Detection of
            <i>Toxoplasma gondii</i>
            Oocysts in Drinking Water

Isaac-Renton, Judith L.; Bowie, William; King, Arlene; Irwin, G S; Ong, Corinne S. L.; Fung, Chang Phone; Shokeir, M. Omar; Dubey, J. P.

doi:10.1128/aem.64.6.2278-2280.1998

Cited by 133 publications

(45 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Human outbreaks of toxoplasmosis have also been linked to water contaminated by runoff from the surrounding terrain (Benenson et al., 1982; Bowie et al., 1997; de Moura et al., 2006; Palanisamy et al., 2006). However, no T. gondii oocyst was found in water samples taken during the investigation of the 1995 British Columbia outbreak (Isaac‐Renton et al., 1998). The outbreak occurred following a week of heavy rain, and T. gondii oocysts were detected in two of 23 scats or faeces collected from necropsied cougars ( F. concolor vancouverensis ) (Aramini et al., 1998).…”

Section: Methodsmentioning

confidence: 99%

“…Detection of oocysts in environmental samples is hampered by the low concentration of oocysts in soil and water, and by the lack of techniques with sufficient sensitivity to detect their presence (Rothe et al., 1985; Isaac‐Renton et al., 1998; Kourenti and Karanis, 2006; Dabritz et al., 2007a). The minimal infectious dose for pigs and mice is as low as a single oocyst (Dubey et al., 1996, 1997), and is believed to be of similar magnitude for humans.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Cats andToxoplasma: Implications for Public Health

Dabritz

Conrad

2010

Zoonoses and Public Health

240

140

View full text Add to dashboard Cite

Cats are popular as pets worldwide because they are easy to care for and provide companionship that enriches the lives of human beings. Little attention has been focused on their potential to contaminate the environment with zoonotic pathogens. One such pathogen, the protozoan parasite Toxoplasma gondii, rarely causes clinical manifestations in cats or immunocompetent humans; however, it can have serious adverse effects on human foetuses and immunocompromised patients. Many human infections are believed to be acquired from eating undercooked or raw meat, such as pork and lamb (Tenter et al. Int. J. Parasitol., 30, 2000, 1217; Dubey et al. J. Parasitol. 91, 2005, 1082). However, the prevalence of T. gondii infection in human populations that do not consume meat or eat it well-cooked suggests that the acquisition of infection from the environment, via oocysts in soil, water or on uncooked vegetables, is also important (Rawal. Trans. Royal Soc. Trop. Med. Hyg., 53, 1959, 61; Roghmann et al. Am. J. Trop. Med. Hyg., 60, 1999, 790; Chacin-Bonilla et al. Am. J. Trop. Med. Hyg., 65, 2001, 131). In the past 20 years, two changes occurred that significantly increased the size of the cat population in the USA. Pet cat ownership grew from 50 million to 90 million animals, and animal welfare activists created feeding stations for abandoned and free-roaming cats. As many cat owners allow their cats to deposit faeces outside and cats maintained in colonies always defecate outside, ample opportunity exists for T. gondii oocysts to enter the environment and be transmitted to humans. Prevention efforts should focus on educating cat owners about the importance of collecting cat faeces in litter boxes, spaying owned cats to reduce overpopulation, reducing the numbers of feral cats and promoting rigorous hand hygiene after gardening or soil contact.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cats andToxoplasma: Implications for Public Health

Dabritz

Conrad

2010

Zoonoses and Public Health

240

140

View full text Add to dashboard Cite

show abstract

“…Because of irregular and limited oocyst shedding, the main approach available for infection ratio in cats is through seroprevalence (Dubey 1994). Although the presence of oocysts is usually low, rare, occasional and difficult to be found in water and soil (Isaac‐Renton et al. 1998) they play an important role in human infection, as they are resistant to usual water treatment with chlorination and decantation (Dubey & Beattie 1988).…”

Section: Introductionmentioning

confidence: 99%

Toxoplasma gondiispreading in an urban area evaluated by seroprevalence in free‐living cats and dogs

Meireles¹,

Galisteo²,

Pompeu³

et al. 2004

Tropical Med Int Health

View full text Add to dashboard Cite

SummaryInfection by the protozoan parasite, Toxoplasma gondii is widely prevalent in humans and animals throughout the world. Transmission takes place mainly by ingestion of raw or undercooked meat that contains parasite cysts or by ingestion of oocysts excreted in cat faeces, which can contaminate water and raw vegetables. The incidence of toxoplasmosis in urban areas can thus be also related to environmental contamination with oocysts. A direct measure of this environmental contamination by oocyst counting is unfeasible for technical reasons. An interesting alternative for measuring T. gondii urban spreading is the seroprevalence in free-living urban animals, used as sentinels, once they are exposed to similar risks of Toxoplasma infection-like humans.With this aim, we tested serum samples from stray cats and dogs for antibodies to T. gondii by indirect haemagglutination assay (IHA) and enzyme-linked immunosorbent assay (ELISA). Antibodies to T. gondii were found in 40% (40 of 100) of the cats, less than the 50.5% (101 of 200) found in dogs by ELISA (P < 0.05). Haemagglutination showed low resolution and concordance, precluding their use for diagnosis of T. gondii infection compared with ELISA. The prevalence of T. gondii was lower among stray cats probably due to their selective alimentary habits and lower water and food intake. Toxoplasma gondii seroprevalence in stray dogs and cats could be an indirect indicator of the parasite spreading in urban areas.

show abstract

“…Despite the importance of this step, few studies have systematically evaluated methods for concentrating T. gondii from water, and as far as we are aware, no studies have evaluated methods for C. cayetanensis. Filtration has been used several times for investigating waterborne outbreaks (Rabold et al 1994;Isaac-Renton et al 1998;de Moura et al 2006) and conducting environmental occurrence studies (Sturbaum et al 1998;Lopez et al 2003). Filters are readily available, easy to use, and U.S. Environmental Protection Agency Method 1623, the standardized filter method used in the United States for concentrating Cryptosporidium and Giardia (U.S. Environmental Protection Agency 2005), is thought to work for other protozoan pathogens.…”

Section: Discussionmentioning

confidence: 99%

Concentrating Toxoplasma gondii and Cyclospora cayetanensis from surface water and drinking water by continuous separation channel centrifugation

Borchardt

Spencer

Bertz

et al. 2009

Journal of Applied Microbiology

View full text Add to dashboard Cite

Aims: To evaluate the effectiveness of continuous separation channel centrifugation for concentrating Toxoplasma gondii and Cyclospora cayetanensis from drinking water and environmental waters. Methods and Results: Ready‐to‐seed vials with known quantities of T. gondii and C. cayetanensis oocysts were prepared by flow cytometry. Oocysts were seeded at densities ranging from 1 to 1000 oocysts l−1 into 10 to 100 l test volumes of finished drinking water, water with manipulated turbidity, and the source waters from nine drinking water utilities. Oocysts were recovered using continuous separation channel centrifugation and counted on membrane filters using epifluorescent microscopy. Recovery efficiencies of both parasites were ≥84% in 10 l volumes of drinking water. In source waters, recoveries ranged from 64% to 100%, with the lowest recoveries in the most turbid waters. Method precision was between 10% and 20% coefficient of variation. Conclusion: Toxoplasma gondii and C. cayetanensis are effectively concentrated from various water matrices by continuous separation channel centrifugation. Significance and Impact of the Study: Waterborne transmission of T. gondii and C. cayetanensis presents another challenge in producing clean drinking water and protecting public health. Detection of these parasites relies on effectively concentrating oocysts from ambient water, otherwise false negatives may result. Validation data specific to T. gondii and C. cayetanensis concentration methods are limited. Continuous separation channel centrifugation recovers oocysts with high efficiency and precision, the method attributes required to accurately assess the risk of waterborne transmission.

show abstract

Detection of Toxoplasma gondii Oocysts in Drinking Water

Cited by 133 publications

References 5 publications

Cats andToxoplasma: Implications for Public Health

Cats andToxoplasma: Implications for Public Health

Toxoplasma gondiispreading in an urban area evaluated by seroprevalence in free‐living cats and dogs

Concentrating Toxoplasma gondii and Cyclospora cayetanensis from surface water and drinking water by continuous separation channel centrifugation

Contact Info

Product

Resources

About