Longitudinal survey of malaria morbidity over 10 years in Saharevo (Madagascar): further lessons for strengthening malaria control

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Madagascar has been known for having bio-geo-ecological diversity which is reflected by a complex malaria epidemiology ranging from hyperendemic to malaria-free areas. Malaria-related attacks and infection are frequently recorded both in children and adults living in areas of low malaria transmission. To integrate this variability in the national malaria control policy, extensive epidemiological studies are required to up-date previous records and adjust strategies. Methods A longitudinal malaria survey was conducted from July 1996 to June 2005 among an average cohort of 214 villagers in Saharevo, located at 900 m above the sea. Saharevo is a typical eastern foothill site at the junction between a costal wet tropical area (equatorial malaria pattern) and a drier high-altitude area (low malaria transmission). Results Passive and active malaria detection revealed that malaria transmission in Saharevo follows an abrupt seasonal variation. Interestingly, malaria was confirmed in 45% (1,271/2,794) of malaria-presumed fevers seen at the health centre. All four Plasmodia that infect humans were also found: Plasmodium falciparum ; Plasmodium vivax , Plasmodium malariae and Plasmodium ovale . Half of the malaria-presumed fevers could be confirmed over the season with the highest malaria transmission level, although less than a quarter in lower transmission time, highlighting the importance of diagnosis prior to treatment intake. P. falciparum malaria has been predominant (98%). The high prevalence of P. falciparum malaria affects more particularly under 10 years old children in both symptomatic and asymptomatic contexts. Children between two and four years of age experienced an average of 2.6 malaria attacks with P. falciparum per annum. Moreover, estimated incidence of P. falciparum malaria tends to show that half of the attacks (15 attacks) risk to occur during the first 10 years of life for a 60-year-old adult who would have experienced 32 malaria attacks. Conclusion The incidence of malaria decreased slightly with age but remained important among children and adults in Saharevo. .

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• Published by: biomed
• Published: 01 January 2009
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• Language: English

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Malaria Journal

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Open Access Research Longitudinal survey of malaria morbidity over 10 years in Saharevo (Madagascar): further lessons for strengthening malaria control †1,2 †1 Léon P Rabarijaona , Milijaona Randrianarivelojosia* , 1,3 1 1 Lucie A Raharimalala , Arsène Ratsimbasoa , Arthur Randriamanantena , 1 1,4 1 Laurence Randrianasolo , Lanto A Ranarivelo , Fanja Rakotomanana , 1 1 1 Rindra Randremanana , Jocelyn Ratovonjato , MarieAnge Rason , Jean 1,5 1,6 1,7 1,8 Bernard Duchemin , Adama Tall , Vincent Robert , Ronan Jambou , 1,9 1 Frédéric Ariey and Olivier Domarle

1 2 3 Address: Institut Pasteur de Madagascar, BP 1274 Antananarivo (101), Madagascar, UNICEF, Antananarivo, Madagascar, RTI/SanteNet2, Fort 4 Duschesne, Antananarivo (101), Madagascar, Service de Lutte contre le Paludisme, Ministère de la Santé et du Planning Familial, Antananarivo 5 6 7 (101), Madagascar, CERMES, Niamey, Niger, Institut Pasteur de Dakar, Sénégal, Institut de Recherche pour le Développement UR016 et 8 Muséum National d'Histoire Naturelle USM504, Centre IRD de Montpellier, B.P. 64501, 34394 Montpellier cedex 5, France, Institut Pasteur, 9 Département de Parasitologie Mycologie Paris, France and Institut Pasteur du Cambodge, Phnom Penh, Cambodge Email: Léon P Rabarijaona  [e-mail]; Milijaona Randrianarivelojosia*  [e-mail]; Lucie A Raharimalala  [e-mail]; Arsène Ratsimbasoa  [e-mail]; Arthur Randriamanantena  [e-mail]; Laurence Randrianasolo  [e-mail]; Lanto A Ranarivelo  [e-mail]; Fanja Rakotomanana  [e-mail]; Rindra Randremanana  [e-mail]; Jocelyn Ratovonjato  [e-mail]; Marie Ange Rason  [e-mail]; JeanBernard Duchemin  [e-mail]; Adama Tall  [e-mail]; Vincent Robert  [e-mail]; Ronan Jambou  [e-mail]; Frédéric Ariey  [e-mail]; Olivier Domarle  [e-mail] * Corresponding author †Equal contributors

Published: 6 August 2009 Received: 21 January 2009 Accepted: 6 August 2009 Malaria Journal2009,8:190 doi:10.1186/147528758190 This article is available from: http://www.malariajournal.com/content/8/1/190 © 2009 Rabarijaona et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Madagascar has been known for having biogeoecological diversity which is reflected by a complex malaria epidemiology ranging from hyperendemic to malariafree areas. Malariarelated attacks and infection are frequently recorded both in children and adults living in areas of low malaria transmission. To integrate this variability in the national malaria control policy, extensive epidemiological studies are required to update previous records and adjust strategies. Methods:A longitudinal malaria survey was conducted from July 1996 to June 2005 among an average cohort of 214 villagers in Saharevo, located at 900 m above the sea. Saharevo is a typical eastern foothill site at the junction between a costal wet tropical area (equatorial malaria pattern) and a drier highaltitude area (low malaria transmission). Results:Passive and active malaria detection revealed that malaria transmission in Saharevo follows an abrupt seasonal variation. Interestingly, malaria was confirmed in 45% (1,271/2,794) of malariapresumed fevers seen at the health centre. All fourPlasmodiathat infect humans were also found:Plasmodium falciparum;Plasmodium vivax,Plasmodium malariaeandPlasmodium ovale. Half of the malariapresumed fevers could be confirmed over the season with the highest malaria transmission level, although less than a quarter in lower transmission time, highlighting the

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