Understanding Marine Turtle Tumors and Viruses: A Comprehensive Health Review

Jenn Hoskins
27th June, 2024

Understanding Marine Turtle Tumors and Viruses: A Comprehensive Health Review

In North-Western Mexico, fibropapillomatosis predominantly affects olive ridley sea turtles, Lepidochelys olivacea (left), and green sea turtles, Chelonia mydas (right), which together constitute over 96% of the disease cases reported in the region.

Composite: Natural Science News / CC BY. [Sources]
Adapted from photos by:

Key Findings

  • The study focused on the prevalence of fibropapillomatosis (FP) and its associated virus, chelonid alphaherpesvirus 5 (ChHV5), in marine turtles in North-western Mexico
  • Researchers identified 32 cases of FP and/or ChHV5 infections from 18 reports, with Baja California Sur having the highest number of cases
  • The study suggests a significant increase in FP cases over the past decade, with tumors primarily found on the anterior flippers and neck of affected turtles
Fibropapillomatosis (FP) is a disease affecting marine turtles globally, characterized by the formation of cutaneous tumors that can appear anywhere on the body. A recent study conducted by researchers from Universidad Autónoma de Baja California Sur[1] explored the prevalence and emergence of FP and its associated virus, chelonid alphaherpesvirus 5 (ChHV5; Scutavirus chelonidalpha5), in North-western Mexico. This region is crucial for the feeding, development, and reproduction of five of the seven existing sea turtle species. The researchers conducted a comprehensive literature search spanning from 1990 to 2024, focusing on the feeding sites in this region. They identified 18 reports documenting 32 cases of FP and/or ChHV5 infections in coastal and insular areas. Notably, Baja California Sur had the highest number of cases, accounting for 75% of the total. The first case of ChHV5 infection was reported in 2004, while FP tumors were first noted in 2014, becoming more frequent between 2019 and 2024. The affected species included black turtles (Chelonia mydas, 50%), olive ridley turtles (Lepidochelys olivacea, 46.8%), and loggerhead turtles (Caretta caretta, 3.2%). Tumors were primarily found on the anterior flippers (46.1%) and neck (22.5%), often presenting a nodular and verrucous appearance with a rough surface. This study suggests a potential emergence of ChHV5 infections and FP disease in the last two decades, with a significant increase in the past ten years. The findings align with previous research indicating that ChHV5 is present in both symptomatic and asymptomatic turtles worldwide[2]. Higher concentrations of ChHV5 DNA have been found in FP tumors compared to non-tumor tissues, supporting the theory that the virus is ubiquitous and may require environmental or immune-related co-factors to induce FP[2]. The emergence of FP in marine turtles could be influenced by various factors, including anthropogenic activities. Pollution has been linked to increased cancer rates in wildlife, and FP is a transmissible neoplastic disease[3]. The interconnectedness of aquatic ecosystems means that pollutants can easily spread, potentially impacting turtle health. Understanding the physiological mechanisms connecting pollution to oncogenic processes in non-model organisms like marine turtles is crucial. This can help predict the vulnerability of different wild populations to oncogenic contamination and inform conservation strategies[3]. Additionally, the role of environmental stressors, such as climate change and chemical pollutants, cannot be overlooked. Marine mammals have been proposed as sentinel species to evaluate aquatic ecosystem health, as they share the coastal environment with humans and consume the same food[4]. Similarly, marine turtles could serve as indicators of environmental health, reflecting the impacts of pollution and emerging diseases. The study by Universidad Autónoma de Baja California Sur highlights the importance of a One Health approach to understand and improve sea turtles' health. This approach considers the interconnectedness of human, animal, and environmental health, emphasizing the need for comprehensive strategies to address the factors contributing to the emergence and spread of diseases like FP. By integrating findings from various studies and focusing on the broader ecological context, researchers can develop more effective conservation measures to protect marine turtles and maintain the health of aquatic ecosystems.

HealthAnimal ScienceMarine Biology

References

Main Study

1) Epidemiology of marine turtle fibropapillomatosis and tumour-associated chelonid alphaherpesvirus 5 (ChHV5; Scutavirus chelonidalpha5) in North-Western Mexico: a scoping review implementing the one health approach

Published 26th June, 2024

https://doi.org/10.1007/s11259-024-10429-6

Related Studies

2) Further evidence of Chelonid herpesvirus 5 (ChHV5) latency: high levels of ChHV5 DNA detected in clinically healthy marine turtles.

https://doi.org/10.7717/peerj.2274

3) Linking pollution and cancer in aquatic environments: A review.

https://doi.org/10.1016/j.envint.2021.106391

4) Marine mammals as sentinel species for oceans and human health.

https://doi.org/10.1177/0300985810388525


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