Proteins encoded in the 5' region of the pestivirus genome--considerations concerning taxonomy.

The first protein encoded within the pestivirus open reading frame is a nonstructural protein which removes itself from the polyprotein by autoproteolytic cleavage. The following nucleocapsid protein ends just before a putative signal sequence preceding three glycosylated proteins. All three glycoproteins are part of the viral envelope and exist in the form of disulfide-linked dimers. Pestiviruses have recently been reclassified as members of the family Flaviviridae which now comprises three genera, namely flavivirus, hepatitis C virus group and pestivirus. All members of the family have certain characteristics in common like the overall genome organization and the strategy of gene expression. Major differences exist, however, between the genera; the most obvious ones concern proteins encoded in the 5' region of the respective genomes.     

The genetic basis for cytopathogenicity of pestiviruses

Two biotypes of pestiviruses, cytopathogenic (cp) and noncp viruses, can be distinguished by their effects on tissue culture cells. Identification of cp bovine viral diarrhea virus (BVDV) has been frequently reported since antigenically closely related noncp and cp BVDV can be isolated from cattle with fatal mucosal disease (MD) and are called a virus pair. In contrast to the BVDV system, only few cp border disease virus (BDV) and cp classical swine fever virus (CSFV) strains have been described. Serological analyses and sequence comparison studies showed that cp pestiviruses arise from noncp viruses by mutation. Elaborate studies during the last 10 years revealed that in most cases RNA recombination is responsible for the generation of the cp viruses. Recent results showed a second way for the development of a cp pestivirus which is based on the introduction of a set of point mutations within the NS2 gene.     

Alterations in coagulation and hemograms of horses given endotoxins for 24 hours via hepatic portal infusions

This experiment was designed to establish a model for the study of gastrointestinal disturbances as a result of prolonged endotoxin uptake in the horse. The hepatic portal vein of 7 horses was catheterized (through flank incisions) to give chronic hepatic portal infusions of lipopolysaccharide (LPS, endotoxin). Lipopolysaccharide was infused at a rate of 1 microgram/kg of body weight/hr for 24 hours. Two of the horses were infused with saline solution for 12 hours before LPS infusions were given. Lipopolysaccharide was shown to affect behavior and hematologic and coagulation values. The 1st hour was critical for the LPS-infused horses; yet by 4 hours, the horses had apparently become refractory to continued infusion of LPS. During the 1st hour, all horses collapsed without an accompanying hypotension. A decrease in polymorphonuclear leukocytes (neutrophils) was seen during this time and was accompanied by a shortening of the recalcification tests, 1-stage prothrombin time, and activated partial thromboplastin time. There was an increased concentration of circulating fibrinogen/fibrin degradatory products. All of the LPS-infused horses showed signs of hoof discomfort and either stood with the 4 feet together beneath the body or continually shifted their weight from one front foot to the other. Hoof temperature decreased approximately 3 degrees (C) during this time and remained decreased for the duration of the experiment.     

Experimental leprosy in three species of monkeys

Eleven mangabey monkeys inoculated with Mycobacterium leprae developed lepromatous-type leprosy. Nine of the mangabeys were inoculated with M. leprae isolated from a mangabey with naturally acquired lepromatous leprosy. Immune function was depressed in some of these animals after dissemination of the disease. Two mangabeys developed lepromatous leprosy after inoculation with human M. leprae passaged in an armadillo. Three rhesus and three African green monkeys inoculated with mangabey-derived M. leprae also developed lepromatous leprosy. Mangabeys may be the first reported nonhuman primate model for the study of leprosy. Rhesus and African green monkeys may also prove to be reproducibly susceptible to the disease.     

Choice and voice: creating a community of practice in KwaZulu-Natal,South Africa

The development and utility of genetically modified (GM) crops for smallholders around the world is controversial. Critical questions include what traits and crops are to be developed; how they can be adapted to smallholders’ ecological, social and economic contexts; which dissemination channels should be used to reach smallholders; and which policy environments will enable the greatest benefits for smallholders and the rural poor. A key question is how the voices of smallholders who have experience with or desire to use GM technologies enter the larger debate. Africa has the greatest number of smallholders and poor with the least exposure to GM crops. Because of the well-established use of GM crops in South Africa by commercial farmers, we formed a community of practice (CoP) involving smallholders, extension, researchers, non-profits and agribusiness in KwaZulu-Natal to examine the conditions under which GM crops are used by smallholders, how smallholders interact with GM technologies and what insights smallholders and other stakeholders can provide regarding these questions. One of the advantages of the CoP approach is that it brings stakeholders together in a non-hierarchical way that encourages new ways of thinking and new partnerships. Such interaction around a specific project can enhance the voice of smallholders in a variety of ways. In our project, smallholder participants have increased their knowledge and can make better decisions about GM technologies, which had been barriers for them. Notably, they have also improved their knowledge of maize production practices, accessed new practice networks, and met new researchers and resource providers. They are now being integrated into these networks in a way that should improve their livelihoods and make the wants and needs of smallholders better known. Such knowledge and experience has improved their voice in agriculture and rural development discussions.     

Fish: serologic evidence of infection with human pathogens

Specific antibodies to several bacteria pathogenic to humans were detected in the serums of white perch from surface waters adjacent to heavily populated areas on Chesapeake Bay. White perch from surface waters adjacent to sparsely populated areas were free of such antibodies. We suggest that fish may become actively infected with human pathogens by exposure to contaminated water and may constitute a hazard to public health.