Dazza, M.C.

Delaporte, E.

Froment, Alain

Henzel, D.

Larouzé, B.

Horizon / Pleins textes

Annals of Tropical Medicine and Parasitology, Vol. 88, No. 
1. 
c 
1, 97-98 (1994) 
Hepatitis C in remote populations of southern 
Cameroon 
The seroprevalences of hepatitis C virus 
(HCV) vary widely in Africa, as shown by 
studies of blood donors in capital cities: 
from 0.5% in Niger (Develoux et al., 1992) 
and 2.1% in Mozambique (Dazza et al., 1993) 
to 8.0% in Egypt (Kamel et al., 1992). The 
recent study of an open community from 
eastern Gabon indicated that this country 
might be highly endemic for HCV (Delaporte 
et al., 1993). These results prompted us to 
study, in neighbouring Cameroon, the preva- 
lence of HCV infection and the role of eth- 
nicity as a risk factor for HCV infection %I 
remote populations, including those of the 
pygmies considered to be the oldest inhabi- 
tants of Equatorial Africa (Froment et al., 
1993). 
In 1984, French and Cameroonian research- 
ers conducted a study called Food 1 4 n t h l - o p o l o ~ ~  
of Camevoonia.n Popiilntioiis in three Bantu- 
speaking populations of different origins, living 
in the same ecosystem and having different 
survival strategies (Froment et al., 1993). This 
survey was carried out in the Campo district, 
on the Atlantic Coast and on the border with 
Equatorial Guinea, and included a rain-forest 
game reserve. The study populations were the 
coastal Yassa, principally a fishing population, 
the Mvae agriculturalists and hunters and 
the Bakola pygmies, traditionally hunter- 
gatherers, scattered throughout the forest. The 
Bakola nowadays practise rudimentary agri- 
culture, but they also exchange game with 
neighbouring agriculturalists for staple foods 
(cassava, bananas) and manufactured goods. In 
the Campo district, the population density is 
only 1.3 people/km*. Most of the population is 
settled in ethnically homogeneous villages. 
Sera from a total of 277 subjects were col- 
lected in 1984 (mean age f S.D.=35*5 f 19.9 
years; ma1e:female sex ratio 0.82) comprising 
111 from the Yassa ethnic group, 80 from the 
Mvae group and 86 from the Bakola pygmy 
group. The mean ages ( 5 S.D.) of these groups 
were 32.5 f 22.4, 39.4 f 17.4 and 38-3 f 17.9 
0003-4983/94/010.09$+02 SOS.OO/O 
years, respectively [Kruskall-Wallis test 
(Kruskall and Wallis, 1952); H= 10-28, degrees 
of freedom (dJ)=2, P<0.006]. 
The stored sera were tested in 1993 for 
anti-HCV using a second-generation ELISA 
and, for confirmation, the Line Immuno Assay 
(Innogenetics, Antwerpen). Criteria for posi- 
tivity have been described elsewhere (Dazza et 
al., 1993). Age-adjusted prevalences were cal- 
culated using a direct method of adjustment, 
with pooled populations as reference. 
The overall prevalence of anti-HCV in sera 
collected in 1984 was ,4+1% [39/277; 95% 
confidence interval (C.I.): 10-0-18*2%] and 
was independent of sex (12.0943 in males 'u. 
15-8?/6 in females). Prevalence increased with 
age, from 1.5% (C.I.:O.9-4.6%) in the 0-19- 
years age range, and 17.9% (114-244%) in 
the 2049-years age range to 18.7% (10.5- 
26.9%) in those >49 years. The mean ages 
( f S.D.) of anti-HCV-positive and -negative 
subjects were 47.6 f 12.9 years and 
34-4 f 20-2 years, respectively (Guskall- 
Wallis test; H=16,99, df=l, P<4 x loT4). 
The age-adjusted anti-HCV prevalence 
(Table) was highest in the Mvae group (27.8% 
'u. 7.696 in the Yassa group and 8.4% in the 
Bakola group). Taking the Yassa group as 
reference, the relative risk of anti-HCV posi- 
tivity was 3.65 (C.I.:1*92-6.89) for the Mvae 
group and 1-10 (C.I.:0.32-3.62) for the Bakola 
group. 
This study shows the presence, in a remote 
area of southern Cameroon, of a highly en- 
demic HCV focus where ethnicity is a risk 
factor for infection. In studies performed in 
1988 in neighbouring Gabon, most anti- 
HCV-positive subjects were found to be 
viraemic (Delaporte et al., 1993). The present 
studies confirm the specificity of second gen- 
eration assays for the diagnosis of anti-HCV, 
even in stored African sera, and show that, 
in this region, there is a large HCV virus 
reservoir. Studies performed in industrialized 
countries indicate that HCV is, in most 
@j 1994 Liverpool School of Tropical Medicine 
ORSTOM Fonds Documentaire 
98 DEL=\PORTE E T  -AL. 
Positive 7 (S-4) 24 (22.2) S (7.2) 
Negative 104 (102.6) 56 (57.5) 78 (78.8) 
Values in parentheses are age-adjusted prevalences. using the pooled populations as 
reference. For the crude data, ,y2=2343, I&=?, P = 6 4  x 10- '. For the age-adjusted data, 
,y2=19.48, df=?, P=5.9 x IO-'. 
instances, transmitted parenterally (Reinus et 
d., 1992; Osmond et  nl., 19931, but many ORSTOhI, 
A. FROMENT 
questions remain. How does transmission hluseum Kational d'Histoire 
occur in this African focus, prgerentially 
affecting adults and certain ethnic groups? Do 
particular routes of transmission, such as France 
sexual intercourse, play a more important role 
Naturelle, 
9 1 SO8 Brunoy, 
in Africa than in Europe or the U.S.rZ.? Is 
the presence of anti-HCV a good indes of 
past exposure to HCV? FVhat is the clinical 
impact of HCV infection? The answers to 
these questions, derived from investigations 
of populations such as those studied here, 
will be of importance in designing prevention 
X I .  C. DAZZA 
D. HENZEL 
B. LAROUZE" 
INSERAI U 13 /IAlEA, 
190 Boulevard AlacDonald, 
75019 Paris, 
France 
strategies. 
E. DELAPORTE 
INSEFUT U1 3/IhIEA, R e c e i d  -37 Ortoher 1993, Reriseti 23 
190 Boulevard MacDonald, 
75019 Paris, *Author to whom correspondence should be 
France addressed. 
N o w n i b t y  1993, -4crepted 24 Noaember I993 
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Hepatitis C in remote populations of southern Cameroon

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