Can we eradicate Cysticercosis?

International audiencepas de résum

Identifying Relapsing Fever Borrelia, Senegal

We describe a nested polymerase chain reaction for the identification of Borrelia species from serum of patients with unidentified fevers. This technique, based on single nucleotide polymorphisms of the 16S ribosomal RNA gene, was used to test blood samples from 7,750 patients, 33 of whom were diagnosed with spirochete infections. Borrelia crocidurae was the only species identified

Taenia solium cysticercosis in West Africa: status update

Cysticercosis is caused by the larvae of the cestode Taenia solium. Few data are available on the prevalence of this disease in pigs and humans in West African countries. The aim of this study was to provide an overview of existing data concerning the spread of this parasitosis in the countries of the Economic Community of West African States (ECOWAS) on the basis of the literature published over the last five decades. Systematic searches for publications were carried out on PubMed and Google Scholar, as well as in certain regional and local journals. From a total of 501 articles initially retrieved concerning T. solium cysticercosis in West African countries, only 120 articles were relevant for this review and therefore finally retained. For pigs, only eight out of sixteen countries of the region have reported porcine cysticercosis. Post-mortem examination of carcasses at slaughterhouses, meat inspection at butcheries or tongue inspection in herds have been the main source of data, but may not entirely reflect actual parasite distribution. For humans, only five out of sixteen countries reported epidemiological data on neurocysticercosis. Most data referred to neurocysticercosis prevalence among epileptic patients or isolated clinical cases. Furthermore, existing data are often old. Overall, T. solium cysticercosis remains largely neglected in West Africa, and its prevalence appears not to be affected by any religion in particular. There is an urgent need to promote and implement health partnerships and programs on this disease in order to collect more data and identify sensitive populations in the countries of the ECOWAS area

Chronic infection during placental malaria is associated with up-regulation of cycloxygenase-2

<p>Abstract</p> <p>Background</p> <p>Placental malaria (PM) is associated with poor foetal development, but the pathophysiological processes involved are poorly understood. Cyclooxygenase (COX) and lipoxygenase (LOX) which convert fatty acids to prostaglandins and leukotrienes, play important roles in pregnancy and foetal development. COX-2, currently targeted by specific drugs, plays a dual role as it associates with both pre-eclampsia pathology and recovery during infection. The role of COX during PM was questioned by quantifying at delivery COX-1, COX-2, 15-LOX, and IL-10 expression in two groups of malaria infected and uninfected placenta.</p> <p>Methods</p> <p>Placental biopsies were collected at delivery for mRNA isolation and quantification, using real time PCR.</p> <p>Results</p> <p>COX-2 and IL-10 mRNAs increased mainly during chronic infections (nine- and five-times, respectively), whereas COX-1 transcripts remained constant. COX-2 over-expression was associated with a higher birth weight of the baby, but with a lower rate of haemoglobin of the mother. It was associated with a macrophage infiltration of the placenta and with a low haemozoin infiltration. In the opposite way, placental infection was associated with lower expression of 15-LOX mRNA. A high degree of haemozoin deposition correlates with low birth weight and decreased expression of COX-2.</p> <p>Conclusion</p> <p>These data provide evidence that COX-2 and IL-10 are highly induced during chronic infection of the placenta, but were not associated with preterm delivery or low birth weight. The data support the involvement of COX-2 in the recovery phase of the placental infection.</p

Prevalence of Mutations in the \u3ci\u3ePfdhfr\u3c/i\u3e, \u3ci\u3ePfdhps\u3c/i\u3e, and \u3ci\u3ePfmdr1\u3c/i\u3e Genes of Malarial Parasites Isolated from Symptomatic Patients in Dogondoutchi, Niger

The effectiveness of artemisinin-based combination therapies (ACTs) depends not only on that of artemisinin but also on that of partner molecules. This study aims to evaluate the prevalence of mutations in the Pfdhfr, Pfdhps, and Pfmdr1 genes from isolates collected during a clinical study. Plasmodium genomic DNA samples extracted from symptomatic malaria patients from Dogondoutchi, Niger, were sequenced by the Sanger method to determine mutations in the Pfdhfr (codons 51, 59, 108, and 164), Pfdhps (codons 436, 437, 540, 581, and 613), and Pfmdr1 (codons 86, 184, 1034, and 1246) genes. One hundred fifty-five (155) pre-treatment samples were sequenced for the Pfdhfr, Pfdhps, and Pfmdr1 genes. A high prevalence of mutations in the Pfdhfr gene was observed at the level of the N51I (84.97%), C59R (92.62%), and S108N (97.39%) codons. The key K540E mutation in the Pfdhps gene was not observed. Only one isolate was found to harbor a mutation at codon I431V. The most common mutation on the Pfmdr1 gene was Y184F in 71.43% of the mutations found, followed by N86Y in 10.20%. The triple-mutant haplotype N51I/C59R/S108N (IRN) was detected in 97% of the samples. Single-mutant (ICS and NCN) and double-mutant (IRS, NRN, and ICN) haplotypes were prevalent at 97% and 95%, respectively. Double-mutant haplotypes of the Pfdhps (581 and 613) and Pfmdr (86 and 184) were found in 3% and 25.45% of the isolates studied, respectively. The study focused on the molecular analysis of the sequencing of the Pfdhfr, Pfdhps, and Pfmdr1 genes. Although a high prevalence of mutations in the Pfdhfr gene have been observed, there is a lack of sulfadoxine pyrimethamine resistance. There is a high prevalence of mutation in the Pfmdr184 codon associated with resistance to amodiaquine. These data will be used by Niger’s National Malaria Control Program to better monitor the resistance of Plasmodium to partner molecules in artemisinin-based combination therapies

Invasion of Africa by a single pfcrt allele of South East Asian type

BACKGROUND: Because of its dramatic public health impact, Plasmodium falciparum resistance to chloroquine (CQ) has been documented early on. Chloroquine-resistance (CQR) emerged in the late 1950's independently in South East Asia and South America and progressively spread over all malaria areas. CQR was reported in East Africa in the 1970's, and has since invaded the African continent. Many questions remain about the actual selection and spreading process of CQR parasites, and about the evolution of the ancestral mutant gene(s) during spreading. METHODS: Eleven clinical isolates of P. falciparum from Cambodia and 238 from Africa (Senegal, Ivory Coast, Bukina Faso, Mali, Guinea, Togo, Benin, Niger, Congo, Madagascar, Comoros Islands, Tanzania, Kenya, Mozambique, Cameroun, Gabon) were collected during active case detection surveys carried out between 1996 and 2001. Parasite DNA was extracted from frozen blood aliquots and amplification of the gene pfcrt exon 2 (codon 72–76), exon 4 and intron 4 (codon 220 and microsatellite marker) were performed. All fragments were sequenced. RESULTS: 124 isolates with a sensitive (c76/c220:CVMNK/A) haplotype and 125 isolates with a resistant c76/c220:CVIET/S haplotype were found. The microsatellite showed 17 different types in the isolates carrying the c76/c220:CVMNK/A haplotype while all 125 isolates with a CVIET/S haplotype but two had a single microsatellite type, namely (TAAA)3(TA)15, whatever the location or time of collection. CONCLUSION: Those results are consistent with the migration of a single ancestral pfcrt CQR allele from Asia to Africa. This is related to the importance of PFCRT in the fitness of P. falciparum point out this protein as a potential target for developments of new antimalarial drugs

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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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).</p> <p>Results</p> <p>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 <it>Plasmodia </it>that infect humans were also found: <it>Plasmodium falciparum</it>; <it>Plasmodium vivax</it>, <it>Plasmodium malariae </it>and <it>Plasmodium ovale</it>. 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. <it>P. falciparum </it>malaria has been predominant (98%). The high prevalence of <it>P. falciparum </it>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 <it>P. falciparum </it>per annum. Moreover, estimated incidence of <it>P. falciparum </it>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.</p> <p>Conclusion</p> <p>The incidence of malaria decreased slightly with age but remained important among children and adults in Saharevo. These results support that a premunition against malaria is slowly acquired until adolescence. However, this claims for a weak premunition among villagers in Saharevo and by extension in the whole eastern foothill area of Madagascar. While the Malagasy government turns towards malaria elimination plans nowadays, choices and expectations to up-date and adapt malaria control strategies in the foothill areas are discussed in this paper.</p

In vitro culture of Plasmodium berghei-ANKA maintains infectivity of mouse erythrocytes inducing cerebral malaria

<p>Abstract</p> <p>Background</p> <p>Infection with <it>Plasmodium berghei </it>is a widely used model of murine malaria and a powerful tool for reverse genetic and pathogenesis studies. However, the efficacy of <it>in vitro </it>reinvasion of erythrocytes is generally low, limiting <it>in vitro </it>studies.</p> <p>Methods</p> <p><it>Plasmodium berghei </it>ANKA-infected blood obtained from a susceptible infected mouse was cultured in various conditions and <it>in vitro </it>parasitaemia was measured every day to evaluate the rate of reinvasion.</p> <p>Results</p> <p>High quality culture media were used and reinvasion rates were improved by vigorous orbital shaking of the flask and increasing density of the medium with gelatin.</p> <p>Discussion</p> <p>Using these settings, reinvasion of normal mouse erythrocytes by the parasite was obtained <it>in vitro </it>over two weeks with preservation of the infectivity <it>in vivo</it>.</p