Efforts to increase food production in Africa may be increasing the risk of plague infection.Plague has been killing people for hundreds of years.A new report looks at efforts to clear land for farming in natural,undeveloped areas of Tanzania.The report links the development of natural lands into croplands to a sharp increase in the number of rats.It warns the animals often carry insects infected with plague.
Many people become frightened when they hear the word"plague."One of the most famous periods of plague death was known as the"Black Death."It was a time 700 years ago when the disease killed more than 25 million people in Europe.
Health officials do not believe plague will kill many people in Africa.But they are worried about the rising number of plague infections.Thirty to 60 percent of those infected will die if they are not given medicine.
Plague is caused by bacterium.It is passed between animals and humans through the bite of an inflected flea or by touching an infected animal.Rats often carry fleas.The insects feed on the blood of an infected rat.
There are three forms of plague.The most common is bubonic plague.This was the disease that spread in Europe during the 14th century.Bubonic plague causes enlargement of lymph nodes.The lymphatic system is the part of the body's natural defense system against disease.
If the plague infection is not treated,the bacteria can reach the lungs.Then,the person may develop pneumonic plague.This is the least common but most aggressive form of the disease.It can be easily spread through small droplets expelled from the person's nose or mouth.A person infected with bubonic plague cannot infect others.
The World Health Organization says pneumonic plague is one of the most deadly infectious diseases.People suffer high body temperature,shaking,pain,weakness,and muscle and joint pain within two to three days of being infected.
Antibiotic drugs can cure the disease.But the infected individual must take them very quickly,because pneumonic plague can kill people within 24 hours after infection.The WHO says only a small number of reported cases are of the pneumonic form.
Kristofer Helgen is with the Smithsonian Institution's Museum of Natural History in Washington,D.C.He helped to write the new report.It was published online in the American Journal of Tropical Medicine and Hygiene.He spoke to VOA about the disease.
"It maybe surprises people to learn that plague remains a public health concern in various parts of the world--especially in Africa south of the Sahara.Plague circulates in small mammals and rodents.And when the conditions are right,it's a disease that can spread to people and it can still be a deadly disease.Now,plague is a disease that is treatable with antibiotics.And in that regard,it's considerably maybe less scary,less alarming than other emerging diseases like Ebola.But we should remember that this is a disease that is still on the ground in Africa and remains a public health concern."