Two days ago, I posted a report from Guinea in which WHO's tally of Ebola cases came in for criticism. Now Dr. Jody Lanard offers an explanation:
I'm sure you already noticed that the Guinea officials are citing confirmed cases only - whereas WHO is citing the total of the probable, suspected, and confirmed cases, which is the normative way of citing Ebola numbers during an Ebola outbreak.
The Guinea officials seem to be glossing over this distinction to justify calling the WHO numbers a mistake.
From WHO's Ebola case definitions during an outbreak, it looks as though suspected and probable cases are thought to have a high likelihood of being true Ebola cases. The definitions: http://bit.ly/1xEcaiK (pdf)
In the past, WHO and others have routinely and explicitly included "presumptive cases" (suspected + confirmed) in their totals for Ebola outbreaks, along with the break-outs of suspected vs. confirmed. (Example: Figure 2, graphing the largest Ebola outbreak to date, Uganda 2000, at: http://1.usa.gov/SKNtRn
The current West Africa outbreak/epidemic now has the second highest number of cases on record. (See WHO's "Chronology of previous Ebola virus disease outbreaks" table at http://bit.ly/1ivlbD0 )
I think the Guinea Ministry is just plain wrong, or making up its own definitions, or actually knows it is citing apples to WHO's oranges, or who knows what. In any case, their protest makes them look less credible. What a ghastly situation, from so many perspectives.