Perhaps the danger it represents for human health is relative but its repercussions on the agri-food sector are proving to be particularly devastating. Let's talk about bird flu, the consequences of which are making themselves felt in Japan, more than anywhere else in the world. Result: 17 million domestic poultry chickens were culled throughout the Asian country, equal to about 9% of laying hens. At the same time, the price of eggs has skyrocketed. According to data from the national cooperative JA.Z-Tamago, in early April in Tokyo the wholesale price for a kilogram of medium-sized eggs was 350 yen (2.40 euros), the highest since 1993, and 65% more than a year ago.

Citing data from a local retailer, the BBC puts the price increase at 70%. Kewpie, a well-known mayonnaise manufacturer, estimates a 21% increase starting this month. Japanese-style poached eggs, which were previously offered free to customers with sukiyaki hot pot orders, now cost 55 yen each. The prospect is a drop in the net profit of the entire product to around 47%.

A big problem for a country that features eggs among the winning ingredients of its cuisine. Last month McDonald's Japan had to announce the possible suspension of its famous Teritama hamburgers during peak periods (the name Teritama is derived from the crasis between teriyaki, a well-known sauce, and tamago, which means "eggs").

In general, most restaurants have had to change their menus, making sandwiches, salads and other dishes completely egg-free. About 28% of listed restaurant companies in Japan have suspended or may consider suspending parts of their menus, according to a study this week of 100 such restaurants by research firm Teikoku Databank.

The general scenario seems destined to worsen, given that in Japan, the avian epidemic continues not to loosen its grip at all. The Japanese case is however the extreme tip of a phenomenon that is manifesting itself on a global level.