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7 result(s) for "Sannella, Anna Rosa"
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First molecular investigation of Cryptosporidium spp. in young calves in Algeria
To date, no information is available on the prevalence and genetic identity of Cryptosporidium spp. in cattle in Algeria. In this study, 17 dairy farms in the province of Batna, located in the northeast of the country, were visited to collect 132 fecal samples from young calves (< 8 weeks old). Samples were examined microscopically using the modified Ziehl-Neelsen acid-fast staining method, and at least one sample per farm was submitted for molecular analysis. Amplification of a fragment of the small subunit ribosomal RNA gene was positive for 24 of the 61 samples (40%), and sequence analysis identified three species, namely Cryptosporidium bovis (n = 14), C. ryanae (n = 6), and C. parvum (n = 4). The C. parvum IIaA13G2R1 subtype, an uncommon zoonotic subtype, was identified in two isolates from a single farm by sequencing a fragment of the GP60 gene. This is the first report about genotyping and subtyping of Cryptosporidium in calves in Algeria.
A retrospective molecular study of Cryptosporidium species and genotypes in HIV-infected patients from Thailand
Background Opportunistic infections represent a serious health problem for HIV-infected people. Among enteric infections, cryptosporidiosis, a severe and life-threatening diarrheal disease, is of particular importance in low economic settings where access to anti-retroviral therapy is limited. Understanding transmission routes is crucial in establishing preventive measures, and requires the use of informative genotyping methods. In this study, we performed a retrospective analysis of Cryptosporidium species in 166 stool samples collected from 155 HIV-infected patients during 1999–2004 at the Siriraj Hospital in Bangkok, Thailand. Results Microscopic examination of stools identified 104 of the 155 patients as positive for Cryptosporidium . Other common pathogens identified were microsporidia, Isospora , Giardia , Strongyloides and Opisthorchis. All samples were tested by amplification of a fragment of the 18S rDNA locus, and sequencing showed the presence of Cryptosporidium hominis ( n  = 42), C. meleagridis ( n  = 20), C. canis ( n  = 12), C. felis ( n  = 7), C. suis ( n  = 6) and C. parvum ( n  = 5). Genotyping at the glycoprotein 60 ( gp60 ) locus revealed substantial variability in isolates of C. hominis and C. meleagridis . Among C. hominis isolates, subtype IeA11G3T3 was the most prevalent, but allelic family Id was the more diverse with four subtypes described, two of which were identified for the first time. Among C. meleagridis isolates, seven subtypes, two of which were new, were found in the allelic family IIIb, along with new subtypes in allelic families IIIe and IIIg. In the four C. parvum isolates, subtype IIoA16G1, a rare subtype previously reported in a Swedish patient who had traveled to Thailand, was identified. Conclusions This study confirms the high susceptibility of HIV-infected individuals to infection with different Cryptosporidium species and subtypes, and further stresses the importance of surveillance for opportunistic intestinal protozoans.
Three Cases of Human Babesiosis, Italy, 2017–2020
We report 3 cases of babesiosis in Italy caused by Babesia species that are rarely reported in humans. The circulation of Babesia spp. among vectors, animals, and humans might be more common than previously thought, and babesiosis might be an underdiagnosed and emerging disease in Italy and Europe.
Extensive testing of a multi-locus sequence typing scheme for Giardia duodenalis assemblage A confirms its good discriminatory power
Background The flagellated parasite Giardia duodenalis is a major and global cause of diarrhoeal disease. Eight genetically very distinct groups, known as assemblages A to H, have been recognized in the G. duodenalis species complex, two of which (assemblages A and B) infect humans and other mammalian hosts. Informative typing schemes are essential to understand transmission pathways, characterize outbreaks and trace zoonotic transmission. In this study, we evaluated a published multi-locus sequence typing (MLST) scheme for G. duodenalis assemblage A, which is based on six polymorphic markers. Methods We genotyped 60 human-derived and 11 animal-derived G. duodenalis isolates collected in Europe and on other continents based on the published protocol. After retrieving previously published genotyping data and excluding isolates whose sequences showed allelic sequence heterozygosity, we analysed a dataset comprising 146 isolates. Results We identified novel variants at five of the six markers and identified 78 distinct MLST types in the overall dataset. Phylogenetic interpretation of typing data confirmed that sub-assemblage AII only comprises human-derived isolates, whereas sub-assemblage AI comprises all animal-derived isolates and a few human-derived isolates, suggesting limited zoonotic transmission. Within sub-assemblage AII, isolates from two outbreaks, which occurred in Sweden and Italy, respectively, had unique and distinct MLST types. Population genetic analysis showed a lack of clustering by geographical origin of the isolates. Conclusion The MLST scheme evaluated provides sufficient discriminatory power for epidemiological studies of G. duodenalis assemblage A. Graphical Abstract
Specific tagging of the egress-related osmiophilic bodies in the gametocytes of Plasmodium falciparum
Background Gametocytes, the blood stages responsible for Plasmodium falciparum transmission, contain electron dense organelles, traditionally named osmiophilic bodies, that are believed to be involved in gamete egress from the host cell. In order to provide novel tools in the cellular and molecular studies of osmiophilic body biology, a P. falciparum transgenic line in which these organelles are specifically marked by a reporter protein was produced and characterized. Methodology A P. falciparum transgenic line expressing an 80-residue N-terminal fragment of the osmiophilic body protein Pfg377 fused to the reporter protein DsRed, under the control of pfg377 upstream and downstream regulatory regions, was produced. Results The transgenic fusion protein is expressed at the appropriate time and stage of sexual differentiation and is trafficked to osmiophilic bodies as the endogenous Pfg377 protein. These results indicate that a relatively small N-terminal portion of Pfg377 is sufficient to target the DsRed reporter to the gametocyte osmiophilic bodies. Conclusions This is the first identification of a P. falciparum aminoacid sequence able to mediate trafficking to such organelles. To fluorescently tag such poorly characterized organelles opens novel avenues in cellular and imaging studies on their biogenesis and on their role in gamete egress.
Evolutionary epidemiology of a zoonosis
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.
Comparative genomics reveals the emergence of an outbreak-associated Cryptosporidium parvum population in Europe and its spread to the USA
The zoonotic parasite Cryptosporidium parvum is a global cause of gastrointestinal disease in humans and ruminants. Sequence analysis of the highly polymorphic gp60 gene enabled the classification of C. parvum isolates into multiple groups (e.g. IIa, IIc, Id) and a large number of subtypes. In Europe, subtype IIaA15G2R1 is largely predominant and has been associated with many water-and food-borne outbreaks. In this study, we generated new whole genome sequence (WGS) data from 123 human-and ruminant-derived isolates collected in 13 European countries and included other available WGS data from Europe, Egypt, China and the USA (n=72) in the largest comparative genomics study to date. We applied rigorous filters to exclude mixed infections and analysed a dataset from 141 isolates from the zoonotic groups IIa (n=119) and IId (n=22). Based on 28,047 high quality, biallelic genomic SNPs, we identified three distinct and strongly supported populations: isolates from China (IId) and Egypt (IIa and IId) formed population 1, a minority of European isolates (IIa and IId) formed population 2, while the majority of European (IIa, including all IIaA15G2R1 isolates) and all isolates from the USA (IIa) clustered in population 3. Based on analyses of the population structure, population genetics and recombination, we show that population 3 has recently emerged and expanded throughout Europe to then, possibly from the UK, reach the USA where it also expanded. In addition, genetic exchanges between different populations led to the formation of mosaic genomes. The reason(s) for the successful spread of population 3 remained elusive, although genes under selective pressure uniquely in this population were identified.