Cattle pyroplasmosis ( babesiosis ) , or Texas fever , or chihir, is a vector-borne disease of animals caused by blood red blood cell parasites - pyroplasmas ( babesias ). The life cycle of pyroplasm occurs in the organisms of two hosts - cattle and tick- carriers. Propagation of pyroplasmas in animals occurs in the blood by simple division, and in the body of ticks - in tissues, hemolymph and eggs. In animals, they multiply first in the internal organs, and then in the peripheral blood.
In Russia, pyroplasmosis of cattle is distributed mainly in the southern part, but it also occurs in the central regions, and proceeds benignly in comparison with warmer regions. Outbreaks are noted in spring, summer and sometimes in autumn.
In the United States, Texas fever was almost eliminated along with the carrier, the tick , although there are still small outbreaks associated with the importation of infection from Mexico [1] .
Content
- 1 History
- 2 Clinical picture
- 3 Treatment
- 4 Prevention and control measures
- 5 notes
- 6 Literature
History
At the end of the 19th century, an epidemic of an unknown disease broke out among animals on the northern US ranch, destroying almost the original herds (the annual loss due to cattle death was $ 130.5 million) [1] . The disease was called Texas fever , as cattle breeders noticed that the cattle brought in from the south of the USA brought the infection. Cattle breeders also noticed that cattle brought from the south in winter did not bring ticks or infections, while in the summer, when there are many ticks on animals, an epidemic breaks out among northern animals.
The US Department of Agriculture released a good grant [2] , and Dr. Theobald Smith and his employee Kilborn enthusiastically embarked on research [1] . Researchers found tiny pear-shaped organisms in the red blood balls of diseased cows. It was also found that, despite the fact that Boophilus ticks parasitizing on cows spend their whole lives on one animal - they transmit the infection to the next generation, and young ticks that hatched from their testicles also infect cows [1] [2] .
It was also possible to establish why southern cattle remain healthy, but infect northern cattle. Sick animals develop non-sterile immunity , which remains until at least single blood parasites remain in the blood, which are enough to infect ticks, and through them non-immune cattle [1] [2] .
After Smith and Kilborn published their results in 1893, a merciless war broke out in the USA with the tick tick Boophilus annulatus, which ended in 1960 with its complete extermination [1] .
Clinical picture
With a spontaneous lesion of pyroplasmosis, the incubation period lasts from 6 to 30 days. The disease proceeds most often sharply, less often chronically. Within 1 day, body temperature rises to 42 ° C, animals are sharply inhibited. The mucous membranes at the beginning of the disease are anemic, and on the 3-4th day of the disease icteric. Animals more often lie, stop eating and water, outflows appear from the eyes. Intestinal motility is weakened. In the first period of the disease, the urine becomes yellowish, then acquires a reddish color, and on the 3-4th day of the disease it becomes dark brown. Pulse and breathing become more frequent, cachexia occurs. With an unfavorable prognosis and untimely treatment, a fatal outcome occurs within 6-7 days from the onset of the disease.
Chronic course is usually observed in animals with increased resistance or in previously ill animals. Relapses of the disease are sometimes possible, which are manifested by a repeated increase in body temperature, depression, cachexia, edema.
The diagnosis is made on the basis of clinical and laboratory blood tests, taking into account epizootological data, the presence of ticks - carriers of the disease, the season of spread of the disease.
It should be borne in mind that with pyroplasmosis the process can develop very rapidly and quickly, ending in the death of the animal on the 2-3rd day. This indicates enhanced reproduction of pyroplasmas and their defeat of a large number of red blood cells. Sometimes parasites can be detected in patients already at the end of the incubation period, and on the 1-2 day of the disease their number increases dramatically. Often body temperature does not reach 40 degrees Celsius. The next day they find "bloody urine." [3]
Treatment
For the treatment of pyroplasmosis, you can use berenyl (azidine) in the form of a 7% aqueous solution intramuscularly or subcutaneously at a dose of 3.5 mg / kg of body weight once. In severe cases, the injection is repeated. Diamedin is also prescribed in a dose of 1-2 mg / kg of body weight intramuscularly in the form of a 10% aqueous solution. Animals provide peace, diet food. Since a deficiency of vitamin B12 (cyancobalamin) is created in the animal’s body with this disease, it is necessary to introduce vitamin B12, as well as heart preparations, such as sulfocamphocaine, into feed or injections. In severe cases, hemodesis is administered intravenously or subcutaneously.
Prevention and control measures
The main task in eliminating and preventing the development of pyroplasmosis is to carry out a complex of preventive measures, including chemoprophylaxis and the fight against vector ticks. To do this, animals are periodically treated with repellents and berenyl (azidine) is injected every 10 days .. Since the ticks are the weakest link in the epizootic chain of babesiosis, then preventive measures should be aimed primarily at combating them. Cattle are grazed on pastures where there are no ixodid ticks. Reliable prevention of the disease is the stall keeping of animals and their regular bathing or spraying with emulsions of acaricidal preparations (permethrin, K-otrin, butox, benzophosphate, etc.), which are repeated every 9 to 10 days. A set of organizational, economic and agrotechnical measures is carried out in order to create conditions unfavorable for the development of ticks: reclamation work, organization of cultural pastures. Chemoprophylaxis of babesiosis is also carried out. In an area unsuccessful with respect to this invasion, at the beginning of the outbreak of babesiosis, animals are injected with berenyl or azidine, which prevents infection with blood parasites for 2-3 weeks.
Notes
- ↑ 1 2 3 4 5 6 Daniel M. - Secret Paths of the Death Carriers. - Progress, 1990. ISBN 5-01-002041-6
- ↑ 1 2 3 Paul de Kreif (de Cruy) . Microbial hunters. Publisher: Astrel, Polygraphizdat, 2012. ISBN 978-5-271-35518-9 , ISBN 978-5-4215-3274-3
- ↑ V.S. Ershov et al. Parasitology and invasive diseases of farm animals. - M. , 1959. - 492 p.
Literature
- Dorosh M. , “Cattle Diseases”, isbn 5-9533-1681-x, Veche, 2007.