Emergence of Zoonotic Canine Leishmaniasis in the United States: Isolation and Immunohistochemical Detection of Leishmania infantum from Foxhounds from Virginia.

ABSTRACT. Previously considered an exotic disease, canine leishmaniasis caused by Leishmania infantum has recently been detected within the foxhound population in the United States and parts of Canada. Leishmania infantum is the etiologic agent of visceral leishmaniasis in many areas of the world and dogs are considered a major reservoir host for human Leishmania infections. Human visceral leishmaniasis has recently emerged as an opportunistic infection among individuals co-infected with HIV/AIDS and in persons taking immunosuppressive drugs. We report the isolation of L. infantum from 3 naturally infected foxhounds from Virginia by culture of popliteal lymph node and bone marrow, and the development of an immunohistochemical test to detect the parasite in tissues.     

Regeneration patterns and persistence of the fog-dependent Fray Jorge forest in semiarid Chile during the past two centuries

The persistence of rainforest patches at Fray Jorge National Park (FJNP) in semiarid Chile (30°40′S), a region receiving approximately 147 mm of annual rainfall, has been a source of concern among forest managers. These forests are likely dependent on water inputs from oceanic fog and their persistence seems uncertain in the face of climate change. Here, we assessed tree radial growth and establishment during the last two centuries and their relation to trends in climate and canopy disturbance. Such evaluation is critical to understanding the dynamics of these semiarid ecosystems in response to climate change. We analyzed forest structure of six forest patches (0.2–22 ha) in FJNP based on sampling within 0.1 ha permanent plots. For the main canopy species, the endemic Aextoxicon punctatum (Aextoxicaceae), we used tree‐ring analysis to assess establishment periods, tree ages, growing trends and their relation to El Niño Southern Oscillation (ENSO), rainfall, and disturbance. The population dynamics of A. punctatum can be described by a continuous regeneration mode. Regeneration of A. punctatum was sensitive to different canopy structures. Growth release patterns suggest the absence of large scale human impact. Radial growth and establishment of A. punctatum were weakly correlated with rainfall and ENSO. If water limits forests patch persistence, patches are likely dependent on the combination of fog and rain water inputs. Forest patches have regenerated continuously for at least 250 years, despite large fluctuations in rainfall driven by ENSO and a regional decline in rainfall during the last century. Because of the positive influence on fog interception, forest structure should be preserved under any future climate scenario. Future research in FJNP should prioritize quantifying the long‐term trends of fog water deposition on forests patches. Fog modeling is crucial for understanding the interplay among physical drivers of water inputs under climate change.     

Patterns in the life histories and feeding strategies of British macrolepidoptera

Temperate Lepidoptera typically have life cycles of a year or less. The time available to feed and attain a suitable state for reproduction might thus constrain potential life-history patterns, and species characteristics such as adult size, overwintering stage, first month of larval feeding and feeding specificity may only occur in particular combinations. Several studies have documented correlates of feeding ecology which suggest this is indeed the case. We use data for more than 900 British macrolepidoptera to establish relationships among several ecological and life-history variables to determine whether only particular combinations can occur. Few patterns of feeding characteristics predicted in the literature are observed. Distinct, consistent life-history syndromes cannot be defined; almost any combination of the life-history characteristics we looked at can occur. So long as it is possible to fit in with timing constraints at certain critical times of year, there seems to be a great deal of flexibility in how the rest of the time can be filled. However, several broad and potentially interesting patterns still emerge. Polyphagous species are larger than specialists; the month in which species start to feed inlinked to both their overwintering stage and the growth form of the plant they feed upon; and there are no species overwintering in the egg stage and having two broods per year.     

Life histories of Clethrionomys and Microtus (Microtinae)

Although there have been numerous life-history reviews of mammals at high taxonomic levels (e.g. among families within orders), there are far fewer studies at lower taxonomic levels (e.g. among species within genera). Data on adult weights, litter size, gestation length, neonate weight, age and weight at weaning, growth rate to weaning, maximum life span, and length of the breeding season were compiled from the literature on five species of Clethrionomys and 33 species of Microtus. Variability in litter size and male body weights was not significantly different when compared between cyclic and non-cyclic populations. Coefficients of variation were also calculated for the three species with the most data (C. gapperi, C. glareolus and M. pennsylvanicus ). These values showed that the amount of intraspecific variation differed among traits as well as among species. Gestation length was the most invariable of all traits and variation in adult weights, neonate weight, gestation length, and litter size had similar values to those reported for Peromyscus maniculatus. Five and eight traits differed among Clethrionomys and Microtus species, respectively. Differences in litter size, adult weights and length of the breeding season were common to both genera. Male weight, gestation length and neonate weight as well as length of the breeding season were different between genera. Very few traits covaried within C. gapperi, C. glareolus or M. pennsylvanicus. Similarly, few traits covaried among all Clethrionomys populations. However, among all Microtus populations and Microtus species, 11 and 12 correlations were significant. Many of the patterns found in Microtus involved positive relationships between female weight and some other trait. These patterns have also been found by broader surveys at higher taxonomic levels. Large species of Microtus had larger offspring, a greater litter size and occurred in short-season environments relative to small species of this genus.     

INSECTICIDES FOR PREVENTING BARNACLE SETTLEMENT

During the summer of 1950 experiments were made to test the use of insecticides for preventing the fouling of oyster spat collectors by the barnacle Elminius modestus.
The insecticides used were DDT, BHC (benzene hexachloride-γ-isomer) and dieldrin (hexachloro-epoxy-octahydro-dimethano-naphthalene), made up as 5% solutions and tested on egg-box collectors and quarry tiles. The tiles were used for frequent observations on settlement.
When the solutions were sprayed on to the surfaces, in sufficient quantity to give a covering of 200 mg./ft.² of active insecticide, none of them interfered with either barnacle or oyster settlement.
When the test surfaces were dipped in the solutions, DDT and BHC prevented barnacle settlement almost completely, while dieldrin reduced it by approximately 50%. Settlement of Ostrea edulis was also reduced on the treated surfaces.
Urea-formaldehyde resins made up as varnishes, to which DDT or BHC had been added, were also tested. A varnish incorporating 20% by weight of DDT provided an effective anti-fouling compound which lasted at least 3 months and completely prevented barnacle settlement.
The possibility of insecticides dissolving into the water and inhibiting barnacle growth on adjacent surfaces is discussed.     

Narcissus late season yellows potyvirus: symptoms, properties and serological detection

Narcissus late season yellows virus (NLSYV) was obtained, apparently unmixed with other viruses, in selected naturally infected narcissus plants. The virus was not transmitted by manual inoculation to any of the 12 herbaceous species tested but was transmitted by Myzus persicae to virus-tested narcissus plants, which then developed symptoms characteristic of late season yellows. Typically, symptoms develop late in the growing season but their expression is unreliable. NLSYV particles, which measured c. 750 ± 12 nm, were purified from fresh leaf extracts of narcissus in 0·3 m sodium citrate containing 10 mm sodium EDTA and 10 mm sodium DIECA by differential centrifugation followed by clarification with diethyl ether, gel filtration and isopycnic banding in caesium sulphate. Using antibodies from antisera prepared to virus particles, NLSYV was detected by ELISA in 14 of the 18 cultivars examined and nine seemed totally infected. Detection of the virus by immunosorbent electron microscopy was as sensitive as by ELISA but neither test detected all infections. The virus was detected by ELISA only in samples collected after flowering and capsid antigen concentration was greatest in the distal region of leaves. The reliability of detection depended on the cultivar. Immuno-electron microscopy tests confirmed the occurrence of a distinct potyvirus, presumably narcissus degeneration, in narcissus cv. Grand Soleil d'Or, failed to detect any virus other than NLSYV in narcissus plants affected by white streak disease, and showed that NLSYV is related to three of five other potyviruses tested.     

Relationships of the Galapagos flora

Joseph Dalton Hooker's pioneer 1847 paper on Galapagos plants and their relationships is a classic in the field of phytogeography. It was the first study of its kind to be published, comparing the islands' flora with island and continental floras elsewhere, hypothesizing on the dispersal mechanisms of the plants, and pointing out anomalies in the inter-island distributions of the native species. These are still three of the primary concerns of contemporary phytogeographers, and the present paper contrasts Hooker's findings with those of today. Despite the accumulation of a large amount of data since his time, many of Hooker's conclusions regarding Galapagos phytogeography remain valid.