RODENT CONTROL AND PREVENTION OF DISEASES

               Rodents are the source and reservoir of more than 15 percent of animal borne diseases known up to till now.Rodents act as hosts to several parasites causing human and animal diseases.The flea is the most important parasite from the medical point of view.Rats are great destroyers of food grains and standing crops.They destroy more than 10 times they consume.They are nuisance to eggs and poultry which they eat and destroy more than other wild mammals.They cause damage to buildings,dams and structures.They destroy articles of clothing,furniture,leather,electric wires,etc.

They serve as international conveyers of epidemic diseases like plague,and it is noticed that the great plague epidemics in the past were due to migration of infected rats on ships from China to India,Middle east,Europe and South America.

2.Rodent control is obtained by denying them nesting,breeding and hiding places and also denying them food and destroying them.To achieve these measures are anti rodent hygiene,anti rodent engineering,anti rodent house keeping and active and combined destruction measures.Trapping and poisoning are the two main proceedures are normally used for the destruction of rats.Rats enter houses through drain pipes left open,through doors and windows and out side,fittings,through the lower parts of the doors,ventilators,unused chimney flues and so on.The doors and windows must be tight fitting and reinforced with metal sheets to keep the rats from destroying through the basement and upper windows.All water and drain pipes should be surrounded by concrete where they pierce the walls.The main sanctuaries for rats are the provisional stores,markets,slaughter houses,diary farms,restaurents,bakery,shops and human dwellings,etc in cities,and corn godowns,cattle sheds,piggeries etc are in rural areas.which afford them nesting,breeding and feeding for rats.In rural areas the field rats can not be controlled by rat proofing of houses and godowns,for there is a continual sufficiency of food.Rat burrows can be closed with mixture of cement,sand and broken glass.Provision stores should be protected by wire screens.In rural and urban areas the access of rats to places where they can secure nesting facilities and food should be barred.Garbage and offal must be disposed of by burning.A very high standard of sanitation and general cleanliness in and around houses,godowns,factories,provision stores,market places and slaughter houses avoids the rat of places for nesting,breeding and resting.Trapping can reduce the population of rats soon,if the the traps are properly set and baited.For destruction of rats poisoning campaign should be carried out.The main natural enemies of rats are the cats,eagles,vultures,owls,foxes,mangoose and dogs etc.Some of these may help to reduce the rat population to some extent,none of them is practicable value in the rat control programmes.Diseases mainly conveyed to human beings are Rat fever/Weil's disease,(Leptrospirosis),Rat bite fever,Plague,Murine Typhus,etc.

3.Leptospirosis/Weils disease(Rat fever).This is commonly known as Weils disease.This a sudden infection characterised in human beings by fever,albumen present in urine,bleedings,head ache and pains in the body,skin rashes,enlargement of liver and excretion of bile in urine and loose motions and abdominal pains.The natural reservoir and source are rats and field mice.These rodents are tolerant to this disease and do not suffer.The organism is excreted in their urine and faeces.The immediate source of infection to man is through contact with soil contaminated with infective excreta,specially urine.The entry in man is through microscopic cuts and abrasions sustained during works in soil,drains,sewers or bathing in contaminated water  also may give rise to out breakes.The out breaks may occur among farmers,miners and fishermen,etc.The incubation period is a week rarely up to 13 days.The patient's urine may be infective from the end of first week onwards from ten to 25 th day,but may extend upto 60 days in some rare cases.Rats are infective throughout their life.Man possess no natural immunity.the disease can be severe or mild course depending on the type of infecting organism.This disease is prevalent Japan and most countries in Europe and Asia.

4.Prevention and control:Rodent control in costal areas and sewers in urban areas.Swimming in infected pools should be avoided.Attendants should wear protective clothing.Disinfection of articles used by patient daily and also terminal should be ensured.Protective clothing for workers,speacially in trenches,sewers,divers.
pm kutty.