|
NAVRONGO HEALTH RESEARCH CENTRE A Field station of the Ministry of Health, Ghana (Member of the INDEPTH Network)
|
||||||||||
Location
:The
entire Kassena-Nankana district
Coordinator :Francis Anto
Investigators :Kojo Koram and Abraham Hodgson
Collaboration :Navrongo
Health Research centre, Ghana
Noguchi Memorial Institute for Medical Research, Ghana
Naval Medical Research Center, USA
Funding :US GOVERNMENT
Period Covered:May 2001 to November 2002
Size :6,900 Subjects
BACKGROUND OBJECTIVES METHODOLOGY RESULTS
The public health importance of malaria is immense as Plasmodium falciparum is estimated to be responsible for one to three million deaths of which over 75% are among African children each year. This report is on four prevalence surveys of malaria infection in the Kassena-Nankana district of northern Ghana aimed at providing background information that may be needed for the design and conduct of future field trials.
The primary objective of the study was to determine the age-specific parasite prevalence and anaemia in the KND.
All-age point prevalence surveys of malaria and anemia were conducted in the Kassena Nankana District (KND) of northern Ghana as an early step under a NIH (NIAID) contract to prepare Ghanaian laboratories and personnel for malaria vaccine trials. Prevalence surveys were undertaken to identify the age groups and locations most critically affected by malaria infection and anaemia. These surveys were timed to occur at the end of low (May) and high (November) malaria transmission seasons and to yield information as to the value of severe anemia (Hb <6.0 g/dL) as a possible marker of community health and/or vaccine effect. Important use was made of the Navrongo Demographic Surveillance System (NDSS), a progressing database that records births, deaths, movements, and health status of virtually the entire KND population (141,000).
The May 2001 dry season survey sampled 2,274 people, ranging from 1 month to 89 years of age. Infection by Plasmodium falciparum was found in 283 of the 1,004 males (28%) and in 231 of the 1,270 females (18%), a difference that may result from the preponderance of male children and female adults in the sample population. Malaria prevalence in children <15 years was 40% compared to 9% among adults. Less than 4% of babies under 6 months were parasitemic, but the prevalence of infection rose steadily above this age range and peaked at 54% among children of 5-10 years. Despite the high prevalence of infections among children, only 11% of cases were febrile and only 13 cases (1.3%) of severe anemia were found. Among young children of 6-24 months, considered most vulnerable to malaria and malaria-related anemia, those with parasitemia were significantly older (1.4 vs. 1.0 years; P < 0.0001) and had lower Hb levels (8.3 vs. 9.5 g/dL; P < 0.0001) than those without parasitemia. Boys and girls in this age group were similar in terms of proportions parasitemic, density of parasitemia, and ages infected.