Drug profile

The FDA adverse-event record for Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal

34 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal. See the species affected, top reactions, and outcomes below.

34
adverse-event reports
23.5%
death-coded share
Horse
most-reported species
13
Colic - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
34
Total Reports
8
Deaths Reported
23.5%
Death Rate

Active Ingredients

Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal

Administration Routes

Intramuscular

Species Affected

Horse 32
Donkey 2

Most Affected Breeds

Quarter Horse 7
Warmblood (unspecified) 6
Morgan 3
Horse (unknown) 3
Mustang 2
Miniature 2
Tennessee Walking Horse 2
Donkey (other) 2
Shire 2
National Show Horse 1

Most Reported Reactions

Colic 13
Fever 10
Other abnormal test result NOS 5
Lameness 4
Lack of efficacy - NOS 4
Death 4
Anaemia NOS 4
Tachycardia 3
Injection site swelling 3
Lethargy (see also Central nervous system depression in Neurological) 3
Facial oedema 2
Nasal discharge 2

Outcome Breakdown

Recovered/Normal
16 (47.1%)
Ongoing
6 (17.6%)
Died
6 (17.6%)
Outcome Unknown
4 (11.8%)
Euthanized
2 (5.9%)

Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal Adverse Event Insights

34 reports name Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal; 8 recorded a death outcome (23.5% of reported events, not a population-level mortality rate). Active ingredient: Clostridium Tetani Seed Lot #18 H-1 Massachusetts Strain;Eastern Equine Encephal. Administration route: Intramuscular.

By species: Horse (32 reports), Donkey (2 reports). By breed: Quarter Horse (7), Warmblood (unspecified) (6), Morgan (3).

Leading clinical signs: Colic (13), Fever (10), Other abnormal test result NOS (5), Lameness (4). Outcome, 34 coded reports: Recovered/Normal leads at 47.1%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.