Occurrence and distribution of Giardia species in wild rodents in Germany

Parasites & Vectors

Table 2 Relative Giardia abundance in rodent samples. Relative Giardia abundance in rodent samples was determined by semi-quantitative IFA and by analysis of ct-values of Giardia positive samples in a Giardia specific qPCR assay^a

Genus	Species	Ct values (qPCR)			Semi-quantitative cyst abundance (IFA)^c absolute numbers (%) [95% CI]
		Median (Range)^b	95% CI	n	+	++	+++	n
Apodemus	agrarius	33.9 (23.5–38.1)	32.2–35.4	18	8 (100) [63.1–100]	0 (0) [0–36.9]	0 (0) [0–36.9]	8
	flavicollis	32.9 (23.9–39.9)	30.7–35.6	12	6 (86) [42.1–99.6]	1 (14) [0.4–57.9]	0 (0) [0–40.0]	7
	sylvaticus	no ct			5 (100) [47.8–100]	0 (0) [0–52.2]	0 (0) [0–52.2]	5
Total^d		33.4 (23.5–39.9)	32.4–34.6	34	22 (96) [78.1–99.8]	1 (4) [0–21.9]	0 (0) [0–14.8]	23
Microtus	agrestis	28.1 (22.9–36.3)	27.5–29.1	58	43 (80) [66.5–89.4]	10 (19) [9.3–31.4]	1 (2) [0.1–12.3]	54
Microtus	arvalis	29.0 (20.9–38.3)	28.4–30.0	97	57 (58) [47.2–67.5]	28 (28) [19.7–38.2]	14 (14) [8.0–22.6]	99
Total^d		28.5 (20.9–38.3)	28.4–29.5	163	104 (70) [62.7–77.9]	25 (17) [11.3–24.1]	18 (12) [7.4–18.6]	147
Myodes	glareolus	30.7 (22.8–39.9)	30.4–31.2	274	149 (64) [57.7–70.4]	50 (21) [16.4–27.4]	33 (14) [10.0–19.4]	232

Abbreviations: Ct threshold cycle, IFA immunofluorescence assay, n sample size, qPCR real-time PCR, 95% CI 95% confidence interval
^aOne should note that parasite excretion is often not uniform. However, it is assumed that such effects averaged out by analyzing the means of different groups
^bSignificant differences of median-values analyzed by non-parametric Kruskal-Wallis test (H = 53.8, P < 0.0001). Post-hoc test, Dunn’s test of multiple comparisons using rank sums: Ct-values were different between genera (Apodemus vs Microtus P < 0.0001, Apodemus vs Myodes P < 0.0001, Microtus vs Myodes P < 0.0001; mean ranks for Apodemus= 353.9, for Microtus=183.5 and for Myodes=252.6). There were no significant differences within the species of the same genus
^cFecal samples were distributed on slides using inoculation loop (~ 10 μl) and analyzed by IFA. Cyst amount of the samples were semi-quantified (1–10 cysts (+), 11–50 cysts (++), > 50 cysts (+++). Comparison of (+) vs (++/+++) between groups was done using Fisher’s exact test followed by multiple testing correction (Bonferroni-Holm procedure): Apodemus vs Microtus (P = 0.019); Apodemus vs Myodes (P = 0.005); Microtus vs Myodes (P = 0.218)
^dAnimals for which only genus could be determined were included

ISSN: 1756-3305