For those of us living in developed countries, it may be difficult to imagine widespread plague outbreaks today. Antibiotics are widely available as well as informed doctors to prescribe them. Rats may near live near us in urban and rural areas, but not close enough that we really notice them. So, where do the 1,000-3,000 yearly plague cases reported by the World Health Organization (WHO) occur in the world today (WHO 2005a)? One such place is the Democratic Republic of the Congo (DRC), where one of the largest outbreaks in several decades was reported during the month of February 2005 (WHO 2005b).

Plague is infamous as the disease causing the Black Death in Europe during the 14th century. It is a zoonotic disease cycling mainly among small mammals and their fleas (WHO 2005a). It is spread to humans from the bite of rat-borne fleas. The fleas contain Yersinia pestis, a bacterium that infects the rat and is the causative agent of plague. When the rat host dies, the fleas often move to humans. Bubonic plague, the most common form, results when the fleas containing the bacteria, bite an individual and the bacillus enters the skin at the site of the bite. Once in the blood, it travels through the lymphatic system to the nearest lymph node.

The pneumonic form of the disease occurs in humans when the bacteria infects the lungs. It is the most virulent and least common form of plague (WHO 2005a). Only two percent of worldwide cases of plague each year are pneumonic (Timberg 2005a). Primary pneumonic plague results from inhalation of aerosolized infective droplets and can be transmitted from human to human without involvement of fleas or animals (WHO 2005a). It primarily attacks the lungs, is virulent and quickly fatal (Doctors Without Borders 2005).

The plague outbreak in the DRC was of the pneumonic form. Preliminary results from rapid diagnostic tests in the area of Bas-Uele district, Oriental province in the northern part of the country, confirmed pneumonic plague (WHO 2005b). The cases also had clinical features compatible with the disease. The incubation period ranges from 24-72 hours and death through asphyxiation comes within one day (Doctors Without Borders 2005). It is unclear how the first person to become infected with pneumonic plague transmitted the disease. Typically, pneumonic plague is due to a secondary spread from advanced infection of an initial bubuonic form (WHO 2005a). Although it is endemic to this region of the DRC, the current outbreak is unusual in the number of people infected (Doctors Without Borders 2005).

The outbreak was first reported in an open-pit diamond mine near the town of Zobia (UNIRIN 2005). According to an update March 3, 2005 from Dr. Eric Bertherat, head of the WHO team currently in the DRC and working with local residents to contain this plague outbreak, the suspected current cases and deaths may not be as high as originally thought (WHO 2005b). Initial reports suggested there might have been 400 cases, then it was believed there were 57 cases, including 16 deaths (UNIRIN 2005). As of March 14, there were as many as 130 cases, including 57 deaths (WHO 2005c). The exact number of cases was difficult to ascertain in the beginning of the outbreak because there were many pulmonary syndromes occurring in the local population that were exacerbated by poverty and poor sanitary conditions (UNIRIN 2005).

The mine is located in the middle of the forest far from major towns. It consists of a pit in the ground half-filled with stagnant water (WHO 2005b). It is controlled by Congolese soldiers. The miners are independent workers who work inside the pit looking for diamonds. At the end of the day, the workers return to a camp, about an hour's walk on a trail, also in the middle of the forest. The camp is similar to a large village, with small shops, diamond traders, prostitutes, and commercial activities (WHO 2005b). The sanitary conditions of the mining camp are extremely poor. The first diamonds were discovered in November 2004 and attracted miners from all over the province. At the beginning of January 2005, approximately 7,000 people were living in the camp (BBC News 2005). This included the miners, their families, and traders. At the beginning of March 2005, the population size decreased to 2,500 (WHO 2005b). Whether the population decrease was due to fear of death brought on by the plague outbreak, the lower water levels in the open pit mine from the season, which make mining for diamonds more challenging, or a combination of both these factors is not known (WHO 2005b).

WHO officials and teams from Medair and Doctors Without Borders went to the infected area with emergency stocks of antibiotics and other medicines (Timberg 2005a). The WHO teams met with local officials and inhabited a local mission. They sent teams to all the villages surrounding the mine and Zobia to assess the situation and implement case management. Case management is training of health care workers, orgainization of isolation wards, providing the health facilities with antibiotics, and personal protective equipment for the health care workers (WHO 2005b). The WHO teams also organized safe burials of infected bodies to decrease the risk of transmisssion (WHO 2005b).

The majority of the people possibly exposed to pneumonic plague from the Zobia diamond mine left the epicenter of the outbreak and fled to unknown locations (Timberg 2005b). This could result in a terrifying spread of the disease. Plague can easily be cured through a simple course of antibiotics, provided that the patient is found in time (Doctors Without Borders 2005). A suspected case was found in the city of Kisangani. After investigation, it was found that the suspected case had been a patient who received treatment near the mine and was half-cured before traveling to Kisangani (WHO 2005b). A WHO team had previously visited Kisangani and trained clinicians about plague. Therefore, they were able to recognize plague in this patient and alert officials.

Future outbreaks of plague, associated with the diamond mine in the eastern DRC, are likely (UNIRIN 2005). As the rainy season returns bringing more water for successful diamond mining, more workers will return to the mine (WHO 2005b). The miners are not very cognizant of the possibility of plague infection; they are more concerned with finding diamonds. The plague is just another infectious disease of the area (WHO 2005b). It is also thought that other outbreaks will occur more often in the future, in African countries, due to crisis situations, where decreasing sanitary and economic conditions exist (WHO 2005b).

References Cited

  1. BBC News. 2005. Plague outbreak kills 60 in Congo. Feb. 18, 2005. http://news.bbc.co.uk/1/health/4276627.stm.
  2. Doctors Without Borders. 2005. Doctors Without Borders intervenes in plague outbreak in congo. Press Release, Feb. 22, 2005. http://www.doctorswithoutborders.org/pr/2005/02-22-2005.shtml.
  3. [UNIRIN] United Nations Integrated Regional Information Networks. 2005. DRC: future plague outbreaks in the east likely, WHO says. UN Office for the Coordination of Humanitarian Affairs. March 4, 2005. http://www.irinnews.org/report.asp?ReportID=45916&SelectRegion=Great_Lakes.
  4. [WHO] World Health Organization. 2005a. Plague Fact Sheet, No. 267. Revised Feb. 2005. http://www.who.int/mediacentre/factsheets/fs267/en/print.html.
  5. [WHO] World Health Organization. 2005b. Plague in the Democratic Republic of the Congo - update 3. Mar. 3, 2005.
  6. [WHO] World Health Organization. 2005c. Plague in the Democratic Republic of the Congo - update 4. Mar. 14, 2005. <http://www.reliefweb.int/rw/RWB.NSF/db900SID/DDAD-6AHMB3?OpenDocument>.
  7. Timberg, C. 2005a. Pneumonic plague seen in Congo outbreak. Feb. 19, 2005. Washington Post, Washington, DC.
  8. Timberg, C. 2005b. Deadly plague outbreak feared in Congo. Feb. 18, 2005. Washington Post, Washington, DC. http://www.washingtonpost.com/wp-dyn/articles/A35329-2005Feb18.html?sub=AR.