Argas ticks (Ixodida: Argasidae) on migratory birds from Africa: first record of a genotype close to Argas africolumbae in Italy.

In spring, migratory birds reach Europe, mainly from sub-Saharan Africa or from northern African countries. Avian species may be implicated in the spread of pathogens, either as reservoirs, hosts or carriers of infected ectoparasites. In 2021, on Ventotene Island (Latium region, Italy) within a project focused on the potential incoming pathogens via migratory birds from Africa, we found two larvae of Argas sp., on the redstart Phoenicurus phoenicurus, that shared morphological features with the African Argas (Argas) africolumbae. Comparison of the tested larval DNA sequences to the adult reference sequences showed the highest identity (> 92%) with homologous sequences of A. africolumbae collected in South Africa and in Spain. This study reports the first detection of Argas africolumbae-like specimens in Italy.

Tick species from Africa by migratory birds: a 3-year study in Italy.

The role of resident or migratory birds in dispersal of tick species and tick-borne pathogens is still poorly known in Italy. We report here the results of a 3-year project based on sampling ticks from migratory birds, as well as from the vegetation at three stop-over sites for migrants, namely the islands of Ventotene (Latium), Asinara (Sardinia) and Ustica (Sicily). During the spring seasons from 2017-2019, in total 2681 ticks were collected, 2344 of which were sampled from migratory birds and 337 from the vegetation. Ticks were identified by morphology or by molecular tools when necessary. In total, 16 tick species were identified among which the following were exclusively found on birds: Hyalomma rufipes (43.3%), Hy. truncatum (0.1%), Ixodes frontalis (11.8%), Ix. inopinatus (0.2%), Ix. ricinus (3%), Haemaphysalis punctata (0.08%), Hae. erinacei (0.1%), Amblyomma variegatum (0.08%) and Argas vulgaris 0.1%), whereas five species were exclusively collected from the vegetation: Rhipicephalus bursa (10.5%), Rh. turanicus (5.9%), Rh. sanguineus sensu lato (2%), Rh. pusillus (2.4%), Hae. sulcata (0.08%). Hy. marginatum (10.3%) and Ix. ventalloi (9.3%) were found both on birds and on the vegetation on the island Ustica. It is worth noting that the search for ticks on the vegetation did not detect allochthonous tick species. Although we found several interesting local species and allochthonous ticks like Hy. rufipes, Am. variegatum and Ar. vulgaris on birds, further investigations are needed to better define the possible role of migratory birds in the introduction of ticks and tick-borne diseases in Italy, above all after the evidence of imported ticks positive to Crimean Congo hemorrhagic fever (CCHF) virus in several European countries.

The genus Atheris (Serpentes: Viperidae) in East Africa: phylogeny and the role of rifting and climate in shaping the current pattern of species diversity.

Past climatic and tectonic events are believed to have strongly influenced species diversity in the Eastern Afromontane Biodiversity Hotspot. We investigated the phylogenetic relationships and historical biogeography of the East African genus Atheris (Serpentes: Viperidae), and explored temporal and spatial relationships between Atheris species across Africa, and the impact of palaeoclimatic fluctuations and tectonic movements on cladogenesis of the genus. Using mitochondrial sequence data, the phylogeny of East African species of Atheris shows congruent temporal patterns that link diversification to major tectonic and aridification events within East Africa over the last 15million years (my). Our results are consistent with a scenario of a delayed direct west-east colonisation of the Eastern Arc Mountains of Atheris by the formation of the western rift. Based on the phylogenetic patterns, this terrestrial, forest-associated genus has dispersed into East Africa across a divided route, on both west-southeasterly and west-northeasterly directions (a C-shaped route). Cladogenesis in the Eastern Arc Mountains and Southern Highlands of Tanzania corresponds to late Miocene and Plio-Pleistocene climatic shifts. Taxonomically, our data confirmed the monophyly of Atheris as currently defined, and reveal four major East African clades, three of which occur in discrete mountain ranges. Possible cryptic taxa are identified in the Atheris rungweensis and A. ceratophora clades.

Probable autochthonous introduced malaria cases in Italy in 2009-2011 and the risk of local vector-borne transmission.

We describe two cases of probable autochthonous introduced Plasmodium vivax malaria that occurred in 2009 and 2011 in two sites of South-Central Italy. Although the sources of the infections were not detected, local transmission could not be disproved and therefore the cases were classified as autochthonous. Sporadic P. vivax cases transmitted by indigenous vectors may be considered possible in some areas of the country where vector abundance and environmental conditions are favourable to malaria transmission.

Characterization of the metacaspase 1 gene in Plasmodium vivax field isolates from southern Iran and Italian imported cases.

Plasmodium vivax is still the more prevalent human Plasmodium outside Africa and despite this fact, there is still a deep lack of knowledge on its biology. Metacaspases are cysteine proteases related to metazoan caspases, involved in programmed cell death. Here, we have characterized the P. vivax metacaspase 1 gene in a total of 63 vivax isolates, 32 isolates collected in southern Iran and 31 Italian imported isolates originating from 12 different endemic countries. We have firstly identified DNA size polymorphism in P. vivax metacaspase 1 gene. A total of four different allelic sizes were found, resulting from the insertion of 1 to 4 tandem repeat units located within the intronic region of the P. vivax metacaspase 1. Similarly, we also have identified four distinct allelic types by using vivax merozoite surface protein-1 size polymorphism analysis.

Meager genetic variability of the human malaria agent Plasmodium vivax.

Malaria is a major human parasitic disease caused by four species of Plasmodium protozoa. Plasmodium vivax, the most widespread, affects millions of people across Africa, Asia, the Middle East, and Central and South America. We have studied the genetic variability of 13 microsatellite loci in 108 samples from 8 localities in Asia, Africa, South America, and New Guinea. Only one locus is polymorphic; nine are completely monomorphic, and the remaining three are monomorphic in all but one or two populations, which have a rare second allele. In contrast, Plasmodium falciparum displays extensive microsatellite polymorphism within and among populations. We further have analyzed, in 96 samples from the same 8 localities, 8 tandem repeats (TRs) located on a 100-kb contiguous chromosome segment described as highly polymorphic. Each locus exhibits 2-10 alleles in the whole sample but little intrapopulation polymorphism (1-5 alleles with a prevailing allele in most cases). Eight microsatellite loci monomorphic in P. vivax are polymorphic in three of five Plasmodium species related to P. vivax (two to seven individuals sampled). Plasmodium simium, a parasite of New World monkeys, is genetically indistinguishable from P. vivax. At 13 microsatellite loci and at 7 of the 8 TRs, both species share the same (or most common) allele. Scarce microsatellite polymorphism may reflect selective sweeps or population bottlenecks in recent evolutionary history of P. vivax; the differential variability of the TRs may reflect selective processes acting on particular regions of the genome. We infer that the world expansion of P. vivax as a human parasite occurred recently, perhaps <10,000 years ago.

Cellular localization and functional role of phosphatidylcholine-specific phospholipase C in NK cells.

Although several classes of phospholipases have been implicated in NK cell-mediated cytotoxicity, no evidence has been reported to date on involvement of phosphatidylcholine-specific phospholipase C (PC-PLC) in NK activation by lymphokines and/or in lytic granule exocytosis. This study demonstrated the expression of two PC-PLC isoforms (M(r) 40 and 66 kDa) and their IL-2-dependent distribution between cytoplasm and ectoplasmic membrane surface in human NK cells. Following cell activation by IL-2, cytoplasmic PC-PLC translocated from the microtubule-organizing center toward cell periphery, essentially by kinesin-supported transport along microtubules, while PC-PLC exposed on the outer cell surface increased 2-fold. Preincubation of NK cells with a PC-PLC inhibitor, tricyclodecan-9-yl-xanthogenate, strongly reduced NK-mediated cytotoxicity. In IL-2-activated cells, this loss of cytotoxicity was associated with a decrease of PC-PLC exposed on the cell surface, and accumulation of cytoplasmic PC-PLC in the Golgi region. Massive colocalization of PC-PLC-rich particles with perforin-containing granules was found in the cytoplasm of NK-activated (but not NK-resting) cells; both organelles clustered at the intercellular contact region of effector-target cell conjugates. These newly detected mechanisms of PC-PLC translocation and function support an essential role of this enzyme in regulated granule exocytosis and NK-mediated cytotoxicity.

Genotyping of Plasmodium falciparum gametocytes by reverse transcriptase polymerase chain reaction.

A molecular assay has been developed for the specific detection and genetic characterisation of Plasmodium falciparum gametocytes in the blood of malaria infected individuals. The assay is based on the reverse transcription and polymerase chain reaction (RT-PCR) amplification of the messenger RNA of gene pfg377, a sexual-stage specific transcript abundantly produced in maturing gametocytes. The gene contains four regions of repetitive sequences, of which region 3 was shown to be the most polymorphic in laboratory clones and field isolates of the parasite. Analysis of samples of malaria infected blood by RT-PCR specific for region 3 has enabled identification of multiple gametocyte-producing clones within single infections. The assay is able to detect gametocytes below the threshold of microscopic detection, and is highly specific for its gametocyte targets also in the presence of a vast excess of asexual forms.

Factor V leiden increases plasma F1+2 levels both in normal and deep venous thrombosis subjects.

BACKGROUND AND OBJECTIVE: A simple approach to understanding molecular mechanisms leading to thrombosis is the definition of how genetic factors influence biochemical parameters of coagulation. Conflicting data have been reported regarding the role that the genotype of factor V plays in the control of plasma F1+2 levels. The aim of this study was to test whether the factor V Leiden mutation affects F1+2 levels. DESIGN AND METHODS: We studied the effect of factor V Leiden mutation (detected by the polymerase chain reaction technique) on plasma F1+2 levels in 418 normal subjects and 39 subjects affected by deep venous thrombosis. RESULTS: In both normal subjects and those with venous thrombosis, heterozygotes for the Leiden mutation showed significantly higher plasma levels of F1+2 (p<0.0001 and p<0.005, respectively). Subjects with venous thrombosis had a higher allelic frequency of the Leiden mutation than normal subjects (11.5% and 3.1%, respectively). INTERPRETATION AND CONCLUSIONS: The results indicate that the genotype of factor V is a determinant of plasma F1+2 concentration. The allelic frequency of Leiden mutation in our normal subjects is higher than that found in other Italian populations but similar to that reported for populations of north- and middle-Europe. This finding is consistent with the peculiar ancestry and history of Friuli (the area in which subjects for this study were recruited), with respect to other Italian regions.