Molecular and Serological Detection of Piroplasms in Horses from Nigeria

Abstract

Equine piroplasmosis, an economically important disease of equids caused by the hemoprotozoan parasites Theileria equi, T. haneyi, and Babesia caballi, has a worldwide distribution. These parasites are transmitted by ixodid ticks. To improve the detection of horses in Nigeria exposed to piroplasm parasites, 72 horses with variable clinical signs of piroplasmosis were sampled from Northwest and Northcentral Nigeria and tested by nPCR and cELISA. Blood and serum samples were collected from each horse via jugular venesection. Individually, nPCR or cELISA failed to identify all horses exposed to piroplasms. A combination of species-specific nPCR and the OIE-approved T. equi and B. caballi cELISAs enhanced the detection of horses exposed to parasites. The results also demonstrated horses showing abnormal hematology were positive for only T. equi, except for one sample that was coinfected with T. equi and T. haneyi. We also identified ticks collected from some of the horses, with Rhipicephalus evertsi evertsi being the most prevalent. This study shows that a larger proportion of horses in the sample set were exposed to T. equi than B. caballi or T. haneyi. Additionally, ticks that have been previously reported as potential vectors for these parasites were found to have infested sampled horses. Further studies are needed to investigate which tick species are competent vectors for Theileria spp. and Babesia caballi in Nigeria.

Seroprevalence of Anti-Theileria equi Antibodies in Horses from Three Geographically Distinct Areas of Romania

“…Contrary to these results, other investigations revealed that older animals were more likely to be seropositive for T. equi [22][23][24][25][26][27][28][29][30]. Gender as a risk factor varied even more among study results, with some studies stating that females were more commonly infected, while other studies stated the opposite [26,31].…”

“…The movement of horses between countries or different regions can contribute to wider spreading of new species of parasites [31,48], and understanding horse infections can help prevent this phenomenon.…”

Molecular and Serological Detection of Vector-Borne Pathogens Responsible for Equine Piroplasmosis in Europe between 2008 and 2021

“…Epidemiological studies in horses have consistently reported lower detection rates by means of molecular than serological methods [51][52][53][54]. Especially for T. equi, antibody [49]).…”

Spatial and Temporal Circulation of Babesia caballi and Theileria equi in France Based on Seven Years of Serological Data

“…Even though antibodies persist for months or years after infection, thereby smoothing the effect of seasonality in transmission and not being adapted to detect ongoing infection in individuals, serological data represent cumulative exposure to the parasites and are widely used to monitor transmission intensity and dynamics of infectious diseases, as well as to identify high-risk groups or high-risk regions, including for equine piroplasmosis [11,20,21]. In fact, there is a direct relationship between antibody titres against B. caballi or T. equi and parasitaemia in horses [9,22], although studies have generally shown that prevalence measured based on parasite detection is lower than seroprevalence [23][24][25][26]. This difference can be attributed to the lack of sensitivity of PCR-based methods, which are designed to detect the parasites at amounts below the detection threshold (in the peripheral blood) in asymptomatic carriers or in equids having received treatment that reduces parasitaemia.…”