Diversity of Francisella Species in Environmental Samples from Martha’s Vineyard, Massachusetts

We determined whether Francisella spp. are present in water, sediment, and soil from an active tularemia natural focus on Martha’s Vineyard, Massachusetts, during a multiyear outbreak of pneumonic tularemia. Environmental samples were tested by polymerase chain reaction (PCR) targeting Francisella species 16S rRNA gene and succinate dehydrogenase A (sdhA) sequences; evidence of the agent of tularemia was sought by amplification of Francisella tularensis-specific sequences for the insertion element ISFTu2, 17-kDa protein gene tul4, and the 43-kDa outer membrane protein gene fopA. Evidence of F. tularensis subsp. tularensis, the causative agent of the human infections in this outbreak, was not detected from environmental samples despite its active transmission among ticks and animals in the sampling site. Francisella philomiragia was frequently detected from a brackish-water pond using Francisella species PCR targets, and subsequently F. philomiragia was isolated from an individual brackish-water sample. Distinct Francisella sp. sequences that are closely related to F. tularensis and Francisella novicida were detected from samples collected from the brackish-water pond. We conclude that diverse Francisella spp. are present in the environment where human cases of pneumonic tularemia occur

Infección por Theileria annae en un perro esplenectomizado

La babesiosis canina es una enfermedad infecciosa de distribución mundial debida a la proliferación en los hematíes del perro de unas babesias específicas transmitidas por garrapatas. Si bien ha sido tradicionalmente asumido que las únicas especies que causan enfermedad en la especie canina son Babesia canis y Babesia gibsoni, publicaciones recientes demuestran que una tercera especie (Theileria annae) también puede causar una enfermedad muy severa. Este trabajo presenta el segundo caso publicado de esta forma de Theileria annae en un perro de 14 años, de raza Basset Hound, esplenectomizado cinco meses antes, que se presentó en la clínica veterinaria con signos de hipertermia, hemoglobinuria, temblores y apatía. El estudio de laboratorio constató una acusada anemia hemolítica regenerativa y una intensa trombocitopenia como datos más característicos. En la extensión de sangre periférica se visualizaron múltiples merozoítos intra (22%) y extraeritrocitarios de pequeño tamaño (1-2 micras), forma anular y presentación única en la mayoría de hematíes. La prontitud del diagnóstico y del tratamiento específico con dipropionato de imidocarb hizo que el cuadro clínico evolucionase con rapidez hacia la curación, en contra de lo que es habitual en los animales esplenectomizados.

Nonrandom Distribution of Vector Ticks (Dermacentor variabilis) Infected by Francisella tularensis

The island of Martha's Vineyard, Massachusetts, is the site of a sustained outbreak of tularemia due to Francisella tularensis tularensis. Dog ticks, Dermacentor variabilis, appear to be critical in the perpetuation of the agent there. Tularemia has long been characterized as an agent of natural focality, stably persisting in characteristic sites of transmission, but this suggestion has never been rigorously tested. Accordingly, we sought to identify a natural focus of transmission of the agent of tularemia by mapping the distribution of PCR-positive ticks. From 2004 to 2007, questing D. variabilis were collected from 85 individual waypoints along a 1.5 km transect in a field site on Martha's Vineyard. The positions of PCR-positive ticks were then mapped using ArcGIS. Cluster analysis identified an area approximately 290 meters in diameter, 9 waypoints, that was significantly more likely to yield PCR-positive ticks (relative risk 3.3, P = 0.001) than the rest of the field site. Genotyping of F. tularensis using variable number tandem repeat (VNTR) analysis on PCR-positive ticks yielded 13 different haplotypes, the vast majority of which was one dominant haplotype. Positive ticks collected in the cluster were 3.4 times (relative risk = 3.4, P<0.0001) more likely to have an uncommon haplotype than those collected elsewhere from the transect. We conclude that we have identified a microfocus where the agent of tularemia stably perpetuates and that this area is where genetic diversity is generated

The Compressible Flow Past Various Plane Profiles Near Sonic Velocity

In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by.Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve. After exceeding a certain Mach number where local supersonic fields occur already, it was no longer possible, in spite of the substantially increased number of steps, to obtain a systematic solution because the calculation diverged. This result,was interpreted to mean that above this point of divergence the symmetrical type of flow ceases to exist and changes into the unsymmetrical type characterized by compressibility shocks

The Calculation of Compressible Flows with Local Regions of Supersonic Velocity

This report addresses a method for the approximate calculation of compressible flows about profiles with local regions of supersonic velocity. The flow around a slender profile is treated as an example