Veterinary Medicine Commons^™

Type X Strains Of Toxoplasma Gondii Are Virulent For Southern Sea Otters (Enhydra Lutris Nereis) And Present In Felids From Nearby Watersheds, Karen Shapiro, Elizabeth Vanwormer, Andrea Packham, Erin Dodd, Patricia A. Conrad, Melissa Miller

School of Veterinary and Biomedical Sciences: Faculty Publications

Why some Toxoplasma gondii-infected southern sea otters (Enhydra lutris nereis) develop fatal toxoplasmosis while others have incidental or mild chronic infections has long puzzled the scientific community. We assessed robust datasets on T. gondii molecular characterization in relation to detailed necropsy and histopathology results to evaluate whether parasite genotype influences pathological outcomes in sea otters that stranded along the central California coast. Genotypes isolated from sea otters were also compared with T. gondii strains circulating in felids from nearby coastal regions to assess land-to-sea parasite transmission. The predominant T. gondii genotypes isolated from 135 necropsied sea otters were atypical Type …

Environmental Transmission Of Toxoplasma Gondii: Oocysts In Water, Soil And Food, Karen Shapiro, Lillian Bahia-Oliveira, Brent Dixon, Aurélien Dumètre, Luz A. De Wit, Elizabeth Vanwormer, Isabelle Villena

School of Veterinary and Biomedical Sciences: Faculty Publications

Toxoplasma gondii is a zoonotic protozoan parasite that can cause morbidity and mortality in humans, domestic animals, and terrestrial and aquatic wildlife. The environmentally robust oocyst stage of T. gondii is fundamentally critical to the parasite's success, both in terms of its worldwide distribution as well as the extensive range of infected intermediate hosts. Despite the limited definitive host species (domestic and wild felids), infections have been reported on every continent, and in terrestrial as well as aquatic environments. The remarkable resistance of the oocyst wall enables dissemination of T. gondii through watersheds and ecosystems, and long-term persistence in diverse …

Transmission Potential Of Rickettsia Felis Through Cutaneous Inoculation Of Infectious Flea Feces, Kelsey Porter Legendre

LSU Master's Theses

Rickettsia felis, the causative agent of flea-borne spotted fever, is an emerging pathogen of the transitional group Rickettsiae and an important cause of febrile illness in Africa. Since the organism’s original discovery in the early 1990s, much research has been directed towards elucidating transmission mechanisms within the believed primary host and reservoir, the cat flea (Ctenocephalides felis). However, while a growing number of human cases are being reported throughout the world, a definitive transmission mechanism from arthropod host to vertebrate host resulting in clinical disease has not been found. Several possible mechanisms, including bite of infected arthropods …

Development Of Mouse Models For The Study Of Zika Virus Pathogenesis And Antibody Response, Anna Beatriz Kawiecki

LSU Master's Theses

After the emergence of Zika virus (ZIKV) in the Americas in 2015, ZIKV infection was associated for the first time since its discovery with severe symptoms in both adults and congenital cases, including neurological, ocular, and developmental manifestations. Previous ZIKV circulation in Africa and Southeast Asia has been characterized by mild symptoms and small-scale case-counts. It is unclear whether the unprecedented size and severity of the ZIKV outbreak in the Americas are the consequence of a change in the virus, different background flaviviral immunity in the population, or a reporting issue. In addition, ZIKV has been shown to be transmitted …

Rickettsia Felis, Transmission Mechanisms Of An Emerging Flea-Borne Rickettsiosis, Lisa Diane Brown

LSU Doctoral Dissertations

Rickettsia felis is an emerging insect-borne rickettsial pathogen and the causative agent of flea-borne spotted fever. First described as a human pathogen from the United States in 1991, R. felis is now identified throughout the world and considered a common cause of fever in Africa. The cosmopolitan distribution of this pathogen is credited to the equally widespread occurrence of cat fleas (Ctenocephalides felis), the primary vector and reservoir of R. felis. Additionally, R. felis has been identified in other hematophagous arthropods (including numerous species of fleas, ticks, mosquitoes, and mites). Most transmission cycles of pathogenic Rickettsia include transovarial and transstadial …

An Evaluation Of Contaminated Complete Feed As A Vehicle For Porcine Epidemic Diarrhea Virus Infection Of Naïve Pigs Following Consumption Via Natural Feeding Behavior: Proof Of Concept, Scott Dee, Travis Clement, Adam Schelkopf, Joel Nerem, David Knudsen, Jane Christopher-Hennings, Eric A. Nelson

Veterinary and Biomedical Sciences Faculty Publications

Background: Since its initial detection in May 2013, porcine epidemic diarrhea virus (PEDV) has spread rapidly throughout the US swine industry. Initially, contaminated feed was proposed as a risk factor for PEDV; however, data were not available to support this theory. Here we provide proof of concept of this risk by describing a novel means for recovering PEDV-contaminated complete feed material from commercial swine sites and conducting an in vivo experiment to prove its infectivity.

Results: For on-farm detection of PEDV RNA in feed, paint rollers were used to collect material from at-risk feed bins from 3 clinically affected breeding …

Arbovirus Phenotype Alters Transmission Potential, Rebecca C. Christofferson

LSU Doctoral Dissertations

Extrinsic and environmental factors are known to affect the transmission of arthropod-borne viruses (arboviruses), including variations in the arthropod vector populations. Differences among these factors have been associated with differential transmission and are sometimes used to control the spread of an arbovirus through a vertebrate population in an effort to prevent or disrupt an outbreak. However, diversity in intrinsic viral populations, such as genetic and phenotypic variability, is not often accounted for when considering alterations in transmission. Presented in this dissertation are four experimental studies that explore the contribution of viral intrinsic factors, especially phenotypic variability, to the transmission potential …