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[08/03/2005]
 Liberia | |
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Dr Francis Louis, Yaoundé, Cameroon
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General Statistics
Area: 96,320
km²
Population:
2,800,000 inhabitants
Capital:
Monrovia
Currency:
Liberian dollar Official
Language: English
Bordering
Countries: Sierra Leone, Guinea, Ivory Coast 
Out of 192 countries Liberia ranks147th for life
expectancy, 182nd for infant mortality, 125th
for GNP, 188th for daily calorie intake,
169th for literacy, 169th for the percentage
of children in full-time education (source: Atlas Encyclopédique
Mondial, Nathan Ed., Paris 1996, pp.358-359).
The temperature is virtually the same all year long, between 22°C
and 30°C. There are two well defined seasons: the humid season that
runs from May to October, and the dry season that runs from October
to March during which a dust laden wind blows called the
“harmattan”. | Epidemiological facies
According to Mouchet et al’s classification Malaria in this country
is stable and equatorial: transmission by anopheles is both intense
and permanent and can reach up to 1,000 infectious bites (female
anopheles carriers of sporozoites) per person per year. This
accounts for the early relative immunity that is acquired at around
the age of 5. 30% to 50% of childhood fevers are malaria linked.
Morbidity is present all year long. Serious forms of the disease,
in particular pernicious malaria, are often seen in young children
but rarely in adults due to their immunity (38).
The country was classified as a holo-endemic zone as of 1935: the
examination of 656 children gave a spleen rate of 64% (2).
Three parasite species are present: Plasmodiumfalciparum
(82%), Plasmodiummalariae (39%)
and Plasmodiumovale (9%) (12).
| Vectors
Few studies on anopheles have been carried out in the country. In
1985 at Yekepa, Björkman announced occurrences of 45% for Anopheles funestus, 37%
for Anopheles
hancocki and 18% for Anopheles gambiae
(12).
Jacques Brunhes et al.(Les anophèles de la région afro-tropicale,
logiciel ORSTOM Ed., 1998) registered 16 diffrerent
species of anopheles in the country: Anopheles barberellus,
Anopheles cinctus, Anopheles funestus, Anopheles gambiae, Anopheles
hancocki, Anopheles hargreavesi, Anopheles melas, Anopheles nili,
Anopheles obscurus, Anopheles paludis, Anopheles pretoriensis,
Anopheles rhodesiensis rhodesiensis, Anopheles smithii, Anopheles
squamosus, Anopheles wellcomei wellcomei and Anopheles ziemanni.
| Chemoresistance
1. Resistance to
chloroquine: A first in vivo study conducted in 1985, on 53 children aged
between 1 and 12 years old, and in vitro on 26 isolates did not
show any chloroquine-resistance (12). A second in vivo study on 62
children in 1986 gave the same results (12). In 1987-1988, the rate
of parasite persistence after a cure with chloroquine was at 28%
(54 out of 190 patients)(25). 2. Resistance to
other antimalarial drugs: In 1986, no resistance was found in vivo or in vitro to the
sulfadoxine-pyrimethamine combination. (12). In 1987-1988, 7 out of 23 patients resistant to chloroquine were
also resistant to the sulfadoxine-pyrimethamine combination (30%)
and 1 patient out of 29 (3%) could not be cured with quinine
(25 ). In 1990, the effectiveness of quinine was confirmed with a
dosage of 10 mg/kg twice a day for a 3 days treatment
(12 ). | The National Anti Malaria Program
There have been virtually no publications on anti malaria action in
Liberia.
Y. Kassankogno noted that between1996-1997 a program was set up to
train 80 people in the handling of serious malaria but this had no
concrete results. He also mentions a program for the management of
cases and the use of treated mosquito nets but without any further
precision.(48).
| Research Institutions
Most publications concern the region of Yepeka, in the north east
of the country, as it is the headquarters for the Yepeka Clinical
Research and Training Unit, Liberia Institute of Biomedical
Research. This institution has developed an active collaboration
plan with the “Department of Infectious Diseases”, Karolinska
Institute, Stockholm, Sweden.
| Advice to travelers
According to the B.E.H. n°24-25 of the 14th June 2005, Liberia
is classified in chloroquine-resistance group III . This signifies
that a traveler spending less than 3 months in the country should
take the Mefloquine or the Atovaquone-Proguanil combined
treatment. Individual measures of protection against insect bites should
not be forgotten: insect repellant skin creams, insecticide
diffusers, mosquito nets treated with a long lasting
insecticide. | Bibliography
1. KINGSTON M.E. - Experience with urea in invert sugar for the
treatment of cerebral malaria. J. Trop. Med. Hyg. 1971 ; 74:
249-252.
2. ANIGSTEIN L. - Sunny days among black people: the diary of an
expedition into the Liberian jungle, 1935. Texas Rep. Biol. Med.
1972 ; 30: 249-275.
3. WINTROB R.M. - Malaria and the acute psychotic episode. J. Nerv.
Mental Dis. 1973 ; 156: 306-317.
4. VOLLER A. - Applications of immunofluorescence to the
seroepidemiology of malaria. Ann. N Y Acad. Sci. 1975 ; 254:
326-330.
5. WILLCOX M.C., BECKMAN L. - Haemoglobin variants,
beta-thalassaemia and G-6-PD types in Liberia. Hum. Hered. 1981 ;
31: 339-347.
6. JEPSEN S. - Inhibition of in vitro growth of Plasmodiumfalciparum by purified
antimalarial human IgG antibodies. Scand. J. Immunol. 1983 ; 18:
567-571.
7. SORENSEN P.G., MICKLEY H., SCHMIDT K.G. - Malaria-induced immune
thrombocytopenia. Vox Sang. 1984 ; 47: 68-72.
8. SCHAPIRA A., FOGH S., JEPSEN S. et Coll. - Detection of
antibodies to malaria: comparison of results with ELISA, IFAT, and
crossed immunoelectrophoresis. Acta Path. Microbiol. Immunol.
Scand. Sect. B 1984 ; 92: 299-304.
9. PERLMANN H., BERZINS K., WAHLGREN M. et Coll. - Antibodies in
malarial sera to parasite antigens in the membrane of erythrocytes
infected with early asexual stages of Plasmodiumfalciparum. J. Exp. Med.
1984 ; 159: 1686-1704.
10. WILLCOX M.C., BJORKMAN A., BROHULT J. - The effect of
persistent malarial infections on haemoglobin A2 levels Liberian
children. Trans. R. Soc. Trop. Med. Hyg. 1985 ; 79:
242-244. 11. BJORKMAN A., HEDMAN P., BROHULT J. et Coll. - Different
malaria control activities in an area of Liberia. Effects on
malariometric parameters. Ann. Trop. Med.
Parasitol. 1985 ; 79: 239-246.
12. BJORKMAN A., BROHULT J., WILLCOX M. et Coll. - Malaria control
by chlorproguanil. I. Clinical effects susceptibility
of Plasmodiumfalciparum in vivo after
seven years of monthly chlorproguanil administration to children in
a Liberian village. Ann. Trop. Med.
Parasitol. 1985 ; 6: 597-601.
13. BJORKMAN A., ROMBO L., HETLAND G. et Coll. - Susceptibility
of Plasmodium falciparum
to chloroquine in Northern Liberia after 20 years of
chemosuppression and therapy. Ann. Trop. Med.
Parasitol. 1985 ; 79: 603-606.
14. BJORKMAN A. - Susceptibility of Plasmodiumfalciparum to chloroquine
in Liberia, West Africa: in vitro tests for 24 and 48 hours. Scand.
J. Infect. Dis. 1986 ; 18: 167-171.
15. WAHLGREN M., BJORKMAN A., PERLMANN H. et Coll. - Anti-Plasmodiumfalciparum antibodies
acquired by residents in a holoendemic area of Liberia during
development of clinical immunity. Am. J. Trop. Med. Hyg.
1986 ; 35: 22-29.
16. BJORKMAN A., WILLCOX M. - In vivo and in vitro susceptibility
of Plasmodium falciparum
to sulphadoxine/pyrimethamine in Liberia, West Africa. Trans.
R. Soc. Trop. Med. Hyg. 1986 ; 80:
572-574.
17. MILLER M.J. - Malaria morbidity in West Africa. Trans. R.
Soc. Trop. Med. Hyg. 1986 ; 80: 347-348.
18. BJORKMAN A., HOLMBERG M., LEBBAD M. et Coll. - Application in
clinical epidemiology of new advances in immunology and molecular
biology of malaria. Parassitologia 1986 ; 28: 95-99.
19. BJORKMAN A., ROMBO L., WILLCOX M. - In vivo response
of Plasmodium falciparum
to different doses of chloroquine in semi-immune children in
Liberia, West Africa. Ann. Trop. Med.
Parasitol. 1986 ; 80: 1-6.
20. BJORKMAN A., BROHULT J., PEHRSON P.O. et Coll. - Monthly
antimalarial chemotherapy to children in a holoendemic area of
Liberia. Ann. Trop. Med. Parasitol. 1986 ; 80:
155-167. 21. FINE E., INSELBURG J., OBEING J., HANSON A. - Plasmodiumfalciparum-inhibitory
monoclonal antibodies produced by human hybridomas. Parasite
Immunol. 1987 ; 9: 305-320.
22. PERLMANN H., PERLMANN P., BERZINS K. et Coll. - Dissection of
the human antibody response to the malaria antigen Pf155/RESA into
epitope specific components. Immunol. Rev. 1989 ; 112:
115-132.
23. HOLLINGDALE M.R., HOGH B., PETERSEN E. et Coll. - Age-dependent
occurence of protective anti-Plasmodiumfalciparum sporozoite
antibodies in a holoendemic area of Liberia. Trans. R.
Soc. Trop. Med. Hyg. 1989 ; 83: 322-324.
24. PETERSEN E., HOGH B., PERLMANN H. et Coll. - An epidemiological
study of humoral and cell-mediated immune response to
the Plasmodiumfalciparum antigen
Pf155/RESA in adult Liberians. Am. J. Trop. Med. Hyg. 1989 ;
41: 386-394.
25. MONSON M.H., KYLE D.E., ODUOLA A.M.J. - Multiple drug
resistance of Plasmodiumfalciparum in
Liberia. Trans. R. Soc. Trop. Med. Hyg. 1989 ; 83:
311-312.
26. BJORKMANN A., PERLMANN H., PETERSEN E. et Coll. - Consecutive
determination of seroactivities to Pf155/RESA antigen and to its
different repetitive sequences in adult men from a holoendemic area
of Liberia. Parasite Immunol. 1990 ; 12: 115-123.
27. PETERSEN E., HOGH B., MARBIAH N.T. et Coll. - A longitudinal
study of antibodies to the Plasmodium falciparum
antigen Pf155/RESA and immunity to malaria infection in adult
Liberians. Trans. R. Soc. Trop. Med. Hyg. 1990 ; 84:
339-345.
28. BERZINS K., PERLMANN H., WAHLIN B. et Coll. - Passive
immunization of Aotus monkeys with human antibodies to
the Plasmodiumfalciparum antigen
Pf155/RESA. Infect. Immun. 1991 ; 59: 1500-1506.
29. PETERSEN E., HOGH B., MARBIAH N.T. et Coll. - Development of
immunity against Plasmodium falciparum
malaria: clinical and parasitologic immunity cannot be separated.
J. Indect. Dis. 1991 ; 164: 949-953.
30. PETERSEN E., HOGH B., MARBIAH N.T. et Coll. - Clinical and
parasitological studies on malaria in Liberian adults living under
intense malaria transmission. Ann. Trop. Med.
Parasitol. 1991 ; 85: 577-584. 31. TROYE-BLOMBERG M., OLERUP O., LARSSON A. et Coll. - Failure
to detect MHC class II associations of the human immune response
induced by repeated malaria infections to the Plasmodiumfalciparum antigen
Pf155/RESA. Int. Immunol. 1991 ; 3: 1043-1051.
32. BJORKMAN A., WILLCOX M., MARBIAH N., PAYNE D. - Susceptibility
of Plasmodiumfalciparum to different
doses of quinine in vivo and to quinine and quinidine in vitro in
relation to chloroquine in Liberia. Bull. WHO 1991 ; 69:
459-465.
33. BJORKMAN A., LEBBAD M., PERLMANN H. et Coll. - Longitudinal
study of seroreactivities to Pf155//RESA and its repetitive
sequences in small children from a holoendemic area of Liberia.
Parasite Immunol. 1991 ; 13: 301-311.
34. HOGH B., MARBIAH N.T., PETERSEN E. et Coll. - A longitudinal
study of seroreactivities to Plasmodium falciparum
antigens in infants and children living in a holoendemic area of
Liberia. Am. J. Trop. Med. Hyg. 1991 ; 44: 191-200.
35. KUN J., HESSELBACH J., SCHREIBER M. et Coll. - Cloning and
expression of genomic DNA sequences coding for putative erythrocyte
membrane-associated antigens of Plasmodiumfalciparum. Res. Immunol.
1991 ; 142: 199-210.
36. SJOBERG K., LEPERS J-P., RAHARIMALALA L. - Genetic regulation
of human anti-malarial antibodies in twins. Proc. Natl. Acad. Sci.
USA 1992 ; 89: 2101-2104.
37. HOGH B., PETERSEN E., DZIEGEL M. et Coll. - Antibodies to a
recombinant glutamate-rich Plasmodiumfalciparum protein:
evidence for protection of individuals living in a holoendemic area
of Liberia. Am. J. Trop. Med. Hyg. 1992 ; 46:
307-313.
38. MOUCHET J., CARNEVALE P., COOSEMANS M. et Coll. - Typologie du
paludisme en Afrique. Santé 1993 ; 3:
220-238.
39. IQBAL J., PERLMANN P., GREENWOOD B.M. et Coll. - Seroreactivity
with the Plasmodiumfalciparum blood stage
antigen Pf332 in adults and children from malaria-endemic regions.
Clin. Exp. Immunol. 1993 ; 94: 68-74.
40. BECKER S.R., THORNTON J.N., HOLDER W. - Infant and child
mortality estimates in two counties of Liberia: 1984. Int. J.
Epidemiol. 1993 ; 22: S42-S49.
41. FOSTER S.O., SPIEGEL R.A., MOKDAD A. et Coll. - Immunization,
oral rehydratation therapy and malaria chemotherapy among children
under 5 in Bomi and Grand Cape Mount Counties, 1984 and 1988.
Int. J. Epidemiol. 1993 ; 22: S50-S55.
42. HOGH B., MARBIAH N.T., PETERSEN E. et Coll. - Classification of
clinical falciparum malaria and its use for the evaluation of
chemosuppression in children under six years of age in Liberia,
West Africa. Acta Tropica 1993 ; 54: 105-115.
43. HOGH B., PETERSEN E., CRANDALL I. et Coll. - Immune responses
to band 3 neoantigens on Plasmodiumfalciparum-infected
erythrocytes in subjects living in an area of intense malaria
transmission are associated with low parasite density and high
hematocrit value. Infect. Immun. 1994 ; 62: 4362-4366.
44. GOTTSCHAU A., HOGH B. - Interval censored survival data and
multistate compartmental models in the analysis of first appearence
of Plasmodium falciparum
parasites in infants. Stat. Med. 1995 ; 14: 2727-2736.
45. HOGH B., MARBIAH N.T., BURGHAUS P.A., ANDERSEN P.K. -
Relationship between maternally derived anti-Plasmodiumfalciparum antibodies and
risk of infection and disease in infants living in an area of
Liberia, West Africa, in which malaria is highly endemic. Infect.
Immun. 1995 ; 63: 4034-4038.
46. SIDDIQUE A.B., AHLBORG N., WARSAME M. et Coll. - Antibodies to
a non-repeat region of Plasmodiumfalciparum antigen
Pf155/RESA in individuals from malaria-endemic areas. Clin. Exp.
Immunol. 1999 ; 116: 493-499.
47. DURAND R., DI POIAZZA J.P., LONGUET C. et Coll. - Increased
incidence of cycloguanil resistance in malaria cases entering
France from Africa, determined as point mutations in the
parasites'dihydrofolate-reductase genes. Ann. Trop. Med.
Parasitol. 1999 ; 93: 25-30.
48. KASSANKOGNO Y. - Aperçu sur le programme de lutte contre le
paludisme africain pour la période 1996-1997. Malaria and
Infectious Diseases in Africa 1999 ; n°9 bis: 52-61.
49. VIRARAGHAVAN R., JANTAUSCH B. - Congenital malaria: diagnosis
and therapy. Clin. Pediatr. 2000 ; 39: 66-67.
50. WORLEY C.W., WORLEY K.A., KUMAR P.L. - Infectious disease
challenges in immigrants from tropical countries. Pediatrics 2000 ;
106: E3. |
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