Sarcocystis neurona infections in raccoons (Procyon lotor): evidence for natural infection with sarcocysts, transmission of infection to opossums (Didelphis virginiana), and experimental induction of neurologic disease in raccoons

Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses in the Americas and Sarcocystis neurona is the most common etiologic agent. The distribution of S. neurona infections follows the geographical distributions of its definitive hosts, opossums (Didelphis virginiana, Didelphis albiventris). Recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of S. neurona. In the present report, raccoons (Procyon lotor) were identified as a natural intermediate host of S. neurona. Two laboratory-raised opossums were found to shed S. neurona-like sporocysts after ingesting tongues of naturally-infected raccoons. Interferon-gamma gene knockout (KO) mice fed raccoon-opossum-derived sporocysts developed neurologic signs. S. neurona was identified immunohistochemically in tissues of KO mice fed sporocysts and the parasite was isolated in cell cultures inoculated with infected KO mouse tissues. The DNA obtained from the tongue of a naturally-infected raccoon, brains of KO mice that had neurological signs, and from the organisms recovered in cell cultures inoculated with brains of neurologic KO mice, corresponded to that of S. neurona. Two raccoons fed mature S. neurona sarcocysts did not shed sporocysts in their feces, indicating raccoons are not likely to be its definitive host. Two raccoons fed sporocysts from opossum feces developed clinical illness and S. neurona-associated encephalomyelitis was found in raccoons killed 14 and 22 days after feeding sporocysts; schizonts and merozoites were seen in encephalitic lesions.     

Canine babesiosis.

Canine babesiosis is a tickborne, protozoal, hemoparasitic disease that can cause varying degrees of hemolytic anemia, splenomegaly, thrombocytopenia, and fever. Babesia organisms frequently are classified as large or small. Large Babesia infections are attributed to one of three subspecies of Babesia canis. All small Babesia infections previously were attributed to B gibsoni, but molecular analysis and DNA sequencing have revealed that there are at least three small piroplasms infecting dogs. Correctly identifying the infectious agent is important for treatment planning and prognosis.     

Canadian Prairie Rangeland and Seeded Forage Classification Using Multiseason Landsat 8 and Summer RADARSAT-2

Rangeland and seeded forage in Canada’s Prairie provinces represent productive landscapes that provide multiple ecosystem services. Past efforts to map these resources at regional scales have not achieved consistently high accuracies as they are spatially variable in both ecology and management. In particular, Agriculture and Agri-food Canada needs to distinguish these land use classes from each other and from cropland in its annual national agricultural land cover inventory. Given the potential to distinguish these classes based on seasonal phenological differences, this study used multi-season Landsat 8 top-of-atmosphere reflectance data and derived vegetation and phenological indices, as well as mid-summer RADARSAT-2 data in random forest classification of two ecoregions in Alberta and Manitoba. Classification accuracy was compared for single and multi-date Landsat 8 variables, the vegetation index and phenological variable groups, RADARSAT-2 VV and VH backscatter intensity, and combined datasets. Variable importance analysis showed that spring Landsat 8 reflectance generally contributed most to class discrimination, but accuracy improved with the addition of Landsat 8 data from the other seasons. Vegetation indices and phenological variables produced similar accuracies and were deemed to not warrant the additional processing effort to derive them. RADARSAT-2 VH backscatter was the most important variable for the Manitoba study area, which is wetter with more vegetation structure variability than the Alberta study area. Backscatter intensity significantly increased overall accuracy when it was combined with one or two-season Landsat 8 data. The best overall accuracy was achieved using the three seasons of Landsat 8 and mid-summer RADARSAT-2 data, but it was not significantly better than that for two season Landsat 8 + RADARSAT-2. The methods presented in this paper provide a process for accurate and efficient classification of seeded forage, rangeland and cropland that can be applied over large areas in operational agricultural land cover inventory.     

Nucleus accumbens long-term depression and the expression of behavioral sensitization

Drug-dependent neural plasticity related to drug addiction and schizophrenia can be modeled in animals as behavioral sensitization, which is induced by repeated noncontingent or self-administration of many drugs of abuse. Molecular mechanisms that are critical for behavioral sensitization have yet to be specified. Long-term depression (LTD) of alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor (AMPAR)-mediated synaptic transmission in the brain has been proposed as a cellular substrate for learning and memory. The expression of LTD in the nucleus accumbens (NAc) required clathrin-dependent endocytosis of postsynaptic AMPARs. NAc LTD was blocked by a dynamin-derived peptide that inhibited clathrin-mediated endocytosis or by a GluR2-derived peptide that blocked regulated AMPAR endocytosis. Systemic or intra-NAc infusion of the membrane-permeable GluR2 peptide prevented the expression of amphetamine-induced behavioral sensitization in the rat.     

Are all meticillin‐resistant Staphylococcus aureus (MRSA) equal in all hosts? Epidemiological and genetic comparison between animal and human MRSA

Meticillin-resistant Staphylococcus aureus (MRSA) continues to pose a major threat to human health. In animals, MRSA has become established as a veterinary pathogen in pets and horses; in livestock, it presents a concern for public health as a reservoir that can infect humans and as a source of transferrable resistance genes. Genetic analyses have revealed that the epidemiology of MRSA is different in different animal hosts. While human hospital-associated MRSA lineages are most commonly involved in pet infection and carriage, horse-specific MRSA most often represent 'traditional' equine S. aureus lineages. A recent development in the epidemiology of animal MRSA is the emergence of pig-adapted strains, such as CC398 and CC9, which appear to have arisen independently in the pig population. Recent insight into the genome structure and the evolution of S. aureus has helped to explain key aspects of these three distinct epidemiological scenarios. This nonsystematic literature review summarizes the structure and variations of the S. aureus genome and gives an overview of the current distribution of MRSA lineages in various animal species. It also discusses present knowledge about the emergence and evolution of MRSA in animals, adaptation to different host species and response to selective pressure from animal-specific environments. An improved understanding of the genetics and selective pressure that underpin the adaptive behaviour of S. aureus may be used in the future to predict new developments in staphylococcal diseases and to investigate novel control strategies required at a time of increasing resistance to antimicrobial agents.     

Activity of bleach, ethanol and two commercial disinfectants against spores of Encephalitozoon cuniculi

Encephalitozoon cuniculi is a small protist parasite in the phylum Microspora. Hosts are infected by ingestion or inhalation of spores passed in the urine or feces. Infection with E. cuniculi is usually asymptomatic, except in young or immunocompromised hosts. This study examined the effects of various disinfectants on in vitro infectivity of E. cuniculi spores. Spores of E. cuniculi were exposed to several dilutions of commercial bleach, 70% ethanol and dilutions of commercial disinfectants HiTor and Roccal for 10 min and then loaded onto human fibroblast cells (Hs68 cells). Ten minutes of exposure to these disinfectants was lethal to E. cuniculi spores. Additional exposure time studies were done using dilutions of bleach at 0.1, 1 and 10%, and 70% ethanol. Exposure of E. cuniculi spores to 1 or 10% bleach for 30s rendered them non-infectious for Hs68 cells. Growth of E. cuniculi was observed in Hs68 cells inoculated with spores treated with 0.1% bleach for 30s or 1, 3 and 5 min, but not with spores treated for 7 min or longer. Exposure of E. cuniculi spores to 70% ethanol for 30s rendered them non-infectious for Hs68 cells. Spores of E. cuniculi are more sensitive to disinfectants than are coccidial oocysts and other parasite cysts. The relatively short contact time needed to kill spores indicates that disinfection of animal housing may be a viable means to reduce exposure of animals to E. cuniculi spores.     

Coccidosis caused by Eimeria scabra in a finishing hog

Coccidiosis caused by Eimeria scabra was diagnosed in a 60-kg finishing hog with severe diarrhea and weight loss. Fresh and fixed tissues from a farrowing to finishing operation in eastern Georgia were submitted. Examination of hematoxylin-eosin-stained sections of small intestine revealed large numbers of thick-walled oocysts and large macrogamonts. Although coccidiosis has been associated with diarrhea in baby pigs, coccidiosis as a cause of diarrhea in finishing swine is seldom reported.