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We retrospectively assessed the impact of chloroquine (CQ) resistance in the rural region of Niakhar, Senegal, where resistance to CQ emerged in 1992, from increases in consultations and returns of patients to the health centre following antimalarial treatment. No significant differences were observed between 1992, when chemoresistance appeared, and 2004, when first-line treatment of malaria changed, except in the private centre where practices and follow-up were distinct. In this zone of Senegal, resistance to CQ does not appear to have a high impact on malaria morbidity in health centres.

Background: Recently, it has been assumed that resistance of Plasmodium to chloroquine increased malaria mortality. The study aimed to assess the impact of chemoresistance on mortality attributable to malaria in a rural area of Senegal, since the emergence of resistance in 1992, whilst chloroquine was used as first-line treatment of malaria, until the change in national anti-malarial policy in 2003., Methods: The retrospective study took place in the demographic surveillance site (DSS) of Niakhar. Data about malaria morbidity were obtained from health records of three health care facilities, where diagnosis of malaria was based on clinical signs. Source of data concerning malaria mortality were verbal autopsies performed by trained fieldworkers and examined by physicians who identified the probable cause of death., Results: From 1992 to 2004, clinical malaria morbidity represented 39% of total morbidity in health centres. Mean malaria mortality was 2.4 per thousand and 10.4 per thousand among total population and children younger than five years, respectively, and was highest in the 1992-1995 period. It tended to decline from 1992 to 2003 (Trend test, total population p = 0.03, children 0-4 years p = 0.12 - children 1-4 years p = 0.04- children 5-9 years p = 0.01)., Conclusion: Contrary to what has been observed until 1995, mortality attributable to malaria did not continue to increase dramatically in spite of the growing resistance to chloroquine and its use as first-line treatment until 2003. Malaria morbidity and mortality followed parallel trends and rather fluctuated accordingly to rainfall.

Purpose: The aim of the study was to determine the accuracy of a rapid diagnostic test in confirming presumptive malaria diagnosis in a rural zone of Senegal. Thick blood smear was used as the reference technique for comparison. METHOHDOLOGY: Testing was conducted on children between the ages of 1 and 14 years at three health care facilities located in the Niakhar are from August 2006 to June 2007. If malaria was suspected by the nurse based on clinical findings, two thick smears and one rapid diagnostic test (Core Malaria Pf) were performed. Blood slides were stained in Niakhar and read in Dakar., Results: A total of 474 patients were examined. Three-fourths (75%) of these patients were seen during the rainy season. Malaria was suspected in 335 patients (71%). Rapid tests and thick smears were obtained in 330 of these patients with positive results in 194 (59%) and 180 (55%) respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the rapid test were 96%, 87%, 90% and 95% respectively., Conclusion: Our data show that the rapid diagnostic test used in this study exhibits good sensitivity and positive predictive value. Despite its cost this test could be helpful in confirming malaria diagnosis in outlying health care facilities without the necessary resources to perform blood smears. Confirmation is necessary to avoid unwarranted prescription of malaria treatment due to inaccurate clinical diagnosis

A demographic survey site has been implemented in Niakhar rural zone in Senegal since the 1960s and many epidemiological and demographic studies have been conducted in this context. In this Sahelo-Sudanese area, malaria transmission is mesoendemic and mainly seasonal. In health care facilities, malaria real burden is poorly known as malaria diagnosis only relies on patients' clinical signs. The aim of our study was to measure the reliability of malaria diagnosis in these health centres by performing a parasitological confirmation of presumptive malaria cases and by assessing the validity of diagnosis according to child's age. A cross-sectional study was conducted in August-December 2006 (rainy season) and in February-June 2007 (dry season) in three health care facilities of the area (2 public centres and one private dispensary). Children aged 1 to 14 years old and accompanied by an adult were included. Two thick blood smears were carried out for each patient. A total of 474 children were included; among them 208 (43.9%) had a positive blood smear. Among the 335 (70.7%) presumptive malaria cases, 182 (54.3%) were confirmed by thick smear. Sensitivity specificity positive and negative predictive values were respectively 87.5%, 42.6%, 55.3% and 80.7%. Clinical signs which were predictive of confirmed malaria were vomiting and body temperature > or =38 degrees C. Clinical diagnosis performances decreased significantly during the dry season and in children under the age of two. The proportion of true malaria cases (54.3%) confirms the results of previous studies described in literature and shows a consistency for the last twenty years. Malaria is the main diagnosis attributed to patients by health care agents, regardless of the child's age or the season, whereas thick smear results are predominantly negative among children aged less than 2 and during dry season. A better knowledge of malaria morbidity in these health care facilities is an asset for setting up further epidemiological studies in this area and implementing interventions aiming at improving patients' care.

One hundred patients were included in a randomised trial to identify surgical factors inducing malaria and assess the impact of chloroquine prophylaxis in Niamey where resistance to the drug is moderate. Thick smears were positive in 19 patients without prophylaxis (37%) versus 7 under chloroquine (15%). Factors influencing malaria were surgical intervention lasting more than 1 hour and general anaesthesia. Chloroquine prophylaxis was significantly efficient under such circumstances.

There is now accumulating evidence for the involvement of genetic factors in the control of immune response against malaria. These arguments come from numerous animal models, from population studies showing associations of red blood cell genetic defects as well as HLA antigens with severe malaria, and from familial studies including a recent segregation analysis, which led to detection of a major gene effect predisposing to high infection levels. The heterogeneity and complexity of this genetic control is one of the main findings of these previous studies, and probably a major cause of the difficulty in developing an effective malaria vaccine. A segregation analysis of blood infection levels is performed here in 44 pedigrees living in the tropical rain forest of southern Cameroon and exposed to high vectorial transmission intensity. The results confirm the existence of complex genetic factors controlling blood infection levels in human malaria but are not consistent with the parent-offspring transmission of a single Mendelian gene. This study also shows the dramatic effect of age on infection levels and its interaction with a putative major gene suggesting that genetic related differences are much more important in children than in adults. Further genetic studies focused on children may help to identify the nature of the genetic factors involved in the expression of human malaria, by means of linkage analyses using both familial information and genetic markers.

In Togo, where malaria occurs all the year, 151 children, from 6 months to 3 years old, were distributed in 2 groups, one of which received an iron supplementation during three months, and the other a placebo during the same time. At the end of the trial, no significant difference was observed between the two groups. However, taking into account malaria infection at the end of the trial, children who received iron supplementation and who were free of malaria infection showed improvement of their haematological status when compared to children receiving placebo and also free of malaria infection. Authors presumed that iron supplementation was masked by malaria when they evaluated effect of iron supplementation on anaemia.

Genetic epidemiology is a new tool for the study of malaria, with interesting incidence in the comprehension of host/parasite interrelations. The existence of a co-dominant major gene, with a mendelian transmission, controlling the levels of parasitemia has been found out. This allele has a frequency of 24% which means that about 6% of the population is predisposed to high parasitemias. These studies show the interest to integrate the existence of a genetical variability in the development and the evaluation of malaria control programmes. They are offering new perspectives in therapeutics and in the elaboration of vaccinal strategies.

A one year entomological was carried out the survey in the coastal town of Cotonou to study the urban transmission of malaria. Three representative areas of Cotonou were chosen. The method adopted concerned night catches on human bait and dissection of A. gambiae s.l. The density of the vector (A. gambiae s.l.) fluctuated with the level of urbanization of the areas the annual aggressivity rates reached 1179 in the town center, 3666 in an the outskirts and 3363 in intermediate areas. Mean sporozoitic index was 1.7% and corresponding annual inoculation rate 46. In center of the town, transmission is seasonal and short, with a very high level. Sporozoitic index is 12% and the corresponding inoculation rate is 1.02. Outside of the town, transmission is seasonal and long: lasting 8 months. Transmission is imperceptible in the middle of the dry season and at the beginning of the long rain season. Malaria transmission into urban areas is generally low but in coastal like zones Cotonou, the intensity may be higher.

The prevalence of malaria and the frequency of gene S were surveyed in two different regions of Benin, savana and coastal lacustrine regions. In both regions, prevalence of malaria was not significantly different between Hb AA people and Hb AS people. Gene S prevalence was not modified by age, excepted for Hb SS which was not found in people upper than 25 years. In holoendemic area, i.e. lacustrine region, means of P. falciparum parasitaemia were significantly lower in Hb AS children than in Hb AA children. Sickle cell trait did not reduce the prevalence of malaria but seemed to decrease the level of parasitaemia.

Malaria morbidity and mortality were measured in a population of 1500 children under 3 years of age from April to December 1989. During monthly home visits, an average of 26 children in 1000 had fever, of whom 15 had parasitaemia. Children less than 6 months old had significantly fewer fever episodes, whether associated with parasitaemia or not. Overall, prevalence of fever with parasitaemia rose steadily from April to August, then decreased but reached a second peak in November. Peaks coincided with the 2 rainy seasons in April to June and September to October. Comparison with a control group demonstrated that children with parasitaemia exceeding 1000 infected red blood cells per microliter of blood had fever significantly more often than children with lower levels of parasitaemia. The average number of fever episodes per child per year was 2.4, and 33% of these were estimated to be caused by malaria. All cause mortality was 26/1000/year and the malaria mortality rate was 8/1000/year. Malaria deaths were most frequent in the second year of life.

An iron supplementation trial had been performed in a southern village of Togo during the rainy season when occurs malaria transmission. 241 infants from 6 to 36 months old were matched in two randomized groups. The first one (G1) received oral iron supplementation every day during three months. The second group (G2) received placebo. Tablet administration was double blind made. A third group (G3) had been created from two others with anaemic infants and received daily iron supplementation. Three biological and clinical surveys were done, i) before the trial (T0), ii) after supplementation (T3) and iii) six months later (T9). Several parameters were studied including malaria parasite density and titration of malaria antibodies. For each group the prevalence of Plasmodium falciparum was identical in the three surveys. Means of parasite density decreased during and after rainy season but variations were not significant. High parasitaemia frequency (i.e. greater than 10,000 parasitized red cells per mm3, considered as pyrogenic threshold) were identical in all groups and decreased after rainy season. Antibodies titers did not show any variation in the three groups. It seems that iron supplementation did not modify in 6 to 36 months infants the susceptibility to malaria nor the organism response.

Authors report on a prospective study about malaria morbidity, carried out from April 1988 to March 1989. Malaria diagnosis was based on: 1. An unexplained fever, hours before, during or after entrance. 2. A parasitic density superior to 3,000 trophozoites per mm3 of blood. 3. Efficacy of parenteral malaria therapy. Among 480 hospitalized children, 20% suffered from a malaria attack; 44% of malaria attacks occurred within 6 and 23 months of age. Thus, malaria incidence seems considerable in this urban and lagoon environment. Malaria attacks were observed all year long but with unequal seasonal rates of incidence. As regards malaria morbidity studies, we propose that rates of incidence should be calculated according to several parasitic density thresholds so as to be able to compare various works.