Giardiasis

• Giardia duodenalis (also known as G. intestinalis or G. lamblia)

• widespread protozoan parasite found in humans and animals, including dogs and cats

• currently 6 confirmed species (w/o selective host specificity)

• parasite occurrence: densely populated environments such as kennels, pet shops and animal shelters

• called The smiling parasite

the frequent detection of Giardia in dogs or cats poses the question whether the infection might also be transmitted to the animal owner?

• 1780 reported cases in 2022 in germany (must be reported)

• 4 pairs of flagella

• each pair of flagella contributes specifically to various modes of flagellar motility through differential movements

• anterior, posterior/lateral, caudal, ventral flagella

attach to the epithelium

main stages: cysts and trophozoites

in detail: cyst, excyzoite, encyzoite, trophozoites

• Mucus • Bacteria • Detritus

• Enzyme-linked immunosorbent assay (ELISA or DFA): —> stool antigen

• Nucleic acid amplification assay (NAAT): - detects and copies (amplifies) specific Giardia (DNA sequences)

• Stool microscopy:

  • evaluation of stool for trophozoites or cysts

  • Less sensitive than ELISA, DFA, or NAAT

• Variant-specific surface proteins (VSPs) cover the whole surface of the trophozoite

• (VSPs) on the parasite's surface, which are thought to enable immune evasion by adapting to the host's antibodies.