The natural history of Anaplasma phagocytophilum.
Abstract: Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocytic agents causing similar diseases in dogs in the USA in 1971 and 1982. Until the discovery of human granulocytic anaplasmosis (HGA) in the USA in 1994, these organisms were thought to be distinct species of bacteria infecting specific domestic animals and free-living reservoirs. It is now widely accepted that the agents affecting different animal hosts are variants of the same Gram-negative obligatory intracellular bacterium, which is transmitted by hard ticks belonging to the Ixodes persulcatus complex. One of its fascinating features is that it infects and actively grows in neutrophils by employing an array of mechanisms to subvert their bactericidal activity. It is also able to survive within an apparently immune host by employing a complex mechanism of antigenic variation. Ruminants with TBF and humans with HGA develop severe febrile reaction, bacteraemia and leukopenia due to neutropenia, lymphocytopenia and thrombocytopenia within a week of exposure to a tick bite. Because of the severe haematological disorders lasting for several days and other adverse effects on the host's immune functions, infected animals and humans are more susceptible to other infections.
Publication Date: 2009-09-20 PubMed ID: 19811878DOI: 10.1016/j.vetpar.2009.09.013Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Diagnosis
- Disease
- Disease control
- Disease Diagnosis
- Disease Etiology
- Disease Management
- Disease Outbreaks
- Disease Prevalence
- Disease Surveillance
- Disease Transmission
- Disease Treatment
- Equine Health
- Immunology
- Infection
- Pathogens
- Public Health
- Tick-Borne Diseases
- Vector-borne disease
- Veterinary Medicine
- Zoonotic Diseases
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research article provides comprehensive information about Anaplasma phagocytophilum, a bacterium transmitted by ticks that can cause severe febrile reactions, haematological disorders, and increased susceptibility to other infections in humans and animals.
Overview of Anaplasma phagocytophilum
- Anaplasma phagocytophilum is a type of bacteria that infects specific domestic animals and free-living reservoirs.
- It was formerly known as Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis. The new name was given after the reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales.
- It is transmitted by hard ticks belonging to the Ixodes persulcatus complex.
Diseases Caused by Anaplasma phagocytophilum
- A disease caused by this bacterium, known as Tick-borne fever (TBF), was first described in 1932 in Scotland.
- A similar disease was described in horses in the USA in 1969, followed by two separate granulocytic agents causing diseases in dogs in 1971 and 1982 in the USA.
- Human Granulocytic Anaplasmosis (HGA) was first discovered in 1994 in the USA.
Notable Features and Effects of Anaplasma phagocytophilum
- This Gram-negative, obligatory intracellular bacterium infects and grows actively in neutrophils, using various mechanisms to subvert their bactericidal activity.
- The bacterium is capable of surviving within an immune host by employing a complex mechanism of antigenic variation.
- Infected ruminants and humans develop severe febrile reactions, bacteraemia, and leukopenia due to neutropenia, lymphocytopenia, and thrombocytopenia within a week of a tick bite.
- Severe haematological disorders and other adverse effects on the host’s immune functions can occur and can last for several days, making infected animals and humans more susceptible to other infections.
Cite This Article
APA
Woldehiwet Z.
(2009).
The natural history of Anaplasma phagocytophilum.
Vet Parasitol, 167(2-4), 108-122.
https://doi.org/10.1016/j.vetpar.2009.09.013 Publication
Researcher Affiliations
- University of Liverpool, Department of Veterinary Pathology, Veterinary Teaching Hospital, Leahurst, Neston, South Wirral CH64 7TE, UK. zerai@liverpool.ac.uk
MeSH Terms
- Anaplasma phagocytophilum / physiology
- Animals
- Disease Outbreaks
- Disease Reservoirs
- Ehrlichiosis / epidemiology
- Ehrlichiosis / immunology
- Ehrlichiosis / microbiology
- Humans
- Rodentia
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
