The biology of some intraerythrocytic parasites of fishes, amphibia and reptiles

Unoculubranchiobdella sp. (Hirudinea: Ozobranchidae) as a vector for Haemogregarina spp. in freshwater turtles from Brazil

Species of Haemogregarina are blood parasites known to parasitise vertebrate hosts, including fishes (Haemogregarina sensu lato) and freshwater turtles (Haemogregarina sensu stricto). Their vectors, include gnathiid isopods and leeches, respectively. In turtles, Haemogregarina balli has the best-characterized life cycle in the genus. However, no studies in Brazil have suggested a possible vector for any species of Haemogregarina from freshwater turtles. Therefore, in the present study, we provide insights into a leech vector based on specimens found feeding on two species of freshwater turtles, Podocnemis unifilis and Podocnemis expansa, using morphological and molecular data. In 2017 and 2019, freshwater turtles were collected in Goiás State, Brazil. Hosts were inspected for ectoparasites and leeches were collected from two specimens of P. expansa and nine specimens of P. unifilis. Leeches were subsequently identified as members of the genus Unoculubranchiobdella. Leech histological slides revealed haemogregarine-like structures, similar to post-sporogonic merogony, found near the gills and within the posterior sucker. Molecular analysis of the haemeogregarines resulted in the identification of three species of Haemogregarina: Haemogregarina embaubali, Haemogregarina goianensis, and Haemogregarina brasiliana. Therefore, our findings, based on morphology and DNA data suggest leeches of the genus Unoculubranchiondella as vectors for at least three species of Haemogregarina from Brazilian turtles.

Hemoparasites Do Not Affect Life-History Traits and Cellular Immune Response in Treefrog Hosts Boana cordobae

We provide the first evidence for hemoparasites in the endemic Cordoba treefrog Boana cordobae. We collected 37 adult frogs at 1200 m a.s.l. in the Comechingones Mountains in the Córdoba province (Argentina). Each individual was sexed, then snout-vent length and body mass were recorded, a toe was collected for skeletochronological age determination, and a slide with a blood smear was prepared for hemoparasite screening, before releasing the frogs in situ. A total of 81% (n = 30) of the frogs were infected by hemogregarines and trypanosomes with a high intensity of infections. Dactylosoma was found for the first time in Argentina. Hemoparasites had no significant effect on the leukocyte profile, which we assessed from the May-Grünwald-Giemsa-stained blood smears. The neutrophils/lymphocytes ratio, indicative of stress, was insignificantly higher (0.06) in parasitized frogs than in parasite-free individuals (0.04). Infected frogs were larger than the controls, but this effect vanished when correcting size data for age. Young frogs (first-breeders) dominated the age distribution of parasite-free individuals, suggesting that infection of frogs takes usually place after sexual maturation. Vectors transmitting hemoparasites to B. cordobae remain to be identified. We demonstrate that moderate to high intensities of hemoparasites do not significantly affect the cellular immune response of B. cordobae, or any of the life-history traits studied, nor did they show any external sign of disease.

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.

Hemogregarine Diversity Infecting Brazilian Turtles with a Description of Six New Species of Haemogregarina (Apicomplexa: Adeleorina: Haemogregarinidae)

(1) Background: Hemoparasites of the genus Haemogregarina (Haemogregarinidae) are commonly reported in freshwater turtles. However, in Brazil, only three species have currently been characterised using molecular methods. This study aimed to bring new insights on the diversity of species of Haemogregarina infecting Brazilian freshwater turtles from Mato Grosso and Goiás states using molecular and morphological tools. (2) Methods: In total, 2 mL of blood was collected, with between two to five blood smears prepared, fixed with absolute methanol, and stained with a 10% Giemsa solution. Blood was stored at −20 °C for molecular analysis targeting the 18S rRNA gene. Fragments of the organs (liver, spleen, heart, and kidney) were separated and stained with hematoxylin-eosin. (3) Results: A total of 40 turtles were screened and hemogregarines were observed in 34 (85%) individuals (3 Podocnemis expansa and 31 Podocnemis unifilis). Haemogregarina embaubali and six new species of Haemogregarina were observed and formally described as follows: H. unifila n. sp., H. rubra n. sp., H. goianensis n. sp., H. araguaiensis n. sp., H. tigrina n. sp., and H. brasiliana n. sp. (4) Conclusions: This study contributes to the diversity and knowledge of Brazilian fresh-water turtle blood parasites, using integrative approaches for diagnosing and characterizing hemoparasites, with the identification of six undescribed species.

The Biological, Histopathological, and Parasitic Abundance of Oreochromis niloticus Inhabiting Two Different Freshwater Canals

The current study aimed to assess the impact of metal pollution in water on parasitic abundance, biology, and histopathological characteristics of Oreochromis niloticus in two different freshwater habitats in the Al Sharkia government. The fish were collected from the Mueweis canal area (A) which received industrial wastewater from factories and the San El-Hagar area (B) which received agricultural and domestic wastewater. Parasitic abundance and histopathological changes in the liver and gonads were inspected. The total prevalence of parasitic infection was at the highest percentage in area B correlated with metals present in the water, in addition to severe histopathological damage to the liver and the gonads. The prevalence of parasites for different examined fish ranges from 50% for parasites in the San El-Hagar canal and 4.17% for parasites in the Muwies canal, seasonally. There were positive relationships between Fe or Zn or Mn concentrations with parasite abundance in tilapia fish collected from the San Hagar canal. Several histopathological alterations were detected in the liver and gonads of O. niloticus collected from the two canals located in the Al Sharkia province. It was concluded that the uncontrolled inputs of agricultural and domestic wastes highly altered the O. niloticus health status and the prevalence of the parasites in the investigated two areas.

Diversity of Haemogregarine Parasites Infecting Brazilian Anurans, with a Description of New Species of Dactylosoma (Apicomplexa: Adeleorina: Dactylosomatidae)

PURPOSE

Brazilian anurans are considered the most diverse and species rich around the world. Although in recent years there has been a strong focus on research related to this group of animals, their parasites have not received the same attention. Thus, this study aimed to provide morphological and molecular data on haemogregarines biodiversity infecting Brazilian anurans.

METHODS

During 2020, 116 anurans were collected from four Brazilian States and their blood and fragment of organs were screened for haemogregarine parasites.

RESULTS

From the total, seven (6.03%) animals were found infected with species of Hepatozoon and Dactylosoma. Based on the morphological and molecular analysis, four anurans were found infected with Hepatozoon latrensis. The phylogenetic analysis has shown the isolates from this study grouping with the Brazilian anuran Hepatozoon clade, also with gene similarity ranging from 99.70 to 100% to H. latrensis isolates available on GenBank. Furthermore, three specimens (Trachycephalus typhonius, Leptodactylus latrans, and Rhinella diptycha) were infected with the same species of Dactylosoma (100% genetic similarity), with a genetic similarity of 98.56% to Dactylosoma piperis the only other species described in Brazil. In support of the molecular data, different morphological characters were observed in the blood smears as compared to D. piperis, suggesting that the species of Dactylosoma from the present study infecting three different species of Brazilian anurans is an undescribed species.

CONCLUSION

Thus, this study increases the knowledge of Brazilian anuran blood parasites and demonstrates the importance of using integrative approaches for the diagnosis of haemoparasites.

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

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

Haemosporidian infections in wild populations of Podarcis muralis from the Italian Peninsula

Parasites can significantly influence the ecology, behaviour and physiology of their hosts sometimes with remarkable effects on their survivorship. However, endemic parasites or those not associated with obvious clinical disease have been partly neglected in the past decades comparatively to the most pathogenic ones. Apicomplexa are an important example of blood parasites that have been broadly investigated, although it can be difficult to determine the effects of infections at the population level, especially in widespread species. Such is the case of the common wall lizard (Podarcis muralis). We investigated 61 populations across Italy between 2008 and 2017 and recorded snout–vent length, latitude, date of collection and took blood samples for parasite count. We modelled parasite prevalence and load in a Bayesian framework. Parasites were present in all populations but 1 and in 13 of them all individuals were parasitized. We recorded almost identical responses for probability of infection and parasite load in both sexes, directly proportional to body size and inversely proportional to latitude, with a peak in cooler months. Therefore, haemosporidians can be very common in P. muralis, although their presence can vary significantly. Moreover, such a high prevalence makes it necessary to investigate to what extent haemosporidians affect hosts' survivorship, taking into consideration abiotic and biotic factors such as temperature, hormone levels and immune response.

Hematological and serum biochemical reference intervals of rainbow trout, Oncorhynchus mykiss cultured in Himalayan aquaculture: Morphology, morphometrics and quantification of peripheral blood cells

De novo reference intervals (RIs) for a total of thirty two hematological and serum biochemical attributes were established for rainbow trout (Oncorhynchus mykiss) cultured in Himalayan aquaculture system. For this purpose, long term assessment of hemato-biochemical parameters was carried over a period of one year from March 2019 to February 2020 and a total of 444 blood samples were analysed. Blood examination results were recorded systematically and reference intervals were established, notably for erythrocyte parameters: hematocrit (Hct) 29–40%, hemoglobin 8.32–12.28 g/dL, red blood cell (RBC) count 1.01–2.04 (×10⁶/mm3); leukocyte parameters (x 10³/mm3): total leukocytes 31.32–90.60, neutrophils 4.21–18.85, total lymphocytes 20.55–63.63, small lymphocytes 14.86–46.50, large lymphocytes 6.35–22.34 and monocytes 1.22–7.56; thrombocyte count 23.00–68.00 (×10⁶/mm3). RIs were also established for red blood cell indices, vital serum constituents involved in carbohydrate, protein, lipid and nitrogen metabolism including the less known, diagnostically important, serum enzymes and electrolyte concentrations. Principal component analysis revealed that certain serum components were more efficient at distinguishing between the life stages (juvenile, adult) of fish by explaining about 92.7% of variation in the whole dataset compared to the principal hematological components which explained only about 80% of the variation. Significant (P < 0.05) differences were noted for RBC count, total leukocyte count (TLC), total protein, total cholesterol and uric acid with respect to the sex of fish. Moreover, clearly differentiable morphometric and morphological attributes were also noticed among erythrocytes, leukocytes (lymphocytes, neutrophils and monocytes) and thrombocytes. To our knowledge, the present study is the first of its kind that elucidates blood chemistry of cultured rainbow trout, O. mykiss in accordance to the guidelines framed by the American society of veterinary clinical pathologists (ASVCP). RIs reported here can help monitor the fish health status by improving the use of non-lethal diagnostics in piscine medicine.

Prediction of in-hospital recurrence and false-negative results in patients with COVID-19 by red blood cell values on admission

The clinical characteristics and risk factors of patients with coronavirus disease 2019 (COVID-19) with re-positive or false-negative test results have so far remained to be determined. The present study provides a cross-sectional observational study on 134 hospitalized patients selected from Huoshenshan Hospital (Wuhan, China) using cluster sampling. A total of 68 patients had reduced red blood cell (RBC) counts, 55 a decrease in the hemoglobin concentration (HBC) and 73 a decline in hematocrit (HCT). The false-negative rate of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RNA detection in pharyngeal swab specimens was 18.7%. The absolute lymphocyte count (ALC), RBC, HBC and HCT levels in false-negative patients were significantly higher than those in patients who tested positive for viral nucleic acids. Multivariate logistic regression analysis indicated that RBC [odds ratio (OR)=0.43, 95% CI: 0.18-0.99], HBC (OR=0.97, 95% CI: 0.94-0.99) and ALC (OR=0.43, 95% CI: 0.20-0.91) were the factors influencing the negative testing results for viral nucleic acid. The rate of re-positive patients was 16.4%. The white blood cell, RBC, HBC and HCT values in re-positive patients were lower than those in non-re-positive patients. The median (interquartile range) values for RBC, HBC and HCT of male re-positive patients were 3.95 (3.37, 4.2) x10¹²/l, 123 (103, 133) g/l and 36.6 (31.1, 39.2)%, respectively, while the RBC, HBC and HCT of female re-positive patients were 3.54 (3.13, 3.74) x10¹²/l, 115 (102, 118) g/l and 34.2 (28.5, 34.9)%, respectively. It was determined that RBC, HBC and HCT values had moderate accuracy in predicting SARS-CoV-2 recurrence in patients with COVID-19 using receiver operating curve analysis. The present study suggested that RBC may have an important role in the pathogenesis of COVID-19.

Vector-borne zoonotic blood parasites in wildlife from Ecuador: A report and systematic review

Background and Aim:

Ecuador is a hugely diverse country, but information on infectious diseases in local wild animals is scarce. The aim of this study was to screen the presence of blood parasites in free-ranging wild animals admitted to the Wildlife Hospital at Universidad San Francisco de Quito, from April 2012 to January 2019.

Materials and Methods:

We identified blood parasites by microscopic observation of blood smears from free-ranging wildlife species that attended the Wildlife Hospital of Universidad San Francisco de Quito (Ecuador) from April 2012 to January 2019.

Results:

The microscopic evaluations of animals as potential reservoirs for vector-borne zoonotic blood parasites revealed the presence of Anaplasma spp., Babesia spp., Ehrlichia spp., Hepatozoon spp., microfilaria, Mycoplasma spp., and Trypanosoma spp. in previously unreported wildlife species. In addition, we performed a systematic review to understand the current knowledge gaps in the context of these findings.

Conclusion:

Our data contribute to the knowledge of blood parasites in wildlife from Ecuador. Furthermore, the potential transmission of these parasites to humans and domestic animals, current anthropogenic environmental changes in the region, and the lack of information on this suggest the importance of our results and warrant further investigations on infectious diseases in animals and humans and their relationship with environmental health as key domains of the One Health concept.

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.

Molecular profiling and functional delineation of peroxiredoxin 3 (HaPrx3) from the big-belly seahorses (Hippocampus abdominalis) and understanding their immunological responses

Peroxiredoxins (Prxs) are ubiquitously expressed antioxidant proteins that can protect aerobic organisms from oxidative stress. Here, we characterized the HaPrx3 homolog at the molecular level from big-belly seahorse (Hippocampus abdominalis) and analyzed its functional activities. The coding sequence of HaPrx3 consists of 726 bp, which encodes 241 amino acids. The predicted molecular weight and theoretical isoelectric point (pI) of HaPrx3 was 26.20 kDa and 7.04, respectively. Multiple sequence alignments revealed that the arrangements of domains, catalytic triads, dimers, and decamer interfaces of HaPrx3 were conserved among Prx sequences of other organisms. According to the phylogenetic analysis, HaPrx3 is clustered with the teleost Prx3 subclade. The highest transcript level of HaPrx3 was detected in the ovary tissue among fourteen healthy fish tissues. The mRNA levels of HaPrx3 in blood and liver tissues were significantly (P < 0.05) upregulated in response to lipopolysaccharide (LPS), polyinosinic-polycytidylic (poly I:C), Edwardsiella tarda, and Streptococcus iniae, suggesting its involvement in immune responses. Under functional properties, insulin disulfide reduction assay confirmed the oxidoreductase activity of recombinant HaPrx3. A cell viability assay and Hoechst staining indicated cell survival ability and reduction of apoptotic activity, respectively. Moreover, a peroxidase activity assay verified peroxidase activity, while a metal-catalyzed oxidation (MCO) assay indicated the DNA protection ability of HaPrx3. Collectively, it is concluded that HaPrx3 may play a significant role in oxidative stress and immune responses against pathogenic infections in big-belly seahorses.

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.

Under the light: high prevalence of haemoparasites in lizards (Reptilia: Squamata) from Central Amazonia revealed by microscopy

Blood samples from 330 lizards of 19 species were collected to investigate the occurrence of haemoparasites. Samplings were performed in areas of upland (terra-firme) forest adjacent to Manaus municipality, Amazonas, Brazil. Blood parasites were detected in 220 (66%) lizards of 12 species and comprised four major groups: Apicomplexa (including haemogregarines, piroplasms, and haemosporidians), trypanosomatids, microfilarid nematodes and viral or bacterial organisms. Order Haemosporida had the highest prevalence, with 118 (35%) animals from 11 species. For lizard species, Uranoscodon superciliosus was the most parasitised host, with 103 (87%; n = 118) positive individuals. This species also presented the highest parasite diversity, with the occurrence of six taxa. Despite the difficulties attributed by many authors regarding the use of morphological characters for taxonomic resolution of haemoparasites, our low-cost approach using light microscopy recorded a high prevalence and diversity of blood parasite taxa in a relatively small number of host species. This report is the first survey of haemoparasites in lizards in the study region. It revealed a high diversity of lizard haemoparasites and highlights the need to understand their impacts on hosts.

Morphological and molecular characteristics of hemoparasites in vaillant's frogs (Lithobates vaillanti)

Amphibian populations are declining around the world, and the main reasons are the environmental changes and pathogens. However, there are few studies addressing the interaction and impact of the different pathogens that affect amphibians, such as hemoparasites. These parasites had been described as common in some amphibian species, but unfortunately, their description and characterization are unclear and scarcely spread. The objective of the present study was to evaluate the morphological and molecular characterization of hemoparasites present in vaillant's frogs. Seven frogs of Lithobates vaillanti were captured at the biological station La Florida in Tabasco, Mexico. Blood smears were performed, and results show that 100% of the animals have hemoparasites. Three types of hemoparasites were found. Eighty-five percent of the frogs were positive to Hepatozoon sp., 57% to Lankesterella sp., and 28% to Trypanosoma sp. According to the molecular analysis of the obtained sequences of Trypanosoma sp. and Hepatozoon sp., both protozoans were positioned in between the clusters of parasites of different geographical regions. Nevertheless, no species names were assigned to any of these parasites because more sequences and analysis are needed.

Molecular characterisation and morphological description of two new species of Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina: Hepatozoidae) infecting leukocytes of African leopards Panthera pardus pardus (L.)

Background

The African leopard Panthera pardus pardus (L.) is currently listed as a vulnerable species on the IUCN (International Union for the Conservation of Nature) red list of threatened species due to ongoing population declines. This implies that leopard-specific parasites are also vulnerable to extinction. Intracellular apicomplexan haemoparasites from the genus Hepatozoon Miller, 1908 have been widely reported from wild carnivores in Africa, including non-specific reports from leopards. This paper describes two new haemogregarines in captive and wild leopards from South Africa and provides a tabular summary of these species in relation to species of Hepatozoon reported from mammalian carnivores.

Methods

Blood was collected from nine captive and eight wild leopards at various localities throughout South Africa. Thin blood smears were Giemsa-stained and screened for intraleukocytic haemoparasites. Gamont stages were micrographed and morphometrically compared with existing literature pertaining to infections in felid hosts. Haemogregarine specific primer set 4558F and 2733R was used to target the 18S rRNA gene for molecular analysis. Resulting sequences were compared to each other and with other available representative mammalian carnivore Hepatozoon sequences from GenBank.

Results

Two species of Hepatozoon were found in captive and wild leopards. Of the 17 leopards screened, eight were infected with one or both morphologically and genetically distinct haemogregarines. When compared with other species of Hepatozoon reported from felids, the two species from this study were morphometrically and molecularly distinct. Species of Hepatozoon from this study were observed to exclusively parasitize a particular type of leukocyte, with Hepatozoon luiperdjie n. sp. infecting neutrophils and Hepatozoon ingwe n. sp. infecting lymphocytes. Phylogenetic analysis showed that these haemogregarines are genetically distinct, with Hepatozoon luiperdjie n. sp. and Hepatozoon ingwe n. sp. falling in well supported separate clades.

Conclusions

To our knowledge, this is the first morphometric and molecular description of Hepatozoon in captive and wild African leopards in South Africa. This study highlights the value of using both morphometric and molecular characteristics when describing species of Hepatozoon from felid hosts.

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

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

Aeromonas salmonicida infects Atlantic salmon (Salmo salar) erythrocytes

Aeromonas salmonicida subsp. salmonicida (hereafter A. salmonicida) is the aetiological agent of furunculosis in marine and freshwater fish. Once A. salmonicida invade the fish host through skin, gut or gills, it spreads and colonizes the head kidney, liver, spleen and brain. A. salmonicida infects leucocytes and exhibits an extracellular phase in the blood of the host; however, it is unknown whether A. salmonicida have an intraerythrocytic phase. Here, we evaluate whether A. salmonicida infects Atlantic salmon (Salmo salar) erythrocytes in vitro and in vivo. A. salmonicida did not kill primary S. salar erythrocytes, even in the presence of high bacterial loads, but A. salmonicida invaded the S. salar erythrocytes in the absence of evident haemolysis. Naïve Atlantic salmon smolts intraperitoneally infected with A. salmonicida showed bacteraemia 5 days post-infection and the presence of intraerythrocytic A. salmonicida. Our results reveal a novel intraerythrocytic phase during A. salmonicida infection.

Blood feast: Exploring the erythrocyte-feeding behaviour of the myxozoan Sphaerospora molnari

Aims

As the most abundant cell population in the blood, erythrocytes represent an attractive source of nutrients and a protective niche to a number of pathogens. Previously, we observed the attachment of the myxozoan parasite Sphaerospora molnari to erythrocytes of its host, common carp (Cyprinus carpio), raising a number of questions about the nature of this interaction.

Methods and results

We elucidated the impact of S molnari on the number of erythrocytes in healthy and immunocompromised fish, over a period of 6 weeks. While we observed only a mild decrease in RBC numbers in healthy individuals, we witnessed gradual and finally severe haemolytic anaemia in immunosuppressed fish. Accompanying this overt loss was increased erythropoiesis as represented by an increase of erythroblasts in the blood. In vitro, we demonstrated the uptake of host proteins from CFSE‐labelled erythrocytes, ultimately inducing death of host RBCs, likely for nutrient gain of the parasite. Nevertheless, the results do not exclude a possible role of erythrocyte‐derived proteins in immune evasion.

Conclusion

Overall, the obtained data provide first evidence for the previously unknown appetite of myxozoan parasites for host erythrocytes and create an important framework for future investigations into the molecular mechanisms underlining this interaction.

Haemogregarina daviesensis sp. nov. (Apicomplexa: Haemogregarinidae) from South American lungfish Lepidosiren paradoxa (Sarcopterygii: Lepidosirenidae) in the eastern Amazon region

Based on morphology and morphometry of gametocytes in blood and molecular phylogenetic analysis, we described a new species of hemoparasite from the genus Haemogregarina isolated from Lepidosiren paradoxa in the eastern Amazon region. Haemogregarina daviesensis sp. nov. is characterized by monomorphic gametocytes of varying maturity stage and their dimensions were 16 ± 0.12 μm (range 13-18) in length and 6 ± 0.97 μm (range 5-8) in width. The morphological and morphometric data were not identical with other haemogregarine species from fish. All specimens of L. paradoxa analyzed were infected by H. daviesensis sp. nov. and the parasitemia level was moderate (1-28/2000 blood erythrocytes). Two sequences were obtained from L. paradoxa, and these constituted a monophyletic sister clade to the Haemogregarina species. In addition, H. daviesensis sp. nov. detected here grouped with Haemogregarina sp. sequences isolated from chelonian Macrochelys temminckii, with 99% bootstrap support. This study provides the first data on the molecular phylogeny of an intraerythrocytic haemogregarine of freshwater fish and highlights the importance of obtaining additional information on aspects of the general biology of these hemoparasites in fish populations, in order to achieve correct taxonomic classification.

Molecular insights into the identification and phylogenetics of the cosmopolitan marine fish blood parasite, Haemogregarina bigemina (Adeleorina: Haemogregarinidae)

Haemogregarina bigemina is one of the most prevalent haemogregarines of marine fishes and has long been considered an enigmatic and cosmopolitan species. However, to determine whether H. bigemina truly represents a single global species, or whether it should be partitioned into several species or subspecies, and to confirm its taxonomic status among the Haemogregarina, molecular analysis is required. Here, we provide the first molecular characterisation of H. bigemina from one of its type hosts, Lipophrys pholis, in the UK using 18S rDNA sequences. Phylogenetic and p-distance comparisons of the newly generated H. bigemina sequences with those published from other haemogregarine taxa and related apicomplexans suggest that H. bigemina falls outside of the "Haemogregarina" clade as well as the Adeleorina altogether, forming a separate apicomplexan marine clade, and appears to be in fact more closely related to other non-haemogregarine Apicomplexa genera. Further work including sequences of H. bigemina and H. bigemina-like parasites observed from fishes in other localities is now needed to investigate this further.

Haemogregarine (Apicomplexa: Adeleorina) infection in Vanderhaege's toad-headed turtle, Mesoclemmys vanderhaegei (Chelidae), from a Brazilian Neotropical savanna region

Knowledge of blood parasites in Brazilian chelonians is limited, since they have been recorded in only six species. Mesoclemmys vanderhaegei (Bour) is a freshwater turtle with a wide geographic distribution in Brazil, but there is little information about its natural history. This paper reports on a study of the prevalence and infection intensity of a haemogregarine in two subpopulations of M. vanderhaegei. The study was conducted in two areas of Cerrado in the Upper Paraguay River basin in the state of Mato Grosso, Brazil, between November 2010 and August 2013. Ninety-five (53%) of the 179 turtles captured were positive for haemogregarine parasites. The parasitic forms observed were two morphotypes of intraerythrocytic gametocytes. The prevalence differed between size classes, increasing significantly according to the animals' body size. There was no significant difference between prevalence and sex, or between sampling periods. The mean parasite intensity was 9 parasites/2,000 erythrocytes (0.45%) and the parasite population presented an aggregated distribution, with an aggregation index of 19 and discrepancy of 0.772. This is the first record of a hemoparasite in the freshwater turtle M. vanderhaegei.

Hemogregarine and Rickettsial infection in ticks of toads from northeastern Colombia

The toads Rhinella spp. are in constant contact with humans and domestic animals and are commonly parasitized by ticks, which are also potential vectors of pathogenic microorganisms, such as apicomplexans and rickettsia. However, little is known about microorganisms associated with toad ticks. In this work, we molecularly evaluated the presence of Rickettsia spp. and hemogregarines in ticks of Rhinella horribilis and R. humboldti in the Colombian Caribbean, finding two different species of Rickettsia: the colombianensi strain and one close to R. bellii. In the case of hemogregarines, since only 18S gene sequences are available, it is difficult to define species and place them correctly in a phylogeny, but most of our samples show a 99% identity with Hemolivia stellata, while others identical to each other seem to form another clade within this genre. All collected ticks were identified as Amblyomma dissimile, representing the first time that H. stellata was recorded in this tick. The prevalence of both microorganisms was very high, which makes it necessary to generate robust phylogenies to clarify their taxonomic diversity and to correctly define their ecological role and pathogenicity, which should be taken into account in amphibian conservation plans and veterinary medicine.

The distribution and host-association of a haemoparasite of damselfishes (Pomacentridae) from the eastern Caribbean based on a combination of morphology and 18S rDNA sequences

Coral reefs harbor the greatest biodiversity per unit area of any ecosystem on earth. While parasites constitute the majority of this biodiversity, they remain poorly studied due to the cryptic nature of many parasites and the lack of appropriate training among coral reef ecologists. Damselfishes (Pomacentridae) are among the most abundant and diverse fishes on coral reefs. In a recent study of blood parasites of Caribbean reef fishes, the first ever apicomplexan blood parasites discovered in damselfishes were reported for members of the genus Stegastes. While these blood parasites were characterized as “Haemohormidium-like”, they appear to be distinct from any other known apicomplexan. In this study, we examined host associations, geographic distributions, and provide further insights on the phylogenetic affiliation of this parasite. A combination of morphological characteristics and 18S rDNA sequences suggest that this parasite may be the same species at multiple sites and occurs from the southern to the northern extreme of the eastern Caribbean, although it appears rare in the north. At present it appears to be limited to members of the genus Stegastes and infects all life history stages. It is most common in benthophagous species that occur in high population densities and appears basal to a major monophyletic clade containing species of coccidia, distinct from the Piroplasmida, the order to which Haemohormidium spp. have been assigned. These findings suggest a possible fecal-oral mode of transmission.

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A new species of Haemorhormidium-like apicomplexan blood parasite has recently been discovered in Caribbean damselfishes.

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Morphological and molecular data indicate that it is widespread in the eastern Caribbean.

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This parasite is limited to damselfish species of the genus Stegastes and infects juveniles and adults.

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It is most common in benthophagous species that occur in high population densities.

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This parasite resembles coccidia but 18S rDNA show it to be distinct from known genera, as well as genera of piroplasms.

Parasitaemia data and molecular characterization of Haemoproteus catharti from New World vultures (Cathartidae) reveals a novel clade of Haemosporida

Background

New World vultures (Cathartiformes: Cathartidae) are obligate scavengers comprised of seven species in five genera throughout the Americas. Of these, turkey vultures (Cathartes aura) and black vultures (Coragyps atratus) are the most widespread and, although ecologically similar, have evolved differences in morphology, physiology, and behaviour. Three species of haemosporidians have been reported in New World vultures to date: Haemoproteus catharti, Leucocytozoon toddi and Plasmodium elongatum, although few studies have investigated haemosporidian parasites in this important group of species. In this study, morphological and molecular methods were used to investigate the epidemiology and molecular biology of haemosporidian parasites of New World vultures in North America.

Methods

Blood and/or tissue samples were obtained from 162 turkey vultures and 95 black vultures in six states of the USA. Parasites were identified based on their morphology in blood smears, and sequences of the mitochondrial cytochrome b and nuclear adenylosuccinate lyase genes were obtained for molecular characterization.

Results

No parasites were detected in black vultures, whereas 24% of turkey vultures across all sampling locations were positive for H. catharti by blood smear analysis and/or PCR testing. The phylogenetic analysis of cytochrome b gene sequences revealed that H. catharti is closely related to MYCAMH1, a yet unidentified haemosporidian from wood storks (Mycteria americana) in southeastern USA and northern Brazil. Haemoproteus catharti and MYCAMH1 represent a clade that is unmistakably separate from all other Haemoproteus spp., being most closely related to Haemocystidium spp. from reptiles and to Plasmodium spp. from birds and reptiles.

Conclusions

Haemoproteus catharti is a widely-distributed parasite of turkey vultures in North America that is evolutionarily distinct from other haemosporidian parasites. These results reveal that the genetic diversity and evolutionary relationships of avian haemosporidians are still being uncovered, and future studies combining a comprehensive evaluation of morphological and life cycle characteristics with the analysis of multiple nuclear and mitochondrial genes will be useful to redefine the genus boundaries of these parasites and to re-evaluate the relationships amongst haemosporidians of birds, reptiles and mammals.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2165-5) contains supplementary material, which is available to authorized users.

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.

The genetic basis for the selection of dairy goats with enhanced resistance to gastrointestinal nematodes

Gastrointestinal nematodes (GIN) severely affect small ruminant production worldwide. Increasing problems of anthelmintic resistance have given strong impetus to the search for alternative strategies to control GIN. Selection of animals with an enhanced resistance to GIN has been shown to be successful in sheep. In goats, the corresponding information is comparatively poor. Therefore, the present study was designed to provide reliable data on heritabilities of and genetic correlations between phenotypic traits linked to GIN and milk yield in two major dairy goat breeds (Alpine and Saanen). In all, 20 herds totalling 1303 goats were enrolled in the study. All herds had (i) a history of gastrointestinal nematode infection, (ii) uniform GIN exposure on pasture and (iii) regular milk recordings. For all goats, individual recordings of faecal egg counts (FEC), FAMACHA© eye score, packed cell volume (PCV) and milk yield were performed twice a year with an anthelmintic treatment in between. The collected phenotypic data were multivariately modelled using animal as a random effect with its covariance structure inferred from the pedigree, enabling estimation of the heritabilities of the respective traits and the genetic correlation between them. The heritabilities of FEC, FAMACHA© and PCV were 0.07, 0.22 and 0.22, respectively. The genetic correlation between FEC and FAMACHA© was close to zero and -0.41 between FEC and PCV. The phenotypic correlation between FEC and milk yield was close to zero, whereas the genetic correlation was 0.49. Our data suggest low heritability of FEC in Saanen and Alpine goats and an unfavourable genetic correlation of FEC with milk yield.

Developing an Apicomplexan DNA Barcoding System to Detect Blood Parasites of Small Coral Reef Fishes

Apicomplexan parasites are obligate parasites of many species of vertebrates. To date, there is very limited understanding of these parasites in the most-diverse group of vertebrates, actinopterygian fishes. While DNA barcoding targeting the eukaryotic 18S small subunit rRNA gene sequence has been useful in identifying apicomplexans in tetrapods, identification of apicomplexans infecting fishes has relied solely on morphological identification by microscopy. In this study, a DNA barcoding method was developed that targets the 18S rRNA gene primers for identifying apicomplexans parasitizing certain actinopterygian fishes. A lead primer set was selected showing no cross-reactivity to the overwhelming abundant host DNA and successfully confirmed 37 of the 41 (90.2%) microscopically verified parasitized fish blood samples analyzed in this study. Furthermore, this DNA barcoding method identified 4 additional samples that screened negative for parasitemia, suggesting this molecular method may provide improved sensitivity over morphological characterization by microscopy. In addition, this PCR screening method for fish apicomplexans, using Whatman FTA preserved DNA, was tested in efforts leading to a more simplified field collection, transport, and sample storage method as well as a streamlining sample processing important for DNA barcoding of large sample sets.

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.

Cyrilia sp. (Apicomplexa: Haemogregarinidae) in the Amazonian freshwater stingray Potamotrygon wallacei (cururu stingray) in different hydrological phases of the Rio Negro

Intraerythrocytic parasites are frequently found in fish, including elasmobranchs. The Amazonian rivers present well defined annual hydrological cycles that results in drastic modifications of the environmental conditions with deep implications in the life cycle of the whole associated biota in those fluvial systems. The freshwater stingray Potamotrygon wallacei (stingray cururu) is a new species restricted to the Middle Rio Negro basin and it is subject to strong alterations in their natural habitats (igapós) a result of the constant variations in the water level of Rio Negro. This work demonstrates the occurrence of intraerythrocytic parasite Cyrilia sp. in this stingray species. Additionally, the prevalence and quantification of hemoparasites in different phases of Rio Negro were also established. Field sampling was carried in the Archipelago of Mariuá, Middle Rio Negro, involving different stages of the water cycle. The intraerythrocytic parasites were quantified by direct counting in blood smears using a total counting of 2000 erythrocytes in each blood smear. The presence of parasites intraerythrocytic generates changes in the morphology of blood cell. The largest amount of the hemoparasites was recorded in the drought period. We observed a decreasing tendency in the number of parasites in the blood between the drought periods and inundation. We concluded that the level of Negro River influences the incidence of intraerythrocytic parasites in the cururu stingray and the drought represents the period of larger susceptibility to the infestation.

A new lizard malaria parasite Plasmodium intabazwe n. sp. (Apicomplexa: Haemospororida: Plasmodiidae) in the Afromontane Pseudocordylus melanotus (Sauria: Cordylidae) with a review of African saurian malaria parasites

Background

Saurian malaria parasites are diverse apicomplexan blood parasites including the family Plasmodiidae Mesnil, 1903, and have been studied since the early 1900s. Currently, at least 27 species of Plasmodium are recorded in African lizards, and to date only two species, Plasmodium zonuriae (Pienaar, 1962) and Plasmodium cordyli Telford, 1987, have been reported from the African endemic family Cordylidae. This paper presents a description of a new malaria parasite in a cordylid lizard and provides a phylogenetic hypothesis for saurian Plasmodium species from South Africa. Furthermore, it provides a tabular review of the Plasmodium species that to date have been formally described infecting species of African lizards.

Methods

Blood samples were collected from 77 specimens of Pseudocordylus melanotus (A. Smith, 1838) from Platberg reserve in the Eastern Free State, and two specimens of Cordylus vittifer (Reichenow, 1887) from the Roodewalshoek conservancy in Mpumalanga (South Africa). Blood smears were Giemsa-stained, screened for haematozoa, specifically saurian malaria parasites, parasite stages were photographed and measured. A small volume was also preserved for TEM studies. Plasmodium and Haemoproteus primer sets, with a nested-polymerase chain reaction (PCR) protocol, were employed to target a fragment of the cytochrome-b (cyt-b) gene region. Resulting sequences of the saurian Plasmodium species’ isolates were compared with each other and to other known Plasmodium spp. sequences in the GenBank database.

Results

The presence of P. zonuriae in both specimens of the type lizard host C. vittifer was confirmed using morphological characteristics, which subsequently allowed for the species’ molecular characterisation. Of the 77 P. melanotus, 44 were parasitised by a Plasmodium species, which when compared morphologically to other African saurian Plasmodium spp. and molecularly to P. zonuriae, supported its description as a new species Plasmodium intabazwe n. sp.

Conclusions

This is the first morphological and molecular account of Plasmodium species within the African endemic family Cordylidae from South Africa. The study highlights the need for molecular analysis of other cordylid Plasmodium species within Africa. Future studies should also include elucidating of the life-cycles of these species, thus promoting the use of both morphological and molecular characteristics in species descriptions of saurian malaria parasites.

First report and description of a Cyrilia sp. (Apicomplexa: Haemogregarinidae) from a freshwater Cururu Stingray Potamotrygon cf. histrix (Elasmobranchii: Potamotrygonidae), from the Amazon Region, Brazil

A haemogregarine is described in 12 cururu stingray (Potamotrygon cf. histrix), from Mariuá Archipelago, Negro River, in the Brazilian Amazon Basin. All animals, both male and female, were parasitized by the haemogregarine and parasitaemia varied between 0.8% and 10% of erythrocytes. The stages observed included trophozoites or merozoites, suspected meronts, and gamonts presumed to be of two types, macrogamonts and microgamonts. Most stages were observed inside mature erythrocytes, while others were extracellular. The stages observed were most similar to those characteristics of the genus Cyrilia, than to any other fish haemogregarine and may represent a new Cyrilia species.

Redescription, molecular characterisation and taxonomic re-evaluation of a unique African monitor lizard haemogregarine Karyolysus paradoxa (Dias, 1954) n. comb. (Karyolysidae)

BACKGROUND

Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbé, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors' knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement.

METHODS

Specimens of Varanus albigularis albigularis Daudin, 1802 (Rock monitor) and Varanus niloticus (Linnaeus in Hasselquist, 1762) (Nile monitor) were collected from the Ndumo Game Reserve, South Africa. Upon capture animals were examined for haematophagous arthropods. Blood was collected, thin blood smears prepared, stained with Giemsa, screened and micrographs of parasites captured. Haemogregarine morphometric data were compared with the data for named haemogregarines of African varanids. Primer set HepF300 and HepR900 was employed to target a fragment of the 18S rRNA gene and resulting sequences compared with other known haemogregarine sequences selected from the GenBank database.

RESULTS

Hepatozoon paradoxa was identified infecting two out of eight (25 %) V. a. albigularis and a single (100 %) V. niloticus examined. Phylogenetic analyses revealed that H. paradoxa clustered with the 'Karyolysus' clade, and not with those of reptilian Hepatozoon spp.

CONCLUSIONS

In addition to this being the first morphological and molecular characterisation of a haemogregarine within the African Varanidae, it is the first report of a species of Karyolysus infecting the monitor lizard family. Furthermore, this constitutes now only the third described and named Karyolysus species for which there is a nucleotide sequence available.

Absence of haemoparasite infection in the fossorial amphisbaenian Trogonophis wiegmanni

Blood parasites such as haemogregarines and haemosporidians have been identified in almost all groups of vertebrates. However, very little is known about biodiversity of these parasites and their effects on some major groups of reptiles such as amphisbaenians, a distinctive group with many morphological and ecological adaptations to fossorial life. Conditions of the fossorial environment might also affect host-parasite relationships. We investigated the presence and the potential prevalence of three genera of haemoparasitic aplicomplexan blood parasites (Hepatozoon, Plasmodium and Haemoproteus) in the amphisbaenian Trogonophis wiegmanni, a fossorial worm lizard species from North West Africa. Blood parasite infection was not detected in T. wiegmanni, both in visual surveys of blood smears and using molecular methods to detect DNA of such parasites in the blood of the potential amphisbaenian hosts. We discuss how conditions of the fossorial environment might affect blood parasitaemias in amphisbaenians as well as in other fossorial reptiles.

Morphological and molecular characterisation of Haemogregarina sp. (Apicomplexa: Adeleina: Haemogregarinidae) from the blood of the Caspian freshwater turtle Mauremys caspica (Gmelin) (Geoemydidae) in Iran

To date, a number of species of Haemogregarina have been described from different turtle hosts, mainly based on the morphology of the developmental stages detected in the host erythrocytes. The diversity and overlapping morphological features in the old and recent descriptions has led to considerable complications in the taxonomy of Haemogregarina spp. In this study, different stages of maturity and developing gamonts of a putative new species of Haemogregarina were detected in erythrocytes of the Caspian turtle Mauremys caspica (Gmelin) (Geoemydidae) originating from a southern province in Iran. Although some of the morphological characteristics were consistent with Haemogregarina stepanowi Danilewsky, 1885, some new observations were made, particularly in the gamont stage. The phylogenetic analysis based on 18S rDNA sequences revealed that the present isolate appears as basal to a large clade of Haemogregarina spp. with sequences available in the GenBank database. In accordance with the phylogenetic results, the present Iranian isolate showed a higher degree of interspecific divergence (up to 3.3%) compared to the data for the taxa available in the GenBank database. Thus, molecular data indicate that this isolate may represent a new species. However, further genetic analyses are needed as a complementary tool to the morphological characterisation in order to elucidate the phylogenetic relationships of Haemogregarina spp.

Parasitization by Sauroplasma sp. (Apicomplexa: Haemohormidiidae) in Chelonian Podocnemis expansa (Testudines: Podocnemididae) in the Brazilian Amazon

The prevalence and parasitemia of the piroplasm Sauroplasma sp. were evaluated in the Amazon chelonian Podocnemis expansa in Brazil. Samples were collected from 75 chelonians from 3 locations, including a commercial breeding facility, an indigenous subsistence breeding facility, and a wild population. Sauroplasma were found in 72% (54/75) of the chelonians, and the prevalence varied among the sampling sites. No significant correlations were found between the prevalence and the sex and body condition index of the chelonians. The mean parasitemia rate was 44.14/2,000 erythrocytes (2.2%), and no significant correlation was found between the parasitemia and sex and body condition index of the chelonians. These results suggest that the parasite is not pathogenic to P. expansa. No ectoparasites were found in the animals evaluated in the present study; however, due to the aquatic habit of the chelonian, it is likely that the piroplasm is transmitted by leeches and not by ticks, as would be expected for piroplasms.

Prevalence and parasitemia of Haemogregarina sp. in Podocnemis expansa (Testudines: Podocnemididae) from the Brazilian Amazon

Seventy-five turtles Podocnemis expansa in the Brazilian Amazon were examined for the presence of ectoparasites and hemoparasites. Samplings were performed in three study areas in the state of Tocantins, Brazil. Twenty-five specimens were sampled per study area (a commercial breeding facility, an indigenous subsistence breeding facility and a wild population of the Javaés River). Hemoparasites of the genus Haemogregarina were found in 66% (50/75) of the turtle specimens, and the infections were restricted to the commercial breeding facility and to the wild population of the Javaés River. The mean level of parasitemia was 54/2,000 erythrocytes (2%). There was no correlation between the body condition index of the chelonians and the level of parasitemia, with no significant difference between genders. No leeches were observed during the physical exams in any of the study areas, but the specimens from the commercial breeding facility were in poor physical condition with shell deformities and the presence of a relatively high amount of skin ulcerations, most likely caused by fungi and bacteria. This was the first study to record the occurrence of hemogregarines on a population scale in P. expansa and helps to increase knowledge about hemoparasites in chelonians in Brazil.

Biodiversity of frog haemoparasites from sub-tropical northern KwaZulu-Natal, South Africa

Since South Africa boasts a high biodiversity of frog species, a multispecies haemoparasite survey was conducted by screening the blood from 29 species and 436 individual frogs. Frogs were collected at three localities in sub-tropical KwaZulu-Natal, a hotspot for frog diversity. Twenty per cent of the frogs were infected with at least one of five groups of parasites recorded. Intraerythrocytic parasites comprising Hepatozoon, Dactylosoma, and viral or bacterial organisms, as well as extracellular parasites including trypanosomes and microfilarid nematodes were found. A significant difference (P < 0.01) in the prevalence of parasitaemia was found across species, those semi-aquatic species demonstrating the highest, followed by semi-terrestrial frog species. None of those species described as purely terrestrial and aquatic were infected. Hepatozoon and Trypanosoma species accounted for most of the infections, the former demonstrating significant differences in intensity of infection across species, families and habitat types (P = 0.028; P = 0.006; P = 0.007 respectively). Per locality, the first, the formally protected Ndumo Game Reserve, had the highest biodiversity of haemoparasite infections, with all five groups of parasites recorded. The other two sites, that is the area bordering the reserve and the Kwa Nyamazane Conservancy, had a lower diversity with no parasite infections recorded and only Hepatozoon species recorded respectively. Such findings could be ascribed to the anthropogenic impact on the latter two sites, the first by the rural village activities, and the second by the bordering commercial sugar cane agriculture. Future studies should include both morphological and molecular descriptions of the above parasites, as well as the identification of potential vectors, possibly clarifying the effects human activities may have on frog haemoparasite life cycles and as such their biodiversity.

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.