Background Hemotropic mycoplasmas, previously classified in the genus Eperythrozoon, have been reported as causing human infections in Brazil, China, Japan and Spain. Methods In 2017, we detected DNA from “Candidatus Mycoplasma haemohominis” in the blood of a Melanesian patient from New Caledonia presenting with febrile splenomegaly,weight loss, life-threatening autoimmune haemolytic anemia and hemophagocytosis. The full genome of the bacterium was sequenced from a blood isolate. Subsequently, we tested retrospectively (2011-2017) and prospectively (2018-2019) patients who had been hospitalized with a similar clinico-biological picture. In addition, as these patients had been in contact with frugivorous bats (authorized under conditions for hunting and eating in New Caledonia) we investigated the role of these animals and their biting flies by testing them for hemotropic mycoplasmas. Results Fifteen patients were found to be infected by this hemotropic mycoplasma. Among them, four (27%) died following splenectomy performed for spontaneous spleen rupture, or to cure refractory autoimmune haemolytic anemia. The bacterium was cultivated from the patient's blood. The full genome of the Neocaledonian “Candidatus M. haemohominis” strain differed from that of a recently identified Japanese strain. Forty-six percent of 40 tested Pteropus bats and 100% of collected bat flies Cyclopodia horsfieldi (Nycteribiidae, Diptera) were positive. Human,bat and dipteran strains were highly similar. Conclusions The bacterium being widely distributed in bats, “Candidatus M. haemohominis” should be regarded as a potential cause of severe infections in humans.

Invasive feral cats threaten biodiversity at a global scale. Mitigating feral cat impacts and reducing their populations has therefore become a global conservation priority, especially on islands housing high endemic biodiversity. The New Caledonian archipelago is a biodiversity hotspot showing outstanding terrestrial species richness and endemism. Feral cats prey upon at least 44 of its native vertebrate species, 20 of which are IUCN Red-listed threatened species. To test the feasibility and efficiency of culling, intensive culling was conducted in a peninsula of New Caledonia (25.6 km²) identified as a priority site for feral cat management. Live-trapping over 38 days on a 10.6 km² area extirpated 36 adult cats, an estimated 44% of the population. However, three months after culling, all indicators derived from camera-trapping (e.g., abundance, minimum number of individuals and densities) suggest a return to pre-culling levels. Compensatory immigration appears to explain this unexpectedly rapid population recovery in a semi-isolated context. Since culling success does not guarantee a long-term effect, complementary methods like fencing and innovative automated traps need to be used, in accordance with predation thresholds identified through modelling, to preserve island biodiversity. Testing general assumptions on cat management, this article contributes important insights into a challenging conservation issue for islands and biodiversity hotspots worldwide.

1. Cats Felis catus, in all their forms (domestic, free-roaming/stray and feral), have been identified as a major global threat to biodiversity, especially birds and small mammals. However, there has been little previous consideration of the extent and impact of predation of bats by cats, or of whether specific characteristics make certain species of bats particularly vulnerable to predation by cats. 2. We reviewed the impact of cats on bats, based on a collation of scientific literature and the International Union for Conservation of Nature (IUCN) Red List database. Our aim was to produce a synthesis of the extent to which cats prey upon and threaten bats. We also collated available data on cat diet, which provide information on predation rates of bats by cats. 3. Few studies (n = 44) have identified bat species preyed upon or threatened by cats, with a disproportionate number of studies from islands. In these studies, 86 bat species (about 7% of the global extant tally) are reported as preyed upon or threatened by cats, and about one quarter of these species are listed as Near Threatened or threatened (IUCN categories Critically Mammal Review