Volume 31, Number 6—June 2025
Dispatch
Oral Flea Preventive to Control Rickettsia typhi–Infected Fleas on Reservoir Opossums, Galveston, Texas, USA, 2023–2024
Lucas S. Blanton
and Alejandro Villasante-Tezanos
and Alejandro Villasante-Tezanos
Table 1
Summary of fleas collected from opossums in a study of use of oral flea preventive to control Rickettsia typhi–infected fleas on reservoir opossums, Galveston, Texas, USA, 2023–2024*
| Opossum no. | Group | Total no. fleas | No. live fleas | No. dead fleas | Proportion dead fleas |
|---|---|---|---|---|---|
| 1 | Experimental | 87 | 7 | 80 | 0.920 |
| 3 | Experimental | 8 | 0 | 8 | 1 |
| 5 | Experimental | 715 | 1 | 714 | 0.999 |
| 6 | Experimental | 595 | 3 | 592 | 0.995 |
| 8 | Experimental | 247 | 2 | 245 | 0.992 |
| 2 | Control | 5 | 5 | 0 | 0 |
| 4 | Control | 54 | 54 | 0 | 0 |
| 7 | Control | 89 | 89 | 0 | 0 |
| 9 |
Control |
247 |
247 |
0 |
0 |
| Total | 2,047 | 408 | 1,639 |
*Opossums in the experimental group were captured by using traps baited with canned cat food mixed with a crushed 270-mg spinosad flea control tablet (Elanco, https://farmanimal.elanco.com); opossums in the control group were trapped in the same manner but did not receive spinosad. For both groups, opossums were sedated and combed for fleas, which we determined to be alive (moving) or dead (no movement).
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