RodentBiology & Control

Prevent Disease, Disability and Premature Death

Examples of RodentsGerbils

Mice

Rats

Squirrels

Woodchucks

Porcupines

Beaver

and….

Prevent Disease, Disability and Premature Death

Relate the biology of rodents to appropriate control measures.

Objectiveهدف

Prevent Disease, Disability and Premature Death

Chacteristics and Habits

Purpose

Surveillance and Control Techniques

Overviewمرور

Prevent Disease, Disability and Premature Death

Norway RatRattus norvegicus

Characteristics:Large, thick body

Largest, most aggressive

Blunt muzzle; small ears and eyes

Tail is nearly naked; shorter than combined length of head and body

Fur color brown to dark gray with scattered black hairs

Prevent Disease, Disability and Premature Death

Roof RatRattus rattus

Characteristics:Relatively slender body

Muzzle pointed; ears and eyes large

Tail longer than combined length of head and body; fairly hairy

Fur color black to brownish-gray

Prevent Disease, Disability and Premature Death

House MouseMus musculus

Characteristics:Body small

Ears and eyes large

Fur color grayish-brown with light below

Can be distinguished from immature rats by head and feet proportion in relation to body (young rats have large heads and feet)

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ReproductionRats

Sexually mature at 3 months

Gestation period 21 days; new estrus cycle begins 4-5 days following litter birth

Produce 3-7 litters per year with 5-7 pups per litter

Mice

Sexually mature at 5 weeks

Produce up to 8 litters per year at 5-6 pups each

Prevent Disease, Disability and Premature Death

Rodent Behaviors

They are nocturnal -- active almost exclusively at night.

They stay close to food and water.

If abundant water is not available (or in poor supply), they will not continuously inhabit an area.

Prevent Disease, Disability and Premature Death

Rodent Behaviors

They travel in defined runways.

They are “neophobic” -- don’t like new objects.

They tend to eat in their harborages.

Prevent Disease, Disability and Premature Death

Rodent Behaviors

Climbing – Rodents are among the most agile of all mammals and are capable climbers

Burrowing – this activity is demonstrated by all commensal rodents with the Norway rat being most adept.

Prevent Disease, Disability and Premature Death

Rodent Senses & Abilities

Sensory acuity - hearing, taste and smell, are much more acute than humans.

Rodents have excellent memories and seldom repeat mistakes.

Prevent Disease, Disability and Premature Death

Senses and Abilities

Swimming – all commensal rodents are good swimmers with the Norway rat being the most adept at this activity.

Prevent Disease, Disability and Premature Death

Medical Importance

Native rodents may contribute to disease (ex. plague and Hantavirus) or economic loss (ex. crop damage).

Imported species are far more destructive.

We are most concerned with commensal rodents: those rodents that are closely associated with man and his environment (derived from the Latin word for "companion at meals.”)

Prevent Disease, Disability and Premature Death

Medical Importance

Rodents can attack people, especially when their populations are large or they are hungry

Rodents historically have been a problem on battlefields and will attack wounded and disabled soldiers

Prevent Disease, Disability and Premature Death

Diseases Associated with Rodents

Plague

Tularemia

Leptospirosis

Salmonellosis

Relapsing fever

Leishmaniasis

Korean hemorrhagic fever

Ratbite fever

Hantavirus

Mosquito- and tick-borne encephalitides

Chikungunya, Onyongyong fever, Lassa fever

Crimean-Congo hemorrhagic fever

Murine and scrub typhus

Tickborne typhus, Q fever

Toxoplasmosis

Helminthic disease (trichinosis)

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Rodent Attacks

Rats can injure, maim, and kill people!

Prevent Disease, Disability and Premature Death

Economic Significance

Destroy stored grains, and other foods

They will eat almost anything

Destroy other structures by gnawingIncludes electrical wires, hydraulic hoses, wood, and wallboard

Gnawing - rodents gnaw constantly to wear down teeth

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Surveillance

Presence of urine and feces...Rat urine glows under black light

Smudge marks or rubs

Runs or tracks

Prevent Disease, Disability and Premature Death

SurveillanceGnawing or other physical damage

Burrows, nests, or food caches

Presence of dead rodents in the open.

Presence of live rodents in the day.

Prevent Disease, Disability and Premature Death

Surveillance

Odors and sounds

Visual observation

Pet excitement

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Prevention and Control

SanitationIPM

Exclusion and rodent proofing

Prevent Disease, Disability and Premature Death

Rodenticides

Acute (Single-Dose) Rodenticides : Capable of killing in a single dose, although more effective over multiple feedings

Chronic (Multiple-Dose) Rodenticides: Requires multiple feeding over several days to cause mortality

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Other Control Methods

Trapping

Snap traps

Live traps

Sticky traps

Prevent Disease, Disability and Premature Death

Summary

Chacteristics and Habits

Purpose

Surveillance and Control Techniques

Prevent Disease, Disability and Premature Death

Questions?

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