Anaplasma Species in Africa—A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Abstract

Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

Anaplasma capra: a new emerging tick-borne zoonotic pathogen

“…Anaplasma bovis can cause fever, weight loss, incoordination, lymph node enlargement, and rarely death in ruminants (Chilton et al 2018 ). Anaplasma centrale is less pathogenic than A. marginale and usually causes subclinical infections in cattle, it is used as live vaccines against anaplasmosis caused by A. marginale in Israel, South Africa, South America, and Australia (Aubry and Geale 2011 ; Kolo 2023 ). While A. ovis generally causes mild clinical symptoms in sheep and goats, it can also cause acute infections with clinical symptoms such as hemolytic anemia, icterus, depression, anorexia, weight loss, and decreased milk yield in case the immune system of infected hosts is suppressed or in mixed infections with different pathogens (Dumler et al 2001 ; Renneker et al 2013 ).…”

Molecular Detection of Candidatus Anaplasma camelii in Naturally Infected Dromedary Camels (Camelus dromedarius) in Abu Dhabi Emirate, United Arab Emirates, 2019–2023

“…It is caused by Anaplasma spp., which belongs to the Anaplasmataceae family [ 4 ] that includes six genera, i.e., Ehrlichia, Anaplasma, Aegyptianella, Wolbachia, Neorickettsia, and Candidatus Neoehrlichia [ 5 ]. The disease occurs in tropical and subtropical regions of America, Europe, Africa, Asia, and Australia [ 6 , 7 , 8 ]. Anaplasmosis, also called Gall sickness or tick-borne fever, affects a wide range of hosts including cattle, sheep, goats, buffalo, and some wild ruminants [ 9 , 10 ].…”

Genetic diversity and prevalence of emerging Rickettsiales in Yunnan Province: a large-scale study

“…This order primarily includes Rickettsia , Anaplasma , Ehrlichia, Neoehrlichia , Wolbachia, and Orientia genera, each of which preferentially infects different vectorial invertebrate arthropods like ticks, fleas, mosquitoes, and mites [ 2 ]. Rickettsiales are highly prevalent and globally distributed across various arthropod vectors, animals, and human [ 3 , 4 ]. Tick-associated rickettsioses are recognized as significant emerging zoonoses worldwide.…”

“…Currently, there are at least 25 known tick species capable of transmitting pathogenic Rickettsia species [ 6 ]. Eight formally described species within the genus Anaplasma [ 7 , 8 ] and 4 species within the genus Ehrlichia that are extensively distributed among terrestrial wild animal hosts [ 4 , 9 , 10 ]. In China, at least 11 species of tick-associated Rickettsiales known to cause human disease have been confirmed [ 11 – 14 ].…”