# Dairy farms in California may transmit H5N1 virus through multiple sources

> A PLOS Biology study found H5N1 in air, wastewater and milk samples from fourteen California dairy farms sampled between October 2024 and January 2025. Researchers also found many infected cows showed no clinical signs. The study suggests transmission occurs through multiple previously unknown routes beyond milking equipment.

- Date: 2026-05-05 · published 2026-05-05T12:00:00.000Z
- Category: disease · region US · magnitude low
- Page: https://feedsoft.ai/events/15913-dairy-farms-in-california-may-transmit-h5n1-virus-through-multiple-sources
- Commodities: [Milk (Class III)](https://feedsoft.ai/c/MILK.md)

## Why it matters

Broader spread routes could prolong dairy herd infections and affect milk output in California. The research does not indicate a sharp change in milk prices.

## Read by commodity

- MILK: neutral

## Similar past events

| Commodity | Date | Event | 5-day % | 20-day % |
| --- | --- | --- | --- | --- |
| MILK | 2024-10-31 | [HPAI in California is a mixed bag for markets](https://feedsoft.ai/events/4684-hpai-in-california-is-a-mixed-bag-for-markets.md) | -1.6% | -2.0% |
| MILK | 2026-03-20 | [Why We Must Vaccinate US Dairy Cattle Against HPAI H5N1 \| The Journal of Infectious Diseases \| Oxford Academic](https://feedsoft.ai/events/15928-why-we-must-vaccinate-us-dairy-cattle-against-hpai-h5n1-the-journal-of.md) | +0.1% | +4.5% |
| MILK | 2025-07-23 | [Current Situation: Bird Flu in Dairy Cows \| Bird Flu \| CDC](https://feedsoft.ai/events/15983-current-situation-bird-flu-in-dairy-cows-bird-flu-cdc.md) | -0.6% | +0.1% |
| MILK | 2024-07-10 | [Bird flu response in Michigan sparks COVID-era worry on farms \| Reuters](https://feedsoft.ai/events/29269-bird-flu-response-in-michigan-sparks-covid-era-worry-on-farms-reuters.md) | -0.1% | +2.6% |
| MILK | 2024-04-03 | [Bird flu hits Texas dairy cows, hens, human as ducks migrate](https://feedsoft.ai/events/16103-bird-flu-hits-texas-dairy-cows-hens-human-as-ducks-migrate.md) | -4.7% | -5.0% |

## Sources

- phys.org: https://phys.org/news/2026-05-dairy-farms-california-transmit-h5n1.html

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Data from Feedsoft AI (https://feedsoft.ai/). For information only; not investment advice.