Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk, and little is known about its transmissibility to other species. An important factor controlling interspecies TSE susceptibility is prion protein (PrP) homology between the source and recipient species/genotypes. Furthermore, the ef®ciency with which the proteaseresistant PrP (PrP-res) of one species induces the in vitro conversion of the normal PrP (PrP-sen) of another species to the protease-resistant state correlates with the cross-species transmissibility of TSE agents. Here we show that the CWD-associated PrPres (PrP CWD ) of cervids readily induces the conversion of recombinant cervid PrP-sen molecules to the protease-resistant state in accordance with the known transmissibility of CWD between cervids. In contrast, PrP CWD -induced conversions of human and bovine PrP-sen were much less ef®cient, and conversion of ovine PrP-sen was intermediate. These results demonstrate a barrier at the molecular level that should limit the susceptibility of these non-cervid species to CWD. Keywords: cell-free conversion/chronic wasting disease (CWD)/prion protein (PrP)/scrapie/transmissible spongiform encephalopathy (TSE)

Chronic wasting disease (CWD) is an emerging transmissible spongiform encephalopathy (prion disease) of

Widespread deaths of American Crows (Corvus brachyrhynchos) were associated with the 1999 outbreak of West Nile (WN) virus in the New York City region. We compared six organs from 20 crow carcasses as targets for WN virus detection. Half the carcasses had at least one positive test result for WN virus infection. The brain was the most sensitive target organ; it was the only positive organ for three of the positive crows. The sensitivity of crow organs as targets for WN virus detection makes crow death useful for WN virus surveillance.

In total, 1,324 Culex pipiens pipiens L. female mosquitoes were collected at Ft. Hancock, Monmouth County, New Jersey, from January to March 2001-2003. Mosquitoes were held in an insectary at 27 degrees C and a photoperiod of 16:8 (L:D) h for 6 to 21 d after which they were tested in 34 pools. West Nile viral RNA was detected in one pool by a TaqMan reverse transcription-polymerase chain reaction assay; however, infectious virus could not be isolated using either Vero cell plaque assay or C6/36 mosquito cells. Twenty females dissected in January and March 2003 confirmed ovarian diapause status. We suggest that the mode of infection in this pool of overwintering females may have been due to vertical (transgenerational) transmission.

West Nile virus (WNV) was detected by Taqman reverse transcription-polymerase chain reaction in 4 of 85 (4.7%) blood-engorged (n = 2) and unengorged (n = 2) Icosta americana (Leach) hippoboscid flies that were collected from wild raptors submitted to a wildlife rehabilitation center in Mercer County, NJ, in 2003. This report represents an additional detection of WNV in a nonculicine arthropod in North America and the first documented detection of the virus in unengorged hippoboscid flies, further suggesting a possible role that this species may play in the transmission of WNV in North America.

In total, 1,324 Culex pipiens pipiens L. female mosquitoes were collected at Ft. Hancock, Monmouth County, New Jersey, from January to March 2001-2003. Mosquitoes were held in an insectary at 27 degrees C and a photoperiod of 16:8 (L:D) h for 6 to 21 d after which they were tested in 34 pools. West Nile viral RNA was detected in one pool by a TaqMan reverse transcription-polymerase chain reaction assay; however, infectious virus could not be isolated using either Vero cell plaque assay or C6/36 mosquito cells. Twenty females dissected in January and March 2003 confirmed ovarian diapause status. We suggest that the mode of infection in this pool of overwintering females may have been due to vertical (transgenerational) transmission.

Rift Valley fever virus (RVFV) causes disease outbreaks across Africa and the Arabian Peninsula, resulting in high morbidity and mortality among young domestic livestock, frequent abortions in pregnant animals, and potentially severe or fatal disease in humans. The possibility of RVFV spreading to the United States or other countries worldwide is of significant concern to animal and public health, livestock production, and trade. The mechanism for persistence of RVFV during inter-epidemic periods may be through mosquito transovarial transmission and/or by means of a wildlife reservoir. Field investigations in endemic areas and previous in vivo studies have demonstrated that RVFV can infect a wide range of animals, including indigenous wild ruminants of Africa. Yet no predominant wildlife reservoir has been identified, and gaps in our knowledge of RVFV permissive hosts still remain. In North America, domestic goats, sheep, and cattle are susceptible hosts for RVFV and several competent vectors exist. Wild ruminants such as deer might serve as a virus reservoir and given their abundance, wide distribution, and overlap with livestock farms and human populated areas could represent an important risk factor. The objective of this study was to assess a variety of cell lines derived from North American livestock and wildlife for susceptibility and permissiveness to RVFV. Results of this study suggest that RVFV could potentially replicate in native deer species such as white-tailed deer, and possibly a wide range of non-ruminant animals. This work serves to guide and support future animal model studies and risk model assessment regarding this high-consequence zoonotic pathogen.

We have demonstrated the feasibility of linking newborn blood spots, population-based cancer incidence data and birth certificate data. Incident cases of acute lymphocytic leukaemia and population-based controls were ascertained. We retrieved dried blood spot specimens, isolated and amplified DNA, and assayed the cancer susceptibility genes GSTT1 and GSTM1. The double null genotype was over-represented in the cases, consistent with previous reports based on other epidemiological methods. The design avoids issues of participation bias by cases and controls and can be used to investigate interactions of susceptibility genes and xenobiotics in semi-ecological studies. It can be useful for generating or testing hypotheses on associations of other paediatric illness and environmental contaminants.