Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 3 uppsatser.

To investigate the potential of chemotherapeutants to control the oyster pathogen Perkinsus marinus, anticoccidial and antifungal compounds were tested in vitro on infected hemolymph and cultured P. marinus cells and in vivo on infected oysters. In addition, acute toxicity to oysters was determined for six anticoccidials. In vitro experiments with infected hemolymph consisted of 24 h exposure of 0.2 mL hemolymph aliquots to concentrations ranging from 100 mg/L to 0.01 mg/L of amphotericin-B, amprolium, arprinocid, cycloheximide, lasalocid, malachite green, monensin, sulfadimethoxine, and a potentiated sulfadimethoxine, followed by incubation in fluid thioglycollate medium (FTM) to determine prezoosporangia abundance. Lasalocid, malachite green, and amphotericin-B were the most effective compounds reducing prezoosporangia abundance, relative to the untreated control group, at concentrations as low as 10 mg/L. Cycloheximide, monensin, and to a lesser extent sulfadimethoxine, were also effective but only at the highest concentration tested (100 mg/L). In vitro experiments with cultured P. marinus consisted of 24 h exposure of 10&\sp5& cells to 100 mg/L, 10 mg/L, and 1 mg/L of amphotericin-B, and 100 mg/L of cimetidine, cycloheximide, fumagillin, 5-fluorocytosine, ketoconazole, lasalocid, and monensin, followed either by incubation in FTM to determine abundance and size of prezoosporangia, or by addition of Neutral Red to determine cell viability. Amphotericin-B, lasalocid, and monensin were effective in reducing prezoosporangia abundance, size, and/or cell viability. No effects of cycloheximide on cultured cells were apparent. Lasalocid, monensin, and malachite green, were toxic to oysters at concentrations below 10 mg/L. The 96-hr. LC50 for lasalocid was 0.59 mg/L. No median lethal dose was determined for monensin or malachite green, but oyster mortality resulted from exposures ranging from 1 mg/L to 10 mg/L of either compound. In three in vivo experiments, infected oysters were exposed to amprolium, arprinocid, cycloheximide, lasalocid, monensin, malachite green, potentiated sulfadimethoxine, and sulfadimethoxine at various concentrations. Only cycloheximide was effective in reducing P. marinus infections. After 15 days of exposure to 10 mg/L of cycloheximide, weighted prevalence significantly declined from 3.78 in untreated controls to 2.10 in treated oysters. Infections progressed after treatment was discontinued as indicated by an increase in weighted prevalence from 0.71 at the end of treatment to 1.31 one month later. (Abstract shortened by UMI.).

No description available.

American oyster (Crassostrea virginica) stocks on the East Coast in general, and in Chesapeake Bay in particular, have been in decline over the past half-century in large part due to Dermo disease, caused by the protist parasite Perkinsus marinus. Efforts to restore oysters for their ecological and economic value have centered on the development and use of hatchery-based seed selectively bred for disease resistance. Selective breeding could benefit from the incorporation of oysters from wild stocks that have developed "natural Dermo resistance", but few such stocks have been identified and verified. This dissertation describes reciprocal common-garden experiments carried out at two sites in each of the Gulf of Mexico and the Chesapeake Bay between fall 1999 and winter 2001. The experiments compared growth, disease intensity, and survival of seed from putatively disease resistant and susceptible populations in both the Gulf of Mexico and Chesapeake Bay. In the Gulf experiment, oysters from Gulf stocks showed increased survival and decreased disease intensity, determined by body burden analysis of parasite cell counts, compared to Chesapeake stocks. Survival and disease intensities showed statistically significant, but slight differences among stocks of Gulf origin and among stocks of Chesapeake origin. There was no significant difference in growth over the eighteen months of the experiment. The Chesapeake study also showed lower infection intensity and decreases mortality attributable to Dermo disease in Gulf stocks. There were also significant differences in disease intensity and survival among Chesapeake stocks. Additionally, the stock from Rappahannock River, VA showed increased growth compared to other stocks. In an additional study, oysters from the Chesapeake Bay study were used to determine if an association existed between disease intensity (body burden) and host defense activity, as measured by a suite of assays, including hemocyte counts, granulocyte percentage, hemocyte killing ability, serum protein concentration, and serum lysozyme activity. Development of two new assays, serum inhibition of P. marinus protease, and serum inhibition of P. marinus activity, was begun, but require additional refinement. No strong correlation or association was found, but a seasonal component was apparent in several defense assays, as well as in disease intensity. This work has identified and verified wild stocks that have been incorporated into existing breeding programs for both restoration and the development of commercial aquaculture in Chesapeake Bay and the Gulf of Mexico. The existence of disease resistant wild stocks also suggests that the conservation of wild oysters is a viable alternative or addition to current hatchery-based restoration efforts.

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Salmonellosis is a serious problem of public health that mainly infants, young children and people with immunodeficiencies face. Human direct contact with animals is one of the possible ways of transmission of the disease. An increasing trend of keeping exotic pets, including amphibians and reptiles, has been observed for recent years in the United States and developing European countries. Most of these animals are asymptomatic carriers of Salmonella. However, in this review we introduced new and the most dangerous outbreaks of salmonellosis caused by contact with amphibians and reptiles that appeared in all continents in last ten years. It was demonstrated that Salmonella strains isolated from cold-blooded animals such as animals and reptiles differ genetically from strains isolated from humans. It means that the reason of appearance of Salmonella outbreaks caused by transmission of pathogens from amphibians or reptiles to human are genetic changes including the activation of virulence factors that cause pathogenicity in humans. It is supposed that popularity of keeping amphibians and reptiles as pets has caused an increase in the demand for these animals and in the international trade of these species. The problem is also caused by breeder's unconsciousness of proper procedures of keeping exotic animals in a household. Therefore, the World Health Organization (WHO) has censored the most important issues to minimize the risk of salmonellosis, focusing mainly on RAS salmonellosis (reptile – associated salmonellosis), because this disease is the most common in the United States. It is estimated that about 74,000 of the United States citizens are getting infected by Salmonella strains transmitted from reptiles kept as pets every year. Educating people on this topic is a key preventive method of salmonellosis. This review can help future breeders how to keep reptiles and amphibians according to recommendation of World Health Organization.

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Master of Veterinary Bioscience / Department of Diagnostic Medicine/Pathobiology / Deon Van Der Merwe / Every year thousands of domestic animals are poisoned by ethylene glycol. Exposure is normally orally, but may be dermal, and poisonings are usually accidental and not malicious. Antifreeze, overwhelmingly the source of the ethylene glycol poisoning, is responsible for over 99% of reported cases. Storage, handling and proper disposal of ethylene glycol is extremely important in limiting access to this deadly product. Ethylene glycol exposures were involved in 1737 calls made to the American Society for the Prevention of Cruelty to Animals call center between 2006 and 2011. Dogs were involved in approximately 87% of exposures and cats in 13%. There were no seasonal or breed patterns. The most common clinical signs reported were neurological and gastrointestinal for both cats and dogs. Urinary calcium oxalate crystals were reported in 28.6% of exposed cats, and 21% of dogs. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to detect calcium oxalate crystals in wax-mounted kidneys from twenty total cases, ten of which were suspected ethylene glycol poisoning submitted to the Kansas State Veterinary Diagnostic Laboratory, and ten samples deemed negative by a pathologist using light microscopy. Pure calcium oxalate monohydrate was used as a reference, and a unique absorption peak was detected between wavenumbers 1290 cm[superscript]-1 and 1320 cm[superscript]-1. The drying of kidney tissues resulted in increased sensitivity for calcium oxalate. Crystal detection by the ATR-FTIR was compared to light microscopy. Bi-fringence of crystals allowed microscopic detection, but the ATR-FTIR specificity for the test was 100%, and sensitivity was 80% compared to traditional microscopy for ca-oxalate crystal identification. ATR-FTIR was also used to detect un-metabolized ethylene glycol in vomitus using wavenumbers 1084 cm[superscript]−1, 1039 cm[superscript]−1, and 882 cm[superscript]−1, but ethylene glycol was not detectable. Ethylene glycol concentrations in samples were much too low to be detected as ethylene glycol on the ATR-FTIR, as the limit of detection was not distinguishable until 5000 ppm using a serial dilution. These methods presented simple, reliable, quick, sensitive, stable, and highly adaptable tests for detection, diagnosis and treatment of ethylene glycol poisoning.