A new species of myxosporean (Sphaeromyxidae), a parasite of lined seahorses, Hippocampus erectus, from the Gulf of Mexico.

Sphaeromyxa cannolii sp. n. is described from the bile ducts of aquaria-maintained lined seahorses (Hippocampus erectus) from the Gulf of Mexico. Spores of the new species are linear, 17-18 µm long and 5-6 µm wide, with flattened tips; polar capsules measure 4 × 3 µm. Routine necropsies of H. erectus following planned death revealed liver inflammation, bile duct obstruction, bile accumulation, and myxozoan parasites in the bile ducts of 11 of 40 animals sampled (27.5%). The presence of S. cannolii in an aquaculture setting should prompt keepers to carefully quarantine new animals and exclude annelid fauna, a potential intermediate host of myxozoans.

Apparent absence of Parahaemoproteus lophortyx and other hematozoa in North Florida populations of bobwhite quail (Colinus virginianus).

Parahaemoproteus lophortyx (formerly Haemoproteus lophortyx) is known to infect populations of bobwhite quail (Colinus virginianus) in California and to lead to considerable mortalities in these birds. Populations of bobwhite quail in Florida have never been surveyed for the presence of this parasite. The goal of this study was to determine whether P. lophortyx is present in populations of bobwhite quail in north Florida. To achieve this goal, blood was drawn from 294 bobwhite quail from 4 study sites in north Florida from 19 June 2007 to 1 August 2007. Blood smears were made, stained with Giemsa, and examined under x1,000 magnification for the presence of Parahaemoproteus lophortyx. No gametocytes were noted in any of the blood smears. Thirty randomly chosen samples were examined via polymerase chain reaction (PCR). This procedure may detect parasitemias too low to detect by microscopy. No PCR-positive samples were detected, however, adding support to the absence of hematozoa in Florida populations of bobwhite quail.

Massive visceral pentastomiasis caused by Porocephalus crotali in a dog.

The testes of a 5-year-old, male, crossbred Schnauzer dog were the indicator organs for detection of massive pentastomiasis. Necropsy revealed numerous additional encysted parasites within the mesenteric lymph nodes, omentum, liver, sub-serosa of the small and large intestines, mesentery, and lungs. The nymphs had a pseudosegmented body, containing large eosinophilic glands and a chitinous cuticle with characteristic pores. Their hook configuration was consistent with that of Porocephalus. A pentastomid-specific 18S rRNA polymerase chain reaction (PCR) was designed and used to amplify template for sequencing. The sequence of the PCR product was 99.7% homologous with the reference sequence for P. crotali. This pentastomid parasite has been reported in North American snakes of genera Crotalus and Agkistrodon. Mammals are intermediate hosts, and snakes are the definitive hosts. Porocephalus crotali has been reported in dogs only once, and molecular methods have not been used previously to identify the species in clinical pentastomiasis.

Helminth fauna of the nine-banded armadillo (Dasypus novemcinctus) in north-central Florida.

The gastrointestinal tracts of 32 free-ranging, 9-banded armadillos (Dasypus novemcinctus) from north-central Florida were examined for the presence of helminths during July 1991 to November 1993. Aspidodera sp. (Nematoda: Aspidoderidae), most closely resembling Aspidodera sogandaresi, were recovered from 20 of 32 armadillos examined. Total numbers of A. sogandaresi ranged from 1 to 1,021 per infected animal, and followed an inverse correlation to body condition index for those animals. The cystacanth stage of 1 acanthocephalan, Macracanthorhynchus ingens, was present in 1 armadillo, and is the first report of M. ingens in the 9-banded armadillo. The present study contributes to the known natural history of the 9-banded armadillo, an important animal research model.

A new pronocephalid, Pleurogonius tortugueroi n. sp. (Digenea), from the intestine of green sea turtles (Chelonia mydas) in Costa Rica.

A new species of trematode, Pleurogonius tortugueroi n. sp. (Digenea: Pronocephalidae) is described from the lower intestine of green sea turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica. The new species differs from all other species of Pleurogonius by having a short oesophagus and oval testes close to lateral posterior limit of the body. It differs from all other species, except P. malaclemys Hunter 1961, by having an ovary between the testes; moreover the latter species is a parasite of freshwater turtles. All others members of the genus have a long oesophagus, testes placed to some distance from the posterior end, and the ovary is pretesticular. The new species appears most closely related to P. linearis Looss, 1901 but differs from it by having a different body shape, lappets of the head collar close at the cecal bifurcation level, a longer vitellarian field, different testis shape and position, ovary intertesticular, and different egg size.

Lack of Sarcocystis neurona antibody response in Virginia opossums (Didelphis virginiana) fed Sarcocystis neurona-infected muscle tissue.

Serum was collected from laboratory-reared Virginia opossums (Didelphis virginiana) to determine whether experimentally infected opossums shedding Sarcocystis neurona sporocysts develop serum antibodies to S. neurona merozoite antigens. Three opossums were fed muscles from nine-banded armadillos (Dasypus novemcinctus), and 5 were fed muscles from striped skunks (Mephitis mephitis). Serum was also collected from 26 automobile-killed opossums to determine whether antibodies to S. neurona were present in these opossums. Serum was analyzed using the S. neurona direct agglutination test (SAT). The SAT was modified for use with a filter paper collection system. Antibodies to S. neurona were not detected in any of the serum samples from opossums, indicating that infection in the opossum is localized in the small intestine. Antibodies to S. neurona were detected in filter-paper-processed serum samples from 2 armadillos naturally infected with S. neurona.

Pars plana vitrectomy for the treatment of ophthalmomyiasis interna posterior in a dog.

Unilateral chorioretinitis caused by ophthalmomyiasis interna posterior in a 5-month-old, female spayed Dachshund is reported. Larva removal by pars plana vitrectomy was performed after an unsuccessful photocoagulation of the organism. The larva was intact after surgical removal and was identified as a first stage instar Cuterebra spp. larva. The eye remains visual and comfortable with no signs of residual or recurrent inflammation postoperatively. This report describes, for the first time, the successful surgical retrieval of an intravitreal fly larva in a dog using vitrectomy techniques without sacrificing either the globe or vision, and taxonomic identification of the parasite.

Besnoitia oryctofelisi n. sp. (Protozoa: Apicomplexa) from domestic rabbits.

A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52 x 45 microm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10-14 x 10-13 microm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana, and B. darlingi of opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia, a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina.

Naturally occurring Sarcocystis infection in domestic cats (Felis catus).

Equine protozoal myeloencephalitis is an important neurological disease of horses in the United States. Consequently, there is an active research effort to identify hosts associated with the primary causative agent, Sarcocystis neurona. The purpose of this study was to determine whether the domestic cat (Felis catus) is a natural host for S. neurona. Muscle sections from 50 primarily free-roaming domestic cats were examined for the presence of sarcocysts. Serum from cats in this group and another group of 50 free-roaming cats were evaluated for the presence of S. neurona antibody. Sarcocysts were found in five of 50 (10%) cats, and S. neurona antibody in five of 100 (5%) cats. Morphological, molecular (including ribosomal RNA genes), and biological characterisation of these sarcocysts showed that they were not S. neurona or S. neurona-like. Sarcocysts found in the cats were identified morphologically as Sarcocystis felis, a common parasite of wild felids. The life cycle of S. felis is not known, and prior to this study, no molecular marker for S. felis existed. Although cats were found to be infected with S. felis sarcocysts, serological data provided evidence of possible infection with S. neurona as well. Further work is needed to determine the role of the domestic cat in the life cycle of S. neurona.

Prevalence and site specificity of Sarcocystis greineri sarcocysts in Virginia opossum (Didelphis virginiana) in Florida.

Sarcocysts of Sarcocystis greineri in the Virginia opossum (Didelphis virginiana) were observed for documenting sarcocyst prevalence, seasonal prevalence, and muscle specificity. Characteristics of sarcocysts found in striated muscle were recorded, as were light microscopy measurements. Overall prevalence of sarcocysts in striated muscle was 10.0% (24/240). No statistical difference (P = 0.156) in prevalence was detected between summer (13.1%; 16/122) and fall (6.7%; 8/118). Sarcocysts were found in muscles of the diaphragm, leg, breast, tongue, back, and esophagus. Diaphragm had the highest specificity of 72.7% (8/11), which was significantly different (P = 0.05) when compared with tongue and esophagus at 16.6% (1/6). Breast and leg muscle had a specificity of sarcocysts of 54.5% (6/11), whereas 27.2% (3/11) of back muscles contained sarcocysts.

Prevalence of sarcocysts in Florida black bears (Ursus americanus floridanus).

Sections of muscle from Florida black bears (Ursus americanus floridanus) collected in the state of Florida were observed for the presence of Sarcocystis sp. sarcocysts. Two of 132 (1.5%) black bears had muscle sections containing sarcocysts. One sarcocyst was observed per muscle section. The sarcocysts averaged 181.5 x 99.0 microm by light microscopy of hematoxylin and eosin-stained sections.

Prevalence of Sarcocystis sarcocysts in nine-banded armadillos (Dasypus novemcinctus) from Florida.

The prevalence and identity of Sarcocystis spp. sarcocysts in the skeletal muscles of nine-banded armadillos (Dasypus novemcinctus) collected from Alachua County, FL, were determined. H & E stained sections of skeletal muscle from tongue and thigh were examined. Thirty nine of 63 (61.9%) armadillos examined contained Sarcocystis sarcocysts. Two species were identified, Sarcocystis dasypi and Sarcocystis diminuta. Sarcocystis dasypi sarcocysts were found in 38 of 63 (60.3%) and S. diminuta sarcocysts were found in 6 of 63 (9.5%). Sarcocysts of S. dasypi were larger, more densely packed with bradyzoites, and bradyzoites contained within the sarcocyst were smaller than those of S. diminuta. Mixed infections occurred in 5 of 63 (7.9%) armadillos examined.

Neurologic disease in gamma-interferon gene knockout mice caused by Sarcocystis neurona sporocysts collected from opossums fed armadillo muscle.

Fifteen gamma-interferon gene knockout mice were each orally inoculated with 5 x 10(3) Sarcocystis sporocysts derived from Virginia opossums (Didelphis virginiana) fed nine-banded armadillo (Dasypus novemcinctus) muscle containing sarcocysts. Three mice were inoculated with similarly obtained homogenates, but in which no sporocysts were detected. Mouse M8 was pregnant when inoculated and gave birth during the trial. Fifteen of 15 (100%) mice inoculated with sporocysts developed neurologic signs and/or died by day 30 d.p.i. One of 3 (33.3%) mice inoculated with homogenates in which no sporocysts were detected developed clinical signs and died at 34 d.p.i. All young of mouse M8 had maternally acquired antibodies to Sarcocystis neurona, but none developed clinical neurologic signs or had protozoal parasites in their tissues. All brains from mice that developed clinical signs contained merozoites that reacted positively to S. neurona antibodies using immunohistochemical techniques. Evidence from this study further supports the nine-banded armadillo being an intermediate host of S. neurona.

Tapeworm identification in the fat sand rat (Psammomys obesus obesus).

The identification of a tapeworm (Rodentolepis nana, formerly named Hymenolepis nana) infection in a research breeding colony of sand rats (Psammomys obesus obesus) was complicated because of the unexpected long length (< 150 mm) of the worms. Other morphologic features that were consistent with this identification included the number (24), size (16 mm), and shape of the hooks on the rostellum. No evidence of intermediate hosts was found in the colony. Previous surveys of natural populations of sand rats had not identified this tapeworm. However, a detailed search of the literature revealed that variation in the size of R. nana had been reported, thus supporting the final identification of the tapeworm. R. nana is important and interesting because of its zoonotic potential and because it is the only tapeworm that is able to infect its definitive host without use of an intermediate host. This report is presented to help clarify the ambiguity found in the laboratory animal literature about the differences in the size of R. nana among rodent species used in research.

The striped skunk (Mephitis mephitis) is an intermediate host for Sarcocystis neurona.

Striped skunks, initially negative for antibodies to Sarcocystis neurona, formed sarcocysts in skeletal muscles after inoculation with S. neurona sporocysts collected from a naturally infected Virginia opossum (Didelphis virginiana). Skunks developed antibodies to S. neurona by immunoblot and muscles containing sarcocysts were fed to laboratory-reared opossums which then shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0 x 7.5 microm and each contained four sporozoites and a residuum. Sarcocysts from skunks and sporocysts from opossums fed infected skunk muscle were identified as S. neurona using PCR and DNA sequence analysis. A 2-month-old, S. neurona-naive pony foal was orally inoculated with 5 x 10(5) sporocysts. Commercial immunoblot for antibodies to S. neurona performed using CSF collected from the inoculated pony was low positive at 4 weeks p.i., positive at 6 weeks p.i., and strong positive at 8 weeks p.i. Gamma-interferon gene knockout mice inoculated with skunk/opossum derived sporocysts developed serum antibodies to S. neurona and clinical neurologic disease. Merozoites of S. neurona present in the lung, cerebrum, and cerebellum of mice were detected by immunohistochemistry using polyclonal antibodies to S. neurona. Based on the results of this study, the striped skunk is an intermediate host of S. neurona.

Seasonal and age-related changes in blood parasite prevalence in Dark-eyed Juncos (Junco hyemalis, Aves, Passeriformes).

We determined seasonal changes in blood parasite infections in a free-living population of Dark-eyed Juncos (Junco hyemalis) breeding in interior Alaska (65 degrees N; 148 degrees W). The common parasites found in blood smears were Leucocytozoon fringillinarum (56%), Trypanosoma avium (33%), and Haemoproteus fringillae (9%). In males, parasite prevalences were relatively high at arrival on breeding grounds and increased during the breeding season. Intensity of infection with Leucocytozoon also increased between spring and summer, and then decreased at the time of migration (September). This decrease did not occur in adult females. Elevated prevalences during the breeding season probably reflected the addition of new cases via vector activity to positive status resulting from spring relapse. We observed neither an association between parasite species nor a consistent relationship between parasite intensity and body condition. To further study relationships between reproductive system activity and parasite infections, we compared prevalences in adult males that were undergoing their first cycle of gonadal development and regression (males in their second calendar year, or SY) with those of older males (males in their third or more calendar year, i.e., after-second-year males or ASY). Circulating testosterone concentrations declined in both groups between arrival on breeding grounds (end of April-early May) and the end of the reproductive period (July), and they were higher in May in ASY than in SY males. At the peak of the breeding season (June), ASY males also had a higher parasite prevalence than SY males. This difference may have resulted from immunosuppressive effects of gonadal hormones and/or from behavioral differences between SY and ASY males such that older males were exposed to more insect vectors than younger males. .

The nine-banded armadillo (Dasypus novemcinctus) is naturally infected with Sarcocystis neurona.

Sarcocysts were dissected from the tongue of a nine-banded armadillo (Dasypus novemcinctus). DNA was extracted and characterised by PCR amplification followed by restriction fragment length polymorphism analysis and nucleotide sequencing. A total of 1879 nucleotides were compared; the sarcocyst DNA sequence was identical to that reported for Sarcocystis neurona. DNA was extracted from the sarcocysts of five more nine-banded armadillos. A 254-nucleotide sequence was determined for each and found to be identical to S. neurona. Western blot techniques for detection of anti-S. neurona antibody were developed for use with armadillo plasma and samples from 19 wild-caught and 17 captive-raised armadillos were examined. Whereas all of the 19 wild-caught armadillos had antibodies to S. neurona, only one of 17 captive-raised armadillos did. These results suggest that the nine-banded armadillo are naturally infected with S. neurona.

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host for Sarcocystis neurona.

The nine-banded armadillo (Dasypus novemcinctus) is an intermediate host of at least three species of Sarcocystis, Sarcocystis dasypi, Sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. Following feeding of armadillo muscles containing sarcocysts to the Virginia opossum (Didelphis virginiana), the opossums shed sporulated Sarcocystis sporocysts in their faeces. Mean dimensions for sporocysts were 11.0x7.5 microm and each contained four sporozoites and a residual body. Sporocysts were identified as Sarcocystis neurona using PCR and DNA sequencing. A 2-month-old foal that was negative for S. neurona antibodies in the CSF was orally inoculated with 5x10(5) sporocysts. At 4 weeks post-infection, the foal had a 'low positive' result by immunoblot for CSF antibodies to S. neurona and by week 6 had a 'strong positive' CSF result and developed an abnormal gait with proprioceptive deficits and ataxia in all four limbs. Based on the results of this study, the nine-banded armadillo is an intermediate host of S. neurona.

Interspecific variability of prevalence in blood parasites of adult passerine birds during the breeding season in Alaska.

Blood parasite prevalence based on microscopic examination of stained blood smears was determined in adults of 11 passerine bird species sampled during their breeding season (May and June 1997-98) in interior Alaska (USA). These species included primarily Nearctic migratory species such as the dark-eyed junco (Junco hyemalis) and neotropical migratory species such as the blackpoll warbler (Dendroica striata), alder flycatcher (Empidonax alnorum), Swainson's thrush (Catharus ustulatus), northern waterthrush (Seiurus noveboracensis), and bank swallow (Riparia riparia) as well as one long-distance palearctic migrant, the arctic warbler (Phylloscopus borealis). The more prevalent parasites were Leucocytozoon dubreuili (73% of the sampled turdinids), L. fringillinarum (42% of the sampled fringillids and parulids), and Trypanosoma avium (39% of the sampled hosts). Other parasites (H. fallisi: 18% of the sampled turdinids; Haemoproteus paruli: 14% of the sampled parulids; H. fringillae: 5% of the sampled fringillids; microfilariae: 4% of the sampled hosts) were observed less frequently. Plasmodium vaughani was found only in two yellow warblers (Dendroica petechia). Overall parasite prevalence varied between 0% in the alder flycatcher to >80% in Swainson's thrush, arctic warbler, and Townsend's warbler (Dendroica townsendi). Prevalence of various hematozoa also was bird species-dependent. No relationship was observed between prevalence and either foraging (aerial versus trees/shrubs) or nesting habits (ground versus arboreal) or general location of the wintering area of the different species examined. Prevalence also was unrelated to average dates of arrival on breeding grounds and, therefore, to potential duration of exposure to local insect vectors before capture. Differences in blood parasite prevalence among species breeding in a same region and in the same type of habitat may result from differences in host specificity such as immunological resistance to infection or blood meal preference by potential vectors and/or in behavioral adjustments/physiological traits that alter exposure to vectors.