Experiments on the Transmission of an Icterogenic Agent in Yellow Fever Vaccine to Horses and Swine.

The study focuses on the transmission of a hepatitis-causing agent found in yellow fever vaccines into horses and swine, in order to understand the spread of jaundice in humans after vaccination.

Background of Hepatitis Transmission Research

• The medical research conducted investigates the cause behind the repeated incidences of jaundice, that manifested in various degrees of severity, after yellow fever vaccination. This was observed especially among the military personnel during World War II.
• Similar instances of post-vaccination jaundice were reported in other countries like England and Brazil. The jaundice was seen as a probable fallout of hepatitis attacking the liver parenchyma, instead of an inflammation-induced obstruction in the bile ducts or swollen duodenal mucosa.
• Few other investigators had uncovered the existence of a jaundice-causing agent present in certain human sera, and its spread among humans through serum injections.

Objective of Current Research

• The challenge was that this phenomenon of jaundice couldn’t be experimentally induced in animals so far. Hence, researchers aimed to identify an animal model that could replicate human-like symptoms of jaundice following yellow fever vaccination.
• With a focus on this, the researchers conducted experiments to mimic this condition in swine and horses.

Choice of Experimental Animals

• Swine were chosen due to past successful experiments by Danish researchers, Andersen and Tulinius, who were able to cause infectious hepatitis in swine by feeding them duodenal juice from humans affected by epidemic jaundice.
• On the other hand, horses were chosen because a form of hepatitis was observed in them following the injection of equine encephalitis virus, thus making them another plausible animal model for this research.