Rats Fleeing a Sinking Ship (AKA: Hold your breath)

It just hit the news –

Hantavirus is typically spread through the feces and urine of rodents. There has been mention of human-to-human transmission, but according to a 2022 paper reviewing that claim, “The balance of the evidence does not support the claim of human-to-human transmission.”

It’s important to remember that Hantavirus is not a “flu-like symptoms” sickness. It can be, and in this case is, a lethal disease. Sure, it starts with flu-like symptoms but progresses quickly to coughs and shortness of breath. It has a mortality rate of about 33%. For reference, the common cold has a less than 1% mortality rate and tuberculosis has a rate of about 15%. Of course, those who are very young, very old, or who have compromised immune systems are most at risk.

So what happened here?

It’s a bit soon to tell and the WHO is actively investigating. The news has been careful to report that human-to-human transmission is possible, but the literature doesn’t support that claim very well. That doesn’t mean it can’t be. Viruses are constantly adapting and changing so there could be a new strain that is more communicable by humans. I’m going to be bold and say it wasn’t and that there were rodents involved.

What makes me think this? It is the most common form of transmission. Hantavirus infects people who breathe in the aerosolized particles of urine and feces. It can also be transmitted through contaminated food. The virus can stay active for 10 days at room temperature. Rodents are small, sneaky, and reproduce quickly. They also urinate and defecate EVERYWHERE they travel. It is much more likely (though I will admit not 100%) that rodents were involved than just person-to-person transmission.

Is it possible that rodents were on the ship? Absolutely. Pest control on any type of maritime vessel is necessary because ships stop in ports (infested with rodents), load up provisions (potentially infested), and there is plenty of food and hiding spots onboard for them to flourish. It’s not just rodents, it’s flies (which are notorious for spreading diseases), cockroaches (same), and other insects.

A cruise ship is a floating island of people and food. It’s a bit like a city where people are packed into a small area. Think back to the black plague in Europe. Rodents and fleas were implicated in the spread and people lived very close together in rather unhygienic conditions. I am not saying the cruise ship was necessarily unhygienic. But when you stick lots of people in a very small space, all eating the same foods, and cleaning practices get lax, you increase the chances.

A few years ago, it was big news that norovirus was running rampant through a few cruise ships. Norovirus is spread through people ingesting substances contaminated with feces. If fecal-oral transmission was commonly happening, feces-inhalation is certainly likely with rodents on board the ship. In a closed system like a cruise ship, multiple people can easily pick up the virus if they are in the area where the rodents were defecating and urinating. Even if the rodents were isolated to a few areas, say just the gym of the ship, everyone who visits that gym area can breathe in those particles.

From a pest control standpoint, the ship needs an intense inspection. Food sources and any conducive conditions have to be identified and corrective actions put in place. Monitoring devices need to be used to identify the areas they are in so that control measures can be put in place. Rat guards must be in place and properly placed when the ship is docked. On my last cruise, I noticed many of these sort of haphazardly placed and a rodent could easily go around them or jump from the line to the ship.

Obviously, the ship needs to institute some massive cleaning protocols. Cleaning protocols, timings, and training need to be evaluated and improved moving forward. Pest control is always a partnership between the customer (cruise ship) and the pest control provider. Each has their role to play in the system.

To reduce exposure, people can wear masks, but who wants to wear a mask 24/7 while on holiday?

This is a good reminder that nowhere is safe from pests. If there is food, water, and shelter, they can take advantage of that. Pest control is necessary to protect human health. This time it’s Hantavirus. Next time, it could be something worse.

For the cruise lines out there, I’m happy to come do an independent inspection…. Especially if the ship is going somewhere fun! For everyone else, I can help you improve your programs to protect your clients. Contact me!

Lagniappe - do rats flee a sinking ship?