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In this country, blueberries and blackberries not only grow in domestic gardens, but also wild in nature. During a summer walk through the forest we can meet them, patiently waiting for a picking hand. The temptation is great, but so is the hesitation. Wasn't there something about the fox tapeworm? He is said to lurk on the delicious fruits and pose a serious threat to humans. Do we really have to do without a berry treat?
fox tapeworm
The fox tapeworm is a parasite that has chosen the fox as its host, hence its name. Inside the fox it does not pose a risk of transmission, after all it is not part of the human diet. But many people fear infection from wild berries. Does the fox tapeworm spread through berries? You can find out how high the risk of disease really is and how the pathogen spreads in the first place in the following article.
The cycle of reproduction
However, the fox tapeworm, with the scientific name Echinococcus multilocularis, needs an intermediate host for its reproduction: the mouse. In order for the multiplication to take place in the body of the mouse, the pathogen must somehow get from the fox to this small forest and meadow animal. It is transmitted via the fox's droppings.
- Echinococcus multilocularis lays eggs in the fox gut
- Eggs reach the forest or meadow floor via feces
- this contaminates the food of the mouse
- together with grasses and seeds, it also swallows the fox tapeworm
- the larvae continue to develop in it
- the soon weakened mouse is eaten by the fox
- the pathogens have thus reached him again
- the cycle can start all over again
Only when the fox ligament pathogen is outside of its two hosts can it become dangerous for humans and only if the human comes into direct contact with it and then ingests the pathogen through the mouth.
fox population is increasing
In this country, the fox population is steadily recovering, which is equivalent to an increased number of fox farmers. In addition, it is observed more and more frequently that foxes venture as far as the cities in their search for food. This means that the sphere of action of the fox and the sphere of human life overlap. This increases the probability of contact, even if this is not necessarily direct, but can take a detour. For example, when things touched by foxes are touched by people at a later point in time.
course of disease in humans
Fox tapeworms are considered to be the most dangerous parasites for the human body in Europe. It can take up to 10 years for the infection to become noticeable.
- untreated infections lead to death
- Drugs cannot kill the worm
- only to curb proliferation
- Medications have strong side effects
- and are mandatory for life
With this frightening scenario, it is not surprising that the consumption of wild berries has always been discouraged. Blueberries, blackberries and Co. from the forest, the home of the fox, were assumed to be the main carriers of the parasites.
disease risk
But what about the actual risk of disease for humans? The perceived threat is contrasted with clearly documented facts and figures. The renowned Robert Koch Institute has determined the following data for Germany and the year 2015:
- 45 people out of approx. 82,000,000 Germans were infected
- this corresponds to a risk ratio of around 0.00005%
- Transmission sources could not be identified
For all the dangers feared in this country, including the danger of being struck by lightning, this is one of the lowest and therefore most improbable risks of all. And this despite the fact that the diseases have increased compared to previous years. However, this is not because the pathogen itself has become more dangerous, but because of the increased number of infected foxes.
Not every contact with the pathogen is momentous
Independently conducted studies from several countries assume that a person must have regularly or a large number of pathogens in order to be infected. It would have to be hundreds or even thousands of pathogens. Furthermore, there is evidence that the majority of the European population, despite having been in contact with the pathogen - proven by educated antibody - not ill, to a certain extent has a resistance. We are talking about 80 to 90% of the total population.
Regions with increased risk
Statisticians have evaluated the number of cases and point to southern states an increased risk of disease. Bavaria and Baden-Württemberg are ahead, followed by Hesse and North Rhine-Westphalia. This may not least be due to the spread of the fox and the landscape conditions where more edible plants grow wild.
tip: Not only berries could carry the fox tapeworm, also the low-growing wild garlic popular with pickers and many other edible herbs could theoretically be infected in fox regions.
The home garden is almost certain
Although the all-clear has long been given for wild berries, some garden owners fear a threat to their cultivated specimens. But this concern is unfounded. The fruits hanging high on the branches would hardly come into contact with the droppings excreted by the foxes on the ground. In addition, the forest dwellers are extremely rare visitors to a cultivated garden.
Unless you have your yard unfenced and near a forest infested with foxes, the risk of the berries you harvest carrying fox ligament pathogens should be virtually nil.
transmission
Forest berries as disease vectors
But is it actually the snacking on the delicious forest berries that has led to these few diseases? From generation to generation, the risk of infection that wild berries are said to pose was passed on as supposed knowledge and was intended to act as a deterrent. And indeed, to be on the safe side, many people refrain from enjoying the fruits of the forest.
A few decades and a few scientific investigations later, this old assumption has not been confirmed. On the contrary, scientists today assume that from the bramble bushes and their related shrubs hardly any danger can go out. Wild berries don't lie on the ground but hang high in the branches, well away from any fox droppings.
Strawberry fields, the greater danger
If anything, the low-growing strawberries represent the greater risk of infection of all berry varieties. The intermediate hosts, mice, like to hide in strawberry fields and could thus transmit the pathogen to the strawberries.
Likely routes of transmission
It has been found that hunters and farmers are more often infected by this pathogen. Presumably because they regularly come into contact with forest and meadow soil. This affects more than half of all cases of infection.
Another group are the dog owners, especially if their dogs are allowed to roam freely. On their forays they catch infected mice and infect themselves with the tapeworm. An infected dog spreads as many pathogens through its faeces as a sick fox.
- Pathogens can also get into the dog's fur
- and by stroking people's hands
- if there is a lack of hygiene, there is a risk of infection
Incidentally, sick cats pose a smaller risk, as they themselves spread fewer pathogens than dogs.
tip: Dog owners who spend a lot of time outdoors with their animal should think about regular deworming for their four-legged friend.
Tips for the security conscious
If you also want to further minimize the remaining risk associated with the consumption of raspberries, blackberries and Co., you can heed the following tips:
- Always wash your hands thoroughly after spending time in the forest or meadow
- only pick wild berries that hang higher than 80 cm
- preferably only in fox-free areas
- do not eat unwashed fruit from the bush
- Wash fruit several times at home
tip: The fox marks its territory with its droppings. To do this, he chooses striking places such as rocks, hilltops, tree stumps or crossroads. In fox areas, such places should therefore be excluded as collection points for wild berries in order to avoid any transmission of the pathogen.
Heat destroys the fox tapeworm
Simply prepare delicious jams from the berries. The heat from cooking kills the pathogens from as little as 70 degrees Celsius. Cold, on the other hand, does no damage to the fox band. Therefore, while freezing berries in the freezer is a possible method of preservation, it is by no means an effective measure against fox tapeworm.
