Giuseppe Sanarelli

Italian bacteriologist

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 13, 2026

Quick Summary

Giuseppe Sanarelli was an Italian bacteriologist who, in 1896, claimed to have isolated an organism called Bacillus icteroides from yellow fever patients. This claim was investigated by U.S. Army physicians Walter Reed and James Carroll. Their research, published in 1899 and 1900, concluded that Sanarelli's bacillus was not the cause of yellow fever but rather belonged to the hog-cholera bacillus group and acted as a secondary invader. This work was part of a larger effort to understand the transmission of yellow fever, which was eventually proven to be spread by mosquitoes.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Walter Reed
In 1896 an Italian bacteriologist, Giuseppe Sanarelli, claimed that he had isolated from yellow-fever patients an organism he called Bacillus icteroides.
Read More
In 1896 an Italian bacteriologist, Giuseppe Sanarelli, claimed that he had isolated from yellow-fever patients an organism he called Bacillus icteroides.
Read More