An outbreak of bovine babesiosis in February, 2019, triggered by above average winter temperatures in southern England and co-infection with Babesia divergens and Anaplasma phagocytophilum

Abstract

Background Bovine babesiosis, commonly known as redwater fever, is a sporadic tick-borne disease in the United Kingdom. Outbreaks occur during the spring, summer and autumn months when ticks are active. This study reports the findings of an investigation of an outbreak of bovine babesiosis during the winter month of February, 2019. Methods DNA from blood, organ and tick samples taken from affected cattle were tested for the presence of piroplasm and Anaplasma phagocytophilum DNA using PCRs directed to the 18S rRNA gene and msp2 gene respectively. The species of piroplasm was confirmed by sequencing. Results Babesia divergens DNA was detected in the blood of five cattle displaying clinical signs of babesiosis within a herd of twenty. This parasite was also detected in three of ten ticks removed from one of the affected cattle. In addition, A. phagocytophilum was detected in three cattle tested and two of ten of the ticks. Conclusions An outbreak of bovine babesiosis during February is unusual as the tick vector, Ixodes ricinus, does not generally become active until temperatures rise later in the year. February of 2019 was unusual as average temperatures during the first week of the month reached over 10 °C, well above historical averages that are typically below 5 °C, and a temperature at which ticks can become active. This unusual weather event is likely to have triggered tick questing, that combined with a co-infection with two tick-borne pathogens caused the severe outbreak of disease.

Detection of Tick-Borne Pathogens in Red Deer (Cervus elaphus), United Kingdom

“…The primers and amplification conditions have been published previously [ 45 ]. A positive control DNA extracted from the blood of a cow infected with both pathogens was used throughout [ 46 ]. The size of the amplicons was confirmed by separation on a 1.5% agarose gel stained with Sybr ® Safe (Thermo Fisher Scientific, Horsham, UK) and visualized with UV illumination.…”

Ticks, Human Babesiosis and Climate Change

“…However, there is very little evidence for infections transmitted to cattle by such adventitious ticks, with only one suspected case in the far north of Norway occurring in the last 20 years [66]. A more definite climate effect on bovine babesiosis, though on a local scale, occurred recently in the south of England in February 2019, when temperatures exceeded the average for the time of year by more than 10 • C, causing very early tick activity and an outbreak of bovine babesiosis involving 20 cattle [68]. Babesia venatorum is also transmitted transovarially and is associated with roe deer, so presumably the distribution of this pathogen has been affected by the northward range expansion of its host [58].…”

Climate change related (re)emergingdiseases in cattle in the Netherlands : the possible use of natural (plant) substances in an integrated approach

“…Babesia divergens and A. phagocytophilum are transmitted by Ixodes ricinus and cause clinical disease in cattle. Co-infections of B. divergens and A. phagocytophilum in cattle have been described and can potentially enhance the severity of clinical disease (Johnson et al, 2020;Andersson et al, 2017).…”