Investigations into the prevention of prenatal and lactogenic Toxocara canis infections in puppies by application of moxidectin to the pregnant dog.

Aim of the investigation was to examine whether two administrations of moxidectin to pregnant dogs could prevent pre-natal and lactogenic infections of puppies with reactivated Toxocara canis larvae. Four pregnant beagles, infected experimentally with 20 000 embryonated eggs of T. canis, were treated subcutaneously with 1 mg moxidectin per kg body weight on days 40 and 55 of pregnancy (5-13 days before parturition). One further dam and its puppies served as untreated control. Two applications of moxidectin completely prevented pre-natal and lactogenic infections in the puppies. Neither intestinal stages nor somatic larvae were found in the dams or their corresponding puppies. All puppies and dams of the treatment group remained coproscopically negative until 42 days after parturition. The administration of moxidectin did not show any side effects in the dams. None of the puppies of the treated dams showed any pathological abnormalities. In the untreated dam one adult and 26 somatic larvae of T. canis were detected at necropsy. All puppies of the untreated dam showed a patent T. canis infection from day 28 post-natum (p.n.); 296 pre-adult and adult stages of T. canis were spontaneously eliminated and 51 intestinal stages and five somatic larvae of T. canis were recovered at necropsy. In contrast to the puppies of the treated dams all negative control puppies showed blood eosinophilia after parturition and elevated liver enzyme levels.

The prevalence and transmission to exotic equids (Equus quagga antiquorum, Equus przewalskii, Equus africanus) of intestinal nematodes in contaminated pasture in two wild animal parks.

Wild equids maintained in large enclosures may suffer from helminth diseases because common hygiene practices have only limited effects on parasite populations. Weekly monitoring of helminth prevalences and pasture infestation was performed for 1 yr in several extensive maintenance systems of two wildlife parks with similar climates to determine when veterinary intervention to control parasites would be useful. We also sought evidence of natural immunogenic reactions among herds of Chapman zebras (Equus quagga antiquorum), Przewalski's horses (Equus przewalskii) and dwarf donkeys (Equus asinus africanus). Fecal and vegetation samples and cultures for third-stage larvae revealed permanent egg shedding in the three species and pasture infestation during the warm, moist periods (July-September) in all enclosures. Stable social structure and low equid population density may be sufficient to make prophylaxis unnecessary in adults, whereas biotic and abiotic environmental factors such as crowding, animal transfers, social integration of subadults, and weaning stress may facilitate temporary severe infections of individuals. Biweekly helminth monitoring is a useful diagnostic tool for extensive management of exotic equids.

Investigations into the prevention of neonatal Ancylostoma caninum infections in puppies by application of moxidectin to the bitch.

The aim of this investigation was to examine whether reactivated Ancylostoma caninum larvae can be eliminated by the administration of moxidectin to pregnant bitches. Four pregnant bitches infected experimentally with 20,000 third-stage larvae of A. caninum were treated subcutaneously with 1 mg moxidectin/kg body weight on day 55 of the pregnancy (5-8 days before parturition). Another four experimentally infected pregnant bitches served as controls. The single moxidectin treatment completely prevented lactogenic infections in the puppies. Neither intestinal stages nor somatic larvae could be found. The administration of moxidectin caused no local or systemic side-effects in the bitches. All 22 puppies of the treated bitches were born healthy and remained so during the whole trial period. Beginning during the third week after birth, all 20 puppies of the untreated bitches developed a severe microcytic, hypochromic anaemia and they revealed a total of 8649 intestinal stages of A. caninum after autopsy.

Transmission trials, ITS2-PCR and RAPD-PCR show identity of Toxocara canis isolates from red fox and dog.

Toxocara canis isolates from dog and from red fox were compared in transmission trials and with molecular analysis using RAPD-PCR technique and comparison of the ITS2 sequence. After oral infection of bitches with 20,000 embryonated T. canis eggs of vulpine and canine origin, the vertical transmission to pup's was examined. All animals of both groups developed typical clinical symptoms of toxocarosis. The haematological, serological, parasitological and post mortem results showed no differences between both isolates except for the infectivity of T. canis stages in mice where the fox isolate showed a significant higher infectivity than the dog isolate. The RAPD-PCR showed a similarity coefficient of 0.95, similar to the range of intraspecific variation in Toxocara cati and Toxascaris leonina specimens as outgroups. The ITS2 comparison showed a 100% identity between both isolates with no intraspecific variations. Therefore, the study shows that the fox and the dog isolate of T. canis were identical in infectivity, transmission and molecular structure; a host adaptation could not be found and the fox has to be seen as a reservoir for T. canis infections in dogs. Considering the increasing number of foxes in urban areas the importance of helminth control in dogs is stressed.

Trichinella pseudospiralis: X-ray analysis of the infected muscle cells and the muscle larva compartments after exponential growth of the larva in situ.

The distribution of nutrients such as Na, Cl, K, P, S, and Ca was investigated by energy-dispersive X-ray microanalysis (EDXA) on bulk-frozen mouse muscles infected with Trichinella pseudospiralis. In an attempt to gain information as to whether muscle larvae would modify the element status within muscles of their host. Significant increases in phosphorus concentrations within nurse cells and internal cells of the larva, e.g., the somatic muscle cells and the stichocytes, were shown. This could reflect changes in the energy metabolism and/or in the turnover of nucleic acids of the nurse cell. High phosphorus concentrations within the internal larva cells corresponded to high levels of expression of thymidylate synthase shown elsewhere in both T. pseudospiralis and T. spiralis muscle larvae, most likely reflecting more intensive DNA replication. Furthermore, the Na+-concentration gradient between the nurse cell and neighboring host muscle cells indicated the plasma membrane as a diffusion barrier for Na+. Moreover, the cuticle seemed to maintain the Cl--concentration gradient between the nurse cell and the internal cells of the larva. Nevertheless, the mechanisms involved in the transport of both ions, the collagen cuticle appeared, strong permeability that serves the transcuticular transport maintaining the Cl--concentration gradient.

[Helminth fauna of red foxes (Vulpes vulpes LINNE 1758) in southern Saxony--2: Nematodes]. / Zur Helminthenfauna des Rotfuchses (Vulpes vulpes LINNE 1758) im Süden Sachsen-Anhalts--Teil 2: Nematoden.

Between January 1993 and November 1994 a total of 1300 red foxes from the administrative districts Halle and Dessau were examined for the presence of nematodes in the stomach and the small intestine. The following nematodes were found: Toxocara canis (26.5%), Toxascaris leonina (10.5%), Uncinaria stenocephala (15.9%) Ancylostoma caninum (1.7%). The search for Trichinella spp. larvae was negative in all 780 examined foxes.

[Helminth fauna of the red fox (Vulpes vulpes LINNE 1758) in south Sachsen-Anhalt--1: Cestodes]. / Zur Helminthenfauna des Rotfuchses (Vulpes vulpes LINNE 1758) im Süden Sachsen-Anhalts--Teil 1: Zestoden.

Between January 1993 and November 1994 a total of 1300 red foxes from the administrative districts Halle and Dessau were examined for the presence of Echinococcus multilocularis and other cestodes. Echinococcus multilocularis-infections were detected in only 4 of 1300 (0.3%) foxes. Furthermore the following cestodes were found: Mesocestoides spp. (54.1%), Taenia crassiceps (17.7%), Taenia polyacantha (11.9%), Hydatigera taeniaeformis (0.2%), Taenia serialis (0.15%), Taenia pisiformis (0.15%), not determinable taeniids (9.2%), Dipylidium caninum (0.2%) and Hymenolepis spp. (0.08%).

[Prevalence of Echinococcus multilocularis and other metacestodes and cestodes in the muskrat (Ondatra zibethicus LINK 1795) in Lower Saxony]. / Zur Prävalenz von Echinococcus multilocularis und anderen Metazestoden und Zestoden des Bisams (Ondatra zibethicus LINK 1795) in Niedersachsen.

Aim of the study was to examine the prevalence and regional distribution of Echinococcus multilocularis and other metacestodes and cestodes in muskrats in Lower Saxony, Germany. A total of 991 muskrats with similar numbers from all districts of the country were examined between January and December 1995. E. multilocularis metacestodes were found in 4.1% of the muskrats in the liver and other organs of the abdominal cavity. The majority of the E. multilocularis positive animals came from the south of Lower Saxony, where E. multilocularis is endemic, and single animals from the middle or the northern part of the country. All metacestodes found were fertile. Additionally, metacestodes from T. taeniaeformis were found in the livers of 42.3% of the muskrats, metacestodes from T. crassiceps were present in the abdominal cavity of 2.7%, T. polyacantha in 0.4% and T. martis in 3.4% of the animals. Adult cestodes of the family of the Anoplocephalidae were found in the small intestine of 1.5% of the muskrats. Due to autolysis a species differentiation of the latter was not possible.

[Nematode and trematode fauna of the muskrat (Ondatra zibethicus LINK, 1795) in Lower Saxony]. / Ein Beitrag zur Nematoden- und Trematodenfauna des Bisams (Ondatra zibethicus LINK, 1795) in Niedersachsen.

From January 1995 to December 1995, 991 muskrats were examined for the occurrence and the regional prevalence of nematodes and trematodes. The muskrats were trapped in all parts of Lower Saxony. 77.2% of the studied population were less than one year old, 22.8% were older. The male to female ratio was 54.5% to 45.5%. One genus of nematodes, Trichuris spp., was found in the colon in 1.9% of the animals in the south of the investigated area. A species differentiation was not possible, as exclusively female parasites had been found. Additionally, two genera of trematodes (Echinostoma spp. and Quinqueserialis quinqueserialis) belonging to two different families were detected in 2.5% of the muskrats. In the north of the investigated area the prevalence was significantly higher than in the south. As to the echinostomatides, no species-differentiation was made because, according to KANEV (1985), many echinostomatides have not been described correctly in the past. Some echinostomatides cannot be differentiated until today. There was no statistically significant correlation between parasite infections and sex of the animals. Concerning Echinostoma spp. and Quinqueserialis quinqueserialis, a highly significant correlation was found between the age of the muskrats and the trematode-infections. Young animals were infected more often than older animals, none of the younger animals was infected with Trichuris spp.

The efficacy of doramectin on arrested larvae of Ancylostoma caninum in early pregnancy of bitches.

The efficacy of doramectin treatment on arrested A. caninum larvae during early pregnancy of bitches was examined. Four bitches were percutaneously infected with 20,000 third-stage larvae of A. caninum on the day of conception and treated subcutaneously with 1 mg doramectin per kg body weight on day 30 of pregnancy. Four infected untreated pregnant bitches served as controls. A single application of dormectin substantially reduced the number of somatic larvae in bitches and the number of intestinal stages in bitches and puppies. However, it did not completely prevent lactogenic transmission of A. caninum larvae because five out of 23 puppies from three litters of the treated bitches harboured adult worms in their intestines, two of them shed eggs with the faeces. Although clinical disease did not occur in puppies from treated bitches the efficacy of the treatment was not satisfactory from an epidemiological point of view. Despite the treatment puppies with patent infections contaminated their environment with high numbers of eggs thus producing an intolerable infection risk for dogs and humans. No fetotoxic side-effects of the early treatment with doramectin were seen.

Immunochemical characterization of Ancylostoma caninum antigens.

Adult worms of Ancylostoma caninum were dissected and manually separated into cephalic glands, cervical glands, intestine, esophagus and cuticula. These fractions as well as third stage larvae were fractionated with Triton X-114 into water soluble (hydrophilic), Triton soluble (hydrophobic) and unsoluble proteins. These fractions were characterized by immunoblotting with serum from rabbits immunized either with a pool of cervical, cephalic glands and intestine, or the esophagus fraction as well as with sera from percutaneously infected dogs and rabbits. Immunodominant antigens were found that reacted with dog or rabbit post infection sera and could be suited as antigens in serodiagnostic tests. Hidden antigens were found in the several fractions. Those from esophagus and intestine could be vaccine candidates that will be tested in immunization trials.

[Comparative molecular biologic characterization of Dictyocaulus viviparus and Dictyocaulus eckerti]. / Vergleichende molekularbiologische Charakterisierung von Dictyocaulus viviparus und Dictyocaulus eckerti.

For a comparative characterization of the lungworm species D. viviparus and D. eckerti which is not generally accepted as a separate species, the restriction fragment length polymorphism (RFLP) of the PCR amplified ribosomal second internal transcribed spacer (ITS2) and their sequences of both species have been examined. Ribosomal ITS2 DNA was amplified from genomic DNA of individual worms using primer that correspond to the conserved 3' and 5' ends of the ITS2 flanking 5.8S and 28S regions of Caenorhabditis elegans. PCR products were digested with restriction endonucleases AluI, NspI, SspI, BclI and MseI and separated electrophoretically on a 1% agarose gel. Each restriction enzyme produced a species specific fragment length pattern. PCR products were cloned into pCRII and sequenced. The length of the ITS2 varied between 403 (D. viviparus) and 481 bases (D. eckerti) with a GC content ranged from 25 to 33%. Intraspecific variations were low (0-1.5%). Interspecific differences occur at 112 bases. The sequence homology between D. viviparus and D. eckerti was found with 76.7%. ITS2 sequence differences between D. viviparus and D. eckerti by far exceeded intraspecific variations. Therefore both methods showed distinct differences between the lungworm species examined, thus proving that D. eckerti is correctly described as a separate species. Both species occur in deer and specific primers have been designed for both species that will be used in prevalence studies to investigate the actual role of deer in the transmission of D. viviparus to cattle.

Investigations into the prevention of neonatal Toxocara canis infections in puppies by application of doramectin to the bitch.

The aim of this investigation was to examine whether the treatment of bitches with doramectin is able to prevent pre-natal and galactogenic infections with Toxocara canis in their pups. Five experimentally infected beagle bitches were treated subcutaneously with 1 mg doramectin per kg body weight on each of days 40 and 55 of their pregnancy. Another infected bitch served as an untreated control. The efficacy of the medication was examined by counting the intestinal stages and somatic larvae in bitches and pups. The treatment did not completely prevent perinatal infections with T. canis. Intestinal stages and/or somatic larvae occurred in 16 of 20 pups. Seven pups developed patent infections. Compared to the control pups, the average worm burden (intestinal stages) of pups from treated bitches was less than 1%. No impairment of condition or physical development was noticed in the pups during the investigations. From the second week of life, the pups of the non-medicated bitch showed signs of a severe toxocarosis. No side effects were seen in the bitches after treatment with doramectin.

Trichinella spiralis: X-ray analysis of the nurse cell-muscle larva complex after exponential growth of the larva.

The energy-dispersive X-ray analysis (EDXA) method was employed to determine how the exponential growth of the Trichinella spiralis larva affect the concentration of some metabolically active elements such as phosphorus, sulfur, sodium, chlorine, potassium, and calcium in host myocytes as well as inside the nurse cell-muscle larva complex. Two observations are noteworthy. First, the capsule of the complex reveals the highest Na+ and Cl-concentrations. We would suggest that these high Na+ and Cl-concentrations could be a part of the capsule-localized transport mechanisms covering the metabolic demands of the larva. Second, a substantial increase in the P concentration in the cells inside the complex, i.e., the nurse cell, somatic muscle of the larva, and larval stichosome was found. We postulate that energy metabolism in the nurse cell is entirely dependent on the metabolic requirements of the larva and that they remain together as one functional unit.

A study on the prevention of prenatal and galactogenic Toxocara canis infections in pups by treatment of infected bitches with ivermectin or doramectin.

Investigations were carried out to test the efficacy of a two dose treatment with ivermectin or doramectin on reactivated larvae of Toxocara canis in bitches to prevent prenatal and galactogenic infections of their pups. Thirty pregnant bitches were treated by subcutaneous injection of ivermectin or doramectin on day 40 and 50 post conception (p.c.) each with a dose of 1 mg/kg body weight. The efficacy of the treatments was determined by faecal examinations and by comparing the number of infected pups and the onset of patency in each group of pups. 1. Patient infections with T. canis were seen in pups from untreated bitches from day 21 after birth and all pups were coproscopically positive one week later. To prevent severe clinical symptoms all pups in this group were treated with anthelmintics on day 42 after birth. 2. Pups from ivermectin treated bitches occasionally exhibited patent infections from day 28 after birth onwards; pups from doramectin group exhibited infections from day 56 after birth. The number of patently infected pups in both groups increased till 70 days after birth, probably because of postnatal infections. 3. 28 days after parturition, T. canis infections became patent in all untreated bitches. Single bitches in the ivermectin and doramectin groups developed patent infections after day 49 after parturition. All coproscopically positive bitches had patently infected pups in their litters. 4. The contamination of the environment with eggs of T. canis was calculated from the results of the faecal examinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigations into the efficacy of doramectin on reactivated somatic larvae of Ancylostoma caninum Ercolani 1859 (Ancylostomatidae) in pregnant bitches.

The aim of this investigation was to examine whether reactivated somatic Ancylostoma caninum larvae can be eliminated by the administration of doramectin to pregnant bitches. Four pregnant bitches experimentally infected with 20,000 third-stage larvae of A. caninum were treated subcutaneously with 1 mg doramectin per kg body weight on day 55 of the pregnancy (5-8 days before parturition). Another four experimentally infected pregnant bitches served as controls. The single doramectin treatment completely prevented galactogenic infections in the puppies. Neither intestinal stages nor somatic larvae could be found. The administration of doramectin caused no local or generalized side-effects in the bitches. All 16 puppies of the treated bitches were born healthy and remained so during the whole trial period. Beginning during the third week after birth, all 20 puppies of the untreated bitches developed a severe microcytic, hypochromic anaemia. They had to be killed between 17 and 35 days after birth. Post mortem, they revealed a total of 8649 intestinal stages of A. caninum.

[The helminth fauna of red foxes (Vulpes vulpes LINNE 1758) in the administrative district of Karlsruhe. 2. Nematodes]. / Zur Helminthenfauna des Rotfuchses (Vulpes vulpes LINNE 1758) im Regierungsbezirk Karlsruhe. Teil 2: Nematoden.

Between February 1989 and January 1990 a total of 801 foxes were examined for the presence of nematodes in the stomach and the small intestine and 835 foxes for the presence of Trichinella spiralis larvae. The animals came from the german federal administration area of Karlsruhe. The following nematodes in order of frequency were found: Toxocara canis (30.2%), Uncinaria stenocephala (24.3%), Toxascaris leonina (2.0%) and Ancyclostoma caninum (1.1%). The investigation of the muscles of all animals for Trichinella spiralis was negative, however.

[The helminth fauna of the red fox (Vulpes vulpes LINNE 1758) in the administrative district of Karlsruhe. 1. Cestodes]. / Zur Helminthenfauna des Rotfuchses (Vulpes vulpes LINNE 1758) im Regierungsbezirk Karlsruhe. Teil 1: Zestoden.

Between February 1989 and January 1990 a total of 801 red foxes were examined for the presence of cestodes. Echinococcus multilocularis could be noted with an infection rate of 11.6% in the small intestine of the red fox. The following other cestodes were found (in order of frequency) Taenia crassiceps (19.9%), Mesocestoides spp. (16.6%), Taenia polyacantha (7.0%), Hydatigena taeniaeformis (0.7%), Dipylidium caninum (0.5%) and Diphyllobothrium latum (0.5%). Infections with Echinococcus multilocularis very often showed worm numbers between 11 and 100 specimen per fox. The number of worms of the other cestodes mostly varied between one and ten specimen per animal.

The behavior and pathogenicity of Toxacara canis larvae in mice of different strains.

In the present study the behavior and pathogenicity of second-stage larvae of Toxocara canis were examined in different mouse strains with special emphasis on the major histocompatibility complex (MHC). Mice of the inbred strains BALB, C3H, C57BL, and DBA and the outbred strain NMRI were infected orally with 1000 second-stage larvae of T. canis. The clinical behavior of the animals; the numbers of larvae detected in the liver, lungs, brain, and musculature; the hematological and serological parameters; and histological sections were examined. In mice of the BALB strain, no death occurred during the entire period of the investigation and the pattern of body-weight development of infected and uninfected animals was almost identical. The highest larval counts in the brain of all strains were found in BALB mice. The percentage of eosinophils in the blood of BALB mice increased after the 8th week postinfection, whereas it decreased in the other strains. Histological and pathophysiological changes developed to a lesser extent in this strain than in the other strains. In mice of the strains C3H, C57BL, DBA, and NMRI, deaths occurred from the 4th week postinfection onward. The infected animals lost weight in comparison with the uninfected controls; the number of larvae found in the brains of infected mice of the above-mentioned strains were lower than those detected in the BALB strain. There is no evidence that mechanical damage caused by migrating larvae in the brain tissue is mainly responsible for symptoms of central nervous toxocariasis. Likewise, the assumption that the MHC is involved in the allergic-inflammatory response in the brain could not be proven: infected mice of the BALB and DBA strains reacted completely differently, although both are equipped with the same MHC haplotype.

[Parasitological fecal studies of equids, dogs, cats and hedgehogs during the years 1984-1991]. / Ergebnisse parasitologischer Kotuntersuchungen von Equiden, Hunden, Katzen und Igeln der Jahre 1984-1991.

The results of the coproscopical examinations in horses, dogs, cats and hedgehogs between 1984 and 1991 are presented. In 9192 samples from horses 55.5% stages of strongylids, 4.0% of Parascaris equorum, 2.2% of anoplocephalids, 1.6% Strongyloides westeri, 0.7% of Oxyuris equi, 0.6% of Eimeria leuckarti, 0.2% of Fasciola hepatica and 0.04% of Dictyocaulus arnfieldi were found. In 48.0% of the 46 samples from donkeys eggs from strongylids were detected, in 17.4% larvae from Dictyocaulus arnfieldi, in 2.2% eggs from Strongyloides westeri, Parascaris equorum and oocysts from Eimeria leuckarti, respectively. In 3329 samples of dogs 6.9% developmental stages of Toxocara canis, 6.0% of Giardia spp., 4.2% of Isospora spp., 3.0% of Sarcocystis spp., 2.5% each of ancylostomids and Trichuris vulpis, 1.1% of Toxascaris leonina and 1.1% of Dipylidium canium, up to 1.0% of taeniids, 0.6% of each Mesocestoides spp. and Metastrongylidae, 0.3% of Strongyloides stercoralis and 0.2% of Capillaria spp. and Hammondia heydorni were detected. In 9.5% of the 1147 samples of cats eggs from Toxocara mystax were found, in 4.7% eggs of taeniids, in 4.6% cysts of Isospora spp., in 2.4% of Giardia spp., in 1.4% eggs of Dipylidium caninum, in 1.0% of Capillaria spp. and Aelurostrongylus abstrusus, in 0.6% development stages of Toxoplasma gondii, in 0.5% of ancylostomids and in 0.3% of Sarcocystis spp. and Opisthorchis felineus. In 1175 samples of hedgehogs 48.8% eggs of Capillaria spp., 35.9% of Crenosoma striatum, 17.9% oocysts of Isospora spp., 2.3% eggs of Brachylaemus erinacei were found.