A meta-analysis on global change drivers and the risk of infectious disease.

Anthropogenic change is contributing to the rise in emerging infectious diseases, which are significantly correlated with socioeconomic, environmental and ecological factors1. Studies have shown that infectious disease risk is modified by changes to biodiversity2-6, climate change7-11, chemical pollution12-14, landscape transformations15-20 and species introductions21. However, it remains unclear which global change drivers most increase disease and under what contexts. Here we amassed a dataset from the literature that contains 2,938 observations of infectious disease responses to global change drivers across 1,497 host-parasite combinations, including plant, animal and human hosts. We found that biodiversity loss, chemical pollution, climate change and introduced species are associated with increases in disease-related end points or harm, whereas urbanization is associated with decreases in disease end points. Natural biodiversity gradients, deforestation and forest fragmentation are comparatively unimportant or idiosyncratic as drivers of disease. Overall, these results are consistent across human and non-human diseases. Nevertheless, context-dependent effects of the global change drivers on disease were found to be common. The findings uncovered by this meta-analysis should help target disease management and surveillance efforts towards global change drivers that increase disease. Specifically, reducing greenhouse gas emissions, managing ecosystem health, and preventing biological invasions and biodiversity loss could help to reduce the burden of plant, animal and human diseases, especially when coupled with improvements to social and economic determinants of health.

Salmonella enterica Infection of Synanthropic Non-native Geckos in Southern Florida.

Wild geckos are a significant source of human salmonellosis. We swabbed the cloacas of 37 non-native synanthropic geckos (Gekko gecko, n = 16; Phelsuma grandis, n = 21) from southern Florida, USA, and assayed swab DNA extracts using quantitative polymerase chain reaction of the invA gene. Salmonella enterica was detected in both species with a pooled prevalence of 13.5% (5/37; 95% CI 5.3-27.1%), indicating the potential for zoonotic transmission. Implications for human health in the region are discussed.

Bridging the Research Gap between Live Collections in Zoos and Preserved Collections in Natural History Museums.

Zoos and natural history museums are both collections-based institutions with important missions in biodiversity research and education. Animals in zoos are a repository and living record of the world's biodiversity, whereas natural history museums are a permanent historical record of snapshots of biodiversity in time. Surprisingly, despite significant overlap in institutional missions, formal partnerships between these institution types are infrequent. Life history information, pedigrees, and medical records maintained at zoos should be seen as complementary to historical records of morphology, genetics, and distribution kept at museums. Through examining both institution types, we synthesize the benefits and challenges of cross-institutional exchanges and propose actions to increase the dialog between zoos and museums. With a growing recognition of the importance of collections to the advancement of scientific research and discovery, a transformational impact could be made with long-term investments in connecting the institutions that are caretakers of living and preserved animals.

Transcriptomics reveal immune downregulation of newts overwhelmed by chytrid co-infection.

What happens when two emergent diseases infect the same host? In a From the Cover article in this issue of Molecular Ecology, McDonald et al. (2020) compare transcriptomic responses to co-infection by the two chytrid fungi in the skin, liver and spleen of Eastern newts (Notophthalmus viridescens). Novel molecular tools, such as high-throughput DNA sequencing for genome discovery and transcriptomics, have revolutionized our understanding of host-pathogen interactions and disease ecology (Güimil et al. 2005; Rosenblum et al. 2012). For example, epidemiologists are using genomic data to track the spread of the emergent SARS-CoV-2 in real time, both locally and globally. RNA sequencing (RNA-Seq) is routinely employed to study response to disease in humans, improving disease diagnostics, profiling and development of intervention strategies. Transcriptomic profiles may be particularly informative for emergent diseases, whose pathologies and effect on host phenotype are poorly known. Fungal pathogens increasingly threaten a variety of wild and domesticated organisms (Fisher et al. 2012), and two chytrid fungi attacking amphibians are causing one of the worst losses of vertebrate biodiversity ever recorded (Scheele et al. 2019).

Widespread occurrence of the antifungal cutaneous bacterium Janthinobacterium lividum on Andean water frogs threatened by fungal disease.

Amphibian diversity has declined due to the infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Coexistence between amphibian hosts and this pathogen in some locations is attributed to the presence of the cutaneous bacterium Janthinobacterium lividum (Jliv). This microbe inhibits the growth of Bd on the host, reduces morbidity, and improves survival. Andean water frogs in the genus Telmatobius seem to be particularly vulnerable to the disease yet populations of T. intermedius and T. marmoratus persist in southern and central Peru. We investigated the presence of Jliv on these 2 frog species and assessed the relationship of Jliv presence with prevalence and intensity of Bd infection. By sampling 125 frogs from 7 streams (3323-3950 m a.s.l.) and 27 from a city market, we found spatial variation in the mutualism among populations (range 0-40% proportion of Jliv-positives). Overall, 57% of frogs were infected with Bd, 12.5% of frogs hosted both Jliv and Bd, while 7.2% hosted just Jliv. We found that the probability of an individual being infected with Bd was independent of the presence of Jliv; however, we did detect a protective effect of Jliv with respect to intensity of infection. The extent of Jliv distribution in the high Andes stands in stark contrast to the rarity of Jliv on frogs in lower elevation cloud forest biomes.

Bryophryne phuyuhampatu sp. n., a new species of Cusco Andes frog from the cloud forest of the eastern slopes of the Peruvian Andes (Amphibia, Anura, Craugastoridae).

A new species of Bryophryne from the humid montane forest of the Department of Cusco, Peru, is described. Specimens were collected at 2795-2850 m a.s.l. in the Área de Conservación Privada Ukumari Llaqta, Quispillomayo valley, in the province of Paucartambo. The new species is readily distinguished from all other species of Bryophryne by having green coloration on dorsum, and blue flecks on flanks and ventral parts. Specimens are characterized by lacking a distinct tympanic annulus, tympanic membrane, and dentigerous processes of vomers, and by having dorsal skin shagreen, discontinuous dorsolateral folds, skin tuberculate on flanks, skin areolate on ventral surfaces of the body, and fingers and toes without lateral fringes or webbing. The new species has a snout-vent length of 14.2-16.9 mm in three males and 22.2-22.6 mm in two females, and is smaller than all other congeneric species except for B. abramalagae. Generic allocation is supported by low genetic distances of the 16S mitochondrial gene and morphological similarity with other species of Bryophryne, and geographic distribution. Bryophryne phuyuhampatusp. n. is only known from the type locality, a cloud forest along the Quispillomayo River in the upper Nusiniscato watershed.

ResumenSe describe una nueva especie de Bryophryne de los bosques nublados del Departamento de Cusco en Perú. Los especímenes fueron colectados a una elevación de 2795­2850 m en el Área de Conservación Privada Ukumari Llaqta, valle del río Quispillomayo, provincia de Paucartambo. La nueva especie se diferencia fácilmente de todas las demás especies de Bryophryne por tener coloración verde en la espalda y manchitas azuladas en los flancos y las superficies ventrales. Los especímenes se caracterizan por carecer de procesos vomerianos y de anillo y membrana timpánicos, y por poseer piel dorsal finamente granulada, pliegues dorsolaterales discontinuos, piel en los flancos verrugosa, y cubierta de verrugas en areola en las partes ventrales, y por carecer de membrana basal y quillas laterales en los dedos. La nueva especie tiene una longitud hocico­cloaca (LHC) de 14.2­16.9 mm en tres machos y de 22.2­22.6 mm en dos hembras, siendo menor que todas las demás especies de Bryophryne excepto por B. abramalagae. Distancias genéticas bajas para el gen mitocondrial 16S, similitud morfológica con otras especies de Bryophryne y distribución geográfica indican que la nueva especie forma parte del género Bryophryne. Bryophryne phuyuhampatusp. n. se conoce únicamente de su localidad tipo, un bosque nublado en el valle del torrente Quispillomayo, en la parte alta de la cuenca del río Nusiniscato.

Batrachochytrium salamandrivorans and the Risk of a Second Amphibian Pandemic.

Amphibians are experiencing devastating population declines globally. A major driver is chytridiomycosis, an emerging infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Bd was described in 1999 and has been linked with declines since the 1970s, while Bsal is a more recently discovered pathogen that was described in 2013. It is hypothesized that Bsal originated in Asia and spread via international trade to Europe, where it has been linked to salamander die-offs. Trade in live amphibians thus represents a significant threat to global biodiversity in amphibians. We review the current state of knowledge regarding Bsal and describe the risk of Bsal spread. We discuss regional responses to Bsal and barriers that impede a rapid, coordinated global effort. The discovery of a second deadly emerging chytrid fungal pathogen in amphibians poses an opportunity for scientists, conservationists, and governments to improve global biosecurity and further protect humans and wildlife from a growing number of emerging infectious diseases.

Survey of Pathogenic Chytrid Fungi (Batrachochytrium dendrobatidis and B. salamandrivorans) in Salamanders from Three Mountain Ranges in Europe and the Americas.

Batrachochytrium salamandrivorans (Bsal) is a virulent fungal pathogen that infects salamanders. It is implicated in the recent collapse of several populations of fire salamanders in Europe. This pathogen seems much like that of its sister species, Batrachochytrium dendrobatidis (Bd), the agent responsible for anuran extinctions and extirpations worldwide, and is considered to be an emerging global threat to salamander communities. Bsal thrives at temperatures found in many mountainous regions rich in salamander species; because of this, we have screened specimens of salamanders representing 17 species inhabiting mountain ranges in three continents: The Smoky Mountains, the Swiss Alps, and the Peruvian Andes. We screened 509 salamanders, with 192 representing New World salamanders that were never tested for Bsal previously. Bsal was not detected, and Bd was mostly present at low prevalence except for one site in the Andes.

A new species of Pristimantis (Amphibia, Anura, Craugastoridae) from the foothills of the Andes in Manu National Park, southeastern Peru.

We describe a new species of Pristimantis from the humid sub-montane forest of the Región Cusco in Peru. Pristimantis pluvialis sp. n. was collected in the Kosñipata and Entoro valleys at elevations from 740 to 1110 m a.s.l., near the borders of Manu National Park and within the Huachiperi Haramba Queros Conservation Concession. The new species can be distinguished from other members of the genus Pristimantis by its rostral tubercle, smooth dorsal skin, and by its advertisement call. Pristimantis lacrimosus and Pristimantis waoranii superficially most resemble the new species, but Pristimantis pluvialis sp. n. differs from both species by having a rostral tubercle (absent in Pristimantis waoranii and variable in Pristimantis lacrimosus) and larger size, from Pristimantis lacrimosus by its call emitted at a lower frequency, and from Pristimantis waoranii for its dorsal coloration with dark markings. Two other species have partially overlapping distributions and resemble the new species, Pristimantis mendax and Pristimantis olivaceus, but they produce advertisement calls with much higher dominant frequencies than the advertisement call of the new species. Furthermore, Pristimantis mendax differs from the new species by lacking a rostral tubercle and by having a sigmoid inner tarsal fold, whereas Pristimantis olivaceus differs by being smaller and by having dorsal skin shagreen with scattered tubercles. The new species has snout-vent length of 21.8-26.9 mm in males (n = 12) and 28.8 mm in a single female.

ResumenDescribimos una nueva especie de Pristimantis de los bosques sub-montanos de la Región Cusco, en Perú. Pristimantis pluvialissp. n. fue colectada en los valles de Kosñipata y Entoro a altitudes entre 740 y 1110 m.s.n.m., cerca del límite del Parque Nacional del Manu y dentro de la Concesión para Conservación Huachiperi Haramba Queros. La nueva especie se diferencia de otros miembros del género Pristimantis por su tubérculo rostral, piel dorsal lisa, y por su canto de anuncio. Superficialmente, Pristimantis lacrimosus y Pristimantis waoranii se asemejan a la nueva especie, pero Pristimantis pluvialissp. n. difiere de ambas por tener un tubérculo dorsal (ausente en Pristimantis waoranii y variable en Pristimantis lacrimosus) y mayor tamaño; además, se diferencia de Pristimantis lacrimosus por tener un canto de anuncio producido a frecuencias más bajas, y de Pristimantis waoranii por su coloración dorsal con manchas oscuras. Dos especies con distribución parcialmente simpátrica se asemejan morfológicamente a la nueva especie, Pristimantis mendax y Pristimantis olivaceus. Ambas especies producen cantos de anuncio a frecuencias mucho más altas que la nueva especie. Además, Pristimantis mendax se distingue de Pristimantis pluvialissp. n. por carecer de tubérculo rostral y por tener un pliegue tarsal interno sigmoideo, mientras que Pristimantis olivaceus se distingue por su menor tamaño, y por tener piel finamente granular con algunos tubérculos diseminados en la parte dorsal. La nueva especie tiene una longitud hocico-cloaca de 21.8­26.9 mm en machos (n = 12) y de 28.8 mm en una hembra.