Pathogen Loading From Canada Geese Faeces in Freshwater: Potential Risks to Human Health Through Recreational Water Exposure

Canada geese (Branta canadensis) faeces have been shown to contain pathogenic protozoa and bacteria in numerous studies over the past 15 years. Further, increases in both the Canada geese populations and their ideal habitat requirements in the United States (US) translate to a greater presence of these human pathogens in public areas, such as recreational freshwater beaches. Combining these factors, the potential health risk posed by Canada geese faeces at freshwater beaches presents an emerging public health issue that warrants further study. Here, literature concerning human pathogens in Canada geese faeces is reviewed and the potential impacts these pathogens may have on human health are discussed. Pathogens of potential concern include Campylobacter jejuni, Salmonella Typhimurium, Listeria monocytogenes, Helicobacter canadensis, Arcobacter spp., Enterohemorragic Escherichia coli pathogenic strains, Chlamydia psitacci, Cryptosporidium parvum and Giardia lamblia. Scenarios presenting potential exposure to pathogens eluted from faeces include bathers swimming in lakes, children playing with wet and dry sand impacted by geese droppings and other common recreational activities associated with public beaches. Recent recreational water‐associated disease outbreaks in the US support the plausibility for some of these pathogens, including Cryptosporidium spp. and C. jejuni, to cause human illness in this setting. In view of these findings and the uncertainties associated with the real health risk posed by Canada geese faecal pathogens to users of freshwater lakes, it is recommended that beach managers use microbial source tracking and conduct a quantitative microbial risk assessment to analyse the local impact of Canada geese on microbial water quality during their decision‐making process in beach and watershed management.     

乳房炎源生鲜乳中病原微生物的污染现状及防控措施

主要介绍了乳房炎患病牛乳中病原微生物污染情况、耐药情况及防控措施。总结出乳房炎患病牛乳中的病原微生物种类较多, 主要有大肠杆菌、金黄色葡萄球菌、链球菌和克雷伯菌, 不同地区乳房炎乳样中的病原微生物不同, 产生的耐药性和耐药基因存在差异。旨在为减少因滥用和乱用抗生素导致药物残留和耐药性产生、降低乳房炎患病牛乳中病原微生物的污染以及科学、合理用药提供参考。     

Antimicrobial resistance of Salmonella and generic Escherichia coli isolated from surface water samples used for recreation and a source of drinking water in southwestern Ontario,Canada

Antimicrobial resistance (AMR) in the aquatic environment represents an important means of introduction and dissemination of resistance genes, and presence of resistant pathogens in surface waters may pose a public health concern to recreational and drinking water users. The purpose of this study was to explore antimicrobial resistance patterns in water samples collected from the Grand River watershed (southwestern Ontario, Canada) to describe the composition, trends and potential risks of AMR in the aquatic environment. As part of FoodNet Canada and the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), stream water samples were collected bi‐weekly from sampling sites within the Grand River watershed in the Waterloo, Ontario sentinel site and tested for the presence and antimicrobial susceptibility of Salmonella spp. (2005–2013) and generic Escherichia coli (2012–2013). Of all samples tested, 16% of Salmonella and 22% of E. coli isolates were resistant to at least one antimicrobial, including three Salmonella isolates and two E. coli isolates that were resistant to Category I antimicrobials, which are classified as very high importance for the treatment of serious bacterial infections in humans. The greatest proportion of resistant E. coli isolates were observed from the river site upstream of the drinking water intake, while the greatest proportion of resistant Salmonella isolates were from sites upstream in the watershed, and at one recreational water site. Salmonella resistance trends remained fairly stable between 2007 and 2013, with the exception of streptomycin and tetracycline which increased in 2010 and 2013. Continued surveillance of antimicrobial resistance patterns and exploration of risk factor data will allow for a better understanding of resistance transmission in the aquatic environment.     

The ecology of sandy beaches in Transkei

Data from an ecological survey of three sandy beaches in Transkei and from Gulu beach on the eastern Cape coast, South Africa, are presented. Physical parameters such as beach profile, sand particle size, Eh and carbonate content, as well as abundance, composition, biomass and distribution of the macrofauna and meiofauna were investigated. Beaches in Transkei are relatively small and are usually associated with estuarine systems. Substrate at Thompson's beach in northern Transkei was relatively coarse with relatively few macrofaunal species. Further south, beaches have fine to medium substrates and are characterized by a diverse macrofaunal community. Major changes in faunal composition occurred in Transkei and this was most evident for Mpande and Cebe beaches where a subtropical east-coast fauna was replaced by species characteristic of the southern Cape coast. Molluscs also became increasingly important southwards and replaced crustaceans as the most important group. Meiofauna was dominated by nematodes and harpac- ticoids on all beaches and there was an increase both in numbers and biomass southwards.     

Immunization of sheep with a combination of intiminγ, EspA and EspB decreases Escherichia coli O157:H7 shedding

Enterohaemorrhagic Escherichia coli O157:H7 are zoonotic pathogens associated with haemorrhagic colitis (HC) and the haemolytic uremic syndrome (HUS). Ruminants are the main reservoir of this organism and most outbreaks of E. coli O157:H7 infections are food borne. Food contamination by ruminant manure has been reported as the primary source of human infection, therefore inhibition of E. coli O157:H7 colonization and shedding in ruminants could control the risk of human exposure to this pathogen. In the present study a vaccine based on the translocon proteins EspA and EspB and the outer membrane adhesion factor intiminγ significantly reduced faecal shedding of E. coli O157:H7 by orally infected sheep. Protection correlates with serum antibody responses to the defined antigens and validates the targeting of these colonization factors. Whereas vaccination has been described in cattle, this is the first study describing a significant decrease in faecal shedding following systemic immunization of sheep.     

Environmental sources and transmission of Escherichia coli O157 in feedlot cattle

A study was conducted in 2 feedlots in southern Alberta to identify environmental sources and management factors associated with the prevalence and transmission of Escherichia coli O157:H7. Escherichia coli O157:H7 was isolated in preslaughter pens of cattle from feces (0.8%), feedbunks (1.7%), water troughs (12%), and incoming water supplies (4.5%), but not from fresh total mixed rations. Fresh total mixed rations did not support the growth of E. coli O157:H7 and E. coli from bovine feces following experimental inoculation. Within a feedlot, the feces, water troughs, and feedbunks shared a few indistinguishable subtypes of E. coli O157:H7. A few subtypes were repeatedly isolated in the same feedlot, and the 2 feedlots shared a few indistinguishable subtypes. The prevalence of E. coli O157:H7 in water troughs of preslaughter cattle in 1 feedlot was associated with season, maximum climatic temperatures the week before sampling; total precipitation the week before sampling, and coliform and E. coli counts in the water trough.     

Survival of faecal indicator bacteria in treated pig manure stored in clay-covered heaps in Vietnam

Small-scale pig farmers in Vietnam typically store manure in heaps covered by a layer of clay. However, the hygienic quality of manure applied to agricultural soil is uncertain as storage time is determined by the need for soil fertilizer. This study aimed to assess how the storage of pig manure added straw, lime stone or urea in heaps covered by clay affected the survival of faecal bacteria. E. coli was reduced from 4 log(10)CFU/g to below the detection limit within 2 weeks with 2% (w/w) urea (CO(NH(2))(2)) whereas other amendments were associated with limited E. coli reductions. Enterococcus spp. were not reduced in any heaps indicating possible re-growth and that enterococci should be used as hygiene indicators with caution. Follow-up research should document the practical conditions under which the farmer practice of storing manure with a clay cover can be utilized to obtain a bactericidal effect of ammonia and a safe product with high fertilizer value.     

The ecology of sandy beaches in southern Africa

The physical features, macrofauna and meiofauna of four exposed sandy beaches along the southern coast of South Africa were quantitatively investigated. All beaches had medium to fine sands with relatively poor to moderate macrofauna and very rich meiofauna. The results are compared with the present knowledge of the southern African coastline. Sandy beaches types around the southern African coastline are summarized according to geomorphology and wave action and three Zoogeographie provinces are recognized. The macrofauna is dominated by crustaceans, mostly scavengers, on the warmer east coast and by molluscs, mostly filterfeeders, on the temperate south coast. Relationships between diversity and abundance of macrofauna, beach slope and particle size are analysed in detail. Intertidal zonation of macrofauna is described and a zonation scheme based on crustaceans proposed. Relationships between meiofauna composition and particle size are described as well as intertidal distribution patterns of the meiofauna. The role of surf circulation patterns and macrofaunal food sources in determining beach trophic structure is emphasized.     

Giardia in shellfish-farming areas: detection in mussels, river water and waste waters

Giardia cyst contamination of mussels (Mytilus galloprovincialis), raw and treated waste waters and water from rivers that flow into four Galician estuaries (NW Spain), where bivalve molluscs are cultured for human consumption, was studied. The high prevalence of contamination in mussels (41.8%, n=184), raw waste water (90.9%, n=11), treated waste water (87.5%, n=16) and in samples of river water (85.7%, n=7), with cyst counts of 9.8-1800.0, 7.0-2541.0 and 1.0-29.3 cysts l(-1), respectively, illustrate the wide distribution of this enteropathogen in the environment and the potential risk to public health associated with the consumption of raw or undercooking bivalves and use of these estuaries for recreational purposes.     

Antimicrobial resistance in Campylobacter spp. isolated from Ontario sheep flocks and associations between antimicrobial use and antimicrobial resistance

The objectives of this study were to determine the prevalence of antimicrobial resistance (AMR) in faecal Campylobacter spp. from lambs and adult sheep and associations between antimicrobial use (AMU) and AMR. A total of 275 faecal samples collected during initial and final visits from 51 sheep flocks, including one feedlot, across southern Ontario were tested for the presence of Campylobacter spp. Campylobacter jejuni was detected in 52% (143/275) of the faecal samples, Campylobacter coli in 7% (19/275), Campylobacter lari in 1% (2/275) and 2% (4/275) were non-speciated Campylobacter. Broth microdilution was used to test antimicrobial susceptibility of 162 isolates to nine antimicrobials. Campylobacter jejuni isolates (n = 142) were resistant to tetracycline (39%), ciprofloxacin (4%), nalidixic acid (4%) and telithromycin (1%). C. coli isolates (n = 19) were resistant to tetracycline (74%), and azithromycin, clindamycin, erythromycin, and telithromycin (5%). The C. lari isolate displayed resistance to nalidixic acid. No statistically significant associations were found between AMU and AMR during multivariate modelling in this study.     

Drug use and antimicrobial resistance among Escherichia coli and Enterococcus spp. isolates from chicken and turkey flocks slaughtered in Quebec,Canada

An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of flocks) and spectinomycin in turkeys (42% of flocks). Virginiamycin was the antimicrobial most frequently added to the feed in both chicken and turkey flocks. At least 1 E. coli isolate resistant to third-generation cephalosporins was present in all chicken flocks and in a third of turkey flocks. Resistance to tetracycline, streptomycin, and sulfisoxazole was detected in > 90% of flocks for E. coli isolates. Antimicrobial resistance (AMR) was observed to bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, and tetracycline in both chicken and turkey flocks for Enterococcus spp. isolates. No resistance to vancomycin was observed. The use of ceftiofur at hatchery was significantly associated with the proportion of ceftiofur-resistant E. coli isolates in chicken flocks. In turkey flocks, ceftiofur resistance was more frequent when turkeys were placed on litter previously used by chickens. Associations between drug use and resistance were observed with tetracycline (turkey) in E. coli isolates and with bacitracin (chicken and turkey), gentamicin (turkey), and tylosin (chicken) in Enterococcus spp. isolates. Further studies are needed to provide producers and veterinarians with alternative management practices and tools in order to reduce the use of antimicrobial feed additives in poultry.     

Antimicrobial resistance in Escherichia coli isolated from brown rats and house shrews in markets,Bogor, Indonesia

The prevalence of antimicrobial resistance (AMR) in small mammals dwelling in the city was used as an indicator of AMR bacteria in the environment. We captured 87 small mammals (79 brown rats and 8 house shrews) in four markets, Bogor, Indonesia in October 2019, and we obtained 20 AMR Escherichia coli (E. coil) from 18 brown rats and two house shrews. Of these, eight isolates were determined to be multi-drug resistant (MDR) E. coli, suggesting the potential contamination of AMR E. coli in the markets in Bogor, Indonesia, and that mammals, including humans, are at risk of infection with AMR E. coli from environment.     

Cryptosporidia on dairy farms and the role these farms may have in contaminating surface water supplies in the northeastern United States

The prevalence and risk factors for shedding of cryptosporidia by dairy cattle and calves and the prevalence and risk factors for cryptosporidia in surface waters associated with dairy farms were determined for a well-defined watershed in the northeastern United States. Eleven dairy farms were enrolled in the study and subjected to monthly sampling over a 6-month period. Animal-, water-, and manure-management practices were determined by survey and fecal, on-farm water, and stream samples were obtained monthly and evaluated for the presence of cryptosporidia. Ninety-one percent of the dairy farms in our study had Cryptosporidium on their premises. Fifteen percent of the sampled calves 0–3 weeks of age were shedding cryptosporidia. The risk factors for calves shedding cryptosporidia were contact between calves and frequent bedding changes. The probability of shedding cryptosporidia decreased with age. Nine percent of farm-associated stream samples were cryptosporidia-positive. The single risk factor for detecting cryptosporidia in surface water was increasing frequency of spreading of manure on fields. The probability of detecting cryptosporidia in streams decreased as 5-day cumulative precipitation increased. There were no animal-associated or barnyard-management features associated with detecting cryptosporidia in farm-impacted streams.     

EM在肉牛养殖上的研究应用进展

EM(有效微生物)是含有多种有益微生物的复合制荆,在促进畜禽生长、提高畜禽抗病力、减轻粪尿恶臭以及改善生态环境方面均具有重要作用.作者对EM制剂的组成研制、使用方式、作用机理、在肉牛养殖上的应用及影响EM作用效果的因素等进行了综合阐述.认为应积极推广应用EM制剂,以促进养牛业健康持续发展.     

循环水养殖模式对水体微生物、蛋鸭粪便微生物和土壤微生物的影响

试验旨在研究循环水养殖模式对水体微生物、蛋鸭粪便微生物和土壤微生物的影响。分别采集样品检测饮水管、戏水池、排水沟、各级消化池的水样和鸭舍内粪样、运动场粪样及周边土壤样品,采用平板计数法检测微生物数量。结果表明:(1)与排水沟的微生物数量相比,各级消化池和饮水管的大肠杆菌数分别降低28.13%、32.42%、40.98%和33.94%,"沙门+志贺"氏菌数分别降低13.75%、53.13%、82.5%和79.38%,均差异极显著(P<0.01);(2)与鸭舍内粪便微生物数量相比,运动场的大肠杆菌数和"沙门+志贺"氏菌数分别增加3.08%和2.29%,但差异不显著(P>0.05),土壤的大肠杆菌数和"沙门+志贺"氏菌数分别降低9.00%和3.70%,均差异不显著(P>0.05)。由此可知,循环水养殖模式能显著减少各级消化池和饮水管中病原微生物的数量。     

Risk factors associated with the presence of viable Listeria monocytogenes in bulk tank milk from US dairies

The objective of the study was to screen a large number of herd management practices and herd characteristics from US dairies to identify herd-level risk factors associated with the presence of Listeria monocytogenes in bulk tank milk (BTM). A total of 71 variables was univariately evaluated for their association with the presence of L. monocytogenes in BTM. Results from the univariate analysis indicated that using automatic take offs and having an open herd management increased the risk of BTM contamination with L. monocytogenes, while storing manure in outside pens not accessible to cattle decreased the risk. These variables, however, were not sustained in the multivariable model, which indicated that the presence of L. monocytogenes in BTM was significantly associated with region of the country (farms in the southeast and northeast were six and four times more likely respectively, to have BTM contamination than farms in the west) and number of milking cows (herds with >500 milking cows were five times more likely to have BTM contamination than herds with <100 milking cows). In conclusion, our results suggest that risk factors associated with BTM contamination are different depending on the geographical region and herd size of the operation.     

Water as a vector for infectious stages of parasites in livestock

Water is a key factor in the life cycle of many parasite species. The development of the free-living generation (oocysts, cysts, eggs, larvae) and the longevity of the resulting infectious stages are extremely dependent on the availability of water. Damp stables are principally associated with an increased risk of parasite infection. Infectious stages may accumulate in dirty watering equipment and in pools of water on pasture. Utilization of surface water, especially when contaminated with sewage or effluent from sewage plants, imposes an increased risk of parasite infection on farm animals. Flooding of pastures with water containing parasite stages can lead to extensive contamination. Rainfall, flooding or inadequate land disposal of manure may contaminate surface water with parasite stages of animal origin from adjacent agricultural areas.     

Studies on the Psammolittoral Meiofauna of Algoa Bay,South Africa

Two beaches in Algoa Bay, South Africa, have been found to support a relatively rich and varied meio-fauna. Highest numbers were recorded at HW on the sheltered beach (2 250/10 cm¹) and the lowest numbers at LW on the same beach (60/10 cm¹). On the exposed beach numbers were more uniform but were highest between MW and LW. Distribution of the meiofauna on the sheltered beach was limited mainly by the amounts of available oxygen in the interstitial water while on the exposed beach amounts of available food, and to a lesser extent oxygen, were limiting. The meiofauna of the sheltered beach was dominated by nematodes and that of the exposed beach by Crustacea (harpacticoid cope-pods and mystacocarids). Meiofauna biomass values were highest in winter and lowest in summer. Macrofauna was richer on the exposed beach, mainly due to the sand mussel, Donax serra. Production estimates based on standing crop indicated that the meiofauna may account for 55 percent and 28 per cent of the total secondary production on the sheltered and exposed beaches respectively.     

Patterns of species richness in sandy beaches of South America

Species richness of the intertidal macroinfauna of exposed sandy beaches around South America is reviewed in relation to geographic location. This macroinfauna is dominated by cirolanid isopods (Excirolana), bivalves (Mesodesma and Donax) and opheliid and spionid polychaetes. In general, the upper shore of tropical and subtropical beaches is characterized by crabs (Ocypodidae), whereas on temperate beaches it is dominated by talitrid amphipods and cirolanid isopods. The middle shore is primarily occupied by cirolanids and bivalves, and hippid crabs, bivalves and amphipods dominate the lower beach. Generally, species richness increases from upper to lower beach levels. Studies carried out on exposed sandy beaches of south-central Chile (ca. 40°S) show that different beach states harbour differences in species richness, with the greatest species richness on dissipative beaches, and the least on beaches with reflective characteristics, a pattern also observed in Uruguay.     

Antimicrobial resistance in fecal generic Escherichia coli and Salmonella spp. obtained from Ontario sheep flocks and associations between antimicrobial use and resistance

The purpose of this study was to examine the prevalence and patterns of antimicrobial resistance (AMR) in enteric bacteria obtained from Ontario sheep flocks, and associations between antimicrobial use (AMU) and AMR. Forty-nine sheep producers participated for a 1-year interval between 2006 and 2008. Two-hundred and eighty-three pooled fecal samples were collected from the flocks during initial and final visits. Up to 3 isolates of Salmonella spp. and generic E. coli per pooled fecal sample were tested for susceptibility to 15 antimicrobials. Resistance was infrequent among Salmonella (0%, n = 7 isolates) and low among E. coli (13.1%; n = 849) isolates. A small number of isolates were resistant to antimicrobials classified as being of very high importance to human health. Tetracycline resistance was most frequently observed (12.0%). Logistic regression was used to model potential AMU (qualitative and quantitative) risk factors for tetracycline resistance in generic E. coli from final visits. Qualitative analysis indicated that the use of injectable sulfonamides [including trimethoprim-sulfonamide combinations (TMS)] and tetracycline in the feed and water were significantly associated with tetracycline resistance (OR = 2.6, P = 0.01; and OR = 4.8, P ≤ 0.01, respectively). Quantitative analysis also indicated that TMS exposure rate was significantly associated with tetracycline resistance, which varied depending on the exposure rate. The exposure rate of tetracycline in the feed and water was only significant after the removal of one influential flock, warranting further research examining flocks with higher tetracycline exposure rates. Although the prevalence of AMR in participating flocks was relatively low, risk factors for resistance were identified.