Molecular detection of Anaplasma marginale in stable flies Stomoxys calcitrans (Diptera: Muscidae) feeding on a tick-free bovine herd

Abstract

Data on the implication of the stable fly (Stomoxys calcitrans, Diptera: Muscidae), in the transmission of Anaplasma marginale in tick-free cattle is scarce. Hence, the objective of this investigation was to detect the presence of DNA from A. marginale in stable flies caught near a bovine herd, which has been maintained free of ticks for 40 years, and occasionally presents some clinical cases of anaplasmosis. Twenty-four batches of S. calcitrans (15 flies each) were collected in the morning and in the afternoon twice a week (except for one catch in one week of September and one catch in one week of December) during 12 catching days in a period of four months. Their DNA was obtained and analysed by nested PCR (nPCR) to identify the presence of A. marginale DNA. Seven of the batches (29.16 %) were positive for A. marginale, as detected by an nPCR that targets the A. marginale msp5 gene. Similarly, in two out of 12 catching days (16.66 %), those S. calcitrans batches collected in the morning and in the afternoon, were positive for A. marginale, while those S. calcitrans groups collected in three out of 12 catching days (25 %), were positive for the rickettsia. The obtained results suggest that A. marginale transmission is carried out mechanically by S. calcitrans, favouring the circulation and maintenance of the microorganism in this particular bovine herd.

Molecular of Anaplasma marginale Theiler (Rickettsiales: Anaplasmataceae) in horseflies (Diptera: Tabanidae) in Uruguay

“…However, in tick-free areas of Argentina, anaplasmosis outbreaks occur for unknown reasons at 4-to 7-year intervals 18 . In tick-free areas, the occurrence of anaplasmosis outbreaks on farms where there were no previously infected animals or contaminated fomites draws attention to haematophagous dipterans, such as horseflies and stable flies, as potential mechanical vectors 7,19 . From this perspective, our results point to P. lindneri and D. missionum as potential vectors of this pathogen.…”

Fly Borne Diseases in Animals

“…This genus is believed to have originated in Africa, where the largest number of species is currently found (Scholl et al 2003). The stable fly, S. calcitrans mechanically transports Anaplasma marginale to cattle, which causes Anaplasmosis, an economically important livestock disease (Bautista-Garfias et al 2018).…”

“…The haematophagous horn fly Haematobia irritans (Figs. 8 and 9) has also been implicated in the mechanical transmission of the rickettsia Anaplasma marginale to cattle in Mexico (Rodríguez et al 2009) and in some areas of the world where there are no ticks (biological vectors) (Bautista-Garfias et al 2018). Another important group of hematophagous insects is members of the genus Tabanus, which transmit a wide variety of pathogenic organisms to the domestic animals (Baldacchino et al 2014).…”