Ahmed H. Omar,
Honorary Research Assistant
Ottawa General Hospital Campus, ON, K1H 8L6, Canada,
Anne E. McCarthy, Associate Professor of Medicine
Send response to journal:
Re: Preventing malaria in travellers, the HIV patient.
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We read with interest the review by Lalloo and Hill (1), but we were surprised
to see no mention of an important risk group, the HIV positive traveller. The
advent of highly active antiretroviral therapy (HAART) has markedly improved
the health and quality of life for these individuals, allowing them to live
full and active lives, this includes travel to malaria endemic areas
(2). The counselling of these patients requires an accurate risk
assessment taking into account the level of immune compromise and the risks
involved in travelling to tropical countries (3, 4).
HIV-infected adults are more prone to acquiring malaria and are at an
increased risk of severe malaria and death. Therefore, prevention of malaria
is even more important in these individuals.
Patients’ awareness of malaria risk is crucial. A 2006 survey in our
department of 124 HIV-infected patients, showed that 46% of patients (N=19/41)
with recent travel had visited a country with a malaria risk (5).
Interestingly, of 21 patients born in malaria endemic countries, nine (43%)
stated that their birth country was not at risk of malaria, a lack of
awareness which may prevent seeking appropriate precautions prior to travel.
Consistent with these findings, a survey of 130 HIV patients living in Toronto
who travelled internationally showed that more than 50% visited malaria areas,
but only 7% had taken chemoprophylaxis (6). These results suggest that a
significant number of HIV patients travel to malaria endemic areas, but a
portion of them may not be taking adequate chemoprophylaxis.
An important issue is the possible toxic interaction of antimalarials with
antiretroviral drugs. This is more complicated if their regimen includes a
protease inhibitor, shown to be the case in approximately 60% to 70% of HIV
patients in Ottawa and Toronto-based centres (5, 6).
Special consideration needs to be made for patients going to areas of
Chloroquine Resistant Plasmodium Falciparum Malaria (CRPF). The
current first-line drugs recommended by the Public Health Agency of Canada for
CRPF malaria include Doxycycline, Mefloquine and Atovaquone/Proguanil
(Malarone) (7). There remains a paucity of data about the safe use of these
drugs with HIV therapy. A study conducted at our institution demonstrated a
concerning 40% decrease in Ritonavir levels when co-administered with
Mefloquine (8). Doxycycline is often utilised in this travelling population,
but must be continued for four weeks after leaving the malaria-endemic areas.
Malarone is well tolerated and only requires continuation for 7 days after
malaria exposure, thus having a potential to limit pill burden in this
population. Currently there is a lack of data on the safety and
potential interactions of Malarone with protease inhibitors (9). Future
research is important to establish its safety in this context.
Patient counselling is imperative in this setting and until more data is
available, the choice of malaria chemoprophylaxis for HIV positive travellers
on HAART remains limited and will need careful selection.
Dr. Ahmed H. Omar, Honorary Research Assistant.
Dr. Anne E. McCarthy, Associate Professor of Medicine.
Division of Infectious Diseases, the Ottawa Hospital General campus, Ottawa,
Canada.
E-mail correspondence: ahomar@toh.on.ca or amccarthy@ottawahospital.on.ca
References:
1. Lalloo DG, Hill DR. Preventing malaria in travellers. BMJ
2008;336:1362-1366 (14 June), doi:10.1136/bmj.a153.
2. Castelli F, Patroni A. The human immunodeficiency virus–infected
traveller.Clin Infect Dis 2000; 31:1403–1408.
3.
Malaria
and HIV interactions and their implications for public health policy. Geneva,
Switzerland, WHO. Technical Consultation. 2004.
4. McCarthy AE, Mileno MD. Prevention and treatment of travel-related
infections in compromised hosts.Curr Opin Infect Dis. 2006 Oct;19(5):450-5.
5. Béïque L, Denommé N, la Porte C, Thibert J, McCarthy AE: Travel Survey
among Canadian HIV-Infected patients PO01.05 10th Conference of the
International Society of Travel Medicine (CISTM10). Vancouver May 20-24, 2007.
6. Salit IE, Sano M, Boggild AK, Kain KC. Travel patterns and risk behaviour
of HIV-positive people travelling internationally. CMAJ
2005;172(7):884-8.
7.
Health
Canada. Canadian recommendations for the prevention and treatment of malaria
among international travelers. CCDR 2004;30S1: 1-62.
8. Khaliq Y, Gallicano K, Tisdale C, et al. Pharmacokinetic interaction
between mefloquine and ritonavir in healthy volunteers. Br J Clin Pharm
2001;6: 591-600.
9. Khoo S, Back D, Winstanley P. The potential for interactions between
antimalarial and antiretroviral drugs. AIDS 2005; 19: 995-1005.
Competing interests:
None declared |
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Preventing malaria in travellers, the HIV patient.
