The black-breasted lark (Melanocorypha bimaculata), a pest of sorghum in Butana region, Gezira Province, Sudan

Attempts were made to investigate and account for some aspects of the present status of the black-breasted lark (Melanocorypha bimaculata) as a pest of sorghum in one of the rain-fed semi-desert areas of the Sudan. Also some observations were conducted to understand the behavior and the feeding habits of the pest in relation to crop damage phenology. Problems encountered in the application of some control techniques were discussed and evaluated in order to suggest sound control strategy

Farmers, seeds and varieties : supporting informal seed supply in Ethiopia

Ethiopia is characterized by an enormous diversity in agro-ecosystems, crops and varieties, with the informal seed systems dominant in seed supply for almost all crops. The book addresses strategies and approaches through which professionals can support informal seed supply, and links these with the conservation and use of the huge genetic resource base of crops and local varieties. The book looks at informal seed supply from a number of different angles, introduces key concepts and strategies, and presents case studies from Ethiopia and other countries. It deals with the technical aspects of, quality and availability of, and access to seed, and of supporting informal supply. It also deals with the role of farmers in the conservation and management of local crops and varieties, and the participation of farmers and communities in plant breeding and research. It takes a particular interest in the role of farmer organizations in seed supply, and how this role can be strengthened by developing community and small-scale seed enterprises. The aim of all the strategies, case studies and reflections on experiences presented in this book is to improve the availability of and access to quality seeds and varieties, thereby improving the livelihoods of small-scale farmers in Ethiopia and beyond

In utero seasonal food insecurity and cognitive development: Evidence from Ethiopia

Food insecurity is pervasive and highly seasonal in Ethiopia. In this study, we investigate the effect of seasonal food insecurity on child development. Exploiting the Young Lives Ethiopia dataset, we study the impact of in utero exposure to seasonal food insecurity on cognitive development for children of age 8 up to 12. We find that at age 8 in utero exposure to food insecurity shocks negatively, although insignificantly, affects cognitive development. But, at age 12, such exposure significantly reduces cognitive development. In utero exposure to seasonal food insecurity translates into a loss of 0.52 standard deviations in maths achievements score. Exposure during the first and second trimesters of pregnancy are found to have stronger detrimental effects. We also find stronger effects for boys

HIV-positive nigerian adults harbor significantly higher serum lumefantrine levels than HIV-negative individuals seven days after treatment for Plasmodium falciparum infection.

Management of coinfection with malaria and HIV is a major challenge to public health in developing countries, and yet potential drug-drug interactions between antimalarial and antiviral regimens have not been adequately investigated in people with both infections. Each of the constituent components of artemether-lumefantrine, the first-line regimen for malaria treatment in Nigeria, and nevirapine, a major component of highly active antiretroviral therapy, are drugs metabolized by the cytochrome P450 3A4 isoenzyme system, which is also known to be induced by nevirapine. We examined potential interactions between lumefantrine and nevirapine in 68 HIV-positive adults, all of whom were diagnosed with asymptomatic Plasmodium falciparum infections by microscopy. Post hoc PCR analysis confirmed the presence of P. falciparum in only a minority of participants. Day 7 capillary blood levels of lumefantrine were significantly higher in HIV-positive participants than in 99 HIV-negative controls (P = 0.0011). Associations between day 7 levels of lumefantrine and risk of persistent parasitemia could not be evaluated due to inadequate power. Further investigations of the impact of nevirapine on in vivo malaria treatment outcomes in HIV-infected patients are thus needed

Identifying Recrudescent Plasmodium falciparum in Treated Malaria Patients by Real-time PCR and High Resolution Melt Analysis of Genetic Diversity.

Recurrent parasitaemia during follow up of clinical trials of antimalarial drug efficacy results from either recrudescence of parasites surviving treatment or from parasites newly emerging from the hepatic stage of infection. Nested PCR is used to distinguish these two possibilities and the technique is difficult to standardise. There is risk of both false positive and false negative results, leading to misclassification errors. The high-resolution melt (HRM) assay was developed with pairs of conserved primers targeting blocks of merozoite surface protein 1 and 2 (msp1 and msp2) genes, and polymorphisms were compared using sequence-confirmed Plasmodium falciparum DNA samples from laboratory isolates. In this study, the HRM dissociation profiles of msp1 and msp2 amplicons were determined and validated against parasite isolates from malaria patients. The msp1 and msp2 profiles of both laboratory and clinical isolates were reproducibly differentiated by HRM. These rapid assays are performed in a closed-tube system, and so avoid cross-contamination while increasing throughput, which are two major advantages. The HRM assays offer significant gains in simplicity, speed and interpretation of results, and reduced analysis cost, for studies that require discrimination of parasite clones. Assay performance in large-scale studies utilizing DNA samples derived from filter-paper bloodspots should now be evaluated

Lack of K13 mutations in Plasmodium falciparum persisting after artemisinin combination therapy treatment of Kenyan children.

BACKGROUND: Studies in Southeast Asia reported a strong relationship between polymorphisms at the propeller domain of the Kelch 13 (K13) protein encoded by the Plasmodium falciparum k13 (pfk13) gene and delayed parasite clearance after artemisinin treatment. In Africa, P. falciparum remains susceptible and combination therapy regimens which include an artemisinin component display good efficacy. Using quantitative real-time PCR (qPCR), sub-microscopic persistence of P. falciparum has previously been reported in one-third of children treated with artemisinin combination therapy (ACT) in western Kenya. In this study, further investigation was made to evaluate whether these sub-microscopic residual parasites also harbour mutations at the propeller region of pfk13 and whether the mutations, if any, affect treatment outcome. METHODS: The pfk13 propeller domain was genotyped in DNA samples obtained in 2009 from Kenyan children treated with artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP). Paired samples at pre-treatment (day 0) and day of treatment failure (day 28 or 42) for 32 patients with documented recurrent parasitaemia were available for genotyping. Additional day 3 DNA samples were available for 10 patients. RESULTS: No mutation associated with artemisinin resistance in Southeast Asia was observed. Only one DP-treated patient harboured a non-synonymous mutation at codon 578 (A578S) of pfk13-propeller gene in the day 0 sample, but this allele was replaced by the wild-type (A578) form on day 3 and on the day of recurrent parasitaemia. The mutation at amino acid codon 578 showed no association with any phenotype. Polymorphisms in pfk13 were not responsible for parasite persistence and gametocyte carriage in the children treated with ACT. CONCLUSION: This study contributes to the ongoing surveillance of suspected artemisinin resistance parasites in Africa by providing baseline prevalence of k13-propeller mutations in western Kenya with samples collected from a longitudinal study. Clinical Trials Registration NCT00868465

Off-line Survivable Impairment-aware Routing and Wavelength Assignment

Physical impairments caused by noise and signal distortions affect the quality of an optical signal. The effect of physical impairments becomes more significant with an increase in distance and bit rates. In order to minimize the bit error rate (BER), an optical signal may need to be regenerated after a certai

Contribution of Plasmodium knowlesi to Multispecies Human Malaria Infections in North Sumatera, Indonesia.

Background: As Indonesia works toward the goal of malaria elimination, information is lacking on malaria epidemiology from some western provinces. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in 3 communities in North Sumatera Province. Methods: A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat, and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified using nested polymerase chain reaction (PCR) of ribosomal RNA genes and a novel assay that amplifies a conserved sequence specific for the sicavar gene family of Plasmodium knowlesi. Results: Of 3731 participants, 614 (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1169 individuals (31.3%). In total, 377 participants (11.8%) harbored P. knowlesi. Also present were Plasmodium vivax (14.3%), Plasmodium falciparum (10.5%) and Plasmodium malariae (3.4%). Conclusions: Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multispecies parasitemia is relatively common in North Sumatera, so PCR-based surveillance is required to support control and elimination activities

Delayed Onset of Symptoms and Atovaquone-Proguanil Chemoprophylaxis Breakthrough by Plasmodium malariae in the Absence of Mutation at Codon 268 of pmcytb.

Plasmodium malariae is widely distributed across the tropics, causing symptomatic malaria in humans with a 72-hour fever periodicity, and may present after latency periods lasting up to many decades. Delayed occurrence of symptoms is observed in humans using chemoprophylaxis, or patients having received therapies targeting P. falciparum intraerythrocytic asexual stages, but few investigators have addressed the biological basis of the ability of P. malariae to persist in the human host. To investigate these interesting features of P. malariae epidemiology, we assembled, here, an extensive case series of P. malariae malaria patients presenting in non-endemic China, Sweden, and the UK who returned from travel in endemic countries, mainly in Africa. Out of 378 evaluable P. malariae cases, 100 (26.2%) reported using at least partial chemoprophylaxis, resembling the pattern seen with the relapsing parasites P. ovale spp. and P. vivax. In contrast, for only 7.5% of imported UK cases of non-relapsing P. falciparum was any chemoprophylaxis use reported. Genotyping of parasites from six patients reporting use of atovaquone-proguanil chemoprophylaxis did not reveal mutations at codon 268 of the cytb locus of the P. malariae mitochondrial genome. While travellers with P. malariae malaria are significantly more likely to report prophylaxis use during endemic country travel than are those with P. falciparum infections, atovaquone-proguanil prophylaxis breakthrough was not associated with pmcytb mutations. These preliminary studies, together with consistent observations of the remarkable longevity of P. malariae, lead us to propose re-examination of the dogma that this species is not a relapsing parasite. Further studies are needed to investigate our favoured hypothesis, namely that P. malariae can initiate a latent hypnozoite developmental programme in the human hepatocyte: if validated this will explain the consistent observations of remarkable longevity of parasitism, even in the presence of antimalarial prophylaxis or treatment