371
nervous side effects such as dizziness and psychosis. It annears that these side effects, particularly the latter, are uncommon in children and are-dose-related(HELLGREN, 1990). The relative absence of these side effects in the more than 300 children tested with mefloquine in our hospital supports this assertion. A recent parallel study in our hosnital (L. A. Salako. unnublished observations) has shown’ high’levels of malaria antibodv titres in child: ren aged 5-12 years. This might have been responsible for the inabilitv to demonstrate in viva mefloauine failure in the group studied despite resistance in z&o. Therefore, the ultimate study correlating the results obtained in viva and in vitro will need to be done with low immunity children, i.e., those aged 0.5-2 years. In conclusion, the present studies have shown full sensitivity in vivo of falciparum malaria to mefloquine in Nigeria even in the presence of reduced susceptibility in vitro to some of the isolates. Acknowledgement
This study received support from the UNDPWorld Bank/WHO Special Programme for Research and Training in Tropical Diseases.
Hellgren, U. (1990). Drug concentration during antimalarial treatment and prophylaxis: relation to in-vivo outcome and in-vitro susceptibility. Thesis, Karolinska Institute, Stockholm, Sweden. Oduola, A. M. J., Milhous, W. K., Salako, L. A., Walker, 0. & Desjardins, R. E. (1987). Reduced in-vitro susceptibility to mefloquine in West African isolates of Plasmodiumfalciparum. Lancet, ii, 1304-1305.
Oduola, A. M. J., Moyou-Somo, R. S., Kyle, D. E., Martin, S. K., Gerena, L. & Milhous, W. K. (1989). Chloroquine resistant Plasmodium falciparum in indigenous residents of Cameroon. Transactions of the Royal Society of Tropical Medicine and Hygiene, 83,308-310. Rieckmann, K. H., Campbell, G. H., Sax, L. J. & Mrema, J. E. (1978). Drug sensitivity of Plasmodium falciparum: an invitro microtechnique. Lancet, i, 22-23. Ringwald, I’., Bartczak, S., Le Bras, J., Bricaire, F., Matheron, S., Bauchet, I. & Coulaud. I. (1990a). Failure of antimalarial prophylaxis’ with mefloquine ‘in Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene. 84.348-349.
Rin&ald, P.; Le Bras, J.? Voyer, C. &*Coulaud,- J. (1990b). Reduced in-vitro susceptibility to halofantrine of Plasmodium falciparum malaria in West Africa. Lancet, i, 421-422. Salako, L. A. & Aderounmu, A. F. (1987). In-vitro chloroquine and mefloquine resistant Plasmodium falciparum in Nigeria. Lancet, i, 572-573.
References
Aderounmu, A. F. & Fleckenstein, L. (1983). Pharmacokinetics of chloroquine diphosphate in the dog. Journal of Pharmacology and Experimental Therapeutics, 226,633-639.
Brasseur, I’., Kouamoua, J., Moyou, R. S. & Druilhe, I’. (1990). Emergence of mefloquine-resistant malaria in Africa without drug pressure. Lancet, ii, 59. Ekanem, 0. J., Wiesfeld, J. S., Salako, L. A., Nahlen, B. L., Ezedinachi, E. N. U., Walker, O., Breman, J. G., Laoye, 0. J. & Hedberg, K. (1990). In-vivo sensitivity of Plasmodium falciparum to chloroquine. Bulletin of the World Health Organization, 68,45-52.
Felix, P. R., Gay, F., Lyogoubi, A., Bustos, M. D. G., Diquet, B., Danis, M. & Gentilini, M. (1990). Resistancecroisee a la mefloquine et l’halofantrine lors d’un paludisme a falciparum contracte en Sierra Leone. Bulletin de la Societe de Pathologique Exotique, 83,43-45.
Gay, F., Binet, M. H., Bustos, M. D. G., Rouveix, B,, Danis, M., Roy, C. & Gentilini, M. (1990). Mefloquine failure in a child contracting falciparum malaria in West Africa. Lance& i, 1990-1991. Harinasuta, T., Bunnag, D. & Wernsdorfer, W. H. (1983). A chase II clinical trial of mefloouine in patients with chloroquine resistant falciparum malaria in Thailand. Bulletin of the World Health Organization, 61,229-305.
Salako. L. A.. Aiavi. F. 0.. Sowunmi. A. &Walker. 0. (19901. Malaria in &e&: a revisit. Annals of Tropical Medic&e and Parasitology, 84,435-445. Simon, F., Le Bras, J., Gaudebout, C. & Girard, P. M. (1988). Reduced sensitivity of Plasmodiumfalciparum to mefloquine in West Africa. Lancet. i. 467-468. Sowunmi, A., Salako, L. ‘A., Walker, 0. & Ogundahunsi, 9. A. T. (1990). Clinical effcacv of mefloauine in children suffering from chloroquine-resistant Plasmodium falciparum malaria in Nigeria. Transactions of the Royal Society of Tropical Medicine and Hygiene, 84,761-764.
WHO (1984). Advances in Malaria Chemotherapy. Geneva: World Health Organization, Technical Report Series, no. -9*, 111. WHO (1986). Severe and complicated malaria. Transactions of the Royal Society of Tropical Medicine and Hygiene, 80, supplement. WHO (1990). Severe and complicated malaria, second edition. Transactions of the Royal Society of Tropical Medicine and Hy-
giene,84, supplement 2. Received 12 August 1991; revised 27 September 1991; acceptedfor publication 4 October 1991
TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE (1992) 86, 371-372
Drug sensitivity studies during a highland malaria epidemic in Kenya Etfuzl, 1, i ‘Biomedical
EA. VtiO.K~~l$~, . . Sciences
ELdMS .
Research
Centre,
Kariukil, J, I. K. Martin3 Kenya Medical
Research Institute, P.O. Box 54840, Nairobj, Kenya; 2Division of Vector Borne Diseases, Nairoba, Kenya; 33C%SAAMRU-Kenya,P.O. Box 4021, APO NY 09675,
In 1990, following unusually heavy rains, a severemalaria epidemic occurred simultaneously in 3 highland areas of Kenya. The present study was carried out from
June to August 1990 to assessthe sensitivity of malaria parasites to 4 antimalarial drugs. The study sites were Health Centres at Soy, which was most affected by the epidemic. and at Turbo, which borders a malaria end&nic area. Both sites are 335 km north-west of Nairobi and 15 km from each other. Patients with uncomplicated malaria were recruited into the study if they had pure Plasmodium falciaarum infections. had a urine samnle negative for 4-aminoquinolines (LE~IJVELD & KORT~ANN, 1970) and for free sulpha (ALMEIDA-FILHO & SOUZA, 1983), and gave oral consent to participate in the study. The World Health Oreanization (WHO) 28 d in vivo test was carried out. The patients were sequentially assigned to treatment with chloroquine, amodiaquine, sulfadoxine-pyrimethamine, or sulfametopyrazme (sulfalene)/pyrimethamine at the recommended doses (WHO, 1973). Before drug treatment, blood was obtained for determining parasite sensitivity in vitro to chloroquine, amodiaquine, sulfadoxineipyrimethamine and quinine using the WHO mark II micro-tests (WHO,
372 Table. Sensitivities of Plasmodium falciparum isolates from Soy and Turbo, Kenya, to chloroquine, sulfadoxine/pyrimethamine, sulfametopyrazine (sulfalene)/pyrimethamine, and quinine
In vivo
C$mulative ;;. parasitarmic by $y Drug and site
No. of patients
Chloroquine SOY Turbo Amodiaquine SOY Turbo Sulfadoxineipyrimethamine SOY Turbo Sukt;etopyrazine/pyrimethamine Turbo Quinine SOY Turbo
14 9
i
7
9
10
1
1
1
;
1 0
:,
4 1
4 1
12 8
i
:
i
0 0
1
I
1
10 6 b
;:b
1
:,
amodiaquine,
In vitro
No. of isolates Sensitive Resistant
i
3 3
10
0
;
10
0
A
NDb NDb
:fzb
I
i:
:
b
-
_
“Of these 5,2 were resistant at the RI level, 2 at the RI1 level and 1 at the RI11 level. All other casesof resistanceof all the .drugs studied were at the RI level. bNot done. 1987). One hundred and sixty-nine of 489 patients (35%) screenedat Soy had P. falciparum infections (mean parasite count/$ of blood 26 445, standard deviation [SD]+31 432) compared to 60 of 313 (19%) screened at Turbo (mean parasite count/y1 of blood=15 914, ~~523 137). Forty-four patients met the selection criteria and were enrolled into the study at Soy (mean age= 18 years, SD&lS), whereas at Turbo there were 32 (mean age= 15 years, SD&14). Although, for the tests in vitro, results for days 7, 14, 21 and 28 are reported, parasitaemia at day 14 was chosen as indicative of drug effectiveness. Day 14 results can resolve the sensitive/RI question posed by the day 7 readings while avoiding the difficulty of distinguishing reinfection from recrudescenceat later follow-up dates in these areas of high transmission. In vitro, isolates were considered to be resistant if growth was seen at or above the following concentrations per well: 8 pmol, 4 pmol, 3000137.5pmol and 256 pmol for chloroquine, amodiaquine, sulfadoxineipyrimethamine and quinine respectively. At Soy, by day 14, the 2 sulphonamide combinations were significantly more effective than the 4-aminoquinolines (Fisher’s exact test, ZVO.003) and amodiaquine was more effective than chloroquine, though not significantly so (seeTable). At Turbo, only 119patients treated with chloroquine had parasitesby day 14; patients on the other 3 regimens completely cleared their parasitaemia. Thus all drugs were equally effective. All isolates tested in vitro were sensitive to sulfadoxineipyrimethamine and quinine (see Table). Resistanceto chloroquine and, to a lesser extent, amodiaquine was present. For both chloroquine and amodiaquine the resistance levels were higher in Soy. Even though the sample size was small, this study provided some indication of the relative efficacy of common antimalarial drugs used during an epidemic in Kenya.
The in vivo and in vitro data, taken together, permit ranking of the drugs in order of efficacy as chloroquine, amodiaquine and the suphonamide combinations. These results are in keeping with those most recently reported for Kenya (WATKINS et al., 1988). Clearly, drug sensitivities can vary considerably even in adjacent sites. Therefore, in epidemic situations drug sensitivity studies could serve as an important guide to therapy. If accessto such tests is lacking, patients should be treated with the most effective secondline antimalarial drug. Acknowledgments We acknowledge the support of Dr D. Koech, the Director,
KEMRI, Dr J. Oumaand Dr Some,and the technicalassist-
ance of Mr J. Mwangi, Mr S. Kaniaru and Mr J. Gachare. References Almeida-Filho, H. & Souza, J. M. A. (1983). A simple urine test for sulphonamides. Bulletin of the World Health Organization, 61,167-168. Lelijveld, J. & Kortmann, H. (1970). The eosin colour test of Dill and Glazko: a simple field test to detect chloroquine in urine. Bulletin of the World Health Organization, 42,477-479. Watkins, W. M., Percy, M., Crampton, J. M., Ward, S., Koech, D. & Howells, R. E. (1988). The changing response of Plasmodium falciparum to antimalarial drugs in East Africa. Transactions of rhe Royal Society of Tropical Medicine and Hygiene, 82,21-26. Who (1973). Chemotherapy of Malaria and Drug Resistance to Andmalarials. Geneva: World Health Organization, Technical Report Series, no. 529. WHO (1987). In vitro micro-test (mark II) for the assessmentof the response of Plasmodium falciparum to chloroquine, mefloquine, quinine, sulfadoxinelpyrimethamine and amodiaquine. Geneva: World Health Organization, mimeographed document no. MAP187.2.
Received 17 June 1991; revised 16 October 1991; accepted for publication 16 October 1991
nervous side effects such as dizziness and psychosis. It annears that these side effects, particularly the latter, are uncommon in children and are-dose-related(HELLGREN, 1990). The relative absence of these side effects in the more than 300 children tested with mefloquine in our hospital supports this assertion. A recent parallel study in our hosnital (L. A. Salako. unnublished observations) has shown’ high’levels of malaria antibodv titres in child: ren aged 5-12 years. This might have been responsible for the inabilitv to demonstrate in viva mefloauine failure in the group studied despite resistance in z&o. Therefore, the ultimate study correlating the results obtained in viva and in vitro will need to be done with low immunity children, i.e., those aged 0.5-2 years. In conclusion, the present studies have shown full sensitivity in vivo of falciparum malaria to mefloquine in Nigeria even in the presence of reduced susceptibility in vitro to some of the isolates. Acknowledgement
This study received support from the UNDPWorld Bank/WHO Special Programme for Research and Training in Tropical Diseases.
Hellgren, U. (1990). Drug concentration during antimalarial treatment and prophylaxis: relation to in-vivo outcome and in-vitro susceptibility. Thesis, Karolinska Institute, Stockholm, Sweden. Oduola, A. M. J., Milhous, W. K., Salako, L. A., Walker, 0. & Desjardins, R. E. (1987). Reduced in-vitro susceptibility to mefloquine in West African isolates of Plasmodiumfalciparum. Lancet, ii, 1304-1305.
Oduola, A. M. J., Moyou-Somo, R. S., Kyle, D. E., Martin, S. K., Gerena, L. & Milhous, W. K. (1989). Chloroquine resistant Plasmodium falciparum in indigenous residents of Cameroon. Transactions of the Royal Society of Tropical Medicine and Hygiene, 83,308-310. Rieckmann, K. H., Campbell, G. H., Sax, L. J. & Mrema, J. E. (1978). Drug sensitivity of Plasmodium falciparum: an invitro microtechnique. Lancet, i, 22-23. Ringwald, I’., Bartczak, S., Le Bras, J., Bricaire, F., Matheron, S., Bauchet, I. & Coulaud. I. (1990a). Failure of antimalarial prophylaxis’ with mefloquine ‘in Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene. 84.348-349.
Rin&ald, P.; Le Bras, J.? Voyer, C. &*Coulaud,- J. (1990b). Reduced in-vitro susceptibility to halofantrine of Plasmodium falciparum malaria in West Africa. Lancet, i, 421-422. Salako, L. A. & Aderounmu, A. F. (1987). In-vitro chloroquine and mefloquine resistant Plasmodium falciparum in Nigeria. Lancet, i, 572-573.
References
Aderounmu, A. F. & Fleckenstein, L. (1983). Pharmacokinetics of chloroquine diphosphate in the dog. Journal of Pharmacology and Experimental Therapeutics, 226,633-639.
Brasseur, I’., Kouamoua, J., Moyou, R. S. & Druilhe, I’. (1990). Emergence of mefloquine-resistant malaria in Africa without drug pressure. Lancet, ii, 59. Ekanem, 0. J., Wiesfeld, J. S., Salako, L. A., Nahlen, B. L., Ezedinachi, E. N. U., Walker, O., Breman, J. G., Laoye, 0. J. & Hedberg, K. (1990). In-vivo sensitivity of Plasmodium falciparum to chloroquine. Bulletin of the World Health Organization, 68,45-52.
Felix, P. R., Gay, F., Lyogoubi, A., Bustos, M. D. G., Diquet, B., Danis, M. & Gentilini, M. (1990). Resistancecroisee a la mefloquine et l’halofantrine lors d’un paludisme a falciparum contracte en Sierra Leone. Bulletin de la Societe de Pathologique Exotique, 83,43-45.
Gay, F., Binet, M. H., Bustos, M. D. G., Rouveix, B,, Danis, M., Roy, C. & Gentilini, M. (1990). Mefloquine failure in a child contracting falciparum malaria in West Africa. Lance& i, 1990-1991. Harinasuta, T., Bunnag, D. & Wernsdorfer, W. H. (1983). A chase II clinical trial of mefloouine in patients with chloroquine resistant falciparum malaria in Thailand. Bulletin of the World Health Organization, 61,229-305.
Salako. L. A.. Aiavi. F. 0.. Sowunmi. A. &Walker. 0. (19901. Malaria in &e&: a revisit. Annals of Tropical Medic&e and Parasitology, 84,435-445. Simon, F., Le Bras, J., Gaudebout, C. & Girard, P. M. (1988). Reduced sensitivity of Plasmodiumfalciparum to mefloquine in West Africa. Lancet. i. 467-468. Sowunmi, A., Salako, L. ‘A., Walker, 0. & Ogundahunsi, 9. A. T. (1990). Clinical effcacv of mefloauine in children suffering from chloroquine-resistant Plasmodium falciparum malaria in Nigeria. Transactions of the Royal Society of Tropical Medicine and Hygiene, 84,761-764.
WHO (1984). Advances in Malaria Chemotherapy. Geneva: World Health Organization, Technical Report Series, no. -9*, 111. WHO (1986). Severe and complicated malaria. Transactions of the Royal Society of Tropical Medicine and Hygiene, 80, supplement. WHO (1990). Severe and complicated malaria, second edition. Transactions of the Royal Society of Tropical Medicine and Hy-
giene,84, supplement 2. Received 12 August 1991; revised 27 September 1991; acceptedfor publication 4 October 1991
TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE (1992) 86, 371-372
Drug sensitivity studies during a highland malaria epidemic in Kenya Etfuzl, 1, i ‘Biomedical
EA. VtiO.K~~l$~, . . Sciences
ELdMS .
Research
Centre,
Kariukil, J, I. K. Martin3 Kenya Medical
Research Institute, P.O. Box 54840, Nairobj, Kenya; 2Division of Vector Borne Diseases, Nairoba, Kenya; 33C%SAAMRU-Kenya,P.O. Box 4021, APO NY 09675,
In 1990, following unusually heavy rains, a severemalaria epidemic occurred simultaneously in 3 highland areas of Kenya. The present study was carried out from
June to August 1990 to assessthe sensitivity of malaria parasites to 4 antimalarial drugs. The study sites were Health Centres at Soy, which was most affected by the epidemic. and at Turbo, which borders a malaria end&nic area. Both sites are 335 km north-west of Nairobi and 15 km from each other. Patients with uncomplicated malaria were recruited into the study if they had pure Plasmodium falciaarum infections. had a urine samnle negative for 4-aminoquinolines (LE~IJVELD & KORT~ANN, 1970) and for free sulpha (ALMEIDA-FILHO & SOUZA, 1983), and gave oral consent to participate in the study. The World Health Oreanization (WHO) 28 d in vivo test was carried out. The patients were sequentially assigned to treatment with chloroquine, amodiaquine, sulfadoxine-pyrimethamine, or sulfametopyrazme (sulfalene)/pyrimethamine at the recommended doses (WHO, 1973). Before drug treatment, blood was obtained for determining parasite sensitivity in vitro to chloroquine, amodiaquine, sulfadoxineipyrimethamine and quinine using the WHO mark II micro-tests (WHO,
372 Table. Sensitivities of Plasmodium falciparum isolates from Soy and Turbo, Kenya, to chloroquine, sulfadoxine/pyrimethamine, sulfametopyrazine (sulfalene)/pyrimethamine, and quinine
In vivo
C$mulative ;;. parasitarmic by $y Drug and site
No. of patients
Chloroquine SOY Turbo Amodiaquine SOY Turbo Sulfadoxineipyrimethamine SOY Turbo Sukt;etopyrazine/pyrimethamine Turbo Quinine SOY Turbo
14 9
i
7
9
10
1
1
1
;
1 0
:,
4 1
4 1
12 8
i
:
i
0 0
1
I
1
10 6 b
;:b
1
:,
amodiaquine,
In vitro
No. of isolates Sensitive Resistant
i
3 3
10
0
;
10
0
A
NDb NDb
:fzb
I
i:
:
b
-
_
“Of these 5,2 were resistant at the RI level, 2 at the RI1 level and 1 at the RI11 level. All other casesof resistanceof all the .drugs studied were at the RI level. bNot done. 1987). One hundred and sixty-nine of 489 patients (35%) screenedat Soy had P. falciparum infections (mean parasite count/$ of blood 26 445, standard deviation [SD]+31 432) compared to 60 of 313 (19%) screened at Turbo (mean parasite count/y1 of blood=15 914, ~~523 137). Forty-four patients met the selection criteria and were enrolled into the study at Soy (mean age= 18 years, SD&lS), whereas at Turbo there were 32 (mean age= 15 years, SD&14). Although, for the tests in vitro, results for days 7, 14, 21 and 28 are reported, parasitaemia at day 14 was chosen as indicative of drug effectiveness. Day 14 results can resolve the sensitive/RI question posed by the day 7 readings while avoiding the difficulty of distinguishing reinfection from recrudescenceat later follow-up dates in these areas of high transmission. In vitro, isolates were considered to be resistant if growth was seen at or above the following concentrations per well: 8 pmol, 4 pmol, 3000137.5pmol and 256 pmol for chloroquine, amodiaquine, sulfadoxineipyrimethamine and quinine respectively. At Soy, by day 14, the 2 sulphonamide combinations were significantly more effective than the 4-aminoquinolines (Fisher’s exact test, ZVO.003) and amodiaquine was more effective than chloroquine, though not significantly so (seeTable). At Turbo, only 119patients treated with chloroquine had parasitesby day 14; patients on the other 3 regimens completely cleared their parasitaemia. Thus all drugs were equally effective. All isolates tested in vitro were sensitive to sulfadoxineipyrimethamine and quinine (see Table). Resistanceto chloroquine and, to a lesser extent, amodiaquine was present. For both chloroquine and amodiaquine the resistance levels were higher in Soy. Even though the sample size was small, this study provided some indication of the relative efficacy of common antimalarial drugs used during an epidemic in Kenya.
The in vivo and in vitro data, taken together, permit ranking of the drugs in order of efficacy as chloroquine, amodiaquine and the suphonamide combinations. These results are in keeping with those most recently reported for Kenya (WATKINS et al., 1988). Clearly, drug sensitivities can vary considerably even in adjacent sites. Therefore, in epidemic situations drug sensitivity studies could serve as an important guide to therapy. If accessto such tests is lacking, patients should be treated with the most effective secondline antimalarial drug. Acknowledgments We acknowledge the support of Dr D. Koech, the Director,
KEMRI, Dr J. Oumaand Dr Some,and the technicalassist-
ance of Mr J. Mwangi, Mr S. Kaniaru and Mr J. Gachare. References Almeida-Filho, H. & Souza, J. M. A. (1983). A simple urine test for sulphonamides. Bulletin of the World Health Organization, 61,167-168. Lelijveld, J. & Kortmann, H. (1970). The eosin colour test of Dill and Glazko: a simple field test to detect chloroquine in urine. Bulletin of the World Health Organization, 42,477-479. Watkins, W. M., Percy, M., Crampton, J. M., Ward, S., Koech, D. & Howells, R. E. (1988). The changing response of Plasmodium falciparum to antimalarial drugs in East Africa. Transactions of rhe Royal Society of Tropical Medicine and Hygiene, 82,21-26. Who (1973). Chemotherapy of Malaria and Drug Resistance to Andmalarials. Geneva: World Health Organization, Technical Report Series, no. 529. WHO (1987). In vitro micro-test (mark II) for the assessmentof the response of Plasmodium falciparum to chloroquine, mefloquine, quinine, sulfadoxinelpyrimethamine and amodiaquine. Geneva: World Health Organization, mimeographed document no. MAP187.2.
Received 17 June 1991; revised 16 October 1991; accepted for publication 16 October 1991
