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.

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.

Hyalomma rufipes on an untraveled horse: Is this the first evidence of Hyalomma nymphs successfully moulting in the United Kingdom?

During September 2018, a tick was submitted to Public Health England's Tick Surveillance Scheme for identification. The tick was sent from a veterinarian who removed it from a horse in Dorset, England, with no history of overseas travel. The tick was identified as a male Hyalomma rufipes using morphological and molecular methods and then tested for a range of tick-borne pathogens including; Alkhurma virus, Anaplasma, Babesia, Bhanja virus, Crimean-Congo Haemorrhagic fever virus, Rickettsia and Theileria. The tick tested positive for Rickettsia aeschlimannii, a spotted fever group rickettsia linked to a number of human cases in Africa and Europe. This is the first time H. rufipes has been reported in the United Kingdom (UK), and the lack of travel by the horse (or any in-contact horses) suggests that this could also be the first evidence of successful moulting of a Hyalomma nymph in the UK. It is postulated that the tick was imported into the UK on a migratory bird as an engorged nymph which was able to complete its moult to the adult stage and find a host. This highlights that passive tick surveillance remains an important method for the detection of unusual species that may present a threat to public health in the UK. Horses are important hosts of Hyalomma sp. adults in their native range, therefore, further surveillance studies should be conducted to check horses for ticks in the months following spring bird migration; when imported nymphs may have had time to drop off their avian host and moult to adults. The potential human and animal health risks of such events occurring more regularly are discussed.