| dc.description.abstract | Southern Africa has the highest diversity of reptile fauna in Africa. Despite estimates that diversity of reptile associated haematozoans are higher compared to mammals and birds, there is a lack of research regarding Apicomplexans infecting reptiles. The overall aim of this research was to assess the diversity of apicomplexan haematozoans in a subset of snakes and terrapins of South Africa, whilst demonstrating the potential limiting effects that fragmentary studies, relating to the topic, has on progressing research. In order to achieve this aim with a sampling pool encompassing captive and wild snakes, as well as terrapins, different factors had to be taken into account that can influence the diversity of apicomplexan haematozoans infecting these hosts. Therefore, a variety of research tools, including microscopic, molecular and phylogenetic analyses as well as predictive distribution modelling were utilized to assess the diversity of these parasites. A total of 154 snakes of the Limpopo, Mpumalanga and KwaZulu-Natal provinces (82 wild, 62 captive) of five genera and 7 species were sampled and screened for the presence of species of Hepatozoon and Haemocystidium. Hepatozoon spp. were found infecting all of the sampled snake species (Dendroaspis polylepis; Dendroaspis angusticeps; Dispholidus typus; Bitis arietans; Naja mossambica; Naja annulifera and Python natalensis natalensis). Genetic analyses indicated that there were two Hepatozoon spp., referred to as Hepatozoon sp. A and Hepatozoon sp. B. Hepatozoon sp. A, comprised four morphotypes, and was found infecting 6/7 (86%) of species of snakes and 32/154 (21%) of individuals collected, while Hepatozoon sp. B, comprised one morphotype, and was found infecting four individuals of one snake species, Di. typus, as such 1/7 (14%) of snake species and 4/154 (2%) of snakes collected. Of the sampled snake species, only the two sampled cobra species (N. mossambica and N. annulifera) had positive infections with Haemocystidium mesnili, based on phylogenetic analysis, suggesting that this species displays host-specificity towards cobra species. The overall prevalence in N. mossambica was 8/28 (28.6%) and for N. annulifera the overall prevalence was 2/30 (6.7%). Although phylogenetic analysis indicated that this species is Haemocystidium mesnili, the identification of this species cannot be certain as the only available sequence of this species in GenBank is not accompanied by morphological data, even though this data was available for H. mesnili at the time the sequence was deposited. It was also discovered that both Hepatozoon and Haemocystidium infections in captive snakes, which were once wild, became infected with
these parasites in the wild, and that the successful infection of a host by the parasite is likely associated with the ecology of snakes in the wild. Both Hepatozoon and Haemocystidium were observed in captive snakes that were isolated from vectors and where dietary infection routes were absent, as these snakes were kept indoors in enclosed enclosures, were screened for ectoparasites before they were moved to captivity and were only fed captive bred prey items. These snakes were in captivity for up to three years, suggesting that these parasites can persist in the system of their hosts for a long duration of time. The overall prevalence and parasitaemia for Hepatozoon spp. was higher for wild snakes than for captive snakes, with a prevalence of 35/82 (42.7%) and parasitaemia of 0.01–9.3% recorded in wild, as compared to a prevalence of 16/62 (25.8%) and parasitaemia of 0.01–7.7% in captive snakes. There were no clear differences between the prevalence of Haemocystidium mesnili in wild and captive snakes, with a prevalence of 6/20 (30%) for wild and 2/8 (25%) for captive N. mossambica and 1/20 (5%) for wild and 1/10 (10%) for captive N. annulifera. The overall parasitaemia for Haemocystidium was higher in wild cobras compared to captive cobras, where in captive it ranged from 0.20 to 1.75% and in wild it ranged from 0.40–19.00%.
Terrapins (Pelomedusa galeata and Pelusios sinuatus), were infected with Haemogregarina spp., where Pe. galeata individuals were collected from North-West with a prevalence of 19/20 (95%) and KwaZulu-Natal 6/6 (100%) and P. sinuatus individuals were only collected from KwaZulu-Natal with a prevalence of 13/14 (93%). Positive infections in Pe. galeata were confirmed based on both microscopy and molecular analyses, whereas positive infections in P. sinuatus were only based on microscopy as the amplification process from the samples failed. In order to assess the distribution of Haemogregarina spp. infecting terrapins, predictive distribution modelling with the use of available distribution data of Haemogregarina spp. infecting southern African terrapins and available distribution data for the leech Placobdella multistriata were obtained and utilised in Maxent. The predicted distribution indicated that terrapin associated Haemogregarina spp. occur across a wide variety of environmental paramaters, which likely results from the wide distribution of both the vertebrate and invertebrate hosts. Therefore, it is considered that Haemogregarina spp. infecting terrapins have a wider distribution than what is displayed by the currently available distribution records, suggesting that the range of the predicted distribution might expand as more distribution records for Haemogregarina spp. are made available. | en_US |
