Mefloquine compared with other malaria chemoprophylactic regimens in tourists visiting East Africa

Steffen, Robert; Fuchs, Elisabeth; Schildknecht, Janine; Naef, U.; Funk, Maia; Schlagenhauf, Patricia; Phillips-Howard, Penelope A.; Nevill, C.G.; Stürchler, D

doi:10.1016/0140-6736(93)90814-w

Cited by 235 publications

(108 citation statements)

References 12 publications

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“…Notwithstanding the destination, the percentage of patients with a positive antibody response to CS antigen tended to be considerably higher than previous risk estimates (Table 1). 11 Areas with a comparatively low risk of malaria infection, but not necessarily significant differences between positive and negative travelers were Central America (RR ϭ 0.86, P Ͻ 0.001), the Indian subcontinent (RR ϭ 0.45, P ϭ 0.015), South America (RR ϭ 0.49, P ϭ 0.091), East Asia (RR ϭ 0.68, P ϭ 0.441), West Asia (RR ϭ 0.24, P ϭ 0.099), and Southeast Asia (RR ϭ 0.69, P ϭ 0.094). No significant differences regarding sex or age between patients testing positive or negative for CS antibodies were detectable.…”

Section: Discussionmentioning

confidence: 99%

“…On the basis of such data, the risk for malaria infection for unprotected travelers to West and East Africa has been estimated to be approximately 1.2% per month. 11 The recommendations for prophylactic measures against malaria infection for travel to malarious areas are based in part on such estimates, depending on the anticipated infection rate and drug resistance in P. falciparum. Generally, precautions to avoid mosquito bites and strict intake of antimalarials assumed to be effective against most endemic strains of P. falciparum are emphasized.…”

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confidence: 99%

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Assessing the incidence of infection with Plasmodium falciparum among international travelers.

Jelı́nek

Blüml²,

Löscher³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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Abstract. Circumsporozoite (CS) antibodies, indicating plasmodial infection but not necessarily development of disease, have been shown to be reliable indicators of transmission in endemic areas. To estimate the actual rate of plasmodial infection, the prevalence of CS antibodies was investigated by an ELISA test system in a selected population of 2,131 travelers returning from areas endemic for malaria who presented to an outpatient clinic without any apparent symptom or clinical sign of malaria. Serum specimens from 104 of the investigated 2,131 patients (4.9%) were found to be positive (titer Ն 6.25 international ELISA units [IEU]). The geometric mean titer of antibody concentrations (IEU) in seropositive patients was 18.64 IEU (95% confidence interval [CI] ϭ 13.15-24.13), while it was 2.1 IEU (95% CI ϭ 1.8-2.4) in seronegative patients. A significantly above average risk for plasmodial infection could be found among travelers to East Africa (risk ratio [RR] ϭ 4.5, P Ͻ 0.001), West Africa (RR ϭ 4.5, P Ͻ 0.001), and Southern Africa (RR ϭ 3.2, P ϭ 0.015), while areas with a comparatively low risk included Central America (RR ϭ 0.86, P Ͻ 0.001 ), the Indian subcontinent (RR ϭ 0.45, P ϭ 0.015), South America (RR ϭ 0.49, P ϭ 0.091), East Asia (RR ϭ 0.68, P ϭ 0.441), West Asia (RR ϭ 0.24, P ϭ 0.099), and Southeast Asia (RR ϭ 0.69, P ϭ 0.094). The results of this study emphasize the importance of adequate malaria chemoprophylaxis in nonimmune travelers to endemic areas. By use of the described method, estimates of the true infection rate of malaria in travelers can be derived for certain areas and the value of prophylactic measures can be demonstrated.The first antigens that are presented to the immune system of a host who is infected with malaria parasites are the surface antigens of plasmodia sporozoite stages expressed shortly after inoculation by the anopheline vector. For a few hours, the immune system of the infected host may produce protective antibodies before the parasites invade liver cells and transform to merozoite stages. Antibodies to sporozoites of Plasmodium spp. are directed against a major surface antigen, the circumsporozoite (CS) protein. Therefore, the detection of significant titers of antibodies to CS protein in a person indicates previous inoculation with sporozoites, not necessarily the development of disease. The immunodominant epitope of the P. falciparum CS protein consists of highly conserved tandem repeats of amino acids (Asn-AlaAsn-Pro ϭ NANP) 1 . Several NANP repeats of variable length have been synthesized using either chemical 1 or recombinant DNA techniques, 2 and a variety of immunoassays have been tested to detect humoral immunity to P. falciparum sporozoites. 1,3 An ELISA kit using a chemically synthesized (NANP) 40 peptide is available. 3 In individuals living in endemic areas, the prevalence and level of sporozoite antibodies have been shown to correlate with the entomologic inoculation rate assessed at the same time for the same area, and the development of detectable titers ...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Assessing the incidence of infection with Plasmodium falciparum among international travelers.

Jelı́nek

Blüml²,

Löscher³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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“…[1][2][3][4][5] This method is likely to underestimate true incidences of malaria because antimalarial treatment is frequently started without reliable parasitologic confirmation. In addition, this method will result in underestimation of the exposure to P. falciparum when the travelers studied take chemoprophylaxis.…”

mentioning

confidence: 99%

Testing for anti-circumsporozoite and anti-blood-stage antibodies for epidemiologic assessment of Plasmodium falciparum infection in travelers.

Cobelens

Verhave²,

Leentvaar-Kuijpers³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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Abstract. The purpose of this investigation was to assess the role of serology for establishing incidences of Plasmodium falciparum malaria and of exposure to P. falciparum in epidemiologic studies of travelers using chemoprophylaxis. The design was a prospective cohort study involving 548 short-term Dutch travelers to areas endemic for P. falciparum malaria. Sera were collected before departure and, together with the medical history, 2-6 weeks after return. All sera were tested for anti-circumsporozoite (CS) antibodies by an R32tet 32 -ELISA; sera of subjects reporting febrile illness during travel or after return or with anti-CS responses were tested for anti-blood-stage antibodies by an indirect fluorescence antibody test (IFAT). Five subjects (0.9%) reported P. falciparum malaria confirmed by thick blood smear examination (documented cases) and six (1.0%) reported treatment for malaria without a documented diagnosis (presumptive cases). Conversions in the IFAT were detected in six subjects, including all five documented cases and one presumptive case. Anti-CS antibodies were detected in seven subjects (1.3%), including three documented cases and four of 442 subjects with no history of fever or malaria treatment (0.9%). Incidence rates per 1,000 person-months of travel (95% confidence interval) of infection with P. falciparum, whether or not suppressed by chemoprophylaxis, were 16.9 (8-31) for all destinations and 91.6 (33-200) for West Africa. In epidemiologic studies of P. falciparum malaria in travelers, testing for antibodies to blood stages can increase the sensitivity and specificity of case detection; testing for antibodies to sporozoites may be useful for the assessment of exposure to P. falciparum in travelers using chemoprophylaxis, but the sensitivity is limited.In most epidemiologic studies that assess risks of Plasmodium falciparum malaria or efficacies of prophylactic measures in nonimmune travelers, incidences are based retrospectively on cases of malaria that are confirmed by blood slide evaluation.

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“…23,24 There are only few evidencebased studies available regarding the risk of infection in trav-elers. [25][26][27][28] Prescribing practices vary to a great extent between different countries. While in Europe "stand-by-medication" is used for many malaria-endemic areas without high endemicity, in the USA a stand-by-medication strategy is not established.…”

Section: Malaria Prophylaxismentioning

confidence: 99%

Pre-Travel Vaccinations and Malaria Prophylaxis for International Travelers

Pavli¹,

Maltezou²

2017

Public Health Open J

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Mefloquine compared with other malaria chemoprophylactic regimens in tourists visiting East Africa

Cited by 235 publications

References 12 publications

Assessing the incidence of infection with Plasmodium falciparum among international travelers.

Assessing the incidence of infection with Plasmodium falciparum among international travelers.

Testing for anti-circumsporozoite and anti-blood-stage antibodies for epidemiologic assessment of Plasmodium falciparum infection in travelers.

Pre-Travel Vaccinations and Malaria Prophylaxis for International Travelers

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