Archive for the ‘travel medicine’ Tag

What are the international travel requirements regarding yellow fever immunisation status?   Leave a comment

WHO recommends YF vaccination for travel to:
AFRICA: Angola | Benin | Burkina Faso | Burundi | Cameroon | Central African Republic | Chad | Congo | Cote d’Ivoire | Democratic Republic of the Congo | Equatorial Guinea | Ethiopia | Gabon | Gambia | Ghana | Guinea | Guinea-Bissau | Kenya | Liberia | Mali | Mauritania | Niger | Nigeria | Rwanda | Sao Tome and Principe | Senegal | Sierra Leone | Somalia | Sudan (except Khartoum) | Togo | Uganda | United Republic of Tanzania

AMERICAS: Argentina (north and northeastern forested areas, including Iguacu Falls and all areas bordering Brazil and Paraguay) | Bolivia (except: La Paz, Sucre) | Brazil (except: Rio de Janeiro, Sao Paulo, Salvador, Recife, Fortaleza) | Colombia | Ecuador (except: Guayaquil, Quito, Galapagos Islands) | French Guiana | Guyana | Panama (except: Canal Zone, Panama City, San Blas Islands) | Paraguay | Peru (except: Cuzco, Machu Picchu) | Suriname | Trinidad and Tobago (except Tobago only) | Venezuela


The following countries require documentary proof of YF vaccination from all incoming travelers:

  1. *ICVP (International Certificate of Vaccination or Prophylaxis) for yellow fever MUST be completed; is valid ten days after vaccination and for a period of ten years. Available online from the WHO Press or the US Government Bookstore. A PDF copy may also be downloaded here.

  2. Note: most countries, including Singapore, require proof of valid vaccination against yellow fever for travelers arriving from, or having transited through, a country within the YF-endemic zone. However, the countries listed below require all arriving travelers to have documentation of yellow fever vaccination regardless whether they are arriving from a yellow fever-endemic or non-endemic country.

AFRICA: Angola | Benin | Burkina Faso | Burundi | Cameroon | Central African Republic | Chad | Congo | Cote d’Ivoire | Democratic Republic of the Congo | Gabon | Ghana | Liberia | Mali | Mauritania (except: from non-endemic zone staying < 2 weeks) | Niger | Rwanda | Sao Tome and Principe | Sierra Leone | Togo

AMERICAS: French Guiana | Bolivia (unless affidavit signed exempting the state from liability)

  1. CDC Travelers’ Health — Yellow Book 2008. Chap 4: Prevention of Specific Infectious Diseases: Yellow Fever [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; 2007 June 20. [updated 2009 Apr 17; cited 2009 Apr 22]. Available from:

  2. WHO: International Health Regulations (IHR) | International Certificate of Vaccination or Prophylaxis (ICVP) [Internet]. World Health Organisation. Available from:

  3. CDC Travelers’ Health — Yellow Book 2008. Chap 5: Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, By Country [Internet]. Atlanta (GA): Centers for Disease Control and Prevention. [cited 2009 May 27]. Available from:


Posted November 17, 2009 by absinthemisia in vaccination, yellow fever

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Where is yellow fever endemic?   1 comment

Central & South America
at highest risk: Bolivia | Brazil | Colombia | Ecuador | Peru
also at risk: Panama | Venezuela | Guyana | Suriname | French Guiana | Paraguay | Argentina (Northern border)

(generally countries within a band 15degN to 10degS of the equator)
at highest risk: Togo | Mali | Senegal | Burkina Faso | Cameroon | Benin | Sierra Leone | Nigeria | Liberia | Guinea | Ghana | Cote d’Ivoire

The following countries in Africa are not endemic for yellow fever:
Northern Africa: Western Sahara | Morocco | Algeria | Libya | Gibralta (UK) | Malta | Tunisia | Egypt | Eritrea | Djibouti
Southern Africa: Namibia | Botswana | Zambia | Malawi | Mozambique | Zimbabwe | South Africa | Lesotho | Swaziland


  1. CDC Travelers’ Health — Yellow Book 2008. Chap 4: Prevention of Specific Infectious Diseases: Yellow Fever [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; 2007 June 20. [updated 2009 Apr 17; cited 2009 Apr 22]. Available from:

  2. News release: More funding urged for yellow fever vaccine stockpile [Internet]. Geneva: World Health Organisation; 26 May 2009 [cited 27 May 2009].

Posted May 27, 2009 by absinthemisia in yellow fever

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What are some non-pharmacological interventions in prophylaxis against malaria?   Leave a comment

  • malaria endemic areas (see WHO world map)

  • Anopheles mosquitoes bite between dusk and dawn; the lifetime range of flight of an Anopheles mosquito is 1km. Hence, daytime side trips to areas where malaria is endemic present little risk, if the traveler restricts nighttime hours to air-conditioned hotels or other environments where there are few mosquitoes.

  • travel restricted to capital cities and other urban areas (as is typical of business travel) is associated with an insignificant risk of malaria, despite the risk in areas nearby, with the exception of sub-Saharan Africa and certain cities in India.

  • take into account the possibility of deviation from the preset itinerary brought to the pretravel consultation.

Non-pharmacological interventions

  • wear long sleeves, long pants, and fully closed shoes with socks after dark.

  • use permethrin-treated mosquito nets if accommodations are neither well screened nor air-conditioned.

  • repellent containing 30-50% DEET (N,N-diethyl-3-methylbenzamide) should be applied to exposed areas of skin every 4-6 hours; more frequent applications is required for agents containing lower concentrations.
    Children: up to 30% DEET is considered to be safe (higher concentrations have not been tested).
    Pregnancy: up to 20% DEET has been shown to be safe.

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What are the salt & base equivalents for antimalarials?   Leave a comment

by convention, quinine dosage is given in salt units while its derivatives are usually given in base units, except for mefloquine which is complicated. The highlighted units below are the ones in common use. Remember to state clearly whether you are referring to the base or salt when writing the prescription! This discussion applies to oral formulations only.

Quinine sulphate: 300mg salt = 250mg base

Chloroquine phosphate: 150mg base = 250mg salt

Hydroxychloroquine: 155mg base = 200mg salt

Mefloquine hydrochloride: 250mg salt = 228mg base (in the United States)
(however, in some countries mefloquine is available as 250mg base which = 274mg salt; in these countries I presume that “250mg mefloquine” refers to the base formulation, and patients receive a 9.6% higher dosage than their counterparts elsewhere. But, most internationally-recognised publications refer to the 250mg salt formulation available in the US.)

Amodiaquine hydrochloride: 200mg base = 260mg salt

Primaquine phosphate: 15mg base = 26.3mg salt


  1. White NJ. The Treatment of Malaria. N Engl J Med 1996 Sep 12;335(11):800-806.
  2. Freedman DO. Malaria Prevention in Short-Term Travelers. N Engl J Med 2008 Aug 7;359(6);603-12. Table 3, Drug Regimes for Prophylaxis Against Malaria; p.608.
  3. Lariam package insert (Roche – US), rev Sep 2008 (PDF file)
  4. (Archived) [Internet]. c2000-2009 [revised 2001 Jan 24; cited 2009 May 8]. Available from:

Yellow Fever Vaccine and Schedule   Leave a comment

Live attenuated vaccine produced in chick embryos. For purposes of international travel, yellow fever vaccine must be manufactured by a WHO-approved manufacturer and and administered at a WHO-approved yellow fever vaccination centre.

Approved manufacturers by WHO:

  • Aventis Pasteur (France)
  • BioManguinhos (Brazil)
  • Institut Pasteur Dakar (Senegal)

Dosing schedule: one single dose of 0.5ml subcutaneously; booster required every ten years.


  • infants <6 months old (risk of postvaccinal encephalitis)
  • thymic disease eg. thymoma, myasthenia gravis, previous thymectomy
  • hypersensitivity to raw eggs
  • precaution in pregnancy, breastfeeding, infants 6-9 months old, immunosuppressed or immunocompromised state

Adverse reactions

  1. Minor reactions: low-grade fever, myalgia
  2. Major reactions: encephalitis, autoimmune neurologic disease (Guillain-Barre syndrome, acute disseminated encephalo-myelitis) — estimated 0.5 per 100,000 doses

  3. Yellow fever vaccine-associated viscerotropic disease (fever, hypotension, respiratory failure, elevated hepatocellular enzymes, thrombocytopenia, lymphocytopenia) which is clinically and pathologically similar to fulminant yellow fever caused by wild-type virus, and may be fatal — about 0.3 to 0.5 per 100,000 doses distributed.



  1. CDC Travelers’ Health — Yellow Book 2008. Chap 4: Prevention of Specific Infectious Diseases: Yellow Fever [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; 2007 June 20. [updated 2009 Apr 17; cited 2009 Apr 22]. Available from:

  2. WHO | Yellow Fever (Fact Sheet No. 100) [Internet]. World Health Organisation [revised 2001 Dec; cited 2009 Apr 22]. Available from:

Posted April 22, 2009 by absinthemisia in yellow fever

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Malarone dosage adjustment in children   1 comment

1 paediatric Malarone tablet = 62.5mg atovaquone + 25mg proguanil HCl

Prophylaxis (in paeds tabs; dosing regime as for adults)
5-8kg: 1/2 tab daily
8-10kg: 3/4 tab daily
10-20kg: 1 tab daily
20-30kg: 2 tab daily
30-40kg: 3 tab daily
> 40kg: 1 adult tab daily

Posted April 20, 2009 by absinthemisia in malaria

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Malaria Endemic and Resistance Patterns of the World   1 comment

links below lead to the CDC public-access website, updated July 2011

Malaria endemicity:

for more detailed information by country, see Yellow Fever & Malaria Information by Country, CDC website.


Malaria resistance:
Most notably resistance of P. falciparum to chloroquine and mefloquine. Updated 10 Oct 2011.

  • Resistance to chloroquine: all areas except the Carribean, Central America west of the Panama Canal, and some countries in the Middle East.
  • Resistance to Fansidar: Amazon river basin of S. America, much of Southeast Asia and other parts of Asia, large parts of Africa.
  • Resistance to mefloquine: borders of Thailand with Myanmar and Cambodia, western provinces of Cambodia, eastern states of Myanmar, Myanmar-China border, along the Laos-Myanmar border and adjacent Thai-Cambodia border, and southern Vietnam. see Distribution of mefloquine-resistant malaria in Indochina

CDC Travelers’ Health — Yellow Book 2012. Chap 3: Infectious Diseases Related to Travel: Malaria [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; 2011 Jul 1. [updated 2011 Jul 1; cited 2011 Oct 10]. Available at: