By farm class, this figure for the total number of positive laboratory swine accessions/diagnostic case submissions as follows between the weeks of 15 April and 22 December: suckling, 404 (+22); nursery, 369 (+21); grower/finisher, 591 (+35); sows/boars, 225 (+7) and 377 (+34) unknown. The total is up 116 from the previous week but that figure appears to have been adjusted upwards since the previous reported; thr week of 15 December saw a record 185 new positive results.

No states have reported their first positive results in the last week and so the total number of states affected remains at 20. Those states with 20 or more positive tests are: Iowa, 699; North Carolina, 275; Oklahoma, 269; Minnesota, 195; Kansas, 139; Indiana, 56; Ohio, 55; Illinois, 53; Colorado, 35; Pennsylvania, 28 and Texas, 25.

For the most recent week, Iowa once again leads the 'league table' in the number of new positive results, accounting for 60 of the total of 116 new cases, followed by Minnesota with 17 and Illinois with eight. Of Iowa's newest cases, 24 were in grower-finishers with 14 in suckling piglets and 12 in nurseries.

In mid-June, the reporting system was adjusted. For the weeks prior to 16 June, laboratories were able to provide diagnostic case submissions as well as the number of premises testing positive for the PED virus (PEDv). Since 16 June, the data refer only to diagnostic cases submissions ('swine accessions').

From the week of 16 June to week of 22 December, the total number of biological (swine) samples testing positive is 6,006, up 345 from the previous week. The most-affected states by this measure are: North Carolina, 1,622; Iowa, 1,218; Oklahoma, 1,003; Kansas, 632; Minnesota, 502; Illinois, 210; Ohio, 191; Colorado, 115, Pennsylvania and Texas, both with 84; Missouri, 88 and Indiana, 71. Other states, where positive, reported 50 positives or fewer.

In the most recent week reported (week of 22 December), the following states reported one or more positive results: Iowa (93), Illinois (53), Indiana (2), Kansas (19), Michigan (8), Minnesota (75), Missouri (15), North Carolina (48), Ohio (11), Oklahoma (9) and Texas (10).

For the last week, there are some difference between the states in terms of the type of farm where the positive biological samples originated. As by the previous measure, the majority of Iowa's positive samples were from grower-finisher units, whereas sows and boars accounted from most of those positive from Minnesota and those in North Carolina were in suckling piglets. The samples sizes are too small to draw any conclusions from these observations.

The total number of environmental samples testing positive for PEDv has been reported weekly since the week of 16 June. The total has reached 1,333, which is 33 more than the previous week's figure. The totals for each state are as follows (with the increase in brackets: Colorado, 18 (=); Iowa, 171 (+8); Illinois, 39 (+1); Kansas, 177 (+15); Michigan 1 (=), Minnesota, 420 (+1); Missouri, 35 (=); North Carolina, 73 (+1); Nebraska, 8 (=); New York 1 (=); Ohio, 47 (=); Oklahoma 258 (+2); Pennsylvania, 9 (=); South Dakota, 2 (=); Tennessee, 8 (+5); Texas, 1 (=); Virginia, 2 (=); unknown, 63 (=).

These data are collated by USDA APHIS VS NVSL National Animal Health Laboratory Network (NAHLN) and cited by the American Association of Swine Veterinarians (AASV) in a report dated 31 December.