Pest Advice Blog

Rats and Mice as Vectors of Diseases

mouse The word “rodent” is derived from the Latin verb rodere, meaning “to gnaw”, and rats in particular are infamous for their ability to chew through insulation and wiring in your home. With sensitive whiskers and guard hairs, rats are perceptive to touch, which is why you’ll often spot them running along walls and in between objects. Even though rats are known to have poor eyesight, their sense of smell and taste are quite sharp and these traits serve them well in foraging for food in the cover of night. Probably the least aesthetically pleasing of the rodent family, rats have a notorious reputation for their ability to destroy properties, by gnawing at structure bases and wiring, which can cause fires.

In comparison, mice are the smaller of the two but are also capable of gnawing at structures, especially those made of wood. Both rodents and mice compete with us for food sources and can wreak havoc on agriculture and stores of food.

Perhaps the worst offence is their ability to ‘vector’ diseases, fueled by their habits of using our waste and sewage coupled with their characteristically mobile nature. According to The Center for Disease Control, both rats and mice are responsible for the transmission of over 35 diseases worldwide. Whether you live in a crowded, urban area or a more rural space, rats and mice do not discriminate based on environment and can be successful in any habitat. Their close proximity to where we eat, live and go about our daily lives, can be disconcerting as there are many dangerous rodent- associated diseases that can affect humans such as: Hantavirus, rat-bite fever, plague, murine typhus, leptospirosis, lyme disease, swine dysentery and salmonella. Through their fur, saliva, urine and droppings, rats and mice can transfer diseases from contaminated areas and accelerate the spread of these diseases at a rapid rate.

What is a Vector?

According to the World Health Organization (W.H.O.), vectors are living organisms that can transmit infectious diseases between humans or from animals to humans. More commonly known vectors are fleas, mosquitoes and rats with the W.H.O. citing over 1 billion cases and over 1 million deaths from vector-borne diseases each year. In fact, vector-borne diseases account for over 17% of all infectious diseases today.

Diseases spread by rodents

Referred to as the “Black Death” the bubonic plague is one of the most widely known rodent vectored diseases, responsible for the majority of deaths during the Medieval era in Europe. Today, plague still kills many people all over the world, but other diseases have developed that can have far greater impact especially in countries that lack resource to combat this problem.

Some diseases that are directly or indirectly spread by rodents are:

  • Lassa Fever
  • Hantavirus Pulmonary Syndrome
  • Leptospirosis
  • Plague
  • Rat-bite fever
  • Salmonellosis
  • South American Arenavirus
  • Tularemia
  • Colorado Tick fever
  • Rickettsialpox
  • Babesiosis

Types of Rats & Mice: Ratatouille anyone?

The most common types of rats that come into close contact with humans are the Norway rats and Roof rats.

norway_rat Norway rats or brown rats are larger than roof rats and tend to burrow themselves under trash or lower levels of buildings. They are sometimes called sewer rats with short tails and small ears and eyes and will often build their nests out of cloth, shredded paper or fibrous material. They are extremely common in densely populated areas.

Roof rats or black rats are often found in coastal areas. Due to their superior climbing skills, they make their nests above ground in shrubs and trees. This also means that they are able to enter your home through trees that are close to windows, and can often be found in elevated areas such as walls, cabinets and attics.

Rats are excellent swimmers and can leap as high as 3 or 4 feet. Feasting on a variety of both plant and animal foods, rats need constant access to water. Signs of rats in your home can be easily identified by small holes in door frames or wooden baseboards, small burrows outside your home, as well as the presence of ½ inch droppings throughout the house.

Move over Mickey!

mice When we think of mice, we’re often not as grossed out by their presence as we are with their more fearsome counterpart the rat. However, mice are just as responsible for an unhealthy living environment and should not be undermined as a serious issue.

For homeowners, there are a few more common species of mice that can cause problems including the native mouse (such as the deer and white-footed), as well as the house mouse. As with rats, mice eat both plant and animal foods, but also prefer seeds and grains. They are not as dependent on a constant water source as with rats, often relying on the moisture from food to sustain them.

House mice can often be found in small spaces behind walls or appliances. In the winter months, the native mice will be sure to seek shelter indoors to escape the cold.

Even if you are not aware of the presence of mice and rats in your home, there are many unseen ways that these rodents can transmit their diseases:

  • In the case of Hantaviruses, people can become infected if the rodent dropping or urine contains a Hantavirus which may infiltrate dust that can be breathed in by humans.
  • Eating or drinking food or water that is contaminated with rat feces.
  • Direct contact with live or dead rats that are infected.
  • In rare cases, rats directly biting a human.
  • Bites from fleas or mites that are found on rats.

How to prevent a rodent infestation

The best method for preventing a rodent infestation is to eliminate the food sources that attract rodents and keep them out of the home by using an exclusion method of pest control. As a preventative measure, there are steps you can to help prevent an infestation:

  • Store food in airtight containers and avoid keeping food out on countertops overnight.
  • Pet food should not be kept outside, and if stored in pantries or basements, should also be sealed in airtight containers.
  • Keep indoor trash in lidded bins wherever possible.
  • Since mice in particular are drawn to nesting areas, avoid keeping piles of boxes, papers or clothes. This is applicable to the outside of your home where rats are more likely to make their way to piles of items and trash that may be left unattended.
  • Any entryway into the home should be checked to make sure that there are no openings for rats and mice to get through. If there are holes in floors, doors or walls, a combination of wire mesh and foam sealants can be used.

If you do have a rodent problem that seems overwhelming, it is important to contact your local Truly Nolen service experts to identify areas where these rodents are possibly entering your home. The Exclusion Method of rodent control is one of the most effective ways for your service expert to ensure that mice and rats cannot enter your home in any way. The application of this method can aid in solving the problem at its source, so that any remaining rodents on the interior of the home can be eliminated.

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