Trichinoscopes are microscopes that were specifically designed to diagnose trichinella, the presence of the parasite Trichinella spiralis in muscle tissue samples of animals that are the basis of food for humans.
Also known as trichinellosis, it is a parasitic disease caused by eating undercooked meat and containing cysts (larvae or immature worms) of Trichinella spiralis. This parasite can be found in the meat of animals such as pig, horse, wild boar, deer and rat.
It is a common infection in the world and it was very frequent in the past. When a person eats meat from an infected animal, trichina cysts, present in the meat, hatch in the intestines and grow into adult nematodes. Nematodes produce other worms that migrate through the intestinal wall into the bloodstream. The worms invade muscle tissues, which include the heart and diaphragm. They can also affect the lungs and brain. Cysts stay alive for years. Trichinosis symptoms include: abdominal discomfort, spasms, diarrhea, facial edema, fever, and especially muscle aches.
The signs, symptoms and their severity vary according to the number of larvae that were consumed with the infected meat. It is a self-limited disease but it can present complications.
Diagnosis of trichinosis
It is performed by direct examination, through microscopic examination of the animal’s muscle tissue. Usually samples from the tongue, diaphragm, and intercostal muscles. These are compressed between two elongated slides that allow multiple samples to be studied at the same time.
It is a not very sensitive method, although it is useful in cases of large infestation. A previous digestion test is also performed. Currently, microscopic observation is carried out on the sediment of tissues previously digested in the laboratory. The European standard that establishes this diagnosis is 2015/1375.
History of trichinosis
The famous German scientist Rudolf Virchow (1821-1902) proposed in 1870 that the diagnosis of trichina should be carried out by microscopy in meat destined for consumption, especially pork and wild boar. This proposal, when accepted, determined that there was a great demand for microscopes in the German states and later in all European and American countries.
Since the parasite cysts are relatively large in size, a low magnification objective is required under the microscope. At the same time, it is a diagnosis that must be made quickly and sometimes near or in the slaughterhouses themselves.
All this determined that the microscope that was designed for this purpose was a simple, strong, low-magnification device, with natural lighting and cheap. They are characterized by being small in size, not tiltable, with a large fixed stage that allows the observation of numerous samples. They have a single lens and a single focus system. Obviously, the German manufacturers immediately began to manufacture this type of microscopes, with special distinction being some such as E. Messter, P. Thate, H. Himmler and P. Waechter. The latter manufactured more than 20,000 trichinoscopes in the early years. Of all of them there are examples in the collection in the numbers: 20a, 51c, 51d, 51e, 51f, 51g and 51i.