Plague transmission cycle.

<p>A) <i>Plague cycle in the rural area of Madagascar</i>. Rural plague foci of the highlands are organized into three habitats: houses (arrow), sisal hedges (arrowhead), and rice fields (star). The black rat, <i>R. rattus (3)</i>, is the main rodent involved in transmission associated with <i>X. cheopis (1)</i> and the endemic flea <i>S. fonquerniei (2)</i>. (Photo of plague foci: S. Rahelinirina). B) <i>Plague cycle in the urban areas of Madagascar</i>. Urban plague occurs mainly in the cities of Antananarivo (Isotry Market, left) <i>(7)</i> and Mahajanga (Abattoir suburb, right) <i>(6)</i>. <i>R. norvegicus (4)</i> and <i>X. cheopis (1)</i> are involved in each focus. The Asian shrew (<i>S. murinus</i>) <i>(5)</i> has long been suspected to play a major role in the epidemiological cycle of plague in Mahajanga. C) <i>Plague cycle in the forest area</i>. A sylvatic transmission occurs in Madagascar with <i>R. rattus (3)</i> and endemic micromammals (such as <i>Setifer setosus</i>) <i>(8)</i> as reservoirs. <i>S. fonquerniei (2)</i> is the major vector of the disease in this area. The role of other endemic fleas <i>(9)</i> is not yet determined. (Photo of forest of Ampahitra: S. Telfer; <i>Setifer setosus</i>: V. Soarimalala).