Pneumonic plague outbreak in Congo sparks WHO response

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Feb 18, 2005 (CIDRAP News) – An unusual outbreak of pneumonic plague that has killed at least 61 people and potentially sickened hundreds of others is the focus of a World Health Organization (WHO) mission in a war-torn area of the Democratic Republic of the Congo (DRC).

A multidisciplinary team of 10 people will leave tomorrow for the DRC, according to the transcript of a WHO news teleconference held at WHO headquarters today. The team hopes to go to the politically unstable region to support efforts to find, quarantine, and treat ill and exposed workers at the Zobia diamond mine, many of whom have fled the area.

Plague is endemic in the northeastern province of Orientale, near Uganda, but this outbreak is unusual because it appears to be exclusively the pneumonic form of plague, which accounts for only 2% of reported plague cases overall, said Dr. May Chu of the WHO's Alert and Response Operations program. The pneumonic form can spread from person to person via aerosolized bacteria, bypassing the usual route of flea bites or infective materials, she said.

Pneumonic plague often starts with cough, fever, and discomfort within 2 to 6 days of infection. People develop extreme difficulty breathing as their lungs fill with fluids and can die in as little as 48 hours.

"They usually die, not because of vast disseminated plague as it would be in a normal and bubonic or septicaemic form, they . . . die because of lack of oxygen," Chu said.

Antibiotics can treat the disease and prevent a secondary outbreak. Quarantine and isolation are also essential, she added.

Quarantine will be a challenge because the outbreak occurred in an open diamond mine with about 7,000 miners working under poor sanitary conditions, said Dr. Eric Bertherat of the WHO Alert and Response Operations program, who is leading the WHO response team. Although the epidemiologic data are incomplete, the outbreak may involve hundreds of cases, he said.

Panic, which has accompanied outbreaks of plague for hundreds of years, may foster the spread of the disease. "Maybe two-thirds of the population ran away from the mine," traveling as far as 200 kilometers, Bertherat said.

Providing it can enter the region, he said, the WHO team will work with local staff of the Ministry of Health and workers from the nongovernmental organizations Medecins Sans Frontieres and MedAir to ensure appropriate case management in the mine and the affected villages of Buta and Titula, as well as to trace contacts of infected people.

The scope of their task remains hazy. Sixty-one deaths have been recorded in health facilities, he said. Many miners died as they fled the area, falling in the forest or along trails. The medical staff on the ground collected health facility data that fit the definition of pneumonic plague and found 300 to 400 suspected cases.

"It is difficult to be sure that really all of them are a case of pneumonic plague," Bertherat said, and later added, "What we know is that new cases are still occurring in the mine and that yesterday, there [were] 20 cases admitted in the health facilities in Zobia, close to the mine."

Preliminary results from rapid diagnostic tests confirmed pneumonic plague. Forty samples have been taken for culture and serology tests at the Institut de la Recherche Biomedicale in Kinshasa, WHO said.

Political and economic conditions will complicate the WHO mission. The troubled Ituri region has been "most affected by very chronic and dramatic humanitarian crisis" since 1998, including armed conflict, said Dr. Giuseppe Annunziata, with the Department of Health Action in Crisis, at the teleconference.

"Humanitarian access to this area is very difficult," Annunziata said. "To provide any kind of epidemiological investigation or outbreak response is very problematic."

Bertherat said working conditions heightened the problem. "It's very unusual to have so many people being and working together in [such a] crowded place and in the middle of a highly endemic area for plague," he said.

The Zobia mine had been closed, but it reopened Dec 16, 2004, attracting an influx of miners from throughout the province, he said. The first case of pneumonic plague was diagnosed Dec 20, 2004.

News of the Congo outbreak prompted infectious disease expert C. J. Peters, MD, to compare it with a pneumonic plague outbreak that occurred early in the twentieth century in Manchuria. Crowded, unsanitary conditions were implicated in that outbreak, said Peters, director of biodefense and professor of pathology, microbiology, and immunology at the University of Texas Medical Branch in Galveston, in a phone interview today.

During the Manchurian outbreak, people contracted plague either from fleas or from the marmots they killed for their pelts, he said. Once someone was ill, conditions were ripe for allowing the disease to spread.

"The living conditions were just absolutely terrible," Peters said. People often lived in cramped underground quarters with poor ventilation.

"It's believed that the coughs, combined with the poor ventilation and so on, led to the ready dissemination of the plague," Peters said.

He emphasized that absent such conditions, plague spreads less easily. It's appropriate to be concerned about plague, but equally important not to overreact to it, he said.

Peters added that African mines have been implicated in other outbreaks. Gold miners in South Africa have seen pneumococcal pneumonia, which probably has the same mechanism of spread, he said.

In addition, a suspected plague outbreak in the Ituri region in 2004 infected 1,042 people and killed 58, a United Nations agency reported in August 2004.

The WHO team hopes to be in the field by Tuesday, Bertherat said. Although he described existing medical treatment to date as appropriate, he also expressed a concern that local healthcare providers lack appropriate equipment.

Llelwyn Grant, a spokesman for the Centers for Disease Control and Prevention in Atlanta, told CIDRAP News this afternoon that the CDC was aware of the reports coming out of the Congo but had not been asked to provide any support.

"Right now this is a World Health Organization-led response," Grant said. "Of course we're on standby, but we've not been asked to assist."

Bertherat said the outbreak can be managed. "I'm not very afraid of a risk of a big extension all over the country, because it's a remote area," he said, adding that "this disease is well-known and easily treatable and preventable."

See also

Feb 18 WHO news release
http://www.who.int/csr/don/2005_02_18/en/

CIDRAP overview of plague
http://www.cidrap.umn.edu/cidrap/content/bt/plague/biofacts/index.html

CIDRAP News story on 2004 plague outbreak in Ituri region
http://www.cidrap.umn.edu/cidrap/content/bt/plague/news/august0204plague.html

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