Black Death Here Again?

Breaking News

In Egypt:

The Egyptian  government has closed its country’s border with neighbouring Libya, following of a recent outbreak of the bubonic plague, commonly known in medieval times as the Black Death, in a coastal village 30 kilometres away from Tubruq, Eastern Libya.

The Egyptian Health Minister, Dr. Hatim Al Jabali, said that strict regulations have been put in place at all entry points from Libya to Egypt. He also insisted that there are no cases of bubonic plague on Egypt’s side of the border with Libya.

At the WHO

A team of experts from the World Health Organisation (WHO) is on its way to the Libyan-Egyptian border to investigate the outbreak.

According to an official from the World Health Organisation (WHO), John Jabbour, a Cairo-based diseases specialist, the Libyan authorities have reported an outbreak of bubonic plague in the Mediterranean coastal town of Tubruq, and that WHO was sending a team to investigate. Dr Jabbour added that WHO still didn’t have “a full picture” of the situation. (see link here.)

He said preliminary information from Libyan authorities showed 16 to 18 reported cases including one death, and that Tripoli had asked for assistance from WHO.

If true, these cases would be the first of the disease in Libya in 25 years.

In Libya

About 20 people have been infected with the disease. Libyan media have spoken of between one and three fatalities, though the Libyan Health Minister has said that there was no reported deaths. (see link here.)

‘Thirteen cases of the plague have been recorded Eleven people have already (been treated and) left hospital,’ he said, without reporting any deaths.

‘The situation is under control. We are leading a massive campaign to clean up and disinfect the place,’ said Mr Mohamad Hijazi, explaining that the illness was caused by rising rat numbers attracted by livestock being reared near homes.

He said cowsheds had been destroyed and a foreign pest control firm sent to eradicate the rats, in an operation to be supervised by a World Health Organisation (WHO) representative and a French expert.

Mr Mohamad Hijazi said the illness had previously hit Libya in the 1970s and 1980s.

Recent Cases

1. Epidemiology.

According to WHO’s document there are between 1000-2000 cases  reported each year. In fact, in 2003 nine countries reported 2118 cases of plague and 182 deaths from plague. These reports were from regions with endemic areas of plague, e.g. sub-tropics and the tropics, and more than 95% of these cases and deaths were reported from Africa.

There have been recent outbreaks of plague in India in 2002 and Algeria in 2003.

Outbreaks of Yersinia pestis occur whenever there is a loss of the normal host for the fleas e.g. if the rat population are affected by another illness increasing their mortality. The fleas then find another host to feed on e.g. human

2. In USA

In November 2002, two people from New York City were hospitalised for the bubonic plague. The plague is known to many as “The Black Death“, a pandemic that killed about 200 million people world-wide during the Middle Ages.  As the news broke, the New York City Health Commissioner had to reassure New Yorkers that no plague epidemic was occurring and that the disease would not be spread from person to person. (read more here.)

In August 2008, Health Director, Bil Wineman told the county board of  the  Scotts Bluff County, in western Nebraska, that a local veterinarian had reported a case of bubonic plague in a pet cat from a home south of Gering, which was the county’s first in recent history. (read more here.)

On 19 April 2009, the Associated Press reported about a woman with the bubonic plague, the first in LA since 1984.  She was admitted to a hospital on 13 April with a fever, swollen lymph nodes and other symptoms. A blood test confirmed that she had the bubonic plague; and she was given antibiotics.  A day earlier, the TV show “HOUSE” portrayed a woman who presented mysterious symptoms. It was finally determined to be a case of the plague after it was revealed where she got her dog. (read more  here)

On 4 June 2009, New Mexico’s health officials say an 8-year-old boy from the Santa Fe County has died after contracting bubonic plague and his 10-year-old sister, who also contracted the illness, is hospitalized and recovering.  (read more here.)

Interesting coincidence there, but what are the real chances about getting the plague? Well, according to health officials there are an estimated 10-20 Americans that contract the plague each year. They live in mostly rural communities and therefore aren’t as newsworthy as someone in the big city.

The Centers for Disease Control and Prevention says an average of 10 to 20 persons contract the plague each year in the United States.

3. In Taiwan

Green Island, only a little over 16 nautical miles southeast of Taitung on east Taiwan, is one of the world’s best spots for scuba diving and snorkeling.  The island, which used to be a concentration camp for political prisoners, has amazingly beautiful and thriving coral reefs, which may be destroyed by atramentous necrosis, or black death, in five to six years.

That is a prognosis offered by Taiwan’s leading marine biologist, Chen Jhao-lun, a senior research fellow at the Academia Sinica who conducted research on the threat of black death on the coral reefs around Green Island.

The coral disease is named black death because it typically presents itself as blackened lesions that spread within days across an infected surface of colonies. Could this be a new form of black death other than the one caused by the plague? (see link.)

4. World Distribution of Plague from 1970 to 1998 – see map below:

5. The Black Death in Numbers

From 1346 to 1351, the Black Death struck Europe:

• In less than two years 30% to 60% of the population of Europe was wiped out.
• Nearly 75 million died in western Europe alone.
• 18000 people died in London in the course of three years.
• Almost 1/3 of the worlds population had died from the plague by 1350.
• Estimates of more than 230 million deaths worldwide.
• Mortality rate of the bubonic plague was 30% to 75% percent.
• Within 1-7 days the first symptoms occurred, including fever, nausea, headache and an infection the lymph nodes.

Comparison:

The “Spanish Influenza” of 1918 killed 25 million in one year. Within 7 days, the disease occurred in every state of the U.S.A. and struck France a week later.

Two weeks after that, it struck China and again 2 weeks later it had spread throughout the continent of Africa and Latin America.

About the Plague

Plague is the name given to infection with the bacteria called Yersinia pestis. This bacterium is a Gram negative bacillus and a member of the Enterobacteriaceae family. It is primarily a enzoonotic infection – a disease found in rodents, especially marmots, rats and squirrels and their fleas, in many parts of the world.

Yersinia pestis is easily destroyed by sunlight and drying.  Even so, when released into the air, the bacterium will survive for up to one hour or more; and  it is able to live in contaminated soil for at least 24 days under natural conditions.

Types of Plague

There are four different types of plague. They are:

1. The Bubonic Plague.

2. The Septicemic Plague.

3.  The Pneumonic Plague

4. The  Abortive Plague.

All the four types of plague can turn into a pandemic, but the most prevalent forms are the bubonic plague and the pneumonic plague. However, out of a bubonic plague, a septicemic plague can arise. And if it is not treated, the septicemic pest can lead to a pneumatic plague and thus causing widespread deaths.

The Bubonic Plague is the most common form of plague.  This occurs when an infected flea bites a person or when materials contaminated with the Yersinia pestis enter through a break in a person’s skin.  Patients develop swollen, tender lymph glands (called buboes) and fever, headache, chills, and general weakness. Bubonic plague does not spread from person to person.

Bubonic plague is believed to have been the “Black Death” that killed 75 million people in Europe, and more than 230 million people world-wide  between 1346 and 1351.

The Septicemic Plague occurs when plague bacteria multiply in the blood.  It can be a complication of pneumonic or bubonic plague, or it can occur by itself.  When it occurs alone, it is caused in the same way as the bubonic plague, but buboes do not develop. Patients have fever, chills, prostration, abdominal pain, shock and bleeding in the skin and other organs.  Septicemic plague does not spread from person to person.

The Pneumonic plague occurs when the Yersinia pestis infects the lungs.  This type of plague can spread from person to person, through the air. Transmission can take place if someone breathes in aerosolized bacteria, which could happen in a bioterrorist attack. Pneumonic plague is also spread by breathing in the Yersinia pestis suspended in respiratory droplets from a person (or animal) suffering from the with pneumonic plague.  Becoming infected in this way usually requires direct and close contact with infected person or animal.  Pneumonic plague may also occur if a person with bubonic or septicemic plague is untreated and the bacteria spread to the lungs. This can occur within a few days.

The Abortive Plague is the harmless variant of the pest. It often shows itself with light fever and a little swelling of the lymph nodes.  After getting over  the infection, the body produces specific antibodies which guarantee a long-lasting immunity against all forms of the disease.

Mode of Transmission

• Bite from infected fleas
• Direct contact
• Inhalation
• Ingestion

Human infection most commonly results from being bitten by a flea called Xenopsylla cheopis. These fleas feed off the infected rodents and swallow the bacteria which then multiply in the fleas stomach. This makes the flea hungry and they then bite a human and vomit the bacteria into the bite. The flea dies of subsequent starvation as the bacteria in the stomach inhibits blood flow to the gut making them vomit when they eat.Factors that lead to increased spread of Yersinia pestis include cold temperature, increased humidity and over-crowding.

Presentation

Infection with Yersinia pestis begins with non-specific “flu-like” symptoms:

• Sudden onset chills
• Fever
• Headache
• Diarrhoea
• Muscle ache
• Weakness
• Swelling of lymph nodes
• Nausea and vomiting

These usually follow an incubation period of 3-7 days.

Following this the infection can take on several forms but the three commonest are:

• Bubonic plague – this is the most common and usually follows a bite from a flea. The bacteria pass from the skin to local lymphatics and to local lymph nodes. The infection usually involves lymph nodes of the groin although the axillae and neck may also be effected. The bacteria replicate in the lymph node causing it to become enlarged and swollen and very tender, they are called buboes. Occasionally they may suppurate.

• Septicaemic plague – there is usually no evidence of lymph node involvement. The infection spreads into the blood and septic shock ensues. This may follow either a flea bite or direct contact on to broken skin. Patients may have bleeding from the skin and mucous membranes and haemorrhage into organs due to disseminated intravascular coagulation. They may also develop red tender nodules on the skin with a white centre. There may also be necrosis of blood vessels with purpura and gangrene. Symptoms can appear on the day and patients can die within 24 hours if not promptly treated.

• Pneumonic plague – This is the least common presentation of the three but is the most dangerous. The mortality and contagibility of pneumonic plague is very high. Lung infection can be primary from inhalation of droplets or secondary to advanced infection of the bubonic type. Pneumonic plague can be spread directly between humans and does not require a vector. The infection may present just as any bronchopneumonic illness with chest pain, cough, breathlessness and haemoptysis. Complications include disseminated intravascular coagulation, multi organ failure and acute respiratory distress syndrome. Chest X ray will show consolidation and pneumonic plague can progress rapidly to septicaemia. The incubation period can range from 2 hours to 4 days.

Other types of Yersinia pestis infection classified by WHO include cellulocutaneous plague, meningeal plague, pharyngeal plague, pestis minor and asymptomatic plague:

• Cellulocutaneous plague – this is rare and presents as infection of the skin.
• Meningeal plague – this is seen in children but is uncommon. It presents similar to other cases of meningitis and is thought to arise from incomplete treatment of other types of plague.
• Pharyngeal plague – this follows consumption of Y. pestis e.g. in food or inhalation and presents as tonsillitis with local lymphadenopathy.
• Pestis minor – presents with mild fever and lymphadenopathy and usually settles in a week.
• Other forms of plague described are asymptomatic plague and abortive plague.

Symptoms and Treatment

With pneumonic plague, the first signs of illness are fever, headache, weakness, and rapidly developing pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery sputum. The pneumonia progresses for 2 to 4 days and may cause respiratory failure and shock. Without early treatment, patients may die.

Early treatment of pneumonic plague is essential. To reduce the chance of death, antibiotics must be given within 24 hours of first symptoms. Streptomycin, gentamicin, the tetracyclines, and chloramphenicol are all effective against pneumonic plague.

Antibiotic treatment for 7 days will protect people who have had direct, close contact with infected patients. Wearing a close-fitting surgical mask also protects against infection.

Investigations

Yersinia pestis can be best identified in culture of infected tissues or fluids, for example, blood, sputum or bubo aspirates. Rapid dipstick tests, immunoassays and polymerase chain reaction methods are only available in some states.

Management

The mainstay of treatment is antibiotics. However, there are no trials comparing the efficacy of individual antibiotics. All patients need strict isolation as should close contacts.

Traditionally the following have been used:

• Streptomycin – reduces mortality rate to 4-15% when given parenterally.
• Gentamicin – is considered as a second line parenteral treatment and success rates may be similar to streptomycin.
• Fluoroquinolones – these are as efficacious as aminoglycosides and tetracyclines in experimental induced plague and can be given orally.
• Chloramphenicol – may be better in plague meningitis as it crosses the blood brain barrier, however this has not been confirmed and the drug is associated with toxicity e.g. bone marrow failure.
• Tetracycline (not in children) and doxycycline – these have been used in the treatment and prophylaxis of plague.

Doxycycline or ciprofloxacin are probably first line in pregnant patients. Children can be treated with streptomycin or gentamicin.

Resistance of plague to antibiotics can also occur e.g. tetracycline resistance and quinolone resistance – these reports are very rare.

Prognosis

The untreated mortality of plague is high especially for pneumonic plague where it approaches 95% and septicaemic plague which is fatal without therapy. Untreated bubonic plague has a mortality of 30-75%. With treatment the overall mortality rate is reduced to 4-15%.

Prevention

A vaccination had previously been developed (a formaldehyde-killed whole bacille vaccine) but this did not prevent plague effectively and thus is not recommended in the setting of outbreaks.

The vaccinations are really only used for prophylaxis in high risk groups such as, laboratory staff who will be handling plague infected tissue.

The following preventive measures need to be considered:

• Surveillance of disease and thus awareness of areas where plague is active.
• Precautions against flea bites – good hygiene and sanitation.
• Education of persons likely to be involved in handling carcasses that may be infected with plague to wear appropriate clothing e.g. gloves.
• Use of licensed insecticides to kill fleas in outbreaks of plague.
• Rat control measures.
• Strict isolation of patients who are infected and avoidance of contact with infected patients especially those with pneumonic plague.

Prophylactic antibiotics have also been used in the following groups:

• Persons bitten by fleas during an outbreak.
• Persons exposed to tissues or fluids from animals infected with the plague.
• Persons living in a house where a patient developed bubonic plague.
• Persons in close contact with those suspected of pneumonic plague.

History and Future of Plague

The organism responsible for plague was isolated in 1892 by Alexandre Yersin. The organism was originally named Pasteurella pestis but this was changed to Yersinia pestis in 1962. The discovery of the flea as the vector for plague was made in 1898 by Paul-Louis Simond. Lately, due to archeological findings by experts, it has been said that the disease could have been originated from Egypt.

Plague epidemics have been described for ages, as early as the 11th century B.C., both in China and the Western world.  However, the more infamous occurrence is the Black Death which occurred in the mid-14th century and claimed the lives of more than 230 million persons.

There have been worldwide concerns that plague could be used in biological warfare. The Yersinia pestis infection would be primarily pneumonic plague that is the result of aerosol based mechanisms of release.

Advice to travellers

• Avoid contact with rodents
• Use of insect repellants on skin and clothes
• Hand washing
• If in close contact with suspected or confirmed case – use gloves and face masks
• Seek prompt medical advice if fever develops or lymphadenopathy

Advice for Practitioners during Plague Outbreak.

• High index of suspicion e.g. extra number of patients presenting with pneumonia.
• Use gloves, face masks and gowns if available.
• Notify authorities as soon as possible.
• Initiate antibiotic therapy within 24 hours to reduce mortality.
• Isolate patients – this may mean isolation within the patients own home if other facilities not available. Infected patients may need to be grouped together.
• Sterilise all equipment. If this is not possible equipment needs to be disposed of effectively.

Conclusion

If Singaporeans are not careful, and if we do not take immediate preventive actions when the need arises, this Black Death disease, together with the swine flu, bird flu, dengue fever, malaria, tuberculosis and AIDS can easily find their ways to run havoc in our lives too, if the imported foreigners have not already done so.  And one fine day, with the eagerness and earnestness of some smart millionaire-inspired politicians, Singaporeans will surely become an extinct species!

References:

1. Perry RD, Fetherston JD; Yersinia pestis–etiologic agent of plague. Clin Microbiol Rev. 1997 Jan;10(1):35-66. [abstract]
2. Inglesby TV, Dennis DT, Henderson DA, et al; Plague as a biological weapon: medical and public health management. Working Group on Civilian Biodefense. JAMA. 2000 May 3;283(17):2281-90. [abstract]
3. World Health Organization Plague – factsheet No. 267; Feb 2005.
4. Bossi P, Tegnell A, Baka A, et al; Bichat guidelines for the clinical management of plague and bioterrorism-related plague. Euro Surveill. 2004 Dec 15;9(12):E5-6. [abstract]
5. Calhoun LN, Kwon YM; Salmonella-based plague vaccines for bioterrorism. J Microbiol Immunol Infect. 2006 Apr;39(2):92-7. [abstract]
6. Bioterrorism Readiness Plan: A template for healthcare facilities. APIC Bioterrorism Task Forceand CDC Hospital Infections Program Bioterrorism Working Group, Apr 1999.