Anaplasma marginale

A Microbial Biorealm page on the genus Anaplasma marginale

Anaplasma marginale in bovine erythrocytes - A Rickettsial agent transmitted by ticks. Photo credit: Veterinary Clinical Parasitology Images

Classification

Higher order taxa

Domain; Phylum; Class; Order; family [Others may be used. Use NCBI link to find]

Bacteria; Proteobacteria; Alphaproteobacteria; Rickettsiales; Anaplasmataceae; Anaplasma

Species

NCBI: Taxonomy

Genus species

Description and significance

Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Anaplasmosis is a form of tick fever carried by a specfic species of cattle tick. Anaplasmosis in cattle is caused by an organism called Anaplasma marginale that invades and multiplies in red blood cells. As the disease progresses, infected and even uninfected red blood cells are destroyed mainly in the liver and spleen, resulting in an increasing anaemia and even death in severe cases. Any stage of the cattle tick’s life cycle can become infected after feeding on an animal carrying Anaplasma organisms in its blood stream. The organism multiplies in the tick and will pass to later stages of the tick life cycle. However, it does not appear the infection is passed on to the eggs. Consequently, the next generation of ticks will not be infected unless they also feed on a carrier animal. Therefore an infected stage of the tick must transfer to a susceptible animal for transmission to occur. Because the adult male tick is more mobile and lives longer than other stages, it is the most likely stage to transmit the disease. Biting flies can transmit the disease but are less efficient vectors than ticks. Mechanical transmission via veterinary instruments (needles, dehorners etc.) is also possible and the organism can cross the placenta to the foetus. Calves from immune mothers receive temporary protection (maternal antibody) from the colostrum (first milk) which prevents anaplasmosis. This protection lasts about 3 months and, in most cases, is followed by an age resistance that lasts until the animals are about 9 to 12 months old. Calves exposed to anaplasmosis when the maternal or age resistance is high, rarely show clinical symptoms but develop a solid, long lasting immunity. It is therefore possible to have both Anaplasma marginale and cattle ticks present on a property without animal losses or clinical disease. If cattle are not exposed to Anaplasma as calves, the age resistance gradually wanes and these animals will become increasingly susceptible to the disease. If susceptible adult cattle are mixed with infected cattle in the presence of the cattle tick, serious losses due to anaplasmosis can occur. Clinical symptoms of infection include transient fever, weakness and respiratory distress particularly after exercise, depression and loss of appetite, jaundice, and brown urine due to bile pigments. Cattle that recover from anaplasmosis remain carriers of the organism and are immune to further disease.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

HealthGene - Molecular Diagnostic and Research Center. "D425 Anaplasma Marginale"

Anaplasma

[ Edited by Patricia Shih; student of Rachel Larsen and Kit Pogliano