Nosematosis of bees - signs, treatment, prevention

Bee nosematosis is a serious invasive disease of adult bee colonies, affecting their digestive system. It is caused by a single-celled spore-forming parasite nosema, which penetrates the body of the insect and is localized in the epithelial cells of the midgut.

Affected intestines of bees cease to fully perform their functions, develops severe diarrhea, which is the most typical external sign of this disease.

Nosematosis develops according to this scheme. Spores of the pathogen enter the digestive tract of insects and settle in the midgut. Here they germinate and the embryo penetrates into the cells of the surface layer, where they continue their development.

Across 3 days this process ends with the destruction of cells and the release into the intestinal lumen of new protozoa. Gradually the epithelium is rejected, nutrients can enter the body. Bees are weakening, lose appetite, which later ends in their death.

How the disease manifests itself

Nosematosis can occur in overt or covert form, which can pass into one another. Acute occurs in regions with long winters and develops in bee colonies before spring, at that moment, when wintering is not over and the exhibition of hives is still far away. Sometimes the first stage of the disease coincides with the beginning of egg laying in the uterus and peaks in a couple of months, during the height of breeding brood.

Acute nosematosis is characterized by the following symptoms:

• The bee family is quite excited, emits continuous noise.
• Some bees fly out of the hive, but they can't fly far, they soon perish.
• If the wintering of insects takes place indoors, it has a characteristic unpleasant odor.
• Traces of defecation are visible on the eyes, and if you open the lid of the hive and look inside, it will turn out, that the frames near the club are also very polluted with bee droppings.
• In the spring the cleaning flight is sluggish, individual specimens cannot take off and crawl near their home. They are weakened, the abdomen of the increased sizes can be observed, obliquely placed in relation to the body of the wing.
• Mass death of bees can be noted, especially in late winter - early spring. Live insects are mostly significantly weakened, respond poorly to external stimuli.
• There is a so-called "wet submarine" (if you click on the belly of a dead bee, then a large amount of liquid feces will be released).
• Insects consume a lot of protein food, which further intensifies the defeat.
• The total number of workers is declining, they bring less bribes. The final productivity of the bee colony suffers from this, the amount of honey collected decreases.
• Feeding bees stop caring for their offspring.
• The number of bee-collectors is decreasing and young insects are moving faster, corresponding to their age, starting to fly for a bribe.
• The infected uterus stops laying eggs and dies. There is an unplanned change.
• Drones become incapable of performing their functions.

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Nosematosis in a latent form is more characteristic of the south, with warm winter areas and occurs in spring and summer. It differs in that, that all the symptoms of this disease are smoothed out and are observed only in some individuals.

Yet, It does not mean, that all is well. Over time, nosematosis progresses, finds new victims, the number of healthy insects is declining. The new brood is poorly developed, there is a quiet replacement of the uterus.

This is what beehive frames look like in nosematosis in bees.

How sharp, and the latent type of disease is difficult to diagnose only on the basis of external signs, as the most characteristic symptom of this disease is diarrhea, may be inherent in other diseases of bees or be the result of bees eating poor quality food.

Much more accurate to determine, what to deal with, it is possible by means of laboratory researches of fabrics and contents of intestines of the affected copies. In addition to microscopic analysis, there is another reliable way to recognize the disease - the appearance of the midgut of dead bees. In healthy insects, the midgut is reddish-brown and has a folded surface, and in those infected with nosematosis - white and smooth surface. The gut itself sank, increased in length and inflated, easily torn.

How the disease occurs

Spores of nozema in nature are found everywhere - in water, soil, on plants and quite resistant to chemical and physical influences. Therefore, they can be the primary source of disease for the entire bee family:

• Be weakened insect, in the body of which spores can enter with poor quality food or water.
• Patients with nosematosis thieves, who come into contact with healthy insects in someone else's hive.
• The disease is also transmitted from sick families to healthy ones through common food, in which the infection is present.
• Undisinfected empty honey frames, which were previously located in the infected hive.
• Frames with affected brood, which strengthen weak families.
• Properly unprocessed inventory, by means of which necessary works on collecting honey and care of bees are carried out.

The development of nosematosis is preceded by:

• increase in outside air temperature or its sharp fluctuations;
• late spring;
• long windy and rainy weather;
• high humidity inside the hives;
• early brood yield;
• untimely autumn feeding of bee families with sugar, conducted to form a family goes to winter;
• poor quality feed or lack thereof;
• a large number of pads in winter food;
• carbohydrate starvation of bees.

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Any of these factors can significantly contribute to the weakening of the bee colony and the development of the disease, and a combination of several of them increases the risk of nosematosis outbreak several times.