TABLE 2.
Parasitemia and heat-sensitive trypanolytic activity in Cape buffalo and bovine sera
| Host | Day of infection with T. brucei A4 + T. congolense 1180 | Dark ground buffy coat parasite scorea | Lowest vol (%) of serum at which trypanolytic activityb was detected on:
|
||
|---|---|---|---|---|---|
| T. brucei A4 | T. congolense 1180 | Other T. brucei and T. congolense strainsc | |||
| Cape buffalo 7810, 7813, and 7752 | 0 | 0, 0, 0 | −, −, − | −, −, − | −, −, − |
| 7 | 1, 2, 2 | −, −, − | −, −, − | ND | |
| 8 | 4, 3, 3 | −, −, − | −, −, − | ND | |
| 9 | 4, 3, 3 | 50, 50, 1.56 | 50, −, 25 | ND | |
| 11 | 0, 0, 0 | 12.5, 1.56, 1.56 | 50, 50, 25 | −, −, − | |
| 14 | 0, 0, 0 | 12.5, 1.56, 1.56 | 12.5, 3.13, 25 | −, −, − | |
| 18 | 0, 0, 1 | 6.25, 1.56, 1.56 | 6.25, 6.25, 1.56 | −, −, − | |
| 31 | 0, 0, 0 | 25, 50, 50 | −, 50, − | ND | |
| Cattle (N’dama 146 and Boran 174) | 0 | 0, 0 | −, − | −, − | −, − |
| 4 | 1, 2 | −, − | −, − | ND | |
| 7 | 0, 0 | 12.5, 25 | −, − | ND | |
| 11 | 5, 5 | 6.25, 1.56 | 12.5, 12.5 | ND | |
| 12 | 4, 3 | 3.13, 1.56 | 25, 25 | ND | |
| 14 | 1, 0 | 1.56, 1.56 | 3.13, 1.56 | −, − | |
| 16 | 0, 0 | ND | ND | ND | |
| 17 | 5, 0 | ND | ND | ND | |
| 18 | 5, 5 | ND | ND | ND | |
a
1, about 5 × 102 parasites/ml; 6, about 106 parasites/ml (27).
b
Buffalo and bovine sera were diluted in PBS-G–10% dialyzed fetal bovine serum; 2 × 104 trypanosomes were added per 100 μl of diluted serum and incubated for 2 h at 37°C, and lysed trypanosomes were evaluated. Results are recorded as the lowest percentage of serum that lysed all trypanosomes in the well. Heating of sera at 56°C for 30 min destroyed the trypanolytic activity. −, no trypanolytic activity observed; ND, not done.
c
T. brucei GUTat 3, T. congolense 300, T. congolense 2642, and T. congolense 3338.