Pathogenic potential of two sibling species, Anisakis simplex (s.s.) and Anisakis pegreffii (Nematoda: Anisakidae): in vitro and in vivo studies.

The pathogenic potentials of two sibling nematodes Anisakis simplex sensu stricto (s.s.) and A. pegreffii were compared by in vitro and in vivo studies. Live third-stage larvae of each species were subjected to agar blocks made using PBS or RPMI-1640, overlaid with different supernatants (artificial gastric juice, PBS, and RPMI-1640), and their penetration ability was compared. Their tolerance of artificial gastric juice was also tested. Further, they were introduced into rats by gastric intubation, and the in vivo locations of them were investigated. A. pegreffii showed higher penetration ability than A. simplex (s.s.) in most of the experimental conditions, except for the RPMI-1640 agar block overlaid with artificial gastric juice. In an acid tolerance test, the mean survival times were 6.1 days for A. simplex (s.s.) and 4.2 days for A. pegreffii. In an animal experiment, A. simplex (s.s.) stayed for a shorter time in the stomachs of rats than A. pegreffii. Some A. pegreffii and A. simplex (s.s.) were embedded in the gastric mucosa or freely existed in the abdominal cavity. All of these results suggest that A. pegreffii has the pathogenic potential to cause anisakidosis in humans when ingested, as does A. simplex (s.s.).

Detection of Cryptosporidium species in feces or gastric contents from snakes and lizards as determined by polymerase chain reaction analysis and partial sequencing of the 18S ribosomal RNA gene.

Cryptosporidiosis is a well-known gastrointestinal disease of snakes and lizards. In the current study, 672 samples (feces and/or gastric contents or regurgitated food items) of various snakes and lizards were examined for the presence of cryptosporidia by polymerase chain reaction (PCR) assay targeting a part of the 18S ribosomal RNA gene. A consecutive sequencing reaction was used to identify the cryptosporidian species present in PCR-positive samples. Cryptosporidium varanii (saurophilum) was detected in 17 out of 106 (16%) samples from corn snakes (Pantherophis guttatus) and in 32 out of 462 (7%) samples from leopard geckos (Eublepharis macularius). Cryptosporidium serpentis was found in 8 out of 462 (2%) leopard gecko samples, but in no other reptile. The Cryptosporidium sp. "lizard genotype" was present in 1 leopard gecko sample, and 1 sample from a corn snake showed a single nucleotide mismatch to this genotype. Pseudoparasitic cryptosporidian species were identified in 5 out of 174 (3%) ophidian samples, but not in lizards. Other sequences did not show complete similarity to previously published Cryptosporidium sequences. The results stress the importance for diagnostic methods to be specific for Cryptosporidium species especially in snakes and show a relatively high prevalence of C. varanii in leopard geckos and corn snakes.

In vivo and in vitro encystment of Echinochasmus liliputanus cercariae and biological activity of the metacercariae.

In vivo and in vitro encystment of the cercariae of Echinochasmus liliputanus and biological activity of the metacercariae were studied. In vivo encystment of cercariae occurred in the gills of goldfish, the second intermediate host. However, the cercariae also encysted in vitro in Locke solution (0.6x to 1.2x strength), 0.7-1.2% NaCI, artificial gastric juice, and human gastric juice. Locke or NaCI solutions were shown to be appropriate for in vitro encystment to occur within 24 hr; however, full-strength Locke solution was shown to be optimal. The 1-day-old metacercariae formed in vivo and treated in 0.1% sodium deoxycholate excystation medium at 37 C for 1 hr showed 88.5% excystation. The metacercariae formed in vitro, however, showed 88.6% and 85.0% excystation for normal and abnormal ones, respectively. Abnormal cysts at room temperature usually die within 10 days. About 70% of the normal cysts, both in vivo and in vitro, can still excyst after being stored in Locke 0.5x solution at 4 C for 3 mo. Cysts formed in vivo and in vitro were equally infective. The encystment of the cercariae in vitro could be inhibited when the cercariae were treated with 1 micromol silver nitrate. Because silver nitrate binds to the papillae, especially to the ciliated papillae, on the cercaria surface, it is suggested that papillary chemoreceptors may be involved in encystment of the cercariae. The finding of E. liliputanus cercariae encysting in vitro, especially in human gastric juice, might be helpful in elucidating mechanisms of the definitive hosts that are directly infected by the cercariae.

Analysis of first gastric compartment fluid collected via percutaneous paracentesis from healthy llamas.

OBJECTIVE: To evaluate the safety and efficacy of percutaneous paracentesis for fluid collection from the first gastric compartment of healthy llamas and to describe characteristics of that fluid. DESIGN: Prospective study. ANIMALS: 10 healthy adult llamas. PROCEDURE: Physical examinations were performed prior to sample collection and for 14 days afterwards. A CBC was performed prior to sample collection and 5 days later. A 16-gauge, 7.5-cm stainless steel needle, positioned approximately 20 cm caudal to the costochondral junction of the last rib, was pointed in a dorsocraniomedial direction and pushed through the abdominal wall into the lumen of the first gastric compartment. Fluid was aspirated and analyzed immediately for color, odor, consistency, pH, methylene blue reduction (MBR) time, protozoa, and bacteria. RESULTS: Fluid samples were obtained from 9 of 10 llamas. Mean volume was 4.1 ml, mean pH was 6.67, and mean MBR time was 173 seconds. Odor was slightly acidic, color was light brown-green to light yellow-green, and consistency was moderate. Small protozoa with variable iodine staining and gram-negative bacteria were commonly detected. With few exceptions, results of physical examinations and CBC remained within reference ranges. CLINICAL IMPLICATIONS: Fluid samples from the first gastric compartment can be successfully obtained by percutaneous paracentesis. Fluid characteristics were similar to those of fluid collected via orogastric tube in llamas and cattle.

[Effect of cobalt and vitamin B 12 on growth and survival of rumen ciliates in vitro as a function of bacterial population]. / Influence du cobalt et de la vitamine B12 sur la croissance et la survie des ciliés du rumen in vitro, en fonction de la population bactérienne.

The effect of inorganic cobalt or organic cobalt in the form of vitamin B12 was studied on the growth of rumen ciliates in the presence of normal bacterial population and in the presence of reduced bacterial population. It was stated that concentration from 0.1 to 1 cobalt microgram/ml and 0.12 to 0.24 vitamin B12 microgram/ml stimulated growth of rumen ciliates. At rates 10 to 20 times weaker, cobalt in the form of vitamin B12 was more active than cobalt in inorganic form. With reduced bacterial population (10(3) B/ml) protozoa died within a few days but their survival was prolonged by adding cobalt, this effect being more pronounced with vitamin B12 than with inorganic cobalt. The growth of ciliates treated with antibiotics was stimulated by addition of bacteria, and this effect was more pronounced when the bacteria had been preincubated with cobalt. Incorporation of cobalt into rumen ciliates was studied using electron microprobe analysis. Cobalt was present in all the ciliate but essentially accumulated as granules in the endoplasm inside or outside the vacuoles. With reduced bacterial population, cobalt was also incorporated into the ciliates whatever the Co concentration. Indeed, ciliates seemed to need bacteria in order to use the organic cobalt for growth.

Castle's test (with vitamin B12 and normal gastric juice) in the ileum in patients with genuine and patients with tapeworm pernicious anaemia.

A mixture of vitamin B12 and normal gastric juice, instilled through an intestinal tube into the ileum, produces haematological remission in patients with tapeworm pernicious anaemia. When a similar mixture is administered by mouth, this effect fails to occur. This observation constitutes evidence in favour of the view that Diphyllobothrium latum, attached to the proximal portion (jejunum) of the intestine, absorbs the vitamin B12 contained in the food, thus preventing vitamin bound to the intrinsic factor of the gastric juice from reaching the receptors in the distal portions of the small intestine of the host. In genuine pernicious anaemia, remission results from the administration of vitamin B12+gastric juice both by mouth and into the ileum.

Prevalence of Giardiasis: a study at upper-gastrointestinal endoscopy.

The prevalence of giardiasis was assessed in 1000 consecutive adult patients undergoing upper-gastrointestinal endoscopy for the usually accepted indications. Patients with upper-gastrointestinal bleeding were excluded. The diagnosis was established by examination of duodenal aspirate and duodenal mucosal impression smears. In 21 patients (2.1%) trophozoites were detected both in the duodenal juice and stained mucosal impression smears. All were treated with metronidazole or tinidazole. In 14 of 16 patients who had subsequent duodenal intubation, eradication of the parasite was confirmed. In five patients previously existent abdominal pain disappeared with clearing of the parasite, and no other cause for their abdominal pain was discovered. A search for Giardia lamblia infestation may be a worthwhile additional procedure at the time of endoscopy when no other cause for abdominal pain is found.