The Body Shop used to sell bags saying something like “if you think you’re too small to be noticed, go to bed when there’s a mosquito in the room”. Apparently they were right.
William Nami was a railway worker whose job was to work in a team operating a ‘tamper’ (a machine for repairing railway lines). Sometimes he worked inside the machine’s poorly-sealed cabin, and sometimes outside. Unfortunately, the area in which he worked was mosquito-infested town of Sweeny in Brazoria County, Texas. The railway’s right of way was narrow and weed-strewn and sometimes had pools of water. In late September 2008 Nami was diagnosed with West Nile virus and suffered significant ill effects. He sued his employer under §51 of the the Federal Employees Liability Act:
Every common carrier by railroad … shall be liable in damages to any person suffering injury while he is employed by such carrier … for such injury … resulting in whole or in part from the negligence of any of the officers, agents, or employees of such carrier.
He alleged that the employer had failed to provide a safe workplace. A jury at trial found tat the employer had been negligent and awarded damages: Nami v Union Pacific Railroad Co. (267th District Court, Koetter J, 2012, unreported). The employer’s appeal to the Court of Appeals was rejected: Union Pacific Railroad Co v Nami 499 SW 3d 452 (Tex. Ct App., 2014).
Union Pacific appealed to the Supreme Court of Texas. The Supreme Court noted that insects are considered to be wild animals (ferae naturae) and
… under the doctrine of ferae naturae, a property owner owes an invitee no duty of care to protect him from wild animals indigenous to the area unless he reduces the animals to his possession, attracts the animals to the property, or knows of an unreasonable risk and neither mitigates the risk nor warns the invitee. … The same rule applies to an employer’s duty to provide a safe workplace.
In this case the employer had done nothing to increase (and could have done nothing to decrease) the risk of mosquitoes to Mr Nami. Accordingly negligence was not made out.
Postscript – The Supreme Court of the United States declined to hear Nami’s appeal: Nami v Union Pacific Railroad Co., 137 S.Ct. 2118 (2017).