 145 (84%) responding to the survey, 50 (35%) took no chemoprophylaxis, 28 (19%) did not complete the chemoprophylaxis course, and 67 (46%) were fully compliant. The reasons for noncompliance were; the belief the area visited was free from malaria (34%), no wish to take prophylaxis (18%), previous side-effects (10%), the belief of possessing long-term immunity (10%), no time to obtain prophylaxis (4%), malaria is easier to treat than to prevent (2%), costs of purchasing prophylaxis (2%), went for a short period of time and took the risk (2%), and no specific reason (18%).

CONCLUSIONS

This study has shown that a large proportion of general practitioners questioned did not take the recommended antimalarial prophylaxis. If they themselves do not keep to the guidelines, it is of concern that they may not reinforce the taking of chemoprophylaxis by their patients. Training in travel medicine may improve chemoprophylaxis uptake by general practitioners, but until then, such physicians should not be regarded as the main provider of pretravel advice. All travelers including health care physicians should be aware, and should comply with malarial prophylaxis guidelines, with emphasis on chemoprophylaxis compliance and mosquito avoidance.

Malaria deaths in visitors to Canada and in Canadian travellers: a case series

Over the last decade there has been a marked increase in case of drug-resistant and severe malaria in Canadian travellers. We report 7 deaths due to falciparum malaria that occurred in Canada or in Canadian travellers. Risks for malaria infection include inappropriate recommendations for malaria prevention by health care providers and lack of knowledge about or adherence to appropriate recommendations by the travelling public. Risks for death include delays in seeking medical attention, delays in diagnosis and inadequate care by Canadian physicians and hospitals, and lack of access to parenteral therapy for severe malaria. Malaria infections and deaths are preventable. Better education of health care providers and travellers about the risks of malaria and appropriate prevention and treatment measures may decrease this unnecessary burden on the Canadian health care system.

How important a priority is travel medicine for a typical British family practice?

BACKGROUND

Primary care teams have to supply travel health advice to increasing numbers of long haul travelers but there is a shortage of information derived from general practice settings about the risks patients are exposed to. We aimed to determine the numbers of our patients visiting high-risk destinations, to see if they reported complying with health advice, and whether or not they became ill.

METHODS

We performed a retrospective study in a typical British, town center, family practice in Mansfield, Nottinghamshire. A postal questionnaire survey was sent to 200 adults, aged between 16 and 76, randomly selected from the practice register, and 351 adults who had attended the practice travel clinic over a 1-year period between 1997-1998.

RESULTS

Responses were received from 84% of the random sample and 86% of the travel clinic group. Out of 11,000 patients registered with the practice, we identified 187 patients who had traveled to high-risk destinations such as Africa, Asia, South America or the Caribbean. The majority of these had attended the practice travel clinic. Despite this, 41% became ill (mainly diarrhea), 10% were sufficiently ill to be confined to bed. Fifty-nine percent of patients who required malaria chemoprophylaxis reported they had not complied fully with advice given. Reported illness rates for medium and low risk destinations were 27 and 19% respectively.

CONCLUSIONS

The results suggest that giving health advice to long haul travelers should be an important priority for primary care teams. Travelers have a high episode rate of illness and put themselves at risk of acquiring malaria. Most travelers to high-risk destinations do attend the travel clinic for health advice but compliance with that advice is poor. People traveling to lower risk destinations still experience an appreciable rate of illness and are less likely to be seen in the travel clinic.

Prevention and treatment of malaria in UK travellers

With around 2500 new cases of malaria being reported each year and more than a million UK residents visiting malaria endemic countries, there has never been a greater need for effective prevention and treatment. The latest information on malaria management is outlined below.

New therapies and changing patterns of treatment for malaria

The launch of the Roll Back Malaria initiative by the World Health Organization in the period under review confirms malaria's place as one of the great public health priorities worldwide. The period 1998-1999 has seen some advances and some disappointments in the treatment of malaria, against a backdrop of spreading drug resistance. Most encouraging is the clear demonstration that intermittent prospective treatment of asymptomatic pregnant women in endemic areas reduces morbidity. The greatest disappointment has been the result of trials with the artemether-benflumetol fixed-dose combination therapy. Questions have been raised about several widely accepted practices, including measurement of quinine levels, exchange transfusion, and the prophylactic use of anticonvulsants in children with cerebral malaria.