Malaria in Britain: 1977-86

Benefit incidence analysis of free insecticide treated nets distribution in urban and rural communities of Enugu state, South East Nigeria

BACKGROUND

Malaria is a leading cause of mortality as well as a barrier to economic and social development in developing countries. The use of insecticide-treated nets (ITNs) for malaria vector control is effective in controlling malaria attacks in pregnant women and under-5 children. The Nigerian government, in its bid to achieve the Millennium Development Goal (MDG) 4 and 5 distributes free ITNs to pregnant mothers and under-five children in the Roll Back Malaria programme (RBM).

AIM

This study compared the benefit incidence analysis of this government program between urban and rural areas.

MATERIALS AND METHODS

Pretested, semi-structured questionnaires were administered to 150 pregnant women and also 150 mothers of under-5 children, who were randomly selected from each of the two communities (rural and urban) from a local government area (LGA) in Enugu state, Nigeria. The study was conducted within the rainy season periods (March-August) of 2008. The information obtained included some socio-economic variables, accessibility, usage and benefits of usage of ITNs. Data entry and analyses were done using the Statistical Package for Social Sciences (SPSS) version 15.0(Chicago IL, USA). Student's t-test and Chi-square were used for comparison where appropriate. Significant values were taken as P value. Value of less than 0.05 was considered significant.

RESULTS

The respondents' mean monthly expenditures on food utilities and anti-malarials in the rural area and urban areas were N266.1 (74.02), range (143.3-395) and N473 (90) range (380-495.7) respectively (P < 0.001). Within each socio-economic stratum (SES), the average monthly expenditure in the urban community was higher than that of the rural community except for least poor SES (P < 0.05). For the urban community, 106 (71.6%) respondents used ITNs as against 99 (66.9%) in the rural community [P = 0.778, OR = 1.3 (95% CI: 0.76, 2.05)]. Also, ITNs were always accessible to 112 (75.7%) and 54 (36.5%) respondents in the urban and rural communities respectively [P < 0.001, OR = 5.4 (95% CI: 3.28, 8.96)]. In the urban community, 130 (87.7%) respondents expressed some benefit from ITNs as against 123 (83.1%) respondents from the rural community [P = 0.258, OR = 1.5 (95% CI: 0.76, 2.28)].

CONCLUSION

Most pregnant women and mothers of under-five children in the rural study area belong to the poorest socio-economic classes and they spend less on anti-malarial treatment. Majority of the free ITN's beneficiaries in both urban and rural study areas have used and benefitted from them.

Artemisinin based combination therapy in travel medicine

A steadily increasing number of Western travellers are exposed to malaria. Also, numbers of migrants from malarious areas are increasing. Fast and effective treatment options are needed to ensure effective malaria treatment in these groups in the future. Artemisinin combinations are well tolerated and have shown high efficacy in malaria endemic areas. Since 2001, 42 malaria endemic countries, 23 of them in Africa, have adopted artemisinin based combination therapies recommended by WHO. An additional 14 countries are in the process of changing their malaria treatment policy. Studies in non-immune travellers confirm a rapid parasite clearance time and very low rate of side effects. Outpatient clinics and hospitals in non-endemic countries should have standard operating procedures for diagnosing and managing patients with malaria. In this setting, artemisinin combinations should be available for treatment of uncomplicated malaria as they are clearly superior to any other oral antimalarial in their fast reduction of parasite biomass and in decreasing clinical symptoms. Also, they are the drugs of choice for travellers who are advised to carry stand-by emergency treatment during their journey.

Sudden death caused by parasites: postmortem cerebral malaria discoveries in the african endemic zone

This survey presents several cases of sudden deaths in Africa, specifically in Cote d'Ivoire, where the postmortem diagnosis of human cerebral malaria was determined after autopsy followed by pathologic examination of the brain. It is thought that cerebral malaria may be the primary cause of sudden death in nonimmunized persons during or after traveling in such endemic areas of Africa. The target population is composed of tourists, business travelers, and sailors. Because death caused by cerebral malaria occurs so suddenly, it can lead to forensic issues. Therefore, in any cases involving sudden death, it is very important for the forensic scientist to do a systematic evaluation, including pathologic examination of brain tissue, to rule in or exclude cerebral malaria. This practice will reinforce and aid research in progress directed at developing a vaccine and elucidating the role of tumor necrosis factor in this disease. Furthermore, this study will alert the physician to the importance of an effective and well-followed prophylaxis.

Health problems in a large cohort of Americans traveling to developing countries

BACKGROUND

Millions of Americans visit developing countries each year, however, little is known about their health during travel. This study describes health problems in a large cohort of American travelers during and after their trip.

METHODS

A 2-year survey of 784 travelers (95% follow-up) was conducted for persons traveling for < or = 90 days. At the pretravel visit, travelers were given a postcard to record adverse health events. Following travel, standardized telephone interviews were performed for any positive responses, or if the card was not returned. All travelers were contacted 2 months after return to determine late occurring illness and compliance with antimalarials.

RESULTS

Travelers had a mean age of 44 years, a median duration of 19 days, and visited 123 countries. An illness was reported by 64% (1.6 illnesses per traveler). Ill travelers were more often female, and traveled longer than those who were not ill; depending upon destination, each day of travel increased by 3 to 4% the chance of becoming ill. Diarrhea was most common, occurring in 46%; 34% met a strict definition for traveler's diarrhea. Respiratory illness occurred in 26%, skin disorders in 8%, acute mountain sickness in 6%, motion sickness in 5%, accidents and injuries in 5%, and isolated febrile episodes in 3%. Medical care was sought by 8% of all travelers and 12% of those reporting illness. On return, 26% of travelers were ill, 56% of whom became ill after return. Diarrhea, respiratory illness, skin disorders, and febrile syndromes were most common, and 46% of those who were ill sought medical care. Complete compliance with antimalarials was 80%. Noncompliant individuals usually discontinued medications on return. Side effects were reported by 4% of those taking chloroquine, 11% of those taking chloroquine plus proguanil, and 14% of those taking mefloquine, with half of these neuropsychiatric. The incidence of documented malaria was 3.8 cases per 1,000 travelers.

CONCLUSIONS

Many travelers experience adverse health events during and after travel to the developing world. Attention to the prevention and therapy of traveler's diarrhea, prophylaxis of malaria, management of respiratory illness, personal safety, and access to medical care during travel, and, recognition of clinical syndromes after return, will help to improve the traveler's health.

Clinicoepidemiological study of imported malaria in travelers and immigrants to Madrid

BACKGROUND

The number of Spanish travelers visiting malaria endemic areas, and the number of immigrants from malarial countries arriving in Spain are continuously increasing. However, little information about imported cases in Spain is available.

METHODS

A prospective clinicoepidemiological study of imported cases of malaria diagnosed at a referral teaching hospital in Madrid, Spain.

RESULTS

Of the 160 patients, sixty (37.5%) were immigrants and 100 (62.5%) Spanish nationals. Malaria was acquired in Africa by 98.3% of immigrants and in 83.0% of travelers. Falciparum malaria accounted for 71.8% of the cases, P. vivax for 11.9%, P. ovale for 10.6% and P. malarie for 5. 0%. Eleven (6.9%) patients, all immigrants, were asymptomatic. Severe complications were recorded in 17 (10.6%): 7, severe anemia; 3, cerebral malaria; 2, renal failure; 1, spontaneous splenic rupture; 1, acute pulmonary edema; 1, sepsis; 1, acute cerebrovascular accident; and 1, disseminated intravascular coagulation. There were no fatal cases. Among the 100 Spanish nationals, 44% did not follow any prophylaxis, 29% followed a correct prophylaxis, 27% were considered defaulters, and 39% took self-treatment without cure.

CONCLUSIONS

There is a changing pattern of imported malaria in Madrid, with one third occurring in immigrants and two thirds in nationals. This data provides information about the reemergence of imported malaria to Europe.

Survey of use of malaria prevention measures by Canadians visiting India

BACKGROUND

Imported malaria is an increasing problem, particularly among new immigrant populations. The objective of this study was to determine the malaria prevention measures used by Canadians originating from a malaria-endemic area when returning to visit their country of origin.

METHODS

A 35-item English-language questionnaire was administered by interview to travellers at a departure lounge at Pearson International Airport, Toronto, between January and June 1995. Information was collected on subject characteristics, travel itinerary, perceptions about malaria, and pretravel health advice and malaria chemoprophylaxis and barriers to their use.

RESULTS

A total of 324 travellers departing on flights to India were approached, of whom 307 (95%) agreed to participate in the study. Participants were Canadian residents of south Asian origin with a mean duration of residence in Canada of 12.8 years. Most of the respondents were returning to visit relatives for a mean visit duration of 6.8 weeks. Although 69% of the respondents thought malaria was a moderate to severe illness and 54% had sought advice before travelling, only 31% intended to use any chemoprophylaxis, and less than 10% were using measures to prevent mosquito bites. Only 7% had been prescribed a recommended drug regimen. Family practitioners were the primary source of information for travellers and were more likely to prescribe an inappropriate chemoprophylactic regimen than were travel clinics or public health centres (76% v. 36%) (p = 0.003). Respondents who had lived in Canada longest and those with a family history of malaria were more likely to use chemoprophylaxis (p < 0.01).

INTERPRETATION

Few travellers were using appropriate chemoprophylaxis and mosquito prevention measures. Misconceptions about malaria risk and appropriate prevention measures were the main barriers identified.

The Changing Pattern of Imported Malaria in the Academic Medical Centre, Amsterdam

Background: Since 1988, the incidence of malaria imported into the Netherlands has been stable, but the population groups have remarkably changed. Methods: The records of all patients with malaria in the Academic Medical Centre, Amsterdam, between October 1991 and December 1994 were analyzed. Results: Of the 286 patients, 149 (52%) were Dutch citizens and 114 (40%) were originally from malaria endemic areas (92 immigrants, 22 asylum-seekers), whereas between 1979 and 1988 these figures were 85 and 15%. The remaining 23 (8%) patients were 11 children born in the Netherlands to immigrants, 10 foreigners from nonmalarious areas, and 2 for whom the origin is unknown. Plasmodium falciparum was found in 197 (69%) patients, mostly acquired in subSaharan Africa; P. vivax (61 patients, 21%) was mainly acquired in Asia. Two vivax infections proved to be chloroquine-resistant. The compliance with the malaria chemoprophylaxis was poor: only 38% (30/80) of the Dutch citizens and 8% (4/52) of the settled immigrants and children were fully compliant. Severe complicated falciparum malaria developed in 18 (10%) patients, two of whom died. The majority of the falciparum cases were treated with halofantrine or sulfadoxine-pyrimethamine. Artemisinin was used in two. Conclusions: Among the patients with imported malaria, settled immigrants and their (nonimmune) children constitute a growing number. Compliance with chemoprophylaxis is decreasing in Dutch travelers and remains poor in the immigrants. Quinine was increasingly used both as initial treatment for severe falciparum malaria as well as in patients with nonsevere malaria who were nauseated or vomiting.

Information about antimalarial chemoprophylaxis in hospitalised patients--is it adequate?

Malaria remains a huge public health problem worldwide, with over 100 million new cases annually, causing one to two million deaths. This global problem spills over into the UK, with around 2000 cases of reported annually. The proportion of infections due to Plasmodium falciparum (PF) continues to increase and worse still accounts for five to 12 deaths per year. In 1992, Nathwani et al reported the 10 year experience of malaria cases admitted to the Regional Infection Unit, in Aberdeen, Scotland--the "Oil Capital". This study was of interest in that 46% of those British residents who acquired infection had travelled to West or Central Africa on oil related business. The Oil boom of the 1980's appeared to very much centred around Aberdeen and the neighbouring hinterland but did not appear to extend to Dundee which was only 60 miles further down the North-East coast. We, therefore, carried out a retrospective study of patients with malaria admitted to the Regional Infectious Diseases Unit in Dundee over a fifteen year period between 1980 and 1994.

Behavioural aspects of travellers in their use of malaria presumptive treatment

The use of stand-by treatment for malaria by travellers depends on their knowledge, attitudes and behaviour. We examined the behavioural aspects of a cohort of travellers from Switzerland to low-risk malarial areas who, on recruitment, were provided with a kit containing medication for stand-by treatment, guidelines on the diagnosis of malaria, and materials for collection of blood samples for later confirmation of malaria. All subjects were urged to seek medical advice at the first signs of possible malarial symptoms. Illness (fever as the main indicator) was reported by 123 of the 1187 participants, often accompanied by shivering/chills (36.6%), headache (35.0%), gastrointestinal symptoms (69.9%), and myalgia and/or arthralgia (41.5%). Two-thirds of those ill failed to seek medical attention despite their symptoms and pretravel advice. Only 9 (7.3%) were actually beyond the reach of medical attention. The stand-by treatment was self-administered by 6 travellers, only one of whom had confirmed malaria. Two non-serious adverse events were reported. All users consulted a physician after administering the presumptive treatment. This stand-by approach is limited by inappropriate behaviour and poor malaria awareness among travellers. These negative factors can be mitigated by development of an improved kit containing a simple test for self-diagnosis.

Ten-year Experience with Imported Malaria in Bergamo, Italy

Malaria infections have become an increasing public health problem in Europe, especially those imported into nonendemic areas. The transmission and diffusion of malaria has increased, especially over the last decade, due to changes in agricultural practices, vector resistance to insecticides, and most relevantly, increasing international travel and the resistance of these parasites to chemophrophylaxis. This study investigates the epidemiologic factors if imported malaria in an area of Italy, as related to international travel and prophylaxis by Italian immigrants who have revisited their country of origin. All cases (175) of imported malaria detected at the Laboratory of Microbiology of Ospedali Riuniti in Bergamo, Italy, between 1984 and 1993 were studied epidemiologically for the following variables: age, sex, and nationality; travel destination, length of stay, and date of return; and pathogen(s) detected, chemoprophylaxis used, and clinical symptoms exhibited. A high prevalence of Plasmodium falciparum was detected in more than three quarters of the cases with 91.4% of these travelers having visited African countries. Only two subjects had received adequate, correct prophylaxis. Fever, headache, and fatigue were experienced most often; however, in a few cases, blood, exchange transfusion, or treatment for splenomegaly were required. The results indicate that there is an emerging public health problem with immigrants who have resided in Italy for some time, revisited their country of origin, and consequently become infected with malaria, with specific prophylaxis not having been provided. This study emphasizes the importance of local epidemiologic studies, effective prophylaxis, and the need for those involved in the travel industry to promote specialized pretravel advice on a routine basis.

West African Immigrants and New Patterns of Malaria Imported to North Eastern Italy

With the settlement of increasing numbers of immigrants from tropical African countries into Italy over the last decade, the epidemiologic pattern of imported malaria underwent significant change. Italian immigrants originating from endemic areas who revisit their country of origin have exhibited an increasing incidence of malaria: the Italian Ministry of Health recorded an increase of from 14% in 1986 to 40.4% in 1991. This retrospective study reviews the epidemiology of all malaria cases recorded from 1988 to 1991 in a regional reference center in North Eastern Italy. Epidemiologic factors, including the details of their travel experience, were examined for all cases, and the relation of immigrants to Italian-born citizens were compared. Of the 100 cases recorded during this period, 36 were diagnosed in 1988-1989 and 64 in 1990-1991. Immigrants accounted for six times more cases during the latter than during the former time period. Compared to nonimmune short-term travelers, immigrants experienced significantly milder forms of the disease and lower levels of parasitemia (Plasmodium falciparum) on admission. Notably, 10 cases of malaria in immigrants were not recognized at first observation on microbiology. With the advent of this new risk group of immigrants that originate from endemic countries, especially those making occasional short visits to their native countries, this new epidemiologic profile of malaria imported into Italy shows the need for improvement in the areas of prophylaxis, pretravel education, and diagnostic services.

Effects of Ill Health on the Service of Scottish Presbyterian Missionaries 1867-1929

The experience of Scottish Presbyterian missionaries serving overseas between 1867 and 1929 was analyzed. Data were compiled during a 4-year postgraduate research program from such sources as the General Assembly Reports of the Foreign Mission Committees of the Church of Scotland, numerous missionary magazines, school records, medical directories, and newspaper and medical journal obituaries. Data show that the year of appointment, the mission station and continent location, and medical knowledge were all influencing factors on the length of missionary service, early retirement on account of ill health, death in service, and age at death. This method of comparative, historical study may have further useful applications in looking at the health experience of other groups who lived and worked abroad at the turn of the century, such as civil servants, the military, or other comparable missionary groups.

Comparison of three regimens for malaria prophylaxis in travellers to east, central, and southern Africa

OBJECTIVES

Confirmation of breakthroughs in three different malaria chemoprophylactic regimens (chloroquine 300 mg weekly and proguanil 100 mg daily; chloroquine 300 mg weekly and proguanil 200 mg daily; proguanil 200 mg daily) and assessment of compliance.

DESIGN

Prospective, randomised multicentre trial.

SETTING

Five vaccination centres in the Netherlands.

SUBJECTS

Dutch travellers to east, central, and southern Africa.

MAIN OUTCOME MEASURES

Plasmodium falciparum seen on blood film; concentrations of drugs measured in blood spots.

RESULTS

P falciparum infection was confirmed in 12 (21%) of 58 travellers with fever suspected to be due to malaria. No difference in prophylaxis failures between the regimens was found. Breakthroughs were difficult to confirm, as compliance could be determined in only 30% of the participants with fever and chloroquine in their regimen. One breakthrough was proved. The risk per 1000 people per month for travellers was 5.4 (95% confidence interval 2.4 to 12.6) for chloroquine 300 mg weekly and proguanil 100 mg daily, 2.8 (0.9 to 10.1) for chloroquine 300 mg weekly and proguanil 200 mg daily, and 6.0 (2.6 to 14.0) for proguanil 200 mg daily.

CONCLUSION

Prophylaxis failures occurred in less than 1% of the participants, and only 21% of those with a fever were suffering from falciparum malaria. Compliance was moderate. The chloroquine-proguanil combination can still be recommended for visitors to east, central, and southern Africa.

Malaria in Aberdeen: an audit of 110 patients admitted between 1980-1991

All 110 patients seen in North East Scotland after contracting malaria from foreign travel were treated in the Regional Infection Unit in Aberdeen. Those patients managed there from January 1980 to March 1991 are described. There were 54 episodes of Plasmodium falciparum malaria (49%) and 26 episodes (23%) of Plasmodium vivax malaria. The remainder had either mixed infection or were diagnosed as malaria on high clinical probability. The majority of the patients were male (80%) and under 40 years of age (84%). Most patients were either caucasians born in the UK (69%) or native Africans (23%) who were students recently arrived for further education or who had returned from visiting their country of origin for summer holidays. The British residents acquired infection either while on oil related business in West or Central Africa (46%) or after travelling on holiday (30%). The peak incidence of presentation was August and September. 93.5% of patients with falciparum malaria had returned or originated from Africa. 42% with vivax malaria had visited Africa and 27% Papua New Guinea. 70% had been prescribed antimalarial prophylaxis but less than half of these took their medication correctly. The majority of patients with falciparum malaria presented within two weeks of arrival in Britain while patients with vivax malaria presented at varying (but generally longer) intervals, 42% being diagnosed more than three months after exposure. Falciparum infection was more severe although there have been no deaths in the unit from malaria. Our experience seemed of interest and worth reporting because of the number of patients whose infection reflected travel related to the off shore oil industry, which is centred in Aberdeen.

Travellers' malaria

The risk of malaria poses travellers and their advisers with difficult problems as drug resistance spreads worldwide. Protection against infection rests on travellers' knowledge of the risk of malaria, on their avoidance of malaria vectors and on their compliant use of chemoprophylaxis. In this article, Robert Ste f fen and Ronald Behrens explain that one of the priorities for reducing malaria morbidity is to improve travellers' use of personal protection against mosquito bites. They show that none of the drugs, or combinations thereof, provide a 100% efficacy, owing to increasing drug resistance, mainly of Plasmodium falciparum. The commonly used drugs for malaria prophylaxis (mefloquine, doxycycline, chloroquine and proguanil) often cause minor side effects. All, except proguanil, have also been occasionally associated with severe adverse effects. Other drugs (pyrimethaminelsul fadoxine, amodioquine) are not suitable for chemoprophylaxis because of unacceptable adverse reactions. The use of drugs for self therapy is constrained by limitations of toxicity and efficacy, and the added difficulties of defining indications for safe and appropriate use.

Changing patterns of malaria in south-east Scotland: implications for practitioner awareness and prophylactic advice

The medical records of all 229 patients with malaria admitted to the Edinburgh City Hospital between 1969 and 1988 were studied retrospectively. A total of 137 were from Africa, 44 from the Indian subcontinent, 19 from the Far East, 18 from New Guinea, 5 from the Middle East and 3 from South America. The number of yearly admissions rose markedly after 1983, mainly due to an increase in Plasmodium falciparum cases. Ninety-four cases (15 with severe parasitaemia) mainly from Kenya and Nigeria were due to P. falciparum infection and 99 to P. vivax. There were no deaths. A seasonal distribution of onset of fever in patients with P. vivax infections originating from the Indian subcontinent showed that most patients presented during the summer. Prophylaxis had generally been irregular or non-existent but many compliant patients may have been receiving an inadequate dose of chloroquine on a mg/kg body weight basis. General practitioners are likely to see at least one case of malaria every 4 years. They are encouraged to seek advice from a specialist unit whenever necessary whether before or after their patient travels abroad. Travellers, in particular to Kenya and Nigeria, and Asian immigrants to the UK returning on holiday to their country of origin should be strongly advised to take regular prophylaxis including on return to the UK.

Acute gastroenteritis: the need to remember alternative diagnoses

Five hundred and ninety-four patients were consecutively admitted to an infectious disease unit over a 2-year period with a referral diagnosis of acute gastroenteritis or food poisoning. In 175 (29%) patients, gastrointestinal symptoms were associated with a condition other than gastrointestinal infection. Non-infective gastrointestinal disease was present in 90 patients, systemic infection in 50 and systemic disease in 35. Four illustrative case histories are presented to emphasize the need for a high index of suspicion if diseases such as malaria, septicaemia or appendicitis are not to be missed.

A cumulative review of studies on travellers, their experience of illness and the implications of these findings

A cumulative review of illness experienced by 13,816 travellers returning to Scotland since 1977, shows an overall attack rate of 36%. Alimentary complaints predominated; 18% of travellers had these alone and a further 10% had other symptoms as well as their gastro-intestinal disorder. Higher attack rates were noted in those taking package holidays. Inexperience of travel, smoking, more southerly travel and younger age (particularly those between 20- and 29-years-old) were other contributing factors. A similar pattern emerged from a I year study of hospital in-patients with travel related admissions. Serological studies of 470 travellers showed that 20% had incomplete immunity to poliomyelitis; 25% of those tested (312 travellers) had serological evidence of typhoid immunisation, I.9% (of 760 travellers) had antibodies to Legionella pneumophila, 64% (5II travellers tested) had antibodies to hepatitis A, 87% (288 tested) had adequate levels of tetanus antitoxin but only 40% of the 225 travellers tested had adequate levels of diphtheria antitoxin. Amongst a subgroup of 645 travellers the travel agent was the most frequently consulted source of pre-travel health advice. This carries particular significance for the dissemination of relevant advice in view of the inadequacies found from study of the health information in travel brochures. These findings, viewed against the perspective of the continuing growth in international travel, means that travellers, the medical profession, the travel trade, health educators, global health agencies and health authorities in those countries accepting and encouraging tourists, will be required to recognise the health implications of further tourism development if this problem of illness associated with travel is to be brought under control.

Malaria prophylaxis in travellers to tropical Africa

This study investigated travellers to tropical Africa with regard to prophylactic treatment of malaria. A total of 5703 travellers completed a questionnaire on their flights back to the Federal Republic of Germany; 4116 passengers (73.7%) had visited East Africa, while 808 (14.5%) had been to West Africa. The results indicate that 90.2% took a regular chemoprophylaxis against malaria. Nevertheless, 8.1% of the travellers used no antimalarials and in 9.3% chemoprophylaxis was inadequate due to inappropriate advice; for example, 7.5% still took pyrimethamine-sulfadoxine as prophylactic. Mefloquine was correctly taken by 38.9% of the travellers in East Africa; 12.6% used it in West Africa where it is not necessary. Antimosquito measures have a high priority for travellers to tropical Africa and dissemination of this fact must be improved since only 72.6% followed through on such advice.

Malaria in Leicester 1983-1988: a review of 114 cases

We have reviewed 114 episodes of malaria in 110 patients who were admitted to the Infectious Diseases Unit in Leicester during the 5 year period from February 1983-January 1988. There were 71 episodes of vivax malaria (62%), 33 episodes of falciparum malaria (29%), four patients with mixed infection and six patients with negative blood films who were diagnosed on clinical suspicion alone. Most patients presented in the summer months, 68% were aged under 40 years, 39% were born in the Indian subcontinent, 23% in East Africa and 23% in Britain. Eighty-two per cent of patients with falciparum malaria had recently returned from Africa whereas 82% with vivax malaria had visited Asia. Thirty six per cent had been given antimalarial chemoprophylaxis but only half of these took medication correctly. Seventy five per cent of episodes of falciparum malaria presented within 2 weeks of arrival in Britain, however vivax malaria could present at any time and 49% of cases occurred over 3 months after exposure. Presenting symptoms and signs were often non-specific. Twenty nine per cent of patients had been treated with antibiotics and 11% received antimalarials prior to admission. Vivax malaria was generally a mild infection but falciparum malaria was often severe with 39% of patients experiencing complications including one death. Although Plasmodium vivax and P. falciparum are morphologically similar the diseases caused by the two species of parasite are quite distinct. Physicians must ensure that malaria is excluded in anyone who has travelled to an endemic area.

Risk of malaria in British residents returning from malarious areas

OBJECTIVES

To identify which British residents travelling abroad are at greatest risk of malaria infection, and to determine the efficacy of malaria chemoprophylaxis for preventing P falciparum infections in tropical Africa.

DESIGN

Prospective cohort study (case-base linkage) with routine national surveillance systems. Denominators (base population) were obtained from monitoring a random sample of returning British travellers with the international passenger survey. Numerators (cases) were obtained from reports of malaria infections in British residents, through the Malaria Reference Laboratory network.

SETTING

International passenger survey conducted at passport control of international airports in Britain. Malaria reports received nationally were collated centrally in London.

SUBJECTS

2948 British residents (0.2%) returning to Britain in 1987 randomly selected and questioned and 1052 British residents with microscopically confirmed malaria infections in 1987, whose case reports were reviewed and on whom additional data were collected by postal survey.

MAIN OUTCOME MEASURES

Annual incidence subdivided by categories of risk. Chemoprophylactic efficacy for east and west Africa by principal regimens and compliance.

RESULTS

Annual rates of reported infection per 100,000 travellers to Oceania were 4100; to west and east Africa were 375 and 172 respectively; to Latin America, the Far East, and the Middle East were 12, 2, and 1 respectively. Immigrants visiting friends and relatives in Ghana and Nigeria were at greatest risk (1303 and 952 per 100,000 respectively) in west Africa. Business travellers to Kenya experienced the highest attack rates in east Africa (465 per 100,000). Age-sex specific attack rates varied by region. No prophylaxis was reported to have been used by 23% of British visitors to west Africa, 17% to east Africa, 46% to central or southern Africa, and 58% visiting south Asia. The efficacy of chloroquine plus proguanil against P falciparum infection was 73% and 54% in west and east Africa respectively. Lower values were obtained for chloroquine alone and proguanil alone. The efficacy of Maloprim (pyrimethamine-dapsone) was 61% in west Africa, but only 9% in east Africa. Visitors to west Africa who did not comply with their chemoprophylactic regimen were at a 2.5-fold higher risk of infection than fully compliant users. Non-compliant visitors to east Africa had similar rates of infection as non-drug users.

CONCLUSIONS

In 1987 chloroquine plus proguanil was the preferred chemoprophylactic regimen for P falciparum infection in Africa; antimalarial drugs must be taken regularly to be effective.

Treatment of malaria--1990

Malaria has become an increasingly common health problem in the 1970s and 1980s, both in areas where infection is endemic and in travellers returning to non-endemic areas. The severity of infection varies widely, depending on the plasmodial species involved, and there is an extensive chemotherapeutic armamentarium currently available to combat malarial infection. Drug chemistry, pharmacokinetics, mechanism of drug action and resistance, and toxicities are outlined for the cinchona alkaloids (quinine and quinidine), chloroquine, amodiaquine, pyrimethamine, the sulphonamides, pyrimethamine/sulfadoxine, mefloquine, pyrimethamine/sulfadoxine/mefloquine, the sesquiterpene lactones, primaquine, and other drugs. A knowledge of the distribution of drug resistance is vital for the provision of effective antimalarial therapy, and current information in this area is outlined. Chloroquine remains the mainstay of treatment for the erythrocytic stages of Plasmodium vivax, P. ovale, P. malariae, and chloroquine-sensitive P. falciparum malaria. The dormant hepatic stages of P. vivax and P. ovale also require further treatment with primaquine. Quinine, alone or in combination with other drugs, is the primary agent used to treat chloroquine-resistant falciparum malaria. Falciparum infection can rapidly become fatal, therefore its complications of multiple organ failure, heavy parasitaemias, cerebral malaria, and hypoglycaemia must be recognised and managed promptly. Because these protozoal parasitic infections are now encountered throughout the world and can become life-threatening, a wide variety of practitioners must become more familiar with their correct treatment.

Malaria incidence and prevention among European and North American travellers to Kenya

A longitudinal survey was conducted among travellers departing from Nairobi airport to determine the use of malaria prevention measures and assess the risk for malaria while travelling in Kenya. Among 5489 European and North American travellers, 68 different drug regimens were used for prophylaxis, and 48% of travellers used both regular chemoprophylaxis and more than 1 antimosquito measure during travel; 52% of 3469 travellers who used chemoprophylaxis did so without interruption during their travel and for 4 weeks after departure. Compliance was lowest among travellers who visited friends and relatives, who were young, or who stayed more than 3 weeks. Sixty-seven (1%) travellers experienced symptoms of malaria, but the diagnosis could be verified for only 16 of these. Long-stay travellers appeared to be at higher risk for malaria than short-stay travellers, and health information needs to be targeted especially to the former. Similar investigations are needed among international travellers to other malaria-endemic countries. With comparable data available, consistent and effective malaria prevention guidelines can be developed.

Malaria prophylaxis in travellers from Britain

A short questionnaire about malarial prophylaxis was completed by 376 travellers departing from Gatwick Airport to destinations in Asia, Africa, Australasia and South or Central America. Only 263 (70%) had sought advice, 80% of them from a general practitioner. Of travellers born in Britain, 81% had sought advice compared to 38% of those born abroad (P less than 0.001). Advice about protective measures to reduce mosquito bites had been given to 52% travellers. Although 264 were travelling to areas where prophylaxis is advised, only 167 (63%) were taking antimalarials, while 22% travelling to malaria-free destinations were taking unnecessary prophylaxis. Many British travellers do not take effective antimalarial chemoprophylaxis. This has undoubtedly contributed to the recent increase in incidence of the disease in the U.K. General practitioners should ensure that they give correct advice and the immigrant population need to understand the risk of malaria when they return home.

Malaria--an overview

The epidemiology, clinical features, diagnosis, prognosis, management, chemotherapy and chemoprophylaxis of malaria are reviewed.

History of malaria in England

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Development of recommendations for the protection of short-stay travellers to malaria endemic areas: Memorandum from two WHO Meetings

In the past, since malaria chemoprophylaxis was assumed to be of benefit and with no serious complications, it was recommended to all travellers who were at risk of acquiring the disease. The current epidemiological situation of malaria is marked by the increasing spread of Plasmodium falciparum resistance to chloroquine and by problems due to the toxicity of other drugs. Recommendations for malaria prophylaxis should therefore be based on an epidemiological approach which takes into account the risk of acquiring the infection, the toxicity and effectiveness of the available antimalarial drugs, the traveller's perception of these risks, and the human factors that influence the use of all possible protective measures against malaria.This Memorandum describes the epidemiological approach and the data bases required for the development of recommendations on prophylaxis for short-stay visitors in malaria endemic areas, and gives guidelines on the protective measures and drugs that may be used in defined situations.