RODENT

 CHAPTER 3

RODENT 

Characterized by single pair of incisor teeth on each jaw and by absence of canine teeth.


Have tail with fine scales and few hairs.

Problems

• Spread serious diseases, including salmonellosis (food poisoning), leptospirosis, rickettsialpox and     lymphocytic choriomeningitis.

• Carry fleas, ticks and other ectoparasites, potentially spread diseases, such as bubonic plague.

• Consume or contaminate about 20 percent of the world’s food supply.

• Gnaw, expensive structural damage, start fires if they gnaw on electrical wires.

• Cause a great deal of anxiety for occupants (people and pets) of infested buildings.

• Pose serious risks for food facilities. Single rodent can cause fines, poor inspection scores, disgruntled employees and lost business.

Commensal Rodents

Species of rodents we deal most are:

• Roof rats (Rattus rattus),
•  Norway rats (Rattus norvegicus)
•  House mice (Mus musculus).

Members of Rodentia,family Muridae.

These rodents are"commensal"because they tend to live in close proximity to humans and eat the same food as we do.

They destroy property, frighten people & compete with human for food.

Rats plague many store owners and farmers.

Undesirable in feed and seed stores because destroy the seed, corn etc.

Undesirable in poultry houses and bird farms

Destroy & contaminate structure as well as harm young birds and chicks.

Bionomic factors of rats

• Sensory organ

•  Long mustache and other fine hairs on their body – Sensitive hair helps them

• Smelling organ

• Very sharp smelling organ
• When active, they shake their head and smell
• They leave special odour as movement guide  - Urine and genital fluid

• Hearing

• Detect sound up to 100kHz – House rats – 90kHz
• Afraid of high level noise

• Vision

• Useful for night vision
• High sensitivity of light but impaired vision 
• Can see as far as 15m distance

• Taste

• Very good tasting organ
• Ability to differentiate a plain bate and a poisonous bate

• Physical abilities

•  A good swimmer and diver
•  It can swim up to 1.4km/h
•  It can climb anywhere
• It can fall from 15 feet without suffering from any injury 
• Good balancing

Norway Rats (Rattus norvegicus)

• Sometimes called brown or sewer rats

• Burrows found along building foundations, beneath rubbish or woodpiles, and in moist areas in and   around gardens and fields.

• Nests may be lined with shredded paper, cloth, or other fibrous material.

• When Norway rats invade buildings, they usually remain in the basement or ground floor.

Appearance

• Up to 40 cm in length, tail shorter than the head and body.

• 350 – 500g in weight.

• Blunt nose, small ears and a thicker body when compared to the Roof Rat.

Lifecycle

• 7 – 8 young per litter; 3 – 6 litters a year.

• Gestation period of about 3 weeks.

• 10 – 12 weeks from birth to sexual maturity.

Habits

• Usually ground living and burrowing, but sometimes climbs.

• The only species to occur in sewers in Malaysia.

• Preferred food is cereals.

• Will eat around 30g of food a day and drink 60ml.

Roof Rats (Rattus rattus)

• Sometimes called black rats.

• Slightly smaller than Norway rats.

• Tails are longer than their heads and bodies combined.

• Very agile climbers and usually live and nest above ground in shrubs, trees, and dense vegetation        such as ivy.

• In buildings, most often found in enclosed or elevated spaces in attics, walls, false ceilings, and            cabinets.

• Preferring ocean-influenced, warmer climates.

Appearance

• 16 – 24 cm in length, with a tail longer than the head and body.

• 150 – 200g in weight.

• Pointed nose, large ears, slender body when compared to the Norway Rat .

Lifecycle

• 5 – 10 young per litter; 3 – 6 litters a year.

• Gestation period of about 3 weeks.

• 12 – 16 weeks from birth to sexual maturity.

Habits

• Rare in Malaysia. Appearance confined mainly to ports.

• Often climbs, agile, rarely burrowing and rarely outdoors in Malaysia.

• Preferred food is moist fruits.

• Will eat around 15g of food a day and drink 15ml.

House mice (Mus musculus) 

• Domestic house mouse

• Live and thrive under a variety of conditions in and around homes/farms.

• Contaminate food-preparation surfaces with their feces, which can contain the bacterium that causes       food poisoning (salmonellosis).

• Constant gnawing causes damage to structures and property.

Appearance

• 7 – 9.5cm in length, with a tail around the same length.

• 12 – 30g in weight.

• Small feet & head and large eyes & ears.

Lifecycle

• 4 – 16 young per litter; 7 – 8 litters a year.

• Gestation period of about 3 weeks.

• 8 – 12 weeks from birth to sexual maturity.

Habits

• Usually ground living and burrowing, but often climbs.

• Preferred food is cereals.

• Will eat around 3g of food a day and can survive without any additional water.

• They will drink up to 3ml a day if their diet is particularly

Signs of rat’s presence

• Faeces

• Footprints • Runway

• Smears

• Bitemarks • Burrows

• Smell

• Urine

• Live rat

• Carcass

• Nest

Public Health Issues

• Rats play an important role as host for certain infectious diseases

• Means of disease spreading might be directly or indirectly.

• Direct

• Rats carry germs inside their body (organisma eg: bacilli, spirochaetes, rickettsia, viruses, nematodes)

• Indirectly

•  Rats being a host for fleas, mites etc.

Rodents and Human Health

• Disease related to rodents:

• Hantavirus Pulmonary Syndrome 
• Haemorrhagic Fever
• leptospirosis
• Human Lymphocytic Choriomeningitis (LCM) Plague
• Rat-Bite Fever
• Salmonellosis 
• Murine Typhus

 Rodent Control Measures

1. Eliminating sources of food.

2. Eliminating breeding and nesting places.

3. Rat-proofing buildings and other structures.

4. Killing them.