Zoonotic Potential of Giardiasis in Domestic Ruminants

Abstract

This study was conducted to assess the prevalence and zoonotic potential of giardiasis in domestic ruminants. Prevalence of infection was 17.7% in sheep and 10.4% in cattle and was significantly higher in lambs and calves (35.6% and 27.7%, respectively). Naturally infected lambs released cysts intermittently for months. Giardia trophozoites from sheep had typical claw hammer-shaped median bodies and were successfully cultured in TYI-S-33 medium, and cytosolic, cytoskeletal, and membrane fractions exhibited protein profiles similar to human isolates (WB). Immunoblotting showed that sera from infected sheep recognized human Giardia, sera from patients with giardiasis recognized Giardia from sheep, and in both cases recognition involved antigenic proteins of similar molecular weight. Cyst output and clinical signs in ovine infection resemble human disease and the organisms infecting humans and ruminants are morphologically and antigenically similar. It is postulated that domestic ruminants may be a reservoir for human infection and vice versa, thus classifying giardiasis as a zooanthroponotic disease.

Transmission cycles of Giardia duodenalis in dogs and humans in Temple communities in Bangkok—A critical evaluation of its prevalence using three diagnostic tests in the field in the absence of a gold standard

“…M a n u s c r i p t 15 Younger dogs were significantly more likely to be Giardia positive by IFAT but this risk factor was not found to be significant using PCR. Previous studies have implicated that tests with a lower sensitivity may result in biased estimation of prevalence and associated risk factors in older animals where the intensity of cyst excretion is lower (Buret et al, 1990;Olson et al, 1997). Dogs that were allowed to scavenge and those that were not fed commercial diets were at significantly higher risk of being Giardia positive by IFAT and PCR respectively.…”

“…Furthermore, diagnostic tests with a low sensitivity may also result in a biased estimation of prevalence and associated risk factors in older animals such as cattle for example, where cyst excretion is lower (Buret et al, 1990;Olson et al, 1997).…”

Cryptosporidium parvum(Eucoccidiorida: Cryptosporiidae) in calves: results of a longitudinal study in a dairy farm in Sfax, Tunisia

“…Mémoire Parasite, 2007, 14, 309-312 sible that with only one sample that the prevalence may have been somewhat underestimated (Buret et al, 1990;Ralston et al, 2003). Longitudinal studies have demonstrated that following animals over time will affect prevalence rates considerably.…”

Prevalence of Giardia and Cryptosporidium andersoni and their effects on performance in feedlot beef cattle

“…are two of the most common protozoan parasites distributed world wide, infecting a wide variety of mammalian hosts (Wolfe 1992;Zajac 1992;Scott et al 1994;Olson et al 1995). Hosts are infected with Giardia through the ingestion of cysts either by the fecal -oral route or the consumption of contaminated water (Meyer 1985;Buret et al 1990;Xiao 1994). Once ingested, the cysts excyst in the duodenum, releasing trophozoites that divide by longitudinal binary fisson, colonizing the small intestine of the host (Kirkpatrick and Farrell 1982;Wolfe 1992;Olson et al 1995).…”