Beef cattle - helminthic disease of cattle, buffalo and zebu caused by nematodes of the genus Thelazia, which parasitize in the conjunctival sac and under the third century lead to the development of conjunctivitis, keratitis, corneal ulceration and even loss of vision, is accompanied by a decrease in the productivity of a sick animal.
Etiology. The causative agents of telazioza are small nematodes from the suborder Spirurata of the family Thlaziidae and the genus Thlazia. In cattle parasitize Th. Rodesi, Th. Gulosa, Th Skrjabini, the first nematode in cattle is localized under the conjunctiva and the third eyelid, and the other two in the ducts of the lacrimal gland and in the lacrimal canal. In animals, the most common worms of the species Th. Rhodesi.
The surface of the body at Th. Rodesi is covered with coarse transverse striations, giving a jagged appearance to the parasite. The oral opening leads to a small oral capsule. Males are smaller than females and have a length of 11.4 mm, females 21 mm. The tail end of the male is bent, with a lot of preanal papillae and two uneven spicules (the length of the large spicule is 0.624 - 0.846 mm). In the female, the vulva is located in the anterior third of the body, behind the end of the esophagus. Larvae are from 0.2 to 0.49 mm long. The larvae have a spherical cap and a head end that is slanted without thickening.
Th. Gulosa does not have a coarse transverse striation of the cuticle, the larva has a spherical cap and the head end, which is slanted without bulges, has a wide oral capsule, with uneven spicules, the length of the greater spicule is 0.688-0.962 mm.
Th. Skrjabini also has no coarse transverse striation of the cuticles, its oral capsule is very small, the male has almost equal short spicules, their length is more than 0.186 mm.
In addition to cattle, telesias can parasitize horses, sheep, goats, dogs, and other animal species. The man can be sick with telaziozy.
Female parasite viviparous. After birth, the larvae stand out from the tear ducts of the host to the surface of the ocular conjunctiva. Further development of calves occurs with the participation of intermediate hosts - flies (Musca convexifrons, M. autumnalis and M. Larvipara). During the month, an invasive larva forms in the egg follicles of the flies. It penetrates into the fly's proboscis and when the insect comes into contact with the wet conjunctiva of the definitive host, it migrates to the conjunctival sac of the eye, and from there to the tear ducts. After 2-3 weeks, the helminth reaches puberty.
Epizootology. The source of the pathogen invasion is the definitive owners of the parasite - including cattle, which the owners drive out to pasture without prior de-worming. Depending on the geographical area, insect years begin in spring and summer at different times. In the Nonchernozem zone, insects appear in the first decade of June, in Central Asia and South Kazakhstan - in April, in the South Caucasus - in late April and early May. Pasture animals become infected 14-28 days after the appearance of the flies. Telazioz in invasive animals gradually increases, reaching its peak in July-September. Owners of private farms, peasant farms and agricultural enterprises should bear in mind that livestock of all ages is sick with calves. In some farms, all the livestock of animals is affected by the calves. Term parasitization of calves is limited to 10-11 months.
Pathogenesis. Telazii have a mechanical, toxic and inoculatory effect on the animal's body. Moving along the mucous membrane of the eye, parasites damage the cornea and conjunctiva, causing desquamation of the epithelium, swelling of the mucous membrane and proliferation of tissues, which is complicated by the pathogenic effect of banal microflora, causing exudative inflammation, leading to cornea opacification, up to its perforation.
Clinical signs. It is customary to distinguish three stages of the disease in a sick animal. A disease in an invasive animal begins with tearing, photophobia, and conjunctivitis. In the second stage, during a clinical examination of a sick animal, a veterinary specialist notes the appearance of sero-mucous or purulent secretions, and a conjunctival swelling appears. In the third stage of the disease, when examining the affected eye, we record clouding and ulceration of the cornea. In individual animals, it is necessary to register a protrusion and even perforation of the cornea. With the complication of keratitis by the secondary microflora, the animal's body temperature rises by 1-2 ° С. Telazia in an animal may result in loss of vision.
Pathological changes. In an animal patient with a telepathy, we note the presence of conjunctivitis, keratitis, clouding and ulceration of the cornea, and lens damage.
When conducting a histological study, we register in the cornea and conjunctiva changes in nerve fibers, expressed by argentophilia, varicose thickening, fragmentation and lysis of axial cylinders.
Diagnosis A veterinary specialist places a veterinary specialist on the basis of epizootological data, clinical signs of the disease and the results of larvoscopy of the tear fluid or swabs from the conjunctiva of the eyes when we find sexually mature calves and their larvae. According to the instructions, veterinary specialists of the farms in the summer conduct a monthly clinical examination for cattle telepathy.
Differential diagnosis. A veterinary specialist should differentiate between telaesiosis and infectious rhinotracheitis, rickettsial keratoconjunctivitis, non-infectious keratoconjunctivitis and hypovitaminosis A.
Treatment. Veterinary specialists use an aqueous solution of iodine with potassium iodide for the treatment of fever. To prepare the solution, take 1 g of crystalline iodine, 1.5 g of potassium iodide and 2 liters of water. First, in a small volume of filtered boiled water, a concentrated solution of potassium iodide is prepared and crystalline iodine is dissolved in it. Then add the required amount of water to the mixture. The solution is prepared on the day of use and stored in a dark container. For complete removal of the animal's eyelids, the patient's animal is washed three times with this solution using a rubber syringe with a rubber tip. For each washing, you need to spend 5-75 ml of solution.
In the treatment of fever, you can use a 3% solution of boric acid or remove the calves with a cotton swab moistened with a 3% solution of boric acid. With a cotton swab, the walls of the eye cavity and the area of the inner corner of the eye are wiped off.
The course of treatment consists of three washes following one after the other, repeated after 4-5 days. If the patient has pathological changes, symptomatic treatment is carried out.
In the case of the fever caused by Th. gulosa and Th. skrjabini treatment effectively subcutaneous use of a 25% aqueous solution of ditrazina-citrate at a dose of 0.016 g / kg twice with an interval of 24 hours or used by injection into the periorbital space once.
Loxuran 10% at a dose of 2.5 per 10kg body weight subcutaneously, twice after 24 hours.
For therapeutic and prophylactic purposes, Ivomek, Aversecta-2 (pharmacycin) subcutaneously in a dose of 1 ml of the drug per 50 kg of body weight once, fascoderma (clozantim) subcutaneously in a dose of 0.005 g / kg body weight (LW) once, levamisole subcutaneously in a dose of 0 , 0075 g / kg body weight (LW) once, fenbendazole (timbendazole orally once at a dose of 0.025 g / kg body weight (LW), tetramisole (timtetrazole) orally at a dose of 0.01 g / kg body weight (LW) once, albendazole inside once in a dose of 0.0075 g / kg (DV), store -0,0002 g / kg (DV) twice a day, the river RTIN 1% - 0.02 g / kg for two days in a row.
Retrobulbar blockade according to V.M. Aurorov - 0.5% solution of novocaine, which is injected from the bottom and above the eyeball of a 0.5% solution of novocaine 15-30ml. The blockade is done once every 5 days.
When a sick animal has purulent conjunctivitis, a furacilin 1: 5000 solution, novocaine-chlorotetracycline ointment (Novocain-5.0, chlortetracycline-5.0, Vaseline -90.0) are used in the treatment, in the presence of keratitis in a sick animal, Beta liniment is used. carotene 0.2%, eye drops prepared according to the following prescription acid 3.0, zinc sulfate-0.5, distilled water 100.0. With the development of corneal opacities, a freshly prepared potassium iodide ointment (potassium iodide-0.3, drinking soda-0.5, vaseline-10.0) is used.
Prevention. Prophylaxis of veal diseases consists in carrying out prophylactic deworming and extermination of pasture flies. In farms, planned preventive deworming of animals is carried out when animals are put on stall housing, as well as when pasturing livestock is pastured. For the extermination of flies used ectomin 0.1% concentration, 0.25% solution of neostomazan with an interval of 2-3 weeks, neocidol in 0.1% concentration. The first spraying is carried out by the owners of animals before transferring the animals to pasture, the subsequent spraying is carried out in 5-7 days or as needed, using various types of sprayers.
In livestock buildings to control flies, the use of a 1-2% ectominum, 0.5% neocidol emulsion at a rate of 50-100 ml / m² is recommended. Processing of livestock buildings from flies is carried out after the withdrawal of all animals from the premises. After the treatment, animals can be brought to the room no earlier than in 2 hours.
For spraying livestock against flies in agricultural enterprises, they use disinfection machines (LSD, WDM, etc.) and small-sized devices (automax, hydraulic remote controls, etc.) capable of creating a pressure of 3-4 atm. and providing fine and low-volume spraying of insecticidal liquids.
When working with insecticides, workers should strictly follow safety precautions.
Features of calf
Telazioz is one of the types of helminthiasis, and the role of its pathogens is played by nematodes called teliasis. Such nematodes can be localized in several places:
- conjunctival sac,
- third eyelid,
- ducts of the lacrimal glands.
As a result of the invasion, various eye lesions of animals of varying degrees of severity appear - starting with conjunctivitis and ending with swelling of the cornea of the eye.
Telazioz affects the organs of vision of cattle in the first place
The most favorable period for nematodes comes in summer, because it is at this time that they are able to capture a significant part of the population. During the warm season, infected individuals become peddlers of calves, which are rapidly introduced into new organisms and multiply rapidly. In some cases, these parasites manage to capture the entire herd as a whole.
Ways of infection
To understand how cattle infestation occurs in cattle, it is necessary to briefly delve into the life cycle of these parasites. Before the invasive larvae of roundworms get inside the animal, several stages must pass:
- It all starts with the fact that the female produces a certain number of larvae that are not originally invasive and do not pose a danger to animals
- Next, the larvae are absorbed by the flies of the cows, after which they begin their development inside these flies. In the process of short-term modifications (taking about a month), the larva becomes invasive and gains the ability to develop in the body of a potential carrier,
The larvae of calves move with the help of cow flies
Telasia who have reached sexual maturity live no more than a year, after which they die. Hypothetically, these nematodes retain their vital activity in the winter season, however, they cannot produce offspring, which explains the absence of outbreaks of telyasiosis in the cold season.
Causes of calves
Summarizing all the above, we can conclude that the following factors are involved in the infection of cattle:
- cows flies, the spread of which is very difficult to prevent, as animals come into contact with them when grazing on pastures,
- other already infected animals that are carriers of nematodes,
- lack of prevention or its ineffectiveness. Since it is almost impossible to control cow flies, all that a livestock breeder can do in a given situation is to carefully monitor the state of health of their animals and carry out periodic antiparasitic treatments of cattle.
In order for parasites to be not terrible for cattle, it must be periodically treated with anthelmintic agents.
The initial stage of the disease is rarely striking, so it may go unnoticed with inattentive examination of animals. The first stage of the development of fever is characterized by the following manifestations:
- increased tearing, the eyes of infected animals constantly shine,
- animals avoid any light, as it irritates the eyes even more,
- conjunctiva inflamed, acquiring an unhealthy reddish tint.
Teariness is a reaction of the eye to the invasion of the larvae.
The second stage of the fever is more obvious than the first. Many pastoralists recognize the disease at this stage, since it is accompanied by vivid symptoms:
- Inflamed conjunctiva swells and grows in size
- A whitish liquid begins to stand out from the animal's eyes - a combination of mucus and pus that seeps from the lacrimal canal.
The second stage of fever is sometimes easily confused with conjunctivitis.
It should be noted that medical intervention gives a guaranteed effect only if it occurred at the first two stages of the disease. Of course, a cure may occur when the disease passes to the final stage. However, the longer the nematodes spent in the organs of vision of the animal, the less likely a positive outcome of treatment.
From the third stage begins a series of irreversible changes in the body of cattle, which can lead to final blindness. Among the symptoms that indicate that the disease is already running are:
- corneal opacity. In addition to opacification, the cornea can also bulge or perforate unnaturally,
- general depressed state of the animal, fever.
In the third stage, many animals develop purulent conjunctivitis.
In addition to the symptoms associated with the state of the organs of vision, cows infected with calves decrease milk yield and the quality of milk becomes worse. If calves were infected with parasites, they begin to lag behind in the development of their relatives, gaining weight more slowly. It is believed that the younger the animal, the more difficult it is to endure parasitic invasions.
Methods of diagnosis depend on the stage of development of the disease. If we are talking about primary symptoms, then in order to make sure of his guesses, the veterinarian sends a tear fluid of the animal to the laboratory. The fact is that in some individuals, the first stage is almost asymptomatic and it is hardly possible to identify the disease based on an external examination of the animal.
Before a diagnosis is made, the veterinarian sends a sample of the discharge from the eye to the laboratory.
In the laboratory, under a microscope, specialists examine the tear fluid for the presence of mature nematodes, as well as their larvae. And if they are found, the veterinarian will prescribe the appropriate treatment.
If the veterinarian has found an animal whose disease has already developed enough to unequivocally establish the ailment, the need for laboratory research is eliminated.
Treatment of telazia
Treatment of telazioza is accompanied by the use of several groups of medicines, allowing a comprehensive effect on nematodes, destroying them and mitigating all the consequences of the active activity of parasites. In general, the treatment of invasion includes the following steps:
- eye instillation and rinsing with potassium iodide or boric acid,
- rubbing tetracycline ointment in the affected skin,
- subcutaneous administration of antiparasitic agents.
Most antiparasitic injections are done to the neck.
Immediately make a reservation that not all of these drugs will definitely need the animal. The treatment regimen is developed individually depending on how much damage the calf has managed to inflict on the body. If the disease has not gone beyond the first two stages, then herders often do without subcutaneous injections, limited to drops and antibacterial ointments.
Each type of treatment will be covered in the following chapters.
To speed up the destruction of calves and their removal from the eyes of an animal, veterinarians usually prescribe one of the following two drugs:
- potassium iodide. In order to prepare a solution of the desired consistency, you need to take one hundred milliliters of boiled water and dilute one gram of crystalline iodine in it, then add one and a half grams of potassium iodide to the resulting substance. Next, the concentrate is diluted with another two liters of water. The solution is buried in the pupils of the animals by means of syringes,
Potassium iodide is released in the form of tablets, powder and solutions
Различные варианты выпуска борной кислоты
Так же для промывания подойдут и другие капли, в составе которых имеются сульфат цинка и/или ортоборная кислота.
Терапия с применением антибиотиков назначается ветеринаром только в тех случаях, когда у животного начинаются различные осложнения, такие как гнойный конъюнктивит и инфицирование роговицы. As a treatment, antibacterial drugs of the penicillin group are most often prescribed, as well as sulfa drugs.
In order to cure diseases that appear on the background of telazioza, broad-spectrum antibiotics are used.
Important! Medicines that contain mercury chlorides are strictly contraindicated for use by animals infected with teliasia.
If the disease has not had time to cause complications of an infectious nature or serious corneal lesions, treatment of fever is carried out topically. As an ointment, veterinarians prefer to prescribe a tetracycline ointment (preferably having novocaine in its composition). If the cornea deteriorates, the animal may also be prescribed an ointment that contains potassium iodide.
Tetracycline ointment allows you to kill the bacteria on the skin around the eyes and remove inflammation
Details on how to use and dosage of specific drugs need to learn from a specialist.
As already mentioned, antihelminthic and antiparasitic medications usually imply a subcutaneous route of administration. But there are also powders or liquids that are intended for oral use. The most well-known and proven drugs are described in the table below.
Table 1. Antiparasitic drugs for fever
Roundworms of calves (small nematodes) cause telaziosis in cows. Like other parasites, they are divided into several dangerous species that are the main causative agents of the disease:
- Thelazia rhodesi - considered the most pathogenic form. Sizes: the length of the male is 10 mm, the width is 0.45 mm, the female can reach 21 mm in length and 0.50 in width. Body color varies from yellow to brown, the cuticle is transversely striated and slightly serrated. The larvae are 0.49 mm long, have a spherical cap and beveled head end without bulges.
- Thelazia gulosa - the parasite is equipped with a large oral capsule resembling a bowl. The size of the male is 9.1 mm long, 0.53 mm wide. The female is 16 mm in length, 0.60 mm in width.
- Thelazia skrjabini - differs from other species by a small oral capsule and short spicules. The transverse striation of the cuticle is completely absent. The length of the male is 9 mm, the females 19 mm.
Helminth development cycle
Infection with teliasis occurs after the attack of the infested flies on the moist skin of the inner corner of the eye or eyelid of the cow. Invasive larvae of teliasias fly through the proboscis of the fly initially on the skin, then on the eyes, where they develop to maturity. The process takes about 3-6 weeks. The life span of nematodes is a year. In the cow's eyes, they calmly survive the winter period.Detailed development scheme for calves:
Sources of infection
Infection of livestock occurs in various pastures, in rare cases - in barns. The flight of cow flies begins as early as May and lasts until the autumn, just in the warm season of cow walking.
An infected cow has 3 stages of painful development, which manifest themselves through certain clinical symptoms:
- Stage 1 - acute conjunctivitis is manifested, minor injuries can be noted on the cornea, the animal avoids light in every possible way, its eyes are very watery,
- Stage 2 - after a few days pus (serous mucous fluid) starts to stand out from the affected eyes, along with mucus, there is a strong redness and swelling on the eyelids, sometimes the cow is not able to even open the eyes
- Stage 3 - sores appear on the cornea; 1–2 ° С.
- the presence of conjunctivitis, keratitis,
- damage to the lens
- clouding of the cornea, the appearance of ulcers on it.
Anthelmintic and antiparasitic drugs
For the complete eradication of the disease and the prevention of the development of helminths in the rest of the population, antiparasitic therapy is carried out to the entire population. Effective drugs and dosage:
- Ivomek - injected once, 1 ml of medicine per 50 kg of individual,
- Levamisole - once, 0,0075 g per 1 kg,
- Rivertin - 2 days, 0.2 g per 1 kg,
- Fascoverm - once, 0,005 g per 1 kg,
- The solution ditrazina-citrate (25%) is injected subcutaneously, twice with an interval after 24 hours. Dosage - 0,016 g per 1 kg of mass.
An important role in the speedy recovery is played by additional washings with special solutions and drops:
- A solution of iodine with potassium iodide. Method of preparation: Dilute 1 g of crystalline iodine and 1.5 g of potassium iodide in two liters of purified water. Washing the affected eye is done three times a day with a rubber tip syringe. The flow rate for each wash is about 75 ml.
- Boric acid solution (3%). The walls of the eye cavity and the area of the inner corner of the eye are wiped with moistened cotton swabs. Manipulation is repeated 3 times a day, for 5–7 days.
- Antibacterial Penicillin Drops on 50 thousand units, are applied according to the recipe of the veterinarian.
- Novocaino-penicillin ointment used in the presence of ulcers on the eye cornea. Before use, the agent must be kept for 5–7 days at a temperature of + 2–4 ° С.
- Chamomile, calendula, marsh wild rosemary infusions (in the ratio 1: 100).
Prevention of cow calves
In warm regions, where outbreaks of telaesiosis occur annually (Bashkortostan, Ukraine, southern Russia), at the end of the stall period and spring, farmers produce planned anthelmintic treatment of the entire herd. For prevention, as a rule, a water-iodine solution is used.
Another measure is the extermination of pasture flies (spreaders of infection). To do this, apply 0.1% ectomine, which is sprayed on animals before going out to pasture. A few more important recommendations:
- the hay that feeds the cows should be as clean as possible from the dung,
- periodic pasture change will reduce the risk of helminthization,
- calves should be grazed separately from adults,
- Do not graze cows nearby with sheep, the latter are most often infected with tapeworms,
- avoid situations in which the cow will drink from a swamp or puddle,
- it is necessary to keep livestock only in clean barns.
The diagnosis of veal disease can be made by a veterinarian on the basis of the studied clinical manifestations of the disease. If the symptoms are mild, which is characteristic of the first stage of helminthiasis, laboratory testing of tears or conjunctival swabs may be required. Detection of mature specimens of calves and their larvae in the eye is the basis for diagnosis.
Development biology of calves
Treatment of telazia is aimed at eliminating the causative agent of the disease, as well as at eliminating complications. Apply eye rinsing to combat calves. For this, the following solutions are used:
To prepare the iodide solution, take a small amount of clean boiled water (100 ml). It is diluted with 1 gram of crystalline iodine, to the resulting liquid, add 1.5 grams of potassium iodide. The resulting concentrate is diluted with water so that the total volume of the solution is 2 liters. With this tool, the eyes of an animal are washed several times with the help of a usual syringe.
The solution of boric acid is prepared as follows - 3 ml of concentrate is added per 100 ml. The corners of the eyes, eyelids and conjunctiva are washed with a syringe agent or a sterile bandage or cotton swab. It is usually enough three procedures with an interval of 4 days to remove the larvae of calves.
Antibacterial therapy is carried out in the case of the development of complications - purulent conjunctivitis and corneal infection. Penicillin antibiotics or sulfa drugs are used for treatment. Preparations with mercuric chlorides are contraindicated in fever.
The nematode treatment regimen includes the use of anthelmintic and antiparasitic drugs. They are injected subcutaneously:
Antiparasitic injections are also used to prevent the development of helminthiasis. The scheme of treatment and dosage prescribed by a veterinarian.
Reference. After the injection, it is allowed to consume the milk of cows or goats no earlier than in 2 weeks. The animal is sent for slaughter 28-30 days after the use of antiparasitic agents.