One person have been included to persons earlier placed under observation from Delta State at the Centre for Lassa Fever in Irrua, Edo State.
The new figure was given by the State Commission for Health, Nicholas Azinge.
The individual added to those under observation was a lab technician working with one of the hospitals that admitted the deceased medical doctor.
This addition makes it a total of 41 persons closely monitored by the health authorities.
Eight people have earlier been placed under surveillance in Delta State after being suspected of being in contact with a doctor killed by Lassa Fever.
They are members of staff of the hospital a medical practitioner died of the disease in Delta State.
The new outbreak of Lassa Fever was announced on August 22 by Dr. Azinge.
Sensitisation programmes have been launched by different states to guard against a spread of the deadly disease.
The Nigerian Medical Association has advised the Federal Government to urgently address the challenges in the primary healthcare system by declaring a state of emergency on the health sector.
Addressing a news conference in Abuja on Sunday ahead of the 2015 Physicians’ week, the President of the Association, Dr. Kayode Obembe, said the Federal Government needed to tackle cases of measles and other vaccines’ preventable diseases just like it addressed and eradicated Polio.
Dr. Obembe added that since there was no specific treatment for measles, primary prevention of it and other vaccines preventable diseases remained the best option to eradicate all such diseases which have claimed the lives of many children in Nigeria.