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Table 2 Detection of parasite DNA, parasite load and histopathological changes in foetal brains and placental tissues from sheep and serological analysis of the foetuses after challenge infection with the Nc-Spain7 isolate at mid-gestation

From: Influence of dose and route of administration on the outcome of infection with the virulent Neospora caninum isolate Nc-Spain7 in pregnant sheep at mid-gestation

Group Animal id. Foetal death (days pi)a Placentomes/cotyledonsb Foetal brain
Foetus/lamb 1 Foetus/lamb 2 Foetus/lamb 3 Foetus/lamb 4
HPc DNAe qPCRf IFATd HPc DNAe qPCRf IFATd HPc DNAe qPCRf IFATd HPc DNAe qPCRf IFATd HPc DNAe qPCRf
Group 1 (105 tachyzoites, IV) 1.1 38 +++ 6/6 2030.18 ± 2021.53 1:32 +++ 3/3 47.53 ± 22.41 1:256 * 0/3 0.01         
1.2 40 +++ 6/6 1990.74 ± 543.90 1:256 ++ 2/3 3.40 ± 3.01             
1.3 40 ++ 6/6 3355.17 ± 2407.07 1:1024 +++ 3/3 8.47 ± 2.67             
1.4 37 ++ 6/6 2028.50 ± 2434.11 1:128 ++ 2/3 14.42 ± 13.01 1:256 +++ 3/3 584.97 ± 403.74 1:32 * 3/3 97.72 ± 109.14 β β β β
1.5 35 +++ 6/6 3296.38 ± 1231.41 1:64 +++ 3/3 141.14 ± 69.34 1:32 * 3/3 56.18 ± 27.50         
1.6 38 +++ 6/6 7974.29 ± 4660.05 1:1024 ++ 2/3 13.26 ± 15.57 1:1024 ++ 3/3 16.86 ± 10.67         
Group 2 (104 tachyzoites, IV) 2.1 32 +++ 6/6 7420.68 ± 6570.82 1:256 ++ 3/3 13.38 ± 6.04             
2.2   NA 4/4γ 3992.48 ± 1562.24γ 1:800 + 2/3 5.16 ± 5.59 β β β β β β β β     
2.3 32 +++ 6/6 4548.31 ± 4733.95 1:128 + 3/3 19.61 ± 12.04             
2.4 37 + 6/6 1930.36 ± 2034.10 1:256 ++ 2/3 5.54 ± 6.06 β β β β         
2.5 42 +++ 6/6 6829.41 ± 3917.31 1:64 + 3/3 2.70 ± 0.86 1:64 ++ 3/3 20.29 ± 8.74 NA ++ 3/3 11.97 ± 10.24 1:128 ++ 3/3 3.31 ± 2.49
Group 3 (103 tachyzoites, IV) 3.1 39 ++ 6/6 12 260.49 ± 9266.82 1:32 ++ 3/3 9. 48 ± 5.47 1:256 ++ 3/3 23.56 ± 13.52         
3.2 42 ++ 6/6 7370.42 ± 9178.25 1:256 ++ 3/3 2.27 ± 0.73 1:512 ++ 0/3 0.01         
3.3 44 ++ 6/6 2307.22 ± 1754.57 1:256 ++ 3/3 39.60 ± 43.86 1:128 ++ 0/3 0.01         
3.4   NA 5/6 62.07 ± 95.88 1:400 ++ 2/3 3.07 ± 2.72 1:400 ++ 2/3 3.33 ± 3.52 1:200 + 0/3 0.01 1:256 + 1/3 0.67 ± 1.15
3.5   NA 6/6 823.41 ± 714.63 1:1024 ++ α 3/3 7.74 ± 3.20 1:256 + 3/3 6.54 ± 0.30 1:64 ++ 3/3 15.91 ± 7.92     
Group 4 (102 tachyzoites, IV) 4.1   NA 6/6 1334.88 ± 561.06γ 1:400 + 3/3 12.44 ± 7.18 1:64 * 3/3 37.24 ± 17.02         
4.2   NA 6/6 6160.29 ± 4646.09γ 1:400 + 1/3 1.22 ± 2.11             
4.3 35 ++ 6/6 2101.24 ± 1290.86γ 1:512 ++ 3/3 23.03 ± 3.12 1:1024 ++ 3/3 14.35 ± 12.77         
4.4 42 ++ 6/6 3226.22 ± 2350.13γ 1:512 ++ 3/3 45.58 ± 22.09 1:128 ++ 3/3 20.07 ± 13.80         
Group 5 (104 tachyzoites, SC) 5.1   NA 6/6 65.40 ± 27.49γ 1:800 + 3/3 3.87 ± 1.85 1:200 + 1/3 0.65 ± 1.12 1:800 + 3/3 7.22 ± 5.87     
5.2 35 + 6/6 707.20 ± 614.80 1:512 ++ 3/3 16.07 ± 2.49 1:256 ++ α 2/3 2.62 ± 2.31         
5.3 32 +++ 6/6 38 294.17 ± 23 816.82 1:512 +++ 3/3 114.35 ± 34.34             
5.4 37 + 6/6 781.48 ± 444.87γ 1:128 + 3/3 6.32 ± 5.64 1:256 ++ 3/3 2.81 ± 1.58         
Group 6 (uninfected) 6.1   NA 0/6 0.01 0/3 0.01 0/3 0.01         
6.2   NA 0/6 0.01 0/3 0.01 0/3 0.01         
6.3   NA 0/6 0.01 0/3 0.01             
  1. aDay post-challenge when foetal death was detected by ultrasonography. The remaining foetuses lived until the end of the experiment
  2. bPlacentomes in ewes that aborted and cotyledons in ewes that gave birth; “NA” samples from cotyledons were not evaluated for histopathology
  3. cHistopathological lesion severity: none detected/unrelated (−), mild lesions (+) (in placentome, 0–33.3% of the placentome show lesions; in foetal brain, presence of local encephalitis), moderate lesions (++) (in placentome, 33.3–66.6% of the placentome show lesions; in foetal brain, presence of diffuse encephalitis) and severe lesions of ovine neosporosis (+++) (in placentome, 66.6–99.9% of the placentome show lesions; in foetal brain, presence of diffuse encephalitis and necrosis). * Autolysed; α No histopathological changes were found in one of the slides analysed
  4. dIFAT IgG antibody titres in foetal body fluids and in precolostral serum collected after birth in lambs born alive; “NA” not available
  5. eFractions represent the number of positive samples by nested PCR/number of samples examined
  6. fMean parasite load (tachyzoites/mg tissue) and standard deviation (SD). Considering that the N. caninum detection limit by real-time PCR is 0.1 parasites, negative samples (0 parasites) were represented as 0.01
  7. βMummified foetuses were not evaluated for any of the parameters
  8. γSamples from placental tissues exhibiting DNA degradation were excluded from parasite detection and/or parasite load analysis