Principal Host Research Articles

Unravelling the processes controlling apatite formation in the Phalaborwa Complex (South Africa) based on combined cathodoluminescence, LA-ICPMS and in-situ O and Sr isotope analyses

The Phalaborwa world-class phosphate deposit (South Africa) is hosted by a Paleoproterozoic alkaline complex mainly composed of phoscorite, carbonatite, pyroxenitic rocks, and subordinate fenite. In addition, syenite and trachyte occur in numerous satellite bodies. New petrological and in-situ geochemical data along with O and Sr isotope data obtained on apatite demonstrate that apatite is in the principal host rocks (pyroxenitic rocks, phoscorite and carbonatite) formed primarily by igneous processes from mantle-derived carbonatitic magmas. Early-formed magmatic apatite is particularly enriched in light rare earth elements (LREE), with a decrease in the REE content ascribed to magma differentiation and early apatite fractionation in isolated interstitial melt pockets. Rayleigh fractionation favored a slight increase in δ18O (below 1%) at a constant Sr isotopic composition. Intrusion of fresh carbonatitic magma into earlier-formed carbonatite bodies locally induced re-equilibration of early apatite with REE enrichment but at constant O and Sr isotopic compositions. In fenite, syenite and trachyte, apatite displays alteration textures and LREE depletion, reflecting interaction with fluids. A marked decrease in δ18O in apatite from syenite and trachyte indicates a contribution from δ18O-depleted meteoric fluids. This is consistent with the epizonal emplacement of the satellite bodies. The general increase of the Sr isotope ratios in apatite in these rocks reflects progressive interaction with the country rocks over time. This study made it possible to decipher, with unmatched precision, the succession of geological processes that led to one of the most important phosphate deposits worldwide.

Tracing cross species transmission of Mycobacterium bovis at the wildlife/livestock interface in South Africa

BackgroundBovine tuberculosis (bTB) affects cattle and wildlife in South Africa with the African buffalo (Syncerus caffer) as the principal maintenance host. The presence of a wildlife maintenance host at the wildlife/livestock interface acting as spill-over host makes it much more challenging to control and eradicate bTB in cattle. Spoligotyping and mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) genotyping methods were performed to investigate the genetic diversity of Mycobacterium bovis (M. bovis) isolates from cattle and wildlife, their distribution and transmission at the wildlife/livestock interface in northern Kwa-Zulu Natal (KZN), South Africa.ResultsSB0130 was identified as the dominant spoligotype pattern at this wildlife/livestock interface, while VNTR typing revealed a total of 29 VNTR profiles (strains) in the KZN province signifying high genetic variability. The detection of 5 VNTR profiles shared between cattle and buffalo suggests M. bovis transmission between species. MIRU-VNTR confirmed co-infection in one cow with three strains of M. bovis that differed at a single locus, with 2 being shared with buffalo, implying pathogen introduction from most probably unrelated wildlife sources.ConclusionOur findings highlight inter and intra species transmission of bTB at the wildlife/livestock interface and the need for the implementation of adequate bTB control measures to mitigate the spread of the pathogen responsible for economic losses and a public health threat.

Spittlebugs of Mediterranean Olive Groves: Host-Plant Exploitation throughout the Year.

Spittlebugs are the vectors of the bacterium Xylella fastidiosa Wells in Europe, the causal agent of olive dieback epidemic in Apulia, Italy. Selection and distribution of different spittlebug species on host-plants were investigated during field surveys in 2016–2018 in four olive orchards of Apulia and Liguria Regions of Italy. The nymphal population in the herbaceous cover was estimated using quadrat samplings. Adults were collected by sweeping net on three different vegetational components: herbaceous cover, olive canopy, and wild woody plants. Three species of spittlebugs were collected: Philaenus spumarius L., Neophilaenus campestris (Fallén), and Aphrophora alni (L.) (Hemiptera: Aphrophoridae). Philaenus spumarius was the predominant species both in Apulia and Liguria olive groves. Nymphal stages are highly polyphagous, selecting preferentially Asteraceae Fabaceae plant families, in particular some genera, e.g., Picris, Crepis, Sonchus, Bellis, Cichorium, and Medicago. Host-plant preference of nymphs varies according to the Region and through time and nymphal instar. In the monitored sites, adults peak on olive trees earlier in Apulia (i.e., during inflorescence emergence) than in Liguria (i.e., during flowering and beginning of fruit development). Principal alternative woody hosts are Quercus spp. and Pistacia spp. Knowledge concerning plant selection and ecological traits of spittlebugs in different Mediterranean olive production areas is needed to design effective and precise control strategies against X. fastidiosa vectors in olive groves, such as ground cover modifications to reduce populations of spittlebug vectors.

Ecology and Infection Dynamics of Multi-Host Amdoparvoviral and Protoparvoviral Carnivore Pathogens.

Amdoparvovirus and Protoparvovirus are monophyletic viral genera that infect carnivores. We performed surveillance for and sequence analyses of parvoviruses in mustelids in insular British Columbia to investigate parvoviral maintenance and cross-species transmission among wildlife. Overall, 19.1% (49/256) of the tested animals were parvovirus-positive. Aleutian mink disease virus (AMDV) was more prevalent in mink (41.6%, 32/77) than martens (3.1%, 4/130), feline panleukopenia virus (FPV) was more prevalent in otters (27.3%, 6/22) than mink (5.2%, 4/77) or martens (2.3%, 3/130), and canine parvovirus 2 (CPV-2) was found in one mink, one otter, and zero ermines (N = 27). Viruses were endemic and bottleneck events, founder effects, and genetic drift generated regional lineages. We identified two local closely related AMDV lineages, one CPV-2 lineage, and five FPV lineages. Highly similar viruses were identified in different hosts, demonstrating cross-species transmission. The likelihood for cross-species transmission differed among viruses and some species likely represented dead-end spillover hosts. We suggest that there are principal maintenance hosts (otters for FPV, raccoons for CPV-2/FPV, mink for AMDV) that enable viral persistence and serve as sources for other susceptible species. In this multi-host system, viral and host factors affect viral persistence and distribution, shaping parvoviral ecology and evolution, with implications for insular carnivore conservation.

Feeding performance on a novel host: no adaptation over generations and differential patterns in two flea species.

To model the colonization of a novel host by fleas, Synosternus cleopatrae and Xenopsylla ramesis, we established experimental lines maintained for 15 generations on a principal or a novel host (either co-occurring with a flea or not). We compared the blood meal size and the energy expended for digestion by fleas from the 15th generation of each line on these hosts between hosts within a line and between lines within a host asking (a) whether fleas adapt to a novel host (increased blood consumption/decreased energy expended for digestion); (b) if yes, whether this adaptation leads to the loss of ability to exploit an original host, and (c) whether the success of adaptation to a novel host depends on its ecological co-occurrence with a flea. The blood consumption and digestion energetics of fleas fed on the principal host differed from those on other hosts. The effect of the principal host on feeding performance differed between fleas, with S. cleopatrae consuming less blood and expending more energy for digestion on the principal than on any other host, whereas the opposite was true for X. ramesis. No changes in feeding performance on a novel host over generations were found. We propose several explanations for the lack of adaptation to a novel host over time. We explain the poor performance of S. cleopatrae on its principal host via its immune response mounting pattern. We argue that the principal host of a parasite is not necessarily the host on which the parasite demonstrates the best performance.

First detection of the Nearctic parasitoid species Trichopoda pennipes (Fabricius) (Diptera: Tachinidae) in Egypt

Specimens of the feather-legged fly, Trichopoda pennipes (Fabricius) (Diptera: Tachinidae), which parasitize adults of the southern green stink bug Nezara viridula (L.) (Hemiptera: Pentatomidae), have been detected in Giza, Egypt. This is the first record of this Nearctic species with its genus (Trichopoda) and its tribe (Gymnosomatini) in Egypt. T. pennipes is known as an endoparasitoid of many true bug hosts, the pests of various crops, and it could have a potentiality to control these pests in addition to N. viridula, which is known to be its principal host. Taxonomy and diagnosis of the detected parasitoid species in addition to a checklist of the subfamily Phasiinae in Egypt are provided. Colored photographs of the parasitoid larval and adult stages and parasitized host are provided as well.

Assessment of the modes of occurrence of trace elements in agricultural crop residues and their enrichments and bioavailability in bio-chars

This work investigates the modes of occurrence of trace elements in crop residues, their volatilities during pyrolysis, and bioavailability in bio-chars. Eight major elements (Na, K. Mg, Ca, Al, Si, Fe, and P) and 16 trace elements (Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Sr, Cd, Ba, and Pb) were determined. Many trace elements in the five crop residues (peanut straw, cotton straw, corn stalk, sorghum stalk, and reed) had higher concentrations than the average values of world reference plants, with significant correlations to specific major elements. Neutral extractives were a principal host of all of the trace elements detected. While hemicellulose and lignin contained some trace elements (Li, Be, V, Cr, Ni, and Ga), cellulose enclosed lesser trace elements, During the slow biomass pyrolysis at 550 °C, all trace elements except for highly volatile Se and Cd were concentrated in the bio-chars with the enrichment factors ranging in 1.6–2.9. Most trace elements in the bio-chars showed lower solubility in water but much higher dissolution in the ion-exchangeable or chelating solution. Results suggested that the bio-chars originated from crop residues can provide bioavailable nutrients as the essential elements for plants if used as an amendment of soils.

Endoparasitic fauna of two South American foxes in Chile: Lycalopex culpaeus and Lycalopex griseus.

Native foxes face serious threats related to anthropic activities and the uncontrolled pets. However, the transmission of several pathogens such as parasites by domestic dogs is an important conservation issue with limited attention in Chile. The lack of a proper identification of the helminths of wild canids in the country, based mostly in coprological studies, limited our knowledge in potential interspecific transmission. Thus, the aim of the present survey was to identify the parasitic fauna of two native canids, the Andean fox (Lycalopex culpaeus) (n=49) and Chilla (Lycalopex griseus) (n=17), from several localities in Chile through a complete parasitological survey. Sixteen different species were identified, 9 of which are new host records for Andean fox and two for Chilla fox in South America, and three are recorded for first time in Chile. Also, five of them are of zoonotic concern and six are known to use domestic dogs as their principal hosts. These findings have implications for public health and the conservation of canids whose interspecific transmission of parasites with domestic dogs is confirmed through these findings. The need for an exhaustive surveillance of wild carnivores is emphasized considering these hosts as important sources of micro- and macroparasites.

Continent-wide population genomic structure and phylogeography of North America's most destructive conifer defoliator, the spruce budworm (Choristoneura fumiferana).

The spruce budworm, Choristoneura fumiferana, is presumed to be panmictic across vast regions of North America. We examined the extent of panmixia by genotyping 3,650 single nucleotide polymorphism (SNP) loci in 1975 individuals from 128 collections across the continent. We found three spatially structured subpopulations: Western (Alaska, Yukon), Central (southeastern Yukon to the Manitoba–Ontario border), and Eastern (Manitoba–Ontario border to the Atlantic). Additionally, the most diagnostic genetic differentiation between the Central and Eastern subpopulations was chromosomally restricted to a single block of SNPs that may constitute an island of differentiation within the species. Geographic differentiation in the spruce budworm parallels that of its principal larval host, white spruce (Picea glauca), providing evidence that spruce budworm and spruce trees survived in the Beringian refugium through the Last Glacial Maximum and that at least two isolated spruce budworm populations diverged with spruce/fir south of the ice sheets. Gene flow in the spruce budworm may also be affected by mountains in western North America, habitat isolation in West Virginia, regional adaptations, factors related to dispersal, and proximity of other species in the spruce budworm species complex. The central and eastern geographic regions contain individuals that assign to Eastern and Central subpopulations, respectively, indicating that these barriers are not complete. Our discovery of previously undetected geographic and genomic structure in the spruce budworm suggests that further population modelling of this ecologically important insect should consider regional differentiation, potentially co‐adapted blocks of genes, and gene flow between subpopulations.

Impact of dogs with deltamethrin-impregnated collars on prevalence of visceral leishmaniasis.

Leishmaniasis is a vector borne zoonosis which is classified as a neglected tropical disease. Among the three most common forms of the disease, Visceral Leishmaniasis (VL) is the most threatening to human health, causing 20,000 to 30,000 deaths worldwide each year. Areas where VL is mostly endemic have unprotected dogs in community and houses. The "presence of dogs usually increases VL risk for humans since dogs are the principal reservoir host for the parasite of the disease. Based on this fact, most earlier studies consider culling dogs as a control measure for the spread of VL. A more recent control measure has been the use of deltamethrin-impregnated dog collars (s) to protect both humans and dogs by putting s on dogs neck. The presence of dogs helps to grow the sandfly population faster by offering a more suitable blood-meal source. On the other hand, the presence of s on dogs helps to reduce sandfly population by the lethality of deltamethrin insecticide. This study brings an ecological perspective to this public health concern, aiming to understand the impact of an additional host (here, protected dogs) on disease risk to a primary host (here, humans). To answer this question, we compare two different settings: a community without dogs, and a community with dogs protected with . Our analysis shows the presence of protected dogs can reduce VL infection risk in humans. However, this disease risk reduction depends on dogs’ tolerance for sandfly bites.

Microhabitat determines uneven distribution of Amblyomma parvum but not of Amblyomma sculptum ticks within forest patches in the Brazilian Pantanal.

Environmental distribution of the two most abundant ticks in forest areas in the Brazilian Pantanal was evaluated by CO2 traps methodology in the wet season (peak of adult ticks) of 2012 and 2013. Adults of Amblyomma parvum were concentrated inside agglomerates of Bromelia balansae, in the border of forest patches. Adults of Amblyomma sculptum occurred in similar numbers both in bromeliad clumps and in bromeliad-free areas. Differential distribution of ticks in this habitat could be associated to the frequent use of bromeliad clumps by wild animals (potential hosts) and to the microclimate conditions inside this vegetation in the Pantanal. It is important to verify whether larvae and nymphs of A. parvum have a similar pattern of distribution in the same areas, during the dry season. These stages are more susceptible to desiccation and their principal hosts, non-volant small mammals, also use these bromeliad areas.

ROSS RIVER VIRUS IS A MOSQUITO-TRANSMITTED ALPHAVIRUS: IS IT THREATENED TO ARAB COUNTRIES INCLUDING EGYPT?

Ross River virus (RRV) is mosquito-borne arboviral infection that causes fever, polyarthritis, and rash. First described in northern Australia and then, widely throughout Australia and many western South Pacific islands. It is common in the tropical coastal regions of northern Australia. RRV can be transmitted by, Aedes aegypti, Ae. camptorhynchus, Ae. vigilax, and Culex annulirostris. Kangaroos, wallabies and horses are principal vertebrate hosts. Symptoms frequently occur together but may occur in single. Arthritis in wrists, knees, ankles, and finger joints is common and frequently symmetric. Rash is usually maculopapular involving limbs and trunk. Arthralgia may persist for up to 3 months. Fatigue is the commonest symptom. Diagnosis is by hemagglutination inhibition (HI) antibody and ELISA. A fourfold rise in HI titer is diagnostic; ≥1:1280 levels is recent infection. RRV-specific IgM persists for months after acute infection. Treatment is supportive care, analgesics, and non-steroidal anti-inflammatory drugs. Feasible preventive measure is avoidance of mosquito bites. Helpful interventions include use of window and door screens, mosquito repellants, and light colored clothing. Over the long-term, drainage of mosquito breeding areas in endemic areas may be helpful to control infection.

Global invasion genetics of two parasitic copepods infecting marine bivalves

Invasive species, and especially invasive parasites, represent excellent models to study ecological and evolutionary mechanisms in the wild. To understand these processes, it is crucial to obtain more knowledge on the native range, invasion routes and invasion history of invasive parasites. We investigated the consecutive invasions of two parasitic copepods (Mytilicola intestinalis and Mytilicolaorientalis) by combining an extensive literature survey covering the reported putative native regions and the present-day invaded regions with a global phylogeography of both species. The population genetic analyses based on partial COI sequences revealed significant population differentiation for M. orientalis within the native region in Japan, while introduced populations in North America and Europe could not be distinguished from the native ones. Thus, M. orientalis’ invasion history resembles the genetic structure and recent spread of its principal host, the Pacific oyster, Crassostrea gigas, while M. intestinalis lacks population genetic structure and has an overall low genetic diversity. Therefore, the native origin of M. intestinalis remains unclear. With this study, we demonstrate that even highly related and biologically similar invasive species can differ in their invasion genetics. From this, we conclude that extrapolating invasion genetics dynamics from related invasive taxa may not always be possible.

Differential phenotype of immune cells in blood and milk following pegylated granulocyte colony-stimulating factor therapy during a chronic Staphylococcus aureus infection in lactating Holsteins

Neutrophils are principal host innate immune cell responders to mastitis infections. Thus, therapies have been developed that target neutrophil expansion. This includes the neutrophil-stimulating cytokine granulocyte colony-stimulating factor (gCSF). Pegylated gCSF (PEG-gCSF; Imrestor, Elanco Animal Health, Greenfield, IN) has been shown to reduce the natural incidence of mastitis in periparturient cows in commercial settings and reduce severity of disease against experimental mastitis challenge. Pegylated gCSF stimulates neutrophil expansion but also induces changes in monocyte and lymphocyte circulating numbers, surface protein expression changes, or both. We hypothesized that PEG-gCSF modulates surface expression of monocytes and neutrophils and facilitates their migration to the mammary gland. We challenged 8 mid-lactation Holsteins with approximately 150 cfu of Staphylococcus aureus (Newbould 305) in a single quarter via intramammary infusion. All animals developed chronic infections as assessed by bacteria counts and somatic cell counts (SCC). Ten to 16 wk postchallenge, 4 of the animals were treated with 2 subcutaneous injections of PEG-gCSF 7 d apart. Complete blood counts, SCC, bacterial counts, milk yield, feed intake, neutrophils extracellular trap analysis, and flow cytometric analyses of milk and blood samples were performed at indicated time points for 14 d after the first PEG-gCSF injection. The PEG-gCSF-treated cows had significantly increased numbers of blood neutrophils and lymphocytes compared with control cows. Flow cytometric analyses revealed increased surface expression of myeloperoxidase (MPO) on neutrophils and macrophages in milk but not in blood of treated cows. Neutrophils isolated from blood of PEG-gCSF-treated cows had decreased surface expression of CD62L (L-selectin) in blood, consistent with cell activation. Surprisingly, CD62L cell surface expression was increased on neutrophils and macrophages sourced from milk from treated animals compared with cells isolated from controls. The PEG-gCSF-treated cows did not clear the S. aureus infection, nor did they significantly differ in SCC from controls. These findings provide evidence that PEG-gCSF therapy modifies cell surface expression of neutrophils and monocytes. However, although surface MPO+ cells accumulate in the mammary gland, the lack of bacterial control from these milk-derived cells suggests an incomplete role for PEG-gCSF treatment against chronic S. aureus infection and possibly chronic mammary infections in general.

Susceptibility of Coulter pine (Pinus coulteri) to western dwarf mistletoe (Arceuthobium campylopodum) in southern California

AbstractThe susceptibility of Coulter pine (Pinus coulteri) to western dwarf mistletoe (Arceuthobium campylopodum) was evaluated in southern California. Eight stands infested with western dwarf mistletoe and dominated by Coulter and Jeffrey pines (Pinus jeffreyi) were sampled. Infection of Coulter pine was evaluated using circular plots established around large, severely infected Jeffrey pines and with rectangular transects. A total of 25 plots and 10 transects were sampled. In each plot and transect, live trees > 5 cm in diameter at breast height (1.4 m above the ground) were assigned a dwarf mistletoe rating (6‐class system). Nearly 600 Jeffrey pines and more than 400 Coulter pines were evaluated. Infection of Jeffrey and Coulter pines in the plots and transects averaged 96% and 97%, respectively. These data indicate that Coulter pine should be classified as a principal host of WDM and not as a secondary host as previously reported.

First report of Echinococcus multilocularis in cats in Poland: a monitoring study in cats and dogs from a rural area and animal shelter in a highly endemic region

BackgroundAlveolar echinococcosis is a dangerous zoonotic disease caused by larval forms of Echinococcus multilocularis. In its life-cycle, the principal definitive host is the red fox; however, domesticated carnivorous animals (dogs and cats) can also act as definitive hosts. Until now, there were no data concerning this infection in cats in Poland. The aim of this study was to estimate the prevalence of E. multilocularis in cats and dogs originating from rural areas and animal shelters in a region characterised by a high prevalence of E. multilocularis in red foxes.MethodsSamples of faeces were collected from 67 cats and 268 dogs from a rural area (villages and animal shelters) of a highly endemic region in southeastern Poland. Samples were examined using nested PCR (E. multilocularis), multiplex PCR (E. multilocularis, Taenia spp.) and PCR [E. granulosus (s.l.)]. Additionally, faeces were examined microscopically (flotation). Moreover, intestines from 110 red foxes shot in the investigated area were examined (sedimentation and counting technique).ResultsPositive PCR results for E. multilocularis were obtained in 4 cats (6.0%) and 4 dogs (1.5%). There were no significant differences between groups of animals (from a shelter and with an owner) concerning the prevalence of E. multilocularis in both cats and dogs. Taenia spp. were found in 10 cats (14.9%) (Taenia taeniaeformis and T. hydatigena) and 26 dogs (9.7%) (T. hydatigena, T. serialis, T. taeniaeformis, T. crassiceps, T. pisiformis and T. ovis) and Mesocestoides litteratus was found in 4 cats (6.0%) and 3 dogs (1.1%). All samples were negative for E. granulosus by PCR. Taking into consideration PCR and flotation results, 29 cats (43.3%) and 73 dogs (27.2%) were infected with helminths (26.9 and 11.9%, respectively, were infected with tapeworms). The highly endemic status of the investigated area was confirmed by examination of red foxes: 48.2% of examined red foxes were infected with E. multilocularis.ConclusionsTo the best of our knowledge, this study reports the presence of E. multilocularis in cats for the first time in Poland and confirms the role of dogs in this infection in highly endemic areas.

First investigations on serum resistance and sensitivity of Borrelia turcica

Borrelia turcica is a reptile-associated Borrelia species that is vectored by the hard tick Hyalomma aegyptium. Tortoises of the genus Testudo represent the principal host of adult H. aegyptium, while immature stages are less host-specific and can be found on various vertebrates and even on humans. Borrelia turcica isolates were already successfully obtained from exotic tortoises suggesting that they are putative hosts. To the best of our knowledge, no further investigations on additional host association of B. turcica were conducted. Since many but not all adult Hyalomma ticks collected from tortoises are infected, questions arise about the direction of transmission between tick and tortoises for this Borrelia species. In addition, there is no information on the potential pathogenicity of B. turcica for humans. For other Borrelia species it has been shown that resistance or sensitivity to complement-active serum can be indicative of host species association(s). In this study, we explored for the first time the in vitro survival of B. turcica isolates from Turkey (IST7) and Greece (171601G) in the presence of 50% complement-active serum of different species (tortoise, turtle, human and bird). Both isolates showed resistance to tortoise serum, partial resistance to turtle serum but did not survive human and bird serum. These data suggest that indeed tortoises are reservoir host species for B. turcica while birds or humans are not. By implication these data suggest that B. turcica is not human pathogenic. Whether or not other reptile species, such as lizards, are also potential hosts, requires further investigation. However, as the life cycle of Borrelia is closely linked to that of their hosts and vectors, in vitro studies can only give clues about the actual in vivo behavior.

Phylogeny and taxonomy of Podosphaera cerasi, sp. nov., and Podosphaera prunicola sensu lato

ABSTRACTPowdery mildew of Prunus spp. is a significant disease in most cherry growing regions of Washington, USA. Powdery mildews on Prunus virginiana and Pr. avium were previously assigned to Podosphaera clandestina s. lat. (= Po. oxyacanthae) or Po. prunicola. In this report, we confirm the presence of two distinct Podosphaera species on these hosts. Phylogenetic analyses of nuc rDNA sequences from the internal transcribed spacer region (ITS1-5.8S-ITS2 = ITS) and 28S subunit confirmed the presence of two distinct species. A morphological comparison with type material of Po. prunicola and additional collections demonstrated that the powdery mildew on Pr. virginiana (including var. demissa and var. melanocarpa) is in fact Po. prunicola. The powdery mildew on Pr. avium is genetically, morphologically, and biologically distinct from Po. prunicola and is described here as the new species Po. cerasi. Cross-inoculation experiments confirmed that these two species are host specific. Podosphaera prunicola was unable to colonize Pr. avium, whereas Po. cerasi was unable to colonize Pr. virginiana. Morphological reexamination of numerous specimens identified as Po. prunicola on a broad range of Prunus species suggests that Po. prunicola is probably confined to species in Prunus subgen.Padus (= Prunus subgen. Cerasus sect. Laurocerasus, including sect. Padus), with Pr. virginiana as the principal host. Podosphaera cerasi occurs on hosts in Prunus subgen. Cerasus, and our work confirms a newly described species of powdery mildew on Pr. avium. This work also includes the first documented and genetically proven European record of Po. prunicola on Pr. serotina and its widespread occurrence in the United States.

Gualcamayo mining District, Argentina: An example of Carlin-like Au deposits

In the mid-1990′s Minas Argentina S.A. (MASA), subsidiary of Viceroy Exploration, began a reevaulation of the Gualcamayo district that included a drilling program. Low-grade gold was intercepted in breccias and in the San Juan Formation limestones. MASA estimated an inferred resource of 37.7 million tonnes @1.16 g/t gold in 2000, and Mineral Resources Development, Inc (MRDI) estimated resources were 37.2 million tonnes grading 1.13 g/t gold. The mineralized zones were superimposed on skarn, marble, breccias, and veins that appear related to a dacitic intrusive complex. Viceroy was subsequently purchased by Yamana Gold in 2003 who continued to explore the project area. Their 2006 National Instrument (NI) 43–101 report for the QDD portion of the Gualcamayo system estimates a measured and indicated resource of 74 million tones (Mt) averaging 0.88 g/t Au (cut-off of 0.3 g/t Au) with an additional 13.9 Mt grading 1.17 g/t Au inferred, yielding 2.6 million ounces of Au. Annual production of gold by Yamana Gold has ranged from 180,412 (2014) to 180,674 (2015) to 154,052 (2017) ounces of gold.This study was initiated to determine the origin of the gold deposits. Field and laboratory studies were conducted by the senior author as part of a doctoral research program comparing ores from Gualcamayo with those of the Great Basin, Nevada, including polished and thin section studies of ore and gangue minerals, followed by fluid inclusion, SEM, stable isotopic, and 40Ar/39Ar analyses to support the interpretations on ore genesis. The area under study corresponds to the Quebrada Del Diablo (QDD) target, which is located in the eastern part of the property.The disseminated gold mineralization in Gualcamayo is localized mainly within collapse breccias with minor values in decarbonatized limestone; all ore intervals are closely associated with elevated arsenic intervals. The San Juan Formation, principal ore host, with 50 m of dolomitic öoid packstone represents the stratigraphic unit that reacted with hydrothermal fluids. Intensely decarbonatized zones have collapsed, forming extensive zones of breccia. Hydrothermal fluid percolated through E-, W- and ENE-trending fault zones and along some bedding planes. The gold grades are maximized where those faults cut an earlier-formed NNW-trending antiform.Alteration of wallrocks in Gualcamayo (decarbonatization, carbon enrichment, local silicification and argillization) associated with disseminated gold includes many of the assemblages associated with Carlin-type (CTD) and distal-disseminated gold (DDD) deposits (Theodore et al., 2002). Additionally, the associated realgar, orpiment, cinnabar, pyrite, arsenian pyrite, marcasite, and minor base metal sulfides are common to CTD and DDD deposits.The Gualcamayo Igneous Complex evolved from an early tholeiitic to calc-alkaline series of magmas. The first stage of igneous activity occurred near 13 ± 2 Ma, and is represented by the Filon Capa Las Vacas dacite. At 8.99 ± 0.01 Ma the Varela Dacite Porphyry was emplaced. The last episode of magmatism corresponds to intrusion of El Rodado Dacite Porphyry at 5.6 ± 0.2 Ma. Field and petrographic relationships observed, together with the δ34S 0 permil values from disseminated sulfide minerals and skarn, suggest that gold mineralization stages were related to the emplacement of the Varela Dacite Porphyry. The inferred age for the disseminated-gold mineralization is <8.99 ± 0.01 Ma.The stable isotope values obtained for the host San Juan Formation limestone (δ18O values: 21.7 to 24‰ and δ13C values: −1.9 to 1.7‰), dolostone (δ18O values: 20.7–22.2‰ and δ13C values: −0.1 to 1.5‰), marbles and breccias at Gualcamayo are interpreted to have been developed as a result of exchange with hydrothermal fluids. The more altered and mineralized rocks exhibit a greater decrease in δ18O values. Some samples show an increase in their δ13C due to the presence of organic carbon in the system.Many characteristics common to Carlin-type (CTD) and Distal-disseminated (DDD) deposits are found in the Gualcamayo disseminated gold deposits. The similarities include the carbonate host rock, the disseminated minerals and textures, sulfide and gangue paragenesis, pyrite with arsenian pyrite overgrowths and associated gold, the alteration types, and comparable isotopic ratios. These similarities allow classifying the Gualcamayo deposits as Carlin-like deposits. Based on the relationship between the mineralization and the igneous activity in the area, the deposit could be interpreted as an intrusion-centered mineral deposit (Sillitoe and Bonham, 1990), characterized by a porphyry complex in the center, which grades outward through Fe-(Cu) skarn with minor Mo, Au, Ag, Bi and W to Pb-Zn-Ag vein, and to the disseminated carbonate- and breccia-hosted Au deposits similar to the McCoy-Cove system along the Battle Mountain-Eureka trend of Nevada.

Distribution records of three species of Leucochloridium (Trematoda: Leucochloridiidae) in Japan, with comments on their microtaxonomy and ecology

Insectivorous birds serve as definitive hosts for trematodes of the genus Leucochloridium. The parasites exclusively use amber snails of the family Succineidae as intermediate hosts. A pulsating and colorful display of the larval broodsac in the snail's eyestalk seems to be a caterpillar mimic for attracting birds. A colored design of the broodsac is very useful for parasite identification. In Japan, characteristic broodsacs from amber snails have been recorded from 1980's, but their taxonomic discrimination from Asian, European, and North American species has not been achieved. In this study, old scientific records, sighting information on broodsacs from the general public, and direct molecular evidence by DNA barcoding clearly showed that at least three species of Leucochloridium are distributed in Japan. A vertical-striped broodsac found from Succinea sp. in Okinawa, the subtropical island of Japan, were treated as Leucochloridium sp., but being almost identical to that of Leucochloridium passeri in neighboring Taiwan. The European species of Leucochloridium perturbatum and Leucochloridium paradoxum were frequently detected from Succinea lauta in Hokkaido, the northernmost island of Japan. The former species was common in inland areas of Hokkaido, whereas the latter species was frequently seen in the coastal areas. A possible explanation for the parasite distribution pattern is that principal definitive hosts (migratory or resident birds) differ in each parasite. The conspecificity of Leucochloridium variae in North America and L. perturbatum in Europe and the Far East is also discussed.