Prevalence and diversity of piroplasms and ticks in young raccoons and an association of Babesia sensu stricto infections with splenomegaly

Abstract

Piroplasms are intraerythrocytic parasites that are often transmitted by ixodid ticks, but vertical transmission is an alternative route for some species. In the USA, raccoons (Procyon lotor) are hosts for two known species, a Babesia microti-like sp. and Babesia lotori (in Babesia sensu stricto group). To better understand the natural history of Babesia in raccoons, we tested young raccoons from Minnesota and Colorado for Babesia spp., examined them for ticks, and assessing for splenomegaly as a sign of clinical disease. Raccoons from both states were infected with B. microti-like sp. and Babesia sensu stricto spp. Infections of B. microti-like were common, even in 1-week-old raccoons, suggesting vertical transmission. Babesia sensu stricto infections were more common in older raccoons. Raccoons infected with Babesia sensu stricto had significantly higher spleen:body weight ratios compared with uninfected or B. microti-like sp.-infected raccoons. Ticks were only found on raccoons from Minnesota. The most common and abundant tick was Ixodes texanus but Ixodes scapularis and Dermacentor variabilis were also found on raccoons. We report piroplasm infections and infestations with several tick species in very young raccoons. Young raccoons infected with Babesia sensu stricto spp. had higher spleen:body weight ratios, suggesting a disease risk.

Prevalence, distribution, and diversity of cryptic piroplasm infections in raccoons from selected areas of the United States and Canada

“…A recent study on piroplasms in young raccoons also show similar evidence, with multiple species of B. s. s. being present in young raccoons, and a possible association of disease (splenomegaly). However, due to low sample sizes of the various B. s. s. species in young raccoons there was insufficient data to assess which B. s. s. species was causing splenomegaly in the young raccoons (Garrett et al, 2018). The data from both this study and Garrett et al, (2018) highlight the need to conduct sequence analysis when using genus- or group-wide molecular assays to confirm or identify the species detected.…”

“…An additional study on piroplasms in young raccoons from Minnesota had evidence of clinical disease (splenomegaly) associated with B. s.s . infections in young raccoons (Garrett et al, 2018). Thus, parasites of raccoons are of particular interest because of this evidence of possible disease in raccoons and other hosts coupled with a large natural geographic range within North America, established introduced populations in numerous European and Asian countries, and their ability to utilize a diversity of habitat types, including both urban and suburban areas.…”

Invasive raccoon (Procyon lotor) and raccoon dog (Nyctereutes procyonoides) as potential reservoirs of tick-borne pathogens: data review from native and introduced areas

“…B. lotori , B. microti -like, a novel Babesia s.s. and a novel western Babesia sp.) with an additional fifth species found only in the Japanese population of raccoons [ 36 , 37 ]. Babesia microti -like was the most common piroplasm detected in raccoons from the USA.…”

“…which most closely resembles Babesia sp. AJB-1006 detected in a raccoon in Illinois [ 36 , 37 , 39 – 41 ]. Babesia lotori (previously referred to as Babesia s.s. and Babesia sp.…”

“…Babesia lotori (previously referred to as Babesia s.s. and Babesia sp. AJB-2006) has been found in a single raccoon from Illinois that had clinical symptoms, and in raccoons from Minnesota and Colorado, North Carolina and various other states in the USA [ 36 , 37 , 40 , 42 ]. No data on potential tick vectors for any Babesia spp.…”