Prevalence and genetic characterization of Echinococcus spp. in cattle, sheep, and swine in Hungary

A study was conducted to investigate genetic diversity of Echinococcus isolates collected in Hungarian slaughterhouses between 2015 and 2018. Organs of 219 animals with suspected hydatidosis were collected during routine meat inspection and sent to our laboratory. Echinococcus infection was confirmed in 65 animals. These results indicate that prevalence data based on reporting of slaughterhouses are not reliable without the appropriate training of the people responsible for meat inspection. The genetic diversity was evaluated by the DNA sequence analysis of the cytochrome c oxydase subunit 1 (cox1) mitochondrial gene. Echinococcus intermedius (n = 31), Echinococcus granulosus s.s. (n = 2), and Echinococcus multilocularis (n = 3) was identified in swine. In cattle, only E. granulosus s.s. (n = 20) was detected. E. granulosus s.s. (n = 7) was the dominant species in sheep; nevertheless, E. intermedius was also identified in two animals. E. granulosus s.s. (n = 29) and E. intermedius (n = 33) were classified in 13 and three haplotypes, respectively. The genetic diversity and haplotype network of E. granulosus s.s. were similar to that observed in some other countries of Eastern Europe. The genetic diversity of E. intermedius was low with a single dominant haplotype. Cysts were fertile in nine sheep (100%), 22 swine (61%), and three cattle (15%) indicating that all three species play a role in some extent in the epidemiology of cystic echinococcosis in Hungary. Based on the number of animals killed in the slaughterhouses involved in the present study, the rate of infection was 0.013% in sheep, 0.007% in cattle, and 0.001% in swine. As animals with hydatidosis originated from family farms, control programs should mainly focus on these facilities.

Environmental determinants of the spatial distribution of Mesocestoides spp. and sensitivity of flotation method for the diagnosis of mesocestoidosis

Mesocestoides spp. are zoonotic cestodes of wild and domesticated carnivores. Although the adult stages are relatively harmless intestinal parasites, the metacestode stages (tetrathyridia) can be responsible for life-threatening peritonitis and pleuritis in several species including dogs, cats, non-human primates and probably man. The aim of the present study was to reveal the spatial distribution pattern of Mesocestoides spp. in the most important final hosts, red foxes (Vulpes vulpes), to analyse the relationship of these patterns with landscape and climate by geographical information systems and to evaluate faecal flotation method for the detection of infection in the final host. Fox carcasses, representing 0.5% of the total fox population were randomly selected out of all the foxes of Hungary. The intestinal tract was examined by sedimentation and counting technique. The sensitivity of the flotation method was evaluated by the testing of the faecal samples of 180 foxes infected with Mesocestoides spp. The prevalence of infection was high in foxes (45.8%; 95% CI=41.0-50.6%), and the parasite was detected in all areas of Hungary. The high prevalence of the parasite in foxes suggests that the infection might also be common in outdoor dogs and cats. Mesocestoides infection could not be detected in any of the foxes by flotation method indicating that the sensitivity of the method is less than 0.6%. Therefore, almost all canine and feline infections remain undetected in the veterinary practice. Based on the statistical analysis, the altitude was the only determinant of the spatial distribution of Mesocestoides spp. indicating that infections in carnivores including dogs and cats can be expected mainly in midland regions (150-750 m above sea level). It might be attributed to the altitude-dependent species richness and abundance of the intermediate and final hosts of the parasite.

Environmental determinants of the spatial distribution of Trichinella britovi and Trichinella spiralis in Hungary

Trichinella spiralis and Trichinella britovi are the two most common species of the genus Trichinella persisting in the European wildlife. To investigate the spatial distribution of these Trichinella spp. and the factors influencing their circulation in Hungary, 3304 red foxes (Vulpes vulpes) and 0.29 million wild boars (Sus scrofa) were tested for Trichinella sp. infection in Hungary from 2006 to 2013. Trichinella spp. larvae from 68 (2.06%) foxes and 44 (0.015%) wild boars were identified by a multiplex PCR as T. britovi or T. spiralis. The locality of origin of foxes and wild boars were recorded in a geographic information system database. There was no correlation between environmental parameters in the home range of foxes and wild boars and the T. spiralis larval counts, but there was a positive correlation between the boundary zone of Hungary and T. spiralis infection (P<0.0001; odds ratio: 24.1). These results indicate that the distribution of T. spiralis in the Hungarian wildlife is determined by the transborder transmission of the parasite from the surrounding endemic countries. Multiple regression analysis was performed with environmental parameter values and T. britovi larval counts. Based on the statistical analysis, non-agricultural areas (forests, scrubs, herbaceous vegetation and pastures) and the mean annual temperature (P<0.0001; odds ratios: 9.53 and 0.61) were the major determinants of the spatial distribution of T. britovi in Hungary. The positive relationship with non-agricultural areas can be explained by the generalist feeding behaviour including scavenging of foxes in these areas. The negative relationship with the mean annual temperature can be attributed to the slower decomposition of wildlife carcasses favouring a longer survival of T. britovi larvae in the host carrion and to the increase of scavenging of foxes.

Dirofilaria immitis: an emerging parasite in dogs, red foxes and golden jackals in Hungary

Hungary was not considered to be a heartworm (Dirofilaria immitis) endemic country until 2007, when the first autochthonous canine infection was described. Herein we report additional autochthonous heartworm infections in two dogs (Canis familiaris), twenty red foxes (Vulpes vulpes) (n=534; prevalence: 3.7%; 95% CI=2.4-5.7%) and two golden jackals (Canis aureus) (n=27; prevalence: 7.4%; 95% CI=2.1-23.4%) coming from eight counties. The identification of the parasite was based on morphology, morphometrics and amplification of 12S rDNA followed by sequencing in all cases. Our results indicate that Hungary became a D. immitis endemic country in the past decade. The prevalence and intensity of heartworm infection in wild canids is similar to or lower than that observed in the Mediterranean countries of Europe (3.7-7.4% vs. 0.4-12.7% and 1.5 vs. 2.9-4.4 worms/animal). These findings are in line with the results of the recently developed climate based forecast model to predict the establishment of D. immitis in Hungary.

Echinococcus multilocularis and Trichinella spiralis in golden jackals (Canis aureus) of Hungary

Over the last decades the distribution area of the golden jackal (Canis aureus) has increased significantly in Europe, particularly in the Balkan Peninsula and in Central Europe. Vagrant individuals were described in many European countries. Herein, we report Echinococcus multilocularis (total worm count: 412) and Trichinella spiralis (101 larvae/g for muscles of the lower forelimb) infections in two golden jackals shot in Hungary. It is a new host record of E. multilocularis and T. spiralis in Europe and Hungary, respectively. As jackals migrate for long distances through natural ecological corridors (e.g., river valleys), they may play a significant role in the long distance spread of zoonotic parasites into non-endemic areas of Europe. Therefore, monitoring zoonotic parasites in this host species can be recommended in the European Union.

Molecular genetic comparison of Onchocerca sp. infecting dogs in Europe with other spirurid nematodes including Onchocerca lienalis

In the past 15 years, subconjunctival onchocercosis has been reported from 63 dogs in south-western United States (Arizona, California, Utah) and Southern and Central Europe (Germany, Greece, Hungary, Portugal, Switzerland). To reveal the taxonomic status of the parasite responsible for these infections, fragments of the mitochondrial cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 5 (ND5) genes of three European strains of canine Onchocerca sp. and the 16S ribosomal RNA (16S rRNA) gene of their Wolbachia endosymbionts were sequenced and compared to the homologous sequences of other spirurid nematodes. The evolutionary divergence between COI and ND5 gene sequences of Greek, Hungarian and Portuguese strains of canine Onchocerca sp. were similar in magnitude to that seen within Thelazia callipaeda or Onchocerca lienalis. The evolutionary divergence between the sequences of canine Onchocerca sp. and other Onchocerca spp. including O. lienalis were similar or higher in magnitude to that seen between other Onchocerca spp. The results of the current and earlier phylogenetic analyses indicate that canine Onchocerca sp. separated from other Onchocerca spp. early in the evolution. Based on the similar clinical pictures, the identical morphology of nematodes and the sequence analyses of COI and ND5 genes of the worms and 16S rRNA gene of their wolbachiae, the Onchocerca worms isolated from European dogs appear to belong to the same species. The results support the earlier biological and morphological arguments that a distinct species, most likely O. lupi originally described from the subconjunctival tissues of a Caucasian wolf is responsible for canine ocular onchocercosis in Europe.

Temporal distribution of Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna in Hungary

A survey was carried out over a 4-year period to describe the temporal distribution of three 'anthropophilic' tick species, Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna in Hungary. Altogether 4658 adult ticks belonging to the three species were collected from 1931 red foxes (Vulpes vulpes) killed in an area of about 70,000 km(2) representing all major climatic areas of the country. The seasonal activity of the three species was different. I. ricinus ticks were most active between April and June with an activity peak in May. A less marked increase of activity was also observed in September and October. The highest activity of D. reticulatus ticks was seen between September and November with an activity peak in October, nevertheless, a marked increase of activity could also be observed in April. Small number of I. ricinus and D. reticulatus were collected in all other months. H. concinna ticks were active from May to July with an activity peak in June and completely disappeared between October and March. The temporal distribution of the three tick species might be used for predictions on the seasonality of tick-borne diseases in Hungary.

Rickettsiae of the spotted-fever group in ixodid ticks from Hungary: identification of a new genotype ('Candidatus Rickettsia kotlanii')

Three common European 'anthrophilic' ticks, Ixodes ricinus, Haemaphysalis concinna and Dermacentor reticulatus, were collected in Hungary and tested, in assays based on nested PCR, for rickettsiae of the spotted-fever group. Low percentages of I. ricinus (2.7%) and H. concinna (1.0%) and a high percentage of D. reticulatus (26.8%) were found to be infected. The rickettsiae in the ticks were then identified, by sequencing of the genes coding for 16S ribosomal RNA (16S rDNA), citrate synthase (gltA) and the rOmpA outer-membrane protein (ompA), as Rickettsia helvetica, Rickettsia monacensis, Rickettsia sp. RpA4, or what is probably a newly recognized Rickettsia species ('Candidatus Rickettsia kotlanii'). These results raise the possibility that rickettsiae other than Rickettsia slovaca are involved in human disease in Hungary. Current knowledge on the distributions of the rickettsiae of the spotted-fever group that are emerging in Europe is also summarized.

Spatial distribution of Dermacentor reticulatus and Ixodes ricinus in Hungary: evidence for change?

A survey was conducted to investigate the spatial distribution of Ixodes ricinus and Dermacentor reticulatus in Hungary and to compare these data with the results of a previous large-scale survey. In the survey conducted in the 1950s, D. reticulatus adults were detected in two isolated areas of two counties, and the presence of these ticks in the collection was explained by accidental introduction. In the present survey, D. reticulatus became the second most common species occurring in all 16 counties involved in the monitoring and showed high prevalence. The change in the spatial distribution of this tick species, the increase of incidence of Babesia canis infection in Hungary, and the increasing number of canine babesiosis case reports from other Central and Central Eastern European countries since the 1970s suggest an expansion of the geographic range of D. reticulatus and intensification of the transmission rate of B. canis and probably other D. reticulatus-borne diseases (e.g. tularemia and tick-borne lymphadenopathy) in the region. The spatial distribution of I. ricinus was roughly in line with the results of the earlier survey. I. ricinus was the most common tick species being present in all 16 counties with the highest prevalence. Nevertheless, the comparison of the data of the previous and current survey cannot be used for fine-scale analysis; thus, it cannot be dismissed that the spatial distribution of I. ricinus also changed during the past decades. The spatial distribution patterns of tick-borne encephalitis in Hungary and other Central Eastern European countries may indicate such a change.

Anaplasma phagocytophilum: an emerging tick-borne pathogen in Hungary and Central Eastern Europe

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophila, Ehrlichia equi and Anaplasma phagocytophila) is the causative agent of granulocytic ehrlichiosis (anaplasmosis) in humans, horses, sheep, cattle, dogs and cats. In the present study, 452 European sheep ticks (Ixodes ricinus) collected from 100 red foxes (Vulpes vulpes) in Hungary were tested for the pathogen, as 112 pools each containing five or fewer ticks from one fox. Six of the pools, representing ticks from six different foxes, were found infected in the PCR-based test employed. This is the first time that A. phagocytophilum has been reported in Hungary. A summary of the information available from Central Eastern Europe on the prevalence of A. phagocytophilum in ticks, its seroprevalence in humans, and the number of human cases of granulocytic ehrlichiosis known in the region is presented.

Extraintestinal nematode infections of red foxes (Vulpes vulpes) in Hungary

A survey was carried out to investigate the prevalence and worm burden of extraintestinal nematodes in 100 red foxes (Vulpes vulpes) of Hungary. The overall prevalence of nematode infections of the respiratory tract was 76%. Eucoleus aerophilus (Capillaria aerophila) was the predominant species (66%), followed by Crenosoma vulpis (24%), Eucoleus (Capillaria) böhmi (8%) and Angiostrongylus vasorum (5%). Pearsonema (Capillaria) plica was found in 52% of the urinary bladders. In 3% of the foxes, Trichinella britovi was present in muscle samples. The high prevalence of lungworms and P. plica and the fox colonisation in urban areas may enhance the prevalence of these nematode infections in domestic dogs and cats, and the flow of T. britovi from the sylvatic cycle to the domestic cycle, enhancing the risk of infections in humans.

Ectoparasite infestations of red foxes (Vulpes vulpes) in Hungary

A survey was carried out to investigate the ectoparasite infestations of 100 red foxes (Vulpes vulpes) in Hungary. The overall prevalence of flea and tick infestation was high (62 and 86% with the dominance of the anthropophil Pulex irritans and Ixodes ricinus), but the number of parasites was low to moderate. Felicola vulpis was not found in the present study, and the prevalence of Otodectes cynotis was only 2%. Based on prevalence (21%), mange lesion scores, and the negative correlation between lesion scores and condition of foxes, Sarcoptes infestation should be considered as the most important parasitosis of foxes in Hungary. Besides the ecological significance of these parasites, the high overall prevalence of mange and anthropophil flea and tick infestations of foxes and the appearance of these animals in the synanthropic environment as a result of the increasing population size, may result in the increasing incidence of flea, tick and accidental mite infestation of man and domestic animals, and may enhance the transmission rate of some vector-borne diseases.

Characterization of Cryptosporidium spp.--recent developments and future needs

Cryptosporidia, widely distributed protozoan parasites of vertebrates have recently attracted increasing interest due to several serious waterborne outbreaks, the life-threatening nature of infection in immunocompromised patients, and the realization of economic losses caused by these pathogens in livestock. Genetic polymorphism within Cryptosporidium spp. is being detected at a continuously growing rate, owing to the widespread use of modern molecular techniques. The aim of this paper is to review the current status of taxonomy, genotyping, molecular phylogeny, and characterization of cryptosporidia, and to highlight the need for polyphasic typing, i.e. an integrated approach comprising standardized morphologic, biologic, and molecular methods for describing Cryptosporidium species and isolates, and for establishing "virtual" reference strains.

Molecular phylogenetic analysis of Onchocerca lupi and its Wolbachia endosymbiont

The morphology of Onchocerca lupi, responsible for canine ocular onchocercosis, is unique within the genus. Earlier analyses of the 5S ribosomal RNA gene spacer region sequence of the parasite and the 16S ribosomal RNA gene sequence of its Wolbachia endosymbiotic bacteria (Rickettsiales) supported the morphological and biological arguments that O. lupi is a distinct species. However, the exact phylogenetic position of O. lupi and its endosymbiont could not be unambiguously determined. Herein we report analyses based on the mitochondrial cytochrome oxidase I (COI) gene of the filarial species and the Wolbachia surface protein (wsp) and the bacterial cell-cycle ftsZ genes of their wolbachiae. Our results indicate that O. lupi separated from other Onchocerca spp. early in evolution. This is in line with the previous morphological analysis demonstrating that O. lupi is an atypical Onchocerca species showing both primitive and evolved characters. The phylogenetic trees generated for the COI sequences of filariae and the wsp and ftsZ sequences of their wolbachiae were congruent with each other, which supports the hypothesis that nematodes and their Wolbachia endobacteria share a long co-evolutionary history.

Ocular onchocercosis in dogs: a review

In recent decades, sporadic cases of ocular Onchocerca species infection have been reported in dogs in the USA and Europe. In the acute stage of the disease severe inflammation of the ocular and periocular tissues was observed. In chronic cases, the strongly coiled, gravid nematodes were incorporated in pea- to bean-sized granulomatous nodules in various parts of the eye, including the retrobulbar space, orbital fascia, eyelid, third palpebra, conjunctiva and sclera. Apart from the ophthalmological significance of the disease, the large number of microfilariae in the skin may be responsible for acute and chronic dermatological problems. The geographical distribution and prevalence of the infection may be greater than currently thought, because the lesions may have been erroneously regarded as other ocular diseases. Onchocerciasis is the world's second most prevalent infectious cause of blindness in human beings and parasitologists have long searched for an experimental model of human onchocerciasis; ocular onchocercosis infections in dogs may provide a useful experimental system.

Subconjunctival zoonotic onchocerciasis in man: aberrant infection with Onchocerca lupi?

In the past few decades, 10 cases of cryptic, zoonotic onchocerciasis, including two subconjunctival infections, have been reported in man. In the majority of cases, Onchocerca cervicalis, O. gutturosa or O. dewittei, which normally infect horses, cattle and wild boar, respectively, were responsible for the lesions. However, the taxonomic status of the parasites involved in the two subconjunctival infections, both of which were European, has never been unambiguously determined. In such infections, the acute phase appears to be characterized by conjunctivitis. A single, strongly coiled, immature, female worm was found incorporated in a large granulomatous nodule, in the ocular and peri-ocular tissues, in the chronic stage of each of the two eye infections. Several, patent, sporadic cases of subconjunctival O. lupi infection have recently been reported in dogs. In terms of the location of the worms, clinical signs and histopathology, these canine infections were very similar to those seen in the two human patients with eye infection. When the parasites recovered from human eyes were compared morphologically with the Onchocerca spp. infecting animals in Europe, they appeared to be most similar to O. lupi. Although O. lupi is normally a parasite of dogs, it may thus also be responsible for aberrant, zoonotic, subconjunctival infections in man.

Electron microscopic and molecular identification of Wolbachia endosymbionts from Onchocerca lupi: implications for therapy

It was recently demonstrated that Wolbachia intracellular bacteria (alpha 2 proteobacteria, Rickettsiales) living in filarial nematodes are obligatory symbionts of their hosts. Herein, we report the electron microscopic and 16S ribosomal DNA-based (16S rDNA) identification of the endobacteria harboring in Onchocerca lupi. The worm nodules containing the nematodes were removed from three Hungarian dogs naturally infected with O. lupi. Wolbachia-like endobacteria were detected by electron microscopy in the lateral chords of both adult worms and microfilariae. The endosymbionts in O. lupi resemble in location, size, and morphology the wolbachiae found in other filariae. The presence of wolbachiae in O. lupi was also confirmed by PCR amplification of the 16S rDNA of the bacteria. The 16S rDNA-based phylogenetic analysis revealed that the endosymbionts of O. lupi infecting dogs belong to the supergroup C of Wolbachia pipientis and are not identical with those of other Onchocerca spp. sequenced so far. Since intermittent treatment with oxytetracycline has adulticid and microfilaricid activity by depletion of Wolbachia endobacteria, this antibiotic treatment regimen may offer an alternative of ivermectin or diethylcarbamazine in the suppression of postoperative microfilaridermia in Onchocerca-infected dogs and may prevent relapse.

Polyphasic typing of Cryptosporidium baileyi: a suggested model for characterization of cryptosporidia

The present study was undertaken to characterize the oocyst morphology, host specificity, organ location, virulence, and sequences of the small subunit ribosomal RNA, 70-kDa heat shock protein, and oocyst wall protein genes of Cryptosporidium baileyi, and to compare this strain with other Cryptosporidium species. This study also aims to serve as a model for polyphasic (phenetic and genetic) characterization of Cryptosporidium species and strains. On the basis of these results, further genetic and phenetic characterization of an avian isolate is needed if the difference between the length or width, or both, of oocysts of an isolate and of C. baileyi is > or = 10% or if the difference between the oocyst shape index of the isolate and of C. baileyi is > or = 3% (or both). The isolate is infectious for mammals or lower vertebrates, or the host range is narrow, i.e., infectious only for some bird species; after oral or intratracheal inoculation, the parasites are not located in the cloaca and in the bursa of Fabricius or the respiratory tract; clinical disease or weight gain reduction can be observed after oral inoculation; the genetic distance for the examined gene between C. baileyi and the isolate is similar in magnitude to that observed between most closely related Cryptosporidium species.

Anticryptosporidial prophylactic efficacy of enrofloxacin and paromomycin in chickens

Two battery tests were conducted to study the anticryptosporidial prophylactic efficacy of the 2 commercially available antibiotics, enrofloxacin and paromomycin. The efficacy of enrofloxacin was 52% at the recommended level, which could not be increased, using twice the recommended dose. At the recommended levels, paromomycin reduced the oocyst output of birds by 67-82%, showing the highest efficacy of all drugs tested against avian cryptosporidiosis thus far. Moreover, the patent period was shortened by 12-23%. The body weight gain of paromomycin-treated chickens was almost identical with that of uninfected, untreated control birds irrespective of dosage, indicating the lack of toxicity. Although paromomycin is not registered for use in birds, in combination with sanitary procedures and disinfection, it may help in the control of cryptosporidiosis in some bird facilities.

Morphologic and genetic characterization of Onchocerca lupi infecting dogs

In the past decades, sporadic cases of ocular Onchocerca infection have been reported in canids in US and Europe. The present study was undertaken to provide a detailed description of the morphologic characteristics of adults and microfilariae and to characterize the 5S ribosomal rRNA gene (5S rDNA) spacer sequences of Onchocerca lupi causing canine onchocercosis. The morphology of O. lupi is unique within the genus, and morphology based cluster analysis indicates that O. lupi is not closely related to the members of domestic cattle or horse clades occurring in North America and Europe. Similarly, the signature of the 5S rDNA spacer sequences of O. lupi does not resemble any other Onchocerca 5S rDNA spacer sequences including those of the members of domestic cattle or horse clades. The adult and microfilarial morphology and sequence signature supports the biological arguments that a distinct species, O. lupi and not O. lienalis, is responsible for canine ocular onchocercosis.

Ocular onchocercosis in dogs: aberrant infection in an accidental host or lupi onchocercosis?

Four adult dogs that had spent their entire life in Hungary, were found to be infected with filaroid nematodes of the genus Onchocerca. The morphology and location of the parasites as well as pathological lesions were similar to those described earlier in the one Hungarian and five US dogs. Only moderate morphological differences were noted between the adults of Onchocerca sp. infecting dogs and O. volvulus of man or O. lienalis of cattle. Nevertheless, the morphology of microfilariae of Onchocerca from dogs is unique within the genus. Their length was less than half the length of microfilariae of other Onchocerca spp. known so far. In addition to size differences, several characteristic morphological features were observed. The unsuccessful attempt to infect dogs with O. lienalis, the absence of O. volvulus and O. lienalis in endemic regions of canine onchocercosis, the different size, morphology, and location of the adults in dogs and cattle, the exceptionally small size and unique morphology of microfilariae of Onchocerca of canids indicate that a distinct species might be responsible for canine onchocercosis. Since the larval concentration in the skin was high (50-3600 microfilariae g(-1)) in all affected dogs, the diagnosis prior to surgical removal of worm nodules can be based on the examination of a small skin snip collected from the head or abdominal region. Infections in dogs may provide a model to study human onchocercosis, therefore, further studies are encouraged on the feasibility of experimental infection of dogs with this Onchocerca species.

Canine ocular onchocercosis in Hungary

An adult male mongrel dog that had spent its entire life in Hungary, was found to have infection with filaroid nematodes of the genus Onchocerca. The gravid male and female parasites were embedded in bean-sized granulomatous masses on the conjunctiva and the sclera of both eyes. The cuticle of females consisted of two separated layers in longitudinal sections, the external layer bearing ridges and the internal layer showing striations. The ridges were marked, rounded in shape, and the ratio of body diameter to the distance between ridges varied between 7:1 and 10:1. At midbody of the worms, two striations could be seen between each pair of ridges: one under every ridge and one between neighbouring ridges. Numerous exceptionally small (96.4 microm x 6.4 microm) microfilariae were seen in the uteri of females and the surrounding tissues and isolated from skin biopsy materials. The morphology and location of the parasite and histopathological lesions of the Hungarian case were similar to that described in dogs in the United States. This case is the first documented ocular Onchocerca infection in dogs outside the western United States. Thus, onchocercosis should be considered in the differential diagnosis of ocular and periocular nodules in dogs also in Europe.

Ivermectin toxicosis in a chameleon (Chamaeleo senegalensis) infected with Foleyella furcata

Both male and female Foleyella furcata were found in the subcutaneous tissue and abdominal cavity of an adult male wild-caught Senegalese chameleon (Chamaeleo senegalensis). This nematode species is endemic to Madagascar but has never been recorded from the continent of Africa. Prior to the chameleon's death, a migrating worm was seen under the skin in the abdominal and thoracic region. Huge numbers of small, sheathed microfilariae were detected in the blood smears. The chameleon was treated with a single dose (0.2 mg/kg s.c.) of ivermectin. Serious adverse reactions (complete inertia) developed within 24 hr after injection and lasted for 7 days, indicating either ivermectin toxicity or a systemic reaction involving the release of endotoxins from the microfilariae dying in the bloodstream as a result of parasiticide therapy. Therefore, ivermectin treatment of chameleons infected with Foleyella should be avoided.

Morphologic, host specificity, and genetic characterization of a European Cryptosporidium andersoni isolate

This study was undertaken in order to characterize a Cryptosporidium muris-like parasite isolated from cattle in Hungary and to compare this strain with other Cryptosporidium species. To date, the large-type oocysts isolated from cattle were considered as C. muris described from several mammals. The size, form, and structure of the oocysts of the Hungarian strain were identical with those described by others from cattle. An apparent difference between the morphometric data of C. muris-like parasites isolated from cattle or other mammals was noted, which is similar in magnitude to the differences between Cryptosporidium meleagridis and Cryptosporidium felis or between Cryptosporidium serpentis and Cryptosporidium baileyi. The cross-transmission experiments confirmed the findings of others, as C. muris-like oocysts isolated from cattle fail to infect other mammals. The sequence of the variable region of small subunit (SSU) rRNA gene of the strain was 100% identical with that of the U.S. Cryptosporidium andersoni and C. andersoni-like isolates from cattle. The difference between the SSU rRNA sequence of bovine strains and C. muris is similar in magnitude to the differences between C. meleagridis and Cryptosporidium parvum anthroponotic genotype or between Cryptosporidium wrairi and C. parvum zoonotic genotype. Our findings confirm that the Cryptosporidium species responsible for abomasal cryptosporidiosis and economic losses in the cattle industry should be considered a distinct species, C. andersoni Lindsay, Upton, Owens, Morgan, Mead, and Blagburn, 2000.

Influence of in ovo administered Cryptosporidium baileyi oocyst extract on the course of homologous infection

In order to evaluate the effect of in ovo vaccination on avian cryptosporidiosis, two doses (1 and 10microg) of Cryptosporidium baileyi oocyst extract (OE) were injected into the amnionic sac of embryonated, specific pathogen-free chicken eggs. After hatching these birds as well as infected controls (IC) were inoculated with 8x10(5) C. baileyi oocysts at 10 days of age. Another group of chickens remained uninfected (UC). Faecal oocyst shedding was measured every second day, and weekly ELISAs were performed to monitor seroconversion. Those chickens that received OE during embryogenesis showed dose-dependent shift in their oocyst shedding, with higher oocyst output of OE1 and OE10 birds compared to IC ones. The patency was significantly longer in the OE10 group than in IC or OE1. ELISA results showed low seroconversion of OE1 and OE10 chickens prior to homologous challenge. Challenge infection resulted in antibody levels without significant difference between IC, OE1 and OE10 groups. These data suggest that in ovo vaccination with C. baileyi oocyst extract does not promote immune response, moreover, it may impair immunity and thus delay the clearance of cryptosporidia from chickens.

Morphologic, host specificity, and molecular characterization of a Hungarian Cryptosporidium meleagridis isolate

This study was undertaken in order to characterize Cryptosporidium meleagridis isolated from a turkey in Hungary and to compare the morphologies, host specificities, organ locations, and small-subunit RNA (SSU rRNA) gene sequences of this organism and other Cryptosporidium species. The phenotypic differences between C. meleagridis and Cryptosporidium parvum Hungarian calf isolate (zoonotic genotype) oocysts were small, although they were statistically significant. Oocysts of C. meleagridis were successfully passaged in turkeys and were transmitted from turkeys to immunosuppressed mice and from mice to chickens. The location of C. meleagridis was the small intestine, like the location of C. parvum. A comparison of sequence data for the variable region of the SSU rRNA gene of C. meleagridis isolated from turkeys with other Cryptosporidium sequence data in the GenBank database revealed that the Hungarian C. meleagridis sequence is identical to a C. meleagridis sequence recently described for a North Carolina isolate. Thus, C. meleagridis is a distinct species that occurs worldwide and has a broad host range, like the C. parvum zoonotic strain (also called the calf or bovine strain) and Cryptosporidium felis. Because birds are susceptible to C. meleagridis and to some zoonotic strains of C. parvum, these animals may play an active role in contamination of surface waters not only with Cryptosporidium baileyi but also with C. parvum-like parasites.

Attempted chemoprophylaxis of cryptosporidiosis in chickens, using diclazuril, toltrazuril, or garlic extract

Three battery tests were conducted to study the anticryptosporidial efficacy of the 2 commercially available anticoccidial triazinone derivates, diclazuril and toltrazuril, and a garlic extract. At the recommended level, diclazuril reduced the oocyst output of birds by 14.6%. The efficacy of toltrazuril was 52.1% at the recommended level, which could be moderately increased using 5 or 10 times the recommended dose. However, these doses resulted in significant weight gain reduction. The efficacy of garlic extract was 24.4%. It is concluded that none of the drugs can be recommended for chemoprophylaxis or therapy of cryptosporidiosis in chickens.

Study on the course of Cryptosporidium baileyi infection in chickens treated with interleukin-1 or indomethacin

The effects exerted by human recombinant interleukin-1 beta (hrIL-1 beta) and the prostaglandin inhibitor indomethacin on the course of Cryptosporidium baileyi infection in chickens were studied. Daily oocyst shedding was monitored by a quantitative method throughout the experiment. Humoral immune response to C. baileyi was assessed by ELISA at 3 weeks of age while the level of cellular immune response to phytohaemagglutinin-P (PHA-P) by a skin test at 23 days of age. Parenteral application of hrIL-1 beta decreased oocyst shedding to 62%, but the infection ran a similar course in treated and control birds. The PHA-P skin test demonstrated increased cellular immune reaction in chickens receiving IL-1 beta, but there was no significant difference in the humoral responses of the two groups as detected by ELISA. On the other hand, indomethacin mixed to the feed lessened oocyst shedding to 13.7% and also shortened its duration. Immunological parameters as reflected by PHA-P skin test and ELISA results indicated enhanced cellular but unaltered humoral immune response. These data suggest that the systemic application of interleukin-1 can induce partial protection against C. baileyi in chickens and that prolonged, abundant oocyst shedding is due to an indomethacin-sensitive immunodepression via the prostaglandin pathway.

Immunogenicity of three oocyst extracts of Cryptosporidium baileyi in experimentally infected chickens

The immunogenic properties of water-soluble and detergent-extracted components of Cryptosporidium baileyi oocysts were studied. Oocyst cytosol antigen (OCA) containing hydrophilic proteins was obtained by freeze-thaw cycles in liquid nitrogen. This was followed by Triton X-114 extraction of remaining oocyst fragments to dissolve membrane-bound proteins (TRE). The remainder of the pellet was solubilized with sodium dodecyl sulfate and treated with 2-mercaptoethanol to reduce disulfide-linked oocyst wall proteins (BME). The immune recognition of these three extracts was evaluated during the course of experimental cryptosporidiosis in chickens using ELISA, immunoblotting, and the lymphocyte stimulation test (LST). Four groups of chickens were infected at various times with different doses of C. baileyi and one group with the mammalian parasite C. parvum. Analysis of the data revealed that OCA proteins are well recognized by serum antibodies during the infection and to a limited extent by sera from chickens infected with C. parvum. Humoral responses of chicken groups to this antigen did not correlate well with the length of patency in contrast with its cellular recognition in LST. TRE gave lower values than OCA in both ELISA and LST, though it was still specifically recognized by samples from C. baileyi-infected chickens. Antibodies reacted aspecifically with BME, since only samples of birds which were immunocompetent at the time of their infection were able to recognize this extract as antigen. Immunoblotting revealed more specific components in OCA than in TRE or BME.

Assessment of maternal immunity to Cryptosporidium baileyi in chickens

The degree of protection to Cryptosporidium baileyi in the progeny of infected chickens was studied. Hens at the beginning of their laying period were given orally three consecutive, large doses of C. baileyi oocysts at weekly intervals. The infection became patent after 6 days and lasted for another 6 days. Increasing serum IgG, and serum, bile, lachrymal and salivary IgA were demonstrated from their samples. These immunoglobulins were transferred to the eggs, since high levels of maternally derived IgG and lower amount of IgA were present in their yolks. Hatchlings of infected hens were divided into uninfected (UY) and infected (IY) groups, the birds in the latter receiving an oral inoculum of C. baileyi oocysts on the first day of their life. Two other groups, progeny of uninfected hens served as controls (uninfected UC, and infected IC). Maternal IgG was detected in serum samples of UY hatchlings which was eliminated by the third week. The total oocyst shedding of IY chickens was 54.3% lower than that of the controls (IC), however, the prepatent and patent periods did not show significant difference. In spite of the partial protection observed in IY birds, their humoral immune response to C. baileyi was significantly lower when compared to IC. A dot-ELISA was developed to evaluate seroconversion of infected chickens which was 100% in both infected groups. The findings of the present study suggest that infection of hens with C. baileyi results in partial protection of their progeny to this parasite, and factors other than immunoglobulins may also be transferred via the eggs.

Effect of F-2 and T-2 fusariotoxins on experimental Cryptosporidium baileyi infection in chickens

The course of Cryptosporidium baileyi infection in chickens fed with different doses of fusariotoxins was compared with that of control groups. F-2 toxin levels of 0.187-1.5 mg kg-1 and T-2 toxin levels of 0.187-6.0 mg kg-1 were investigated. The experimental animals were orally infected with 6 x 10(5) C. baileyi oocysts at 1 week of age. Total daily oocyst output was monitored by a quantitative method. Acquired immunity was tested at the age of 4 weeks, by ELISA and by a challenge infection with an equal number of oocysts, upon recovery from the primary infection. The results show that in chickens kept on the lower doses of F-2 and T-2 toxins, the parasite infection ran a similar course to that in the control groups, and the animals became resistant to re-infection. However, when higher doses (2.0-6.0 mg kg-1) of T-2 toxin were used, a depression of weight gain was observed with some other physiological parameters (PCV, weight of bursa, weight of thymus, skin thickness in PHA-P skin test) also indicating toxic effect and, simultaneously, the oocyst output decreased significantly and the patent period was slightly prolonged. Although certain modifications of the immune response could be revealed, the chickens became resistant to re-infection. Only early (1 week of age) parasite infection and 6 mg kg-1 T-2 toxin in the feed significantly depressed body weight gain and immunity.

Attempts to immunize chickens against Cryptosporidium baileyi with C. parvum oocysts and Paracox vaccine

To study the possibility of immunization against Cryptosporidium baileyi Current, Upton et Haynes, 1986 with the attenuated anticoccidial vaccine, Paracox and oocysts of C. parvum Tyzzer, 1912, chickens were inoculated orally with either 3 x 10(3) vaccine oocysts or 8 x 10(5) C. baileyi or C. parvum oocysts at 1 week of age. The inoculation with Paracox vaccine and C. parvum oocysts was repeated at 2 and 3 weeks of age. Uninfected birds served as controls. All animals with the exception of one uninfected group were challenged orally with either 8 x 10(5) C. baileyi or 3 x 10(5) Eimeria tenella Railliet et Lucet, 1891 oocysts at 4 weeks of age. Sera were collected at 4 weeks of age, and were examined by ELISA using C. baileyi antigens. Birds inoculated with C. parvum oocysts did not shed C. parvum oocysts in their faeces, but anticryptosporidial antibodies could be detected in the sera. The total oocyst output of C. parvum inoculated chickens was 17% of that of previously uninfected birds after the oral challenge with C. baileyi. Considering that antibodies play no or only a minor role in resistance to C. baileyi, these results suggest that inoculation of chickens with C. parvum oocysts stimulated also cellular immune response. Based on the relative body weight gain, faecal scores, oocyst output, mortality, and caecal lesions in the birds immunized with Paracox vaccine and challenged with E. tenella, the vaccination induced only a moderate protection against the reinfection. The results of cross-immunization of chickens with Eimeria spp. and C. baileyi suggest that attenuated anti-eimerian vaccines do not induce any protection against cryptosporidial infection.

Attempts to immunize chickens with Cryptosporidium baileyi oocyst extract

In order to study the possibility of immunization against Cryptosporidium baileyi with extracted crude antigen, Arbor Acres chickens were injected intramuscularly with 80 micrograms of C. baileyi oocyst-derived proteins (uninfected immunized, UI) or inoculated orally with 8 x 10(5) viable C. baileyi oocysts (infected control, IC) at 1 wk of age. The immunization was repeated in the UI group at 2 wk of age. Uninfected (UC) birds served as controls. All animals in UI, IC, and UC groups were challenged orally with 8 x 10(5) C. baileyi oocysts at the age of 4 wk. Blood samples were collected when birds were 4 and 6 wk of age, and sera were examined by enzyme-linked immunosorbent assay for the presence of antibodies against C. baileyi. Total oocyst output of UI chickens was about 60% of that of UC birds after challenge, and the prepatent and patent periods were nearly identical in the latter 2 groups. In contrast, IC birds developed complete resistance to challenge infections. These results suggest that immunization with the oocyst extract of C. baileyi may confer some degree of protection against oral challenge; however, the protection is less effective than that induced by primary oral infection. The lack of significant difference between the antibody responses of IC and UI animals to C. baileyi at 2 wk of age suggests that serum antibodies play little role in acquired resistance to challenge infection.