PLAGUE

PLAGUE

• The GREAT DEATH/ MAHAMARI
•  Epidemics of plague, such as the ‘Black Death’, have attacked humans since ancient times, with a high fatality rate. 
• The causative organism, Yersinia pestis, is a small Gram-negative bacillus that is spread between rodents by their fleas, which may also bite humans.
• In the late stages of human plague, Y. pestis may be expectorated and spread between humans by droplets. The incubation period is 3–6 days, and three distinct forms are recognised. 
• Bubonic plague:- In this, the most common form of the disease, the onset is usually sudden with a rigor, high fever, dry skin and severe headache. Soon, aching and swelling at the site of the affected lymph nodes begin. The groin is the most common site of the ‘bubo’ (the swollen lymph nodes and surrounding tissue). A rapid pulse, hypotension, mental confusion and splenomegaly develop rapidly. 
• Septicaemic plague:- The patient is toxic and may have GI symptoms such as nausea, vomiting, abdominal pain and diarrhoea. DIC may occur, manifested by bleeding from various orifices or puncture sites, along with ecchymoses. Hypotension, shock, renal failure and ARDS may lead to further deterioration. Meningitis, pneumonia and expectoration of bloodstained sputum may complicate the picture. There is a high mortality. 
• Pneumonic plague: The onset is very sudden with cough and dyspnoea. The patient soon expectorates copious blood-stained, frothy, highly infective sputum, becomes cyanosed and dies. 
• X-rays of the lung show a lobar opacity.
•  Investigations • A high index of clinical suspicion is required. • An aspirate from a bubo, sputum or the buffy coat (leucocyte fraction) of blood is used to show the characteristic bipolar staining organisms by staining with methylene blue or by immunofluorescence. • Blood, sputum and aspirate should be cultured. • DNA diagnosis through PCR and rapid diagnostic tests (RDTs) has been developed to improve on the sensitivity of the existing methods. • Plague is a notifiable disease.
• Management • Streptomycin or gentamicin is the drug of choice. • Tetracycline and chloramphenicol are alternatives. • Treatment may also be needed for acute circulatory failure, DIC and hypoxia. • Those treating the patient should wear protective clothing, and inadvertent exposure should prompt prophylactic treatment with doxycycline.