The initial steps in investigating measles outbreaks in Australia
The CDC lists steps for investigating measles as:
- Establish the existence of an outbreak by comparing the number of cases detected against the available data from local health facilities, which include discharge records and mortality or use information from the state or national records (CDC, 2012).
- Verify the diagnosis through laboratory tests irrespective of patients’ age. Case investigation should proceed alongside laboratory tests. Ensure a proper confirmation of the disease.
- Develop a working case definition based on confirmed, probable or possible cases to provide ease of investigation. Unverified cases should be confirmed after laboratory test results.
- Conduct descriptive epidemiology by noting time, place and persons, drawing and interpreting an epidemic curve
- Develop hypotheses to evaluate the source, modes of transmission and causes
- Assess hypotheses epidemiologically through fact comparison
- Reconsider hypotheses when necessary
- Adopt control and prevention strategies
- Communicate outcomes to stakeholders
A focus on outbreaks, control and surveillance both in Australia and abroad
Outbreak
There have been several cases of measles outbreaks in Australia and other parts of the world in the recent past. Although other countries have eliminated measles, there are still some random reported cases.
The measles virus spreads fast and is highly contagious. In some cases, sources of the outbreak may remain unconfirmed, but data gathered during the investigation may provide possible sources, including tourists and other travelers.
The numbers of reported cases of measles globally differ significantly. While some countries have recorded high rates of measles outbreaks, particularly developing ones, developed nations have managed to control measles outbreaks (Simons et al., 2012).
Even countries that claim to have eliminated measles still experience random outbreaks. As a result, they have reviewed their guidelines on managing potential measles outbreaks. Such directives assist healthcare providers to manage the spread of measles and limit the possibility of further spread and any complications.
Control
Following the successful eradication of measles in the US and the UK, other countries started to review their approaches to measles control. Australia had adopted a Measles Control Campaign to eradicate the disease. This strategy involved the greater part of the World Health Organisation’s efforts to eliminate measles globally.
Some control approaches are reactive rather than proactive. For instance, developing countries have recorded several deaths among children because of measles outbreaks. Since the 1960s, there has been an appropriate vaccine for managing measles and most countries have relied on the vaccine to control measles.
Today, the common practices among countries across the world involve regular immunization of children of different ages. However, control methods and campaigns have remained reactive based on the detection of new cases. Control methods also involve data collection to assist in explaining possible sources of the outbreak and outcomes of the vaccine among the immunized children.
Surveillance
Australia and other countries have adopted national measles surveillance systems and response strategies to control outbreaks. The process involves data collection on suspected cases of measles and transmission to national databases for comparison with existing data.
Healthcare providers rely on the WHO case classifications to identify and report cases of measles. They also identify and report specific symptoms associated with the disease in surveillance processes. In addition, investigators also collect data on measles-related deaths while probable cases are sent to the laboratory for investigation.
During any outbreaks, countries enhance surveillance systems, reinforce case definitions, categorization of cases and data collection. There is also enhanced sharing of information about the outbreak, monitoring intervention outcomes and verifying collected data with previous records.
References
CDC. (2012). Investigating an Outbreak. Web.
Simons, E., Ferrari, M., Fricks, J., Wannemuehler, K., Anand, A., and Burton A. (2012). Assessment of the 2010 global measles mortality reduction goal: results from a model of surveillance data. Lancet, 379(9832), 2173–8. Web.