A diseased guinea pig can cause pneumonia

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Pneumonia from a diseased guinea pig

Published on
September 18, 2017

The New England Journal of Medicine has published the article on three Dutch patients who incurred a serious respiratory infection following contact with diseased guinea pigs. A combined study carried out by vets, doctors and microbiologists revealed the cause as the bacterium Chlamydia caviae. This bacterium had been known as the cause of mild eye infection in guinea pigs, but pneumonia in humans had not been documented to date. The article will now alert doctors around the world, enabling them to identify infections earlier and prompting them to make more information on the incidence of C. caviae available.

Publication of the study

Over the past four years at least three people in the Netherlands have incurred a serious to extremely serious respiratory infection from a diseased guinea pig. These three cases were published in the US-based journal New England Journal of Medicine (NEJM) on 7 September. The patients described were healthy and in their thirties. Two of the patients were admitted to Intensive Care Units as a result of the severity of the infection. All of the three patients recovered after being administered the appropriate antibiotic. Marloes Heijne and Hendrik Jan Roest of Wageningen Bioveterinary Research (WBVR) contributed to the study. There was active collaboration with intensivist Bart Ramakers of Bernhoven Hospital, clinical molecular biologist Mirjam Hermans of Jeroen Bosch Hospital and medical microbiologists Peter Schneeberger (JBZ/Bernhoven) and Edou Heddema (Zuyderland MC).

Infection by guinea pigs

Once Chlamydia caviae had been established as the pathogen that caused the pneumonia in the affected patients, WBVR was also able to show C. caviae in a diseased guinea pig by means of source tracing by the Netherlands Food and Consumer Product Safety Authority (NVWA). With assistance from Ghent University, it proved possible to cultivate the bacterium for further molecular research. The genetic characteristics of the strain from the guinea pig turned out to correspond to the DNA of the strain in one patient. This was a clear indication that this patient had in fact been infected by her guinea pigs.

Effects of the bacterium

In guinea pigs C. caviae is known as a pathogen that causes a mild eye infection, and in more serious cases respiratory infections and abortion as well. In humans C. caviae has been linked to eye infections, although respiratory infections had not previously been documented.

Doctors all over the world alerted

It is not yet clear how frequently C. caviae causes respiratory infections. The NEJM article has now alerted doctors all over the world to the fact that C. caviae may cause serious respiratory infections in humans. This will definitely contribute to more rapid diagnosis and greater knowledge on the scope of this problem.