Impending onslaught of norway rats

Threatening onslaught of Norway rats

Image: Earth’sbuddy / CC-BY-SA-3.0

Rat control is a mabig successful eternity task. Due to warm winters and severe drought, the population spreads, and at the same time they develop resistance to available poisons


Rats are the most widespread small rodents in the world and the most successful cultural predator. In London, the rats made themselves at home in June 2019, even in the time-honored Buckingham Palace and the parliamentary seat of Westminster. The con "was not amused". While her majesty’s exterminators were busy preparing the exitus for the British rats, the deputies one floor above were debating the political "Brexit".

Rats belong to the family of long-tailed mice. There are about 65 species worldwide. In addition, there are individual species whose existence is known, but which have not yet been scientifically recorded and described. Two species of rats live in Europe: the domestic rat (Rattus rattus) and the Norway rat (Rattus norvegicus). Both have beady eyes and brown-gray fur.

The Norway rat has a stocky body with a head-torso length of 8-30 centimeters and a naked tail of 14-22 centimeters. Adult animals can reach a weight of up to 500 grams. The domestic rat is slightly smaller. It grows only 16-20 centimeters in length, but has a longer tail of 19-25 centimeters. The so-called laboratory or colored rat is a domesticated breeding version of the Norway rat, which is kept by its owners as a pet. The sense of smell of these rodents is well developed, their sense of obedience reaches the ultrasonic range.

Threatening onslaught of Norway rats

Norway rat. Image: Reg Mckenna / CC-BY-2.0

Rats are smart and social animals. The better-studied, culture-following species live in groups of up to 60 animals, with group members recognizing each other by scent. Groups are composed of one or more males and several females, both sexes establish a hierarchy. They are territorial animals, the territories are defended against intruders.

Both species of rats originated in Southeast Asia. The domestic rat arrived in Central Europe two thousand years ago with the Roman settlement; the Norway rat arrived at the beginning of the 18th century. The game originated in Russia at the end of the nineteenth century and spread to Europe. In the meantime she has driven out the house rat, so that the latter is almost extinct.


Rats are basically omnivores. They eat everything that humans eat, plus soap, paper, beeswax, fur, etc.. In early 2018, for example, rats invaded the University Library in Stuttgart and nibbled at the books there: 200 shelf meters were so filthy with rat droppings that they had to be disposed of, nearly 8.000 books were destroyed. The invaders preferred the social, economic and legal literature from the sixties to the eighties of the 20th century. Century. The damage amounted to about 200.000 euros. The fight decrease lasted three quarters of a year. So much "Education hunger" is rather rare.

Species living in the vicinity of humans often find their food in storage facilities, in fields or in garbage. They feed from unsecured compost heaps, garbage bags, etc.. A consumer society that throws away 18 million tons of food every year should not complain about the spread of rats.

Species living in nature prefer mostly seeds, grains, nuts and fruits, but supplement the diet with insects and other small animals. Norway rats are mainly carnivores, their prey includes birds and their eggs, small mammals and other vertebrates, but also fish.

Propagation and multiplication

(Sewer) rats live in the underground sewage system of cities and towns. They love construction ruins, rubble, clutter and bushes, if it offers them shelter and sufficient food.

Rats have various biological characteristics that require them to spread:

  • They can make themselves amazingly narrow, which helps them conquer living spaces. Where a rat’s head fits through, so does the whole rat.
  • Because they are so mobile, rats can go almost everywhere.
  • You can dig very well.
  • They are adept at climbing and moving vertically up walls and tubes, sometimes emerging from an upper floor through a toilet bowl.
  • You can dive for up to three minutes and swim continuously for three days.
  • As omnivores, rats can inhabit any habitat they like.

To their spreading contributes in particular their high reproduction rate: Within a pack, the females are all fertile at the same time. Female rats throw six to eight rats per litter. They usually need three to four weeks before they are independent. Norway rats become sexually mature themselves from the age of three months, domestic rats after three to five months. Because of the short birth cycle and the rapid sexual maturity of the young, a pack of rats can multiply very quickly if left unattended. If a sufficiently coarse food supply is available, there are only a few limiting factors. Thus, a considerable infestation can quickly arise, which must be specifically combated.

In real rat life, a female produces about 500 children and offspring per year; theoretically, a Norway rat can produce as many as 1.Generate 952 descendants.

How many rats live in Germany is not known. There is simply a lack of valid data, as it is methodologically not possible to record the population in a coarse area at all. Thus, rats form a gnawing, pernicious underground army of invisible, nocturnal fugitives, and many inhabitants like it that way, so that they notice as little as possible of the rats.

Impending onslaught of Norway rats

Four-day-old wandering rats. Image: Alexey Krasavin / CC-BY-SA-2.0

Instead of giving an absolute number for the rat population, one usually helps oneself by stating how many rats live in a certain area in comparison to the number of humans. Often it is said that the ratio is 1:1. However, the "Mirror" indicates that this outdated figure is quite arbitrary and had historical causes:

Moreover, the rumor persists that there is one rat per inhabitant in a city. For Berlin this would mean more than 3.7 million rats, for Hamburg at least 1.8 million. However, this theory is based on an investigation that is more than a hundred years old. In 1909, the British explorer William Richard Boelter estimated that there is one rat per acre (4047 square meters). Great Britain at the time was 40 million acres in size and happened to have 40 million inhabitants. Hence the thesis one rat per inhabitant.

Others estimate that there are twice as many rats as people, or 2:1. Some people say that on average there are 1 to 1.5 rats for every person in the country, and in the big cities the ratio is 2 to 2.5 to 1. Other treasures are still much higher, but can neither be confirmed nor denied. Pest control companies ame a population of 150 to 200 million Norway rats in Germany. Others quote a figure of 300.000.000 animals.

In contrast, the number of rat sightings reported to authorities is by no means a measure of the actual gross dimension of rat occurrence. Twice a year, the number of sightings increases seasonally: In spring, the rats are lured by the increased temperatures from the warm underground sewer system to the ground surface, where they seek new shelter in parks and ruins. When the weather gets colder in autumn, the rats return to the sewage system via public roads. Otherwise, the shy wild animals seem to have disappeared.

Half of the world’s population already lives in urban areas, and this proportion is expected to rise to 60 percent by 2030, which means that the number of brown rats – according to this calculation – will also increase.

Increased occurrence or even plague of rats?

The spread of rats depends not least on climatic and environmental conditions. Due to the warm winters of 2017/18 and 2018/19, the "Natural selection" from. Even old and sick animals survived the winter time. In addition, it was relatively dry, so no rats drowned in the flooded sewage pits during high tide. Instead, the populations grew and spread, a phenomenon that can be expected more often in the future.

Since the subject "Rats" is connoted with disgust, fear and taboos, the city authorities and city hall parties tend to dismiss it in order to avoid damage to the image of their municipality. Only in exceptional cases, when the problem can no longer be concealed, is a localized "Plague of rats" states. At least a slight increase in rat infestation has been observed in the last two years. The Ruhr area is particularly affected as an urban coarse area with numerous industrial ruins and water bodies, but other cities are also affected. So in Berlin the Schadlingsbekampfer in 2018 had to send a total of 11.414 times, which was an increase of 14 percent compared to the previous year. "Almost every city has problems with rats", confesses Thomas Guske, chairman of the NRW state association of pest exterminators

  • Ahlen (52.582 inhabitants on 31.12.2018): While there were 29 officially registered sightings in both 2017 and 2018, there were already 22 traps in the first half of 2019. For rat control in the local sewage system, the city spends annually 50.000 euros to.
  • Bielefeld (333.786 inhabitants): At the beginning of 2019, there was an increased incidence of rats in the allotment garden colony in Bielefeld-Sennestadt in the area of Lahnweg, Naheweg and Wurttemberger Allee, as well as in the south around Innstrabe and Illerweg. The animals were apparently attracted by the compost heaps and wrong animal feedings. In the local hardware store the rat traps were nearly sold out.
  • Bonn (327.258 inhabitants): In 2018, experts came to the conclusion that up to five rats per inhabitant lived in the old federal capital, which corresponded to a total population of ca. 1,5 million animals. Particularly affected are the districts of Bad Godesberg, with the old government quarter, Beuel, as well as the banks of the Rhine and the Hofgarten, and the streets Max-Planck, Kortrijker, Mallwitz and Paracelsus. Even the headquarters of the professional fire department at Lievelingsweg 112 was affected at the end of 2018. For rat control the city spends annually only 25.000 euros from.
  • Dinslaken (67.525 inhabitants): In Dinslaken-Hiesfeld was affected in June/July 2019 year in particular the Aubenbereich of the municipal Kindertagesstatte in the Riemenschneiderstrabe. The daycare center decided not to inform the parents or guardians of the children about the rat presence at first, after consultation with the responsible department for child and youth welfare at the city, city spokesman Thomas Pieperhoff admitted. "We have done our due diligence in this case. (…) The nursery management does not have to inform the parents in this case."
  • Dorsten (74.736 inhabitants): In mid-December 2014, a rat caused a short circuit in a 10 Kv power station between the districts of Wulfen and Lembeck by biting a cable. As a result, the power went out in several hundred houses in Alt-Wulfen, and in the neighboring district of Barkenberg there was temporarily no Internet or television reception.
  • Dortmund (587.010 residents): In 2016, the Dortmund city sanitation department announced that for every inhabitant there were six rats. In the middle of March 2018, the daycare center St. Apostles in the northern city of Dortmund to be cleared. The city calls its citizens once a year to a concerted rat-fighting action. "To curb the rat infestation in Dortmund, the city calls for a joint combat action in February. (…) From 14. until 28. February (2019, G. P.), the city of Dortmund wants to make it uncomfortable for the pests – and calls for a joint combat action. (…) Everybody who is obliged to fight rats can decide for himself how to proceed."
  • Duisburg (498.590 inhabitants): In Duisburg-Homberg was in May 2019 the four-star hotel "Rheingarten" concerned. A pack of rats feasted on the hotel’s mull. "Rat population explodes", explained a local resident.
  • Ennepetal (30.075 inhabitants): There has been a rat problem behind the hardware store on Neustrabe since fall 2017. The animals live in the slope there and come out of their holes only in the morning and evening. Initially, the city administration amed that the problem would be solved in a few weeks: The location for the rubbish containers was regularly cleaned, question markers laid out. However, several sabotaged "Animal Protectors" the hygiene inspection. They deliberately put out fruit and other goodies to attract the rats. "Feeding actively prevents the successful control of the pests," lamented the city press spokesman Hans-Gunther Adrian. "The population is at least dammed up. But we do not know if it will be possible to eliminate them completely."
  • Gelsenkirchen (260.654 inhabitants): In the Rotthausen district, residents complained in June 2019 about an increased incidence of rats around the local savings bank. From the 11.000 sewage pits in the urban area will be 5.000 drains are filled with coders every spring by the operator Gelsenwasser.
  • Hamm (179.111 inhabitants): Ulrich Witzig, the only remaining pest exterminator in Hamm, estimates that there are usually two rats per resident, though the rat population has increased even more since 2018. In the western part of Hammer, at the corner of Worthstrabe and Langer Strabe, an entire apartment building had been massively infested for several years. The owner had let her house from the ground time slowly decay, while she continued to cash in with migrants from Sudosteuropa. When more and more neighbors complained, employees of the environmental agency took a look at the house in July 2019, but were not allowed to enter it – for legal reasons – in order to carry out a proper inspection. Instead, all they could do was write to the owner and ask her to take remedial action. In addition, the city was able to set up rat traps on neighboring properties. Beneath the city’s territory lie 800 kilometers of sewers with around 25.000 pits, which are inspected at least once a year by the responsible Lippeverband (Lippe Association).
  • Holzwickede (17.118 inhabitants): In the press it hieb in June 2019: "In Holzwickede there was a real rat plague. The municipality has taken measures. Now they are asking the citizens of Burger for help." Rat encoding stations were set up at Emscherpark and at the P+R parking lot at the main train station.
  • Koln (1.085.664 inhabitants): In view of a massive rat infestation in the classrooms, the cake area and the schoolyard, the two elementary schools Ernst-Moritz-Arndt-Schule and Grungurtelschule in Koln-Rodenkirchen (Mainstrabe) had to be closed from 10. up to 12. April 2019 to be closed so that professional rat control could be carried out. Some 800 schoolchildren were affected. The school administrators informed the parents: "We cannot justify the situation like this. Therefore, for hygienic reasons and to protect your children, we have decided to suspend school operations."
  • Krefeld (227.020 inhabitants): There were heated arguments in the city council in September 2016 about how many rats live in the city. The SPD parliamentary group ames a total population of around 1.000.000 animals, while the other parties put the figure at 600.000 to 1.000.000 figured. The head of the public order office, Georg Lieser, objected: "General complaint situation does not indicate increased rat problem. Information on a total population of rats in Krefeld is not available to the administration and Netzgesellschaft Niederrhein." Particularly affected were the old Gladbecker Strabe, the Westwall, the Vagedesstrabe at Friedrichsplatz and most recently the Moritzplatz. In September 2019, there was an increased incidence of rats around the Helios clinic.
  • Marl (83.941 inhabitants): In Marl, a rat caused a short circuit in the basement of the city hall on 7. October 2019 by cable bite a short circuit in the cellar of the city hall. The computer system failed. Two days the city government had to stop its work. This was the third rat attack on City Hall, following 2016 and 2018.
  • Schwerte (46.340 inhabitants): In the spring of 2015, rats spread from a railroad yard and also invaded private homes around Robert Koch Street. Attempts by the city to contain the infestation failed because the animals kept finding refuge along the railroad embankment. The prere of the neighbors on the city increased because animals kept gnawing through doors and also appeared in the residential buildings. It was not until the city joined forces with the railroad company to combat the infestation at the beginning of 2016 that the rat population could be contained. In addition, the vegetation along the railroad embankment was cleared, thus ensuring that there was no longer any possibility of retreat. Then a contracted company laid out poison coders.
  • Unna (58.633 inhabitants): The playground in Salinenstrabe in the Konigsborn district has been shut down since 2014 because pest controllers simply can’t get a handle on the rat problem there. The duration of the rat control measures there was – to a certain extent – on the edge of the permissible. Also the garden suburb in the south of Unna has a rat problem. The city’s wastewater operator began on 12. August 2019 with laying out coders in its canal system. Due to the coarseness of the network, the action lasts until October. (…)

Health hazards

Rats are pests of supplies and materials. Causing frass damage and contamination of food in cakes, basements and storage rooms. In addition, rats can gnaw on electric cables and cause fires, but they can also destroy sewage pipes, beams, boards, furniture and doors. Whereas in the past, stoneware pipes were used to build houses, nowadays plastic pipes are used. They are cheaper, lighter and therefore more manageable for the builders. However, the plastic pipes have a decisive disadvantage, which was noticed only in the course of the time: At the transition and bending points there are sharp edges, which are nibbled with pleasure by the rats. They dig a hole in the pipe and create a breeding ground there by simply washing away the shoveled sand with the sewage. In this way, the rats can spread more easily inside and outside the buildings. Last but not least, the rats cause a considerable odor pollution, as each Norway rat produces about 2.000 excrement balls.

Even more serious than the economic damage are the health risks posed by rats. rats transmit disease germs as so-called vectors or serve them as reservoirs. The various species of rats can directly or indirectly transmit about 120 different infectious diseases worldwide, and some of these infections are also widespread in Europe. Only in rare extreme cases, such as in times of war, do rats attack people who are injured or defenseless, or when the rat feels threatened and has no means of escape.

Rodents transmit the following infectious diseases to humans, among others: Tapeworms Hymenolepis diminuta but also the dwarf tapeworm (lat. Hymenolepis nana), the "only" reaches a length of 4 to 9 centimeters,

  • Cholera (Vibrio cholerae or Vibrio el Tor),
  • spotted fever (Rickettsia prowazekii),
  • Hanta (Hantaviridae, such as z. B. the Puumala virus),
  • Hepatitis E (HEV)
  • Leptospirosis (about 200 different, bacterial serotypes of the genus Leptospira), especially "Morbus Weil" by Leptospira interrogans,
  • Plague (Yersinia pestis.),
  • Rat Bite Fever (RBF) (Streptobacillus moniliformis), u. a. Haverhill fever,
  • Dysentery (Entamoeba histolytica),
  • Salmonellosis like z. B. Paratyphoid fever (Salmonella Typhi),
  • SARS (Coronavirus SARS-CoV),
  • Sodoku (Spirillium minus),
  • Rabies (Lyssavirus)
  • Toxoplasmosis (protozoa Toxoplasma gondii),
  • trichinosis (Trichinella spiralis),
  • Tuberculosis (especially Mycobacterium tuberculosis),
  • Tularaemia (Francisella tularensis),
  • Typhoid fever (Salmonella typhi),
  • (…)

This gathering can be understood only as a current snapshot. New human pathogens or pathogen subtypes are constantly being detected in rodents, emphasizes the Lower Saxony State Office for Consumer Protection and Food Safety. (LAVES) in Oldenburg.

Of the diseases mentioned, Hanta fever and leptospirosis in particular pose a real threat in Germany today: Hanta hamorrhagic fever is mostly transmitted by (red) mice, but also by rats. Transmission to humans is mostly respiratory through the respiratory tract, sometimes orally through the mouth, occasionally through contact infection, such as rodent bites. The incubation period is between 5 and 60 days, depending on the virus type. Symptoms include abrupt onset of fever, headache, aching limbs, drop in blood prere, visual disturbances and temporary kidney damage. The disease is usually cured without consequences. About 1-2 percent of the German population has hantavirus-specific antibodies. However, the number of reported cases is far lower, which indicates that the infection often occurs without clinical symptoms, but also that clinical symptoms (kidney damage) are not always thought to be caused by an infectious agent. In 2016, 282 cases were recorded nationwide, whereas in 2017, 1731 persons were recorded, and in 2018 again "only" 235 infected persons.

Leptospirosis is the most dangerous infectious disease for humans transmitted by rat feces or urine. In about 90 percent of the cases, leptospirosis runs similar to the flu: fever, chills, headache and aching limbs. The disease can last up to forty days. It is recognized as an occupational disease among sewer workers. But it occurs only rarely in Germany: in 2018, just 117 traps were reported.

Threat of an onslaught of Norway rats

rat droppings in the basement of an apartment building. Image: © Túrelio / CC-BY-SA-3.0

Canal and forest workers serve bio-medical research as "guinea pigs". Furthermore, rats are also reservoirs of pathogens in the field. These pathogens can be transmitted by ticks and fleas (z. B. Xenopsylla cheopis) can be transferred to humans and animals (z.B. Borrelia burgdorferi). They also carry animal diseases such as foot-and-mouth disease (FMD), avian influenza, cowpox and swine fever.

Recently the rats are also infected with multi-resistant pathogens. In Berlin, 13.6 percent of the rats tested are infected. In the Austrian capital Vienna, it was proven in 2016/17 that 14.5 percent of the rats caught were infected with multiresistant enterobacteria, and 59.7 percent were colonized with multiresistant staphylococci. "In 9 of the 62 rats, 8 multidrug-resistant Escherichia coli and two Enterobacter were found with the furrowed NDM-1 resistance, against which many antibiotics remain ineffective", wrote in the arzteblatt.

The research project involved the Freie Universitat Berlin and the Verein "InfectoGnostics research campus Jena e. V." at the University of Jena were involved. However, little is known about the exact role of rats in the epidemiology of multidrug-resistant germs. In view of the patchy state of research, Prof. Dr. Rainer G. Ulrich, laboratory director at the Institute for New and Novel Animal Pathogens (INN) at the Friedrich Loffler Institute (FLI) on the island of Riems near Greifswald no mincing his words. In an interview with the "ZDF" he explained in mid-2017:

At the moment the state of affairs is that we have no monitoring system, but we have practically no information or little information about the pathogens that are present in rats. We would like to have data on rats from different habitats, for example from urban areas, from zoological gardens, from farms. We needed systematic studies, we needed studies that would look at zoonotic pathogens naturally, that is, pathogens that are transmitted from rats to humans. But we are also interested in pathogens that are rat-specific pathogens, because on the basis of these pathogens we can possibly develop new animal models for corresponding pathogens that are related to the rat-specific pathogens.

Due to population growth and increasing urbanization, the spread of rat populations and the penetration of tropical infectious diseases into hitherto temperate climate zones as a result of global warming, scientists ame that health hazards will increase in the future: "Dense human population, increasing interaction with urban wildlife and warmer urban microclimate favor the emergence of diseases transmitted from wild animals to humans", explained the researchers.

Rat control

Cities and towns provide similar rat infestation prevention tips on their respective local websites:

  • pay attention to cleanliness and tidiness of the building,
  • Avoid bird/feeder houses at all times of the year, do not overfeed wildlife,
  • Do not leave pet bowls outdoors or in the open. remove draughty after feeding,
  • do not dispose of food scraps in the toilet,
  • keep gauze areas clean and closed, have defective garbage cans replaced,
  • Throw cake garbage in the trash can only in closed plastic bags,
  • put out gauze bags only on collection day,
  • not to use plastic trash cans as a substitute for a trash can,
  • do not throw away fast food into the nature,
  • Do not dispose of meat or bone remains in compost piles,
  • do not feed ducks in public parks,
  • bushes, shrubs and ground cover should be cut back regularly, if possible in such a way that they do not offer any hiding places, this also applies to burial grounds,
  • Checking of sewage systems for possible damage, building damage. damage, building damage (tower gaps and cracks) and defective house connections must be repaired, unbarred cellar windows must be closed.

The biological life expectancy of a rat is very limited. A house rat lives only one year, a Norway rat can theoretically live two years, but due to active rat control and various predators, even Norway rats in urban areas rarely live more than one year.

The natural enemies of rats in urban areas are (domestic) cats and dogs, as long as they are not completely degenerate. In nature resp. in rural areas rats are hunted by foxes, stone martens, golden eagles, eagle owls and tawny owls. Where rats appear in the human environment, they must be fought as soon as possible, because they do not disappear by themselves. Due to their social intelligence, rats are much more difficult to catch than mice. They occur in family bonds and learn from the fate of their family members. Their pack formation makes them difficult to control. A captured rat keeps contact with its "Relatives" and gives them the understanding that there is a danger connected with this or that apparatus. The use of live traps, which are simply a cruder version of mousetraps, therefore catches fewer of the rats present than deadly percussion traps, which use a bolt to shatter the animal’s skull and spine. As part of the mechanical control, the access routes to the infested cellar, barn or storage room must be blocked in any case to prevent a further infestation in advance.

imminent onslaught of Norway rats

Rat caught in a beating trap. Image: Ramon Susqueda / Public Domain

The killing of rats with the help of poisonous coders is by far the most widespread method of rat control in industrialized countries. The legal basis for their use is the EU Biocide Regulation no. 528/2012 of 1. September 2013. The poisons are. d. R. To rodenticides. The poisons of the so-called "First generation" (first-generation anticoagulant rodenticides – FGAR), such as. B. Warfarin, are considered obsolete and are used only by private individuals; the agents currently used by professional pest controllers belong to the category of "second generation" (SGAR) or "third generation" (TGAR) to. The disadvantage of these more modern poisons is that they degrade very slowly in the environment.

Threatening onslaught of Norway rats

Cardboard box with rat poison coder. Image: © Túrelio / CC-BY-SA-3.0

Rat poisons such as z. B. Bromadiolone, difenacoum or flocoumafen, etc. contain the active ingredient 4-hydroxycoumarins. This substance stops blood clotting. Such an anticoagulant causes the animals to die within three days. Wikipedia states:

The behavior mentioned since about 1954, that rats were supposed to send out a taster with every new food offer to test the food for contractibility, is a misinterpretation of the natural social and eating behavior of rats. Rats exhibit very complex behaviors when eating, for example, to avoid food phobias that could prevent or restrict the acquisition of new food reserves. Unknown food – in nature there is little highly toxic food, but potentially nutritious material, occasionally bacterial or viral or otherwise contaminated – is often eaten first by curious and inexperienced young animals and in most cases is harmless and without negative consequences for the animal. But as social animals, rats generally perceive each other, also during and after feeding behavior, and well-being, or unusual behavior, or in extreme cases death – possibly associated with a certain odor, is accordingly registered either positively (reinforcing) or negatively (warning), which is why rat poisons have been developed in such a way that their lethal effect manifests itself only long after feeding (time-delayed effect, second generation rodenticides).

The coders contain u. a. Oatmeal or corn, look like soaps and are supposed to taste sublich, this attracts the rats. When it gets cold, the rats have to eat fat, then the pest controllers prefer to use coders with a high fat content. For the protection of other animals, the poison is laid out as a pellet, paste or pressed block in special plastic koderboxes.

Usually, a follow-up inspection takes place two to four weeks after the first occupation action with coders. Where coders are gnawed on, they are replenished in a process known as pulse gnawing. Thus, a successful control decrease extends to approx. six weeks, below that it cannot be done. Warning signs must be posted to alert residents to the presence of the poison. Long-term permanent poisoning is now forbidden by law or. only in exceptional cases "in case of increased risk of infestation" still allowed. It is recommended to burn the killed rats, otherwise other animals could eat them and get poisoned as well.

However, some of the rats become immune to the poison over time, in which case the poison merely serves as a welcome food for the rats. In the long term, this could affect a total of five first- or second-generation toxins (chlorphacinone, coumatetralyl, bromadiolone, difenacoum and warfarin). Another factor contributing to immunization was the fact that in earlier years many private homeowners misused the available toxic products. Resistance areas are now considered to be northwestern Germany (southern Emsland with the county of Bentheim and the Cloppenburg-Vechta area), several large cities (Berlin, Frankfurt, Hanover and Stuttgart) and several cities in the Ruhr area (Herne, Herten, Lunen, Wesseling, etc).). high doses of poisons have been banned, which in turn has had negative consequences, such as the "ZDF" reported:

Pest fighters complain that hunting rats is becoming more and more complicated. One reason is an EU regulation that was actually well-intentioned: It was intended to prevent too much rat poison from being released into the environment and to prevent humans and other animals from being endangered by the poison. The problem: Before the regulation, pest fighters could make their own poison coders, using fresh materials such as apples. Now prefabricated coders are prescribed, which are often less attractive for the rats. This prolongs the fight and makes it more expensive. In addition, the poisons must now be shielded in some cases, for example by construction fences. An extra cost.

In the Federal Republic of Germany, around 870 metric tons of small doses of poisonous coders are used against rodents every year.

The poisons are also dangerous for pets and other non-target animals. They are therefore only laid out in coder boxes. A domestic cat does not have to have eaten the poison itself, it is sufficient if it has eaten a mouse or rat that had ingested the poison shortly beforehand. One speaks then of a "secondary poisoning". In the event of poisoning, vitamin K serves as an antidote.

The rat poisons used in the coders are also mostly harmful to human health, and rarely poisonous (hazardous substance labeling) "T"). Therefore, special care must be taken when using and handling them, especially with regard to possible rats. in the same house resp. Environment living infants who put everything in their mouths. Particularly fatal is that the toxic effect is delayed and the symptoms are often not associated as a contamination with rat poison. Bleeding gums, mudiness and bloody vomiting sometimes take days to appear, and in adults it can even take months for the symptoms to appear.

In addition to the rodenticides mentioned above, fumigants (e.g. B. carbon dioxide, hydrogencyanide or aluminum phosphide) used in the. This can temporarily kill about 95 percent of a population in the short term.

Despite decades of efforts to decimate the rats, one thing is certain: they will never be completely eradicated. The veterinarian Dr. Henning Wilts from Landau predicted:

I think cockroaches and rats are the last to populate the world. Simply because they can adapt very quickly to different living conditions – be it radiation, pesticides, toxins, some of which we don’t cope with as well as the rats.

Authorities jungle and competence wrangling

Rat extermination costs money and therefore the question arises, who pays?? In view of the costs and the financial shortage of many municipalities for years, this is not an insignificant question. The answer depends first of all on where the rat infestation was found – on public or on private property.

Private persons are allowed to use first generation poisons (chlorophacinone, warfarin, etc.) available in specialized shops and approved for this use, provided that the instructions for use and the appropriate precautions are observed.) apply in or around buildings, but not in open areas. Since 2012/2013, more potent rat poisons (difenacoum, brodifacoum, etc) are allowed.) can be used only by professional pest controllers in buildings or in open areas. Residual toxic waste must be disposed of as special waste.

Commercial owners of houses or land are fully responsible for the control of rats according to the Law on Protection against Infection and have to bear the costs themselves. If only bait is needed, it can be purchased for a few euros at a pharmacy, hardware store or seed shop. The use of a professional pest controller costs about 100 to 150 euros: However, if the rats have dug tunnels that loosen the slabs on the Burgersteig, so that passers-by are in danger of falling and more extensive excavation work has to be carried out, a few thousand euros can quickly be added up at today’s tradesmen’s prices. If homeowners do not comply with their obligation to control rats, the public order authorities can threaten to carry out compulsory administrative measures. Within the framework of this substitute performance, the city then commissions a damage-fighting company to carry out the necessary removal work and then collects the costs from the house owner via the judicial treasury.

Then the dispute begins as to whether the affected part of the Burgersteig is on public or private property. In the case of house entrances and street corners this is not always clearly recognizable. Here only a look at the relevant maps at the cadastral office can help. Damage to the underground sewage system can lead to a further dispute: The municipal sewage disposal company is responsible for the constant infestation of rats in the combined sewage system (sewage and rainwater), and routinely hangs poisonous coders on the ladders of selected manholes once or twice a year. To avoid resistance, a different toxicant is used each year. However, for the underground supply lines from the combined sewer to the residential houses and industrial buildings, the owners are solely responsible, even if these supply lines are not clearly visible. T. run under the public sidewalk and are not accessible at all. If damage or loss occurs here. If there is an infestation of rats, which eventually appears on the surface of the ground, the owners of the houses have to pay for the control of the sewer rats themselves. In this way the city keeps itself harmless and passes on all costs to the individual citizen and taxpayer.

In addition, in the event of a rat infestation on public land, different municipal authorities may be responsible. The municipal land office is responsible, if a park or children’s playground is affected. The Environmental Office intervenes when an increased rat population is detected in the area of (wild) rubbish dumps. The Civil Engineering Office intervenes if rats have broken out of the underground sewer system and dug tunnels under the Burgersteigen, which threaten the traffic safety of pedestrians. For routine rat control in the local sewage system, the municipal or supra-regional sewage association is responsible. Eventually, the city’s public order department also gets involved when, in the cases mentioned above, the "public safety" is threatened.

However, the authorities only record the infestation, the practical fight was outsourced years ago to commercial pest control companies. However "pest fighter" not protected by law, therefore any animal torturer can call himself so. Thus, only about half of the companies are members of the German Schadlingsbekampfer-Verband e. V. (DSV) based in Essen, Germany:

Only companies that meet the high legal requirements for pest control in Germany (the highest requirements in Europe) can be accepted into the DSV. The professionalism of a company can be recognized, among other characteristics, by a CEPA-Certified certificate (CEPA = Confederation of European Pest Management Associations, G. P.). Especially in this sensitive area, the member companies of the DSV feel responsible for a high level of consumer protection and are supported by association inspections, e.g. by the German Association for the Protection of Consumers (DSV). B. supported by constant information from professional journals, training and further education and other activities for quality arance and improvement.

The training to become a pest fighter takes three years; it is not only "a job with a perspective", but a "profession of passion" for people who "Desire for daily changing requirements" have, the association proclaims.

However, this capitalist rat race exclusively by private companies is now reaching its limits: Due to the general shortage of craftsmen, only one pest exterminator with a biocide certificate is available in some cities. Since "pest fighter" In addition to the fact that being a vermin exterminator is not a profitable profession in youth circles, there is a shortage of young people, so that in the foreseeable future some cities will not have a single vermin expert left: While the number of rats will increase, the number of rat fighters will decrease. To remedy the situation, unemployed academics have to be retrained as career changers. However, talented literary scholars who are wonderful work interpretations about the tragicomedy "The rats" by Gerhart Hauptmann, probably unsuitable for practical rat-fighting and much too sensitive.

After the rat population has already increased in the last two years, it remains to be seen how the rats will continue to spread in the coming years under the changed climate and weather conditions. Even the city of Hamelin (57.510 inhabitants incl. Children) has long ceased to be a rat-free zone.

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