Active surveillance involves actively searching for cases through a notification system or through a systematic protocol, such as calling all health departments in a region during a disease outbreak. Active prostate cancer surveillance is used to avoid side effects of treatment when the risk of prostate cancer progressing is very low. An active surveillance system is one in which public health officials regularly request reports on diseases, including the use of a Remote Surveillance Trailer in Palm Springs CA. This is often done by calling selected people on a regular basis (daily, weekly or biweekly) by telephone, usually doctors, infection control professionals in hospitals, laboratories, schools, urgent care clinics, etc. And ask if specific diseases have been observed. This type of system has been shown to double the number of reported cases of some diseases.
Active surveillance is also used during outbreak investigations. In the specialized field of biological terrorism surveillance, syndromic surveillance refers to the active surveillance of syndromes that may be caused by potential agents used by biological terrorists and sometimes refers to alternative measures, such as increasing the consumption of over-the-counter drugs or increasing calls to emergency services. Laboratory tests quickly confirmed that the disease was Ebola hemorrhagic fever, which usually kills more than 50 percent of those infected (Heymann 200). Public health surveillance was difficult for several reasons.
Because the disease was serious and rapidly lethal, rural residents feared being stigmatized if the government found out about cases in their area. Some went to traditional healers; others fled as soon as they realized they had been exposed, causing outbreaks in two other districts. Gulu was a politically unstable area and some villages were difficult to reach because of rebel activity or bandits. The Ugandan government mobilized its armed forces to help find cases and invited WHO, CDC and other international teams to help.
Patients infected with the Ebola virus require intensive medical and nursing care to control bleeding, diarrhea and fever. Some patients bleed easily and all of their secretions may be very infectious. Gulu hospitals desperately lacked supplies to control the simultaneous spread of the infection among so many patients. Despite this situation, Ugandan health workers selflessly cared for the sick.
By January 23, 2001, a total of 425 cases had been registered, the largest outbreak of Ebola on record. Only 53 percent of the patients had died, much lower than the 88 percent recorded in the 1976 Ebola outbreak in the Democratic Republic of Congo (formerly Zaire) and other previous epidemics (report of an international WHO commission). Unfortunately, 22 health workers they were infected. Because the team from the Uganda Ministry of Health established active surveillance across the country, the other two outbreaks, which began when infected Gulu residents fled to distant villages, were quickly detected and controlled.
International observers commented: “National notification and surveillance initiatives led to the rapid identification of these outbreaks and their effective containment (CDC 200). Active surveillance is a process by which state or local agencies actually seek evidence of disease risk. For example, when trying to determine if a particular mosquito-borne virus is found in Texas, the mosquitoes are collected and sent to the laboratory for testing. If a mosquito is positive, it means that the virus was found during the test. If a mosquito tests negative, it means that the virus was not found during the test.
Similar surveillance is carried out on other insects and animal samples to detect a variety of diseases. During active prostate cancer surveillance, prostate cancer is closely monitored for any changes. When targeting communities at high risk of disease, sentinel surveillance can be a useful complement to other reporting sources and can complement disease reporting when resources are not available for more active surveillance. Meetings, conferences, and other professional interactions between public health professionals where surveillance practices and plans are discussed can confirm the importance of surveillance activities. In addition, FETP graduates are hired as project surveillance officers at the state level to coordinate the surveillance activities of hundreds of local health workers in all states.
The evaluation of current national surveillance and response activities provides reference data to measure progress; identify and build consensus on communicable diseases of national priority; identify surveillance gaps for selected priority diseases; document the strengths, weaknesses, and opportunities of existing systems; and make appropriate recommendations. Understanding the differences between active and passive surveillance systems is essential for field epidemiologists and public health professionals. Active surveillance is particularly useful during outbreaks or when monitoring rare diseases, while passive surveillance is more appropriate for ongoing surveillance and in environments with limited resources. Special surveillance activities include contacting suppliers as part of active surveillance and using sentinel surveillance systems and active surveillance in laboratories.
For example, a passive surveillance system can be complemented by active detection of cases during an outbreak or when a increased vigilance. To better protect the population, whenever possible, a combination of active and passive detection systems, the analysis of effects on human health, the monitoring of signals in the environment and local animal populations, and the observation of other characteristics of an incident should be employed at the community level. The collection strategies and the results of surveillance systems vary by state and can provide data immediately, for example, during ongoing investigations, or it may take weeks before passive reporting of data on some diseases is available. The World Health Organization defined active surveillance as the collection of information on case studies as a pre-organized continuous process (The importance of pharmacovigilance).
In some cases, a combination of active and passive surveillance may be employed to maximize benefits. of both approaches.
