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"Sannella, Anna R"
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Functional deficit of T regulatory cells in Fulani, an ethnic group with low susceptibility to Plasmodium falciparum malaria
2008
Previous interethnic comparative studies on the susceptibility to malaria performed in West Africa showed that Fulani are more resistant to Plasmodium falciparum malaria than are sympatric ethnic groups. This lower susceptibility is not associated to classic malaria-resistance genes, and the analysis of the immune response to P. falciparum sporozoite and blood stage antigens, as well as non-malaria antigens, revealed higher immune reactivity in Fulani. In the present study we compared the expression profile of a panel of genes involved in immune response in peripheral blood mononuclear cells (PBMC) from Fulani and sympatric Mossi from Burkina Faso. An increased expression of T helper 1 (TH1)-related genes (IL-18, IFNγ, and TBX21) and TH2-related genes (IL-4 and GATA3) and a reduced expression of genes distinctive of T regulatory activity (CTLA4 and FOXP3) were observed in Fulani. Microarray analysis on RNA from CD4⁺CD25⁺ (T regulatory) cells, performed with a panel of cDNA probes specific for 96 genes involved in immune modulation, indicated obvious differences between the two ethnic groups with 23% of genes, including TGFβ, TGFβRs, CTLA4, and FOXP3, less expressed in Fulani compared with Mossi and European donors not exposed to malaria. As further indications of a low T regulatory cell activity, Fulani showed lower serum levels of TGFβ and higher concentrations of the proinflammatory chemokines CXCL10 and CCL22 compared with Mossi; moreover, the proliferative response of Fulani to malaria antigens was not affected by the depletion of CD25⁺ regulatory cells whereas that of Mossi was significantly increased. The results suggest that the higher resistance to malaria of the Fulani could derive from a functional deficit of T regulatory cells.
Journal Article
Cryptosporidium Oocyst Contamination in Drinking Water: A Case Study in Italy
by
Sannella, Anna R.
,
Gilli, Giorgio
,
Bonetta, Silvia
in
Animals
,
Communication
,
Cryptosporidium - genetics
2019
The aim of this study was to evaluate the occurrence of Cryptosporidium oocysts in a drinking water treatment plant (DWTP) located in a rural area of northern Italy. Influent and effluent samples were collected at the DWTP over three years (2013–2016). In parallel, tap water samples from a public drinking fountain were collected as well. All samples were analyzed for the presence of Cryptosporidium spp. oocysts by a common method based on an immunomagnetic separation (IMS)/immunofluorescence assay (IFA), complemented by 4,6-diamidino-2-phenylindole (DAPI) staining. A reverse transcriptase-PCR (RT-PCR) protocol was added to evaluate oocyst viability. The results highlighted a high variability of oocyst concentrations across all samples (mean 4.3 ± 5.8/100 L) and a high variability in the percentage of DAPI-positive specimens (mean 48.2% ± 40.3%). Conversely, RT-PCR did not reveal the presence of viable C. parvum and C. hominis oocysts. A nested PCR targeting Cryptosporidium 18S ribosomal DNA, carried out in two water samples, confirmed the presence of a Cryptosporidium genotype associated with wild animals in the river and in tap water. The results obtained underline the vulnerability of the investigated surface water to Cryptosporidium spp. contamination. Although the recovered Cryptosporidium genotype is not a human pathogen, its presence demonstrates the existence of a potential pathogen Cryptosporidium spp. contamination risk. Moreover, these results underline the importance of also considering unconventional (not bacterial) biological contaminations (protozoa) in water resources in rural areas, including those of developed countries.
Journal Article
Psychological determinants of physical activity across the life course: A \DEterminants of DIet and Physical ACtivity\ (DEDIPAC) umbrella systematic literature review
2017
Low levels of physical activity (PA) are reported to contribute to the occurrence of non-communicable diseases over the life course. Although psychological factors have been identified as an important category concerning PA behavior, knowledge on psychological determinants of PA is still inconclusive. Therefore, the aim of this umbrella systematic literature review (SLR) was to summarize and synthesize the scientific evidence on psychological determinants of PA behavior across the life course. A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases. The search was limited to studies published in English from January 2004 to April 2016. SLRs and meta-analyses (MAs) of observational studies investigating the association of psychological variables and PA were considered eligible. Extracted data were evaluated based on importance of determinants, strength of evidence, and methodological quality. The full protocol is available from PROSPERO (Record ID: CRD42015010616). Twenty reviews (14 SLRs and 6 MAs), mostly of moderate methodological quality, were found eligible. Convincing evidence was found for self-efficacy (positive association with PA) in children and adolescents, and stress (negative association with PA) regardless of age. Most of the evidence revealing an association between psychological determinants and PA is probable and limited, mainly due to differences in the definition of PA and of psychological determinants across reviews. Thus, scholars are urged to reach a consensus on clear definitions of relevant psychological determinants of PA, subsuming cultural biases and allowing the possibility to obtain clear interpretations and generalizability of findings. Finally, most psychological determinants should be considered within a larger framework of other multi-level determinants that may interact or mediate some of the effects.
Journal Article
Behavioral determinants of physical activity across the life course: a “DEterminants of DIet and Physical ACtivity” (DEDIPAC) umbrella systematic literature review
by
Issartel, Johann
,
Carlin, Angela
,
Buck, Christoph
in
active transport
,
Adolescent
,
Adolescent Behavior
2017
Background
Low levels of physical activity (PA) are a global concern and increasing PA engagement is becoming a priority in current public health policies. Despite the large number of studies and reviews available, the evidence regarding the behavioral determinants of PA is still inconclusive. Thus, the aim of this umbrella systematic literature review (SLR) was to summarize the evidence on the behavioral determinants of PA across the life course.
Methods
A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases. The search was limited to studies published in English from January, 2004 to April, 2016. SLRs and meta-analyses (MAs) of observational studies that investigated the behavioral determinants of PA were considered eligible. The extracted data were assessed based on the importance of the determinants, the strength of evidence, and the methodological quality. The full protocol is available from PROSPERO (PROSPERO 2014:CRD42015010616).
Results
Seventeen reviews on 35 behavioral determinants of PA were eligible for this umbrella SLR. Regardless of age, the most investigated determinants were those related with ‘screen use’ and ‘smoking’. For youth, probable positive evidence emerged for ‘previous PA’ and ‘independent mobility and active transport’ among children and adolescents. For the adult population, ‘transition to university’ and ‘pregnancy/having a child’ showed probable negative associations.
Conclusions
Although the majority of the evidence was limited and most of the determinants were not associated with PA, this umbrella SLR provided a comprehensive overview of the associations between behavioral determinants and PA. Youth should be physically active in the early years and increase active transportation to/from school, independent mobility, and ‘free-range activities’ without adult supervision, whilst adult PA behaviors are mostly influenced by the life events. Finally, more research is needed that incorporates prospective study designs, standardized definitions of PA, objective measurement methods of PA assessment, and the use of interactionist and mediational approaches for the evaluation of different behavioral determinants influencing PA behaviors.
Journal Article
Evolutionary epidemiology of a zoonosis
by
Anna Rosa Sannella
,
Asnicar, Francesco
,
Segata, Nicola
in
Diarrhea
,
Epidemiology
,
Evolutionary Biology
2021
Cryptosporidium parvum is a global zoonoses and a major cause of diarrhoea in humans and ruminants. The parasite's life cycle comprises an obligatory sexual phase, during which genetic exchanges can occur between previously isolated lineages. Here, we compare 32 whole genome sequences from human- and ruminant-derived parasite isolates collected across Europe, Egypt and China. We identify three strongly supported clusters that comprise a mix of isolates from different host species, geographic origins, and subtypes. We show that: (1) recombination occurs between ruminant isolates into human isolates; (2) these recombinant regions can be passed on to other human subtypes through gene flow and population admixture; (3) there have been multiple genetic exchanges, and all are likely recent; (4) putative virulence genes are significantly enriched within these genetic exchanges, and (5) this results in an increase in their nucleotide diversity. We carefully dissect the phylogenetic sequence of two genetic exchanges, illustrating the long-term evolutionary consequences of these events. Our results suggest that increased globalisation and close human-animal contacts increase the opportunity for genetic exchanges between previously isolated parasite lineages, resulting in spillover and spillback events. We discuss how this can provide a novel substrate for natural selection at genes involved in host-parasite interactions, thereby potentially altering the dynamic coevolutionary equilibrium in the Red Queens arms race. Competing Interest Statement The authors have declared no competing interest.