[A new rickettsiale of Gambia rats (Cricetomys gambianus) in Senegal : Grahamella kaniae n. sp. (Bartonellacae)].
Giant Rat (Cricetomys gambianus Waterh) is a big rodent very common in West Africa. Its burrow is bordering upon huts and lofts in the african villages. Omnivorous, it is more or less a commensal of the man. The blood of 20 adults male and female specimens captured in the Sine Saloum (Fatik) and Presqu'Ille du Cap Vert (Dakar) regions was examined (peripheric blood smears). In 60 p. 100 (12/20) of hemograms, an intraerythrocytic organism of the genus Grahamella Brumpt 1911 was observed. Rod-shaped and carmine-coloured by staining technic of May-Grünwald and Giemsa, it is an unflagellate element. Slightly narrowed in the median part, it is 1 to 1.5 mu long and 0.25 mu wide. Multiplication by bipartition in the red cell plasma that may be occupied by 30 to 40 Grahamella. In chronic infection without morbid signs. 1/50 to 1/60 hematocyte is only infected. Electron micrograph of thin sections of red cells infected by Grahamella shows an element with a cell wall surrounding cytoplasmic masses which are enclosed in a cytoplasmic membrane. Nuclear region (bundles of moniliform chains = nucleic acids) is not surrounded by a nuclear membrane. Intraerythrocytic position. Bipolar densification of the cell plasma. The prokaryote is directly included in the erythrocyte plasma : no host cell vacuole is visible. Stress, polyinfection, polyparasitism or immuno-depressor effects, determine an intense proliferation of Grahamella by micrococcus elements (diameter : 0.1 to 0.3 mu) invading the systemic circulation. In that cases : septicaemia, anaemia; haematopoiesis with respiratory and nervous disorders; hyperthermia and weakness precede the death. This prokaryote is the first Baratonellacae found in the blood of the Giant Rat. It is namded Grahamella knaiae n. sp ("Kania" is the name of C. gambianus in "serere" language of Fatik region of Senegal). The fleas seem to be the vectors or this prokaryotic element.
D020561:Alphaproteobacteria / Q000302:isolation & purification* / Q000648:ultrastructure; D000818:Animals; D004912:Erythrocytes / Q000382:microbiology; D051381:Rats / Q000382:microbiology*; D012675:Senegal
Une rickettsiale nouvelle du rat de Gambie (Cricetomys gambianus) au Sĕnégal : Grahamella kaniae n. sp (Bartonellacae)]