A Review of Bovine Anaplasmosis

Abstract

Bovine anaplasmosis, caused by Anaplasma marginale, is an infectious but non-contagious disease. It is spread through tick bites or by the mechanical transfer of fresh blood from infected to susceptible cattle from biting flies or by blood-contaminated fomites including needles, ear tagging, dehorning and castration equipment. Transplacental transmission of A. marginale may contribute to the epidemiology of bovine anaplasmosis in some regions. Bovine anaplasmosis occurs in tropical and subtropical regions worldwide. Cattle of all ages are susceptible to infection with A. marginale, but the severity of disease increases with age. Once cattle of any age become infected with A. marginale, they remain persistently infected carriers for life. Diagnosis of bovine anaplasmosis can be made by demonstration of A. marginale on stained blood smears from clinically infected animals during the acute phase of the disease, but it is not reliable for detecting infection in pre-symptomatic or carrier animals. In these instances, the infection is generally diagnosed by serologic demonstration of antibodies with confirmation by molecular detection methods. The susceptibility of wild ruminants to infection by A. marginale and the role of wild ruminants in the epidemiology of bovine anaplasmosis are incompletely known owing to lack of published research, lack of validation of diagnostic tests for these species and cross-reaction of Anaplasma spp. antibodies in serologic tests. Control measures for bovine anaplasmosis vary with geographical location and include maintenance of Anaplasma-free herds, vector control, administration of antibiotics and vaccination.

Co-infection with bovine viral diarrhoea virus and Anaplasma marginale in a dairy cattle herd may lead to acute bovine anaplasmosis

“…After identification of Anaplasma marginale, the results of the serological tests also support the conclusion that the pathogen had been endemically present in the herd also before the current outbreak. The results of the serological tests are consistent with the data reported in the literature (Baumgartner et al 1993;Birdane et al 2006;Aubry and Geale 2011), as the seropositivity rate was substantially higher (50%) in the older animals (3-to 4-year-old, more than 4-year-old) than in the younger age groups (10-30%). Despite the fact that clinically apparent anaplasmosis occurred in the older animals, the younger (3-to 12-month-old) age groups also contained seropositive animals which, however, did not exhibit clinical signs.…”

“…Acute outbreaks are primarily triggered by stress factors or immunosuppressive effects in susceptible animals (Kocan et al 2010). Currently the vertical transmission of the pathogen is not fully clear yet; however, in certain regions the transplacental transmission of A. marginale has a profound impact on the epidemiological status of the pathogen (Aubry and Geale 2011). Calves usually do not show clinical signs after an intrauterine infection; however, there has been a report that in four calves that acquired transplacental infection during their intrauterine life the disease subsequently manifested itself in severe clinical signs after birth leading to fatal outcomes (Pypers et al 2011).…”

Potential economic impact assessment for cattle parasites in Mexico. Review

“…Therefore, the total economic loss attributable to R. microplus in the Mexican cattle herd could approach US$ 573'608,076 (Table 3). R. microplus is the vector of the hemoprotozoans Babesia bovis and B. bigemina, which cause bovine babesiosis, and the intraerythrocitic rickettsia Anaplasma marginale that causes anaplasmosis (57,58) . Babesiosis and anaplasmosis are responsible for important economic losses in the cattle industry of tropical and subtropical areas of the world.…”

Outbreak of anaplasmosis associated with the presence of different Anaplasma marginale strains in dairy cattle in the states of São Paulo and Goiás, Brazil

“…The major surface proteins (MSPs) MSP5, MSP4 and MSP1a have been widely used for molecular characterization of A. marginale (AUBRY & GEALE, 2011). MSP1 is an adhesin important to bovine erythrocytes and tick cells.…”

“…This rickettsia is a gram negative, obligate intracellular bacterium that can be biologically transmitted by ticks, can be mechanically transmitted by bloodsucking flies and fomites contaminated with infected blood, and, less commonly, can be transmitted via the placenta (KOCAN et al, 2010;AUBRY & GEALE, 2011).…”