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

Assessing population trends and their underlying factors is critical to propose efficient conservation actions. This assessment can be particularly challenging when dealing with highly mobile, shy and nocturnal animals such as flying-foxes. Here we investigated the dynamics of hunted populations of Pteropus ornatus and P. tonganus in the Northern Province of New Caledonia. First, an ethno-ecological survey involving 219 local experts identified 494 flying-fox roosts. Current status was assessed for 379 of them, among which 125 were no longer occupied, representing a loss of 33% over ca. 40 years. Second, species-specific counts conducted at 35 roosts, and a sample of animals killed by hunters, revealed that the endemic species, P. ornatus, was dominant (68.5%). Between 2010 and 2016, 30 roosts were counted annually during the pre-parturition period. Roosts size averaged 1,425 ± 2,151 individuals (N = 180 counts) and showed high among-year variations (roost-specific CV = 37–162%). If we recorded significant inter-annual variation, we did not detect a significant decline over the 7-yr period, although one roost went possibly extinct. Population size of the two species combined was estimated at 338,000−859,000 individuals distributed over ca. 400 roosts in the Northern Province. Flying-foxes are popular game species and constitute traditional food for all communities of New Caledonia. Annual bags derived from a food survey allowed us to estimate harvesting rates at 5–14%. Such a level of harvesting for species with a ‘slow’ demography, the occurrence of poaching and illegal trade, suggest the current species use might not be sustainable and further investigations are critically needed.

Leptospirosis is a bacterial zoonosis that occurs in tropical and subtropical regions worldwide. Chiroptera are known to be a formidable reservoir of zoonotic pathogens, including leptospires. The epidemiology of leptospirosis in bats in the Pacific Islands is poorly known, both in terms of prevalence and in terms of the bacterial strains involved. A strong host specificity between leptospiral strains and their mammalian reservoir is recognized. This phenomenon has notably been studied recently in bat communities, providing strong evidence of co‐evolution. In New Caledonia, a biodiversity hotspot where leptospirosis is endemic and enzootic, Chiroptera are the only indigenous terrestrial mammals. In this study, we aimed to investigate leptospires associated with three flying fox species in New Caledonia. Kidneys and urine samples of Pteropus spp. from captures and seizures were analysed. Among 254 flying foxes analysed, 24 harboured pathogenic leptospires corresponding to an observed prevalence of 9.45% with 15.8% on the Main Island and 4.3% on Loyalty Islands. The analysis of the rrs gene, lfb1, and MLST sequences evidenced four distinct clusters of undescribed strains, likely corresponding to undescribed species. All four strains belong to the Group I of pathogenic Leptospira spp., which includes Leptospira interrogans, Leptospira noguchii, and Leptospira kirschneri. We detected pathogenic leptospires in all three Pteropus spp. studied (including two endemic species) with no evidence of host specificity in two co‐roosting species. For a better understanding of Leptospira–host co‐evolution, notably to genetically characterize and evaluate the virulence of these original bat‐associated leptospires, it is essential to improve isolation techniques. Flying foxes are traditionally hunted and eaten in New Caledonia, a massive cause of bat–human interactions. Our results should encourage vigilance during these contacts to limit the spillover risk of these pathogens to humans.

Hunting is a major threat to many species of wildlife. However, managing hunting systems to ensure their sustainability requires a thorough demographic knowledge about the impact of hunting. Here we develop a framework integrating ecological, modelling and sociological data to achieve a sustainability assessment of flying-fox hunting in New Caledonia and assess the relative merits of alternative management policies. Using agespecific stochastic population models, we found that the current annual hunting rate [5.5-8.5%] is likely to lead to a severe decline (-79%) of Pteropus populations over the next 30 years. However, a majority of hunters surveyed (60%) were willing to soften their practices, offering an opportunity for adaptive management. Recurrent temporary hunting ban (at least 1 year out of 2) in combination with protected areas (C 25%) appears as the most effective and most accepted management option. Our integrative approach appears to be a promising method for ensuring that traditional hunting systems can remain sustainable in a rapidly changing world.

This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence CC BY NC SA 4.0.