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Geng HL, Yan WL, Wang JM, Meng JX, Zhang M, Zhao JX, Shang KM, Liu J, Liu WH. Meta-analysis of the prevalence of Giardia duodenalis in sheep and goats in China. Microb Pathog 2023; 179:106097. [PMID: 37062491 DOI: 10.1016/j.micpath.2023.106097] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/01/2023] [Accepted: 04/01/2023] [Indexed: 04/18/2023]
Abstract
Giardia duodenum (G. duodenalis) can cause giardiasis and infect a variety of hosts. So far, there have been no detailed data regarding the positive rate of G. duodenalis in sheep and goats in China. Here, a systematic literature review was carried out to investigate the epidemiology of G. duodenalis in sheep and goats in China. To perform the meta-analysis, the databases CNKI, VIP, WanFang, PubMed, Web of science and ScienceDirect were employed for screening studies related to the prevalence of G. duodenalis in sheep and goats in China. The total prevalence of G. duodenalis in sheep and goats was estimated to be 7.00% (95% CI: 4.00-10.00). In the age subgroup, the prevalence of G. duodenalis in sheep and goats of >12 months (11.29%; 95% CI: 8.08-14.97) was higher than that in sheep and goats of ≤12 months (7.57%; 95% CI: 3.95-12.24). An analysis based on seasons showed that the prevalence of G. duodenalis in sheep and goats was higher in summer (11.90%; 95% CI: 0.50-35.05) than that in other seasons. The prevalence of G. duodenalis in sheep and goats after 2016 was 8.57% (95% CI: 5.34-11.79), which was higher than others. The highest prevalence of G. duodenalis in sheep and goats was 13.06% (95% CI: 6.26-19.86) recorded in Southwestern China. The prevalence of Giardia infection in sheep (7.28%; 95% CI: 2.30-14.73) was higher than that in goats (5.43%; 95% CI: 2.73-8.98). The NOAA's National Center for Environmental Information (https://gis.ncdc.noaa.gov/maps/ncei/cdo/monthly) was used to extract relevant geoclimatic data (latitude, longitude, elevation, temperature, precipitation, humidity, and climate). By analyzing the data of each subgroup, it was shown that region, genetype, and climate were potential risk factors for giardiasis prevalence in sheep and goats. Based on the analysis of common factors and geographical factors, it is recommended to strengthen effective management measures (e.g. ventilation and disinfection in warm and humid areas) and formulate relevant policies according to local conditions. Breeders should strengthen the detection of G. duodenalis in sheep and goats, customize corresponding control measures according to the diet and living habits of sheep and goats, and strengthen the protection of sheep and lamb calves, so as to reduce the incidence rate and reduce the economic loss of China's animal husbandry.
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Affiliation(s)
- Hong-Li Geng
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China
| | - Wei-Lan Yan
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China; College of Life Science, Changchun Sci-Tech University, Shuangyang, Jilin, PR China
| | - Jian-Min Wang
- Shandong New Hope Liuhe Group Co., Ltd., Qingdao, 266100, PR China
| | - Jin-Xin Meng
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China
| | - Miao Zhang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China
| | - Ji-Xin Zhao
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China
| | - Kai-Meng Shang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China
| | - Jing Liu
- College of Life Science, Changchun Sci-Tech University, Shuangyang, Jilin, PR China.
| | - Wen-Hua Liu
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, PR China.
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Wang X, Wang X, Cao J. Environmental Factors Associated with Cryptosporidium and Giardia. Pathogens 2023; 12:pathogens12030420. [PMID: 36986342 PMCID: PMC10056321 DOI: 10.3390/pathogens12030420] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/17/2023] [Accepted: 03/01/2023] [Indexed: 03/30/2023] Open
Abstract
Environmental factors significantly influence the transmission of intestinal protozoan diseases. Cryptosporidiosis and giardiasis are important zoonotic diseases characterized by diarrhea, and are mainly water or foodborne diseases caused by fecal-borne oocysts. The One Health approach effectively addresses environmentally influenced zoonotic diseases. However, the impact of environmental factors on the survival of Cryptosporidium/Giardia (oo)cysts or disease transmission is mostly uncharacterized. Associations between cryptosporidiosis and giardiasis incidence and environmental variables (e.g., climatic conditions, soil characteristics, and water characteristics) have been reported; however, the identified relationships are not consistently reported. Whether these are country-specific or global observations is unclear. Herein, we review the evidence for the influence of environmental factors on Cryptosporidium/Giardia and corresponding diseases from three perspectives: climatic, soil, and water characteristics. The (oo)cyst concentration or survival of Cryptosporidium/Giardia and the incidence of corresponding diseases are related to environmental variables. The associations identified varied among studies and have different levels of importance and lag times in different locations. This review summarizes the influence of relevant environmental factors on Cryptosporidium/Giardia from the One Health perspective and provides recommendations for future research, monitoring, and response.
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Affiliation(s)
- Xihan Wang
- Chinese Center for Tropical Diseases Research, School of Global Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), National Institute of Parasitic Diseases, Shanghai 200025, China
- Key Laboratory of Parasite and Vector Biology, National Health Commission of the People's Republic of China, Shanghai 200025, China
- World Health Organization Collaborating Center for Tropical Diseases, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University-The University of Edinburgh, Shanghai 200025, China
| | - Xu Wang
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), National Institute of Parasitic Diseases, Shanghai 200025, China
- Key Laboratory of Parasite and Vector Biology, National Health Commission of the People's Republic of China, Shanghai 200025, China
- World Health Organization Collaborating Center for Tropical Diseases, Shanghai 200025, China
| | - Jianping Cao
- Chinese Center for Tropical Diseases Research, School of Global Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), National Institute of Parasitic Diseases, Shanghai 200025, China
- Key Laboratory of Parasite and Vector Biology, National Health Commission of the People's Republic of China, Shanghai 200025, China
- World Health Organization Collaborating Center for Tropical Diseases, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University-The University of Edinburgh, Shanghai 200025, China
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Piveteau P, Druilhe C, Aissani L. What on earth? The impact of digestates and composts from farm effluent management on fluxes of foodborne pathogens in agricultural lands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 840:156693. [PMID: 35700775 DOI: 10.1016/j.scitotenv.2022.156693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/10/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
The recycling of biomass is the cornerstone of sustainable development in the bioeconomy. In this context, digestates and composts from processed agricultural residues and biomasses are returned to the soil. Whether or not the presence of pathogenic microorganisms in these processed biomasses is a threat to the sustainability of the current on-farm practices is still the subject of debate. In this review, we describe the microbial pathogens that may be present in digestates and composts. We then provide an overview of the current European regulation designed to mitigate health hazards linked to the use of organic fertilisers and soil improvers produced from farm biomasses and residues. Finally, we discuss the many factors that underlie the fate of microbial pathogens in the field. We argue that incorporating land characteristics in the management of safety issues connected with the spreading of organic fertilisers and soil improvers can improve the sustainability of biomass recycling.
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Prevalence of Protozoan Parasites Cryptosporidium sp. and Callimastix equi in the Edible Oyster Saccostrea cucullata and Its Relationship with Selected Water Quality Parameters in Sundarbans Region of West Bengal, India. Acta Parasitol 2022; 67:1254-1259. [PMID: 35679007 DOI: 10.1007/s11686-022-00578-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/12/2022] [Indexed: 11/01/2022]
Abstract
PURPOSE Prevalence of protozoan parasites Cryptosporidium sp. and Callimastix equi in the edible oyster resources Saccostrea cucullata, and its relationship with selected water quality parameters such as temperature, pH and salinity in Sundarbans region of West Bengal, India, have been assessed and discussed elaborately. METHODS Edible oysters S. cucullata were collected randomly from the selected study site Frasergunj of Sundarbans region and protozoan parasites such as Cryptosporidium sp. and C. equi were isolated, stained and determined its prevalence. Relationship of water temperature, pH and salinity with the prevalence of protozoan parasite had been assessed and analyzed. RESULTS Prevalence of infection of Cryptosporidium sp. is much more than the C. equi found in S. cucullata. The infections of the parasites are higher during monsoon then pre-monsoon season. Significant negative correlation (P < 0.05) occurs between pH of water and prevalence of Cryptosporidium sp. and C. equi in the edible oyster S. cucullata collected from Frasergunj of Sundarbans region, South 24 Parganas of West Bengal. The C. equi parasite follows a seasonal pattern of infection varying significantly with salinity (P < 0.01) of the water in the edible oyster, S. cucullata collected from Frasergunj of South 24 Parganas of West Bengal. CONCLUSION These results indicate that the Cryptosporidium sp. and C. equi contamination is accompanying with public health risks if edible oysters are consumed uncooked of undercooked. Extremes and/or rapid fluctuations of important environmental factors such as water temperature, salinity, pH can seriously compromise oyster health and outcome of aquaculture.
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Taggart PL, Stevenson MA, Firestone SM, McAllister MM, Caraguel CGB. Spatial Analysis of a Cat-Borne Disease Reveals That Soil pH and Clay Content Are Risk Factors for Sarcocystosis in Sheep. Front Vet Sci 2019; 6:127. [PMID: 31069240 PMCID: PMC6491573 DOI: 10.3389/fvets.2019.00127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/03/2019] [Indexed: 11/13/2022] Open
Abstract
Cat-borne parasites and their associated diseases have substantial impacts on human, livestock, and wildlife health worldwide. Despite this, large and detailed datasets that allow researchers to study broad-scale trends in the ecology of cat-borne diseases are either difficult to obtain or non-existent. One condition that is easily detected at slaughter is macroscopic sarcocystosis, a cat-borne parasitosis of sheep (Ovis aries). We conducted a cross-sectional study to describe the geographic distribution of sarcocystosis in sheep throughout South Australia and investigate ecosystem characteristics associated with the presence of disease. Data were obtained from two slaughterhouses which processed 3,865,608 sheep from 4,204 farms across 385,468 km2 of South Australia's land mass for the period 2007-2017. A Poisson point process model was developed to quantify environmental characteristics associated with higher densities of sarcocystosis-positive farms. Sarcocystosis was highly clustered on a large island off of the Australian coast and the density of sarcocystosis-positive farms increased in areas of low soil pH (intensity ratio: 0.86, 95% CI: 0.78, 0.95) and high clay content. We hypothesize that region was confounded by, and predominately acted as a proxy for, cat density. Our results have broader implications regarding the health, welfare, economic, and conservation impacts of other cat-borne parasitosis, such as toxoplasmosis.
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Affiliation(s)
- Patrick L Taggart
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Mark A Stevenson
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Simon M Firestone
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Milton M McAllister
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Charles G B Caraguel
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
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George CM, Burrowes V, Perin J, Oldja L, Biswas S, Sack D, Ahmed S, Haque R, Bhuiyan NA, Parvin T, Bhuyian SI, Akter M, Li S, Natarajan G, Shahnaij M, Faruque AG, Stine OC. Enteric Infections in Young Children are Associated with Environmental Enteropathy and Impaired Growth. Trop Med Int Health 2017; 23:26-33. [PMID: 29121442 DOI: 10.1111/tmi.13002] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To investigate the relationship between faecal contamination in child play spaces, enteric infections, environmental enteropathy (EE) and impaired growth among young children. METHODS A prospective cohort study was conducted of 203 children 6-30 months of age in rural Bangladesh. Stool samples were analysed by quantitative PCR for Shigella, Enterotoxigenic Escherichia coli (ETEC), Campylobacter jejuni, Giardia intestinalis and Cryptosporidium spp. Four faecal markers of intestinal inflammation were also measured: alpha-1-antitrypsin, myeloperoxidase, neopterin and calprotectin. Child growth was measured at baseline and 9 months after enrolment. E. coli was measured in soil in child play spaces. RESULTS Forty-seven percent of study children had three or more enteric pathogens in their stool. Thirty five percent (71/203) of children had Shigella, 30% (61/203) had ETEC, 73% (148/203) had C. jejuni, 79% (160/203) had Giardia intestinalis and none had Cryptosporidium. Children with ETEC had significantly higher calprotectin concentrations (Coefficient: 1.35, 95% Confidence Interval [CI]: 1.005, 1.82). Children with Shigella had a significantly higher odds of being stunted at our 9-month follow-up (OR: 2.01, 95% CI: 1.02, 3.93). Children with Giardia intestinalis had significantly higher E.coli counts in the soil collected from their play spaces (OR: 1.23, 95% CI: 1.02, 1.48). CONCLUSION Enteric infections were significantly associated with EE and impaired growth in rural Bangladesh. These findings provide further evidence to support the hypothesis that contaminated soil in child play spaces can lead to enteric infections, many of which are likely subclinical, resulting in EE and impaired growth in young children.
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Affiliation(s)
- Christine Marie George
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Vanessa Burrowes
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Jamie Perin
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Lauren Oldja
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Shwapon Biswas
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.,Department of Internal Medicine, Rangpur Medical College Hospital, Rangpur, Bangladesh
| | - David Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Shahnawaz Ahmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Nurul Amin Bhuiyan
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Tahmina Parvin
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Mahmuda Akter
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Shan Li
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Gayathri Natarajan
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Mohammad Shahnaij
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Abu G Faruque
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - O Colin Stine
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
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Kinyua MN, Wald I, Camacho-Céspedes F, Izurieta R, Haas CN, Ergas SJ. Does the use of tubular digesters to treat livestock waste lower the risk of infection from Cryptosporidium parvum and Giardia lamblia? JOURNAL OF WATER AND HEALTH 2016; 14:738-753. [PMID: 27740541 DOI: 10.2166/wh.2016.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Worldwide, high incidences of cryptosporidiosis and giardiasis are attributed to livestock waste. Quantitative microbial risk assessment can be used to estimate the risk of livestock related infections from Cryptosporidium parvum and Giardia lamblia. The objective of this paper was to assess the occupational and public health risks associated with management of raw and anaerobically digested livestock waste in two rural communities in Costa Rica based on fomite, soil and crop contamination and livestock waste management exposure pathways. Risks related to cattle waste were greater than swine waste due to cattle shedding more (oo)cysts. Cryptosporidium parvum also posed a greater risk than Giardia lamblia in all exposure pathways due to livestock shedding high loads of Cryptosporidium parvum oocysts and oocysts' lower inactivation rates during anaerobic digestion compared with Giardia lamblia cysts. The risk of infection from exposure to contaminated soil and crops was significantly lower for a community using tubular anaerobic digesters to treat livestock waste compared to a community where the untreated waste was applied to soil. The results indicate that treatment of livestock waste in small-scale tubular anaerobic digesters has the potential to significantly decrease the risk of infection below the World Health Organization's acceptable individual annual risk of infection (10-4).
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Affiliation(s)
- Maureen N Kinyua
- Department of Civil and Environmental Engineering, University of South Florida, 4202 E Fowler Ave ENB 118, Tampa, FL 33620, USA E-mail: ; Present address: Department of Earth and Environmental Engineering, Columbia University, 500 W. 120th St. 918 S. W. Mudd Hall, 500, Manhattan, NY 10027, USA
| | - Ileana Wald
- Department of Civil and Environmental Engineering, University of California, 760 Davis Hall Berkeley, Berkeley, CA 94720, USA
| | - Fabricio Camacho-Céspedes
- University of Georgia, Costa Rica, Apartado 108-5655 Santa Elena de Monteverde, Puntarenas, Costa Rica
| | - Ricardo Izurieta
- Department of Global Health, University of South Florida, 4202 E Fowler Ave CPH 1127, Tampa, FL 33620, USA
| | - Charles N Haas
- Department of Civil, Architectural and Environmental Engineering, Drexel University, 251 Curtis Hall, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Sarina J Ergas
- Department of Civil and Environmental Engineering, University of South Florida, 4202 E Fowler Ave ENB 118, Tampa, FL 33620, USA E-mail:
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Boyer DG, Kuczynska E. Prevalence and Concentration ofCryptosporidiumOocysts in Beef Cattle Paddock Soils and Forage. Foodborne Pathog Dis 2010; 7:893-900. [PMID: 20353289 DOI: 10.1089/fpd.2009.0480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Douglas G. Boyer
- Appalachian Farming Systems Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beaver, West Virginia
| | - Ewa Kuczynska
- Appalachian Farming Systems Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beaver, West Virginia
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Ramirez NE, Wang P, Lejeune J, Shipitalo MJ, Ward LA, Sreevatsan S, Dick WA. Effect of tillage and rainfall on transport of manure-applied Cryptosporidium parvum oocysts through soil. JOURNAL OF ENVIRONMENTAL QUALITY 2009; 38:2394-2401. [PMID: 19875795 DOI: 10.2134/jeq2008.0432] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Most waterborne outbreaks of cryptosporidiosis have been attributed to agricultural sources due to the high prevalence of Cryptosporidium oocysts in animal wastes and manure spreading on farmlands. No-till, an effective conservation practice, often results in soil having higher water infiltration and percolation rates than conventional tillage. We treated six undisturbed no-till and six tilled soil blocks (30 by 30 by 30 cm) with 1 L liquid dairy manure containing 10(5) C. parvum oocysts per milliliter to test the effect of tillage and rainfall on oocyst transport. The blocks were subjected to rainfall treatments consisting of 5 mm or 30 mm in 30 min. Leachate was collected from the base of the blocks in 35-mL increments using a 64-cell grid lysimeter. Even before any rain was applied, approximately 300 mL of water from the liquid manure (30% of that applied) was transported through the no-till soil, but none through the tilled blocks. After rain was applied, a greater number and percentage of first leachate samples from the no-till soil blocks compared to the tilled blocks tested positive for Cryptosporidium oocysts. In contrast to leachate, greater numbers of oocysts were recovered from the tilled soil, itself, than from the no-till soil. Although tillage was the most important factor affecting oocyst transport, rainfall timing and intensity were also important. To minimize transport of Cryptosporidium in no-till fields, manure should be applied at least 48 h before heavy rainfall is anticipated or methods of disrupting the direct linkage of surface soil to drains, via macropores, need to be used.
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Affiliation(s)
- Norma E Ramirez
- Food Animal Health Research Program, The Ohio State University, Wooster, OH 44691, USA
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Abstract
Cryptosporidium parvum is a zoonotic protozoan that infects many different mammals including cattle and humans. Cryptosporidiosis has become a concern for dairy producers because of the direct losses due to calves not performing well and the potential for environmental contamination with C. parvum. Identifying modifiable control points in the dynamics of infection in dairy herds will help identify management strategies that mitigate its risk. The quantitative risk assessment approach provides estimates of the risk associated with these factors so that cost-effective strategies can be implemented. Using published data from epidemiologic studies and a stochastic approach, we modeled the risk that C. parvum presents to dairy calves in 2 geographic areas: 1) the New York City Watershed (NYCW) in southeastern New York, and 2) the entire United States. The approach focused on 2 possible areas of exposure--the rearing environment and the maternity environment. In addition, we evaluated the contribution of many risk factors (e.g., age, housing, flies) to the end-state (i.e., total) risk to identify areas of intervention to decrease the risk to dairy calves. Expected risks from C. parvum in US dairy herds in rearing and maternity environments were 41.7 and 33.9%, respectively. In the NYCW, the expected risks from C. parvum in the rearing and maternity environments were 0.36 and 0.33%, respectively. In the US scenarios, the immediate environment contributed most of the risk to calves, whereas in the NYCW scenario, it was new calf infection. Therefore, within the NYCW, risk management activities may be focused on preventing new calf infections, whereas in the general US population, cleaning of calf housing would be a good choice for resource allocation. Despite the many assumptions inherent with modeling techniques, its usefulness to quantify the likelihood of risk and identify risk management areas is illustrated.
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Affiliation(s)
- D V Nydam
- Department of Population Medicine and Diagnostic Science, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Abstract
Of 155 species of mammals reported to be infected with Cryptosporidium parvum or C. parvum-like organisms most animals are found in the Orders Artiodactyla, Primates, and Rodentia. Because Cryptosporidium from most of these animals have been identified by oocyst morphology alone with little or no host specificity and/or molecular data to support identification it is not known how many of the reported isolates are actually C. parvum or other species. Cryptosporidiosis is a cause of morbidity and mortality in animals and humans, resulting primarily in diarrhea, and resulting in the most severe infections in immune-compromised individuals. Of 15 named species of Cryptosporidium infectious for nonhuman vertebrate hosts C. baileyi, C. canis, C. felis, C. hominis, C. meleagridis, C. muris, and C. parvum have been reported to also infect humans. Humans are the primary hosts for C. hominis, and except for C. parvum, which is widespread amongst nonhuman hosts and is the most frequently reported zoonotic species, the remaining species have been reported primarily in immunocompromised humans. The oocyst stage can remain infective under cool, moist conditions for many months, especially where water temperatures in rivers, lakes, and ponds remain low but above freezing. Surveys of surface water, groundwater, estuaries, and seawater have dispelled the assumption that Cryptosporidium oocysts are present infrequently and in geographically isolated locations. Numerous reports of outbreaks of cryptosporidiosis related to drinking water in North America, the UK, and Japan, where detection methods are in place, indicate that water is a major vehicle for transmission of cryptosporidiosis.
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Affiliation(s)
- Ronald Fayer
- United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
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