Mixed Giardia duodenalis assemblage A and E infections in calves

Abstract

A molecular epidemiological study was conducted on 100 dairy (499 calves) and 50 beef (333 calves) farms in Belgium to estimate the prevalence of different Giardia duodenalis assemblages in calves younger than 10 weeks of age. Positive samples from the epidemiological study and from a previous clinical study were selected and genotyped based on the amplification of the b-giardin gene. To investigate the occurence of mixed assemblage A and E infections in calves, a novel assemblage-specific PCR was developed based on the triose-phosphate isomerase gene. The prevalence was 22% (95% Probability Interval (PI): 12-34%) in dairy calves and 45% (95% PI: 30-64%) in beef calves. In total, 120 Giardia-positive samples from dairy and beef calves collected in the epidemiological study and from clinically affected calves were identified based on the amplification of the b-giardin gene. Overall G. duodenalis assemblage E was more prevalent (in 64% of the samples), although the majority (59%) of the dairy calves were infected with G. duodenalis assemblage A. Furthermore, mixed G. duodenalis assemblage A and E infections were identified in 31% of the calf samples (n = 101) using the assemblage-specific PCR. We believe this is the first report of mixed infections in calves, and the results of the present study indicate that calves, although mainly infected with the host-specific G. duodenalis assemblage E, are frequently infected with the zoonotic assemblage A, either as a mixed or mono-infection, suggesting that calves might be underestimated as a potential zoonotic reservoir for human infections. Ó

Genotyping of Giardia duodenalis Cysts by New Real-Time PCR Assays for Detection of Mixed Infections in Human Samples

“…First, they can be used to get a better estimate of the occurrence of mixed infections in clinical samples, which is likely to be strongly underestimated. Indeed, using tpi assemblage-specific primers in a standard PCR protocol, it has been shown that 31% of the calf isolates can be identified as mixed assemblage A and E infections (13), and a similar proportion of mixed A and B infections was found in human and monkey isolates using the same approach (14,22). Here, by applying the more sensitive qPCR assays, we have shown that an even larger percentage of human stool samples (37 to 83%, depending on the sensitivities of the different assays) contained DNAs of both assemblages A and B.…”

Molecular typing ofGiardia duodenalisin humans in Queensland – first report of Assemblage E

“…All samples were typed at the triose phosphate isomerase (tpi) locus using assemblage A, B and E specific primers as previously described (Sulaiman et al 2003;Geurden et al 2008;Levecke et al 2009). A representative subset of samples were also amplified using a nested PCR and sequenced at the glutamate dehydrogenase (gdh) locus (n = 30) as described by Read et al (2004) and at the tpi (n = 27) locus using the assemblage-specific primers described above.…”

Cryptosporidium and Giardia associated with reduced lamb carcase productivity

“…The primary 186 PCR was performed as described by Sulaiman et al, (2003). For the second round 187 reaction, assemblage-specific primers and conditions for assemblage A (product ~332bp) 188 and E (product ~388bp) were used as previously described (Geurden et al, 2008; (2009), with PCR reaction mixtures described in an earlier study (Sweeny et al, 2011b). …”