DESCRIPTION OF THE FIRST KLOSSIA SPECIES (APICOMPLEXA: EUCOCCIDIORIDA: ADELEORINA: ADELEIDAE) INFECTING A PULMONATE LAND SNAIL, TRIODOPSIS HOPETONENSIS (MOLLUSCA: POLYGYRIDAE), IN NORTH AMERICA.

Snails identified as Triodopsis hopetonensis were collected (n = 18) from the University of Arkansas-Fayetteville campus in December 2018. Additional snails were collected in April 2019 (n = 9) and in September 2019 (n = 9). Kidney tissues were examined using light microscopy, and polysporocystic oocysts were observed. Sporulated oocysts (n = 2) measured 78 ± 3.4 µm × 76 ± 2.9 µm with an irregular oocyst residuum and contained an estimated 44-55 tetrazoic sporocysts. The sporocysts (n = 10) measured 13 ± 0.5 µm × 11 ± 1.5 µm with an indistinct, irregularly placed, sporocyst residuum and usually contained 4 sporozoites, although an octozoic variant was observed. DNA was extracted from the snail kidney tissues and used as a template for polymerase chain reaction (PCR). PCR was used to determine the infection status of the snails; 13 of 36 (36%) specimens were found to be infected with a new Klossia species, and only 3 (8%) of these infections were detected using light microscopy. The complete nuclear 18S ribosomal DNA (1,800 bp) and mitochondrial genomes (6,775 bp) were generated, and they differentiated this parasite from the type species Klossia helicina and support the description of this new Klossia species, Klossia razorbacki n. sp. This is the first Klossia species to be described from any North American snail.

Hepatic Coccidiosis in Triportheus angulatus Spix & Agassiz, 1829 (Characiformes: Triportheidae), a Tropical Fish from the Eastern Brazilian Amazon, with the Description of a New Species of Calyptospora (Apicomplexa: Calyptosporidae).

Hepatic infection involving a parasite of the family Calyptosporidae was recorded in characiform fish from the Tocantins river in the Brazilian Amazon region. In the present study, an integrated comparative analysis of morphological characteristics, histological and structural traits, and the sequence of a partial fragment of the SSUrRNA gene provides support for the identification of a new calyptosporid species, found parasitising the hepatic tissue of the fish Triportheus angulatus, collected from the Tocantins River. This new species was named Calyptospora gonzaguensis n. sp. and had ovoid oocysts with a diameter of 19.6 ± 1.4 µm and four peripheral sporocysts, 9.2 ± 0.6 µm long and 3.9 ± 0.2 µm wide, enveloped individually in fine adhesive membrane, composed of an ellipsoid body and posterior extension, with a mean length of 2.2 ± 0.4 µm.

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.

Morphological and Molecular Characterization of Aggregata spp. Frenzel 1885 (Apicomplexa: Aggregatidae) in Octopus vulgaris Cuvier 1797 (Mollusca: Cephalopoda) from Central Mediterranean.

Coccidian parasites of the genus Aggregata are known to parasitize cephalopods as definitive hosts, however one of the genus members, A. octopiana, has shown an unresolved phylogeny within the same definitive host, the common octopus (Octopus vulgaris). Our study represents a large-scale investigation aimed at characterizing morphological traits and phylogeny of A. octopiana isolated from O. vulgaris inhabiting three distinct geographic areas of the central Mediterranean: The Adriatic, Ionian and Tyrrhenian Seas. The morphology of sporogonic stages of the parasite in octopus tissues was assessed by light and electron microscopy; molecular characterization has been carried out using the 18S rRNA locus. Our results support the hypothesis that two morphologically and genetically different A. octopiana infect O. vulgaris in the investigated areas of the Mediterranean Sea. Additional nuclear and mitochondrial markers for Aggregata should provide further information and better resolution of its phylogeny.

Hepatozoon caimani Carini, 1909 (Adeleina: Hepatozoidae) in wild population of Caiman yacare Daudin, 1801 (Crocodylia: Alligatoridae), Pantanal, Brazil.

Previous studies showed infections of Hepatozoon caimani in wild populations of caimans in wide regions from Brazil; some of those demonstrated that trophic chain are linked to natural infections through paratenic hosts or by the direct ingestion of vectors. These studies life cycle of H. caimani contributed inestimably to the knowledge of transmission routes, yet but lack enhancement tools for better detail of parasite. This study reports the forms in the blood and tissues, and also partial molecular characterization of the H. caimani following part of the 18S rRNA region. In the southern Pantanal, there were sampling 39 adult caimans (Caiman yacare), where 31 (79.5%) were parasitized by H. caimani. Free gametocytes had an average intensity of 19.6% and intraerythrocytic forms 7.42%, in the blood smears. In stained smears of the liver and lungs of naturally infected caimans which were examined, monozoic and dizoic cysts were found in these tissues, generally next to the vessels. In the histopathology, meronts were observed in the wall of vessels from liver and kidney ducts. Blood samples were forwarded to PCR process and produced amplicons with about 600 and 900 bp, respectively, for the primers HEPF300/HEP900 and HEMO1/HEMO2. This was the first report of molecular confirmation of Hepatozoon in populations of naturally infected caimans of morphological detail of the gametocytes in scanning electron microscopy and histology of merogony in livers and kidneys of C. yacare.

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

To date, only two haemogregarine parasite species have been described from South African anurans: Hepatozoon ixoxo, infecting toads of the genus Sclerophrys (syn. Amietophrynus); and Hepatozoon theileri, parasitising the common river frog, Amietia quecketti. Both species have been characterised using limited morphology, and molecular data from PCR amplified fragments of the 18S rRNA gene. However, no ultrastructural work has been performed thus far. The aim of this study was to add descriptive information on the two species by studying their ultrastructural morphology. Mature gamont stages, common in the peripheral blood of infected frogs, were examined by transmission electron microscopy. Results indicate that H. ixoxo and H. theileri share typical apicomplexan characteristics, but differ markedly in their external cellular structure. Hepatozoon ixoxo is an encapsulated parasite presenting a prominent cap at the truncate pole, and shows no visible modifications to the host cell membrane. In comparison, H. theileri does not present a capsule or cap, and produces marked morphological changes to its host cell. Scanning electron microscopy was performed to further examine the cytopathological effects of H. theileri, and results revealed small, knob-like protrusions on the erythrocyte surface, as well as notable distortion of the overall shape of the host cell.

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.

Description of a New Haemogregarine, Haemogregarina sundarbanensis n. sp. (Apicomplexa: Haemogregarinidae) from Mud Turtle of Sundarban Regions, West Bengal, India.

OBJECTIVE: The aim of this study was to provide a description of a new haemogregarine, Haemogregarina sundarbanensis n. sp., from mud turtles collected from Sundarban regions, West Bengal, India. METHODS: The turtles were collected from fish markets near Canning, South 24-Parganas District, West Bengal. Thin blood films were prepared using the blood drawn from the head and feet. The blood films were then air-dried, fixed in absolute methanol, and stained with Giemsa. RESULTS: The erythrocytic stages could be differentiated into small and large forms. The young gamonts measured 7.896×3.469 µm, microgamonts measured 8.876×4.425 µm, and macrogamonts measured 8.919×4.272 µm. The cytoplasm of the macrogamonts was stained deep blue with Giemsa, and many metachromatic granules are found uniformly distributed. The oval or rounded nucleus was central in position and stained deep red with Giemsa stain, whereas in microgamonts, the nucleus was not at all compact but with a few dispersed chromatin granules. CONCLUSION: The prevalence of infection was found to be 33.3% (5/15). The infected erythrocytes reveal shape alteration, marginal and atrophic nucleus, and were larger than non-parasitized erythrocytes. The cytoplasm of the infected erythrocytes stained darker than that of the uninfected erythrocytes.

First molecular characterization of a Hepatozoon species (Apicomplexa: Hepatozoidae) infecting birds and description of a new species infecting storm petrels (Aves: Hydrobatidae).

During a survey of blood parasites in a population of Leach's and black storm petrels ( Oceanodroma leucorhoa and Oceanodroma melania) in Mexico, infection by a Hepatozoon species in erythrocytes of several birds was noted. Here we describe the species as Hepatozoon peircei sp. nov. Some species of Hepatozoon described from birds have been identified as lankesterellids when DNA molecular analyses were conducted. However, a sequence of 1,774 bp of the parasite found infecting storm petrels in this study clearly show the parasite is a species of the genus Hepatozoon. This is the first Hepatozoon species infecting birds to be characterized at the molecular level and the first found infecting erythrocytes and not leucocytes.

Molecular and morphological description of a Hepatozoon species in reptiles and their ticks in the Northern Territory, Australia.

Ticks, representing 3 species of Amblyomma, were collected from the water python (Liasis fuscus) and 3 additional reptile species in the Northern Territory, Australia, and tested for the presence of Hepatozoon sp., the most common blood parasites of snakes. In addition, blood smears were collected from 5 reptiles, including the water python, and examined for the presence of the parasite. Hepatozoon sp. DNA was detected in all tick and reptile species, with 57.7% of tick samples (n = 187) and 35.6% of blood smears (n=35) showing evidence of infection. Phylogenetic analysis of the 18S rRNA gene demonstrated that half of the sequences obtained from positive tick samples matched closest with a Hepatozoon species previously identified in the water python population. The remaining sequences were found to be more closely related to mammalian and amphibian Hepatozoon species. This study confirms that species of Amblyomma harbor DNA of the same Hepatozoon species detected in the water pythons. The detection of an additional genotype suggests the ticks may be exposed to 2 Hepatozoon species, providing further opportunity to study multiple host-vector-parasite relationships.

Hepatozoon species of the timber rattlesnake in northern Florida: description of a new species, evidence of salivary gland oocysts, and a natural cross-familial transmission of an Hepatozoon species.

Two species of Hepatozoon, i.e., H. sauritus and H. horridus n. sp., were present in 1 of 8 timber rattlesnakes, Crotalus horridus. The narrow gamonts of H. sauritus are 15.0-19.0 x 3.5-5.0 microm, with LW 58-86 microm2 and L/W 3.2-4.7, with a narrow, rounded anterior end. The spherical to slightly ovoid oocysts produce ovoid to elongate sporocysts, 21-43 x 12-24 microm, L/W 1.20-2.7, containing on average 22.1 (10-34) sporozoites. This is the first report of a natural cross-familial transfer of a Hepatozoon species. Gamonts of H. horridus n. sp. are 13.0-17.0 x 4.0-6.0 microm, with LW 63-102 microm2 and L/W 2.6-4.0, and have broadly rounded ends. The gamont cytoplasm is vacuolated. The spherical to ovoid oocysts form spherical to elongate sporocysts 14-45 x 11-25 microm, L/W 1.0-2.3, producing an average of 13.0 (8-21) sporozoites. The salivary gland in 1 of 5 mosquitoes dissected contained 1 mature oocyst.

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.

Molecular characterization of the 18S rDNA gene of an avian Hepatozoon reveals that it is closely related to Lankesterella.

As a part of intensive study of blood parasite infections in a population of the passerine bird blue tit (Cyanistes caeruleus, Paridae), we detected a parasite species that, based on its morphological similarity, was tentatively identified as Hepatozoon parus, the only species of this parasite genus described from birds of this family. However, morphological measurements show that H. parus is slightly larger than the parasite detected in our population. A molecular characterization of the parasite species was conducted by amplification of the 18S rDNA gene, using primers that were reported previously to amplify in Hepatozoon sp. of water pythons. Additional primers were developed based on the new sequence obtained. The 1,484-bp fragment amplified reveals that the parasite from our bird population is more closely related to Lankesterella minima than to Hepatozoon species from other vertebrates according to analysis using the BLAST comparison method (93% identity). In addition, phylogenetic analyses using parsimony and Kimura procedures unequivocally related the parasite species detected by PCR with L. minima. The bootstrap values obtained were 97% and 100%, respectively. These results imply that this parasite is a species of a lankesterellid instead of Hepatozoon.

Two additional Hepatozoon species (Apicomplexa: Hepatozoidae) from the southern black racer, Coluber constrictor priapus (Serpentes: Colubridae), in northern Florida.

Hepatozoon priapus n. sp. from Coluber constrictor priapus has robust gamonts with broadly rounded ends, 18.0 x 4.2 microm (17.0-20.0 x 3.5-6.0), with LW 76.4 microm2 (59-105) and L/W 4.31 (2.9-5.4). The nucleus is always present in second quarter of gamont, seldom extend into first quarter but often into third quarter, 6.0 x 3.0 (5.0-7.0 x 2.5-4.0), with LW 17.9 (13.7-21.0). Erythrocyte cytoplasm is always thin, appearing dehemoglobinized, with infected cells always distorted. Infected erythrocytes are much longer and wider than uninfected cells, with longer nuclei. Oocysts are spherical to ovoid, 92.5 x 86.0 (55-123 x 47-115) and L/W 1.08 (1.0-1.3), contain 14.0 (6-31) sporocysts. Sporocysts, which are also spherical to ovoid, 26.3 x 23.3 (19-50 x 16-38), LW 641.2 (320-1,500) and L/W 1.13 (1.0-2.2), contain 12.6 (5-18) sporozoites. Hepatozoon confusus n. sp., also from C. constrictor priapus, has slender gamonts with rounded ends, 15.6 x 4.1 (14.0-17.0 x 3.5-5.0), with LW 64.3 (52-80) and L/W 3.82 (2.8-4.4). The nucleus is always present in second quarter of gamont, commonly extending into first and third quarters, 5.0 x 2.7 (2.5-4.4 x 4.0-6.0), with LW 13.5 (11.0-16.5). Erythrocyte cytoplasm is sometimes thin, appearing partially dehemoglobinized, with infected cells usually distorted. Infected erythrocytes are longer than uninfected cells but similar in width, with erythrocyte nuclei longer. Oocysts are spherical to ovoid, 115.5 x 108.9 (52-278 x 50-278), with L/W 1.06 (1.0-1.2), and contain 25.0 (7-111) sporocysts. Sporocysts are spherical to ovoid, 27.6 x 25.2 (21-38 x 20-33), LW 701.3 (420-1,125) and L/W 1.09 (1.0-1.4), containing 20.2 (12-32) sporozoites.

Hepatozoon polytopis n. sp. parasitic in two genera and species of colubrid snakes in southern Florida.

Hepatozoon polytopis, described from Coluber constrictor priapus from Palm Beach County, Florida, has short, usually broad gamonts 12.8 x 4.6 microm (10.0-15.0 x 3.5-6.0), with LW 58.5 microm2 (42-84) and L/W 2.84 (1.8-3.7). Nuclei commonly extend into first quarter of gamont (45%), are always present in second quarter, and seldom in third quarter (11%), with dimensions 4.5 x 3.4 (3.0-6.0 x 2.5-4.5) and LW 15.1 (10.0-24.0). Spherical to ovoid oocysts, 122.1 x 104.9 (62-240 x 57-190), with L/W 1.17 (1.0-1.9), contain 31.3 (3-103) sporocysts. Spherical to ovoid sporocysts, 38.0 x 33.9 (28-73 x 25-58), with LW 1,325.1 (756-4,168) and L/W 1.12 (1.0-1.4), contain 42.9 (22-64) sporozoites. Thamnophis sauritus sackenii from Palm Beach County is infected also by H. polytopis, as indicated from similar gamont dimensions and verified by isolation of an identical haplotype of the 18S ribosomal RNA gene from both host species.

Hepatozoon sauritus: a polytopic hemogregarine of three genera and four species of snakes in north Florida, with specific identity verified from genome analysis.

Hemogregarines from Thamnophis s. sirtalis, Coluber constrictor priapus, Elaphe obsoleta quadrivittata, and E. g. guttara in northern Florida appeared to be conspecific on the basis of similar gamonts from all the hosts and sporogonic stages obtained from 3 hosts. The resemblance of gamonts to those of Hepatozoon sauritus, described from T. sauritus sackenii in southern Florida, justified comparison of DNA isolates from the type infection of H. sauritus with samples from each of the northern Florida hosts and with a morphologically distinct species, H. sirtalis, from northern Florida. A nucleotide sequence (530 bp) alignment of the 18S ribosomal RNA gene revealed 2 hemogregarine haplotypes that varied at 15 sites (p distance = 2.8%), which included 10 transitions and 5 transversions. Two well-supported clusters (100% bootstrap support) were revealed by a neighbor-joining tree topology. One cluster included the type infection of H. sauritus and all 4 of the other samples from the northern Florida hosts, with samples of H. sirtalis comprising a second cluster. Hepatozoon sauritus, therefore, is a polytopic species in contrast to the 8 other Hepatozoon species thus far described from snakes in Florida, each of which appears to parasitize a single host species.

Phylogenetic relationships of Hepatozoon (Haemogregarina) boigae, Hepatozoon sp., Haemogregarina clelandi and Haemoproteus chelodina from Australian reptiles to other Apicomplexa based on cladistic analyses of ultrastructural and life-cycle characters.

The phylogeny of representative haemozoan species of the phylum Apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. The analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: Haemogregarina clelandi from the Brisbane River tortoise (Emydura signata), Hepatozoon sp. from the slaty grey snake (Stegonotus cucullatus), Hepatozoon (Haemogregarina) boigae from the brown tree snake (Boiga irregularis), and Haemoproteus chelodina from the saw-shelled tortoise (Elseya latisternum). There was no apparent correlation between parasite phylogeny and that of their vertebrate hosts, but there appeared to be some relationship between parasites and their intermediate hosts, suggestive of parasite/vector co-evolution.

Ultrastructure of Hepatozoon boigae (Mackerras, 1961) nov. comb. from brown tree snakes, Boiga irregularis, from northern Australia.

Intraerythrocytic bodies identified as haemogregarine gamonts were found in 29% of 97 brown tree snakes (Boiga irregularis) examined during a haematological survey of reptiles in Australasia during 1994-1998. The morphological characteristics of the parasites were consistent with those of Haemogregarina boigae Mackerras, 1961, although the gamonts were slightly larger and lacked red caps but contained distinctive polar grey capsules. Gamonts did not distend host cells but laterally displaced their nuclei. They were contained within parasitophorous vacuoles and possessed typical apicomplexan organelles, including a conoid, polar rings, rhoptries and micronemes. Schizonts producing up to 30 merozoites were detected in endothelial cells of the lungs of 11 snakes. The absence of erythrocytic schizogony suggests the parasites belong to the genus Hepatozoon. Electron microscopy also revealed the presence of curious encapsulated organisms in degenerating erythrocytes. These stages did not possess apical complex organelles and were surrounded by thick walls containing circumferential junctions and interposed strips reminiscent of oocyst sutures.

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.

Erythrocytic and merogonic stages of Hepatozoon ridibundae sp. nov. infecting the Arabian ranid frogs, Rana ridibunda in Saudi Arabia with reflections on the haemogregarine complex.

The prevalence and levels of parasitaemia of haemogregarine infection among Arabian ranid frogs, Rana ridibunda, in Saudi Arabia was studied for the first time. Erythrocytic and merogonic stages of Hepatozoon ridibundae sp. nov. in the intermediate vertebrate host, R. ridibunda were described by light microscopy. The erythrocytic parasites were differentiated into small form (trophozoite) measuring 14.6 +/- 0.3 x 3.8 +/- 0.4 microm and the mature form (gamont) which was banana-shaped with hooked anterior end and blunt broad posterior end and measuring 19.8 +/- 1.8 x 5.2 +/- 0.6 microm. The gamonts of the present parasite induced nuclear fragmentation or segmentation in host erythrocytes. Merogony, of the ectomerogonic type, took place in the liver parenchyma cells. Two meront types were observed. Small meronts (micromeronts) yielded 2-6 (average 4) large merozoites (macromerozoites) measuring 16.6 +/- 0.6 x 6.2 +/- 0.5 microm in size. Large meronts (macromeronts) yielded 18-30 (average 24) elongated merozoites (micromerozoites) measuring 15.2 +/- 0.3 x 3.8 +/- 0.4 microm. A partial systematic revision of the haemogregarine complex was discussed in the view of the diagnostic characteristic features of the 6 recognized haemogregarine genera.