Haemogregarine blood parasites in the lizards Podarcis bocagei (Seoane) and P. carbonelli (Pérez-Mellado) (Sauria: Lacertidae) from NW Portugal

Molecular characterization of haemosporidian and haemogregarine diversity in southwestern Iberian amphibians and reptiles

The knowledge of the diversity and geographic distribution of parasite species is the first step towards understanding processes of global epidemiology and species conservation. Despite recent increases in research on haemosporidian and haemogregarine parasites of reptiles and amphibians, we still know little about their diversity and parasite-host interactions, especially in the Iberian Peninsula, where a few studies have been conducted. In this study, the haemosporidian and haemogregarine diversity and phylogenetic relationships of the parasites in southwestern Iberian amphibians and reptiles were assessed using PCR approaches on blood samples of 145 individuals from five amphibian and 13 reptile species. The amphibians did not present any of both groups of parasites studied. Regarding reptiles, five Hepatozoon, one Haemogregarina, and one Haemocystidum haplotypes were found infecting four different species, revealing new host records for these parasites. Among them, we found one new Haemocystidium haplotype and three new and a previously reported Hepatozoon haplotype from a north African snake. The latter finding suggests that some Hepatozoon parasites may not be host-specific and have large geographic ranges even crossing geographical barriers. These results increased the knowledge about the geographic distribution and the number of known host species of some reptile apicomplexan parasites, highlighting the great unexplored diversity of them in this region.

Biological responses in pesticide exposed lizards (Podarcis siculus)

The release of contaminants as herbicides, fungicides and insecticides into the environment has been listed as one of the six major contributors to the global decline of reptiles. Although reptiles may face severe risk from contaminants due to their ecology and physiology, they are currently less studied than other vertebrate groups. In the present work, we investigated if and how different types of field treatment (conventional and organic) affected the health status of Italian wall lizard (Podarcis siculus) individuals in central Italy. We chose a multi-biomarker approach that evaluated the biological responses of lizards to the treatment by means of AChE activity in the nervous system, biotransformation enzymes activities and oxidative stress in the liver, micronuclei frequency measured in the erythrocytes, and rate of intestinal parasitic infection. Our findings showed evidence of effects of treatment in conventional areas and between sexes with significant oxidative stress due to hydroxyl radicals, that caused DNA damage. No difference of intestinal parasite infections was found among treatments. Podarcis siculus seems to be a good bioindicator in ecotoxicological studies and potentially in risk assessment of pesticides, although further analyses in laboratory and in the field are needed to achieve more accurate quantification of specific pesticide effects in relation to known exposure history and to understand if other mechanisms were involved in the toxicity and detoxification process of pesticides for this species.

Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body condition and sex as intrinsic predictors. Linear models based on robust estimates were fitted to analyse parasite abundance and prevalence. Ectoparasitic mites and blood parasites from two haemococcidian genera were found: Lankesterella spp. and Schellackia spp. Habitat type was the only predictor explaining the abundance of all parasites, being mostly higher in the forest than in the dunes. The results suggest that particularities in each host–parasite relationship should be accounted even when parasites infect close-related hosts under the same environmental pressures. They also support that lizard parasites can be biomarkers of environmental perturbation, but the relationships need to be carefully interpreted for each host–parasite assemblage.

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.

Hepatozoon pyramidumi sp. n. (Apicomplexa: Adeleorina) from the blood of Echis pyramidum: morphology and SSU rDNA sequence

Hepatozoon pyramidumi sp. n. is described from the blood of the Egyptian saw-scaled viper, Echis pyramidum, captured from Saudi Arabia. Five out of ten viper specimens examined (50%) were found infected with Hepatozoon pyramidumi sp. n. with parasitaemia level ranged from 20-30%. The infection was restricted only to the erythrocytes. Two morphologically different forms of intraerythrocytic stages were observed; small and mature gamonts. The small ganomt with average size of 10.7 × 3.5 μm. Mature gamont was sausage-shaped with recurved poles measuring 16.3 × 4.2 μm in average size. Infected erythrocytes were hypertrophied; their nuclei were deformed and sometimes displaced from their central position in the normal uninfected cell. Merogonic stages were observed in the lung endothelial cell and the liver parenchyma cells. Mature meront was 17.8 × 13.6 µm and contained banana-shaped merozoites with average size of ~15 × 2 µm. Phylogenetic analysis based on the SSU rDNA sequence clustered Hepatozoon pyramidumi sp. n with previously sequenced Hepatozoon spp., most of them infected reptilian hosts without geographic consideration. The morphological and molecular comparison with closely related species proved the taxonomic uniqueness and novelty of the present form.

Infection Patterns of Helminths in Norops Brasiliensis (Squamata, Dactyloidae) from a Humid Forest, Northeastern Brazil and their Relation with Body Mass, Sex, Host Size, and Season

Climatic and ecological factors can influence the parasite load of a host. Variation in rainfall, body size, and sex of the hosts may be related to the abundance of parasites. This study investigated the helminth fauna associated with a population of Norops brasiliensis, together with the effect of host biology (sex, body size, and mass) and variation in rainfall regime on the abundance of helminths. Species of three groups of endoparasites were found (Nematoda, Cestoda, and Trematoda), with nematodes as the most representative taxa with eight species, prevalence of 63.2 %, mean intensity of 4.0 ± 0.58 (1 – 25), and mean abundance of 2.66 ± 0.44 (0 – 25). Nine helminth species are new host records for N. brasiliensis. The nematode Rhabdias sp. had the highest prevalence (53.3 %). There was no signifi cant relationship between abundance of the trematode Mesocoelium monas and host sex or season, although the abundance of this parasite increased significantly with host body size and mass, while abundance of nematodes was related to season and host mass. This study increases the knowledge about the diversity of helminth fauna associated with N. brasiliensis, revealing infection levels of hosts from northeastern Brazil.

Prevalence and Levels of Parasitemia of Hepatozoon sp. (Apicomplexa: Adeleorina) in Four Gopher Tortoise (Gopherus polyphemus) Populations of South FLORIDA, USA

Hepatozoon prevalence (occurrence) and parasitemia (intensity) levels were documented in 67 individuals of the threatened gopher tortoise (Gopherus polyphemus) for the first time in four South Florida, US, locations: Jonathan Dickinson State Park (JDSP), Pine Jog Preserve (PJP), Florida Atlantic University Preserve (FAUP), and Blazing Star Preserve (BSP). Sex ratios (males:females) per site were 0.44 at JDSP, 0.72 at PJP, 1.42 at FAUP, and 0.40 at BSP, but no significant differences in the carapace length were found between the two sexes (independent t-test; P=0.101). Hepatozoon sp. was found in 13% (9/67) of tortoises. Percentages of infected tortoises were 22% (5/23) males and 6% (2/33) females. Prevalence and parasitemia were low or nonexistent within sampled tortoises at each of the study sites, although the highest prevalence and parasitemia values were found in gopher tortoises at JDSP (23%, 4/17) which also harbored the highest infection levels, reaching 349/10,000 erythrocytes. No infection was detected within sampled gopher tortoises at PJP.

Effects of parasitic infection and reproduction on corticosterone plasma levels in Galápagos land iguanas, Conolophus marthae and C. subcristatus

In vertebrates, one main feature of stress response is the release of glucocorticoids (corticosterone in reptiles), steroid hormones whose synthesis is regulated by the hypothalamic-pituitary-adrenal axis (HPA). In the Galápagos Islands, populations of land iguanas are differentially impacted by a tick-transmitted apicomplexan hemoparasite of genus Hepatozoon, which could cause diseases and ultimately reduce fitness. Using competitive enzyme-linked immunosorbent assays (ELISA), we examined baseline plasma corticosterone levels of two syntopic and highly parasitized populations of the land iguana species Conolophus marthae and C. subcristatus in Wolf volcano (Isabela Island). We also used a poorly parasitized population of C. subcristatus from the same island (Bahia Urbina) as a reference. To better interpret the observed glucocorticoids patterns, we simultaneously performed the count of white blood cells (WBCs) in all individuals and investigated the reproductive status of females. We did not find evidence in support of either a positive or negative relationship between the tick load, hemoparasite infection, and glucocorticoid plasma concentration in C. marthae and C. subcristatus at Wolf volcano. The comparison between parasitized and non-parasitized sites (V. Wolf and Bahia Urbina) would instead suggest an inverse relationship between corticosterone and parasites. Our findings support association between corticosterone plasma levels and reproduction.

Morphological and molecular characterization of Karyolysus--a neglected but common parasite infecting some European lizards

Background

Blood parasites of the genus Karyolysus Labbé, 1894 (Apicomplexa: Adeleida: Karyolysidae) represent the protozoan haemogregarines found in various genera of lizards, including Lacerta, Podarcis, Darevskia (Lacertidae) and Mabouia (Scincidae). The vectors of parasites are gamasid mites from the genus Ophionyssus.

Methods

A total of 557 individuals of lacertid lizards were captured in four different localities in Europe (Hungary, Poland, Romania and Slovakia) and blood was collected. Samples were examined using both microscopic and molecular methods, and phylogenetic relationships of all isolates of Karyolysus sp. were assessed for the first time. Karyolysus sp. 18S rRNA isolates were evaluated using Bayesian and Maximum Likelihood analyses.

Results

A total of 520 blood smears were examined microscopically and unicellular protozoan parasites were found in 116 samples (22.3% prevalence). The presence of two Karyolysus species, K. latus and K. lacazei was identified. In total, of 210 samples tested by polymerase chain reaction (PCR), the presence of parasites was observed in 64 individuals (prevalence 30.5%). Results of phylogenetic analyses revealed the existence of four haplotypes, all part of the same lineage, with other parasites identified as belonging to the genus Hepatozoon.

Conclusions

Classification of these parasites using current taxonomy is complex - they were identified in both mites and ticks that typically are considered to host Karyolysus and Hepatozoon respectively. Furthermore although distortions to the intermediate host erythrocyte nuclei were observed, the defining characteristic of Karyolysus, the haplotypes were nearly identical to those reported from lizards in the Iberian Peninsula, where such distortions were not reported and which were thus identified as Hepatozoon. Based on the phylogenetic analyses, neither vertebrate host, nor geographical patterns of the studied blood parasites could be established.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-014-0555-x) contains supplementary material, which is available to authorized users.

Blood parasites in reptiles imported to Germany

Though international trade is increasing, the significance of imported reptiles as carriers of pathogens with relevance to animal and human health is largely unknown. Reptiles imported to Germany were therefore investigated for blood parasites using light microscopy, and the detected parasites were morphologically characterized. Four hundred ten reptiles belonging to 17 species originating from 11 Asian, South American and African countries were included. Parasites were detected in 117 (29%) of individual reptiles and in 12 species. Haemococcidea (Haemogregarina, Hepatozoon, Schellackia) were found in 84% of snakes (Python regius, Corallus caninus), 20% of lizards (Acanthocercus atricollis, Agama agama, Kinyongia fischeri, Gekko gecko) and 50% of turtles (Pelusios castaneus). Infections with Hematozoea (Plasmodium, Sauroplasma) were detected in 14% of lizards (Acanthocercus atricollis, Agama agama, Agama mwanzae, K. fischeri, Furcifer pardalis, Xenagama batillifera, Acanthosaura capra, Physignathus cocincinus), while those with Kinetoplastea (Trypanosoma) were found in 9% of snakes (Python regius, Corallus caninus) and 25 % of lizards (K. fischeri, Acanthosaura capra, G. gecko). Nematoda including filarial larvae parasitized in 10% of lizards (Agama agama, Agama mwanzae, K. fischeri, Fu. pardalis, Physignathus cocincinus). Light microscopy mostly allowed diagnosis of the parasites' genus, while species identification was not possible because of limited morphological characteristics available for parasitic developmental stages. The investigation revealed a high percentage of imported reptiles being carriers of parasites while possible vectors and pathogenicity are largely unknown so far. The spreading of haemoparasites thus represents an incalculable risk for pet reptiles, native herpetofauna and even human beings.

A comparison of multiple methods for estimating parasitemia of hemogregarine hemoparasites (apicomplexa: adeleorina) and its application for studying infection in natural populations

Identifying factors influencing infection patterns among hosts is critical for our understanding of the evolution and impact of parasitism in natural populations. However, the correct estimation of infection parameters depends on the performance of detection and quantification methods. In this study, we designed a quantitative PCR (qPCR) assay targeting the 18 S rRNA gene to estimate prevalence and intensity of Hepatozoon infection and compared its performance with microscopy and PCR. Using qPCR, we also compared various protocols that differ in the biological source and the extraction methods. Our results show that the qPCR approach on DNA extracted from blood samples, regardless of the extraction protocol, provided the most sensitive estimates of Hepatozoon infection parameters; while allowed us to differentiate between mixed infections of Adeleorinid (Hepatozoon) and Eimeriorinid (Schellackia and Lankesterella), based on the analysis of melting curves. We also show that tissue and saline methods can be used as low-cost alternatives in parasitological studies. The next step was to test our qPCR assay in a biological context, and for this purpose we investigated infection patterns between two sympatric lacertid species, which are naturally infected with apicomplexan hemoparasites, such as the genera Schellackia (Eimeriorina) and Hepatozoon (Adeleorina). From a biological standpoint, we found a positive correlation between Hepatozoon intensity of infection and host body size within each host species, being significantly higher in males, and higher in the smaller sized host species. These variations can be associated with a number of host intrinsic factors, like hormonal and immunological traits, that require further investigation. Our findings are relevant as they pinpoint the importance of accounting for methodological issues to better estimate infection in parasitological studies, and illustrate how between-host factors can influence parasite distributions in sympatric natural populations.

Sprint speed is related to blood parasites, but not to ectoparasites, in an insular population of lacertid lizards

Parasites are able to negatively affect the locomotor performance of their hosts, and consequently, their biological fitness. In this study, we examine the relationship between parasitism and burst speed in an insular population of Lilford’s Wall Lizard (Podarcis lilfordi (Günther, 1874)). Podarcis lilfordi is normally infected with haemogregarine blood parasites and mites in our study location, Aire Island (Balearic Islands, Spain). Unlike the results from other studies on lizards, we found a significant negative correlation between intensity of infection by haemogregarines and burst speed. Body condition is also significantly related to burst speed. Thus, lizards with a lower blood parasite load and better body condition show a faster sprint speed. Intensity of infection by haemoparasites shows a lack of correlation with both body condition and mite load. Our results are compared with those from other lizard species living in different habitats. We discuss the influence of insular environmental conditions on locomotor performances, such as low predation pressure, lack of competitors, and high lizard densities.

Negative correlation between nuptial throat colour and blood parasite load in male European green lizards supports the Hamilton-Zuk hypothesis

During female mate choice, conspicuous male sexual signals are used to infer male quality and choose the best sire for the offspring. The theory of parasite-mediated sexual selection (Hamilton-Zuk hypothesis) presumes that parasite infection can influence the elaboration of sexual signals: resistant individuals can invest more energy into signal expression and thus advertise their individual quality through signal intensity. By preferring these males, females can provide resistance genes for their offspring. Previous research showed that nuptial throat colour of male European green lizard, Lacerta viridis, plays a role in both inter- and intrasexual selections as a condition-dependent multiple signalling system. The aim of this study was to test the predictions of the Hamilton-Zuk hypothesis on male European green lizards. By blood sampling 30 adult males during the reproductive season, we found members of the Haemogregarinidae family in all but one individual (prevalence = 96%). The infection intensity showed strong negative correlation with the throat and belly colour brightness in line with the predictions of the Hamilton-Zuk hypothesis. In addition, we found other correlations between infection intensity and other fitness-related traits, suggesting that parasite load has a remarkable effect on individual fitness. This study shows that throat patch colour of the European green lizards not only is a multiple signalling system but also possibly acts as an honest sexual signal of health state in accordance with the Hamilton-Zuk hypothesis.

Developmental stages of Hepatozoon seurati (Laveran and Pettit 1911) comb. nov., a parasite of the corned viper Cerastes cerastes and the mosquito Culex pipiens from Egypt

Developmental stages of Hepatozoon seurati (Laveran and Pettit 1911) comb. nov. are described from the tissues of the corned viper Cerastes cerastes, and from the vector Culex pipiens. The parasite described in the present study is firstly recorded as Haemogregarina seurati (Laveran and Pettit 1911) in the same host. After demonstration of the sporogonous development in the mosquito vector (C. pipiens) which showed all characteristics of the genus Hepatozoon (large oocysts containing many sporocysts producing numerous sporozoites), the parasite should be transferred into the genus Hepatozoon. The infected erythrocytes measured 20 ± 0.95 × 7.3 ± 0.85 μm; while uninfected cells measured 13.3 ± 1.04 × 7.5 ± 0.16 μm. Hypertrophy and faintly stained cytoplasm are mostly occurred in infected erythrocytes. Blood stages of the parasite were found exclusively in the erythrocytes in two forms: (1) small trophozoites (10.0 ± 0.52 × 3.0 ± 0.4 μm) and (2) long (mature) sausage-shaped (16.5 ± 1.5 × 3.5 ± 0.4 μm). Merogony occurred in the endothelial cells of the blood capillaries of lung, liver, and spleen. Mature meronts was 27.6 ± 0.7 × 17.5 ± 0.5 μm in diameter and contained 20-35 merozoites (averaged in 26). These merozoites measured 16.5 ± 1.5 × 3.5 ± 0.4 μm. Syzygy and gamogony occurred in the mosquito myxocoel till the 5th day post-infection (p.i.) while sporogony took place after 15 days p.i. On the third day p.i., a large spherical macrogamete of 29.0 ± 0.8 × 20.5 ± 0.6 μm containing a distinct nucleus in association with a single microgamete were observed. The microgamete was pyriform measured 8 ± 02 μm in length. It had a prominent nucleus and a long flagellum of at least 20.4 ± 1.3 μm in length. Fertilization occurred on the 3rd to the 4th days p.i. and the formed zygote developed into an oocyst in which repeated mitotic divisions with centripetal invaginations occurred producing sporoblasts. After sporulation, each sporoblast termed as sporocyst, and contained 18 banana-shaped sporozoites measured 14.0 ± 1.6 × 3.2 ± 0.6 μm. Experimental transmission was successful by intraperitoneal inoculation of the infective stages (sporozoites) to uninfected vipers and led to the appearance of blood stages after 5-6 weeks.

Molecular survey and microscopic examination of Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina) in lacertid lizards from the western Mediterranean

The genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina) is composed of intracellular haemogregarine parasites that are widely distributed among all tetrapod groups. The present study combines microscopic and molecular data on haemogregarine parasites from lizards in the western Mediterranean. We screened tissue samples and examined blood smears for the presence of species of Hepatozoon from four lizards, namely Algyroides marchi Valverde, endemic to Southeast Spain, Podarcis bocagei Seoane from Spain and Portugal, P hispanica Steindachner from Spain, and P lilfordi Günther from Cabrera, Balearic Islands (Spain). Our results show that prevalence and intensity of Hepatozoon parasites vary between and within lizard species from different regions. Algyroides marchi and P bocagei from Spain had the lowest values, whereas P hispanica had the highest. Phylogeny based on 18S rRNA gene sequences indicates that most of the new Hepatozoon sequences are part of a clade exclusive from North African and Iberian lizards, except for a single P bocagei isolate that is found related to another clade including isolates from other reptile host species and rodents. Interestingly, isolates from Algyroides form a distinct monophyletic subgroup, which could be a signal of strict host-specificity within this host genus.

Molecular survey of Apicomplexa in Podarcis wall lizards detects Hepatozoon, Sarcocystis, and Eimeria species

The occurrence of apicomplexan parasites in Podarcis sp. wall lizards from the Iberian Peninsula and Balearic islands was studied by amplification and sequencing of the 18S rRNA gene. Species from 3 genera, Hepatozoon , Sarcocystis , and Eimeria , were found. The phylogenetic analysis of the 18S rRNA gene provides unexpected insights into the evolutionary history of these parasites. All Hepatozoon spp. specimens were recovered as part of a clade already identified in lizards from North Africa. The Sarcocystis species, detected in Podarcis lilfordi from Cabrera Island in the Balearic Islands, appears related to Sarcocystis gallotiae , known only from endemic Gallotia sp. lizards from the Canary Islands. Based on the lack of snake predators on this island, this parasite presumably presents an atypical transmission cycle that uses the same host species as both intermediate and final host through cannibalism, like S. gallotiae . Eimeria sp. is reported for the first time from Podarcis spp. lizards. This study shows the power of detecting multiple different apicomplexan parasites through screening of tail tissue samples and blood drops that are often collected in reptiles for other purposes.

The use of a lacertid lizard as a model for reptile ecotoxicology studies: part 2--biomarkers of exposure and toxicity among pesticide exposed lizards

As part of a wider study examining the impacts of corn pesticides on lacertid lizards in north-western Portugal, we examined various physiological, biochemical, and histological biomarkers of exposure and effect among field populations of Podarcis bocagei. Biomarkers included body condition index, standard metabolic rate, locomotor performance, parasitization, glutathione oxidative pathways and related enzyme activity, lipid peroxidation and liver and testis histology. Few of the various biomarkers investigated provided statistically significant evidence of toxic effect. However, using a weight of evidence approach, we conclude that pesticides are affecting lizards living in the vicinity of pesticide exposed corn agriculture sites. Lizards from these locations present a profile of animals under metabolic stress with reduced condition indices, increased standard metabolic rate, lower incidence of hepatocyte vacuolation, altered iron metabolism, increased activation of GSH oxidation pathways, and even increased prevalence of hemoparasites.

HEMOPARASITAS EM JACARÉ AÇU E JACARÉ TINGA CAPTURADOS NA APA MEANDROS DO RIO ARAGUAIA

RESUMO As infecções são comuns tanto em populações silvestres como nas de cativeiro e a ocorrência de doenças está entre as maiores ameaças à diversidade biológica que podem resultar da atividade humana. A maioria das espécies de vida livre enfrenta problemas que aceleram a sua trajetória em direção a uma possível extinção. Haja vista a importância da pesquisa de parasitas em animais silvestres como uma ferramenta para o estudo sanitário de uma população e da qualidade do ambiente, objetivou-se investigar a presença e frequência de hemoparasitas em jacaré açu (Melanosuchus niger) e jacaré tinga (Caiman crocodilus) de vida livre, na Área de Proteção Ambiental Meandros do Rio Araguaia, Goiás, Brasil. Foram avaliados esfregaços sanguíneos de 65 espécimes, 26 M. niger e 39 C. crocodilus, corados com Wright. As coletas ocorreram no período de outubro de 2006 a junho de 2007. Os eritrócitos foram analisados em 20 campos por lâmina. Verificou-se a presença de hemoparasitas intraeritrocitários em 46 (70,76%) dos animais analisados, os quais foram reconhecidos como pertencentes ao gênero Coccidia e da família Haemogregarinidae, revelando um alto índice de hemoparasitose em crocodilianos desta região.

Developmental stages of Hepatozoon hemprichii sp. nov. infecting the skink Scincus hemprichii and the tick Hyalomma impeltatum from Saudi Arabia

The life cycle of Hepatozoon hemprichi n. sp. is described; the vertebrate host is Scincus hemprichii and it is vectored by Hyalomma impeltatum. Erythrocytic stages of 18 ± 1.8 × 4 ± 0.8 µm developed in the hemocoel of ticks to sporozoites within 16-18 days. Schizogony occurred in the liver parenchyma and the endothelial cells of blood capillaries in lung and spleen. Mature schizonts measuring 27 ± 3.11 × 20.13 ± 3.0 µm produced 28 merozoites (on average). The merozoites were 13 ± 1.21 × 1.21 ± 0.72 µm with nuclei 5 ± 0.65 × 2.1 ± 0.51 µm. Syzygy and differentiation of gamonts took place in tick's hemocoel up to the third day post-infection (PI). The microgamont (16 ± 0.31 × 18 ± 0.42 µm) produced 4, uniflagellated microgametes at 4-5 days PI. The microgamete measured 15.2 ± 0.31 µm while the flagellum was always at least 26 µm. The macrogamete was very large in size (31 ± 3.11 µm) with a central nucleus. After fertilization, (5-6 days PI) zygotes developed into oocysts (55 ± 3.41 × 52 ± 4.11 µm) in which repeated mitotic divisions with centripetal invaginations occurred; each contained 18 banana-shaped sporozoites, 13.61 ± 0.8 × 1.2 ± 0.31 µm in size. Experimental transmission was successfully carried out by oral administration or by intra-peritoneal inoculation of the infective stages (sporozoites) to uninfected skinks and led to the appearance of blood stages after 5 wk and 4 wk, respectively.