Ultrastructural Comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), Parasitising South African Anurans

PREVALENCE AND PARASITE INTENSITY OF HAEMOGREGARINES IN AFRICAN BELL HINGE-BACK (KINIXYS BELLIANA) AND AFRICAN HOME'S HINGE-BACK (KINIXYS HOMEANA) TORTOISES IN IBADAN, NIGERIA

Haemogregarines are a group of intracellular blood parasites reported in reptiles, other vertebrate taxa including mammals and fish, and haematophagous invertebrates. Information on prevalence, biodiversity, and host-specificity of haemogregarines of tortoises in Nigeria are scarce. A total of 120 African hinge-back tortoises (Kinixys belliana, n=70, and K. homeana, n=50) were bought from the Wildlife and Herbal Market in Ibadan, Nigeria. Blood was withdrawn via the subcarapacial sinuses of each tortoise. The prevalence and parasite intensity of haemogregarine infection was determined using a light microscope, and parasite species were determined by PCR using HepF300 and HepR900 primers. A sequence of 654 base pairs (bp; Hepatozoon cf. fitzsimonsi) from the study aligned with published 18SrRNA and closely related with a similarity of 97.38% to Hepatozoon fitzsimonsi sequenced from Kinixys zobensis in South Africa. Overall prevalence of haemogregarines was 53.33% from light microcopy and 75.83% from PCR, which is considered very high. Higher prevalence and mean±SD parasite intensity were recorded for K. belliana (82.89%, 0.29%) than for K. homeana (66.00%, 0.26%). Prevalence rates and parasite intensities of haemogregarines were significantly higher in wet than in dry seasons. The differences in prevalence and intensity between and within species may be due to habitat characteristics, feeding habits of vectors and hosts, seasons, and vector abundance.

Blood parasites in sympatric lizards: what is their impact on hosts’ immune system?

Assessment of parasites and their pathogenicity is essential for studying the ecology of populations and understanding their dynamics. In this study, we investigate the prevalence and intensity of infection of haemogregarines (phylum Apicomplexa) in two sympatric lizard species, Podarcis vaucheri and Scelarcis perspicillata, across three localities in Morocco, and their effect on host immune response. We used the Phytohaemagglutinin (PHA) skin testing technique to relate the level of immune response with parasite infection. Prevalence and intensity levels were estimated with microscopy, and 18S rRNA gene sequences were used to confirm parasite identity. All parasites belong to the haemogregarine lineage found in other North African reptiles. There were differences in prevalence between localities and sexes. Overall, infected lizards were larger than uninfected ones, although we did not detect differences in parasitaemia across species, sex or locality. The swelling response was not related to the presence or number of haemogregarines, or to host body size, body condition, sex or species. We found no evidence of impact for these parasites on the circulating blood cells or the hosts’ immune system, but more data is needed to assess the potential impact of mixed infections, and the possibility of cryptic parasite species.

An update on the mosquito fauna and mosquito-borne diseases distribution in Cameroon

The expansion of mosquito-borne diseases such as dengue, yellow fever, and chikungunya in the past 15 years has ignited the need for active surveillance of common and neglected mosquito-borne infectious diseases. The surveillance should be designed to detect diseases and to provide relevant field-based data for developing and implementing effective control measures to prevent outbreaks before significant public health consequences can occur. Mosquitoes are important vectors of human and animal pathogens, and knowledge on their biodiversity and distribution in the Afrotropical region is needed for the development of evidence-based vector control strategies. Following a comprehensive literature search, an inventory of the diversity and distribution of mosquitoes as well as the different mosquito-borne diseases found in Cameroon was made. A total of 290 publications/reports and the mosquito catalogue website were consulted for the review. To date, about 307 species, four subspecies and one putative new species of Culicidae, comprising 60 species and one putative new species of Anopheles, 67 species and two subspecies of Culex, 77 species and one subspecies of Aedes, 31 species and one subspecies of Eretmapodites, two Mansonia, eight Coquillettidia, and 62 species with unknown medical and veterinary importance (Toxorhynchites, Uranotaenia, Mimomyia, Malaya, Hodgesia, Ficalbia, Orthopodomyia, Aedeomyia, and Culiseta and Lutzia) have been collected in Cameroon. Multiple mosquito species implicated in the transmission of pathogens within Anopheles, Culex, Aedes, Eretmapodites, Mansonia, and Coquillettidia have been reported in Cameroon. Furthermore, the presence of 26 human and zoonotic arboviral diseases, one helminthic disease, and two protozoal diseases has been reported. Information on the bionomics, taxonomy, and distribution of mosquito species will be useful for the development of integrated vector management programmes for the surveillance and elimination of mosquito-borne diseases in Cameroon.

Description of a New Species Hepatozoon quagliattus sp. nov. (Apicomplexa: Adeleorina: Hepatozoidae), infecting the Sleep Snake, Dipsas mikanii (Squamata: Colubridae: Dipsadinae) from Goiás State, Brazil

PURPOSE

Species of Hepatozoon Miller, 1908 (Hepatozoidae) are blood protozoans with a cosmopolitan distribution and are reported to parasitize a range of vertebrate hosts including mammals, birds, reptiles, and amphibians. The present study aimed to describe a new species of Hepatozoon (Apicomplexa: Adeleorina: Hepatozoidae) found infecting the sleep snake Dipsas mikanii (Schlegel, 1837) (Squamata: Colubridae: Dipsadinae).

METHODS

The snake was collected in 2017 at the municipality of Britânia, Goiás State, Brazil. Blood smears were made in order to find blood gametocytes and PCR was performed targeting the 18S rRNA gene.

RESULTS

Microscopy screening of blood smears revealed the presence of intraerythrocytic gamont stages of Hepatozoon sp. in the peripheral blood with a parasitemia of 0.25%. Furthermore, meronts and monozoic cysts were observed in histological sections of the liver from the infected individual. The interspecific divergence of 18S rRNA sequences fragments isolated from D. mikanii had differences (2.39-11.3%) as compared to other sequences of species of Hepatozoon from snakes.

CONCLUSIONS

Based on morphological and molecular data, a new species of Hepatozoon infecting D. mikanii from Brazil is described.

Against growing synonymy: Identification pitfalls of Hepatozoon and Schellackia demonstrated on North Iranian reptiles

The analyses of molecular data represent an effective tool for increasing the credibility of taxonomy and facilitate the description of species. Nevertheless, in haemoprotozoa, the growing amount of available sequential data is not matched by the still limited number of well-defined species. We identified four protistan haemoparasites in North Iranian reptiles: two Hepatozoon and two Schellackia species. Hepatozoon colubri and Hepatozoon ophisauri were morphologically identified in their type hosts, their partial 18S rDNA was analyzed, and thorough literature data were included in their redescription. The scarce data on the detected Schellackia spp. did not allow for their formal species description. Using an integrative approach, including morphological and geographical features, host specificity, molecular data, and the data published thus far, we face the following main difficulties hindering reliable diagnosis. (1) The lack of molecular data on well-described and named species. (2) The insufficiency of using only morphological and biological features, or only sequential data without morphology, to perform an absolutely reliable species diagnosis. (3) Typical morphological features are more substantial than metric means. (4) High risk of synonymy is present in taxonomy of blood Protista. (5) Artefacts caused by blood smear processing further complicate the correct morphological determination.

Haemogregarines and Criteria for Identification

Simple Summary

Taxonomic classification of haemogregarines belonging to Apicomplexa can become difficult when the information about the life cycle stages is not available. Using a self-reporting, we record different haemogregarine species infecting various animal categories and exploring the most systematic features for each life cycle stage. The keystone in the classification of any species of haemogregarines is related to the sporogonic cycle more than other stages of schizogony and gamogony. Molecular approaches are excellent tools that enabled the identification of apicomplexan parasites by clarifying their evolutionary relationships.

Abstract

Apicomplexa is a phylum that includes all parasitic protozoa sharing unique ultrastructural features. Haemogregarines are sophisticated apicomplexan blood parasites with an obligatory heteroxenous life cycle and haplohomophasic alternation of generations. Haemogregarines are common blood parasites of fish, amphibians, lizards, snakes, turtles, tortoises, crocodilians, birds, and mammals. Haemogregarine ultrastructure has been so far examined only for stages from the vertebrate host. PCR-based assays and the sequencing of the 18S rRNA gene are helpful methods to further characterize this parasite group. The proper classification for the haemogregarine complex is available with the criteria of generic and unique diagnosis of these parasites.

An overview of the Dactylosomatidae (Apicomplexa: Adeleorina: Dactylosomatidae), with the description of Dactylosoma kermiti n. sp. parasitising Ptychadena anchietae and Sclerophrys gutturalis from South Africa

Haemogregarine (Apicomplexa: Adeleorina) blood parasites are commonly reported from anuran hosts. Dactylosomatidae (Jakowska and Nigrelli, 1955) is a group of haemogregarines comprising Dactylosoma Labbé, 1894 and Babesiosoma Jakowska and Nigrelli, 1956. Currently Dactylosoma and Babesiosoma contain five recognised species each. In the current study, a total of 643 anurans, comprising 38 species, 20 genera, and 13 families were collected from South Africa (n = 618) and Belgium (n = 25), and their blood screened for the presence of dactylosomatid parasites. Three anuran species were found infected namely, Ptychadena anchietae (Bocage, 1868) and Sclerophrys gutturalis (Power, 1927) from South Africa, and Pelophylax lessonae (Camerano, 1882) from Belgium. Based on morphological characteristics, morphometrics and molecular results a new dactylosomatid, Dactylosoma kermiti n. sp. is described form Pty. anchietae and Scl. gutturalis. The species of Dactylosoma isolated from Pel. lessonae could not, based on morphological or molecular analysis, be identified to species level. Phylogenetic analysis shows species of Dactylosoma infecting anurans as a monophyletic group separate from the other haemogregarine groups. Additionally, the mosquitoes Uranotaenia (Pseudoficalbia) mashonaensis Theobald, 1901 and U. (Pfc.) montana Ingram and De Meillon, 1927 were observed feeding on Scl. gutturalis in situ and possible dividing stages of this new parasite were observed in the mosquitoes. This study is the first to describe a dactylosomatid parasite based on morphological and molecular data from Africa as well as observe potential stages in possible dipteran vectors.

Neofoleyellides boerewors n. gen. n. sp. (Nematoda: Onchocercidae) parasitising common toads and mosquito vectors: morphology, life history, experimental transmission and host-vector interaction in situ

Anuran filarial nematodes are restricted to two comparatively small subfamilies (Icosiellinae and Waltonellinae) of the filariae that currently comprise six genera and 41 recognised species. However, the life histories of only five anuran filarial nematodes, proposed as an ancestral group based on molecular phylogenetic studies, have been elucidated. Furthermore, data on the natural vectors (in situ) and parasite transmission is limited. In the current study we elucidate the life history of Neofoleyellides boerewors n. gen. n. sp. parasitising the guttural toad, Sclerophrys gutturalis and the mosquito vectors Uranotaenia (Pseudoficalbia) mashonaensis and Uranotaenia (Pseudoficalbia) montana. Additionally, we report on the unique host-seeking behaviour of the mosquito vectors which locate their toad hosts using their calls. The complex host-vector relationship and specialised host-seeking behaviour by these mosquitoes indicate biases towards host species and male toad infections.

Diversity of Karyolysus and Schellackia from the Iberian lizard Lacerta schreiberi with sequence data from engorged ticks

Apicomplexan haemoparasites of the genera Schellackia Reichenow, 1919, and Karyolysus Labbé, 1894, seem to be common in lizards and widespread across the world. For decades, their identification has been based on morphological descriptions and life cycle patterns, with molecular characterizations, applied only recently. We used molecular characterization to confirm the identification of haemoparasites detected by microscopy in blood smears of Lacerta schreiberi Bedriaga, 1878, a lizard of the Iberian Peninsula. Since blood samples other than blood smears were not available from the studied lizards, 264 engorged ticks Ixodes ricinus (Linneaus, 1758) collected from them were used as an alternative non-invasive source of haemoparasite DNA for molecular genetic analyses. Of the 48 blood smears microscopically examined, 31 were positive for blood parasites (64.6% prevalence). We identified trophozoites and gamonts similar to Karyolysus lacazei (Labbé, 1894) (24/48; 50%) and Schellackia-like sporozoites (20/48; 41.7%). Mixed infections with both species occurred in 13 blood smears (27.1%). Sequence data were obtained for both parasites from engorged ticks. Phylogenetic analyses placed our unique haemogregarine sequence within the Karyolysus clade, nevertheless, within substantial polytomy. Thus, according to its morphology and effect on the host cell, we refer to this haemogregarine as Karyolysus cf. lacazei. Besides the Schellackia sequences being identical to a previously identified haplotype, we also obtained sequences of three new closely related haplotypes.

Monophyly of the species of Hepatozoon (Adeleorina: Hepatozoidae) parasitizing (African) anurans, with the description of three new species from hyperoliid frogs in South Africa

Haemogregarines (Apicomplexa: Adeleiorina) are a diverse group of haemoparasites reported from almost all vertebrate classes. The most commonly recorded haemogregarines to parasitize anurans are species of Hepatozoon Miller, 1908. To date 16 Hepatozoon species have been described from anurans in Africa, with only a single species, Hepatozoon hyperolli (Hoare, 1932), infecting a member of the Hyperoliidae. Furthermore, only two Hepatozoon species are known from South African anurans, namely Hepatozoon theileri (Laveran, 1905) and Hepatozoon ixoxo Netherlands, Cook and Smit, 2014, from Amietia delalandii (syn. Amietia quecketti) and three Sclerophrys species, respectively. Blood samples were collected from a total of 225 individuals representing nine hyperoliid species from several localities throughout northern KwaZulu-Natal, South Africa. Twenty frogs from three species were found positive for haemogregarines, namely Afrixalus fornasinii (6/14), Hyperolius argus (2/39), and Hyperolius marmoratus (12/74). Based on morphological characteristics, morphometrics and molecular findings three new haemogregarine species, Hepatozoon involucrum Netherlands, Cook and Smit n. sp., Hepatozoon tenuis Netherlands, Cook and Smit n. sp. and Hepatozoon thori Netherlands, Cook and Smit n. sp., are described from hyperoliid hosts. Furthermore, molecular analyses show anuran Hepatozoon species to be a separate monophyletic group, with species isolated from African hosts forming a monophyletic clade within this cluster.