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Seasonality and shift in age-specific malaria prevalence and incidence in Binko and Carrière villages close to the lake in Selingué, Mali.

Touré M, Sanogo D, Dembele S, Diawara SI, Oppfeldt K, Schiøler KL, Haidara DB, Traoré SF, Alifrangis M, Konradsen F, Doumbia S - Malar. J. (2016)

Bottom Line: The number of clinical episodes per year was determined among the children in the cohort.Children 6-9 years old were at least twice more likely to carry parasites than children up to 5 years old.The peak incidence was observed between August and October (end of the rainy season), but the incidence remained high until December.

View Article: PubMed Central - PubMed

Affiliation: Malaria Research and Training Centre-Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, BP 1805, Mali.

ABSTRACT

Background: Malaria transmission in Mali is seasonal and peaks at the end of the rainy season in October. This study assessed the seasonal variations in the epidemiology of malaria among children under 10 years of age living in two villages in Selingué: Carrière, located along the Sankarani River but distant from the hydroelectric dam, and Binko, near irrigated rice fields, close to the dam. The aim of this study was to provide baseline data, seasonal pattern and age distribution of malaria incidence in two sites situated close to a lake in Selingué.

Methods: Geographically, Selingué area is located in the basin of Sakanrani and belongs to the district of Yanfolila in the third administrative region of Mali, Sikasso. Two cross-sectional surveys were conducted in October 2010 (end of transmission season) and in July 2011 (beginning of transmission season) to determine the point prevalence of asymptomatic parasitaemia, and anaemia among the children. Cumulative incidence of malaria per month was determined in a cohort of 549 children through active and passive case detection from November 2010 through October 2011. The number of clinical episodes per year was determined among the children in the cohort. Logistic regression was used to determine risk factors for malaria.

Results: The prevalence of malaria parasitaemia varied significantly between villages with a strong seasonality in Carrière (52.0-18.9 % in October 2010 and July 2011, respectively) compared with Binko (29.8-23.8 % in October 2010 and July 2011, respectively). Children 6-9 years old were at least twice more likely to carry parasites than children up to 5 years old. For malaria incidence, 64.8-71.9 % of all children experienced at least one episode of clinical malaria in Binko and Carrière, respectively. The peak incidence was observed between August and October (end of the rainy season), but the incidence remained high until December. Surprisingly, the risk of clinical malaria was two- to nine-fold higher among children 5-9 years old compared to younger children.

Conclusions: A shift in the peak of clinical episodes from children under 5-9 years of age calls for expanding control interventions, such as seasonal malaria chemoprophylaxis targeting the peak transmission months.

No MeSH data available.


Related in: MedlinePlus

Malaria Plasmodium falciparum density/µl among age groups in October 2010 a and July 2011 b for Binko and Carrière. Number P. falciparum/µl of blood was counted in infected children classified by age group and per village. Black represent density range from 1–1000 P. falciparum/µl Blue lighter represent density range from 1001–5000 P. falciparum/µl and White darker represent density range from 5000+ P. falciparum/µl. Blue bars represent Binko and red bars represent Carrière
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Fig2: Malaria Plasmodium falciparum density/µl among age groups in October 2010 a and July 2011 b for Binko and Carrière. Number P. falciparum/µl of blood was counted in infected children classified by age group and per village. Black represent density range from 1–1000 P. falciparum/µl Blue lighter represent density range from 1001–5000 P. falciparum/µl and White darker represent density range from 5000+ P. falciparum/µl. Blue bars represent Binko and red bars represent Carrière

Mentions: The parasite densities varied significantly between season and age groups. During the June survey, the proportion of high parasitaemia among infected children (density greater or equal to 5000 P. falciparum parasites/µl) was observed among children aged 1–4 years in Binko and children 5 years old and over in Carrière with respectively 8.3 and 9.5 %. Whereas during the October survey, respectively 43.6 and 69.2 % of infected children aged from 1–4 years in Binko and Carrière ranged from 1001–5000 P. falciparum parasites/µl while among infected children 5 and more years old, 62 % in Binko and 71.4 % in Carrière had a parasitaemia equal or greater than 5000 P. falciparum parasites/µl (Fig. 2a, b).Fig. 2


Seasonality and shift in age-specific malaria prevalence and incidence in Binko and Carrière villages close to the lake in Selingué, Mali.

Touré M, Sanogo D, Dembele S, Diawara SI, Oppfeldt K, Schiøler KL, Haidara DB, Traoré SF, Alifrangis M, Konradsen F, Doumbia S - Malar. J. (2016)

Malaria Plasmodium falciparum density/µl among age groups in October 2010 a and July 2011 b for Binko and Carrière. Number P. falciparum/µl of blood was counted in infected children classified by age group and per village. Black represent density range from 1–1000 P. falciparum/µl Blue lighter represent density range from 1001–5000 P. falciparum/µl and White darker represent density range from 5000+ P. falciparum/µl. Blue bars represent Binko and red bars represent Carrière
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4836195&req=5

Fig2: Malaria Plasmodium falciparum density/µl among age groups in October 2010 a and July 2011 b for Binko and Carrière. Number P. falciparum/µl of blood was counted in infected children classified by age group and per village. Black represent density range from 1–1000 P. falciparum/µl Blue lighter represent density range from 1001–5000 P. falciparum/µl and White darker represent density range from 5000+ P. falciparum/µl. Blue bars represent Binko and red bars represent Carrière
Mentions: The parasite densities varied significantly between season and age groups. During the June survey, the proportion of high parasitaemia among infected children (density greater or equal to 5000 P. falciparum parasites/µl) was observed among children aged 1–4 years in Binko and children 5 years old and over in Carrière with respectively 8.3 and 9.5 %. Whereas during the October survey, respectively 43.6 and 69.2 % of infected children aged from 1–4 years in Binko and Carrière ranged from 1001–5000 P. falciparum parasites/µl while among infected children 5 and more years old, 62 % in Binko and 71.4 % in Carrière had a parasitaemia equal or greater than 5000 P. falciparum parasites/µl (Fig. 2a, b).Fig. 2

Bottom Line: The number of clinical episodes per year was determined among the children in the cohort.Children 6-9 years old were at least twice more likely to carry parasites than children up to 5 years old.The peak incidence was observed between August and October (end of the rainy season), but the incidence remained high until December.

View Article: PubMed Central - PubMed

Affiliation: Malaria Research and Training Centre-Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, BP 1805, Mali.

ABSTRACT

Background: Malaria transmission in Mali is seasonal and peaks at the end of the rainy season in October. This study assessed the seasonal variations in the epidemiology of malaria among children under 10 years of age living in two villages in Selingué: Carrière, located along the Sankarani River but distant from the hydroelectric dam, and Binko, near irrigated rice fields, close to the dam. The aim of this study was to provide baseline data, seasonal pattern and age distribution of malaria incidence in two sites situated close to a lake in Selingué.

Methods: Geographically, Selingué area is located in the basin of Sakanrani and belongs to the district of Yanfolila in the third administrative region of Mali, Sikasso. Two cross-sectional surveys were conducted in October 2010 (end of transmission season) and in July 2011 (beginning of transmission season) to determine the point prevalence of asymptomatic parasitaemia, and anaemia among the children. Cumulative incidence of malaria per month was determined in a cohort of 549 children through active and passive case detection from November 2010 through October 2011. The number of clinical episodes per year was determined among the children in the cohort. Logistic regression was used to determine risk factors for malaria.

Results: The prevalence of malaria parasitaemia varied significantly between villages with a strong seasonality in Carrière (52.0-18.9 % in October 2010 and July 2011, respectively) compared with Binko (29.8-23.8 % in October 2010 and July 2011, respectively). Children 6-9 years old were at least twice more likely to carry parasites than children up to 5 years old. For malaria incidence, 64.8-71.9 % of all children experienced at least one episode of clinical malaria in Binko and Carrière, respectively. The peak incidence was observed between August and October (end of the rainy season), but the incidence remained high until December. Surprisingly, the risk of clinical malaria was two- to nine-fold higher among children 5-9 years old compared to younger children.

Conclusions: A shift in the peak of clinical episodes from children under 5-9 years of age calls for expanding control interventions, such as seasonal malaria chemoprophylaxis targeting the peak transmission months.

No MeSH data available.


Related in: MedlinePlus