South Dakota Influenza summary for the week ending December 23, 2017
December 29, 2017

·      121 new confirmed* cases of influenza were reported last week.   421 confirmed cases cumulative so far this season:  384 Influenza A and 37 Influenza B.  *Lab confirmed:  PCR, culture or DFA. The number of laboratories using rapid confirmatory tests has increased, which may account for some of the increase in confirmed cases observed this influenza season.

·      17.4% positive rapid antigen tests reported statewide (122 positives out of 702 individuals tested last week).    Total 6,294 tests performed so far this season.

·      19 new influenza-associated hospitalizations reported last week (Brookings, Codington, Day, Grant, Hamlin, Jackson, Lawrence, Lincoln, Mellette, Minnehaha, Oglala Lakota, Pennington, Tripp, Walworth, and Yankton counties).  Total of 68 hospitalizations so far this season.

·      One influenza-associated death reported last week (Davison County). Total of 2 deaths so far this season.

·      2.58% of clinic visits were for influenza–like illness (ILI), 34.1% of ILI visits were children 4 years of age and younger.

·      1.8% of K–12 students were absent due to any illness, range 0% – 8% absent (56 schools reporting).

 

Season	Dominate virus	Deaths	Hospitalizations	Confirmed cases (Culture, PR, DFA)	Peak week
2017-2018	Pending	2	68	421	Pending
2016-2017	A(H3N2)	44	965	2,078	February 3rd week
2015-2016	A(H1N1)	9	161	786	March 2nd week
2014-2015	A(H3N2)	63	793	1,703	January 1st week
2013-2014	A(H1N1)	14	239	659	January 1st week
2012-2013	A(H3N2)	38	365	993	January 2nd week
2011-2012	A(H3N2)	17	164	505	March 3rd week
2010-2011	A(H3N2)	20	290	860	February 3rd week
2009-2010	A(H1N1) pandemic	24	431	2,303	October 2nd week
2008-2009	A(H1N1)	4	134	525	March 1st week
2007-2008	A(H3N2)	22	361	684	February 4th week
2006-2007	A(H1N1)	6	132	400	February 3rd week
2005-2006	A(H3N2)	11	Not reportable	636	March 2nd week
2004-2005	A(H3N2)	42	Not reportable	684	February 3rd week
Median (2004-2017)		20	290	860	February 3rd week

Influenza surveillance website:  http://flu.sd.gov.

National Synopsis:   Influenza activity sharply increased in the past week in the United States.  Nationally, 89% influenza A and 11% influenza B of 831 positive specimens tested in public health laboratories.

Influenza activity by state:

–    WIDESPREAD (highest level) influenza activity in 36 states; including South Dakota;

–    REGIONAL activity in 13 states;

–    LOCAL activity in 1 states

–    SPORADIC activity in 0 states;

–    NO activity in 0 states.

Our neighboring states:

–   WIDESPREAD activity: North Dakota, Minnesota, Nebraska, Wyoming Montana and
South Dakota.

–   REGIONAL activity: Iowa