AUTHOR=Grandi Giulio , Aspán Anna , Pihl Jenny , Gustafsson Katarina , Engström Fredrik , Jinnerot Tomas , Söderlund Robert , Chirico Jan 

TITLE=Detection of Tick-Borne Pathogens in Lambs Undergoing Prophylactic Treatment Against Ticks on Two Swedish Farms

JOURNAL=Frontiers in Veterinary Science

VOLUME=5

YEAR=2018

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2018.00072

DOI=10.3389/fvets.2018.00072

ISSN=2297-1769

ABSTRACT=<p>Tick-borne pathogens (TBPs), especially <italic>Anaplasma phagocytophilum</italic>, cause disease in grazing livestock. Tick prophylaxis is, therefore, a routine practice in sheep flocks in Sweden, especially in central, southern, and coastal areas of the country where ixodid ticks (<italic>Ixodes ricinus</italic> and <italic>Haemaphysalis punctata</italic>) are present. In the present study, the status of infection by <italic>A. phagocytophilum</italic> and other TBPs in lambs treated with tick prophylaxis has been assessed serologically and with polymerase chain reaction (PCR). Blood samples (<italic>n</italic> = 78) from lambs (<italic>n</italic> = 20) subjected to regular tick prophylactic treatment (flumethrin, Bayticol<sup>®</sup>) at two sites in different regions in Sweden (Östergötland, Gotland) were collected on four occasions from May until July 2013. The severity of clinical signs in <italic>Anaplasma-</italic>infected animals is known to differ between these two regions. In total, 20% of blood samples were PCR-positive for <italic>A. phagocytophilum</italic>. Serological analyses showed that 33% of all collected samples were positive for <italic>A. phagocytophilum</italic>, while 2.5% were positive for <italic>Borrelia burgdorferi</italic> s.l. and 13% for tick-borne encephalitis virus (TBEV). Percentages of lambs positive were 75 and 45% for <italic>A. phagocytophilum</italic> antibodies and DNA, respectively, while 10 and 45% were serologically positive for <italic>B. burgdorferi</italic> s.l. and TBEV, respectively. Sequencing of partial 16S rRNA genes from <italic>Anaplasma</italic> PCR positive samples revealed presence of <italic>A. phagocytophilum</italic> in all animals in Östergötland, while sequences consistent with <italic>A. phagocytophilum</italic> as well as <italic>A. capra</italic> and <italic>A. bovis</italic> were found on the island of Gotland. This is the first report of the occurrence of the latter two species in Sweden.</p>