Rodents (as listed in the EFET-SEAME guideline)
Ordering
Rodents (Rodentia) are a class of placenta, creeping mammals, which includes many species. Of these, the species that are of health interest are the so-called symbiotic rodents, to which mice belong. Mice belong to the family Muridae, where the genus Mus belongs. The main species of mice are the rat Rattus norvegicus (Norwegian rat or large rat) and the Rattus rattus (brown rat or small rat) and the house mouse Mus musculus. All three species are very common in Greece.
Biology
R. norvegicus
This species gives birth to 8-12 newborns per litter, which are susceptible to fertilization after 2 to 3 months, often earlier. On average, the female gives birth 7 times a year, with a lifespan that can exceed 12 months.
It has a large sturdy body, with brown hair, slightly black at the top and gray to yellowish white at the bottom. The average body weight for an adult is 300 grams and his body length ranges from 19 to 25cm. Generally, it moves within a radius of 15-30m from the nest.
R. rattus
This species gives birth to 6-10 newborns per litter, with a “maturation” period corresponding to that of R. norvegicus. The female gives birth 6 times a year and the lifespan of the species is similar to that of R. norvegicus.
It has a smaller body than R. norvegicus, with gray to black hair. The average adult body weight is 200 grams and body length 15-22cm. It has a large radius of action ranging from 15-30m from the nest.
M. musculus
Gives 5-6 newborns per birth, with a duration of “maturation” of 1 to 2 months. The female gives birth 8 times a year and the lifespan for this species is 9-12 months. It has a thin and small body, with light brown to light gray hair. The average body weight is 15 grams and body length 6-9cm. It has a small and localized radius of action ranging from 3-6m from the nest.
Health Significance
It is a group of mammals of great importance to humans, which is responsible for a large number of deaths. In addition to Weil Syndrome (leptospirosis), many species of mice are potential carriers of other serious diseases, including salmonellosis, plague, typhoid fever, and some forms of encephalitis. They also cause very serious food infections and allergies while they are carriers of parasites such as mites, nematodes, fungi and insects.
In addition to the above effects on Public Health, symbiotic rodents cause severe damage to electrical and building installations. Rodents can even be responsible for fire in facilities.
Management Ways – Prevention: There should be no openings (eg open windows and doors, open drains, holes in the walls). Particular importance is given to the cleanliness of the area (eg removal of garbage and food sources) and in large outdoor areas (gardens, fields) weed control is applied. Flower beds in contact with the exterior walls of factories and related facilities should be avoided.
Monitoring: The organization and implementation of a comprehensive rodent management program, follows a number of steps, which are:
Space research. Rodents need water, food, shelter (nest) and relative quiet. The research of the space is therefore oriented towards the main points that offer these conditions. With the research the hearths, nests, paths are captured in a blueprint.
Identification of species – Extent of infestation. Investigating these points, after careful observation (feces, footprints, paths, etc.) on the one hand, and after the use of various means of presence control (detection dust, glue traps, mechanical traps, etc.). p.) on the other hand, the species endemic to the area and the extent of the infestation are identified.
Monitoring should take place at regular intervals to detect the presence of symbiotic rodents.
Treatment: For the control of symbiotic rodents, approved bait security stations are used, which are placed in the points – zones that have been imprinted in the area, with special warning, information (product and antidote) marking and inventory of findings exactly at their place of placement. Approved rodenticide baits are placed in the bait stations which are anticoagulants of subacute toxicity that act in the blood (in the prothrombin cycle). These rodenticides baits come in the form of cubes (waxy or not), paste, compacts (pellets, shrimp), ground cereals, seeds and powder.
Particular care is needed when implementing a symbiotic rodent control program in food industries where only presence control measures are taken inside warehouses and on the production site (eg mechanical multiple capture traps), as the use of anticoagulants is not permitted.
Also, the role of the bait station is important and it should consist of hard plastic that does not contain toxic substances, be resistant to ultraviolet radiation, lock securely and have in special places securely attach the bait to prevent it from spreading. The collection and burning or burial of corpses, as well as the collection of the remains of used or baits to be replaced are necessary actions that must be done meticulously, diligently and in a legal manner. In this context, free adhesive surfaces in various parts of production or warehouses are not a test solution as they collect dust and foreign bodies and if a rodent is caught, it is fully exposed and poses a serious microbiological risk. An even worse option is the use of rodenticide baits in bulk, which are a valid chemical hazard and at the same time threaten non-target animals.
