Describe the objective of vector surveillance.
The objective of vector surveillance is public protection against vector-borne diseases. The vector surveillance program was designed to protect the public from animal related health issues. It is used to determine changes in geographical distribution and density of the vector. It will also help identify areas of high density infestation and population increases. Vector control is environmental management consisting of planning, organization, carrying out and monitoring activities for the modification or manipulation of environmental factors. (WHO, 1980)
Modifications are made to the environment managed by transformations of a physical nature that has long lasting effects for vector habitats. Manipulation of the environment is managed by producing temporary undesirable breeding ground conditions for vector habitats in making changes that reduce human contact with vector pathogens (WHO, 1980). Some diseases associated to animals that are passed onto humans are Lyme disease it is contracted from ticks and has three stages. The first stage is the primary stage with symptoms of chills, fever, headaches and muscle pain much like the flu. The second stage affects the central nervous system and heart. The third stage affects the skin, brain and nervous system, and muscles, bones, and cartilage (ADAM, 2009).
Hantavirus is contracted from rodents occurs in two phases. The first phase is generally evident by the third to seventh day. It includes flu like symptoms, with pain of the shoulders, lower back and thighs. Nausea and vomiting are usually present, with diarrhea and dizziness. The second phase is evident four to ten days after and includes cough, shortness of breath and difficulty breathing (BCPH, 2007).
The Plague is contracted from fleas. The fleas latch onto a host such as a rodent. They infect the host, and when that host dies congregate in wait of another host. There are three types of plague. Bubonic is the most common and is infection in a lymph node. Septicemic is infection in the blood stream, and pneumonic is infection in the lungs (BCPH, 2007).
Compare the strengths and weaknesses of sentinel surveillance systems
Strengths
Data collection is traceable and organized.
Can be either passive or active depending on the objective which makes it flexible for the participants.
It is effective as an early warning tool.
Detects initial or resurgence of a targeted disease vector.
Farmers voluntarily participate because of the data collection and organized information.
Possibility to estimate and extrapolate morbidity measures indicators for a wider population range.
Its broad range including flexibility and focus.
Weaknesses
After a certain time there are immunological techniques that will not detect antibody presence resulting in the disease going undetected.
Diagnostic testing with antigen detection has their limitations.
Efficiency of diagnostic procedures is low when in an uncommon area.
If sero-prevalence is low, it produces a false positive result generating a cascade of unnecessary actions.
Depending on method of sentinel or herd selection data collection may be biased.
Random selection will not focus on transport method
Voluntary farmer participation has a lot of dropouts which impacts the reliability of the sentinel herd system.
Racloz et al (2007) recommended different strategies for setting up a sentinel surveillance system for an endemic disease vs. for an early warning system. Describe the differences between the recommended strategies.
Sentinel surveillance systems involve elaborate and systematic action plans with focus on testing, control and response strategies. Some endemic and early warning strategies are
Endemic Strategies
Setting up the sentinel surveillance system for endemic disease involves either correlating random or non-random selection of a herd and of the individual animal in the herd.
Selection is based on the main objective in surveillance of an existing disease.
The Study dynamics of the existing disease or vector agent.
Test the efficacy of control strategy.
Estimate exposure risk.
Early Warning Strategies
Setting up the sentinel surveillance system for an early warning system involves defining the selection of a specific region where the disease is known to not exist.
The location must be an area that is ideal for the disease to flourish once infected.
Selection is based on main objective in surveillance of areas free of disease or to identify re-emergence of disease or vector agent.
It is important to select a location that is a high risk zone.
Can be identified by climatic and geographic factors.
It is also recommended that when establishing a vector-borne disease it should be made up of two components sentinel herd host surveillance and an entomological surveillance team. This will assist in determining the composition of the vector species in monitoring changes and their frequency (WHO, 1980).
This setting has been used in establishing well known diseases such as West Nile, Eastern and Western equine encephalitis, also La Crosse and St. Louis, Bluetongue, Akabane, and Bovine Ephemeral Fever. The emphasis was on testing methods, diagnostics, and frequency in accordance with antigens, and antibodies. When the objective is correctly determined the success of sentinel herd surveillance counts on following the criteria regarding location, sentinel species and diagnostic methods (WHO, 1980).
Modifications are made to the environment managed by transformations of a physical nature that has long lasting effects for vector habitats. Manipulation of the environment is managed by producing temporary undesirable breeding ground conditions for vector habitats in making changes that reduce human contact with vector pathogens (WHO, 1980). Some diseases associated to animals that are passed onto humans are Lyme disease it is contracted from ticks and has three stages. The first stage is the primary stage with symptoms of chills, fever, headaches and muscle pain much like the flu. The second stage affects the central nervous system and heart. The third stage affects the skin, brain and nervous system, and muscles, bones, and cartilage (ADAM, 2009).
Hantavirus is contracted from rodents occurs in two phases. The first phase is generally evident by the third to seventh day. It includes flu like symptoms, with pain of the shoulders, lower back and thighs. Nausea and vomiting are usually present, with diarrhea and dizziness. The second phase is evident four to ten days after and includes cough, shortness of breath and difficulty breathing (BCPH, 2007).
The Plague is contracted from fleas. The fleas latch onto a host such as a rodent. They infect the host, and when that host dies congregate in wait of another host. There are three types of plague. Bubonic is the most common and is infection in a lymph node. Septicemic is infection in the blood stream, and pneumonic is infection in the lungs (BCPH, 2007).
Compare the strengths and weaknesses of sentinel surveillance systems
Strengths
Data collection is traceable and organized.
Can be either passive or active depending on the objective which makes it flexible for the participants.
It is effective as an early warning tool.
Detects initial or resurgence of a targeted disease vector.
Farmers voluntarily participate because of the data collection and organized information.
Possibility to estimate and extrapolate morbidity measures indicators for a wider population range.
Its broad range including flexibility and focus.
Weaknesses
After a certain time there are immunological techniques that will not detect antibody presence resulting in the disease going undetected.
Diagnostic testing with antigen detection has their limitations.
Efficiency of diagnostic procedures is low when in an uncommon area.
If sero-prevalence is low, it produces a false positive result generating a cascade of unnecessary actions.
Depending on method of sentinel or herd selection data collection may be biased.
Random selection will not focus on transport method
Voluntary farmer participation has a lot of dropouts which impacts the reliability of the sentinel herd system.
Racloz et al (2007) recommended different strategies for setting up a sentinel surveillance system for an endemic disease vs. for an early warning system. Describe the differences between the recommended strategies.
Sentinel surveillance systems involve elaborate and systematic action plans with focus on testing, control and response strategies. Some endemic and early warning strategies are
Endemic Strategies
Setting up the sentinel surveillance system for endemic disease involves either correlating random or non-random selection of a herd and of the individual animal in the herd.
Selection is based on the main objective in surveillance of an existing disease.
The Study dynamics of the existing disease or vector agent.
Test the efficacy of control strategy.
Estimate exposure risk.
Early Warning Strategies
Setting up the sentinel surveillance system for an early warning system involves defining the selection of a specific region where the disease is known to not exist.
The location must be an area that is ideal for the disease to flourish once infected.
Selection is based on main objective in surveillance of areas free of disease or to identify re-emergence of disease or vector agent.
It is important to select a location that is a high risk zone.
Can be identified by climatic and geographic factors.
It is also recommended that when establishing a vector-borne disease it should be made up of two components sentinel herd host surveillance and an entomological surveillance team. This will assist in determining the composition of the vector species in monitoring changes and their frequency (WHO, 1980).
This setting has been used in establishing well known diseases such as West Nile, Eastern and Western equine encephalitis, also La Crosse and St. Louis, Bluetongue, Akabane, and Bovine Ephemeral Fever. The emphasis was on testing methods, diagnostics, and frequency in accordance with antigens, and antibodies. When the objective is correctly determined the success of sentinel herd surveillance counts on following the criteria regarding location, sentinel species and diagnostic methods (WHO, 1980).
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