MPD3223_VECTOR AND PEST CONTROL: RODENTS

ASSALAMUALAIKUM..Today I want to SHARE about rodent.

The characteristic of rodents is

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

v Have tail with fine scales and few hairs.

The problems related with rodents :

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

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

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

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

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

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

Types of rodent :

v Roof rats (Rattus rattus)

v Norway rats (Rattus norvegicus)

v House mice (Mus musculus)

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

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

v Rats plague many store owners and farmers.

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

v Undesirable in poultry houses and bird farms

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

Different characteristic of rats :

CHARACTERISTIC	NORWAY RAT	ROOF RAT	HOUSE RAT
Nickname	Sometimes called brown or sewer rats	Sometimes called black rats	Domestic house mouse
Weight	284 – 482g	170 – 340g	18 – 28g
Total Weight (Nose to tip of tail)	12 to 18 inches	13 to 17 inches	6 to 7 inches
Tail	Shorter than head plus body, 6 to 8 inches	Longer than head plus body, hairless 7 to 10 inches	Equal to or a little longer than body plus head, 3 to 4 inches
Ear	Small, close set, appear half buried in fur	Large, prominent, stand well out from fur	Prominent, large for size of animal
Fur	Coarse, generally red- brown to gray-brown colour.	Black to brownish, gray to white below.	Silky, grayish-brown on top, light cream underside.
Lifestyle	7 – 8 young per litter; 3 – 6 litters a year. Gestation period of about 3 weeks. 10 – 12 weeks from birth to sexual maturity.	5 – 10 young per litter; 3 – 6 litters a year. Gestation period of about 3 weeks. 12 – 16 weeks from birth to sexual maturity.	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 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.	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.	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 dry.

DIFFERENT TYPES OF RATS

Signs of rats presence :

v Faeces

v Footprints

v Runway

v Smears

v Bitemarks

v Burrows

v Smell

v Urine

v Live rat

v Carcass

v Nest

EXAMPLE OF SIGNS OF RATS

Public Health issues

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

v Means of disease spreading might be directly or indirectly.

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

v Indirectly – Rats being a host for fleas, mites etc.

Disease related to rodents:

v Hantavirus Pulmonary Syndrome

v Haemorrhagic Fever

v Leptospirosis

v Human Lymphocytic Choriomeningitis (LCM)

v Plague

v Rat-Bite Fever

v Salmonellosis

v Murine Typhus

What is Leptospirosis:

Leptospirosis is an infection in rodents and other wild and domesticated species. Rodents are implicated most often in human cases. The infection in man is contracted through skin abrasions and the mucosa of the nose, mouth and eyes. Exposure through water contaminated by urine from infected animals is the most common route of infection. Human-to-human transmission is rare.

Outdoor and agricultural workers (rice-paddy and sugarcane workers for example) are particularly at risk but it is also a recreational hazard to those who swim or wade in contaminated waters. In endemic areas the number of leptospirosis cases may peak during the rainy season and even may reach epidemic proportions in case of flooding because the floods cause rodents to move into the city.

Prevention strategies of human leptospirosis include wearing protective clothing for people at occupational risk and avoidance of swimming in water that may be contaminated. Leptospirosis control in animals is dependent on the serovar and animal species but may be either vaccination, a testing a culling programme, rodent control or a combination of these strategies.

TRANSMISSION

What is Plague

Cause : The plague bacillus, Yersinia pestis.

Transmission :

Plague is a zoonotic disease affecting rodents and transmitted by fleas from rodents to other animals and to humans. Direct person-to-person transmission does not occur except in the case of pneumonic plague, when respiratory droplets may transfer the infection from the patient to others in close contact.

Nature of the disease:

Plague occurs in three main clinical forms:

Bubonic plague is the form that usually results from the bite of infected fleas. Lymphadenitis develops in the drainage lymph nodes, with the regional lymph nodes most commonly affected. Swelling, pain and suppuration of the lymph nodes produces the characteristic plague buboes.

Septicaemic plague may develop from bubonic plague or occur in the absence of lymphadenitis. Dissemination of the infection in the bloodstream results in meningitis, endotoxic shock and disseminated intravascular coagulation.

Pneumonic plague may result from secondary infection of the lungs following dissemination of plague bacilli from other body sites. It produces severe pneumonia. Direct infection of others may result from transfer of infection by respiratory droplets, causing primary pulmonary plague in the recipients.

Geographical distribution :

There are natural foci of plague infection in rodents in many parts of the world. Wild rodent plague is present in central, eastern and southern Africa, South America, the western part of North America and in large areas of Asia. In some areas, contact between wild and domestic rats is common, resulting in sporadic cases of human plague and occasional outbreaks.

Risk for travellers :

Generally low except in rural areas of countries or areas at risk, particularly if camping or hunting or if there is contact with rodents.

Prophylaxis :

A vaccine effective against bubonic plague is available exclusively for individuals with a high occupational exposure to plague; it is not commercially available in most countries.

Precautions: Avoid any contact with live or dead rodents.