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At least 19 recordsLinked to original sources

PubMed2005

Oocysts of Neospora caninum, Hammondia heydorni, Toxoplasma gondii and Hammondia hammondi in faeces collected from dogs in Germany.

Faecal samples of 24,089 dogs were examined coproscopically in two veterinary laboratories in Germany between March 2001 and October 2004. In 47 dogs, oocysts of 9-14 microm size were found. Their morphology was similar to those of Hammondia heydorni and Neospora caninum. Samples of 28 of these dogs were further examined by inoculation into gerbils: seven isolates induced a specific antibody response against antigens of N. caninum NC-1 tachyzoites. This response suggests that the isolates contained N. caninum. In addition to H. heydorni (12 times isolated), Toxoplasma gondii occysts (twice) and Hammondia hammondi oocysts (twice) were observed in dog faeces. The latter findings suggest that coprophagia with a subsequent intestinal passage by dogs plays a role in the dissemination of coccidian parasites for which cats are definitive hosts. Five of the seven N. caninum (NC-GER2, NC-GER3, NC-GER4, NC-GER5, NC-GER6) and the two T. gondii isolates (TG-dgGER1, TG-dgGER2) were successfully passaged into cell culture and are now available for detailed characterization. In contrast to oocysts of other parasites, N. caninum oocysts were predominantly found between January and April (Fisher exact; P=0.038). In the sera of dogs shedding N. caninum, no reactions against the immunodominant antigens with apparent molecular weights of 19, 29, 30, 33 and 37 kDa of N. caninum tachyzoites were observed 3-5 weeks after shedding. However, the animals recognized a 152-kDa N. caninum antigen. Compared with those identified as H. heydorni, T. gondii or H. hammondi, N. caninum oocyst isolates were significantly smaller in length with the 75th percentiles <or=10.7 microm when measured in concentrated sucrose solution and smaller length-width ratios with the 75th percentiles <or=1.06. It may thus be possible to develop criteria for a preliminary identification of N. caninum in dog faeces based on the oocyst morphology.

Animals↗

PubMed1981

Protective immunity against clinical toxoplasmosis in dairy goats vaccinated with Hammondia hammondi and Hammondia heydorni.

To determine the virulence of Toxoplasma gondii, twelve 2- to 3-month-old goats were inoculated orally with 1,000 to 100,000 infective oocysts of the GT-1 strain of T gondii. Four of 4 goats inoculated with 100,000 oocysts, 4 of 4 goats inoculated with 10,000 oocysts, and 2 of 4 inoculated with 1,000 oocysts died (or became moribund) of acute toxoplasmosis 7 to 26 days after inoculation. Goats vaccinated with Hammondia hammondi or H heydorni were challenge exposed with 10,000 or 100,000 oocysts (10 or 100 median lethal doses). Four of 4 goats vaccinated with H hammondi survived after challenge exposure with 10,000 T gondii oocysts, whereas only 2 of 4 goats survived challenge exposure with 100,000 T gondii oocysts. Of 4 goats vaccinated with H heydorni, 3 died or were euthanatized 13, 14, and 26 days after challenge exposure with 10,000 T gondii oocysts. Goats vaccinated with H hammondi developed low levels of Sabin-Feldman dye test antibodies (less than or equal to 1:64) to T gondii antigen, whereas H heydorni-vaccinated goats generally remained seronegative. The results indicate that goats may be a model to investigate immune protection after vaccination with H hammondi against clinical toxoplasmosis in animals.

Animals↗

PubMed2003

A Hammondia-like parasite from the European fox (Vulpes vulpes) forms biologically viable tissue cysts in cell culture.

Tissue cysts of parasites of the genus Hammondia are rarely described in naturally or experimentally infected intermediate hosts. However, ultrastructural examinations on tissue cyst stages of Hammondia sp. are needed, e.g. to compare these stages with those of Neospora caninum and other related parasites. We describe a cell culture system employed to examine the in vitro development of tissue cysts of a Hammondia sp.-like parasite (isolate FOX 2000/1) which uses the European fox as a definitive host. Cells of a diploid finite cell line from embryonal bovine heart (KH-R; CCLV, RIE 090) were infected by inoculation of sporozoites und cultivated for up to 3 months. Transmission electron microscopic examination of 17 day old cell culture material revealed the presence of cyst walls. Infected cell cultures cultivated for 2 months were used to feed a fox. Six to 13 days post infection the fox shed large numbers (n=1.2 x 10(7)) of Hammondia-sp. like oocysts which could not be distinguished from those used to infect the cell culture as determined by DNA sequencing of the internal transcribed spacer 1 and the D2/D3 domain of the large subunit ribosomal DNA. To find out the proportion of parasitophorous vacuoles that had developed into tissue cysts, the expression of bradyzoite markers was examined by probing infected cell cultures with mouse polyclonal antibodies against Toxoplasma gondii bradyzoite antigen 1 (anti-BAG1) and rat monoclonal antibodies against a cyst wall protein (mAbCC2). Nineteen and 90 days post infection all parasitophorous vacuoles in the cell cultures were positive with anti-BAG1 and mAbCC2. This shows that biologically viable (i.e. infectious) tissue cysts of a fox-derived Hammondia sp. isolate (FOX 2000/1) can be efficiently produced in this cell culture system. Since in vitro cystogenesis of dog-derived Hammondia heydorni has not been observed yet, in vitro cyst formation might be one trait to separate fox-derived Hammondia sp. from H. heydorni on a species level.

Animals↗

PubMed2026

Canine cholecystitis in the presence of Hammondia spp. infection.

Biliary protozoal infections are becoming increasingly recognized in dogs. Sarcocystidae protozoal infections (i.e Toxoplasma, Neospora, Hammondia, Besnoitia, and Sarcocystis spp.) are uncommon and host-specific. Diagnosis is traditionally dependent on tissue or serologic evaluation; sensitivity and specificity for these techniques can vary. PCR amplification and genetic sequencing provide a technique to expedite diagnosis and species identification in clinical biliary protozoal infections. Bile samples were collected percutaneously from two dogs presented to a referral hospital with mixed hepatopathies and hyperbilirubinemia. Diagnostic imaging revealed changes consistent with hepatobiliary inflammation, and tachyzoites were identified via bile cytology. Sera were positive for anti-Toxoplasma sp. (n = 1/2) and anti-Neospora sp. (n = 2/2) antibodies. Genomic isolation from bile and pan-Sarcocystidae (18S rRNA) PCR amplification were consistent with Hammondia spp. Additional 28S rRNA (LSU), alpha-tubulin (aTUB) and cytochrome b (CytB) gene-specific fragments were PCR amplified and sequenced. Phylogenetic analysis of LSU DNA fragment (584 bp) suggested both patients were infected with Hammondia spp. closely related to H. heydorni. Sequencing of aTUB (234 bp) and CytB (344 bp) revealed Patient 1 Hammondia spp. was more closely related to H. triffittae, while Patient 2 was more similar to H. heydorni. Treatment with clindamycin, and in one case additional enrofloxacin, resolved clinical and clinicopathologic changes in both dogs. This report highlights the importance of multilocus sequencing in protozoal identification in atypical infections, clinical manifestations of canine hepatobiliary hammondiasis, and need for regional Sarcocystidae prevalence studies.

Animals↗

PubMed1982

A Hammondia-like coccidian with a mink-muskrat life cycle.

A tissue cyst-forming coccidian morphologically resembling the known species Hammondia has a mink-muskrat life cycle. Cysts are found in skeletal muscle of muskrats (Ondatra zibetheca). Mink (Mustela vison) fed infected muskrat carcasses shed oocysts for 4 to 6 days after a prepatent period of 6 to 8 days. The oocysts, 99% of which are unsporulated in mink feces, measure 11.5 to 12 microns X 10 to 11 microns. Sporulated oocysts have 2 sporocysts, each with 4 sporozoites. The present work was insufficient to establish whether this Hammondia-like parasite is identical to the known Hammondia spp. or is a new parasite, although the evidence gathered supports the hypothesis that this parasite is a new member of the genus Hammondia.

Animals↗

PubMed1978

[Comparative review of the developmental biology of the genera Sarcocystis, Frenkelia, Isospora, Cystoisospora, Hammondia, Toxoplasma and Besnoitia (author's transl)].

A review is given of the advances in our knowledge of the developmental biology of the so-called cyst-forming coccidia in the years from 1974 to 1978. Until 1970 only 6 Isospora species were known to occur in cats, dogs and men. After the discovery of the coccidian nature of the genera Toxoplasma, Sarcocystis, Besnoitia and Frenkelia, and after the discovery of the new genus Hammondia the number of known species rose to over 30. In addition it could be shown that also birds of prey, owls and reptiles serve as final hosts for several Sarcocystis and Frenkelia species. The coccidia with isosporoid oocysts can be classified into two major groups: Species with gamogony and sporogony in the final host (Sarcocystis, Frenkelia) and species with schizogony and gamogony in the final host and sporogony on the ground (Isospora, Cystoisospora, Hammondia, Toxoplasma, Besnoitia). The subdivision of the first group into the genera Sarcocystis and Frenkelia based on the localization of their cysts in the musculature and in the brain, respectively, cannot be upheld in the future. Their classification into organisms with small cystozoites of about 7 microm with birds or reptiles as final hosts (Sarcocystis and Frenkelia species of rodents) and those with large cystozoites of about 15 microm and mammals as final hosts (Sarcocystis spp. of domestic animals and rodents) would be more significative. The second group can be subdivided into monoxenous species (Isospora), species with an optional intermediate host in which no or only slight multiplication occurs (Cystoisospora) and in genera with a multiplication in two phases in the intermediate host (Hammondia, Toxoplasma, Besnoitia). The nomenclature of single species is very controversial. As an example the controversial apprehension of the taxonomy of the Sarcocystis species of cattle is discussed. An application has been submitted to the International Commission for the Zoological Nomenclature to delcare a number of names as nomina dubia and to introduce unambiguous names for those organisms for which type specimens are available.

Animals↗

PubMed1999

Phylogenetic analysis based on full-length large subunit ribosomal RNA gene sequence comparison reveals that Neospora caninum is more closely related to Hammondia heydorni than to Toxoplasma gondii.

Since its first description in the late 1980s, Neospora caninum has been recognised as a prominent tissue cyst-forming parasite due to its ability to induce congenital disease and abortion in animals, especially cattle. It is found worldwide and is a cause of significant economic losses for the livestock industry. However, its place within the family Sarcocystidae, like that of several other taxa, remains unresolved. Neospora caninum shares several morphological and life cycle characters with Hammondia heydorni, although it is most commonly thought of as being a close relative of Toxoplasma gondii. This study presents information regarding the phylogenetic relationship of N. caninum to species currently classified into the genus Hammondia, as well as to two strains (RH and ME49) of T. gondii based on the full-length large subunit ribosomal RNA gene. Phylogenetic analyses using two alignment strategies and three different tree-building methods showed that the two species in the genus Hammondia are paraphyletic. Neospora caninum was shown to form a monophyletic clade with H. heydorni instead of T. gondii, which in turn was shown to be most closely related to H. hammondi. The finding that N. caninum and H. heydorni are closely related phylogenetically may aid the elucidation of currently unknown aspects of their biology and epidemiology, and suggests that H. heydorni should be considered in the differential diagnosis of N. caninum from other apicomplexan parasites.

Animals↗

PubMed1979

Serological cross-reactions between toxoplasma and hammondia.

Toxoplasma and Hammondia infected mice, dogs, rabbits, and pigs were tested for Toxoplasma antibodies by means of 5 serological methods. All Toxoplasma infected animals showed Toxoplasma-specific antibodies. Only sera of Hammondia infected mice and dogs showed positive serological reactions with Toxoplasma antigen in the SFT, CFT, and ELISA. IFAT and IHA, however, proved to be Toxoplasma-specific. The influence of Hammondia infections on the Toxoplasma serology is discussed.

Animals↗

PubMed2000

The taxonomic importance of obligate heteroxeny: distinction of Hammondia hammondi from Toxoplasma gondii--another opinion.

We enumerate identical and divergent findings concerning the obligate heteroxenous Hammondia hammondi and the facultatively homoxenous or heteroxenous Toxoplasma gondii. Differences exist in life-cycles, transmission, and host range, especially transmissibility to birds and mammals other than rodents, in ultrastructural morphology, immunity and serology in cats and to lesser degree in rodents, in DNA sequences and in isoenzymes. Because the recognition of obligate heteroxeny is essential to study these organisms and to recognize them as taxa, it is advantageous to give heteroxeny a generic rather than a specific value. Characterization of organisms with the life-cycle patterns of Hammondia, Sarcocystis, Frenkelia, and Toxoplasma is best achieved by means of the genera presently used.

Animals↗

PubMed2000

Neospora caninum: is it really different from Hammondia heydorni or is it a strain of Toxoplasma gondii? An opinion.

The published data concerning Toxoplasma gondii, Hammondia hammondi, H. heydorni and Neospora caninum on one side and between T. gondii on the other were neglected by most authors. As conclusion we are convinced that there are only two valid species: Isospora (Toxoplasma) gondii and Hammondia heydorni. The first includes as a strain H. hammondi and the latter N. caninum. In any case there is absolutely no reason (with respect to general Zoological nomenclature) to create new genera!

Animals↗

PubMed2005

Differential detection of Hammondia hammondi from Toxoplasma gondii using polymerase chain reaction.

Hammondia hammondi and Toxoplasma gondii are two related coccidian parasites, with cats as definitive hosts and warm-blooded animals as intermediate hosts. It is difficult to differentiate them by morphological and serological parameters. In the present study, primers were designed to specifically amplify the ITS-1 region of H. hammondi to differentiate it from T. gondii. Attempts were made to detect the presence of H. hammondi DNA in the tissues of mice infected with H. hammondi alone, as well as from mixed infections with T. gondii, using the newly designed primers. The de novo primers effectively amplified the H. hammondi-specific target fragment from all samples containing H. hammondi, including those with concomitant T. gondii infection. Further, the primers did not amplify any fragment from the related parasites like T. gondii, Neospora caninum and Hammondia heydorni. The new primers provide simple and efficient means to differentially diagnose H. hammondi from T. gondii even in samples containing both parasites, thus obviating the need for other labourious techniques like mouse bioassay and in vitro cultivation.

Animals↗

PubMed2003

Redescription of Hammondia hammondi and its differentiation from Toxoplasma gondii.

Hammondia hammondi is a protozoan parasite that, until 1975, was misidentified as Toxoplasma gondii. Recently, the validity of H. hammondi has been questioned. In this article, the authors redescribe the parasite and its life cycle, provide accession numbers to its specimens deposited in a museum, and distinguish it structurally and biologically from T. gondii. Hammondia hammondi was found to be structurally, biologically, and molecularly different from T. gondii.

Animals↗

PubMed1980

Hammondia heydorni infection in sheep, goats, moose, dogs and coyotes.

The transmission of Hammondia heydorni among sheep, goats, cattle, dogs and coyotes is described. Oocysts of H. heydorni, obtained from dog faeces by feeding naturally infected goat meat, were fed to an experimental goat. After 312 days tissues from this animal were fed to 2 dogs. One dog, which received goat muscle, shed oocysts, whereas the other dog which received brain, spleen, kidneys, lungs and liver did not. Oocysts from the dog fed goat muscle were fed to an experimental sheep. After 73 days sheep tissues were fed to a dog and a coyote, both of which shed oocysts 5-8 days later. A second isolate of H. heydorni was obtained by feeding naturally infected beef to a coyote. These oocysts were fed to a single goat and sheep and after 71 days, muscle from these 2 animals was fed to 2 dogs and 2 coyotes, all of which shed oocysts 5-8 days later. None of the animals inoculated with H. heydorni became ill and no Hammondia-like organisms were found in tissue sections from the herbivores. Another dog shed H. heydorni-like occysts between 7 and 10 days after ingesting naturally infected muscles from a moose. These results indicate that H. heydorni infects goats, sheep, moose and coyotes in addition to cattle and dogs.

Animal Diseases↗

PubMed1999

The genus Hammondia is paraphyletic.

The phylogenetic relationships amongst Hammondia, Neospora and Toxoplasma were investigated by DNA sequence comparisons of the D2/D3 domain of the large subunit ribosomal DNA and the internal transcribed spacer 1. The results obtained allow us to reject the hypothesis that N. caninum and H. heydorni are the same species and show that Hammondia hammondi is probably the sister taxon to Toxoplasma gondii.

Animals↗

PubMed1992

Isoenzyme analysis of Hammondia hammondi and Toxoplasma gondii sporozoites.

Isoenzyme analysis using isoelectrofocusing in polyacrylamide gels was used to distinguish Hammondia hammondi and Toxoplasma gondii sporozoites. Five enzyme systems were studied: aconitase (EC 4.2.1.3), aspartate aminotransferase (EC 2.6.1.1), glucose phosphate isomerase (EC 5.3.1.9), lactate dehydrogenase (EC 1.1.1.27), and phosphoglucomutase (EC 2.7.5.1). Three stocks of T. gondii belonging to 3 zymodemes were compared to 1 stock of H. hammondi. Hammondia hammondi differed from T. gondii at all 5 loci analyzed. This was observed for all 3 zymodemes of T. gondii. These results indicated clear genetic differences between the 2 species.

Aconitate Hydratase↗

PubMed1983

The camel (Camelus dromedarius) as an intermediate host for Hammondia heydorni.

Dogs fed raw camel meat containing two types of cysts shed unsporulated Hammondia heydorni oocysts and later sporulated Sarcocystis sporocysts in their feces, but were resistant to reinfection with the Hammondia cysts. Sporulated H. heydorni occysts did not induce an enteroepithelial cycle in dogs, but resulted in the formation of muscle cysts.

Animals↗

PubMed1981

Prevention of abortion and neonatal death due to toxoplasmosis by vaccination of goats with the nonpathogenic coccidium hammondia hammondi.

Six does serologically negative to toxoplasma gondii were vaccinated with 1 million oocysts of the nonpathogenic coccidiym Hammondia hammondi 17 to 73 days before breeding. Two does were not inoculated with H hammondi. All does were mated with a T gondii-free buck. Between the 51st and 119th days of their pregnancies, 5 of the 6 Hammondia-vaccinated does and the 2 controls were each inoculated orally with 1,000 infective oocysts of the GT-1 strain of T gondii. Four of the 5 Toxoplasma-inoculated vaccinated does gave birth to 8 apparently healthy kids at the expected gestation period. The 5th vaccinated doe gave birth to 3 kids that died during delivery or were born dead. Toxoplasma gondii was isolated in mice inoculated with tissues of all kids born to vaccinated does. The vaccinated doe which was not inoculated with T gondii gave birth to 2 healthy noninfected kids. Of the 2 control pregnant does (not vaccinated, but inoculated with T gondii), 1 aborted due to toxoplasmosis 17 days after inoculation. The other control doe had 2 dead fetuses and retained fetal membranes in uterus when necropsied at the expected parturition time. the results indicate that it might be possible to develop a vaccine against toxoplasmic abortions in animals.

Abortion, Veterinary↗

PubMed1975

Hammondia hammondi gen. nov., sp.nov., from domestic cats, a new coccidian related to Toxoplasma and Sarcocystis.

Hammondia hammondi gen.nov.,sp.nov (Eimeriorina:Sarcocystidae) is described as an obligate heteroxenous protozoon of domestic cats (final host) and laboratory mice (experimental intermediate host). Oocysts from the final host are infectious only for the intermediate host; and cysts from the intermediate host are infectious only for the final host. Intracellular cysts develop principally in striated muscle of mice that ingest oocysts, with a few cysts in the brain and perhaps elsewhere. Cysts are without septa or radial spines; bradyzoites are slender, there is no evidence of metrocytes. Cysts are not infectious for mice. After the ingestion of cysts by cats, a multiplicative cycle precedes the development of gametocytes in the epithelium of the samll intestine. Oocysts are shed unsporulated, sporogony is outside of the host, resulting in two sporocysts with four sporozoites each. Oocysts of the species average 11 x 13 mum. The prepatent period i 5s 5 to 8 days, and oocyst shedding persists for 10 to 28 days followed by immunity. Cysts in skeletal muscle measured between 100 and 340 mum in length and 40 and 95 mu-m in width. Experimental intermediate hosts are laboratory mice, rats, hamsters, guinea pigs, Peromyscus and Mastomys. Some of the intermediate hosts develop low levels of antibody and some cross-immunity against Toxoplasma; however, this has not been observed in cats.

Animals↗