Interdisciplinary approach to solve unusual mortalities in the European common frog (Rana temporaria) in two high-mountain ponds affected by climate change.

The global decline in amphibian populations is a major environmental issue. Chytridiomycosis, Ranaviruses and the red-leg syndrome have been identified in unusual mortality events. However, these infections do not account for all causes of declining amphibian populations. Moreover, several cases of amphibian mortality are difficult to solve without resorting to an interdisciplinary approach. Two cases of unusual mortality in Rana temporaria occurred at two high-mountain ponds (northwest Italy) in April and May 2021. Water and frog samples were analysed to understand the possible causes responsible for the unusual mortalities. Results of the main physicochemical (pH, conductivity, dissolved oxygen, chemical and biochemical oxygen demand) and nutrient (ammonia/ammonium, nitrite, nitrate, total phosphorus) parameters revealed a good condition of the water quality, with the absence of the main cyanotoxins (microcystins/nodularins). However, unseasonably high spring water temperatures were recorded in both ponds (12.73 °C and 14.21 °C for Frog Pond and Selleries Pond, respectively). Frogs (n = 50; snout-vent length: 7.0-9.8 cm; body mass: 85-123 g) collected from Frog Pond mainly presented bumps on the ventral cavity and dermal ulceration associated with the isolation of Carnobacterium maltaromaticum. On the other hand, frogs (n = 5; snout-vent length: 8.0-9.1 cm; body mass: 87-92 g) from Selleries Pond presented petechiae and dermal ulcerations on the rear limbs associated with the isolation of Aeromonas salmonicida and A. sobria. In both mortality events, the interdisciplinary approach revealed an association between frog mortalities and the isolation of bacteria. Isolated bacteria are considered opportunistic pathogens, and the high values of the water temperature has certainly led a stress on the frogs, favouring the spread of bacteria and the death of the frogs. Further studies are needed to assess the pathophysiological effects of the opportunistic bacteria here isolated, clarifying the interactions between emerging pathogens and climate change.

Factors associated with foot-and-mouth disease seroprevalence in small ruminants and identification of hot-spot areas in northern Nigeria.

Many small ruminants infected with foot-and-mouth disease (FMD) remain asymptomatic, with the capacity to promote silent viral spread within domestic and wildlife species. However, little is known about the epidemiological role played by small ruminants in FMD. In particular, there are few studies that examine FMD seroprevalence, spatial patterns and risk factors for exposure in small ruminants. A cross-sectional study was conducted in northern Nigeria (Bauchi, Kaduna, and Plateau States) to determine the true seroprevalence of FMD in backyard small ruminants, identify factors associated with FMD seroconversion at animal and household levels, and identify spatial patterns for FMD virus exposure. Data on animal (n = 1800) and household (n = 300) characteristics were collected using a standardised questionnaire. Sera samples from 1800 small ruminants were tested for antibodies against non-structural proteins of FMD virus. True seroprevalence was estimated stochastically to account for variability and uncertainty in the test sensitivity and specificity previously reported. Risk factors for FMD seropositivity were identified at animal and household levels and spatial patterns were determined. The overall true seroprevalence for FMD virus, in the small ruminant population tested, was estimated to be 10.2 % (95 % Credible Interval (CrI) 0.0-19.0), while State-level estimates were 17.3 % (95 % CrI 0.0-25.8) for Kaduna, 6.9 % (95% CrI 0.0-15.8) for Bauchi, and 3.6 % (95 % CrI 0.0-12.6) for Plateau. State and species were the main risk factors identified at animal level, with interaction detected between them. Compared to goats in Plateau, the odds of testing positive were higher for goats in Bauchi (Odds Ratio (OR)= 1.83, 95 % CI 1.13-2.97, p = 0.01) and Kaduna (OR=2.97, 95 % CI 1.89-4.67, p < 0.001), as well as for sheep in Plateau (OR=3.78, 95 % CI 2.08-6.87, p < 0.001), Bauchi (OR=1.61, 95 % CI 0.91-2.84, p = 0.10), and Kaduna (OR=3.11, 95 % CI 1.61-6.01, p = 0.001). Households located in Kaduna were more likely to have a higher number of seropositive SR compared to those in Plateau (Prevalence Ratio (PR)= 1.75, 95 % CI 1.30-2.36, p < 0.001), and households keeping sheep flocks were more likely to be seropositive (from 1 to 10 sheep: PR=1.39, 95 % CI 1.05-1.82, p = 0.02; more than 10 sheep: PR=1.55, 95 % CI 1.12-2.15, p = 0.008) compared to those that did not keep sheep. A hot-spot was detected in Kaduna, and a cold-spot in Plateau. These results reveal that small ruminants had been recently exposed to FMD virus with spatial heterogeneity across the study area.

Unintentional Recovery of Parasitic Diversity Following Restoration of Red Deer (Cervus elaphus) in North-Western Italy.

Red deer (Cervus elaphus) populations in north-western Italy have been remodeled in recent decades. Multiple translocations and the spontaneous migration from Switzerland and France resulted in the successful redistribution of the red deer after human-driven extirpation during the 18th century. The scarcely diverse parasitic community harbored by these cervids has been enriched with two species-specific taxa, Onchocerca jakutensis and Phayigomyia picta, suggesting that the recovery of parasitic biodiversity could be included amongst future conservation goals of this intensively managed game. Nodular onchocercosis was reported in three red deer populations since 2011, while nasal bots were reported since 2018. Hypoderma spp. larvae were identified for the first time in 1989, then a second record was made in 2014 in the province of Biella, where a yearling male in poor condition infested with Hypoderma diana was observed. In the perspective that the restoration of species-specific parasite communities of native mammals in Europe is increasingly perceived as a conservation target, with similar dignity as the conservation of their hosts, baseline data presented in this communication may give new insights for future parasite conservation efforts.

Endemic occurrence of Fasciola hepatica in an alpine ecosystem, Pyrenees, Northeastern Spain.

Fasciola hepatica is a liver parasite of ruminants whose distribution is determined by its intermediate host, the freshwater snail Galba truncatula. In Europe, F. hepatica is mostly associated with lowlands. Infection from sympatric domestic reservoirs is rarely reported in wild mountain ungulates. This study explores F. hepatica in a multi-host system in a European alpine area. Serum samples (n = 1,209) from Pyrenean chamois (Rupicapra p. pyrenaica), European mouflon (Ovis aries musimon), domestic sheep (Ovis aries) and domestic cattle (Bos taurus) were collected in the National Game Reserve of Freser-Setcases (NGRFS) in Catalonia, Northeastern Spain, from 2008 to 2019, and tested for antibodies against F. hepatica. During the same period, the livers of 214 chamois hunted in the NGRFS were inspected for F. hepatica and associated pathological changes. Finally, 907 freshwater snails were collected in summer 2016 between 1559 and 2,224 metres above sea level (asl) in the NGRFS, and F. hepatica DNA sought by PCR. Antibodies against F. hepatica were detected in all four species, with a higher prevalence in cattle and sheep than in chamois. Fasciola hepatica and hepatic lesions were concurrently observed in 13/214 of the chamois livers inspected (6.1%, CI95 2.9%-9.3%). Fasciola hepatica DNA was detected in one out of the 907 snails (0.1%, Cl95 0.1% - 0.3%; Ct value 33.3) and collected at 2054 m asl. Fasciola hepatica was consistently detected in a high mountain multi-host system, suggesting that its life cycle is completed and that it occurs endemically at the highest elevation reported in Europe. Transhumant livestock are the likely source in this alpine ecosystem, which according to rare occurrence of F. hepatica DNA in G. truncatula is still a suboptimal habitat for F. hepatica life cycle. Studying parasites at their highest distribution range can be useful to monitor climate change in seasonal mountain environments.

Peste des Petits Ruminants at the Wildlife-Livestock Interface in the Northern Albertine Rift and Nile Basin, East Africa.

In the recent past, peste des petits ruminants (PPR) emerged in East Africa causing outbreaks in small livestock across different countries, with evidences of spillover to wildlife. In order to understand better PPR at the wildlife-livestock interface, we investigated patterns of peste des petits ruminants virus (PPRV) exposure, disease outbreaks, and viral sequences in the northern Albertine Rift. PPRV antibodies indicated a widespread exposure in apparently healthy wildlife from South Sudan (2013) and Uganda (2015, 2017). African buffaloes and Uganda kobs <1-year-old from Queen Elizabeth National Park (2015) had antibodies against PPRV N-antigen and local serosurvey captured a subsequent spread of PPRV in livestock. Outbreaks with PPR-like syndrome in sheep and goats were recorded around the Greater Virunga Landscape in Kasese (2016), Kisoro and Kabale (2017) from western Uganda, and in North Kivu (2017) from eastern Democratic Republic of the Congo (DRC). This landscape would not be considered typical for PPR persistence as it is a mixed forest-savannah ecosystem with mostly sedentary livestock. PPRV sequences from DRC (2017) were identical to strains from Burundi (2018) and confirmed a transboundary spread of PPRV. Our results indicate an epidemiological linkage between epizootic cycles in livestock and exposure in wildlife, denoting the importance of PPR surveillance on wild artiodactyls for both conservation and eradication programs.

Mycoplasma conjunctivae in insect vectors and anatomic locations related to transmission and persistence.

Mycoplasma conjunctivae is an obligate microparasite that causes Infectious Keratoconjunctivitis (IKC) in Caprinae species. IKC is a long-recognised disease, but little attention has been paid to the mechanisms of transmission of the mycoplasma and its occurrence in locations other than the eyes. In this study, the presence of M. conjunctivae is assessed in the eyes, external ear canals (EEC), nasal cavity, and vagina of host species as well as in potential vectors, which may be involved in the transmission and persistence of infection within the host. M. conjunctivae was detected by qPCR in 7.2 % (CI 95% 4.7-11.0) of the ear swabs and 9.5 % (CI 95% 6.4-13.9) of the nasal swabs from Pyrenean chamois, Iberian ibex, domestic sheep and mouflon without statistical differences between species. Mycoplasma detection in nasal swabs was mostly associated with ocular infection (95.6%), but this was not the case for EEC (52.6%). Among the eye-positive ruminants, 27.3% were positive in ear swabs and 64.7% in nasal swabs, and the threshold cycle values of the qPCR were correlated only between eye and nasal swabs (p < 0.01; r2 = 0.56). M. conjunctivae was detected in 1.7% - 7.1 % of Musca spp. captured during an IKC outbreak in Iberian ibex and in one out of three endemic sheep flocks. The results indicate that the transmission of M. conjunctivae may occur by direct contact with eye or nasal secretions and/or indirectly through flies. The M. conjunctivae DNA detection in EEC suggests that it can colonise the auditory tract, but the significance for its persistence within the host should be further assessed.