climate variability and dynamics of malaria and...
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Email:[email protected]
Conceptual and methodological framework
Materials & Methods
Parasitological study
Results
Climate variability and dynamics of malaria and
schistosomiasis transmission in Korhogo (northern Côte
d’Ivoire) and Kaedi (southern Mauritania)
Study context
Malaria and Schistosomiasis are the world's two most important parasitic infections in terms of distribution, morbidity and mortality. These diseases are highly sensitive to changes in the natural environment (figure 1). Environmental condition affects both the infectious pathogens, vectors and the snails intermediate host (Chastel,2006; De la Roque & Rioux,2008).The main objective of this study is to determine parasitological, entomological and malacological factors of malaria and schistosomiasis transmission in Kaédi (KAE) and Korhogo (KGO) in climate change context in order to develop adapted resilience tools.
Study Site: Korhogo (North Côte d’Ivoire): Population: 210 000 Hbts, Precipitation(mm/a): [1200-1500,] Average :1350 mm T°(min-max): [24-36°C ], Average :30 °C The climate is Sudanese Presence of a dam( Vol=107 m3 )and other small water bodies Kaédi (South Mauritania): Population: 118 195 Hbts, Precipitation(mm/a) [300-500], Average :400mm T°(min-max):[12-47°C],Average: 29.5 °C The climate is sahelian Located along the Senegal river
Key message / lessons
Lead Author
Collaborating Institutions
Three main references related to the study : 1. Chastel C., 2006 : Changements climatiques et maladies infectieuses, La Lettre de l’Infectiologue - Tome XXI - n° (6),258-262 2.De La Rocque S., Rioux J.A., 2008 : Influence des changements climatiques sur l’épidémiologie des maladies transmissibles, Bull Soc Pathol Exot,( 101), 3, 213-219 3. Duvallet Gerard,2012 :Changements globaux et maladies vectorielles émergentes, Colloque CEMI SMVIPP15/03/2012/http://www.agropolis.fr/pdf/actu/2011-colloque-homme-dans-la-nature.pdf
Constant N.G. GBALEGBA
Constant N.G. GBALEGBA1,2, Kigbafori D. SILUE, Yves-Nathan T. TIAN BI 2,3, Grégoire Y. YAPI 4, Emmanuel TIA,4 Ousmane BA6,7,Hampâté BA6, Mouhamadou CHOUAIBOU2,
Brama KONE2,5, Benjamin G. KOUDOU1,2
4 Centre d’Entomologie Médicale et Vétérinaire / Université Alassane Ouattara, Bouaké, Côte d’Ivoire 5 Université Peleforo Gon Coulibaly, Korhogo, Côte d’Ivoire 6 Institut National de Recherches en Santé Publique, Nouakchott, Mauritanie 7 Université des Sciences, de Technologie et de Médecine, Nouakchott, Mauritanie
In KGO Plasmodium parasite prevalence is respectively 17 % (583/3422) and 8% (280/3446) during the DS and RS. All the 8915 RDTs conducted in KAE were negative. However KAE’s BS result is not available. Only one case (0.05% ;1/1862) of intestinal schistosomiasis has been met in KAE. The prevalence of Schistosomiasis are summarized on figure 2.
0,0
1,0
2,0
3,0
4,0
5,0
6,0
KGO KAE
KGO KAE
KGO KAE
KGO KAE
Rainy season
Dry season
Rainy season
Dry season
Urinary Schistosomiasis
Intestinal Schistosomiasis
0.5(n=1125)
2.6(n=1233)
0.3 (n=1248)
4.4(n=1325)
6(n=1009)
0.1(n=902)
3.3(n=1202)
0.0(n=960)
Pre
vale
nce
(%)
P<0.05
In both sites, Anopheles breeding sites were skeptic thank, spoilt containers, road puddle, temporaries and permanent mares.
Anopheles larvae fauna collected is 0.3% (4/1056) in KAE against 19.44% (3803/19560) in KGO (P<0.05). An. gambiae sl adult were 6% (6/100) and 21.7 % (309/1423) respectively in KAE and KGO (P<0.05).
The aggressive rate is 0.19 and 0.35 bites per man per night (b/m/n) in KGO and in KAE 0.4(b/m/n) and 0 (b/m/n) respectively during RS and DS.
Figure 2:Prevalence of the two forms of Schistosomiasis
Seven species of snails were found in both sites. Three of them are intermediate hosts of schistosomiasis(Bulinus senegalensis, B.truncatus, Biomphalaria. pfeifferi ).
The number of intermediate host in the DS was greater than that obtained in RS (p <0.05) in the two sites.
During the DS, B. pfeifferi has been found naturally infected by cercaria of S. mansoni in KGO.
P<0.05
KORHOGO KAEDI
A cross-sectional survey (parasitological, entomological and malacological) was conducted during the rainy (RS) and dry season (DS) in KAE and KGO. Thick drops of Blood Smears (BS) and malaria Rapid Diagnostic Tests (RDT) (picture a)were conducted on subjects in the households surveyed. School age(5-15) children provided urine and stool samples which were examined using standard techniques(by filtration; double Kato-Katz smears prepared for each child). Mosquito larvae were collected by dipping and adults by pyrethrum spray catch, setting windows traps(picture b) and CDC miniature light trap (Model 512). Snails were collected in water bodies by 2 trained field collectors(picture c) using standard snail scoops or occasionally, by hand collection. Sampling time was fixed at 15 minutes per collection site.
Malacological study
Entomological study
Environment
Parasites
Vectors and
snails
Intermediate
hosts
Bulinus sp Biomphalaria sp
Anopheles sp
« Vectors borne diseases (VBDs) »
Climate Change(CC)
« Human »
•KAE and KGO are endemic to urinary schistosomiasis. •The only case of intestinal schistosomiasis encountered in KAE could be an imported case. Furthermore, no snail intermediate host of intestinal schistosomiasis (B. pfeifferi) was obtained. •Urban malaria is a reality in Korhogo, however with low Plasmodium prevalence unlike other ivorian city. •Malaria vectors are present in KAE at low density. •Laboratory analysis will allow us to better assess the level of malaria transmission in the two sites.
Field and laboratory procedures P<0.05
P<0.05
Figure 1 : Conceptual and methodological framework of the study( Duvallet, 2012 modified)
CSRS associate researcher Master degree: Medical and
Veterinary Entomology PhD Student in Biodiversity and
sustainable management of ecosystems
University Nangui Abrogoua (Côte d’Ivoire)
Email: [email protected]
Centre Suisse de Recherches Scientifiques en Côte d‘Ivoire, Research Group ecosystem and population health, 01 BP 1303 Abidjan 01, Côte d’Ivoire - tel: +225 23 47 27 90 - fax: +225 23 45 12 11 - email: [email protected], www.csrs.ch
1 UFR Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire 2 Centre Suisse de Recherches Scientifiques en Côte d’Ivoire 3 UFR Biosciences, Université Félix Houphouët Boigny, Abidjan, Côte d’Ivoire
c
b
a