The study was carried out in Dielmo, a village situated in a Sudan-savannah region of central Senegal, on the marshy bank of a small permanent stream, where anopheline mosquitoes breed all year round [22] (
link). Malaria transmission is intense and perennial, with a mean 258 and 132 infected bites per person per year during 1990–2006 and 2007–2010, respectively [21] (
link). From 1990 to 2010, we did a longitudinal study involving most of the population of the village (all 247 inhabitants of the village in June 1990 at the beginning of the project, 468 of 509 inhabitants in December 2010).
The study area, the procedures of medical, parasitological, entomological and epidemiological surveillance and the main characteristics of malaria in this village have been described previously [21] (
link), [22] (
link). Briefly, during 20 years, we visited all households daily, and collected nominative information on the presence or absence in the village of each individual we had enrolled, their location when absent, and the presence of fever or other symptoms. We systematically recorded body temperature at home three times a week (every second day except Sunday) in children younger than 5 years, and in older children and adults in case of suspected fever or fever-related symptoms. In cases of fever or other symptoms, blood testing was done by finger prick at our dispensary located in the village, and we provided detailed medical examination and specific treatment. The dispensary created for our project was open 24 h a day, 7 days a week, to allow both active and passive case detection. To investigate asymptomatic malaria carriage, we performed cross-sectional surveys at least quarterly in all individuals enrolled in the project. Blood was taken by finger prick and we examined 200 oil-immersion fields. We measured the parasite: leukocyte ratio for each plasmodial species and we enumerated separately the gametocytes of
P. falciparum.
Between June 1990 and December 2010, four first-line drugs regimens were successively used for antimalarial treatment: oral quinine (Quinimax®) (October 1990–December 1994), chloroquine (January 1995–October 2003), sulfadoxine/pyrimethamine+amodiaquine (SP+AQ) (November 2003–May 2006) and artesunate+amodiaquine (AS+AQ) (June 2006–December 2010). Antimalarials were systematically given to young children in case of fever associated with a parasite: leukocyte ratio ≥2 [22] (
link). When parasitemia was lower, the requirement for antimalarial treatment was decided taking into account all the patient's clinical, biological and epidemiological data [22] (
link). Among older children (≥10 years) and adults permanently living in the village, it was rapidly observed that clinical malaria attacks lasted only a few hours even in cases where specific malaria treatment was delayed or not taken [23] (
link), and thus in most cases (except pregnant women) only symptomatic treatment was given under close clinical surveillance (three daily visit at home until recovery) in order to reduce the selection of drug resistant malaria parasites. Urine tests carried out to detect the presence of antimalarials indicated that almost all positive results (>99%) were explained by treatments given in our clinic [22] (
link). There were no chemoprohylaxis, intermittent preventive treatment nor presumptive malaria treatment in children or adults during the time period 1990–2010. At the beginning of the project, 48.6% (children: 51.1%, adults: 47.1%) of the villagers used traditional mosquito nets, which were untreated, and this proportion remained almost unchanged until July 2008 when LLINs were distributed to all villagers.
Roucher C., Rogier C., Dieye-Ba F., Sokhna C., Tall A, & Trape J.F. (2012). Changing Malaria Epidemiology and Diagnostic Criteria for Plasmodium falciparum Clinical Malaria. PLoS ONE, 7(9), e46188.