Tuberculosis in Wild Pigs from Argentina.

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTC) and non-tuberculous Mycobacteria (NTM), may infect wild and domestic mammals, including humans. Although cattle are the main hosts and spreaders of M. bovis, many wildlife hosts play an important role worldwide. In Argentina, wild boar and domestic pigs are considered important links in mammalian tuberculosis (mTB) transmission. The aim of this work was to investigate the presence of M. bovis in wild pigs from different regions of Argentina, to characterize isolates of M. bovis obtained, and to compare those with other previously found in vertebrate hosts. A total of 311 samples from wild pigs were obtained, and bacteriological culture, molecular identification and genotyping were performed, obtaining 63 isolates (34 MTC and 29 NTM). Twelve M. bovis spoligotypes were detected. Our findings suggest that wild pigs have a prominent role as reservoirs of mTB in Argentina, based on an estimated prevalence of 11.2 ± 1.8% (95% CI 8.0-14.8) for MTC and the frequency distribution of spoligotypes shared by cattle (75%), domestic pigs (58%) and wildlife (50%). Argentina has a typical scenario where cattle and pigs are farm-raised extensively, sharing the environment with wildlife, creating conditions for effective transmission of mTB in the wildlife-livestock-human interface.

A multispecies competitive nanobody-based ELISA for the detection of antibodies against hepatitis E virus.

The hepatitis E virus (HEV) is an emergent zoonotic virus causing viral hepatitis worldwide. Clinically, hepatitis E is not easily distinguished from other types of acute viral hepatitis. There is a need for HEV diagnostic assays to detect and prevent interspecies transmission among susceptible populations. Nanobodies (Nbs) are expressed recombinantly in different systems, produced with high yields, and have superior physicochemical properties compared with conventional antibodies (Ab). Several Nbs against ORF2, the capsid protein and main antigen, were selected and produced in E. coli. Nb39 and Nb74 specifically recognized HEV ORF2 (genotypes 3 and 4). A competitive ELISA (cELISA) was developed and validated using a reference panel of human (n = 86) and swine sera (n = 116) tested in comparison with a commercial kit. The optimal cutoff values determined by ROC analysis were 69.16% (human) and 58.76% (swine); the sensitivity and specificity were high: 97.4% (95% CI 86.5-99.5%) and 95.8% (95% CI 86.0-98.8%) for human vs. 100% (95% CI 93.5-100%) and 98.3% (95% CI 91.0-99.7%) for swine. Further, the cELISA detected total anti-HEV antibodies in wild boar, deer, and mice. To our knowledge, this is the first report of production of Nbs against HEV-3 ORF2 for diagnostic purposes.

Lead exposure in dogs fed game meat and offal from culled invasive species in El Palmar National Park, Argentina.

This is the first field study to evaluate lead exposure in dogs fed game meat and offal and, to our knowledge, the first study exploring associations between game consumption and dog health status. We quantified lead concentrations in blood and hair and haematological parameters of 31 dogs fed game meat and offal from wild boar (Sus scrofa) and axis deer (Axis axis) culled with lead ammunition in El Palmar National Park, Argentina. Despite variable weekly frequency in game consumption, dogs had detectable blood and hair lead levels, demonstrating recent and chronic exposure. Lead geometric mean and SD were 18.91 ± 346.85 µg/dL w.w. in blood (range = 0.53-216.58), and 0.721 ± 6.444 µg/gr d.w. in hair (range = 0.007-34.800). Hair lead levels were relatively low in most samples, except for the oldest dog which had an atypically high value concurrent with anaemia, a common outcome of chronic lead exposure. Dog's owner was significantly predictive of both blood and hair lead levels, which reflects the same feeding patterns for all dogs owned by the same person. Body condition was associated with hair lead, with dogs in good condition presenting higher lead levels. This could be related to greater game consumption by those dogs, resulting in higher lead ingestion. Dogs fed game meat and offal at very low or low frequency (≤4 times per week) showed higher blood lead levels, suggesting there might not be a risk-free frequency for game provision to dogs. Considering the risks of dietary lead exposure, avoiding feeding dogs lead-killed game and replacing lead ammunition with non-toxic alternatives are recommended. This would allow using hunted game as a valuable food resource without unnecessary risk for the health of consumers and the environment.

Lead exposure in consumers of culled invasive alien mammals in El Palmar National Park, Argentina.

Consumption of meat from animals hunted with Pb ammunition can cause toxic accumulation with consequent health risks, even if relatively small amounts are consumed in each exposure. In El Palmar National Park, Argentina, invasive alien mammals, wild boar (Sus scrofa) and axis deer (Axis axis), are culled with Pb ammunition and their meat is consumed. In this study, we evaluated blood Pb concentrations in 58 consumers of culled game and examined Pb exposure risk according to their demographics, duty, and consumption habits. Likewise, the likelihood of exposure was evaluated by quantifying Pb concentrations in meat samples of seven culled axis deer. Twenty-seven participants (46%) had detectable blood Pb levels (limit of detection = 3.3 µg/dL), with an average 4.75 ± 1.35 µg/dL (geometric mean ± geometric S.D.); the average for all participants was 3.25 ± 1.51 µg/dL. Blood Pb concentrations were significantly higher in hunters, in participants who reported consuming game meat more than 5 times per week, and in participants who reported frequently consuming cured game meat (compared to cooked or pickled). Pb concentration varied significantly along the trajectory of the bullet in deer muscle, being highest at mid-point but with detectable Pb levels even in distant tissue samples (control), suggesting potential for dietary intake by consumers. These findings provide evidence of Pb exposure risk in consumers and emphasize the relevance of replacing Pb ammunition with non-toxic alternatives. This change would reduce dietary exposure in frequent consumers and allow the use of game meat as safe food for people whilst eliminating collateral risks to wild animals and the environment.