Anaplasmosis is an infectious blood disease in cattle caused by the rickesttsial parasites Anaplasma marginale and Anaplasma centrale. It is also known as yellow-bag or yellow-fever. This parasite infects the red blood cells and causes severe anemia. It is most usually spread by ticks. Anaplasmosis is often found in countries with tropical climate. In Vietnam, the disease is common in dairy cows; the rate of infection with parasites is from 5% to 8%; The disease causes many damages to imported dairy herds.
2. CLINICAL SIGNS:
There are two species of rickettsial bacteria that cause anaplasmosis in cattle:
The parasite deforms red blood cells as well as reduces the life expectancy of red blood cells.
Bacterial toxins secrets into bloodstream, kill red cells, inhibits hematopoietic organs which cause severe anemia and chronic fatique syndrome.
The incubation time for the disease to develop varies from two weeks to over two months, but on averages six to twelve days.
Infected animal will suffer from severe anemia which causes high fever (40oC – 41,7oC), weight loss, breathlessness, uncoordinated movements. The disease will also cause jaundice, a skin condition.
Without proper treatment, infected animals will die from exhaustion within 7 – 10 days from acute infection and within 3 – 6 months from chronic infection.
The disease is generally mild in calves under a year of age, rarely fatal in cattle up to two years of age, sometimes fatal in animals up to three years of age, and often fatal in older cattle.
Imported dairy cows usually suffer from acute infection.
Imtermediate hosts can be divised into 2 groups:
Tetracycline is often used for clinical anaplasmosis. The most effective courses of treatment are doxycycline (a normal dose would be 100 mg every 12 hours for adults), rifampin and levofloxacin. After treatment most animals become resistant to the disease. Oxytetracycline and imidocarb have also been shown to be effective. Supportive therapy such as blood products and fluids may be necessary.
Before apply treatment, giving auxilliary medicine to animals is advisable such as:
In some regions around the world, vaccines are available to increase resistance to anaplasmosis. Typically, cases of anaplasmosis increase in late summer and fall as insect vectors increase. Therefore, control of vectors is key to preventing anaplasmosis.
Let’s remember that “Prevention is better than cure”. Once an animal got infected, it will usually remain a carrier of the disease for life. Carriers show no sign of the disease but act as sources of infection for other susceptible cattle.
It is strongly advisable to use SANFO VIATOX-SPRAY to eliminate intermidiate hosts in the barn.