Resistance of Plamodium falciparum to Antimalarial Drugs in Zaragoza (Antioquia, Colombia), 1998

Vol. 97(3): 401-406, April 2002

Silvia Blair-Trujillo⁺, Leidy Lacharme-Lora, Jaime Carmona-Fonseca

Grupo Malaria, Facultad de Medicina, Universidad de Antioquia, Carrera 51 D, No. 62-29, Medellín, Colombia

Plasmodium falciparum sensitivity to chloroquine (CHL), amodiaquine (AMO) and sulfadoxine/pyrimethamine (SDX/PYR) was assessed in vivo and in vitro in a representative sample from the population of Zaragoza in El Bajo Cauca region (Antioquia-Colombia). There were 94 patients with P. falciparum evaluated. For the in vivo test the patients were followed by clinical examination and microscopy, during 7 days. The in vitro test was performed following the recommendations of the World Health Organization. The in vivo prevalence of resistance to CHL was 67%, to AMO 3% and to SDX/PYR 9%. The in vitro test showed sensitivity to all antimalarials evaluated. Concordance for CHL between the in vivo and in vitro tests was 33%. For AMO and SDX/PYR, the concordance was 100%. We conclude that a high percentage of patients are resistant to CHL (in vivo). A high rate of intestinal parasitism might explain in part, the differences observed between the in vivo and the in vitro results. Therefore, new policies and treatment regimens should be proposed for the treatment of the infection in the region. Nationwide studies assessing the degree of resistance are needed.

Key words: Plasmodium falciparum - antimalarial drugs - resistance - Colombia

The first report of chloroquine (CHL) resistant Plasmodium falciparum was made in Colombia in 1961 (Moore & Lanier 1961). In the following years, other studies showed a high prevalence of resistance in many regions of the country (Walker & Lopez 1968). However, a detailed review of publications on resistance between 1961 and 1986 concluded that CHL resistance was only 19% (Blair 1986).

No additional studies were been made until recently when malaria incidence increased in all the country, with a parasite annual index (PAI) from 0.9 ‰ in 1967, to 10 ‰ in 1998 (Ministerio de Salud de Colombia 1999). Therefore, the issue of resistance to antimalarials has become more relevant. In a study carried out in Chocó (on the Pacific Coast of Colombia), resistance to CHL (47%) and sulphadoxine-pyrimethamine (SDX/PYR)(6%) was informed (Osorio et al. 1997). En Turbo, Uraba region, we found CHL resistance in 97%, amodiaquine (AMO) in 7% and SDX/PYR in 13%. A lower concordance was observed between in vivo and in vitro tests for CHL, but higher concordance for AMO and SDX/PYR (Blair et al. 2001). Turbo has an intermediate level of endemicity for malaria.

The present study evaluated the in vivo and in vitro sensitivity of P. falciparum to CHL, AMO and SDX/PYR in a representative sample taken from the population of Zaragoza (Bajo Cauca region), located in a highly endemic area for malaria and where the incidence of P. falciparum infection in 1998 was 90.6 ‰ inhabitants (Ministerio de Salud de Colombia 1998).

MATERIALS AND METHODS

RESULTS

DISCUSSION

ACKNOWLEDGEMENTS

To employees from the Hospital San Rafael in Zaragoza for their collaboration.

REFERENCES

Figure | Table I | Table II | Table III | Table IV | Table V | Table VI

This work was supported by Direccion Seccional de Salud de Antioquia and Universidad de Antioquia.

⁺Corresponding author. Fax: +574-2-633509. E-mail: sblair@catios.udea.edu.co

Received 12 July 2001

Accepted 9 October 2001