Victims or vectors: a survey of marine vertebrate zoonoses from coastal waters of the Northwest Atlantic

Abstract

Surveillance of zoonotic pathogens in marine birds and mammals in the Northwest Atlantic revealed a diversity of zoonotic agents. We found amplicons to sequences from Brucella spp., Leptospira spp., Giardia spp. and Cryptosporidium spp. in both marine mammals and birds. Avian influenza was detected in a harp seal and a herring gull. Routine aerobic and anaerobic culture showed a broad range of bacteria resistant to multiple antibiotics. Of 1460 isolates, 797 were tested for resistance, and 468 were resistant to one or more anti-microbials. 73% (341/468) were resistant to 1–4 drugs and 27% (128/468) resistant to 5–13 drugs. The high prevalence of resistance suggests that many of these isolates could have been acquired from medical and agricultural sources and inter-microbial gene transfer. Combining birds and mammals, 45% (63/141) of stranded and 8% (2/26) of by-caught animals in this study exhibited histopathological and/or gross pathological findings associated with the presence of these pathogens. Our findings indicate that marine mammals and birds in the Northwest Atlantic are reservoirs for potentially zoonotic pathogens, which they may transmit to beach goers, fishermen and wildlife health personnel. Conversely, zoonotic pathogens found in marine vertebrates may have been acquired via contamination of coastal waters by sewage, run-off and agricultural and medical waste. In either case these animals are not limited by political boundaries and are therefore important indicators of regional and global ocean health.

Avian Influenza Virus Infection Dynamics in Shorebird Hosts

“…Given that a majority of Ruddy Turnstones were exposed to AIV over the stopover season and that Laughing Gulls and turnstones share multiple habitats in the Delaware Bay area (data not shown), it is not surprising that many Laughing Gulls also were exposed. To date, Laughing Gulls have not been extensively sampled at Delaware Bay or elsewhere (reviewed by Bogomolni et al, 2008) and infection data are limited in this study. More systematic sampling of Laughing Gulls including time periods before shorebird arrival and after their departure would help to characterize AIV dynamics in this species further.…”

Dynamics of Vibrio with Virulence Genes Detected in Pacific Harbor Seals (Phoca vitulina richardii) Off California: Implications for Marine Mammal Health

“…Current knowledge of the diversity and ecology of marine pathogens in harbor seals is limited to clinical cases, serological surveys, zoonotic cases (marine mammal caretakers), and epidemics associated with animal-stranding events [10,37,38,73,78,83,92]. The most common cause of live harbor seal strandings in central California during the last ten years was malnutrition (52%) [16].…”

“…Cumulative effects of one or more of these factors may have contributed to the deterioration of marine mammal health [10,11,13,35]. Because infectious marine diseases appear to be increasing and are of immediate concern to marine mammal health, the dynamics and virulence potential of aquatic microbes should be investigated [4,10,28,38,48,75].…”

“…Baseline epidemiological data on marine pathogens can be obtained from a representative marine mammal to aid in disease mitigation in marine mammals [10,36,48,65,83]. Harbor seals (Phoca vitulina) are an excellent indicator species because they are long-lived and upper-level trophic consumers that inhabit coastal areas throughout the northern hemisphere.…”

“…Long-term monitoring of marine mammal health includes measuring contaminants, trace elements, biotoxins from harmful algal blooms, baseline blood values, and prevalence of infectious disease so that deviations from normal values may be detected [10,12,32,33,[35][36][37][38]. Cumulative effects of one or more of these factors may have contributed to the deterioration of marine mammal health [10,11,13,35]. Because infectious marine diseases appear to be increasing and are of immediate concern to marine mammal health, the dynamics and virulence potential of aquatic microbes should be investigated [4,10,28,38,48,75].…”