Texas fever
Texas fever (syn. Cattle babesiosis ) is an infectious disease of ruminants caused by the single cell Babesia bigemina and (as Theobald Smith recognized) transmitted by ticks . It occurs in the tropical and subtropical regions of all continents. Affected animals show fever, diarrhea and blood urine, some of which are fatal. Tick-killing agents are used for prophylaxis.
Pathogen and transmission
B. bigemina is transmitted by ticks of the genus Rhipicephalus . In Asia, Australia and South America the disease is transmitted by Rhipicephalus microplus , in Central America also by Rhipicephalus annulatus . This type of tick also occurs in southern Europe through imported animals. In Africa, the disease is also transmitted by Rhipicephalus decoloratus . The infection occurs through the sporozoite-containing saliva of young ticks. If it at around six-legged larva is, they have never sucked blood and Babesia noticed by her mother. The parasite infiltrates (penetrates) the erythrocytes and divides in them. It then destroys the host cell and infects new red blood cells during lysis .
distribution
B. bigemina is common in the tropical and subtropical regions of all continents. In Central Europe, too, it occurs particularly in the months of May, June and September. In Australia, the disease is of less economic importance. In South Africa, however, Babesia bigemina is predominant, due to the further spread of the tick transmitted by Babesia bigemina .
The disease caused heavy economic losses in the USA at the end of the 19th century. Due to a large-scale extermination of the Rhipicephalus ticks, North America (Texas) is now considered to be free from beef babesiosis.
Symptoms and course of the disease
The incubation period of Texas fever varies between 8 days in older animals and up to 30 days in younger animals. Typical clinical symptoms here are a severe impairment of the general condition, initially headache, loss of appetite, diarrhea, increased pulse rate and limb back pain. A specific symptom is the red to black-brown color of the urine due to hemoglobinuria .
The disease initially manifests itself as persistent fever (40 to 41.8 ° C, normal temperature in cattle: 38 ° C) and gastrointestinal disorders (diarrhea). In the later course of the disease, the animal loses more and more strength and falls into a coma . Death from brain or kidney failure occurs within hours.
Adult and older cattle are more severely affected and have a higher mortality rate than calves.
It's like a childhood disease for calves . You will then achieve lifelong immunity on the basis of a premunity .
diagnosis
A blood smear is colored using the Giemsa method so that the parasites can be seen in the erythrocytes. A clear result can be seen after about 7 to 10 days. The detection of blood in the urine (with test sticks) and signs of tick bites serve as further indications of a possible infection . The detection of fatal infections is determined by serological methods ( ELISA , indirect immunofluorescence antibody test , immunohistochemistry ).
therapy
Effective preparations are, for example, Berenil and Imizol .
prophylaxis
To combat ticks, the herds are periodically driven through immersion baths with tick- killing solutions.
literature
- Heinz Mehlhorn, Dieter Düwel, Wolfgang Raether: Diagnosis and therapy of the parasites of pets, farm animals and pets. Gustav Fischer Verlag, Stuttgart, New York 1996, ISBN 3-437-30493-3 .
- Vogl, Sigrid: Molecular-phylogenetic differentiation of babesia of cattle. Dissertation, LMU Munich: Veterinary Faculty, 2004, urn : nbn: de: bvb: 19-18107
- Paul de Kruif : Theobald Smith . Ticks and Texas fever. In: Paul de Kruif: Microbe hunters. (Original edition: Microbe Hunters. Harcourt, Brace & Co., New York 1926) Orell Füssli Verlag, Zurich / Leipzig 1927; 8th edition ibid 1940, pp. 224–241.
Individual evidence
- ^ O. Wilford Olsen: Animal Parasites . 3. Edition. University Park Press, 1974, pp. 155 ff .
