Emerging infectious disease leads to rapid population declines of common British birds.

Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period.

The development of [(124)I]iodinated-VG76e: a novel tracer for imaging vascular endothelial growth factor in vivo using positron emission tomography.

The development of anticancer therapies that target the angiogenic process is an area of major growth in oncology. A method of noninvasively measuring tumor vascular endothelial growth factor (VEGF) in vivo could provide important efficacy information for VEGF-dependent antiangiogenic agents and the role of VEGF in cancer biology. We have developed a novel radiotracer for use with positron emission tomography (PET) that enables noninvasive imaging of VEGF. This radiotracer comprises an IgG1 monoclonal antibody, known as VG76e, that binds to human VEGF, labeled with a positron-emitting radionuclide, iodine-124 ([(124)I]-SHPP-VG76e). Three radiolabeling strategies were evaluated to synthesize the radiotracer with optimal radiochemical yield, purity, and immunoreactivity. To evaluate the pharmacokinetics and VEGF-specific localization of [(124)I]-SHPP-VG76e, two subclones of the HT1080 human fibrosarcoma selected on the basis of differing VEGF production (26.6 and 1/3C, the former producing 2-4-fold more in vitro) were established in culture and grown as solid tumor xenografts in immune-deficient mice. A single i.v. injection of the radiotracer into tumor-bearing mice revealed a time dependent and specific localization of [(125)I]-SHPP-VG76e to the tumor tissue. Three validation studies established the VEGF specificity and potential for use of [(124)I]-SHPP-VG76e in vivo: (a) uptake of [(125)I]-SHPP-VG76e was 1.8-fold higher in HT1080-26.6 compared with HT1080-1/3C tumors (P < 0.05); (b) uptake of [(125)I]-SHPP-VG76e in HT1080-26.6 tumors was specifically blocked by prior administration of excess unlabeled VG76e (P < 0.05); and (c) tumor uptake of the IgG1, [(125)I]-SHPP-CIP5, which has a similar molecular weight as [(125)I]-SHPP-VG76e but does not recognize VEGF, was the same for both HT1080-26.6 and HT1080-1/3C (P > 0.05). Other than tumor localization, [(125)I]-SHPP-VG76e was present in urine and blood and to a lesser extent in heart, lungs, liver, kidney, and spleen. Whole-animal PET imaging studies revealed a high tumor-to-background contrast and also revealed [(124)I]-SHPP-VG76e distributions in the major organs. These studies support further development of [(124)I]-SHPP-VG76e as a radiotracer for measuring tumor levels of VEGF in humans.