Sentinel surveillance is carried out at specific sites or in specific populations and can be passive or active. Instead of reporting a specific condition in traditional active or passive surveillance, with sentinel surveillance, only certain hospitals or providers report the condition. Sentinel surveillance is a specific, focused approach to monitoring specific diseases or health conditions in a selected subset of the population, such as the use of a Remote Surveillance Trailer in Santa Barbara CA. Instead of collecting data from the entire population, sentinel surveillance involves collecting information from a group representative of health centers, regions or individuals who are considered to be at high risk of contracting the disease in question or when resources are too limited to test for entire populations. An example of this is described in the Gonococcal Isolate Surveillance Project (GISP), which has been monitoring antimicrobial resistance (AMR) trends in Neisseria gonorrhoeae since 1986 in selected clinics and laboratories in the U.S.
UU. In a sentinel surveillance system, a pre-established sample of reporting sources agrees to report all cases of defined diseases, which could indicate trends in the entire target population (Birkhead and Maylahn, 2000). When properly implemented, these systems offer an effective method for using limited resources and allow for quick and flexible monitoring and investigation of suspected public health problems. Some examples of sentinel surveillance are networks of private doctors who report cases of influenza or a laboratory sentinel system that reports cases of certain bacterial infections in children.
Sentinel surveillance is excellent for detecting major public health problems, but it can be insensitive to rare events, such as the early onset of a new disease, because these infections can occur anywhere in the population. Active surveillance centers can be medical clinics, hospitals, or health centers that serve certain at-risk populations. These could be networks of individual professionals, such as primary care doctors. These sentinels usually provide an early assessment of the incidence of an outbreak and are very useful for diseases that occur frequently. Medical sentinels are often used for influenza surveillance.
However, in some cases, physician networks can be used to detect rare events, such as acute flaccid paralysis. Sentinel events are measured events that can be used to draw attention to problems in practices, procedures, or systems. For example, maternal mortality has long been used as an indicator of the effectiveness of maternal and child health programs. Active surveillance can produce early, timely and complete information, but the methodology must be carefully developed and the data must be interpreted.
Active sentinel systems can also be costly to maintain. Other types of surveillance are used in public health, such as syndromic surveillance, sentinel surveillance and environmental surveillance. Each one has unique characteristics and is interested in capturing specific types of data. Syndromic surveillance is a passive system created from the symptomatology of medical records in a database of electronic medical records in all health networks.
This is an algorithm-based approach that seeks to detect spikes in major symptoms (i.e., a sentinel surveillance system uses only selected locations or sites to collect data to represent the entire population under surveillance). These systems are best used when a high level of detail is needed about certain health conditions, but logistics are too complicated and expensive to implement in all potential data collection centers. Environmental surveillance seeks environmental indicators that are correlated with upward and downward trends in the presence of human diseases. For example, SARS-CoV-2 surveillance in wastewater has been implemented in several countries to detect the presence of the virus in untreated wastewater, an indicator of the circulation of the virus in communities. Another example is mosquito surveillance, in which traps are placed to collect mosquitoes that are then tested for the presence of specific zoonotic diseases, such as West Nile virus.
These surveillance systems provide health intelligence and serve as the basis for planning and prevention initiatives. Surveillance is the process or system for tracking cases of risk factors, medical conditions, cases of diseases, adverse events, etc. It is often used to track the incidence of a disease or the side effects of drugs or vaccines. The two basic types of surveillance are active and passive. Passive surveillance is the collection of data from those who voluntarily report it, such as hospitals, healthcare providers, parents, or health departments. 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.
The Network for Active Surveillance of Foodborne Diseases (FoodNet) is an example of this type of surveillance. Surveillance activities have many measurable components (surveillance indicators), such as the timeliness of notification, the completeness of the notification, and the ability to obtain all the necessary information during the investigation of cases. While not a substitute for the timely notification of suspected cases, these searches can complement reporting when resources are not available for more active surveillance. National surveys, such as the National Health and Nutrition Examination Survey (NHANES), iii, are also considered active surveillance.
This type of surveillance is carried out when high-quality data is needed, passive systems cannot provide this data, and resources are too scarce for full, population-based active surveillance. In this toolkit, the term “surveillance system” refers to all disease surveillance activities undertaken in a country or jurisdiction. The disadvantage of active surveillance is that it requires more resources and requires more personnel and financial resources. 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.
While surveillance needs in the developing world seem to differ from those in the developed world, the basic problems are similar. Surveillance of foot-and-mouth disease outbreaks investigated by public health authorities is often a useful means of monitoring both the security of the food supply and the activities of the public health system. The advantage of active surveillance is that it generally provides more complete data, while passive surveillance depends on other people (who have many roles besides reporting the disease) to report cases. In addition, FETP graduates are recruited as project surveillance officers at the state level to coordinate surveillance activities for hundreds of local health workers in all states.
Sentinel surveillance systems can also be installed in schools, day care centers, hospitals, or other institutions that serve specific populations. However, long-term active surveillance systems can also be established to determine the incidence and epidemiological and laboratory characteristics of specific pathogens or conditions of concern to public health.
