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The ingestion of lead (Pb) shot pellets is a well-known cause of avian mortality, but exposure of birds to Pb may have other sublethal effects that can affect population sustainability. One of these effects is the alteration of the immunological status. Pb can affect most components of the avian immune system and imbalance the relationship among them. Pb exposure typically alters the ratio between T- and T-type responses mounted by different classes of T-lymphocytes, causing the depression of the T responses that are associated with cell-mediated immunity. Immunodepressing effects of Pb on birds are observed at blood levels above 50 μg dL, but developing birds show immunodepressing effects at much lower concentrations (> 10 μg dL). Impacts of Pb on the avian immune system also relate to reduced resistance to infection. We review immunotoxic effects of Pb on birds affected by shot ingestion as well as by other sources of exposure to this element., Part of the information included in this review was compiled as part of a research project funded by the Spanish Ministry of Science and Innovation (grant CGL2010-17030) and included in the PhD Thesis of NVC, who benefited from an FPI fellowship of the Spanish Ministry of Science and Innovation (ref. BES-2011-045670).

The Iberian lynx (Lynx pardinus) is one of the most endangered felid species in the world. Conservation efforts have increased its population size and distribution and reinforced their genetic diversity through captive breeding and reintroduction programmes. Among several threats that the Iberian lynx faces, infectious and parasitic diseases have underlined effects on the health of their newly reintroduced populations, being essential to identify the primary sources of these agents and assess populations health status. To achieve this, 79 fresh faecal samples from Iberian lynx and sympatric mesocarnivores were collected in the reintroduction area of Extremadura, Spain. Samples were submitted to copromicroscopic analyses to assess parasite diversity, prevalence, and mean intensity of parasite burden. Overall, 19 (24.1%, ±15.1-35.0) samples were positive for at least one enteric parasite species. Parasite diversity and prevalence were higher in the Iberian lynx (43.8%) compared with the others mesocarnivores under study (e.g., the red fox Vulpes vulpes and the Egyptian mongoose Herpestes ichneumon). Ancylostomatidae and Toxocara cati were the most prevalent (15.6%) parasites. Obtained results revealed that Iberian lynx role as predator control might have reduced parasite cross-transmission between this felid and mesocarnivores due to their decreasing abundances. Surveillance programs must include regular monitoring of this endangered felid, comprising mesocarnivores, but also domestic/feral and wild cat communities. This research was funded by the European Union through its LIFE project Life + IBERLINCE (LIFE + 10NAT/ES/570) “Recuperación de la distribución histórica del lince ibérico (Lynx pardinus) en España y Portugal”. R. T. Torres is funded by national funds (OE), through FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020 + UIDB/50017/2020) and CIISA Project UIDB/00276/2020 through national funds. Sí

The ingestion of spent lead (Pb) from ammunition is a known cause of mortality in waterfowl, but little is known about sublethal effects produced by Pb poisoning on birds, especially in wild populations. The authors studied potential sublethal effects associated with Pb exposure in mallards (Anas platyrhynchos) from the Ebro delta (northeastern Spain) after a ban on Pb ammunition. They analyzed the relationships between blood Pb levels and oxidative stress, immune response, and carotenoid-based coloration, which are known to be influenced by oxidative stress. Levels of Pb were reduced by half from 6 yr to 9 yr after the ban. Lipid peroxidation was positively related to Pb levels in females. The δ-aminolevulinic acid dehydratase activity was suppressed by Pb exposure and negatively associated with the activity of antioxidant enzymes. Carotenoid levels were positively associated with blood Pb concentration in both sexes, and males with higher Pb levels presented a less intense coloration in legs and beak. Levels of Pb were positively related to hemolytic activity of circulating immune system components and negatively related to lysozyme levels. In summary, Pb exposure was associated in a gender-specific way with increased oxidative stress, consequences on color expression, and impaired constitutive immunity. In females, antioxidants seemed to be allocated mostly in reproduction rather than in self-maintenance, whereas males seemed to better maintain oxidative balance to the detriment of coloration., Funding was provided by the Spanish Ministry of Science and Innovation (grants CGL2007-62797 and CGL2010-17030), and FPI fellowship (BES-2011-045670, to N. Vallverdu-Coll), and the Juan de la Cierva program (to M. Ortiz-Santaliestra).

Lethal interactions between members of the carnivore guild are well represented in literature. In the Iberian lynx, interspecific killing (without prey consumption) of some mesocarnivores, such as the Egyptian mongoose, genet, and red fox, has been reported. Although vaguely documented, evidence suggests feral cats fall victim to interactions with this apex predator. Here, we describe the first documented case of interspecific killing and partial consumption of a feral cat by an adult male Iberian lynx reintroduced in Southwestern Spain. Ulterior analyses demonstrated that the victim was viremic to feline leukemia virus. To prevent the dissemination of the virus and a potential outbreak in the Iberian lynx population, control measures, including the clinical evaluation of the male Iberian lynx, and intensive monitoring were implemented in order to detect intraspecific interactions. After 3 weeks, the lynx was evaluated, presented good condition and resulted negative to both ELISA and RT-PCR. Thanks to the long-term monitoring, this case could be detected and measures to prevent an outbreak could be implemented., This research was funded by the European Union through its LIFE project Life+IBERLINCE (LIFE+10NAT/ES/570) “Recuperación de la distribución histórica del lince ibérico (Lynx pardinus) en España y Portugal”.

A free-ranging Iberian lynx (Lynx pardinus) was found dead after 16 mo of being reintroduced. On gross necropsy, necrotic areas in the left biceps femoris and intercostal muscles were identified. Streptococcus canis was isolated from both groups of muscles and was confirmed by PCR, corroborating a necrotizing myositis diagnostic.

[ES]: La intoxicación por ingestión de munición de plomo en aves silvestres es conocida en España desde finales del siglo pasado. Elevadas densidades de perdigones de plomo en diversos humedales de importancia internacional producen tasas de ingestión de perdigones cercanas al 70% en especies como el ánade rabudo (Anas acuta) y el plumbismo llega a ser una de las principales causas de mortalidad de la amenazada malvasía cabeciblanca (Oxyura leucocephala). El plumbismo también ha sido descrito en diversas especies de aves rapaces y se ha comprobado que la exposición al plomo es elevada en las especies más carroñeras y oportunistas. La contaminación de la carne de caza también ha sido objeto de estudio, debido a que en España se da la particularidad de cocinarla en escabeche, lo que incrementa la transferencia de plomo de la munición a la carne. Por el momento, la única acción llevada a cabo para reducir el riesgo de exposición al plomo de la munición en aves y humanos ha sido la prohibición desde 2001 del uso de perdigones de plomo en humedales protegidos. En esta revisión se hace un repaso a los estudios llevados a cabo en España sobre la contaminación por el plomo de la munición y el efecto que están teniendo las medidas hasta el momento adoptadas para reducir este riesgo., [EN]: Poisoning by ingestion of lead ammunition in wild birds is known in Spain since the end of the last century. High densities of lead shot in various internationally important wetlands produce pellet ingestion rates close to 70% in species such as the northern pintail (Anas acuta) and lead poisoning becomes a major cause of mortality of the endangered white-headed duck (Oxyura leucocephala). Lead poisoning has also been described in several species of birds of prey, mainly scavengers. The contamination of game meat has also been studied, because in Spain it is usually cooked with vinegar, increasing the transfer of lead from ammunition to meat. For now, the only action taken to reduce the risk of exposure to lead from ammunition in birds and humans has been the banning since 2001 of lead shot in protected wetlands. Here, we review the studies carried out in Spain on lead contamination caused by the ammunition and the effect of the measures taken to reduce this risk., Esta revisión se enmarca dentro del proyecto financiado por el MICINN con referencia CGL2010-17030/BOS. NV disfruta de una beca FPI asociada a dicho proyecto. MEOS disfruta de un contrato del programa Juan de la Cierva.

Lead (Pb) poisoning via ingestion of shot pellets is a frequent cause of death in wild birds and also has a wide range of subclinical effects. Here we report on the sublethal effects Pb exposure has on the breeding performance of red-legged partridges (Alectoris rufa). We studied the effects of Pb exposure on sperm quality, reproductive success, egg properties, laying performance, antioxidant levels, and carotenoid-based coloration. Birds were exposed by oral gavage to one or three No. 6 Pb shot pellets (2.8 mm in diameter, mean mass ± SD: 109 ± 7.97 mg). We show that exposure to three pellets (330 mg) reduced the hatching rate of females and decreased the acrosome integrity and sperm motility of males. In addition, females exposed to 1 pellet (110 mg) produced heavier eggs and chicks, whereas males exposed to 1 pellet presented an increase in sperm vigor. Sperm viability, concentration, progressiveness or fecundation rate were not affected by Pb treatment. Pb exposure increased circulating antioxidant levels in males, whereas the percentage of carotenoid-pigmented eye-ring area decreased in exposed females. Several sperm parameters showed positive relationships with coloration and antioxidant levels, suggesting that males displaying redder ornaments may be more capable of protecting sperm from oxidative stress in the event of sublethal Pb exposure., This study was funded by the Spanish Ministry of Education and Science (grant CGL2010-17030). N.V.-C. was supported by an FPI scholarship funded by the Spanish Ministry of Economy and Competitiveness (BES-2011-045670).

Lead (Pb) poisoning has caused significant mortality in waterfowl populations worldwide. In spite of having been banned since 2003, prevalence of Pb shot ingestion in mallards (Anas platyrhynchos) from the Ebro delta was still 15.5% in 2011-12. We collected mallard eggs from this area to study the effects of maternally transferred Pb on eggshell properties and on immune response and oxidative balance of ducklings. Eggshell Pb levels were positively correlated with Pb levels in the blood of ducklings. Ducklings with blood Pb levels above 180 ng mL-1 showed reduced body mass and died during the first week post hatching. Blood Pb levels positively correlated with humoral immune response, endogenous antioxidants and oxidative stress biomarkers, and negatively correlated with cellular immune response. Pb shot ingestion in birds can result in maternal transfer to the offspring that can affect their developing immune system and reduce their survival in early life stages., The founding of this study was provided by the Spanish Ministry of Science and Innovation (grants CGL2007-62797 and CGL2010-17030). NVC benefits from an FPI fellowship (BES-2011-045670), MEOS was contracted under Juan de la Cierva program and MMH benefits from a Marie Curie Fellowship (PIEF-GA-2011-299747) within the 7th Framework Programme (FP7 2007–2013) of the European Commission.

Ingestion of lead (Pb) shot pellets constitutes the main cause of Pb poisoning in avifauna. We studied the effects of sublethal Pb exposure on immunity, carotenoid-based coloration, oxidative stress and trade-offs among these types of responses during spring and autumn in red-legged partridges (Alectoris rufa). We evaluated constitutive immunity testing lysozyme and natural antibody levels, and blood bactericidal and phagocytic activities. We studied induced immunity by testing PHA and humoral responses. We analyzed fecal parasite and bacterial abundance and oxidative stress biomarkers. Pb exposure in spring reduced natural antibody levels, whereas in autumn, it reduced lysozyme levels and increased phagocytic activity. Pb exposure increased PHA response in both seasons, and decreased T-independent humoral response in autumn. Pb exposure also increased noncoliform and decreased coliform Gram-negative gut bacteria. In spring, Pb exposure decreased antioxidant levels and increased coloration in males, whereas in autumn, it increased retinol levels but reduced coloration in both genders. Our results suggest that in spring, Pb-exposed females used antioxidants to cope with oxidative stress at the expense of coloration, whereas Pb-exposed males increased coloration, which may reflect an increased breeding investment. In autumn, both genders prioritized oxidative balance maintenance at the expense of coloration., This study was funded by the Spanish Ministry of Education and Science (grant CGL2010-17030). Nuria Vallverdu-Coll was supported by an FPI scholarship funded by the Spanish Ministry of Economy and Competitiveness (BES-2011-045670).

The use of lead (Pb) ammunition in the form of shot pellets has been identified as a Pb exposure risk in wildlife and their human consumers. We explore the hypothesis that Pb shot ban enforcement reduces the risk of avian Pb poisoning as well as Pb exposure in game meat consumers. We assessed compliance with a partial ban on Pb shot commencing in 2003 by examination of 937 waterbirds harvested by hunters between 2007 and 2012 in the Ebro delta (Spain). Prevalence of Pb shot ingestion was determined, as were Pb concentrations in liver and muscle tissue to evaluate the potential for Pb exposure in game meat consumers. Hunted birds with only embedded Pb shot (no steel) declined from 26.9% in 2007-08 to, This study was supported by the Spanish Ministry of Science and Innovation (grants CGL2007-62797 and CGL2010-17030). NVC benefits from an FPI Fellowship (BES-2011-045670), MAT and MEOS were contracted under the Juan de la Cierva program and MMH benefits from a Marie Curie Fellowship (PIEF-GA-2011-299747).