in vitro culture and isoenzyme analysis of giardia lamblia

1.4 Distribution
The morbidity and misery of giardiasis is experienced world-wide because of the
ubiquity of Giardia. The global prevalence Was reported to be 200 million in 1993
(Crompton & Savioli, 1993). It is the most common protozoan cause of diarrhoea
in the United States (Wolfe, 1979; Isaac-Renton, 1991) and is the most frequently
reported intestinal parasite of humans in the United Kingdom, (a prevalence of
1,8% of 835 asymptomatic adults screened in a study in Manchester by
Kaczmarski & Jones was reported in 1989). In the United States 3,9% of more
than 300 000 submitted stool samples (with prevalence values as high as 16% in
some areas), were documented (Hill, 1990) and a mean annual rate of infection
per annum was reported to be 4,6 per 10 000 population (Flanagan, 1992). In
Australia 250 asymptomatic pre-school children in Sydney had a prevalence of
infection of 6,8% (Walker et al., 1986) and a rate of 20,2 per 100000 population
was reported (Kaczmarski & Jones, 1989). In Great Britain, an incidence of 0,9 per
10 000 population annually was reported (Flanagan, 1992).
Prevalence varies between 40% in South America, the
Caribbean, the Middle East and South East Asia. In a study in Egypt, 100% of the
population was found to be infected over a six month study period (Flanagan,
1992). In contrast, in most developed countries of Western Europe, Australia, New
Zealand, and North America, prevalences of between 2 and 7% are more common
(Farthing et al., 1986; Flanagan, 1992). However, Giardia infections still have an
impact on public health problems in these countries.
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