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Schotte U, Hoffmann T, Schwarz NG, Rojak S, Lusingu J, Minja D, Kaseka J, Mbwana J, Gesase S, May J, Dekker D, Frickmann H. Study of enteric pathogens among children in the tropics and effects of prolonged storage of stool samples. Lett Appl Microbiol 2021; 72:774-782. [PMID: 33544912 DOI: 10.1111/lam.13457] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/13/2021] [Accepted: 01/28/2021] [Indexed: 12/11/2022]
Abstract
The study was performed to compare real-time PCR after nucleic acid extraction directly from stool samples as well as from samples stored and transported on Whatman papers or flocked swabs at ambient temperature in the tropics. In addition, the possible suitability for a clear determination of likely aetiological relevance of PCR-based pathogen detections based on cycle threshold (Ct) values was assessed. From 632 Tanzanian children <5 years of age with and without gastrointestinal symptoms, 466 samples were subjected to nucleic acid extraction and real-time PCR for gastrointestinal viral, bacterial and protozoan pathogens. Equal or even higher frequencies of pathogen detections from Whatman papers or flocked swabs were achieved compared with nucleic acid extraction directly from stool samples. Comparison of the Ct values showed no significant difference according to the nucleic acid extraction strategy. Also, the Ct values did not allow a decision whether a detected pathogen was associated with gastrointestinal symptoms.
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Affiliation(s)
- U Schotte
- Department A - Veterinary Medicine, Central Institute of the Bundeswehr Medical Service Kiel, Kronshagen, Germany
| | - T Hoffmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - N G Schwarz
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine Hamburg, Hamburg, Germany
| | - S Rojak
- Department of Microbiology and Hospital Hygiene, Bundeswehr Central Hospital Koblenz, Koblenz, Germany
| | - J Lusingu
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - D Minja
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - J Kaseka
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - J Mbwana
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - S Gesase
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - J May
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine Hamburg, Hamburg, Germany
| | - D Dekker
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine Hamburg, Hamburg, Germany
| | - H Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Department of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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Boström S, Schmiegelow C, Abu Abed U, Minja DTR, Lusingu J, Brinkmann V, Honkpehedji YJ, Loembe MM, Adegnika AA, Mordmüller B, Troye-Blomberg M, Amulic B. Neutrophil alterations in pregnancy-associated malaria and induction of neutrophil chemotaxis by Plasmodium falciparum. Parasite Immunol 2017; 39. [PMID: 28380252 DOI: 10.1111/pim.12433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/31/2017] [Indexed: 11/27/2022]
Abstract
Pregnancy-associated malaria (PAM) is a severe form of the disease caused by sequestration of Plasmodium falciparum-infected red blood cells (iRBCs) in the developing placenta. Pathogenesis of PAM is partially based on immunopathology, with frequent monocyte infiltration into the placenta. Neutrophils are abundant blood cells that are essential for immune defence but may also cause inflammatory pathology. Their role in PAM remains unclear. We analysed neutrophil alterations in the context of PAM to better understand their contribution to disease development. Pregnant women exposed to Plasmodium falciparum had decreased numbers of circulating neutrophils. Placental-like BeWo cells stimulated with malaria parasites produced the neutrophil chemoattractant IL-8 and recruited neutrophils in a trans-well assay. Finally, immunostaining of a PAM placenta confirmed neutrophil accumulation in the intervillous space. Our data indicate neutrophils may play a role in placental malaria and should be more closely examined as an etiological agent in the pathophysiology of disease.
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Affiliation(s)
- S Boström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - C Schmiegelow
- Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - U Abu Abed
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - D T R Minja
- National Institute for Medical Research, Tanga, Tanzania
| | - J Lusingu
- National Institute for Medical Research, Tanga, Tanzania
| | - V Brinkmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Y J Honkpehedji
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Institute of Tropical Medicine, University of Tübingen and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - M M Loembe
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Institute of Tropical Medicine, University of Tübingen and German Center for Infection Research, partner site Tübingen, Tübingen, Germany.,Département de Bactério-Virologie, Université des Sciences de la Santé, Libreville, Gabon
| | - A A Adegnika
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Institute of Tropical Medicine, University of Tübingen and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - B Mordmüller
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Institute of Tropical Medicine, University of Tübingen and German Center for Infection Research, partner site Tübingen, Tübingen, Germany
| | - M Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - B Amulic
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
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Neafsey DE, Juraska M, Bedford T, Benkeser D, Valim C, Griggs A, Lievens M, Abdulla S, Adjei S, Agbenyega T, Agnandji ST, Aide P, Anderson S, Ansong D, Aponte JJ, Asante KP, Bejon P, Birkett AJ, Bruls M, Connolly KM, D'Alessandro U, Dobaño C, Gesase S, Greenwood B, Grimsby J, Tinto H, Hamel MJ, Hoffman I, Kamthunzi P, Kariuki S, Kremsner PG, Leach A, Lell B, Lennon NJ, Lusingu J, Marsh K, Martinson F, Molel JT, Moss EL, Njuguna P, Ockenhouse CF, Ogutu BR, Otieno W, Otieno L, Otieno K, Owusu-Agyei S, Park DJ, Pellé K, Robbins D, Russ C, Ryan EM, Sacarlal J, Sogoloff B, Sorgho H, Tanner M, Theander T, Valea I, Volkman SK, Yu Q, Lapierre D, Birren BW, Gilbert PB, Wirth DF. Genetic Diversity and Protective Efficacy of the RTS,S/AS01 Malaria Vaccine. N Engl J Med 2015; 373:2025-2037. [PMID: 26488565 PMCID: PMC4762279 DOI: 10.1056/nejmoa1505819] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus. METHODS We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination. RESULTS In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy. CONCLUSIONS These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).
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Drakeley CJ, Corran PH, Coleman PG, Tongren JE, McDonald SLR, Carneiro I, Malima R, Lusingu J, Manjurano A, Nkya WMM, Lemnge MM, Cox J, Reyburn H, Riley EM. Estimating medium- and long-term trends in malaria transmission by using serological markers of malaria exposure. Proc Natl Acad Sci U S A 2005; 102:5108-13. [PMID: 15792998 PMCID: PMC555970 DOI: 10.1073/pnas.0408725102] [Citation(s) in RCA: 387] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The implementation and evaluation of malaria control programs would be greatly facilitated by new tools for the rapid assessment of malaria transmission intensity. Because acquisition and maintenance of antimalarial antibodies depend on exposure to malaria infection, such antibodies might be used as proxy measures of transmission intensity. We have compared the prevalence of IgG antibodies with three Plasmodium falciparum asexual stage antigens in individuals of all ages living at varying altitudes encompassing a range of transmission intensities from hyper- to hypoendemic in northeastern Tanzania, with alternative measures of transmission intensity. The prevalence of antibodies to merozoite surface protein-1(19) was significantly more closely correlated with altitude than either point-prevalence malaria parasitemia or single measures of hemoglobin concentration. Analysis of age-specific seroprevalence rates enabled differentiation of recent (seasonal) changes in transmission intensity from longer-term transmission trends and, using a mathematical model of the annual rate of seroconversion, estimation of the longevity of the antibody response. Thus, serological tools allow us to detect variations in malaria transmission over time. Such tools will be invaluable for monitoring trends in malaria endemicity and the effectiveness of malaria control programs.
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Affiliation(s)
- C J Drakeley
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
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