The seven farms evaluated had goats that were positive for anti-T. gondii antibodies during the experimental period. In total, 66 matrices goats were evaluated, of which 47% (31/66) (95% CI: 34.6% − 59.7%) were positive; and their 93 female offspring, among which 61,3% (57/93) (95% CI: 52.4% − 69.2%) were positive at some point during the evaluation period.
The titers presented by the positive matrices goats in the IFAT ranged from 1:64 to 1:1024. Among the 57 offspring, that were positive at some point during the experimental period, the titers ranged from 64 to 2048 over the study period, as described in Table 1. In the first month of life, it was observed that 52,6% (30/57) (95% CI: 39.4% -59.3%) of the offspring showed anti-T. gondii antibodies. It was found that 93,5% (29/31) (95% CI: 74.3% -97.3%) of the offspring that were seropositive in the first month of life were born from positive mothers. Tthe mother's title has correlation with titration of offspring until four months of age (Fig. 2).
Table 1
Titers among female offspring that were positive for anti-T. gondii antibodies in the indirect fluorescence antibody test (IFAT), according to age in months, during the experimental period, on seven goat farms in the semiarid region of northeastern Brazil.
Farms | Antibody titer for mother | Identification of offspring | Months of age |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
P1 | 256 | 102F1 | 64 | 256 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P1 | < 64 | 122F1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 512 | 512 | 128 | NC |
P2 | 512 | 202F1 | 512 | 512 | 256 | 256 | 1024 | 512 | 256 | 0 | 0 | NC | NC | NC |
P2 | < 64 | 206F1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 128 | 64 | 0 | NC | NC |
P2 | 256** | 207F2** | 512 | 512 | 0 | 1024 | 512 | 512 | 128 | 64 | 64 | 0 | 0 | 0 |
P2 | 256 | 208F1 | 64 | 64 | 0 | 0 | 64 | 128 | 0 | 0 | 0 | 0 | 0 | NC |
P2 | < 64 | 209F2 | 0 | 0 | 0 | 0 | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 |
P2 | 512 | 210F1 | 1024 | 1024 | 128 | 64 | 0 | 0 | 0 | 0 | 128 | 64 | 0 | 0 |
P2 | 1024 | 211F1 | 1024 | 2048 | 512 | 128 | 64 | 64 | 512 | 128 | 128 | NC | NC | NC |
P3 | < 64 | 304F1 | 0 | 0 | 0 | 0 | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 |
P3 | 64 | 305F1 | 0 | 0 | 256 | 128 | 128 | 128 | 64 | 64 | 64 | 0 | 0 | 0 |
P3 | < 64** | 601F2** | 0 | 0 | 512 | 256 | 64 | 64 | 64 | 0 | 0 | 0 | 0 | 0 |
P3 | < 64 | 602F1 | 0 | 0 | 0 | 0 | 64 | 64 | 64 | 64 | 0 | 0 | 0 | 128 |
P3 | < 64** | 603F1** | 0 | 0 | 512 | 512 | 256 | 128 | 64 | 0 | 0 | 0 | 0 | 0 |
P3 | < 64 | 603F2** | 0 | 0 | 0 | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P3 | < 64 | 604F1 | 0 | 0 | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | NC |
P3 | 64*** | 606F1*** | 0 | 0 | 0 | 512 | 512 | 128 | 0 | 0 | 0 | 0 | 0 | 0 |
P3 | 64 | 606F2*** | 0 | 0 | 0 | 64 | 64 | 128 | 64 | 0 | 0 | 0 | 0 | 0 |
P3 | 512 | 26F1 | 256 | 256 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P3 | 512 | 77F2 | 1024 | 1024 | 1024 | 512 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 |
P3 | 512 | 78F1 | 2048 | 1024 | 256 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P4 | < 64 | 850F1 | 0 | 128 | 256 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P4 | < 64 | 851F1 | 0 | 0 | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P4 | 64 | 852F1 | 0 | 0 | 256 | 256 | 256 | 256 | 64 | 0 | 0 | 0 | 0 | 0 |
P5 | 512*** | 24F3*** | 1024 | 1024 | 512 | 128 | 64 | 1024 | 512 | 128 | 64 | 64 | 64 | 0 |
P5 | 64** | 32F2** | 512 | 512 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 |
P5 | 512** | 30F1** | 512 | 128 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 |
P6 | < 64 | 250F1 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | NC | NC |
P6 | 64** | 012F1** | 64 | 0 | 0 | 0 | 1024 | 512 | 128 | 128 | 64 | 0 | 0 | 0 |
P6 | 64 | 012F2** | 512 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P6 | < 64 | 07F1 | 512 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P6 | 1024** | 10F1** | 512 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P6 | 1024 | 10F2** | 1024 | 512 | 256 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 |
P6 | 512 | 09F1** | 0 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P6 | 512** | 09F2** | 64 | 64 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | NC | NC | NC |
P6 | 1024** | 43F1** | 64 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | NC | NC |
P6 | 1024 | 43F2** | 1024 | 512 | 512 | 128 | 64 | 0 | 0 | 0 | 0 | 0 | NC | NC |
P6 | < 64** | 44F1** | 0 | 0 | 0 | 0 | 0 | 128 | 128 | 64 | 64 | 0 | 0 | 0 |
P6 | < 64 | 44F2** | 0 | 0 | 0 | 64 | 64 | 0 | 256 | 64 | 64 | 0 | 0 | 0 |
P6 | 512 | 46F1 | 1024 | 1024 | 1024 | 512 | 256 | 256 | 128 | 128 | 0 | 0 | 0 | NC |
P7 | 128 | 59F1 | 64 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | 512 | 45F1 | 128 | 128 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | 128 | 48F1 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | < 64 | 57F1 | 0 | 0 | 0 | 0 | 0 | 64 | 64 | 64 | NC | NC | NC | NC |
P7 | < 64 | 50F1 | 0 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | NC | NC | NC |
P7 | 512 | 38F1 | 128 | 128 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | NC |
P7 | < 64** | 03F2** | 0 | 0 | 128 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | < 64 | 280F1 | 0 | 0 | 0 | 0 | 0 | 128 | 128 | 64 | 64 | 0 | 0 | 0 |
P7 | < 64** | 018F1** | 256 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | < 64 | 11GAF1 | 0 | 0 | 512 | 256 | 256 | 256 | 128 | 64 | 64 | 64 | 64 | 0 |
P7 | 512 | 16F1 | 1024 | 256 | 128 | 64 | 64 | 64 | 64 | 64 | NC | NC | NC | NC |
P7 | 64 | 17F1 | 0 | 0 | 0 | 0 | 0 | 0 | 1024 | 512 | 128 | 128 | 128 | 128 |
P7 | < 64 | 056F1 | 0 | 0 | 0 | 0 | 0 | 128 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | < 64 | 12F2** | 0 | 0 | 0 | 0 | 0 | 128 | 64 | 64 | 64 | 0 | 0 | 0 |
P7 | 64 | 19F1 | 128 | 128 | 64 | 0 | 0 | 0 | 512 | 512 | 0 | 0 | 0 | 0 |
P7 | 512 | 41F1 | 64 | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
P7 | 64** | 01F1** | 64 | 64 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
** double birth; *** triple birth; NC: not collected. |
It was found that 47,3% (27/57) (95% CI: 39.7% − 56.9%) of the offspring became infected through horizontal transmission, excluding all positive animals in the first month, as it is not possible to assess with certainty whether the antibody is colostral or from a transplacental infection. About the period of infection, it was determined that most infections occurred up to six months of age (p < 0.00001).
During the experimental period, there was variation in the positivity of the goats, such that positive animals remained positive for short periods. In many cases, the same animal was positive and then negative during the first year of life (Table 1). It was seen that 68.4% (39/57) (95% CI: 53.3% − 79.3%) of the animals evaluated had detectable antibody titers for only up to four consecutive months, and then they became negative. In addition, 73% (14/19) (95% CI: 48.8% − 90.9%) of the animals that had antibodies for more than four consecutive months were positive from the first month of life onwards.
Among the mothers that were positive during pregnancy, 35.5% (11/31) (95% CI: 19.2% − 54.6%) had twin births and 6.5% (2/31) (95% CI: 0.79% − 21.4%) had triple births. It was observed that even among the positive mothers that had double and triple births, at least one of their offspring was negative in the first month of life. Out of the 22 goats born from twin births, 31,8% were negative in the first month. Out of the six kids that were born from triple deliveries, only one (15.1%) had anti-T. gondii antibodies in the first month, and this animal (24F3) remained positive throughout the experimental period.
Regarding management, it was observed that the animals did not receive vaccination. Wild animals were present on all the farms, and on 42.8% (3/7) domestic cats that were in direct contact either with the herd or with the pasture were present. On four farms (P1, P2, P6 and P7), the animals received supplementation with corn-soy protein-energy concentrate (0.5% of live weight), in the late afternoons. The other farms (P3, P4 and P5) did not receive any protein-energy supplementation. Management practices such as navel disinfection, quarantining of newly acquired animals, proper disposal of carcasses and a place for an infirmary were not practiced on any of the farms evaluated. All the herds had the purpose of subsistence, without veterinary assistance, and the animals were being reared for their meat. Goat herding was the main activity of these farms
Comparison performed using multiple logistic regression, of infected animals on the farms between the categories of the variables analyzed (presence of cats, type of water supplied, type of enclosure, sanitary management and presence of sewage on the farm) showed that there were no statistically significant differences regarding these variables (p > 0.05).