Pneumonia of unknown origin

The World Health Organization is monitoring pneumonia from an unknown cause in Argentina that has so far included three deaths. 

Associated with a single private clinic in the city of San Miguel de Tucuman, located in the northwestern part of the country.

Symptoms include fever, muscle and abdominal pain, and shortness of breath. 

Several patients had pneumonia in both lungs. PAHO said tests for known respiratory viruses and other viral, bacterial and fungal agents were negative.

Biological samples have been sent to Argentina's National Administration of Laboratories and

Health Institute for additional testing, which will include an analysis for the presence of toxic substances.