Disease surveillance
For most of recorded history, reporting incidences of disease outbreaks has been been a matter of routine record keeping. The number of cases could be gathered from hospitals - who could be expected to see most of the occurrences - collated, and eventually made public. Although this process took some time, this was not a particular concern, because of the length of time that it took news to travel from place to place. With the advent of modern communication technology, this has changed dramatically. Organizations like the World Health Organization and the Center for Disease Control now routinely report cases and deaths from significant diseases within days - sometimes within hours - of the occurrence. Further, there is considerable public pressure to make this information available quickly and accurately.
For diseases that spread relatively slowly, like AIDS and Tuberculosis, the process of reporting cases is little different from historical practice. For rapidly evolving and potentially rapid spreading diseases, like SARS and Avian influenza, the situation is quite different. In this article, we look at some of the factors that lead to specific results being reported. The goal of the article is to help readers interpret these results as reported.
World Health Organisation
The World Health Organisation is the lead agency for coordinating global response to major diseases. The WHO maintains Web sites for a number of diseases, and has active teams in many countries where these diseases occur. During the SARS outbreak in early 2004, for example, the Beijing staff of the WHO produced updates every few days for the duration of the outbreak. [1] Beginning in January, [[2004], the WHO has produced similar updates for H5N1. [2] These results are widely reported and closely watched.
The WHO faces numerous challenges in reported results.
Political challenges
As the lead organization in global public health, the WHO occupies a delicate role in global politics. It must maintain good relationships with each of the many countries in which it is active. As a result, it may only report results within a particular country with the agreement of the country's government. Because some governments regard the release of any information on disease outbreaks as a state secret, this can place the WHO in a difficult position. The result is that there may be cases reported in the media significantly before the WHO reports the same cases.
This is not the only political challenge facing the WHO. The government of Taiwan lodged a protest with the WHO when the latter denied its status as free of H5N1, because the WHO considers Taiwan to be politically part of China, which does have occurrences of H5N1. [citation needed]
Technical challenges
The second group of challenges are technical and, in part, economic. Testing for a disease can be expensive, and distinguishing between two diseases can be technically prohibitively difficult in many countries. One standard means of determining if a person has had a particular disease is to test for the presence of antibodies that are particular to this disease. In the case of H5N1, for example, there in a low pathogenic H5N1 strain in wild birds in North America that a human could conceivably have antibodies against. It would be extremely difficult to distinguish between antibodies produced by this strain, and antibodies produced by the Asian lineage of H5N1. Similar difficulties are common, and make it difficult to determine how widely a disease may have spread.
The second technical challenge, as previously mentioned, is a combination of technical and economic. There is currently little available data on the spread of H5N1 in birds in Africa and Asia. Without such data, predicting how the disease might mutate in the future is difficult. The amount of information that scientists wish they had, but are practically unable to obtain, could be the subject of entire articles, and might include:
- Surveillance of wild bird populations
- Cell cultures of particular strains of diseases
and so on.