How many malaria cases does Nigeria have every year? And how many deaths? You would think the obvious place to find out would be the World Health Organisation’s website, which has a whole section dedicated to the Roll Back Malaria Program. What you are met with when you get there, however, is a blizzard of different numbers. The Nigeria Country Profile in the 2005 World Malaria Report says there were 2.6 million reported malaria cases in 2003, a similar figure to the previous three years (in a country where malaria is endemic you’d expect incidence to remain roughly similar year on year). Sounds OK so far then. Despite nearly half of those infected being aged under 5, however (and therefore, you would think, weak and at high risk of death from such a dangerous disease), there were only 5,343 reported malaria deaths in 2003.
Perhaps Nigerian children are unusually robust, and therefore better equipped than kids in other countries to fend off a disease that (reportedly) kills hundreds of thousands of their peers each year worldwide. Alas, probably not, or at least not according to data posted elsewhere on the WHO site. The “country info” on Nigeria claims that there were 5.3 million reported malaria cases in Nigeria in 2007 – double the number four years earlier, and 10,000 reported deaths. OK, maybe an extra battalion or two of foreign mosquitoes has been called in by their fully sated Nigerian cousins to join in the bloodfest, or maybe reporting has improved or become more sensitive (not the same thing) over the past four years.
But then, on the same page, we are told that malaria accounts for “approximately 300,000 annual deaths.” So not the 10,000 “reported” deaths a few inches down the page, nor the 5,000 reported in the country profile, but 300,000. You might think the difference lies in the low figures being “reported” and the high ones extrapolated, but on closer inspection, the 5.2m cases in 2007 are described as “probable and confirmed”, and the 2.6m in 2003 “probable or clinically diagnosed.” Can’t tell the difference? Nor me.
Even if it is extrapolated, WHO has guessed that 10,000 reported deaths means 300,000 actual deaths – a thirtyfold difference. But if you do the same multiplication for the number of cases, you’d get 159 million cases – more than one bout of malaria per Nigerian per year, and nearly 50 million more even than the government (which is seeking aid to fight the disease so has an interest in inflating the numbers) claims on the World Bank website. It’s also almost triple the estimate of annual malaria cases in – wait for it – WHO’s latest country profile, released in 2008, which puts the number of cases at 57m and the number of deaths at, er, 225,000.
After all this, needless to say, I am no nearer to answering my two initial questions.
Update: It’s not just on malaria that the data are shaky, of course. David railed at even worse incompetence by UNAIDS a year ago.
