First helminthological data on the Iberian adder, Vipera seoanei.

The helminth fauna present in the gut contents of Iberian adders, Vipera seoanei (Squamata: Viperidae), were characterised and analysed in respect to biological and eco-geographic factors that may affect the occurrence and diversity of helminths in this species. A total of 317 samples of preserved stomachs and intestines, covering the distributional range of V. seoanei, were examined. Similar to other Vipera species from the Iberian Peninsula, the helminth fauna was also impoverished in V. seoanei, but unlike other Vipera species from Central and East Europe, helminths were mostly found in adult vipers, and occurred in vipers located at the periphery of the species range, characterised by low elevation, high temperature and precipitation levels, and abundant pastures.

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

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

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

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

Hepatozoon pyramidumi sp. n. (Apicomplexa: Adeleorina) from the blood of Echis pyramidum: morphology and SSU rDNA sequence / Hepatozoon pyramidumi sp. n. (Apicomplexa: Adeleorina) do sangue de Echis pyramidum: morfologia e sequência de SSU rDNA

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

Resumo Hepatozoon pyramidumi sp. n. é descrito a partir do sangue da víbora em escamas e quilhas serrilhadas, Echis pyramidum, capturada na Arábia Saudita. Cinco de dez espécimes de víbora examinadas (50%) foram encontradas infectadas com Hepatozoon pyramidumi sp. n. com nível de parasitemia de 20% a 30%. A infecção foi restrita apenas aos eritrócitos. Foram observadas duas formas morfologicamente diferentes de estágios intra-eritrocíticos: gamontes de tamanho pequeno e madura. As formas menores de gamontes apresentaram média de 10,7 × 3,5 μm. Os gamontes maduros apresentaram forma de salsicha, com pequenos polos recurvados, medindo 16,3 × 4,2 μm, em média. Os eritrócitos infectados estavam aumentados de tamanho; seus núcleos encontravam-se deformados e, algumas vezes, deslocados de sua posição central, quando comparados às células normais não-infectadas. Foram observados estágios merogônicos em células endoteliais pulmonares e nas células do parênquima hepático. Os merontes maduros apresentavam 17,8 × 13,6 µm e continham merozoítos em forma de banana com tamanho médio de ~ 15 × 2 µm. A análise filogenética baseada nas sequências SSU rDNA agrupou Hepatozoon pyramidumi sp. n com Hepatozoon spp. detectados em répteis de várias regiões geográficas. Por meio de análises morfológicas e moleculares com espécies intimamente relacionadas, demonstrou-se a singularidade dessa nova espécie de Hepatozoon.

Armillifer-Infected Snakes Sold at Congolese Bushmeat Markets Represent an Emerging Zoonotic Threat.

African pythons (Pythonidae) and large vipers (Bitis spp.) act as definitive hosts for Armillifer armillatus and Armillifer grandis parasites (Crustacea: Pentastomida) in the Congo Basin. Since the proportion of snakes in bushmeat gradually increases, human pentastomiasis is an emerging zoonotic disease. To substantiate the significance of this threat, we surveyed snakes offered for human consumption at bushmeat markets in the Kole district, Democratic Republic of the Congo, for the presence of adult pentastomids. In Bitis vipers (n = 40), Armillifer spp. infestations exhibited an 87.5% prevalence and 6.0 median intensity. Parasite abundance covaried positively with viper length, but not with body mass. In pythons (n = 13), Armillifer spp. exhibited a 92.3% prevalence and 3.5 median intensity. The positive correlations between parasite abundance and python length or mass were statistically nonsignificant. Ninety-one percent of A. grandis were discovered in vipers and 97% of infected vipers hosted A. grandis, whereas 81% of A. armillatus specimens were found in pythons and 63% of infected pythons hosted A. armillatus. Thus, challenging the widespread notion of strict host specificity, we found 'reversed' infections and even a case of coinfection. In this study, we also gathered information about the snake consumption habits of different tribal cultures in the area. Infective parasite ova likely transmit to humans directly by consumption of uncooked meat, or indirectly through contaminated hands, kitchen tools or washing water.

Genetic Identification of Spirometra decipiens Plerocercoids in Terrestrial Snakes from Korea and China.

Human sparganosis is a zoonotic disease caused by infection with larval forms (procercoid/plerocercoid) of Spirometra spp. The purpose of this study was to identify Spirometra spp. of infected snakes using a multiplex PCR assay and phylogenetic analysis of mitochondrial DNA sequence data from the spargana of terrestrial snakes obtained from Korea and China. A total of 283 snakes were obtained that included 4 species of Colubridae comprising Rhabdophis tigrinus tigrinus (n=150), Dinodon rufozonatum rufozonatum (n=64), Elaphe davidi (n=2), and Elaphe schrenkii (n=7), and 1 species of Viperidae, Agkistrodon saxatilis (n=60). The snakes were collected from the provinces of Chungbuk, Chungnam, and Gyeongbuk in Korea (n=161), and from China (n=122). The overall infection rate with spargana was 83% (235/283). The highest was recorded for D. rufozonatum rufozonatum (100%), followed by A. saxatilis (85%) and R. tigrinus tigrinus (80%), with a negative result for E. davidi (0%) and E. schrenkii (0%). The sequence identities between the spargana from snakes (n=50) and Spirometra erinaceieuropaei (KJ599680) or S. decipiens (KJ599679) control specimens were 90.8% and 99.2%, respectively. Pairwise genetic distances between spargana (n=50) and S. decipiens ranged from 0.0080 to 0.0107, while those between spargana and S. erinaceieuropaei ranged from 0.1070 to 0.1096. In this study, all of the 904 spargana analyzed were identified as S. decipiens either by a multiplex PCR assay (n=854) or mitochondrial cox1 sequence analysis (n=50).

Morphological study of Ophidascaris excavata Hsü & Hoeppli, 1931 (Ascaridida: Ascarididae) from Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae).

Ophidascaris excavata Hsü & Hoeppli, 1931 is a poorly known ascaridid parasite reported from the short-tailed pit viper Gloydius brevicaudus (Stejneger) (Reptilia: Viperidae) in China. In the present paper, the detailed morphology of this nematode was studied using light and scanning electron microscopy (SEM) based on newly collected material. The results revealed several important, but previously unreported, morphological features, including the presence of one pair of small, finger-like prolongations on each lip, narrow cervical alae beginning well posterior to the base of the ventrolateral lips and the second pair of postcloacal ventro-lateral papillae being double; in addition, there is no intestinal caecum. These supplementary morphological and morphometric data, especially the detailed morphological features obtained herein under SEM, would help us to understand the relationships of O. excavata with its congeners and enable us to diagnose this species more accurately.

High Prevalence of Porocephalus crotali Infection on a Barrier Island (Cumberland Island) off the Coast of Georgia, with Identification of Novel Intermediate Hosts.

Porocephalus crotali is a pentastomid parasite that uses crotaline snakes as definitive hosts and a variety of rodents as intermediate hosts. A study of definitive and intermediate pentastome hosts on Cumberland Island, Georgia, revealed high prevalence of P. crotali infection in crotalid snakes as well as several mammalian species. Despite the presence of numerous nymphs in some animals, clinical signs of disease were not observed. In intermediate hosts, the liver, mesentery, and reproductive organs were most commonly infected. No gross evidence of tissue damage was noted in association with the numerous encysted nymphal pentastomes, and histopathology demonstrated minimal reaction to the encysted nymphs. Partial 18S rRNA gene sequences confirmed the parasites were P. crotali. In contrast to many previous reports in rodents, the prevalence on this barrier island was high, and this is the first report of Virginia opossums (Didelphis virginiana) and any insectivore species as intermediate hosts. Although generally not considered pathogenic, the long-term consequences of high nymph intensities on individuals deserve attention.

Caryospora bigenetica (Apicomplexa: Eimeriidae) in South America: new hosts and distribution records.

The coccidian Caryospora bigenetica was first described in the snake Crotalus horridus (Viperidae) from United States of America. This study represents the first record of the occurrence of C. bigenetica in snakes in South America. Feces were sampled between November 2013 and May 2014 from 256 wild snakes maintained in scientific breeding facilities in the states of Mato Grosso do Sul (MS; n = 214) and Rio de Janeiro (RJ; n = 42), Brazil. Caryospora bigenetica was found in 14 (5.6%) snakes, all belonging to the family Viperidae. Ten Bothrops moojeni and two Crotalus durissus from MS were infected. The coccidian was also found in one C. durissus and in one Bothrops jararacussu from the state of RJ. The oocysts were spherical with a double wall, the exterior lightly mammillated, striations apparent in transverse view, 13.0 µm (12 - 14); polar granule fixed in the internal wall. Sporocysts oval or pyriform, 10.0 × 8.0 µm (9 - 11 × 8 - 9); Stieda body discoid; sub-Stieda body present; sporocyst residuum present, formed by a group of spheroid bodies between sporozoites. This study increases the number of viperid hosts of C. bigenetica and expands the geographical distribution to South America.

LABORATORY STUDIES ON THE POSSIBILITY OF CULEX QUINQUEFASCIATUS TO HARBOR HEPATOZOON SP. INFECTING CERASTES CERASTES CERASTES VIPER IN EGYPT.

A successful experimental infection of Culex quinquefasciatus with Hepatozoon sp. infecting Cerastes cerastes cerastes viper was carried out under laboratory conditions of 24 +/- 3 degrees C and 60-70% R. H. The period monitored for complete sporogonic cycle was 21 days. The effect of high parasitimic blood meal was nonsignificant (P>0.05) on preoviposition period and hatchability. Meanwhile a highly significant reduction was observed in oviposition rate, number of deposited eggs, number of hatched larvae and longevity (P<0.01). On the contrary moderate infection with Hepatozoon revealed a great significant increase in fecundity (P<0.01) and a nonsignificant decrease in longevity (P>0.05)

Choleoeimeria salaselensis sp. n. (Apicomplexa: Eimeriidae) from the gall bladder of the horned viper Cerastes gasperettii (Serpentes: Viperidae) in Saudi Arabia.

Oocyst morphology and endogenous developmental stages are described for Choleoeimeria salaselensis sp. n. from the gall bladder of 10 horned vipers, Cerastes gasperettii Leviton and Anderson, in Saudi Arabia. Sporulated oocysts are ellipsoidal, 23 x 15 (22-25 x 14-17) microm, length/width ratio (L/W) 1.5 (1.4-1.6), each with 4 sporocysts (Eimeria-like), but lack a micropyle, polar granules and oocysts residuum. Sporocysts are ellipsoidal, 8 x 5 (7-9 x 5-) microm, L/W 1.5 (1.4-1.6), and Stieda, substieda and parasubstieda bodies are all absent, but a longitudinal suture, which divided the sporocysts into 2 plates, is present. Endogenous development is confined to epithelial cells in the bile duct and gall bladder; mature meronts were 11 x 7 microm, each with 10-16 merozoites, microgamonts were -12 microm wide, and macrogamonts were -16 microm wide with a prominent nucleus and wall-forming bodies. Given these two diagnostic features, sporocysts with a suture and composed of two plates and endogenous development limited to the biliary epithelium, we believe this coccidium is best classified as a member of Choleoeimeria Paperna et Landsberg, 1989. There are 5 known Eimeria species from vipers that have sporocysts somewhat similar in size to those of our new form, but all of them have much larger oocysts and larger sporocysts, some of which differ significantly in shape; there are not yet any Choleoeimeria species known from the Viperidae.

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

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

Description of gamontogonic and sporogonic stages of Hepatozoon spp. (Apicomplexa, Hepatozoidae) from Caudisoma durissa terrifica (Serpentes, Viperidae).

Three specimens of Caudisoma durissa terrifica infected with Hepatozoon spp. were studied. One was parasitized by one type of gamont and the other two were each infected by two morphologically different gamonts. Utilizing morphology and morphometry analysis, we concluded that three types of gamonts were very similar and may represent the same Hepatozoon species, but at least three different Hepatozoon species were infecting the C. durissa terrifica snakes in this study. Some of this species caused erythrocyte modifications. The sporogonic development of Hepatozoon sp. was observed from 12 h to the 20th day after female Culex quinquefasciatus blood meals.

Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes.

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 °C temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 °C temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

A case of a facultative life-cycle diversification in the fluke Pleurogenoides sp. (Lecithodendriidae, Plagiorchiida).

Numerous specimens of the native, intestinal digenean fluke Pleurogenoides sp. (Lecithodendriidae, Plagiorchiida), a genus known for the simultaneous co-existence of genuine adults and progenetic, adult-like metacercaria, were found by chance parasitizing in the oesophagus of a recently imported, tropical Bristly Bush Viper (Atheris hispida). The snake had before been force-fed with native water frogs, the assumed definitive host of these flukes. Hence water frogs act as the second intermediate host or as a paratenic host for Pleurogenoides flukes, as they must house progenetic fluke larvae, which develop to genuine adults when transmitted to an appropriate consecutive host, the ancestral definitive host, a reptile. The European Pleurogenoides fluke species seem to display a facultative life-cycle diversification, they can adjust their life-history strategy according to their immediate transmission opportunities. This phenotypic plasticity allows the parasite to respond quickly to any changes in the abundance of a host; usually this biological oddity results in a life-cycle truncation by the elimination of the definitive host.

Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes / Ciclo dioxênico em Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae)parasitando serpentes da família Viperidae

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10 percent relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10 percent relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

Amblyomma rotundatum é um carrapato da família Ixodidae, parasito de animais pecilotérmicos, e que se reproduz exclusivamente por partenogênese. Este carrapato é frequentemente relatado infestando répteis e anfíbios em condições naturais e, às vezes, em animais de cativeiro. Ele já foi relatado no Brasil e em vários outros países das Américas do Sul, Central e do Norte. Embora muitos estudos sobre sua biologia tenham sido publicados, nunca foram utilizados ofídios como hospedeiros e, tão pouco, foram realizados ensaios com os estádios parasitários sob condições controladas de temperatura, umidade e iluminação. O objetivo deste experimento foi estudar o ciclo biológico de A. rotundatum se alimentando em serpentes da família Viperidae sob condições ambientais controladas a 27 ± 1 ºC de temperatura, 85 ± 10 por cento de umidade relativa do ar e 12:12 horas de fotoperíodo para estágios parasitários; assim como sob condições iguais a 27 ± 1 ºC de temperatura, 85 ± 10 por cento de umidade relativa do ar e escotofase em estufas de germinação para estádios não parasitários. A duração total do ciclo de vida variou de 56 a 163 dias (média de 105 dias). Observou-se ciclo dioxênico para a a maior parte da população dos ixodídeos em estudo.

On a Haemogregarine sp. (Protozoa, Apicomplexa, Adeleina) naturally infecting the viper Bitis arientans in Saudi Arabia with reference to the host-parasite relationship.

The study described the developmental stages of a haemogregarine species in the blood and tissues of the viper Bitis arientans. Two out of 9 (22.2%) snakes from the south western region of Saudi Arabia, and recorded for the first time in such locality. The erythrocytic parasites were differentiated into three forms: the youngest form (trophozoite) measuring 7.34 +/- 0.16 x 3.38 +/- 0.07 microm; the intermediate form (developing gametocyte) measuring 13.36 +/-0.20 x 5.11 +/- 0.11 microm and the largest form (mature gametocyte) measuring 18.69 +/- 0.32 x 4.32 +/- 0.16 microm. None of the leucocytes seemed to be parasitized. Also, two types of meronts were detected in lung endothelial cells of infected vipers. Small meronts (micromeronts) measured 21.86 +/- 0.28 x 16.13 +/- 0.25 microm and yielded about 12 merozoites. The large meronts (macromeronts) measured 38.09 +/- 0.33 x 21.52 +/- 0.32 microm and yielded 28-42 merozoites. Random distribution of nuclei was observed in early meronts of both sizes, meanwhile peripheral arrangement of nuclei characterizing the subsequent developing events of meronts (ectomerogony). Histopatho-logical studies showed that the infected erythrocytes were hypertrophied, mechanically stretched and their cytoplasm was faintly stained due to dehaemoglobinization. The host cell nucleus was elongated and laterally displaced. Trabeculae of the infected lung exhibited marked thickening and alveoli were collapsed in various degrees. Haemorrhagic foci and spongy structures were detected in some infected lung tissues. Formation of fibrous tissues around the meronts was seen in some foci.

Light and electron microscopic study on a haemogregarine species infecting the viper cerastes Cerastes gasperitti from Saudi Arabia.

A Haemogregarine sp. infecting the Viper Cerastes cerastes gasperitti (35%) from K.S.A. was recorded for the 1st time. Parasites were recorded exclusively in the red blood cells of the Vipers. Erythrocytic parasites measured 17.5 x 3 microm with a nucleus of 8.1 x 2.5 microm. Mature Schizonts of 30 x 2.5 microm and producing 18-30 merozoites by ectomerogony were reported in the endothelial cells of blood capillaries of different internal organs (liver, spleen and lung). The merozoites measured 13 x 3.5 microm and these were similar to the stages in the red blood cells. The motile stages of the parasite recorded in the present study showed all the general architectures of the Apicomplexa with some pecularities such as presence of micronemes and rhoptries at both sides of the nucleus and the occurance of large number of subpellicular microtubules (80-90) extending to the posterior end of the parasite.

[On the occurrence of the nematode Oswaldocruzia filiformis (Strongylida: Molineidae) in Karelia].

Contents of the intestines of the viper Vipera berus (L., 1758) from Kizhi archipelago (Lake Onego) was examined. Helminth fauna of the viper was found to include single nematode species, Oswaldocruzia filiformis Goeze, 1782 (Strongylida: Molineidae). Prevalence of the invasion was 60%, intensity of the invasion was 1-8 specimens per host, index of abundance was 1.92 specimens. Measurements and pictures of the parasite are given. Morphometric data on the nematode from viper are compared with those from other host species.

Phylogeny of snake trypanosomes inferred by SSU rDNA sequences, their possible transmission by phlebotomines, and taxonomic appraisal by molecular, cross-infection and morphological analysis.

Blood examination by microhaematocrit and haemoculture of 459 snakes belonging to 37 species revealed 2.4% trypanosome prevalence in species of Viperidae (Crotalus durissus and Bothrops jararaca) and Colubridae (Pseudoboa nigra). Trypanosome cultures from C. durissus and P. nigra were behaviourally and morphologically indistinguishable. In addition, the growth and morphological features of a trypanosome from the sand fly Viannamyia tuberculata were similar to those of snake isolates. Cross-infection experiments revealed a lack of host restriction, as snakes of 3 species were infected with the trypanosome from C. durissus. Phylogeny based on ribosomal sequences revealed that snake trypanosomes clustered together with the sand fly trypanosome, forming a new phylogenetic lineage within Trypanosoma closest to a clade of lizard trypanosomes transmitted by sand flies. The clade of trypanosomes from snakes and lizards suggests an association between the evolutionary histories of these trypanosomes and their squamate hosts. Moreover, data strongly indicated that these trypanosomes are transmitted by sand flies. The flaws of the current taxonomy of snake trypanosomes are discussed, and the need for molecular parameters to be adopted is emphasized. To our knowledge, this is the first molecular phylogenetic study of snake trypanosomes.