Animal Waste, Water Quality and Human Health

32Animal Waste, Water Quality and Human Healthantibodies were found in up to 100% of sea otters, 50% of seals, 100% of dolphins,and 61.1% in sea lions (Dubey et al. 2003). These epidemiological surveys are agood indicator of the extensive environmental contamination with T. gondiioocysts through infected raw chicken meat, raw beef, bird, free rangingdomestic cats, and other mechanical vectors including flies, cockroaches, dungbeetles, and earthworm.Toxoplasma is a cosmopolitan parasite in humans. Seroprevalence rates varyaccording to geographical distribution, sample size and diagnostic methods.Based on epidemiological surveillance in general populations, approximately30% in USA and the United Kingdom, 50–80% in Europe, 30% in Asia, 60% inSouth Africa, and 70% in South America are seropositive for Toxoplasmainfection. The prevalence of human toxoplasmosis appears to be higher in lessdeveloped countries, in humid environment and plains, in adults and in personsin close contact with soil and animals. In the last two decades, watercontamination with T. gondii has been implicated as a source of endemictoxoplasmosis (Carme et al. 2009) with outbreaks at both small (Palanisamyet al. 2006) and large (Bowie et al. 1997) scale worldwide. Acute infection in apreviously uninfected pregnant woman can lead to a wide spectrum of clinicaldisease in congenitally infected children. Mild disease may consist of slightlydiminished vision whereas severe cases may have eye, brain, and other organinvolvement in the infant. Acute infection can also lead to ocular lesions andsome loss of vision. Encephalitis, as a result of the reactivation of chronicT. gondii infection, is the most severe form of toxoplasmosis inimmuno-suppressed patients and is a major cause of death in AIDS patients(Nissapatorn et al. 2004).Blastocystis species RANK 3 Blastocystis is an emerging pathogen whoselife cycle involves polymorphic stages including vacuolar, granular, amoebicand cystic forms (Zierdt 1991, Tan & Suresh 2006). Blastocystis infectioncauses diarrhoea, bloating of the stomach and other gastrointestinal symptomswith recent studies showing the existence of pathogenic and nonpathogenic“strains” (Tan et al. 2008). The organism has been shown to be present in awide range of both captive and farm animals including birds (Boreham &Stenzel 1993, Abe et al. 2002). The prevalence of infection in animal workers ishigher (44%) than in the normal population (17%) (Suresh et al. 2001),suggesting that close proximity with animals may facilitate transmission (RajahSalim et al. 1999).Blastocystis subtypes from humans and animals have been shown to have lowhost-specificity, comprising isolates from humans and various animal hosts. Anumber of studies provide evidence for zoonotic transmission of the parasite andcross-transmissibility among heterogeneous hosts (Abe 2004, Noël et al. 2005,