The authors present the actual informations on waterborne outbreaks of giardiosis as well as the evidences of Giardia cyst transmission by municipal water supply. In the article a recommendation is given to molecular biology techniques which contributed to the armentarium applied in the modern diagnostics of giardiosis.
Two commercial faecal antigen tests, based on Giardia specific antigens, were compared with traditional microscopical examination of faeces in 40 clinical patients, including 14 patients with a confirmed Giardia infection as well as in a survey among 96 children in four day care centers. The results obtained with these faecal antigen tests were not much better than by using traditional microscopy by a well trained parasitologist. Specific Giardia antigen (GSA 65) has been still detected in faeces up to day 4th after treatment of giardiosis, when microscopical examination of faeces was already for a few days negative. The Giardia antigen detection test was not very useful in examining the unconcentrated duodenal content.
In man, as well as in many species of vertebrates there exist several populations of Giardia duodenalis group which, though morphologically indistinguishable, show different level of heterogenicity in several characteristics, a. o. in surface antigens, isoenzyme make-up, RFLP, invasiveness for different hosts or pattern of experimental infection. Also the clinical observations in man distinctly suggested that G. intestinalis comprises several different populations. In the course of giardiosis apparent variability in clinical manifestations can be observed. In many patients the infection is symptomless and resolves spontaneously and in some others – variable intensity of symptoms is observed. Most likely both the parasit's characteristics and the host's feature will determine the clinical character of infection. It is well known that in some cases it is the host that responsible for the symptoms of the infection. Thus, for instance, clinical giardiosis links with immunodeficiency, malnutrition or young age. There are also evidences that some Giardia isolates have enhanced potency to provoke the disease of the host. It is considered that the variable pattern of the infection may be related to three different factors in host-parasite relationship: extra- and intrapopulation variability of Giardia isolates, the microenvironmental factors of the host's intestine, and the variable immune response of the host. The author describes data on the two first factors.
Ornidazole (Tiberal La Roche) was used in 50 persons infected with Giardia intestinalis in the dosis of 500 mg twice a day during 5 days. Examinations were performated after 7-10 days, having been repeated one month and 3 months later. A positive results were achieved after one month in 46 cases (92%) and after 3 months in 45 cases (90%). Tiberal is thought to be effective drug in the treatment of Giardiosis, causing no side effect apart from headache and nausea occurring sporadically.