PLAGUE; A MEDIEVAL KILLER IN THE PRESENT WORLD: A REVIEW
Authors: Abdul Bari and Ali Abbas Qazilbash
Number of views: 241
Plague as a disease was known in the sixth century, but it was not till the fourteenth century that it became pandemic resulting in the over 14 million deaths in Europe between 1348 and 1400. Unlike smallpox, plague can never be eradicated, as is evident from the recent outbreak of the disease in India. Plague is a disease of the earth, of creatures that run and burrow and of the fleas that live on them. It is found mainly in the wild, often far from man. Plague bacterium need not attack man in order to persist, for it finds all that it needs in wild places. In India, between 1898 and 1919 there may have been more than ten million deaths due to plague. According to WHO between 1961 and 1970 a total of 26,262 cases and 1,887 deaths have been reported worldwide and from 1971-80 there were 16,480 cases and 932 deaths due to plague. During the recent outbreak of plague in India an estimated 55 individuals died of the disease. The plague pathogen is known as Yersinia pestis and its host is black rat, its vector being the flea Xenopsylla cheopis which lives on the rat. Plague is perpetuated by 3 cycles, (1) natural foci among commensal rodents with transmission by fleas (wild plague), (2) urban rat plague, which is transmitted by the rat flea (domestic plague), and (3) human plague, which may be acquired by contact with either of the former cycles and which may be transmitted by pneumonic spread, or, rarely by the bite of a human flea. Plague is now recognized as a well marked disease caused by a Gram-negative facultative anaerobic bacterium. It comes in three forms, all of which are fatal if not properly treated, a) bubonic plague, producing bubos/swellings of the lymph glands, b) pneumonic plague, attacking primarily the lungs: and c) septicemic plague, killing the patient rapidly by poisoning the blood. In bubonic plague the incubation period is 2-8 days. If left untreated the infection spreads to other parts of the body through the blood stream eventually infecting the lungs, leading to pneumonic plague. This type is highly contagious as the patient’s sputum contains the bacillus and droplets of the sputum can spread the disease from person to person, resulting inlocalized outbreaks, or devastating epidemics. Incubation period is 4-6 days after exposure and the patient experiences fever, headache, vomiting and a marked clouding of consciousness. Pneumonic plague is the most fatal, as well as the most directly infectious from of the disease. Treatment of plague involves a variety of antibiotics, namely streptomycin, tetracycline, chloramphenicol and sulfonamides-dosages also vary. A vaccine has also been developed using the killed or attenuated pathogen, but is useless in rapidly developing localized outbreaks such as the recent outbreak in India. Control measured are the key methods for curbing the outbreaks of plague and they include those required during an outbreak to bring it to an end and long term action to prevent the spread of infection from the wild to human population.