Rodent Borne Diseases

Duncan Bosomworth, NPTA Technical Manager

The funny thing about this subject is that we all know about rodents and the reasons why they’re identified as public health pests, but we never really go into the detail about exactly what the risks are.

No doubt we can all list the diseases they carry (some more than others) and if you’re like me, you’ll say Weils Disease as your first answer and then one of the food poisoning diseases like Salmonella and be happy there.

God knows how many times I’ve been ill through the diseases associated with food poisoning since my first days as a pest control tech in London, I’d say that it was a split between eating out at dodgy restaurants, some self-imposed poisonings (mixing cooked and uncooked meats) and a couple of industry induced events, one being a customer “gifting” me Campylobacter at his poultry site.

 

Hanta-Virus

Top of the list of diseases at the moment is of course Hanta-virus. This disease is commonly associated with the physical disturbance of dried-up rodent droppings normally through cleaning of contaminated areas, basically the dust particles containing the virus become air-borne and you breath them in. Interestingly it can also be spread via urine and saliva from infected animals so be aware.

Two main types of Hanta-virus are Haemorrhagic Fever with Renal Syndrome (HFRS)- found in the Americas and Hantavirus Pulmonary Syndrome (HPS)- found in Europe and Asia. One variant of the HFRS strain (Andes Virus) can be spread from human to human and can result in death in 50% of cases, this was the variant found on the cruise ship in the news recently. Wearing the correct PPE, using the correct disinfectants and safeguarding others when you are cleaning places previously infested with rodents is really important. Consider this when you are creating RAMS for cleaning jobs in lofts, under floors and other areas where rodents have left their calling cards.

 

Leptospirosis

Leptospirosis is one of the most commonly known rodent borne diseases though is rarely fatal as anti-biotics soon bring it under control before it kills you. The damage to your organs as a result of getting Weils Disease (which leptospirosis can lead to) can be profound and effect you for the remainder of your life. It is a rare disease in the UK with very few people actually get diagnosed with it let alone dying from it. Like all of these diseases you can’t visually tell if the environment you are in is infected with the disease so it’s best to assume the worst in my view and think that all rats carry it, the bacteria can live for months in soil let alone water sources. Wear gloves, cover any cuts and wash your hands before you go to the loo as well as afterwards!

 

Food Poisoning Diseases

The classic food poisoning diseases like E-Coli, Campylobacter and Salmonella are carried by rodents and are commonly associated with poultry, raw meat and offal. Cross contamination is a common cause of the spread of the bacteria onto foods not normally linked to these diseases either through poor hygiene practices  or actual contamination caused by wandering rodents, mice are a common culprit due to their habit of repeatedly urinating and defecating as they wander around their surroundings. Again watch where you put your hands even when you’re just dealing with mice.

 

Cryptosporidiosis

Cryptosporidiosis is a disease caused by the parasite Cryptosporidium, you can get infected with the parasite through contaminated soil, water courses and rodent faeces so wear gloves and sometimes a mask when carrying out rodent control to limit exposure to things that can affect your health. The most hazardous things in my mind are these potentially lethal pathogens. This disease is a hundred times more likely to get you than leptospirosis and I bet you have never thought about it! Rarely fatal in the UK it does however take out nearly 200,000 people a year worldwide.

 

Giardiasis

Giardiasis is very similar to Cryptosporidiosis, another parasitic disease that effects mainly the young and vulnerable in our society, it can affect anyone really, just the young and old are affected the most. Children’s nurseries and care homes have to be very vigilant, symptoms are shared with many other less harmful diseases, rodent infestations and contaminated water supplies are the most likely route into such establishments. When you consider that over 50% of rats and mice carry the parasite it makes you think why so many care homes have pest control nowadays.

 

Toxoplasmosis

Toxoplasmosis is normally linked to cats and their faeces, the parasite that causes it  can infect you and you may not even realise as it can be totally asymptomatic, sometimes you may feel a bit low, mild flu like symptoms again being a common sign of something being present in your system, however what it can do to immunocompromised people and pregnant women is another matter altogether,  if they get too close to cat faeces they may be exposed to the parasite (so be careful gardening and handling litter trays, better still don’t). You can get infected when handling raw meat too so be warned. Why is it so dangerous to expectant mothers? Well it can and most likely will cause some severe medical conditions to their unborn baby. Cats get infected from the rodents they catch when they’re out all night hunting, so when you’re out killing rodents and people ask you why you do such a thing tell them the link.

 

Lyme Disease

Lastly there’s the issue of killing field mice and how they aren’t always classed as a pest and should be left alone for the owls and the kestrels to eat. By the way I’m in full agreement with CRRU in that we need to be careful using AVKs when there are field mice around; as you will probably know  there is one bait on the market cleared for controlling field mice as the risks of secondary poisoning aren’t present using it. So why am I banging this drum? In food sites they can cause issues; every winter they move into our homes and need to be controlled but have you ever heard of Lyme disease?

So, 70-90% of field mice carry ticks, up to 15% of these ticks carry Lyme disease, if you are unfortunate enough to get bitten by a tick there is a 1 in 10 chance of the disease entering your body. Around 2000 people get Lyme disease each year. The resultant health conditions associated with the disease can remain with you for the rest of your life, similar to Leptospirosis. If you get bitten by a tick, seek medical advice immediately, getting anti-biotics into your system within 24 hours is highly recommended especially if the tick was attached to you for a long period of time.

Sleep well!