Rats around the house and in offices can be a serious nuisance. They not only cause damage by gnawing on cables, wires and plastic pipes – but they are a serious health risk as well.
Rats live on food and rubbish left in open areas, and use buildings – especially roofs – as shelter. Rats can cause fires and electrical shorts by gnawing on cables, water leaks by biting through pipes, and human diseases through their urine and feces.
Often seen in places where there has recently been demolition or construction work, where rubbish is lying around, in drains, as well as in rural areas, rats are a growing nuisance. With the abundance of food available, rats are less likely to take poisoned bait.
The average lifespan of a rat is 18 months and one pair can produce a colony of 2,000 rats in a year. In order to reproduce at such an alarming rate, up to 30% of the female rat population is pregnant at any time. Females become sexually mature at just 8-12 weeks, gestation is between 21 and 23 days, and females are able to conceive whilst suckling a previous litter, often mating within 18 hours of giving birth. They can breed throughout the year if the weather is mild and there is plenty of food. Up to 13 litters are possible each year, each one consisting of 7-9 young.
Rats eat the equivalent of 10% of their body weight daily, consuming rubbish, leftover dog food, bird food and even dog excrement. Rats are largely nocturnal but will feed in the day time if there is enough food laying around in streets or alley ways. So if you see a rat during the day time it’s probably because it’s been feeding on dumped household waste.
Diseases Transmitted by Rodents
Hantavirus Pulmonary Syndrome (HPS): Hantavirus pulmonary syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contract the disease when they breathe in aerosolized virus. HPS was first recognized in 1993 and has since been identified throughout the United States. Although rare, HPS is potentially deadly. Rodent control in and around the home remains the primary strategy for preventing hantavirus infection.
ain occurring in association with an increase in the number of eosinophils, white blood cells that are associated with infection with worms that penetrate into the body. The organism most commonly causing eosinophilic meningitis is a rat lung worm called angiostrongylus cantonensis.
Murine Typhus: Murine typhus (caused by infection with R. typhi) occurs worldwide and is transmitted to humans by rat fleas. Flea-infested rats can be found throughout the year in humid tropical environments, but in temperate regions are most common during the warm summer months. Travelers who visit in rat-infested buildings and homes, especially in harbor or riverine environments, can be at risk for exposure to the agent of murine typhus.
Rat-bite fever (RBF): Rat-bite fever (RBF) is a systemic bacterial illness caused by Streptobacillus moniliformis that can be acquired through the bite or scratch of a rodent or the ingestion of food or water contaminated with rat feces.
Salmonella enterica serovar Typhimurium: As its name suggests, it causes a typhoid-like disease in mice. In humans S. Typhimurium does not cause as severe disease as S. Typhi, and is not normally fatal. The disease is characterized by diarrhea, abdominal cramps, vomiting and nausea, and generally lasts up to 7 days. Unfortunately, in immunocompromized people, that is the elderly, young, or people with depressed immune systems, Salmonella infections are often fatal if they are not treated with antibiotics.
Leptospirosis: Leptospirosis is a bacterial disease that affects humans and animals. It is caused by bacteria of the genus Leptospira. In humans it causes a wide range of symptoms, and some infected persons may have no symptoms at all. Symptoms of leptospirosis include high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash. If the disease is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress. In rare cases death occurs.
Eosinophilic Meningitis: Eosinophilic meningitis is an infection of the brain occurring in association with an increase in the number of eosinophils, white blood cells that are associated with infection with worms that penetrate into the body. The organism most commonly causing eosinophilic meningitis is a rat lung worm called angiostrongylus cantonensis.