The aim of this study was to evaluate the prevalence of Leishmania infantum infection within a feline population by serologic and molecular methods and to identify associated risk factors. One hundred five cats living outdoors were studied. Sera were tested for IgG antibodies against L. infantum, Toxoplasma gondii, and feline immunodeficiency virus (FIV) and for the detection of feline leukemia virus (FeLV) p27 antigen by enzyme-linked immunosorbent assay (ELISA). L. infantum real-time polymerase chain reaction (PCR) was performed on DNA extracted from blood. L. infantum and T. gondii seroprevalence rates were 13.2% and 55.2%, respectively. The prevalence of L. infantum by PCR was 8.7%. The total rate of L. infantum infection derived from seroreactivity and/or positive PCR was 15.4%. Serology and PCR results were positively associated, and moderate agreement (kappa = 0.489) was found between Leishmania ELISA and PCR. No statistical association was found between positive Leishmania PCR results and gender, clinical status, or T. gondii seropositivity. Six of the 105 cats (5.7%) displayed clinical signs compatible with feline cutaneous leishmaniosis, and 4 out of these 6 cats (66.7%) were found to have Leishmania infection by means of serology and/or PCR. Leishmania seropositivity was associated with clinical signs of feline cutaneous leishmaniosis (p = 0.029). The prevalence of FeLV p27 antigen was 16.2% (17/105) and of FIV antibody was 20.9% (22/105), with coinfection found in 9.5% (10/105) of the cats. Leishmania ELISA seroreactivity and positive PCR results were statistically associated with FeLV infection and with coinfection of both retroviruses but not with a positive FIV status. The high seroprevalence and molecular rates of Leishmania infection observed indicate that cats are frequently infected with L. infantum, and the association with FeLV suggests a potential role for this retrovirus in feline Leishmania infection in endemic areas.

No abstract

The changes effected by injection of an extract of phospholipids obtained from the plasma of normal human donors (PLE) or an emulsion of commercially available sphingolipids on erythropoiesis in the mouse were studied. The parameters followed were 59Fe uptake by the erythroid tissue and the number of circulating reticulocytes. It was found that in the 12--24-h period following administration of PLE or purified sphingomyelin a significant increase in 59Fe uptake by circulating RBC an by their hemic fraction takes place. This change was associated with a higher 59Fe utilization by the bone marrow and with an increase in the number of circulating reticulocytes.

Removal of 15% of blood volume in the mouse increases erythropoiesis by a factor of 2.2 when measured 12 h after bleeding. Exposure of normal mice to 40% reduced barometric pressure for the same period of time increases erythropoiesis only by a factor of 1.6. The response to hypoxia takes place in the presence of a 40% reduction of oxygen consumption and tissue-venous PO2, changes which are concomitant with a 5-fold increase in plasma erythropoietin activity. The larger response in anemic animals on the other hand occurs without any detectable change in these parameters. These results cast serious doubts about the interpretation of the quantitative homeostatic control of erythropoiesis based solely on the action of erythropoietin.