Infectious Coryza: Causes, Symptoms, and Treatment
TL;DR: Infectious coryza is caused by Avibacterium paragallinarum bacteria and is identified by foul-smelling nasal discharge plus facial swelling — unlike CRD, which produces no smell. Treat with Premoxil (10g per gallon) daily for 5-7 days, then Vitmin Pro for Day 8-10; severe swelling can call for Ambroxitil, which adds a mucolytic. Isolate sick birds fast — coryza spreads quickly.
What Is Infectious Coryza?
Coryza is caused by the Avibacterium paragallinarum bacteria. It’s known for its foul-smelling nasal discharge — if you can smell the bird’s nasal discharge, it’s most likely coryza. Coryza spreads quickly: once one bird is infected, you need to act immediately to prevent it from affecting the entire flock.
What Are the Symptoms of Infectious Coryza?
Foul-smelling nasal discharge is the key identifier for coryza — you will definitely notice the smell.
- Foul-smelling nasal discharge — this is the key identifier, you will definitely notice the smell
- Swollen face and/or wattles (one side or both)
- Sneezing, difficulty breathing
- Watery eyes
- Decreased egg production
- Loss of appetite
How to differentiate from CRD and coccidiosis: CRD does not produce a foul smell. If there is foul-smelling nasal discharge and facial swelling, it’s coryza — not CRD. If instead you’re seeing bloody droppings with no respiratory signs at all, that points to coccidiosis instead.
How Do You Treat Infectious Coryza With Premoxil?
Treat coryza with Premoxil daily for 5-7 days, then move to a 3-day recovery phase. This amount is given per gallon of water, not scaled to a specific bird weight — this guide doesn’t state a weight basis, so follow the product label if you’re dosing a bird noticeably lighter or heavier than a gamefowl.
| Day | Medication |
|---|---|
| Day 1–7 | Premoxil — 10g (2 sachets) per gallon of water. Replace with a fresh mix daily. |
Recovery Phase
| Day | Medication |
|---|---|
| Day 8–10 | Vitmin Pro — 10g (2 tsp) per gallon of water, daily |
What If Facial Swelling Is Severe?
If facial swelling is very severe, plain Premoxil may not be enough — you can use Ambroxitil (Amoxicillin + Tylosin + Bromhexine) instead, at the same dosage pattern as Premoxil. It includes an additional mucolytic agent that helps clear mucus from the respiratory passages.
How Do You Prevent Infectious Coryza?
Isolating sick birds immediately is the single most important step — coryza spreads rapidly once it takes hold.
- Isolate sick birds immediately — do not wait, coryza spreads rapidly
- Disinfect waterers and feeders regularly
- Ensure good ventilation in the coop
- Quarantine newly arrived birds before introducing them to the flock
What Are the Golden Rules for Treating Infectious Coryza?
- Plain Premoxil may not be enough for severe facial swelling. Switch to Ambroxitil (Amoxicillin + Tylosin + Bromhexine) at the same dosage pattern — the added mucolytic helps clear mucus from the respiratory passages.
- Do not mix medication with Vitmin Pro on the same day during treatment. Give Vitmin Pro only during the recovery phase (after the treatment protocol).
- Always use freshly prepared medicated water each day. Do not reuse yesterday’s mix.
- Remove all other water sources during treatment to ensure the birds drink the medicated water.
- Isolate sick birds immediately from the healthy flock — do not wait.
- Complete the entire treatment course even if the bird looks fine by Day 2. Stopping early risks creating drug-resistant bacteria.
- Prevention is better than treatment. Keep the coop clean, sand dry, deworm regularly, and vaccinate properly.
Disclaimer: This guide is for reference purposes and is based on manufacturer product labels and published poultry health sources. Consult a veterinarian for severe or unusual cases. Observe the proper withdrawal period before consuming meat or eggs from treated birds.
Frequently Asked Questions
What causes infectious coryza?
Infectious coryza is caused by Avibacterium paragallinarum bacteria. It spreads quickly, so once one bird is infected you need to act immediately to protect the rest of the flock.
What is the telltale sign of coryza?
Foul-smelling nasal discharge is the key identifier — you will definitely notice the smell. Swollen face or wattles, sneezing, watery eyes, and decreased egg production often come with it.
How is coryza different from CRD?
CRD does not produce a foul smell. If there is foul-smelling nasal discharge along with facial swelling, it is coryza, not CRD.
How do you treat infectious coryza?
Premoxil — 10g (2 sachets) per gallon of water, daily for 5-7 days with a fresh mix each day — then Vitmin Pro for the recovery phase on Day 8-10.
What if facial swelling is severe?
For heavy face swelling, Ambroxitil (Amoxicillin + Tylosin + Bromhexine) can be used instead, at the same dosage pattern as Premoxil. The added Bromhexine is a mucolytic that helps clear mucus from the respiratory passages.
How fast does coryza spread through a flock?
Coryza spreads quickly — once one bird shows signs, isolate it immediately rather than waiting, since delay lets it move through the rest of the flock.
How can you prevent infectious coryza?
Isolate sick birds immediately, disinfect waterers and feeders regularly, keep good coop ventilation, and quarantine newly arrived birds before mixing them with the flock.