Colombia receives 1.5 million doses of vaccine to face yellow fever outbreak
Washington, DC, January 23, 2004 (PAHO)—Colombia today received 1.5 million doses of vaccines to face an outbreak of jungle yellow fever that has affected three departments of that country, with 27 cases and 8 deaths reported in recent weeks.
The Pan American Health Organization (PAHO) succeeded in making a purchase of vaccines from Brazil through the Organization’s revolving vaccine fund in record time to fight the outbreak.
This stock adds to the 500,000 doses offered by Venezuela to face a resurgence of this disease that has been affecting part of the country since 2002. The outbreak extended from the Department of North Santander and was moving toward the north, to the departments of Guajira, Cesar, and Magdalena. The situation became especially delicate because cases arose in places very close to densely populated cities like Santa Marta and Valledupar, which are also important tourist centers with a high index of Aedes aegypti infestation, according to PAHO’s update on Emerging and Reemerging Infectious Diseases.
Few cases were reported among tourists who visited the Tayrona Park during the peak end-of-year tourist season. During this period, Tayrona Park had some 25,000 visitors, with 2 percent foreign tourists, PAHO’s bulleting noted.
The Ministry of Health has declared a state of emergency and is in the process of massive vaccination efforts aimed at the population over one year of age in the affected areas, where almost 3 million people live. Faced with this emergency, Colombia is purchasing vaccines through PAHO so the country can deal with the demand.
A series of factors favor the urbanization of yellow fever, such as not vaccinating the entire population in enzootic areas; the occurrence of cases near big cities with a high index of A. aegypti infestation; and travelers entering enzootic areas without previous vaccination. "These factors, along with social problems and armed conflict in the area where the outbreak occurs, constitute a high risk of yellow fever becoming urbanized in the Region of the Americas," the PAHO publication noted.
To avoid situations like these and the reurbanization of yellow fever, PAHO recommends vaccination in areas where yellow fever is enzootic, as well as in areas with an index of household A. aegypti infestation of over 5 percent, with the goal of vaccinating 100 percent of the area residents. This includes incorporating yellow-fever vaccination into routine child vaccination schemes and vaccinating all travelers who visit enzootic areas. Countries should keep on hand an adequate supply of vaccine both for routine programs and for dealing with outbreak situations, and maintain an efficient surveillance network to detect any outbreak. An integrated program of vector surveillance and control should keep down the density of A. aegypti in urban centers. This measure will in turn help prevent dengue outbreaks.
Yellow fever is an acute infectious disease, caused by a virus of the Flavivirus family. Humans contract the infection from the bite of an infected mosquito. The virus is injected subcutaneously and, after reproducing locally, it spreads through the entire organism. The disease is characterized by acute onset and constitutional symptoms followed by a brief remission and a recurrence of fever, hepatitis, and, in some instances, renal failure, shock, and generalized hemorrhages.
The virus remains silent in the body during an incubation period of three to six days. There are then two disease phases. While some infections have no symptoms, the acute phase is normally characterized by fever, muscle pain, headache, shivers, loss of appetite, nausea and vomiting. The high fever is often associated with a slow pulse. After three to four days most patients improve and their symptoms disappear.
However, 15 percent enter a "toxic phase" within 24 hours. Fever reappears and several body systems are affected. The patient rapidly develops jaundice and complains of abdominal pain with vomiting. Bleeding can occur from the mouth, nose, eyes and/or stomach. Once this happens, blood appears in the vomit and feces, and kidney function deteriorates, ranging from abnormal protein levels in the urine to complete kidney failure with no urine production. Half of the patients in the "toxic phase" die within 10-14 days. The rest recover without significant organ damage.
There is no specific treatment for yellow fever, though dehydration and fever can be corrected. Intensive supportive care may improve the outcome for seriously ill patients, but is rarely available in poorer, developing countries.
Vaccination is the single most important measure for preventing yellow fever. In populations where vaccination coverage is low, vigilant surveillance is critical for prompt recognition and rapid control of outbreaks. Mosquito control measures can be used to prevent virus transmission until vaccination has taken effect.
PAHO was established in 1902 and is the world's oldest public health organization. PAHO works with all the countries of the Americas to improve the health and the quality of life of people of the Americas. It serves as the Regional Office for the Americas of the World Health Organization (WHO).
PAHO Member States today include all 35 countries in the Americas. France, the Kingdom of the Netherlands, and the United Kingdom of Great Britain and Northern Ireland are Participating States. Portugal and Spain are Observer States, and Puerto Rico is an Associate Member.
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