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Barwick, R. S., Mohammed, H. O., McDonough, P. L., & White, M. E. (1998). Epidemiologic features of equine Leptospira interrogans of human significance. Prev Vet Med, 36(2), 153–165.
Abstract: Leptospirosis is a zoonotic bacterial disease caused by Leptospira interrogans. There is a serologic evidence that horses are exposed to L. interrogans and, as a shedder of these organisms, can be a threat to humans. We examined risk factors associated with the risk of testing seropositive to three L. interrogans serovars (L. icterohaemorrhagiae, L. grippotyphosa, and L. canicola) in the horses of New York State, in order to understand the epidemiology of the disease and suggest strategies to control and prevent equine leptospirosis. To carry out this study, blood samples were collected from a random sample of 2551 horses and tested for the presence of antibodies to the above serovars using the microscopic agglutination test. Samples with a titer $100 were considered positive. Clinical and demographic data were collected on each horse, the farms' management practices and ecology. Logistic regression analysis was used to develop a multivariate indexing system and to identify factors significantly associated with the risk of leptospirosis. Four indices were developed based on the possible sources of exposure: rodent exposure index; wildlife exposure index; soil and water index; and management index. The soil and water index was significantly associated with the risk of exposure to all three serovars. Management was positively associated with L. icterohaemorrhagiae and L. canicola. Density of horses turned out together was positively associated with the risk of exposure to L. grippotyphosa. We concluded that indirect exposure of horses to L. interrogans through contaminated soil and water appears to be significantly associated with the risk of exposure to all three serovars. Management appears to play an important role in the exposure to L. interrogans. Modification of management practices might reduce the horses' risk of exposure and hopefully minimize the human hazards.
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Kida, H. (1997). [Ecology of influenza viruses in animals and the mechanism of emergence of new pandemic strains]. Nippon Rinsho, 55(10), 2521–2526.
Abstract: Ecological studies on influenza viruses revealed that the hemagglutinin genes are introduced into new pandemic strains from viruses circulating in migratory ducks through domestic ducks and pigs in southern China. Experimental infection of pigs with 38 avian influenza virus strains with H1-H13 hemagglutinins showed that at least one strain of each HA subtype replicated in the upper respiratory tract of pigs. Co-infection of pigs with a swine virus and with an avian virus generated reassortant viruses. The results indicate that avian viruses of any subtype can contribute genes in the generation of reassortants. Virological surveillance revealed that influenza viruses in waterfowl reservoir are perpetuated year-by-year in the frozen lake water while ducks are absent.
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Atwill, E. R., Mohammed, H. O., & Lopez, J. W. (1996). Evaluation of travel and use as a risk factor for seropositivity to Ehrlichia risticii in horses of New York state. Am J Vet Res, 57(3), 272–277.
Abstract: OBJECTIVES--To determine whether mean annual frequency and destination of equine travel was associated with exposure to Ehrlichia risticii and whether these associations were modified by horses' place of residence. DESIGN--Cross-sectional study. SAMPLE POPULATION--511 equine operations containing 2,587 horses were visited in New York state from a target population of 39,000 operations. PROCEDURE--Each horse was tested for serum antibodies against E risticii, using indirect fluorescent antibody. Information on the horse's travel history, farm's management practices, and surrounding ecology was obtained by personal interview and resource maps. Statistical analyses were performed on 2 cohorts of animals: all horses enrolled in the study and horses born on the property or that resided at least 4 years on the farm. Three county-based risk regions (RR) were identified by use of cluster analysis. RESULTS--Mean seroprevalence for each of the 3 RR was 2.4 (low risk), 8.5 (moderate risk), and 18.5% (high risk) for cohort 1 and 2.5, 8.0, and 18.4% for cohort 2. Among cohorts 1 and 2, pleasure riding and breeding trips were associated with exposure to E risticii, but horse residence (low, moderate, or high RR) was an effect modifier for these associations. Among cohort 1 and stratifying the analysis according to the RR for the travel destination, trail riding at low RR and trail riding at high RR were associated with exposure. Among cohort 2 and stratifying the analysis according to the RR for the travel destination, breeding trips were associated with exposure, and strong effect modification was present for horse residence (low, moderate, or high RR). CONCLUSIONS--Only certain types of travel to specific RR were associated with higher risk of exposure to E risticii. In many instances, travel was not associated, or was associated, with a reduced risk of exposure.
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Straatsma, G., Samson, R. A., Olijnsma, T. W., Op Den Camp, H. J., Gerrits, J. P., & Van Griensven, L. J. (1994). Ecology of Thermophilic Fungi in Mushroom Compost, with Emphasis on Scytalidium thermophilum and Growth Stimulation of Agaricus bisporus Mycelium. Appl Environ Microbiol, 60(2), 454–458.
Abstract: Twenty-two species of thermophilic fungi were isolated from mushroom compost. Scytalidium thermophilum was present in the compost ingredients, fresh straw, horse droppings, and drainage from compost and dominated the fungal biota of compost after preparation. Of 34 species of thermophilic fungi tested, 9 promoted mycelial growth of Agaricus bisporus on sterilized compost: Chaetomium thermophilum, an unidentified Chaetomium sp., Malbranchea sulfurea, Myriococcum thermophilum, S. thermophilum, Stilbella thermophila, Thielavia terrestris, and two unidentified basidiomycetes. These species will be considered for future experiments on inoculation and more controlled preparation of compost.
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Loyola, E. G., Rodriguez, M. H., Gonzalez, L., Arredondo, J. I., Bown, D. N., & Vaca, M. A. (1990). Effect of indoor residual spraying of DDT and bendiocarb on the feeding patterns of Anopheles pseudopunctipennis in Mexico. J Am Mosq Control Assoc, 6(4), 635–640.
Abstract: Intense and persistent use of DDT for malaria control has increased resistance and induced exophilic behavior of Anopheles pseudopunctipennis. An evaluation of bendiocarb and DDT to control this species in Sinaloa, Mexico, showed that, in spite of DDT-resistance, both insecticides produced similar effects. Feeding patterns were analyzed to explain these results. Resting mosquitoes were collected over the dry and wet seasons. Anophelines were tested in an ELISA to determine the source of the meals. The human blood index (HBI) ranged from 3.3 to 6.8% in DDT- and from 12.7 to 26.9% in bendiocarb-sprayed houses. Irritability and repellency in DDT-sprayed houses could explain the reduced HBI. In contrast, bendiocarb produced higher mortality. These effects could have affected different components of the vectorial capacity and similarly reduced malaria.
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Holzapfel, W. H., & Botha, S. J. (1988). Physiology of Sporolactobacillus strains isolated from different habitats and the indication of in vitro antagonism against Bacillus species. Int J Food Microbiol, 7(2), 161–168.
Abstract: In an ecological study only low numbers of Sporolactobacillus were found in habitats such as the faeces of herbivores, the rumen of cattle and the final waste water of an abattoir. Their presence in the final waste water of an abattoir indicates their possible association with food, and, more specifically, with meat. Differences were found in some physiological characteristics. One isolate (L2404) differed from the authentic Sporolactobacillus ATCC 15538 by its inability to ferment inulin, its growth in presence of 6.5% NaCl and in 0.2% tellurite, by the isomer(s) of lactic acid produced and the mol% G + G in the DNA. One Sporolactobacillus isolate (L2407) showed antagonism against Bacillus cereus, Bacillus cereus var, mycoides, Bacillus megaterium and Bacillus subtilis.
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Sudia, W. D., Fernandez, L., Newhouse, V. F., Sanz, R., & Calisher, C. H. (1975). Arbovirus vector ecology studies in Mexico during the 1972 Venezuelan equine encephalitis outbreak. Am J Epidemiol, 101(1), 51–58.
Abstract: Virus vector studies were conducted in the States of Durango, Chihuahua, and Tamaulipas, Mexico, in June and July 1972. Apparently only a low level of Venzuelan equine encephalitis (VEE) virus transmission to equines occured at the time of the study, and the infection was restricted to areas which had not experienced overt activity during the preceding year. The low level of infection was associated with a scarcity of mosquitoes. The IB (epidemic) strain of VEE virus was isolated from two pools of Anopheles pseudopunctipennis (Theo.) and the blood of one symptomatic equine. The low mosquito population, the relatively few equine cases observed, and the absence of reports of VEE human disease from the outbreak area suggested VEE virus persistence through a low-level mosquito-equine transmission cycle. Other studies have already indicated that wild vertebrates play no more than a minor role in outbreaks of epidemic VEE. Mosquito collections made in areas of the states of Durango, Chihuahua, and Tamaulipas, where considerable epidemic activity of VEE had occurred in 1971, failed to reveal evidence of VEE virus persistence. Twenty-nine ioslations of other arboviruses were also made in these studies: including 22 of St. Louis encephalitis virus (SLE), 2 of Flanders virus, 1 of Turlock virus, 1 of Trivittatus virus of the California Group, 1 of western equine encephalitis virus (VEE), and 2 (from Santa Rose) which possibly represent a hitherto unknown virus in the Bunyamwera Group. These are the first reports of SLE virus isolations from mosquitoes in Mexico, and the first demonstration of Trivittatus, VEE Turlock and Flanders viruses in Mexico from any source.
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Christensen, H. A., & Herrer, A. (1973). Attractiveness of sentinel animals to vectors of leishmaniasis in Panama. Am J Trop Med Hyg, 22(5), 578–584.
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Tempelis, C. H., & Nelson, R. L. (1971). Blood-feeding patterns of midges of the Culicoides variipennis complex in Kern County, California. J Med Entomol, 8(5), 532–534.
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Wilhelm, W. E., & Anderson, J. H. (1971). Vahlkampfia lobospinosa (Craig. 1912) Craig. 1913: rediscovery of a coprozoic ameba. J Parasitol, 57(6), 1378–1379.
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