First report of autochthonous non-vectorial canine leishmaniasis in New Caledonia, south-western Pacific: implications for new control measures and recommendations on importation of dogs.

BACKGROUND: Canine leishmaniasis (CanL), a parasitic zoonotic disease caused by Leishmania infantum and usually transmitted by phlebotomine sandflies, has rarely been reported in Pacific islands, which have been regarded until now as leishmaniasis-free territory. Here, we report the first autochthonous CanL case in New Caledonia (south-western Pacific) and the investigations carried out 1) to determine how infection was introduced into and transmitted among these dogs and 2) to assess the risks to animal and public health. METHODS: Extensive epidemiological and entomological investigations in and around the focus were carried out. Leishmaniasis infection was confirmed by histopathology, indirect fluorescent antibody test, real-time PCR, and culture. Parasite strain was typed by the isoenzymatic technique. RESULTS: The survey revealed close contacts between the autochthonous dog and two infected bitches imported from Spain, but failed to find any possible vector or disease spreading to other animals or humans. L. infantum zymodeme MON-1, the most frequent type in the Mediterranean basin, was identified. Although transplacental and venereal transmissions could not be excluded, the evidence was in favour of non-vectorial, direct dog-to-dog transmission. CONCLUSIONS: This study corroborates the possibility of non-vectorial routes (transplacental, venereal, and direct dog-to-dog) of canine leishmaniasis transmission in New Caledonia and raises the debate of relevant test requirements and diagnostic sensitivity prior to importation of dogs in Leishmania-free regions. New leishmaniasis control measures and recommendations to avoid future CanL introduction on the island are discussed.

Muscle satellite cell heterogeneity: in vitro and in vivo evidences for populations that fuse differently.

During development, muscle growth results from the proliferation of satellite cells (SC) and their fusion with fibers. Several studies revealed heterogeneity of SC population notably based on the proliferation rate. Here, we examined the SC characteristics of turkey skeletal muscles in terms of proliferation and more specifically fusion, to define if the ability of these cells to fuse may represent a distinct characteristic between them and could be directly associated with their proliferation properties. Freshly extracted SC were plated in clonal condition and their proliferation rate was assessed 11 days later. To investigate the SC fusion behavior, in vitro and in vivo approaches were developed. Highly and slowly proliferative SC were initially labeled with a nuclear beta-galactosidase (beta-Gal) activity and co-cultured with differentiated primary cultures. After 5 days, distribution of beta-Gal positive (beta-Gal+) nuclei was examined. Also, the two labeled SC types were transplanted into different muscles in autologous model. One week later, number of beta-Gal+ nuclei per fiber and diameter of fibers displaying beta-Gal+ nuclei were determined. In vitro, we showed that SC from turkey skeletal muscle are present as a heterogeneous population in terms of proliferation. Examination of their fusion properties in vitro as well as in vivo revealed that highly proliferative SC exclusively exhibited fusion with differentiated myotubes or myofibers, whereas slowly proliferative SC mainly fused together. Collectively, these data demonstrate for the first time that SC with different proliferation rate also intrinsically differ in their fusion potential, suggesting distinct roles for these sub-populations in muscle growth.