Anaplasma marginale subsp. infection

Sisson, Danielle, Beechler, Brianna, Jabbar, Abdul, Jolles, Anna & Hufschmid, Jasmin, 2023, Epidemiology of Anaplasma marginale and Anaplasma centrale infections in African buffalo (Syncerus caffer) from Kruger National Park, South Africa, International Journal for Parasitology: Parasites and Wildlife 21, pp. 47-54 : 50

3.3. A. marginale infection presence peaks earlier than A. centrale

Fifteen calves who were under the age of 6 months at the first capture were analysed for the order of infection. Fourteen of them were first positive for A. marginale , while the remaining calf was first coinfected with A. marginale and A. centrale . Five calves were infected with A. marginale on their first capture after birth, with a mean age of 3.4 months of age (SD = 0.202, Chi-square test: p <0.001, X 2 = 13.133). By the time the calves turned six months of age, the overall prevalence of infection with A. centrale was 40% and 100% for A. marginale . The average age of initial A. marginale infection was eight months (SD = ± 6 months), whereas that for A. centrale was 17 months (SD = ± 14 months).

Younger animals were more likely to test positive for the presence of A. marginale (p = <0.001) ( Table 2; Fig. 1 ; Supplementary Table 3). Infection intensities of both A. marginale and A. centrale decreased significantly with increasing age (p = 0.004 and p = 0.043, respectively) ( Table 2; Fig. 3a ; Supplementary Table 4). So while A. marginale infection peaks earlier than A. centrale , both decline in adult and geriatric buffalo.

Figures

Fig. 1. The proportion of animals infected with Anaplasma spp. from a managed African buffalo (Syncerus caffer) herd from Kruger National Park, South Africa. a) The mean prevalence of animals with A. marginale single infection, A. centrale single infection, or co-infections with each other over four age groups: calves (0–1 years old), sub-adults (1–5.5 years old), adults (5.5–15 years) and geriatrics (15 years plus); b) the mean prevalence of new infections with A. marginale or A. centrale for each capture event over the two-and-a-half-year study period. Numbers at the top of figure represent sample size.

Fig. 3. Patterns of infection with Anaplasma spp. based on age and sex for a managed African buffalo (Syncerus caffer) herd from Kruger National Park, South Africa. a) The infection intensity (log-transformed number of copies/reaction) of A. marginale and A. centrale based on age (years); b) overall proportion of animals infected with A. marginale or A. centrale based on sex; c) infection intensity (log-transformed number of copies/reaction) results for A. marginale or A. centrale based on sex. * indicates statistical significance (p <0.05). Error bars are standard error.