Detecting avian influenza spill-over to dairy cattle by bulk milk testing in Switzerland — What can we learn from the current outbreak in the US?

This project was a runner-up for the  "Novel research (qualitative)" prize on our Pandemics (Sept 2024) course. The text below is an excerpt from the final project.

In the beginning of 2024, H5N1 suddenly extended its host reservoir to dairy cattle and caught the US by surprise. This article is motivated by preventing H5N1 becoming zoonotic through controlling its host expansion to dairy cattle. Research resulting from the ongoing bovine H5N1 outbreak in the US should inform preparations in other parts of the world. Concretely, this research article is about the identification of affected dairy cattle herds in Switzerland through bulk milk testing. A threat model of a commencing bovine H5N1 outbreak caused by a single spill-over event in Switzerland is at the base of this article. Detection of a single infected cow in a bulk milk pool on either farm level or dairy processing plant level appear feasible using PCR based assays. Since Switzerland has already active cattle surveillance in place, including regular quality control of milk at the farm level, the prerequisites for spill-over detection and subsequent contain-
ment are good in Switzerland .

The considerations in this research article are transparent for an audience, which is used to read scientific publications from the natural sciences, but are aimed to be accessible also to an interested amateur. To that end, in the first introductory part, this text presents a synopsis on H5N1 in general, the progression of the US outbreak, different detection methods and current testing strategies and prerequisites in the US and Switzerland. In the second part, this article puts this information into context, presents rough calculations on detectability of H5N1 and what this means for implementation in Switzerland. Finally, this text recommends to latch onto the existing milk testing infrastructure in Switzerland and discusses limitations and implications of such a strategy.

Full project

You can view the full project here.