Enhancing country readiness
To strengthen the readiness and response capacity of those countries at risk from major epidemic-prone diseases such as plague, WHO provides international technical expertise when the potential consequences of an outbreak require external support. It also ensures the availability of those laboratory and drug supplies required for effective outbreak containment and helps to develop rapid diagnostic tests for diseases.
Essentially a disease of wild rodents, plague is a bacterial disease (Y. pestis) spread from one rodent to another by flea parasites and to humans by the bite of infected fleas. Untreated, mortality - particularly from pneumonic plague which is very contagious and lethal - may reach high levels. There is also a great risk of nosocomial infection. However, when rapidly diagnosed and promptly treated, plague may be successfully managed with antibiotics, reducing mortality from 60% to less than 15%. Outbreaks of plague are often linked to poverty, civil disturbances and war, and when the health infrastructure and facilities have broken down. If these outbreaks are not contained, they pose a health risk that go beyond national borders. Recent plague outbreaks in Algeria and Democratic Republic of the Congo provide good examples of how the WHO team assists countries to be on the alert for potential epidemics and to respond quickly to contain them when they occur.
Algeria: the disease returns after a long period of silence
The last human cases of plague occurred in Algeria in 1950. More than fifty years later, plague resurfaced in a rural area 25 kilometres south of Oran, a large commercial port on the Mediterranean. The Algerian health authorities reported several cases of bubonic plague to WHO and requested technical support to help contain the outbreak. In response, an international team from WHO, Institut Pasteur, Paris and the Centre de Recherche sur les Meningites et les Shistosomoses (CERMES), Niamey, Niger worked with the Ministry of Health and the local health authority on epidemiology, entomology and laboratory analysis of the plague outbreak. The team also provided necessary laboratory supplies and rapid diagnostic tests.
During the following weeks, a total of 11 confirmed and 7 suspected cases of plague were reported from the same area. The University Hospital in Oran confirmed the plague diagnosis. All cases were bubonic plague, with 2 cases later developing septicemia and coma.
The outbreak was contained quickly in part because the Ministry of Health had implemented a plan to face an emerging disease, following the global alert on SARS. The local health authorities had established admission rooms to treat patients and were able to help with investigating the epidemiology of the outbreak.
What became clear during this outbreak, however, was the likelihood that a natural focus for plague was emerging in the area. In previous outbreaks of plague in Algeria, the cases had all been imported, so it was particularly important to confirm the existence of this focus. Since this area was near an international harbour with a big population, the potential for major outbreaks was great.
In July of the following year, a WHO-sponsored team from the Institut Pasteur, Madagascar went to Algeria to investigate the suspected plague focus. The team confirmed its existence and was also able to show that it was still active. They trained staff from the Ministry of Health in surveillance of the rodents and in vector control.
Democratic Republic of the Congo: facing a hyper-endemic situation
In the north-eastern province of Ituri, more than 1000 suspected cases have been reported each year since 2001. Added to this high number of cases, the Democratic Republic of the Congo is also in the midst of a humanitarian crisis. All efforts at controlling plague have stopped: health education, vector control, deratting and laboratory analysis as well as active surveillance. With the breakdown of the health infrastructure during the civil war, antibiotics to treat plague and personal protective equipment for health care staff have become scarce.
In Bunia, Ituri province, WHO is working with the Institut Pasteur, Madagascar to train staff in the diagnosis and clinical treatment of plague. But more must be done on a large scale to avoid a major outbreak in the future, particularly in Bunia, where a refugee camp with 12,000 people are at high risk.
New rapid diagnostic test brings hope
In 2003 the Institut Pasteur, Madagascar developed a rapid diagnostic test for both pneumonic and bubonic plague antigens that was pilot tested by health workers in 26 sites in Madagascar. The tests were highly successful - results appeared after 15 minutes instead of the usual 15 days; the test was sensitive, reliable and easily to use at the patient's bedside. This intervention can help save lives:
- Deaths often occur because the patient is diagnosed too late for treatment
- The clinical picture is not very specific and misdiagnosis is common
- An outbreak of pneumonic plague, one of the most lethal and highly contagious infectious diseases, requires immediate public health measures to contain the spread
- Many suspected cases are not confirmed; plague is underreported because there is often no possibility of diagnosis.
This new tool is a great step forward. WHO has supported its production and testing in the Democratic Republic of the Congo. Already successful in an African setting, it now requires a field evaluation in other endemic countries, such as those in Central Asia, and in India and Viet Nam.