This morning I posted Haiti cholera epidemic at ‘600 cases a day’ – Health Minister and said that Health Minister Guillaume's 600 cases just didn't make sense. Almost at once, Ronan Kelly of FluTrackers sent a comment:
From May 31 to June 24, the total # of cases increased by 23,354 - an average of over 970 per day. Perhaps late reports are not counted in the Daily tally, but are added to the total. Hospitalizations totaled 14,315 - an average of 600 per day. Fatalities totaled 172 - over 7 per day on average.
I've been pondering that all day, and finally got some time to review the MSPP numbers starting with May 1 and ending 54 days later with June 24—the latest figures MSPP has given us. That, I assumed, would cover the start of the rainy season that's been blamed for the surge in cases.
I tallied the deaths, a total of 273 for an average of 5 per day. (Ronan's higher average is for May 31-June 24.) New cases in those 54 days totalled 35,561, for an average of 660 per day. So Ronan and Minister Guillaume were right. Moreover, 20,849 cases were serious enough to be hospitalized, for an average of 386 per day.
I went through the MSPP numbers one week at a time, and found these week-over-week increases in case numbers (hospitalizations in parentheses):
May 8: 2,821 cases more than May 1 (1,374)
What had happened in the last 5 days reported? I went back to MSPP and checked June 20-24:
So if you're tracking just the daily numbers, you get relatively low counts of cases and hospitalizations. But if you compare the daily numbers with the daily totals since October 2010, the dump of 14,755 cases and 13,257 hospitalizations is astounding.
The numbers for June 22, 23 and 24 are again routine, with about 200 cases per day and about 130 hospitalizations per day, and 5 deaths in those 3 days.
I have assumed, like Ronan, that occasional late reports were lumped in with the current day's numbers. The MSPP makes a point of noting departments that haven't reported on a given day, so presumably that explained occasional discrepancies in numbers of deaths.
But I have trouble imagining that sloppy paperwork in Nippes or Sud Est was the reason for omitting 14,755 cases from the June 20 tallies.
For the umpteenth time, I am not an epidemiologist. I'm just a guy in Vancouver with a pocket calculator and the MSPP reports. When I look at the tables in the June 21 report, I don't see a monster spike, or any explanation. Maybe I'm missing something obvious.
Something is going on here. I don't understand it. If someone out there can explain the cholera numbers for June 21, 2012, I would be very grateful.