The development of Hepatozoon sipedon sp. nov. (Apicomplexa: Adeleina: Hepatozoidae) in its natural host, the Northern water snake (Nerodia sipedon sipedon), in the culicine vectors Culex pipiens and C. territans, and in an intermediate host, the Northern leopard frog (Rana pipiens)

Mercury bioaccumulation and Hepatozoon spp. infections in two syntopic watersnakes in South Carolina

Mercury (Hg) is a ubiquitous environmental contaminant known to bioaccumulate in biota and biomagnify in food webs. Parasites occur in nearly every ecosystem and often interact in complex ways with other stressors that their hosts experience. Hepatozoon spp. are intraerythrocytic parasites common in snakes. The Florida green watersnake (Nerodia floridana) and the banded watersnake (Nerodia fasciata) occur syntopically in certain aquatic habitats in the Southeastern United States. The purpose of this study was to investigate relationships among total mercury (THg) concentrations, body size, species, habitat type and prevalence and parasitemia of Hepatozoon spp. infections in snakes. In the present study, we sampled N. floridana and N. fasciata from former nuclear cooling reservoirs and isolated wetlands of the Savannah River Site in South Carolina. We used snake tail clips to quantify THg and collected blood samples for hemoparasite counts. Our results indicate a significant, positive relationship between THg and snake body size in N. floridana and N. fasciata in both habitats. Average THg was significantly higher for N. fasciata compared to N. floridana in bays (0.22 ± 0.02 and 0.08 ± 0.006 mg/kg, respectively; p < 0.01), but not in reservoirs (0.17 ± 0.02 and 0.17 ± 0.03 mg/kg, respectively; p = 0.29). Sex did not appear to be related to THg concentration or Hepatozoon spp. infections in either species. We found no association between Hg and Hepatozoon spp. prevalence or parasitemia; however, our results suggest that species and habitat type play a role in susceptibility to Hepatozoon spp. infection.

Diversity of Hepatozoon species in wild mammals and ticks in Europe

BACKGROUND

Hepatozoon spp. are tick-borne parasites causing subclinical to clinical disease in wild and domestic animals. Aim of this study was to determine Hepatozoon prevalence and species distribution among wild mammals and ticks in Europe.

METHODS

Samples of wild mammals and ticks, originating from Austria, Bosnia and Herzegovina, Croatia, Belgium and the Netherlands, were tested with PCR to amplify a ~ 670-bp fragment of the small subunit ribosomal RNA gene.

RESULTS

Of the 2801 mammal samples that were used for this study, 370 (13.2%) tested positive. Hepatozoon canis was detected in samples of 178 animals (3 Artiodactyla, 173 Carnivora, 1 Eulipotyphia, 1 Lagomorpha), H. martis in 125 (3 Artiodactyla, 122 Carnivora), H. sciuri in 13 (all Rodentia), Hepatozoon sp. in 47 (among which Hepatozoon sp. Vole isolate, all Rodentia) and H. ayorgbor in 4 (all Rodentia). Regarding origin, 2.9% (6/208) tested positive from Austria, 2.8% (1/36) from Bosnia and Herzegovina, 14.6% (173/1186) from Croatia and 13.9% (190/1371) from Belgium/the Netherlands. Of the 754 ticks collected, 0.0% (0/35) Hyalomma sp., 16.0% (4/25) Dermacentor spp., 0.0% (0/23) Haemaphysalis spp., 5.3% (24/50) Ixodes and 1.4% (3/221) Rhipicephalus spp. tested positive for Hepatozoon (4.2%; 32/754), most often H. canis (n = 22).

CONCLUSIONS

Hepatozoon canis is most present in mammals (especially in Carnivora such as gray wolves and golden jackals) and ticks, followed by H. martis, which was found merely in stone martens and pine martens. None of the rodent-associated Hepatozoon spp. were detected in the ticks, suggesting the possible implication of other arthropod species or non-vectorial routes in the transmission cycle of the hemoprotozoans in rodents. Our findings of H. canis in ticks other than R. sanguineus add to the observation that other ticks are also involved in the life cycle of Hepatozoon. Now that presence of Hepatozoon has been demonstrated in red foxes, gray wolves, mustelids and rodents from the Netherlands and/or Belgium, veterinary clinicians should be aware of the possibility of spill-over to domestic animals, such as dogs.

A 50-year-old redescription: molecular and morphometric characterization of Hepatozoon carinicauda Pessôa and Cavalheiro, 1969 in the brown-banded water snake Helicops angulatus (Linnaeus, 1758)

The combined use of molecular and microscopic techniques has become an increasingly common and efficient practice for the taxonomic and evolutionary understanding of single-celled parasites such as haemogregarines. Based on this integrative approach, we characterized Hepatozoon found in Helicops angulatus snakes from the Eastern Amazonia, Brazil. The gamonts observed caused cell hypertrophy and were extremely elongated and, in some cases, piriform (mean dimensions: 25.3 ± 1.9 × 8.6 ± 1.3 μm). These morphological features correspond to Hepatozoon carinicauda, described 50 years ago in the snake Helicops carinicaudus in the southeast region of Brazil. Phylogenetic and genetic divergence analyses, performed with the sequence obtained from the amplification of a 590 bp fragment of the 18S rRNA gene, revealed that Hepatozoon in He. angulatus differed from the other lineages retrieved from GenBank, and was clustered singly in both the phylogenetic tree and the haplotype network. The integration of these data allowed the identification of H. carinicauda in a new aquatic host, and increased the knowledge of its geographical distribution. Therefore, the present study included the first redescription of a Hepatozoon species in a snake from the Brazilian Amazon.

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.

Molecular and morphological description of the first Hepatozoon (Apicomplexa: Hepatozoidae) species infecting a neotropical turtle, with an approach to its phylogenetic relationships

Haemogregarines (Adeleorina) have a high prevalence in turtles. Nevertheless, there is only one Hepatozoon species described that infects Testudines so far; it is Hepatozoon fitzsimonsi which infects the African tortoise Kinixys belliana. Colombia harbours a great diversity of chelonians; however, most of them are threatened. It is important to identify and characterize chelonian haemoparasite infections to improve the clinical assessments, treatments and the conservation and reintroduction programs of these animals. To evaluate such infections for the Colombian wood turtle Rhinoclemmys melanosterna, we analysed blood from 70 individuals. By using the morphological characteristics of blood stages as well as molecular information (18S rRNA sequences), here we report a new Hepatozoon species that represents the first report of a hepatozoid species infecting a semi-aquatic continental turtle in the world. Although the isolated lineage clusters within the phylogenetic clades that have morphological species of parasites already determined, their low nodal support makes their position within each group inconclusive. It is important to identify new molecular markers to improve parasite species identification. In-depth research on blood parasites infecting turtles is essential for increasing knowledge that could assess this potential unknown threat, to inform the conservation of turtles and for increasing the state of knowledge on parasites.

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.

New insights on the diversity of Brazilian anuran blood parasites: With the description of three new species of Hepatozoon (Apicomplexa: Hepatozoidae) from Leptodactylidae anurans

The Amphibia are considered the most threatened vertebrate class globally, yet in Brazil they are also one of the more diverse and species rich groups. Although, in recent years there has been strong focus on amphibian related research, their parasites have not received the same attention. In Brazil, only a single species of Hepatozoon, namely H. leptodactyli (Lesage, 1908) Pessoa, 1970, has been described from anuran hosts. The present study aimed to describe three new species of Hepatozoon parasitising Leptodactylus labyrinthicus and Leptodactylus latrans from Mato Grosso State, Brazil. From 66 anurans screened for haemogregarines, four belonging to the Leptodactylidae were found positive for species of Hepatozoon. Based on the morphological analysis of peripheral blood gamonts and spleen and liver tissue meronts, three different morphotypes of Hepatozoon spp. were identified. Morphotype 1 (M1) and morphotype 2 (M2) in L. labyrinthicus and morphotype 3 (M3) in L. latrans. Molecular data based on partial 18S rDNA sequences revealed an interspecific divergence, between the species ranging from 0.43% to 1.16%. Phylogenetic analysis recovered isolates from the present study monophyletic with other isolates from Brazilian reptile and anuran hosts, sister to a clade comprising species isolated from African, North American and European reptile and anuran host species. Thus, using morphological and molecular analysis three new species infecting Brazilian Leptodactylidae anurans were identified and described. This study increases the knowledge of Brazilian anurans blood parasites and demonstrates the importance of using integrative approaches for diagnosis of hemoparasites.

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Diversity and phylogenetic relationship of haemogregarines from Brazilian anurans.

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Description of a three new species of Hepatozoon from Brazilian anurans.

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First report of species of Hepatozoon descriptions using both morphological and molecular approaches from Brazilian anurans.

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Merogonic data of Hepatozoon spp. infection on Brazilian anurans.

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.

Morphometric and molecular characterisation of Hepatozoon bashtari n. sp. in painted saw-scaled viper, Echis coloratus (Ophidia, Viperidae)

Hepatozoon species are the most widely known haemogregarines infecting a wide range of vertebrates, although predominately snakes. Herein, Hepatozoon bashtari n. sp., originally infecting the painted saw-scaled viper, Echis coloratus, in Saudi Arabia is described using both morphological features and molecular data from 18S rDNA sequences. The overall prevalence of infection was 60% (9/15) with parasitaemia ranging from 52 to 60%. Gamonts were entirely intraerythrocytic and were observed to cause considerable hypertrophy within the host cell. The mean size of mature gamonts was 15.4 × 3.3 μm. Merogonic stages were confined to the lung endothelial cells with monomorphic meronts. The average size of mature meronts was 32 × 12 μm and they were estimated to produce 13-16 merozoites each. The phylogenetic tree generated from SSU rDNA sequences revealed that Hepatozoon bashtari sp. n. clusters with the vast majority of other Hepatozoon species infecting snakes, lizards and geckos in various regions of the world, which would appear to support the hypothesis of prey-predator transmission of the genus Hepatozoon. Through a combination of morphological comparison with closely related Hepatozoon spp. and 18S rRNA gene sequence analysis, it is possible to confirm Hepatozoon bashtari sp. n. as a new species.

Linking behavioral thermoregulation, boldness, and individual state in male Carpetan rock lizards

Mechanisms affecting consistent interindividual behavioral variation (i.e., animal personality) are of wide scientific interest. In poikilotherms, ambient temperature is one of the most important environmental factors with a direct link to a variety of fitness-related traits. Recent empirical evidence suggests that individual differences in boldness are linked to behavioral thermoregulation strategy in heliothermic species, as individuals are regularly exposed to predators during basking. Here, we tested for links between behavioral thermoregulation strategy, boldness, and individual state in adult males of the high-mountain Carpetan rock lizard (Iberolacerta cyreni). Principal component analysis revealed the following latent links in our data: (i) a positive relationship of activity with relative limb length and color brightness (PC1, 23% variation explained), (ii) a negative relationship of thermoregulatory precision with parasite load and risk-taking (PC2, 20.98% variation explained), and (iii) a negative relationship between preferred body temperature and relative limb length (PC3, 19.23% variation explained). We conclude that differences in boldness and behavioral thermoregulatory strategy could be explained by both stable and labile state variables. The moderate link between behavioral thermoregulatory strategy and risk-taking personality in our system is plausibly the result of differences in reproductive state of individuals or variation in ecological conditions during the breeding season.

Molecular detection of Apicomplexan hemoparasites in anurans from Brazil

Amphibians are among the most threatened vertebrate groups in the world, and the main causes include climate change, habitat destruction, and emerging diseases. Herein, we investigated the occurrence and characterized molecularly Apicomplexa in anurans from southeastern Brazil. Forty individuals from seven anuran species were sampled in São Paulo state. In the molecular analyses, one Leptodactylus latrans and one Rhinella diptycha were positive in PCR assays for species of Hepatozoon. Two L. latrans were also positive for coccidian infections (Lankesterella sp. and an unidentified coccidian species). Phylogenetic analysis based on 18S rDNA clustered the sequences detected in anurans from the present study with Hepatozoon spp. detected in reptiles and other anurans from Brazil, albeit they were separate from Hepatozoon haplotypes detected in frogs from Africa and North America. Our study showed, for the first time, the molecular detection of Lankesterella sp. and another coccidian in L. latrans. Additionally, co-infection by different species of Hepatozoon haplotypes and an unidentified coccidian in anurans from Brazil was documented.

Phylogenetic analysis of Hepatozoon spp. (Apicomplexa: Hepatozoidae) infecting Philodryas patagoniensis (Serpentes: Dipsadidae) in Uruguay

The purpose of this study was to perform a phylogenetic analysis of Hepatozoon spp. infecting Philodryas patagoniensis in Uruguay. Twenty-five road-killed specimens of P. patagoniensis from ten departments were obtained. Samples of blood and/or heart tissue were taken. Polymerase chain reaction (PCR) assay was carried out amplifying a specific target region of the 18S rRNA gene of Hepatozoon spp. Eighteen out of twenty-five samples were positive to Hepatozoon spp., which gave an overall prevalence of 72%. Phylogenetic analyses with the obtained sequences were carried out to determine the relationship with closely related species found in the region. The results revealed that samples were split into two clades with a high bootstrap support. Clade I was formed with Hepatozoon spp. sequences obtained in this study from P. patagoniensis, Hepatozoon cuestensis from Crotalus durissus terrificus and Hepatozoon musa from Philodryas nattereri, and Hepatozoon spp. retrieved from Cerdocyon thous, Hemidactylus mabouia, and Phyllopezus pollicaris from Brazil, respectively. Clade II was grouped with Hepatozoon cevapii and Hepatozoon massardii, both species described for C. d. terrificus from Brazil. This is the first report of Hepatozoon spp. in snakes from Uruguay.

First detection and genetic identification of Hepatozoon canis in Rhipicephalus sanguineus sensu lato ticks collected from dogs of Taiwan

We determined the prevalence of infection and genetic identity of Hepatozoon spp. harbored by Rhipicephalus sanguineus sensu lato ticks in Taiwan. A total of 1082 ticks were collected from dogs and DNA extraction was performed from individual tick specimens. Hepatozoon infection was detected by performing a nested-PCR assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. The genetic identity of detected Hepatozoon was identified by gene sequencing and phylogenetic analysis. Hepatozoon infection was detected in nymphs, males and females of R. sanguineus s. l. ticks with an infection rate of 20.8%, 22.8% and 29.4%, respectively. Sequence and phylogenetic analysis revealed that these Hepatozoon spp. of Taiwan were genetically affiliated to the same clade within the genospecies of H. canis and can be discriminated from other genospecies of H. americanum and H. felis. Intraspecies analysis based on the genetic distance (GD) values indicates a lower level (GD < 0.005) genetic divergence within the same genospecies of H. canis detected in Taiwan, Brazil and Spain. Interspecies analysis also reveals a higher heterogeneity of Taiwan strains distinguished from other genospecies of H. felis (GD > 0.040) and H. americanum (GD > 0.056). This study provides the first molecular evidence of H. canis detected and identified in various stages of R. sanguineus s. l. ticks in Taiwan. Detection of H. canis in unfed male ticks may imply the possible mechanism of transstadial survival in R. sanguineus s. l. ticks. Further investigations on Hepatozoon spp. harbored by various vector ticks in Taiwan may illustrate the epidemiological significance of this parasite.

Hepatozoon milleri sp. nov. (Adeleorina: Hepatozoidae) in Akodon montensis (Rodentia: Cricetidae: Sigmodontinae) from southeastern Brazil

Members of the genus Hepatozoon (Miller, 1908) are blood parasites found in a wide range of host species, including wild rodents; however, information about the life cycle, distribution and Hepatozoon species diversity infecting these mammals are lacking. We studied the parasite stages and DNA sequences of Hepatozoon sp. of 11 naturally infected Akodon montensis. Thin blood smears, tissue samples and whole blood were obtained for morphology, morphometry and molecular analyses. Seven of the 11 rodents had gamonts on the blood smears. Biological and morphological features of the parasite such as tissue tropism, gamonts and meronts size and morphology, as well as the DNA sequence comparison and phylogenetic analysis, indicated that the Hepatozoon sp. detected in this study is distinct from those species previously reported in small rodents. Herein, we propose a new species, named Hepatozoon milleri sp. nov. This is the first description of a new Hepatozoon species from wild small rodents in Brazil, based on morphological and molecular characteristics.

Pathogenic and endosymbiont apicomplexans in Ctenocephalides felis (Siphonaptera: Pulicidae) from cats in Jerusalem, Israel

This study was conducted to determine the prevalence of pathogenic and endosymbiont apicomplexans in the cat flea, Ctenocephalides felis (Bouché) infesting 185 stray cats in Jerusalem, Israel using PCR assay and sequencing approach. Two pathogens, Hepatozoon felis and Babesia vogeli and an endosymbiont Steinina ctenocephali were detected in 1.9%, 0.2% and 5.8% of 685 C. felis evaluated respectively. There was a significant association (p < 0.05) between the prevalence of H. felis and the sex of cats hosting the fleas as well as the season of sampling but not for age or health status of the cats or sex of the fleas tested. Prevalence of S. ctenocephali was significantly (p < 0.001) associated with season, being higher in the warm season. This report represents the first molecular detection of S. ctenocephali in C. felis. Further studies to determine the potential role of C. felis in the epidemiology of H. felis and B. vogeli are warranted.

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.

Hepatozoon silvestris sp. nov.: morphological and molecular characterization of a new species of Hepatozoon (Adeleorina: Hepatozoidae) from the European wild cat (Felis silvestris silvestris)

Based on morphological and genetic characteristics, we describe a new species of Hepatozoon in the European wild cat (Felis silvestris silvestris), herein named Hepatozoon silvestris sp. nov. The study also provides the first data on the occurrence of H. felis in this wild felid. Hepatozoon meronts were observed in multiple cross-sections of different organs of four (44%) cats. Additionally, extracellular forms, resembling mature gamonts of Hepatozoon, were found in the spleen and myocardium of two cats. Furthermore, tissues of six animals (67%) were positive by PCR. Hepatozoon felis was identified infecting one cat (11%), whereas the 18S rRNA sequences of the remaining five cats (56%) were identical, but distinct from the sequences of H. felis. Phylogenetic analyses revealed that those sequences form a highly supported clade distant from other Hepatozoon spp. Future studies should include domestic cats from the areas where the wild cats positive for H. silvestris sp. nov. were found, in order to investigate their potential role to serve as intermediate hosts of this newly described species. Identification of its definitive host(s) and experimental transmission studies are required for elucidating the full life cycle of this parasite and the possible alternative routes of its transmission.

Hepatozoon spp. infections in wild rodents in an area of endemic canine hepatozoonosis in southeastern Brazil

Hepatozoon canis is a tick-borne parasite that occurs worldwide. In rural areas of Brazil, H. canis vectors remain unknown, which has led to speculation about alternative routes of transmission. Small rodents can play a role in the transmission (via predation) of Hepatozoon americanum, which led us to question whether predation might be an alternative mode of transmission for H. canis. Thus, this study investigated whether Hepatozoon spp. are present in wild small rodents in forest fragments that surround rural areas in Botucatu County, São Paulo, Brazil, where canine hepatozoonosis is endemic. The study included blood samples from 158 dogs, which were screened by microscopy and molecular analysis. Blood samples and tissues from 67 rodents were obtained for histopathology and molecular detection. The prevalence of H. canis was high (66.45%) in dogs from rural areas of Botucatu, São Paulo, Brazil. The molecular analysis showed that wild rodent species in Brazil were infected with Hepatozoon spp. other than H. canis. Therefore, although the hypothesis that sylvatic rodents act as reservoirs for H. canis was not supported, the presence of monozoic cysts in the rodents suggests that, in addition to intermediate hosts, wild small rodents in Brazil might act as paratenic hosts of Hepatozoon spp. because they harbor infective stages for intermediate host predators.

Characterization of Hepatozoon spp. in Leptodactylus chaquensis and Leptodactylus podicipinus from two regions of the Pantanal, state of Mato Grosso do Sul, Brazil

Hepatozoon sp. are parasites that commonly infect frogs and arthropod vectors. This species has variability in the morphological and morphometric characteristics. Due to these variations, the naming of the species is thus impaired and only by visualizing the sporogonic cycle in vector and by molecular studies this problem can be solved. Recently, the use of molecular genetics has helped the species denomination. In this work, we collected 145 frogs (68 Leptodactylus chaquensis and 77 Leptodactylus podicipinus) in different sampling sites, where were found 18 (26.47%) L. chaquensis and 24 (31.17%) L. podicipinus parasitized; besides of gamonts, schizogonic forms were also seen in animals organs. The positivity difference between the collection sites for both frog species was not significant (p = 0.958). Comparing gamonts found in each species of anuran, we observed differences in morphology. The comparison in the molecular level for L. podicipinus was not possible due to small amount of blood obtained, just L. chaquensis had their parasites DNA sequenced. The amplified and sequenced samples, named HEP1 to HEP10, are presented in the phylogenetic tree as a different branch from other haemogregarines described on other hosts. Therefore, we have seen that, although the morphology and morphometry of the collected parasites at each site showed differences, the sequencing of these samples revealed identical species of Hepatozoon, and different compared to those from GenBank, thereby demonstrating that the species of Hepatozoon in L. chaquensis observed in this study probably represent a new species.

Hepatozoon species (Adeleorina: Hepatozoidae) of African bufonids, with morphological description and molecular diagnosis of Hepatozoon ixoxo sp. nov. parasitising three Amietophrynus species (Anura: Bufonidae)

Background

Haemogregarines comprise a large group of apicomplexan blood parasites. In 1996 all anuran haemogregarines still in the genus Haemogregarina Danilewsky, 1885 were reassigned to the genus Hepatozoon Miller, 1908. Most (11/15, 73%) African anuran Hepatozoon species have been recorded from the family Bufonidae, however, all these are recorded from only two host species, Amietophrynus mauritanicus (Schlegel, 1841) and Amietophrynus regularis (Reuss, 1833) from Northern and central Africa. To the authors’ knowledge the only description of an anuran haemogregarine from South Africa is Hepatozoon theileri (Laveran, 1905), parasitising Amietia quecketti (Boulenger, 1895).

Methods

Thin blood smears for morphometrics and whole blood for molecular work, were collected from 32 Amietophrynus garmani (Meek, 1897), 12 Amietophrynus gutturalis (Power, 1927), and nine Amietophrynus maculatus (Hallowell, 1854), in Ndumo Game Reserve and Kwa Nyamazane Conservancy, KwaZulu-Natal, South Africa. Smears were Giemsa-stained, screened for haemogregarines, parasite stages measured, compared to each other and to other described African bufonid haemogregarines. Parasite 18S rDNA was amplified using two apicomplexan-specific primer sets, HepF300/HepR900 and 4558/2733. Resulting sequences of the haemogregarine isolates from the three Amietophrynus species were compared with each other and to comparative haemogregarine sequences selected from GenBank.

Results

Morphological characteristics of parasite stages, in particular characteristically capped mature gamont stages, and molecular findings, supported all three haemogregarine isolates from all three Amietophrynus species to be the same, a species of Hepatozoon, and furthermore different morphologically from other previously recorded bufonid Hepatozoon species. The haemogregarine fell within a clade comprising other anuran Hepatozoon species and furthermore, within a monophyletic sub-clade along with H. theileri and are described as Hepatozoon ixoxo sp. nov.

Conclusions

This is the first morphological and molecular account of Hepatozoon species within the family Bufonidae from South Africa, a study hoped to encourage the redescription and molecular analysis of those Hepatozoon species described in the past from Amietophrynus species, as well as to promote the use of both morphological and molecular characteristics in Hepatozoon species descriptions. This will aid in comprehensive Hepatozoon descriptions, which along with the use of phylogenetic analysis will give a better indication of these parasites possible vectors and life cycle dynamics.

Phylogenetic relationship of Hepatozoon blood parasites found in snakes from Africa, America and Asia

The blood parasites from the genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleida: Hepatozoidae) represent the most common intracellular protozoan parasites found in snakes. In the present study, we examined 209 individuals of snakes, from different zoogeographical regions (Africa, America, Asia and Europe), for the occurrence of blood parasites using both molecular and microscopic examination methods, and assess phylogenetic relationships of all Hepatozoon parasites from snakes for the first time. In total, 178 blood smears obtained from 209 individuals, representing 40 species, were examined, from which Hepatozoon unicellular parasites were found in 26 samples (14·6% prevalence). Out of 180 samples tested by molecular method polymerase chain reaction (PCR), the presence of parasites was observed in 21 individuals (prevalence 11·6%): 14 snakes from Africa belonging to six genera (Dendroaspis, Dispholidus, Mehelya, Naja, Philothamnus and Python), five snakes from Asia from the genus Morelia and two snakes from America, from two genera (Coluber and Corallus). The intensity of infection varied from one to 1433 infected cells per 10 000 erythrocytes. Results of phylogenetic analyses (Bayesian and Maximum Likelihood) revealed the existence of five haplotypes divided into four main lineages. The present data also indicate neither geographical pattern of studied Hepatozoon sp., nor congruency in the host association.

Fecundity reduction in the second gonotrophic cycle of Culex pipiens infected with the apicomplexan blood parasite, Hepatozoon sipedon

Fecundity reduction is a well-recognized phenomenon of parasite infection in insects. Reduced production of eggs might increase longevity of a host and release nutrients to both host and parasite that would otherwise be used for oogenesis. The objective of this study was to assess effects on fecundity caused by Hepatozoon sipedon, an apicomplexan blood parasite of snakes, in its invertebrate host, the mosquito Culex pipiens. In the first gonotrophic cycle, the mean number of eggs laid by mosquitoes infected with H. sipedon did not differ significantly from those laid by uninfected mosquitoes. However, in the second gonotrophic cycle infected mosquitoes laid significantly fewer eggs than did uninfected mosquitoes, and fecundity was reduced by 100% in mosquitoes with parasite burdens of more than 60 oocysts. There was a significant negative correlation between parasite burden, or the number of oocysts, and the number of eggs produced in the second gonotrophic cycle. Significantly fewer viable larvae hatched from eggs laid by infected compared to uninfected mosquitoes in the second gonotrophic cycle. These data indicate that fecundity reduction occurs in this system, although the physiological mechanisms driving this phenotype are not yet known.

Are fish paratenic natural hosts of the caiman haemoparasite Hepatozoon caimani?

The susceptibility of two fish and four mosquito species to the Caiman yacare haemoparasite Hepatozoon caimani was experimentally investigated. Mosquitoes belonging to four species (Aedes fluviatilis, Aedes albopictus, Aedes aegypti and Culex quinquefasciatus) were blood-fed on two naturally infected C. yacare from the Central-West Region of Brazil that exhibited distinct levels of parasitaemia: caimans A (11.05%) and B (1.25%). None of the engorged A. fluviatilis, A. albopictus or A. aegypti mosquitoes fed on caiman A survived for the duration of the sporogonic cycle; the great majority of the engorged mosquitoes died within 48 h of the blood meal. All A. aegypti fed on caiman B were negative, whereas 91.3% of dissected C. quinquefasciatus fed on the same caiman contained oocysts. Characid fish-Metynnis sp. and Astyanax sp.-were individually fed with C. quinquefasciatus females previously engorged (21-23 days) on caiman B. No parasite was found in the Astyanax fish. By contrast, 100% of the Metynnis fish depicted numerous cysts harbouring cystozoites identical to those of H. caimani, even more than 8 months after the ingestion of the infected mosquitoes. The cysts were located near the veins of the liver and, in some cases, close to the tunica intima of these vessels. No inflammatory reaction was observed. Gametocytes were observed in the blood smears of juvenile caimans that had ingested infected fish 9-12 weeks earlier. The potential role of fish as paratenic vertebrate hosts of H. caimani in nature is discussed.

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.

Redescription of Hepatozoon felis (Apicomplexa: Hepatozoidae) based on phylogenetic analysis, tissue and blood form morphology, and possible transplacental transmission

Background

A Hepatozoon parasite was initially reported from a cat in India in 1908 and named Leucocytozoon felis domestici. Although domestic feline hepatozoonosis has since been recorded from Europe, Africa, Asia and America, its description, classification and pathogenesis have remained vague and the distinction between different species of Hepatozoon infecting domestic and wild carnivores has been unclear. The aim of this study was to carry out a survey on domestic feline hepatozoonosis and characterize it morphologically and genetically.

Methods

Hepatozoon sp. DNA was amplified by PCR from the blood of 55 of 152 (36%) surveyed cats in Israel and from all blood samples of an additional 19 cats detected as parasitemic by microscopy during routine hematologic examinations. Hepatozoon sp. forms were also characterized from tissues of naturally infected cats.

Results

DNA sequencing determined that all cats were infected with Hepatozoon felis except for two infected by Hepatozoon canis. A significant association (p = 0.00001) was found between outdoor access and H. felis infection. H. felis meronts containing merozoites were characterized morphologically from skeletal muscles, myocardium and lungs of H. felis PCR-positive cat tissues and development from early to mature meront was described. Distinctly-shaped gamonts were observed and measured from the blood of these H. felis infected cats. Two fetuses from H. felis PCR-positive queens were positive by PCR from fetal tissue including the lung and amniotic fluid, suggesting possible transplacental transmission. Genetic analysis indicated that H. felis DNA sequences from Israeli cats clustered together with the H. felis Spain 1 and Spain 2 sequences. These cat H. felis sequences clustered separately from the feline H. canis sequences, which grouped with Israeli and foreign dog H. canis sequences. H. felis clustered distinctly from Hepatozoon spp. of other mammals. Feline hepatozoonosis caused by H. felis is mostly sub-clinical as a high proportion of the population is infected with no apparent overt clinical manifestations.

Conclusions

This study aimed to integrate new histopathologic, hematologic, clinical, epidemiological and genetic findings on feline hepatozoonosis and promote the understanding of this infection. The results indicate that feline infection is primarily caused by a morphologically and genetically distinct species, H. felis, which has predilection to infecting muscular tissues, and is highly prevalent in the cat population studied. The lack of previous comprehensively integrated data merits the redescription of this parasite elucidating its parasitological characteristics.

Influence of Hepatozoon parasites on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens

Hepatozoon species are heteroxenous parasites that commonly infect the blood of vertebrates and various organs of arthropods. Despite their ubiquity, little is known about how these parasites affect host phenotype, including whether or not these parasites induce changes in hosts to increase transmission success. The objectives of this research were to investigate influences of the frog blood parasite Hepatozoon clamatae and the snake blood parasite Hepatozoon sipedon on host-seeking and host-choice behaviour of the mosquitoes Culex territans and Culex pipiens, respectively. During development of H. sipedon in C. pipiens, significantly fewer infected mosquitoes fed on uninfected snakes compared to uninfected mosquitoes. When H. sipedon was mature in C. pipiens, the number of infected and uninfected C. pipiens that fed on snakes was not significantly different. Higher numbers of mosquitoes fed on naturally infected snakes and frogs compared to laboratory-reared, uninfected control animals. However, experiments using only laboratory-raised frogs revealed that infection did not significantly affect host choice by C. territans. Behaviour of C. pipiens in the presence of H. sipedon may increase transmission success of the parasite and provide the first evidence of phenotypic changes in the invertebrate host of Hepatozoon parasites.

Four additional hepatozoon species (Apicomplexa: Hepatozoidae) from north Florida ratsnakes, genus Pantherophis

Records from a colubrid host are reported for Hepatozoon horridus, described originally from a viperid snake. Hepatozoon horridus in Pantherophis guttatus (Colubridae) has gamonts 14-18.0 by 4.0-5.5 microm, with length by width (LW) 60-99 microm2, and L/W ratio 2.5-3.9. Spherical to elongate, usually ovoid oocysts with L/W ratio 1.0-3.7 contain 16-160 spherical to usually ovoid sporocysts 15-31 by 14-26 microm, with L/W ratio 1.0-1.4, that contain 5-24 sporozoites. Two additional Hepatozoon species are described from ratsnakes in north Florida. Hepatozoon quadrivittata n. sp. from Pantherophis obsoletus quadrivittatus has gamonts 12-17 by 4-6 microm, LW 56-102 microm2, and L/W ratio 2.6-3.8. Nearly spherical oocysts with L/W 1.0-1.1 contain 5-227 spherical to slightly ovoid sporocysts 20-48 by 19-45 microm, with L/W ratio 1.0-1.4, that contain 13-48 sporozoites. Hepatozoon spiloides n. sp. from Pantherophis obsoletus spiloides forms gamonts 12-15 by 4-5 microm with LW 48-75 microm2 and L/W ratio 2.6-3.5. Occasionally rounded but usually elongate oocysts, with L/W ratio 1.0-2.7, contain 5-21 spherical to elongate sporocysts 28-43 by 18-35 microm, L/W ratio 2.5-3.9. In the distinctive Hepatozoon sp. present in Pantherophis obsoletus spiloides, gamonts are 13-17 by 5-10 microm, with LW 75-140 microm2 and L/W ratio 1.4-3.0. Infected erythrocytes are always distorted and enlarged on average 2.5 times the size of uninfected cells, with nuclei enlarged by one-third and broadly elongated. Gamonts often stained deep blue, and cytoplasm of erythrocytes infected with mature gamonts was always dehemoglobinized. Sporogony could not be obtained in three feedings by hundreds of Aedes aegypti, which usually died within the first 24-48 hr.

Hepatozoon spp. (Apicomplexa: Hepatozoidae) infection and selected hematological values of the neotropical rattlesnake, Crotalus durissus collilineatus (Linnaeus, 1758) (Serpentes: Viperidae), from Brazil

This study aims to establish the hematological values of Crotalus durissus collilineatus snakes captured in Brazil as well as to verify the effects of hematozoan infection on these snakes. Eighty-three blood samples were drawn from C. d. collilineatus specimens for analysis. The sample set was composed of 30 males and 30 females, recently caught from the wild, and 11 males and 12 females bred in captivity. Blood samples were used to determine red blood cell counts, white blood cell counts, thrombocyte counts, hematocrit values, hemoglobin concentration, and total plasma protein. Blood smears were used to diagnose Hepatozoon spp. infection and to calculate the parasitic load in the sample as well as the percentage of immature red cells. Results obtained for the wild-caught animals, with and without parasites, were compared among themselves and with the values obtained for the captive-bred animals. Hematological values for C. durissus were established. Wild-caught snakes had an infection rate of 38.3%, while no Hepatozoon sp. infection was detected in the captive-bred animals. The snakes which were not infected by the Hepatozoon sp. exhibited average weight, length, and weight-length ratios higher than those of the infected animals. An increase in immature red cells was noted in the Hepatozoon-infected snakes.

Anurans as paratenic hosts in the transmission of Hepatozoon caimani to caimans Caiman yacare and Caiman latirostris

Prevalence of Hepatozoon caimani has been reported in 76% of caimans Caiman yacare from the Pantanal region. Culex (Melanoconion) spp. mosquitoes were recently identified as natural vectors of this parasite. However, culicids are not typically eaten by crocodilians, suggesting that the main transmission route is through ingestion of insectivorous vertebrates, such as anurans. The susceptibility of wild frogs Leptodactylus chaquensis, Leptodactylus podicipinus and Scinax nasicus to infection by H. caimani was verified. Wild-caught anurans were force fed with sporulated oocysts from laboratory-bred Culex (Melanoconion) mosquitoes. Frogs were killed 30 days postinfection, and their internal organs were fed to caimans C. yacare and Caiman latirostris. Cystozoites were identified in fresh liver impression smears of L. chaquensis. C. yacare fed on anuran organ presented gametocytes in peripheral blood circulation between 74 and 80 days postinoculation (dpi). Gametocytes were also verified in C. latirostris fed on the internal organs of L. podicipinus and S. nasicus between 60-70 and 69-75 dpi, respectively. Since frogs used in experiment are sympatric with C. yacare and C. latirostris and may occur in the diet of these caimans, the results suggest these amphibians are paratenic hosts in the natural transmission cycle of H. caimani in Pantanal.

Perspectives on canine and feline hepatozoonosis

Two species of Hepatozoon are currently known to infect dogs and cause distinct diseases. Hepatozoon canis prevalent in Africa, Asia, southern Europe, South America and recently shown to be present also in the USA causes infection mainly of hemolymphoid organs, whereas Hepatozoon americanum prevalent in the southeastern USA causes myositis and severe lameness. H. americanum is transmitted by ingestion of the Gulf Coast tick Amblyomma maculatum and also by predation on infected prey. H. canis is transmitted by Rhipicephalus sanguineus, in South America also by Amblyomma ovale, and has also been shown to be transmitted transplacentally. Hepatozoonosis of domestic cats has been described mostly from the same areas where canine infection is present and the exact identity of the species which infect cats, their pathogenicity and vectors have not been elucidated. The diagnosis of hepatozoonosis is made by observation of gamonts in blood smears, histopathology, PCR or serology. The main treatment for H. canis is with imidocarb dipropionate whereas H. americanum infection is treated with an initial combination of trimethoprim-sulfadiazine, pyrimethamine and clindamycin followed by maintenance with decoquinate. Treatment for both diseases has not been reported to facilitate complete parasite elimination and new effective drugs are needed for the management of these infections. Prevention of hepatozoonosis should be based on avoidance of oral ingestion of infected tick vectors and infected prey.

Rodents as intermediate hosts of Hepatozoon ayorgbor (Apicomplexa: Adeleina: Hepatozoidae) from the African ball python, Python regius?

Two experimental trials were performed to elucidate the role of rodents in the life cycle of Hepatozoon species using snakes as intermediate hosts. In one trial, two ball pythons, Python regius Shaw, 1802 were force fed livers of laboratory mice previously inoculated with sporocysts of Hepatozoon ayorgbor Sloboda, Kamler, Bulantová, Votýpka et Modrý, 2007. Transmission was successful in these experimentally infected snakes as evidenced by the appearance of intraerythrocytic gamonts, which persisted until the end of trial, 12 months after inoculation. Developmental stages of haemogregarines were not observed in histological sections from mice. In another experimental trial, a presence of haemogregarine DNA in mice inoculated with H. ayorgbor was demonstrated by PCR in the liver, lungs and spleen.

A new species of Hepatozoon (Apicomplexa: Adeleorina) from Python regius (Serpentes: Pythonidae) and its experimental transmission by a mosquito vector

Hepatozoon ayorgbor n. sp. is described from specimens of Python regius imported from Ghana. Gametocytes were found in the peripheral blood of 43 of 55 snakes examined. Localization of gametocytes was mainly inside the erythrocytes; free gametocytes were found in 15 (34.9%) positive specimens. Infections of laboratory-reared Culex quinquefasciatus feeding on infected snakes, as well as experimental infection of juvenile Python regius by ingestion of infected mosquitoes, were performed to complete the life cycle. Similarly, transmission to different snake species (Boa constrictor and Lamprophis fuliginosus) and lizards (Lepidodactylus lugubris) was performed to assess the host specificity. Isolates were compared with Hepatozoon species from sub-Saharan reptiles and described as a new species based on the morphology, phylogenetic analysis, and a complete life cycle.

LIFE CYCLE OF HEPATOZOON CANIS (APICOMPLEXA: ADELEORINA: HEPATOZOIDAE) IN THE TICK RHIPICEPHALUS SANGUINEUS AND DOMESTIC DOG (CANIS FAMILIARIS)

The life cycle of the apicomplexan protozoon Hepatozoon canis in its natural hosts Rhipicephalus sanguineus (tick) and Canis familiaris (domestic dog) was studied in an experimental infection. Tick nymphs were fed on a naturally infected dog, or they were infected by percutaneous injection of blood. Dogs were inoculated by ingestion of adult ticks containing mature oocysts. Gamonts were in syzygy 24 hr after percutaneous injection of ticks. Early oocysts were detected 96 hr after nymph repletion, and mature oocysts in adult ticks were infective to dogs 40 days postmolt. Merogony was detected in dog bone marrow from 13 days postinoculation (PI) and included meronts containing 20-30 micromerozoites, and a second type with 2-4 macromerozoites. Monozoic cysts were observed in the spleen in conjunction with merogony. Gamontogony with infection of leukocytes by micromerozoites occurred from 26 days PI, and gamont parasitemia, which completed the life cycle, was detected 28 days PI. The length of the life cycle from nymphal attachment to parasitemia in dogs was 81 days. Increased body temperatures were evident from 16 to 27 days PI and paralleled the time of intensive bone marrow merogony. Skeletal pain and recumbency were manifested in 2 dogs. This study further elucidates the life cycle of H. canis and provides a sequential morphologic description of H. canis merogony, gamontogony, and sporogony.

Do parasites matter? Assessing the fitness consequences of haemogregarine infection in snakes

Although much research in evolutionary ecology is based upon the premise that high levels of parasitism impair the host's functioning, the assumed link between parasitism and fitness has been assessed for relatively few kinds of animals. At our study site in tropical Australia, keelback snakes ( Tropidonophis mairii (Gray, 1841), Colubridae) are heavily infected with haemogregarine blood parasites: 90% of snakes that we tested carried the parasite, with the proportion of erythrocytes containing haemogregarines averaging 15% and ranging up to a remarkable 64%. Prevalence increased with snake body size, but intensity decreased with age. Unlike lizards studied previously, the snakes did not respond to haemogregarine infection by releasing immature erythrocytes into the circulation. In striking contrast to results from a recent study on a sympatric snake species, we did not find any empirical links between parasite numbers and several measures of host fitness (body condition, growth rate, feeding rate, antipredator behaviour, locomotor performance, reproductive status, reproductive output, and recapture rate). The association between this parasite and its host thus appears to be surprisingly benign, suggesting that host–parasite interactions sometimes may have only trivial consequences for host fitness in natural populations. Plausibly, host–parasite coevolution weakens or eliminates fitness costs of parasitism.

Prevalence and intensity of haemogregarine blood parasites and their mite vectors in the common wall lizard, Podarcis muralis

We describe the general field population biology of haemogregarines and mites in the wall lizard, Podarcis muralis, examining the factors that determine the prevalence and intensity of infection. The intensity of infection by haemogregarines in females was slightly lower in summer than in spring, whereas males maintained similar levels of intensity among all the seasons, probably due to immunosuppressive effects of testosterone. This is also supported because the prevalence and the infection intensity by mites were higher in males than in females. Parasite load was higher in lizards with better body condition, which could be reflecting the mortality of infected lizards with poor condition.

Prevalence and intensity of haemogregarinid blood parasites in a population of the Iberian rock lizard, Lacerta monticola

The study of the effect of parasites on their host populations is essential for understanding their role in host population dynamics and ecology. We describe the general field population biology of haemogregarines in the Iberian rock lizard, Lacerta monticola, examining the factors that determine the prevalence and intensity of infection. Prevalence and infection intensity were higher in adults than in juvenile lizards. The prevalence rate was higher in larger lizards, probably because they were also older and had been more often in contact with parasites during their lifetime. During the mating season, the intensity of parasite infection was greater in males than in females, probably due to immunosuppressive effects of testosterone. The parasite load had a negative effect on the body condition during the reproductive season. The results suggest that the interactions between parasites and hosts are not stable in this lizard population.

Monozoic cysts of Hepatozoon canis

Small monozoic cysts found in the spleen of dogs infected with Hepatozoon canis are described from naturally and experimentally infected dogs. These forms of H. canis resemble cysts formed by other Hepatozoon species that infect frogs, lizards, and grey squirrels as intermediate hosts. The H. canis cyst stage differs in size and morphology from the large cysts of H. americanum, the second Hepatozoon species known to infect dogs.