A Functional IL22 Polymorphism (rs2227473) Is Associated with Predisposition to Childhood Cerebral Malaria

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection. This encephalopathy is characterized by coma and is thought to result from mechanical microvessel obstruction and an excessive activation of immune cells leading to pathological inflammation and blood-brain barrier alterations. IL-22 contributes to both chronic inflammatory and infectious diseases, and may have protective or pathogenic effects, depending on the tissue and disease state. We evaluated whether polymorphisms (n = 46) of IL22 and IL22RA2 were associated with CM in children from Nigeria and Mali. Two SNPs of IL22, rs1012356 (P = 0.016, OR = 2.12) and rs2227476 (P = 0.007, OR = 2.08) were independently associated with CM in a sample of 115 Nigerian children with CM and 160 controls. The association with rs2227476 (P = 0.01) was replicated in 240 nuclear families with one affected child from Mali. SNP rs2227473, in linkage disequilibrium with rs2227476, was also associated with CM in the combined cohort for these two populations, (P = 0.004, OR = 1.55). SNP rs2227473 is located within a putative binding site for the aryl hydrocarbon receptor, a master regulator of IL-22 production. Individuals carrying the aggravating T allele of rs2227473 produced significantly more IL-22 than those without this allele. Overall, these findings suggest that IL-22 is involved in the pathogenesis of CM.

The Regulation of Inherently Autoreactive VH4-34-Expressing B Cells in Individuals Living in a Malaria-Endemic Area of West Africa

Plasmodium falciparum malaria is a deadly infectious disease in which Abs play a critical role in naturally acquired immunity. However, the specificity and nature of Abs elicited in response to malaria are only partially understood. Autoreactivity and polyreactivity are common features of Ab responses in several infections and were suggested to contribute to effective pathogen-specific Ab responses. In this article, we report on the regulation of B cells expressing the inherently autoreactive VH4-34 H chain (identified by the 9G4 mAb) and 9G4⁺ plasma IgG in adults and children living in a P. falciparum malaria-endemic area in West Africa. The frequency of 9G4⁺ peripheral blood CD19⁺ B cells was similar in United States adults and African adults and children; however, more 9G4⁺ B cells appeared in classical and atypical memory B cell compartments in African children and adults compared with United States adults. The levels of 9G4⁺ IgG increased following acute febrile malaria but did not increase with age as humoral immunity is acquired or correlate with protection from acute disease. This was the case, even though a portion of 9G4⁺ B cells acquired phenotypes of atypical and classical memory B cells and 9G4⁺ IgG contained equivalent numbers of somatic hypermutations compared with all other VHs, a characteristic of secondary Ab repertoire diversification in response to Ag stimulation. Determining the origin and function of 9G4⁺ B cells and 9G4⁺ IgG in malaria may contribute to a better understanding of the varied roles of autoreactivity in infectious diseases.

Safety, reactogenicity and immunogenicity of 2-dose catch-up vaccination with 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in Malian children in the second year of life: Results from an open study

Pneumonia is still the leading cause of death among African children with pneumococcal serotypes 1 and 5 being dominant in the below 5 y of age group. The present study assessed the safety, reactogenicity and immunogenicity of a 2-dose catch-up vaccination with the 10-valent pneumococcal non-typeable Haemophilus influenzae Protein D conjugate vaccine (PHiD-CV) in Malian children. This phase III, open-label study (NCT00985465) was conducted in Ouelessebougou, Mali, between November 2009 and July 2010. The study population consisted of PHiD-CV unprimed Malian children previously enrolled in the control group of study NCT00678301 receiving a 2-dose catch-up vaccination with PHiD-CV in the second year of life. Adverse events were recorded following each PHiD-CV dose. Antibody responses and opsonophagocytic activity (OPA) were measured pre-vaccination and after the second PHiD-CV catch-up dose. Swelling and fever (axillary temperature ≥ 37.5°C) were the most frequently reported solicited symptoms following either PHiD-CV dose. Few grade 3 solicited symptoms were reported. Large swelling reactions and serious adverse events were not reported. Post-catch-up vaccination, for each vaccine pneumococcal serotype, at least 94.7% of subjects had antibody concentrations ≥ 0.2 μg/ml, except for serotypes 6B (82.5%) and 23F (87.7%). At least 94.0% of subjects had OPA titres ≥ 8, except for serotype 19F (89.4%). The geometric mean concentration for antibodies against protein D was 839.3 (95% CI: 643.5-1094.6) EL.U/ml. Two-dose PHiD-CV catch-up regimen in the second year of life was well-tolerated and immunogenic for all vaccine pneumococcal serotypes and NTHi protein D when administered to Malian children

Do advanced glycation end-products play a role in malaria susceptibility?

There are growing data supporting the differences in susceptibility to malaria described between sympatric populations with different lifestyles. Evidence has also been growing for some time that nutritional status and the host's metabolism are part of the complex mechanisms underlying these differences. The role of dietary advanced glycation end-products (AGEs) in the modulation of immune responses (innate and adaptive responses) and chronic oxidative stress has been established. But less is known about AGE implication in naturally acquired immunity and susceptibility to malaria. Since inflammatory immune responses and oxidative events have been demonstrated as the hallmark of malaria infection, it seems crucial to investigate the role of AGE in susceptibility or resistance to malaria. This review provides new insight into the relationship between nutrition, metabolic disorders, and infections, and how this may influence the mechanisms of susceptibility or resistance to malaria in endemic areas.

Identification of blood meal sources in the main African malaria mosquito vector by MALDI-TOF MS

BACKGROUND

The identification of blood meal sources in malaria vectors is critical to better understanding host/vector interactions and malaria epidemiology and control. Currently, the identification of mosquito blood meal origins is based on time-consuming and costly techniques such as precipitin tests, ELISA and molecular tools. Although these tools have been validated to identify the blood meal and trophic preferences of female Anopheles mosquitoes, they present several limitations. Recently, matrix-assisted, laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was successfully used as a quick and accurate tool for arthropod identification, including mosquitoes. The aim of the present work was to test whether MALDI-TOF MS could also be applied to identification of blood meal sources from engorged mosquitoes.

METHODS

Abdomen proteins extracted from Anopheles gambiae (stricto sensu, S molecular form) that were either unengorged or artificially engorged on seven distinct types of vertebrate blood (human, horse, sheep, rabbit, mouse, rat, dog) were submitted for MALDI-TOF MS.

RESULTS

The comparison of mass spectrometry (MS) spectra from mosquito abdomens collected 1 h post-feeding, were able to discriminate blood meal origins. Moreover, using Aedes albopictus specimens, abdominal protein MS spectra from engorged mosquitoes were found specific to host blood source and independent of the mosquito species. A sequential analysis revealed stability of mosquito abdominal protein spectra up to 24 h post-feeding.

CONCLUSIONS

These results indicate that MALDI-TOF MS could determine feeding patterns of freshly engorged mosquitoes up to 24 h post-blood meal. The MALDI-TOF MS technique appears to be an efficient tool for large epidemiological surveillance of vector-borne diseases and outbreak source identification.

Non-falciparum malaria infections in pregnant women in West Africa

BACKGROUND

Non-Plasmodium falciparum malaria infections are found in many parts of sub-Saharan Africa but little is known about their importance in pregnancy.

METHODS

Blood samples were collected at first antenatal clinic attendance from 2526 women enrolled in a trial of intermittent screening and treatment of malaria in pregnancy (ISTp) versus intermittent preventive treatment (IPTp) conducted in Burkina Faso, The Gambia, Ghana and Mali. DNA was extracted from blood spots and tested for P. falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale using a nested PCR test. Risk factors for a non-falciparum malaria infection were investigated and the influence of these infections on the outcome of pregnancy was determined.

RESULTS

P. falciparum infection was detected frequently (overall prevalence by PCR: 38.8 %, [95 % CI 37.0, 40.8]), with a prevalence ranging from 10.8 % in The Gambia to 56.1 % in Ghana. Non-falciparum malaria infections were found only rarely (overall prevalence 1.39 % [95 % CI 1.00, 1.92]), ranging from 0.17 % in the Gambia to 3.81 % in Mali. Ten non-falciparum mono-infections and 25 mixed falciparum and non-falciparum infections were found. P. malariae was the most frequent non-falciparum infection identified; P. vivax was detected only in Mali. Only four of the non-falciparum mono-infections were detected by microscopy or rapid diagnostic test. Recruitment during the late rainy season and low socio-economic status were associated with an increased risk of non-falciparum malaria as well as falciparum malaria. The outcome of pregnancy did not differ between women with a non-falciparum malaria infection and those who were not infected with malaria at first ANC attendance.

CONCLUSIONS

Non-falciparum infections were infrequent in the populations studied, rarely detected when present as a mono-infection and unlikely to have had an important impact on the outcome of pregnancy in the communities studied due to the small number of women infected with non-falciparum parasites.

Distribution of FcγR gene polymorphisms among two sympatric populations in Mali: differing allele frequencies, associations with malariometric indices and implications for genetic susceptibility to malaria

Background

Genetic polymorphisms in the complex gene cluster encoding human Fc-gamma receptors (FcγRs) may influence malaria susceptibility and pathogenesis. Studying genetic susceptibility to malaria is ideal among sympatric populations because the distribution of polymorphic genes among such populations can help in the identification malaria candidate genes. This study determined the distribution of three FcyRs single nucleotide polymorphisms (SNPs) (FcγRIIB-rs1050519, FcγRIIC-rs3933769 and FcγRIIIA-rs396991) among sympatric Fulani and Dogon children with uncomplicated malaria. The association of these SNPs with clinical, malariometric and immunological indices was also tested.

Methods

This study involved 242 Fulani and Dogon volunteers from Mali age under 15 years. All SNPs were genotyped with predesigned TaqMan^® SNP Genotyping Assays. Genotypic and allelic distribution of SNPs was compared across ethnic groups using the Fisher exact test. Variations in clinical, malariometric and immunologic indices between groups were tested with Kruskal–Wallis H, Mann–Whitney U test and Fisher exact test where appropriate.

Results

The study confirmed known malariometric and immunologic differences between sympatric Fulani and non-Fulani tribes. Parasite density was lower in the Fulani than the Dogon (p < 0.0001). The mutant allele of FcγRIIC (rs3933769) was found more frequently in the Fulani than the Dogon (p < 0.0001) while that of FcγRIIIA (rs396991) occurred less frequently in the Fulani than Dogon (p = 0.0043). The difference in the mutant allele frequency of FcγRIIB (rs1050519) between the two ethnic groups was however not statistically significant (p = 0.064). The mutant allele of rs396991 was associated with high malaria-specific IgG1 and IgG3 in the entire study population and Dogon tribe, p = 0.023 and 0.015, respectively. Parasite burden was lower in carriers of the FcγRIIC (rs3933769) mutant allele than non-carriers in the entire study population (p < 0.0001). Carriers of this allele harboured less than half the parasites found in non-carriers.

Conclusion

Differences in the allelic frequencies of rs3933769 and rs396991 among Fulani and Dogon indirectly suggest that these SNPs may influence malaria susceptibility and pathogenesis in the study population. The high frequency of the FcγRIIC (rs3933769) mutant allele in the Fulani and its subsequent association with low parasite burden in the entire study population is noteworthy.

Impact of Sulfadoxine-Pyrimethamine Resistance on Effectiveness of Intermittent Preventive Therapy for Malaria in Pregnancy at Clearing Infections and Preventing Low Birth Weight

BACKGROUND

Owing to increasing sulfadoxine-pyrimethamine (SP) resistance in sub-Saharan Africa, monitoring the effectiveness of intermittent preventive therapy in pregnancy (IPTp) with SP is crucial.

METHODS

Between 2009 and 2013, both the efficacy of IPTp-SP at clearing existing peripheral malaria infections and the effectiveness of IPTp-SP at reducing low birth weight (LBW) were assessed among human immunodeficiency virus-uninfected participants in 8 sites in 6 countries. Sites were classified as high, medium, or low resistance after measuring parasite mutations conferring SP resistance. An individual-level prospective pooled analysis was conducted.

RESULTS

Among 1222 parasitemic pregnant women, overall polymerase chain reaction-uncorrected and -corrected failure rates by day 42 were 21.3% and 10.0%, respectively (39.7% and 21.1% in high-resistance areas; 4.9% and 1.1% in low-resistance areas). Median time to recurrence decreased with increasing prevalence of Pfdhps-K540E. Among 6099 women at delivery, IPTp-SP was associated with a 22% reduction in the risk of LBW (prevalence ratio [PR], 0.78; 95% confidence interval [CI], .69-.88; P < .001). This association was not modified by insecticide-treated net use or gravidity, and remained significant in areas with high SP resistance (PR, 0.81; 95% CI, .67-.97; P = .02).

CONCLUSIONS

The efficacy of SP to clear peripheral parasites and prevent new infections during pregnancy is compromised in areas with >90% prevalence of Pfdhps-K540E. Nevertheless, in these high-resistance areas, IPTp-SP use remains associated with increases in birth weight and maternal hemoglobin. The effectiveness of IPTp in eastern and southern Africa is threatened by further increases in SP resistance and reinforces the need to evaluate alternative drugs and strategies for the control of malaria in pregnancy.

A Non-Inferiority, Individually Randomized Trial of Intermittent Screening and Treatment versus Intermittent Preventive Treatment in the Control of Malaria in Pregnancy

BACKGROUND

The efficacy of intermittent preventive treatment for malaria with sulfadoxine-pyrimethamine (IPTp-SP) in pregnancy is threatened in parts of Africa by the emergence and spread of resistance to SP. Intermittent screening with a rapid diagnostic test (RDT) and treatment of positive women (ISTp) is an alternative approach.

METHODS AND FINDINGS

An open, individually randomized, non-inferiority trial of IPTp-SP versus ISTp was conducted in 5,354 primi- or secundigravidae in four West African countries with a low prevalence of resistance to SP (The Gambia, Mali, Burkina Faso and Ghana). Women in the IPTp-SP group received SP on two or three occasions whilst women in the ISTp group were screened two or three times with a RDT and treated if positive for malaria with artemether-lumefantrine (AL). ISTp-AL was non-inferior to IPTp-SP in preventing low birth weight (LBW), anemia and placental malaria, the primary trial endpoints. The prevalence of LBW was 15.1% and 15.6% in the IPTp-SP and ISTp-AL groups respectively (OR = 1.03 [95% CI: 0.88, 1.22]). The mean hemoglobin concentration at the last clinic attendance before delivery was 10.97g/dL and 10.94g/dL in the IPTp-SP and ISTp-AL groups respectively (mean difference: -0.03 g/dL [95% CI: -0.13, +0.06]). Active malaria infection of the placenta was found in 24.5% and in 24.2% of women in the IPTp-SP and ISTp-AL groups respectively (OR = 0.95 [95% CI 0.81, 1.12]). More women in the ISTp-AL than in the IPTp-SP group presented with malaria parasitemia between routine antenatal clinics (310 vs 182 episodes, rate difference: 49.4 per 1,000 pregnancies [95% CI 30.5, 68.3], but the number of hospital admissions for malaria was similar in the two groups.

CONCLUSIONS

Despite low levels of resistance to SP in the study areas, ISTp-AL performed as well as IPTp-SP. In the absence of an effective alternative medication to SP for IPTp, ISTp-AL is a potential alternative to IPTp in areas where SP resistance is high. It may also have a role in areas where malaria transmission is low and for the prevention of malaria in HIV positive women receiving cotrimoxazole prophylaxis in whom SP is contraindicated.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01084213 Pan African Clinical trials Registry PACT201202000272122.

Drying anti-malarial drugs in vitro tests to outsource SYBR green assays

BACKGROUND

Measurement of anti-malarial drug efficacy and resistance relies mainly on in vivo clinical trials, in vitro/ex vivo assays and molecular markers detection. The existing in vitro/ex vivo assays, in particular those that are using non-radioactive devices, need to be standardized and adapted to field conditions. SYBR Green assay offers a rapid and cheap alternative to other in vitro assays, but it requires tools not commonly available in field laboratories. Here is described a modified SYBR green I protocol to perform the parasite growth test with blood samples in endemic areas, followed later by the SYBR green fluorescence assay performed at a specialized laboratory level.

METHODS

In vitro susceptibility of Plasmodium falciparum clones HB3, 3D7, W2 and 7G8 to chloroquine (CQ), dihydroartemisinin (DHA), pyronaridine (PYD) and piperaquine (PPQ) was tested. Fresh isolates of P. falciparum from imported malaria cases were collected for ex vivo assays. The parasite suspension was added in 96-well plates predosed with anti-malarial drugs and incubated for 72 hours at 37°C, 5% CO2. SYBR green I protocol was modified to dry the plates after freeze-thawed process to mimic storage and shipping conditions. The plates were rehydrated with 200 μl of complete RPMI medium for fluorescence assay.

RESULTS

There were no significant differences in IC₅₀ values of CQ, DHA, PYD and PPQ, determined by the modified protocol, compared to standard protocol. Longer storage did not affect the IC₅₀ values.

CONCLUSION

The SYBR green I modified protocol produced reliable results and could be a suitable method for in vitro/ex vivo assays in field.

Urban schistosomiasis and associated determinant factors among school children in Bamako, Mali, West Africa

BACKGROUND

Schistosomiasis is classically described as a rural disease that occurs in areas with poor sanitary conditions. However, over recent decades, there has been an expansion of schistosomiasis foci towards urban areas faced with a rapid and disordered urbanization. In Bamako, Mali, the impact of environmental change on vector-borne diseases such as schistosomiasis is not well known. This study sought to identify the presence of schistosomiasis transmission hotspots in Bamako. Using this perspective, we aimed to describe the risk factors of the endemization and maintenance of schistosomiasis.

MATERIALS AND METHODS

A cross-sectional study was carried out in the six municipalities (communes) in Bamako. Environmental information was obtained from earth observation satellites in order to maximize ecological contrasts. Twenty-nine blocks of 200 m x 200 m were identified. We selected a school inside or nearest to each block for urine and stool samples examination. The study cohort was school children aged between eight and 15 years. The Kato-Katz technique and filtration were used for Schistosoma mansoni and S. haematobium ova research in stools and urine, respectively. The schools and snail breeding sites were georeferenced. Four malacological surveys were conducted between October 2011 and February 2012. Bivariate analysis was used to identify independent predictors of being infected with schistosomiasis.

RESULTS

The prevalence rate of S. haematobium was 14.7% (n = 1,761) and that of S. mansoni 1.5% (n = 1,491). Overall, the urinary form was endemic in 76.6% of schools. The infection significantly varied between the municipalities (p < 0.001). It was also more prevalent on the left side of the Niger River than the right side (17.4% vs. 9.5% respectively; p < 0.001). The vicinity to snail breeding sites (OR = 3.677; 95% IC [2.765-4.889]; p < 10 (-3) ) and parents' occupations (OR = 7.647; 95% IC [2.406-24.305]; p < 0.001) were the most important risk factors associated with S. haematobium infection exposure. Biomphalaria pfeifferi, Bulinus truncatus, and B. globosus were the intermediate hosts captured. The schistosome natural infection rates (SNIRs), which were low or nil in October and November, rose to 2.8% in January and 8.3% in February for B. pfeifferi and B. truncatus, respectively.

CONCLUSION

Our findings show that there is a high transmission risk for schistosomiasis in Bamako. Appropriate integrated control measures need to be introduced to control the transmission of this disease in the study area.

Surveillance for antimicrobial drug resistance in under-resourced countries

TOC summary: New programs can be improved by drawing on lessons from previous successful efforts.

Antimicrobial drug resistance is usually not monitored in under-resourced countries because they lack surveillance networks, laboratory capacity, and appropriate diagnostics. This accelerating problem accounts for substantial number of excess deaths, especially among infants. Infections particularly affected by antimicrobial drug resistance include tuberculosis, malaria, severe acute respiratory infections, and sepsis caused by gram-negative bacteria. Nonetheless, mapping antimicrobial drug resistance is feasible in under-resourced countries, and lessons can be learned from previous successful efforts. Specimen shipping conditions, data standardization, absence of contamination, and adequate diagnostics must be ensured. As a first step toward solving this problem, we propose that a road map be created at the international level to strengthen antimicrobial resistance surveillance in under-resourced countries. This effort should include a research agenda; a map of existing networks and recommendations to unite them; and a communication plan for national, regional, and international organizations and funding agencies.

[Study of the impact of breeding sites on the infectivity of P. falciparum gametocytes to An. gambiae s.l in malaria-endemic area of Nanguilabougou.-Mali]

Numerous studies have shown the influence of some bacteria colonizing the breeding sites on the development of the parasite in Anopheles malaria vectors. The aim of this study was to evaluate the impact of the breeding sites of Plasmodium falciparum on the gametocytes infectivity of Anopheles gambiae sl using the membrane feeding method. We carried out an experimental infestation study from September 2010 to January 2011 in a village located in the southern savanna of Mali. Cross sectional surveys were conducted to collect larvae and to select gametocyte carriers. Female offspring of L3 and L4 stage larvae were used for the experimental infestation. The gametocyte carriers were children aged within 4 to 12 years. Bacteria identified in breeding water of larvae and adult mosquitoes were: Escherichia coli, Salmonella spp, Klebsiella oxytoca, Pseudomonas spp, Staphylococcus spp, Shigella sp. The oocyst load of infected mosquitoes did not significantly vary according to the samples (F = 1.517, P = 0.230). Low infection rates (5.4% and 2.8%) were observed in the larval bedding and in mosquitoes containing K. oxytoca and Shigella. The blood feeding rates (62.4%; 60.9%; 67.7%) and mortality (66.4%; 64.9%; 61.9%) of An. gambiae did not significantly vary depending on the breeding sites [(P = 0.15); (P = 0.22)].

Coxiella burnetii-positive PCR in febrile patients in rural and urban Africa

OBJECTIVES

Q fever has been reported throughout the African continent. The objective of this study was to detect the presence of Coxiella burnetii in febrile patients from Africa.

METHODS

Blood samples from febrile and non-febrile patients from six African countries and from France were investigated retrospectively for Q fever infection by molecular assays targeting the IS1111 and IS30A spacers.

RESULTS

We tested 1888 febrile patients from Senegal, Mali, Tunisia, Algeria, Gabon, and Morocco and found one male adult patient (0.3%) infected with C. burnetii in Algeria and six positive patients (0.5%) in Senegal. For one patient from Senegal we determined that the infection was caused by C. burnetii genotype 35. In Senegal, more patients were infected with C. burnetii in Keur Momar Sarr (p=0.002) than in the other locations. Blood samples taken from 500 (51% males) non-febrile people from Senegal and France were all negative.

CONCLUSIONS

The installation of point-of-care laboratories in rural Africa can be a very effective tool for studying the epidemiology of many infectious diseases.

Co-infection of long-term carriers of Plasmodium falciparum with Schistosoma haematobium enhances protection from febrile malaria: a prospective cohort study in Mali

Background

Malaria and schistosomiasis often overlap in tropical and subtropical countries and impose tremendous disease burdens; however, the extent to which schistosomiasis modifies the risk of febrile malaria remains unclear.

Methods

We evaluated the effect of baseline S. haematobium mono-infection, baseline P. falciparum mono-infection, and co-infection with both parasites on the risk of febrile malaria in a prospective cohort study of 616 children and adults living in Kalifabougou, Mali. Individuals with S. haematobium were treated with praziquantel within 6 weeks of enrollment. Malaria episodes were detected by weekly physical examination and self-referral for 7 months. The primary outcome was time to first or only malaria episode defined as fever (≥37.5°C) and parasitemia (≥2500 asexual parasites/µl). Secondary definitions of malaria using different parasite densities were also explored.

Results

After adjusting for age, anemia status, sickle cell trait, distance from home to river, residence within a cluster of high S. haematobium transmission, and housing type, baseline P. falciparum mono-infection (n = 254) and co-infection (n = 39) were significantly associated with protection from febrile malaria by Cox regression (hazard ratios 0.71 and 0.44; P = 0.01 and 0.02; reference group: uninfected at baseline). Baseline S. haematobium mono-infection (n = 23) did not associate with malaria protection in the adjusted analysis, but this may be due to lack of statistical power. Anemia significantly interacted with co-infection (P = 0.009), and the malaria-protective effect of co-infection was strongest in non-anemic individuals. Co-infection was an independent negative predictor of lower parasite density at the first febrile malaria episode.

Conclusions

Co-infection with S. haematobium and P. falciparum is significantly associated with reduced risk of febrile malaria in long-term asymptomatic carriers of P. falciparum. Future studies are needed to determine whether co-infection induces immunomodulatory mechanisms that protect against febrile malaria or whether genetic, behavioral, or environmental factors not accounted for here explain these findings.

The parasitic diseases malaria and schistosomiasis are tremendous public health burdens, each affecting over 200 million people worldwide with substantial geographic overlap in sub-Saharan Africa. Understanding how schistosomiasis influences the human immune response to Plasmodium, the agent of malaria, can be important for developing effective malaria vaccines. Past studies have tried to determine if infection with Schistosoma haematobium, which causes urinary schistosomiasis, affects the number of febrile attacks from malaria caused by Plasmodium falciparum in communities where the diseases overlap, but the findings have been inconsistent. Here, we examined 616 healthy people from a village in Mali for symptomless infections with S. haematobium and treated those with infections. We then followed them over a single malaria-transmission season of 7 months during which we diagnosed and treated all febrile malaria attacks. After the season, we examined archived blood collected at enrollment to look for occult P. falciparum infection. The study revealed that people who were infected with both parasites at the beginning of the season were better protected from the malaria attacks than those who were uninfected or infected with either parasite alone. Further studies are needed to confirm these findings and to determine the biological basis for this phenomenon.

[Frequency of glucose-6-phosphate dehydrogenase deficiency (A-376/202) in three Malian ethnic groups]

Erythrocyte G6PD deficiency is the most common worldwide enzymopathy. The aim of this study was to determine erythrocyte G6PD deficiency in 3 ethnic groups of Mali and to investigate whether erythrocyte G6PD deficiency was associated to the observed protection against malaria seen in Fulani ethnic group. The study was conducted in two different areas of Mali: in the Sahel region of Mopti where Fulani and Dogon live as sympatric ethnic groups and in the Sudanese savannah area where lives mostly the Malinke ethnic group. The study was conducted in 2007 in Koro and in 2008 in Naguilabougou. It included a total 90 Dogon, 42 Fulani and 80 Malinke ethnic groups. Malaria was diagnosed using microscopic examination after Giemsa-staining of thick and thin blood smear. G6PD deficiency (A-(376/202)) samples were identified using RFLP (Restriction Fragment Length Polymorphism) assay and analysis of PCR-amplified DNA amplicon. G6PD deficiency (A-(376/202)) rate was 11.1%, 2.4%, and 13.3% in Dogon, Fulani, and Malinke ethnic group respectively. Heterozygous state for G6PD (A-(376/202)) was found in 7.8% in Dogon; 2.4% in Fulani and 9.3% in Malinke ethnic groups while hemizygous state was found at the frequency of 2.2% in Dogon and 4% in Malinke. No homozygous state was found in our study population.We conclude that G6PD deficiency is not differing significantly between the three ethnic groups, Fulani, Dogon and Malinke.

Preliminary study of the fungal ecology at the haematology and medical-oncology ward in Bamako, Mali

Data on fungal epidemiology in sub-Saharan African countries are scarce. This exploratory study aimed to characterize the fungal flora at the Onco-Haematology ward of the National Teaching Hospital of Point G in Bamako, Mali. A cross-sectional survey was conducted in the dry and in the rainy seasons. Nasal swab and sputum samples were collected from the hospitalized patients while airborne fungal spores were collected using electrostatic dust-fall collectors. Fungi were identified by their morphological characteristics and MALDI-TOF mass spectrometry. Candida albicans was the most frequent yeast species colonizing patients; Aspergillus species were isolated in 86 % of the patients and were the main airborne environmental contaminants. Overall, airborne fungal contamination rates increased from 33.8 % in the dry to 66.2 % in the rainy season (p < 0.001). The most frequent Aspergillus species were Aspergillus niger (36.6 %) and Aspergillus flavus (32.92 %). In contrast, Aspergillus fumigatus (5.43 %) was relatively rare. This high level of fungal exposure raises concern regarding the management of at-risk patients in this Onco-Haematology ward and stresses the need for strengthening the mycological diagnostic capacities to accompany the implementation of adapted fungal infection prevention and management policies.

Guinea worm (Dracunculiasis) eradication: update on progress and endgame challenges

The International Commission for the Certification of Dracunculiasis Eradication (ICCDE) met in December to review progress towards eradication. The status of the programme was presented by WHO and The Carter Center, Atlanta. The Commission received reports from international certification teams that Cote d'Ivoire, Niger and Nigeria were free of transmission and should be certified, while four countries, namely Chad, Ethiopia, Mali and South Sudan, remained endemic. The Commission certified that Somalia and South Africa were free of transmission. During 2013, there was a decline of about 78% in the numbers of cases reported in South Sudan. A report of the perplexing dracunculiasis epidemiology in Chad was also discussed, where dogs have been found to be infected with Dracunculus medinensis.

HLA-G UTR haplotype conservation in the Malian population: association with soluble HLA-G

The HLA-G molecule plays an important role in immunomodulation. In a previous study carried out on a southern French population our team showed that HLA-G haplotypes, defined by SNPs in the coding region and specific SNPs located in 5'URR and 3'UTR regulatory regions, are associated with differential soluble HLA-G expression (sHLA-G). Furthermore, the structure of these HLA-G haplotypes appears to be conserved in geographically distant populations. The aim of our study is to confirm these expectations in a sub-Saharan African population and to explore additional factors, such as HLA-A alleles, that might influence sHLA-G expression. DNA and plasma samples were collected from 229 Malians; HLA-G and HLA-A genotyping were respectively performed by the Snap Shot® method and by Luminex™ technology. sHLA-G dosage was performed using an ELISA kit. HLA-G and HLA-A allelic and haplotypic frequencies were estimated using an EM algorithm from the Gene[Rate] program. Associations between genetic and non genetic parameters with sHLA-G were performed using a non-parametric test with GRAPH PAD Prism 5. Our results reveal a good conservation of the HLA-G UTR haplotype structure in populations with different origins and demographic histories. These UTR haplotypes appear to be involved in different sHLA-G expression patterns. Specifically, the UTR-2 haplotype was associated with low sHLA-G levels, displaying a dominant negative effect. Furthermore, an allelic effect of both HLA-G and HLA-A, as well as non genetic parameters, such as age and gender possibly linked to osteogenesis and sexual hormones, also seem to be involved in the modulation of sHLA-G. These data suggest that further investigation in larger cohorts and in populations from various ethnical backgrounds is necessary not only to detect new functional polymorphism in HLA-G regulatory regions, but also to reveal the extent of biological phenomena that influence sHLA-G secretion and this might therefore have an impact on transplantation practice.

Haptoglobin phenotype prevalence and cytokine profiles during Plasmodium falciparum infection in Dogon and Fulani ethnic groups living in Mali

Background

The Fulani are known to have a lower parasitaemia and less clinical episodes of malaria as compared to the Dogon sympatric ethnic group, living in Mali. Higher circulating malaria-specific antibody titers and increased pro-inflammatory cytokine levels have been shown in Fulani individuals. Several studies have tried to link haptoglobin (Hp) phenotypes with susceptibility to malaria, but without consensus. This study investigated the role of Hp phenotypes and cytokine levels in Dogon and Fulani during asymptomatic Plasmodium falciparum infection.

Methods

Two different cohorts were combined in this study: a 2008 cohort with 77 children aged between two and ten years and a 2001 cohort, with 82 children and adults, aged between 11 and 68 years. Hp phenotypes in plasma were measured by Western Blot. Circulating levels of sCD163, IL-6, IL-10, IFN-γ and TNF were measured by ELISA. Multiple regression analysis was performed to associate Hp phenotypes with cytokine profiles. In addition, in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with Hp:Hb complexes was performed and cytokine release in corresponding supernatants were measured using cytometric bead array.

Results

The results revealed a higher Hp2-2 phenotype prevalence in the Fulani. The Hp2-2 phenotype was associated with a higher susceptibility to P. falciparum infection in Dogon, but not in Fulani. In concordance with previous studies, Fulani showed increased inflammatory mediators (IL-6, IFN-γ) and additionally also increased sCD163 levels compared to Dogon, irrespective of infection. Furthermore, infected individuals showed elevated sCD163 levels compared to uninfected individuals, in both Fulani and Dogon. Multiple regression analysis revealed that the Hp1-1 phenotype was associated with higher levels of TNF and IFN-γ, as compared to the Hp2-2 phenotype. In vitro stimulation of PBMCs with Hb:Hp1-1 complexes resulted in a pro-inflammatory cytokine profile, whilst stimulation with Hb:Hp2-2 complexes showed a more balanced profile.

Conclusions

Ethnicity might be an important confounder on the Hp phenotype-dependent susceptibility to malaria and future studies could consider taking this into account when designing new immunological studies. Although, the relatively small sample size used in this study warrens for precautions in the interpretation of the data and these findings should ideally be validated in a bigger cohort.

Common epidemiology of Rickettsia felis infection and malaria, Africa

This study aimed to compare the epidemiology of Rickettsia felis infection and malaria in France, North Africa, and sub-Saharan Africa and to identify a common vector. Blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for R. felis and Plasmodium spp. We observed a significant linear trend (p<0.0001) of increasing risk for R. felis infection. The risks were lowest in France, Tunisia, and Algeria (1%), and highest in rural Senegal (15%). Co-infections with R. felis and Plasmodium spp. and occurrences of R. felis relapses or reinfections were identified. This study demonstrates a correlation between malaria and R. felis infection regarding geographic distribution, seasonality, asymptomatic infections, and a potential vector. R. felis infection should be suspected in these geographical areas where malaria is endemic. Doxycycline chemoprophylaxis against malaria in travelers to sub-Saharan Africa also protects against rickettsioses; thus, empirical treatment strategies for febrile illness for travelers and residents in sub-Saharan Africa may require reevaluation.

Factors associated with coverage of praziquantel for schistosomiasis control in the community-direct intervention (CDI) approach in Mali (West Africa)

BACKGROUND

Despite the progress made in the control of Neglected Tropical Diseases (NTD), schistosome and soil-transmitted helminth infections are far from being effectively managed in many parts of the world. Chemotherapy, the key element of all control strategies, is faced with some difficulties in terms of access to treatment. Our study aims to describe the factors involved in the success or failure of the community-directed intervention (CDI) approach through control programmes, which aims to achieve consistent high coverage at affordable and sustainable costs in endemic areas.

METHODS

The CDI approach was carried out from December 2007 to October 2008 in ten villages of the district of Diéma, Mali. At inclusion, each child part of the study's sample was interviewed and submitted for a physical examination. The study focused on: data collection, treatment of the eligible population, evaluation of the treatment coverage, performance of community drug distributors (CDDs), and the involvement and perception of populations.

RESULTS

A total of 8,022 eligible people were studied with a mean coverage rate of 76.7%. Using multiple regression, it was determined that receiving praziquantel as treatment was associated with five factors: belonging to the Fulani or Moorish ethnic minority versus the Bambara/Soninke, use of the central versus the house-to-house drug distribution mode, the ratio of the population to the number of CDDs, the lack of supervision and belonging to the age group of 15 years or above (p<0.05). As well as that, it was found that the presence of parallel community-based programmes (HIV, tuberculosis) that provide financial incentives for community members discouraged many CDDs (who in most cases are volunteers) to participate in the CDI approach due to a lack of incentives.

CONCLUSIONS

The findings indicate that the success of the CDI approach depends on, amongst other things, the personal characteristics of the respondents, as well as on community factors.