Reaction profile
The FDA adverse-event record for lack of efficacy (endoparasite) - ostertagia/teladorsagia
28 FDA reports name lack of efficacy (endoparasite) - ostertagia/teladorsagia, a lower-volume reaction in the CVM extract (VeDDRA 2799). Plate stamps and neighbourhood peers follow.
- #2027 of 2,481
- by report volume (all reactions)
- 28
- reports citing this reaction
- 17.9%
- death-coded share
- Cattle
- most-affected species
Release-over-release change
What changed in the latest FDA data snapshot
PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Lack of efficacy (endoparasite) - Ostertagia/Teladorsagia has 28 reports now versus 26 in that prior snapshot: 2 more (7.7%).
- Report change
- +2
- Death-coded reports
- +0
- Death-coded share
- −1.4 pts
This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.
Subscribe to Lack of efficacy (endoparasite) - Ostertagia/Teladorsagia changesFDA AER · VeDDRA plate
Code 2799 VOL-TRACE
VOL-TRACE · DEATH-ELEV · LOWER-Q · PHOTO-FINISH · SPECIES-CATTLE · DRUG-LEAD · DESK-WIDE · BOOK-FULL
- VOL-TRACE 28 reports
- DEATH-ELEV 17.9%
- LOWER-Q #2027/2481
- PHOTO-FINISH Absence seizure
- SPECIES-CATTLE Cattle · 25
- DRUG-LEAD Eprinomectin · 16
- DESK-WIDE 10 breeds
- BOOK-FULL 8/8 fields
Nearest volume peer: Absence seizure (±0 reports)
Instrument codes from this reaction’s FDA CVM adverse-event extract: volume band, death-coded share, corpus rank, photo-finish peer, lead species, lead drug, breed desk, and book completeness. Not a clinical diagnosis.
Lower-volume neighbourhood around Lack of efficacy - Ostertagia/Teladorsagia
Lower-third volume poles plus nearest peers, not a full reaction corpus board reprint.
What the FDA AER plate says about Lack of efficacy (endoparasite) - Ostertagia/Teladorsagia
Signature read: 28 reports place Lack of efficacy (endoparasite) - Ostertagia/Teladorsagia in the lower third of FDA AER volume (#2027 of 2,481). Report volume is lower-third scale: 28 named reports in the openFDA extract. 5 of 28 reports were death-coded (17.9% of named reports, not a population mortality rate). Nearest volume peer: Absence seizure (±0 reports). Lead species Cattle (25). Lead co-reported drug Eprinomectin (16).
Read these counts as reporting volume, not risk: per our methodology, Lead co-reported drug Eprinomectin appears in filings alongside this reaction; that is association, not causation. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.
Species Most Affected
Breeds Most Affected
Associated Drugs
What to do with this reaction
- Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
- Browse the full reaction directory to compare report counts across reaction types. All reactions
A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.
Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025
Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →