# Analysis of the Relationship Between Chemical Elements and Neural Necrosis Virus in Mugilids from the Southern Caspian Sea

## TL;DR

This study found that fish infected with a virus in the Caspian Sea had higher levels of certain metals, suggesting pollution may make them more vulnerable to disease.

## Contribution

The study links elevated metal concentrations in fish to increased susceptibility to Viral Nervous Necrosis in the Caspian Sea.

## Key findings

- Viral Nervous Necrosis was more prevalent in Chelon saliens compared to Chelon auratus.
- Infected fish showed significantly higher concentrations of Hg, Pb, Mo, V, and Cu.
- Mercury levels were up to tenfold higher in infected fish, indicating a strong pollution-health link.

## Abstract

For years, the Caspian Sea has been affected by chemical pollution resulting from human activities. More recently, Viral Nervous Necrosis (VNN) has emerged as a new threat, severely impacting fish populations in this aquatic ecosystem. The aim of this study was to evaluate differences between healthy and VNN-infected mullets along the southwestern coast of the Caspian Sea. A total of 63 individuals were randomly sampled, including 34 Chelon auratus and 29 Chelon saliens. Viral prevalence was higher in C. saliens. Statistical test revealed clear differences between healthy and infected individuals based on their elemental profiles. Infection with NNV was associated with significantly elevated concentrations of several metals, particularly Hg, Pb, Mo, V, and Cu, with Hg showing up to a tenfold increase in infected fish. These findings confirm that the southern Caspian Sea is contaminated with multiple trace elements, which not only compromise ecosystem health but may also predispose fish to viral infections such as VNN.