Genotyping of Giardia isolates in Scotland: a descriptive epidemiological study

Giardiasis, caused by the intestinal protozoan parasite Giardia intestinalis (synonyms: G. lamblia, G. duodenalis), is one of the most frequent parasites to infect the Scottish population. Transmission of the infective cysts in faecal matter is commonly via food and/or water. Giardia is subdivided into assemblages, where clinical and epidemiological differences have been described between assemblages A and B. This snapshot descriptive epidemiological study examines 30 positive cases of Giardia of which 72% (n = 21) were shown to be assemblage A, 14% (n = 4) assemblage B and 10% (n = 3) mixed assemblages (A and B). There was a 2:3 female:male ratio of affected individuals with foreign travel recorded in 22 of these cases. The commonest symptom was diarrhoea which was reported in 80% of cases followed by tiredness. Five cases required hospitalization emphasizing the importance of gaining a greater understanding of how Giardia assemblages influence clinical outcomes to assist in formulating guidelines to manage potential Giardia outbreaks.