'Sumpffieber' (ii) was a German operation against Jews and other 'non-desirables' in the Latvian region of the German-occupied western USSR (21 August/21 September 1942).

As the German forces advanced to the east in 'Barbarossa' from 22 June 1941, there left in their wake small groups of Soviets troops who then combined with other anti-German elements to create partisan forces which soon grew in size and capability, and then became a major factor in the denial, or at least the slowing, of the movement of men, weapons, equipment and supplies to the Germans front-line formations. Early in 1942 the Germans decided that the time was more than ripe to tackle this rear-area irritant in several parts of the occupied western USSR, and most especially Belorussia, through which the supplies for Generalfeldmarschall Günther von Kluge’s Heeresgruppe 'Mitte'. At the same time Reichsführer-SS Heinrich Himmler was working on plans to eliminate the Jews and other non-Aryan elements of the population of the conquered territories in preparation for their 'Germanisation' through the movement of large numbers of ethnic Germans into the area. On 7 August Himmler signed the document which institutionalised the part to be played by the SS and local anti-Jewish elements in the rooting out and destruction of the Jews. Thus genuine anti-partisan and 'racial-cleansing' operations often proceeded in tandem, the latter being characterised as anti-partisan and anti-gang undertakings.

Under the command of SS-Obergruppenführer Friedrich Jeckeln, the Höherer SS- und Polizeiführer des SS-Oberabschnitts 'Ostland', 'Sumpffieber' (ii) was launched by two German and three Latvian battalions operated as the Gruppe 'Binz' and Gruppe 'Barkholt', which were supplemented from 28 August by the Gruppe 'Schröder' with the men of five paramilitary police armoured trains, one company of combat-capable Waffen-SS war correspondents, four Latvian battalions, and the Latvian Sonderkommando 'Arājs'.

The German and Latvian operation destroyed several villages, killed 389 'guerrillas' in battle, summarily executed 1,274 'suspects' and 8,350 Jews executed, and seized 1,217 persons for deportation. Another 6,000 Jews were killed when the ghetto in Baranovichi was attacked and razed between 22 September and 2 October.