Retrospective study of 108 foals with septic osteomyelitis.

OBJECTIVE: To determine the clinical characteristics, short-term outcome and future athletic performance of foals with septic osteomyelitis. DESIGN: Retrospective clinical study of 108 Thoroughbred foals with radiographic evidence of bone infection that were presented at the Scone Veterinary Hospital between August 1995 and December 2001. Medical records were reviewed and information concerning signalment, the clinical, laboratory and radiographic findings, treatment and outcome was obtained. Racing records were obtained and evaluated for surviving foals that had reached racing age. RESULTS: Mean age of foals at initial evaluation was 39 days (range 1-180 days); 21 foals had multiple radiographic bone lesions (19.4%), and 76 had concurrent septic arthritis (70.4%). The most frequently affected bones were the femur, tibia and distal phalanx. In total, 87 foals were discharged from the hospital (80.6%), 79 survived long-term to reach racing age and 52 raced (65.8%). Overall, 48% (52/108) of the foals treated for osteomyelitis raced. Foals less than 30 days of age at the time of diagnosis, critically ill foals and those with multiple bones or joints affected were significantly less likely to be discharged from hospital. Multiple septic joints, but not multiple bone involvement, had an unfavourable prognosis for racing. CONCLUSIONS: The prognosis for survival of foals with septic osteomyelitis or osteitis is favourable. Multiple bone or joint involvement is an important short-term prognostic indicator; however, the involvement of multiple joints, but not multiple infected bones, is associated with an unfavourable prognosis for racing.

Sensory neuroanatomy of a skin-penetrating nematode parasite Strongyloides stercoralis. II. Labial and cephalic neurons.

Host recognition, contact, and skin-penetration by Strongyloides stercoralis infective larvae are crucially important behavioral functions mediating transition from free-living to parasitic life. The sensilla of the worm's anterior tip presumably play an important role in these processes. Besides the main chemosensilla, the amphids, which are of central importance, the larva has 16 putative mechanosensilla. There are six inner labial sensilla: two dorsal, two ventral, and two lateral. The two dorsal and ventral pairs are each innervated by two neurons, whereas each lateral sensillum is singly innervated. The six outer labial and four cephalic sensilla are all singly innervated. All of these have the characteristics of mechanoreceptors: they are closed to the external environment, and closely associated with the overlying cuticle. Distally, their dendritic processes contain granular material and associated microtubules. With two exceptions, the relevant neuronal cell bodies lie in lateral ganglia adjacent to the nerve ring, their positions remarkably similar to those of their homologues in the free-living nematode, Caenorhabditis elegans. Cell bodies of two neuronal pairs, one of two dorsal inner labial neurons and one of two ventral inner labial neurons per side, are however, found far anterior to the remaining cell bodies. All labial and cephalic sensilla are apparently mechanoreceptors, complementing the well-developed chemosensilla. Presumably infective larvae require touch and stretch receptors, not only to initiate skin penetration by finding irregularities as points of access, but also to bore through tissue to reach their ultimate enteral destination.

Sensory neuroanatomy of a skin-penetrating nematode parasite: Strongyloides stercoralis. I. Amphidial neurons.

The Strongyloides stercoralis infective larva resumes feeding and development on receipt of signals, presumably chemical, from a host. Only two of the anterior sense organs of this larva are open to the external environment. These large, paired goblet-shaped sensilla, known as amphids, are presumably, therefore, the only chemoreceptors. Using three-dimensional reconstructions made from serial electron micrographs, amphidial structure was investigated. In each amphid, cilialike dendritic processes of 11 neurons extend nearly to the amphidial pore; a twelfth terminates at the base of the amphidial channel, behind an array of lateral projections on the other processes. A specialized dendritic process leaves the amphidial channel and forms a complex of lamellae that interdigitate with lamellae of the amphidial sheath cell. This "lamellar cell" is similar to one of the "wing cells" or possibly the "finger cell" of Caenorhabditis elegans. Each of the 13 amphidial neurons was traced to its cell body. Ten neurons, including the lamellar cell, connect to cell bodies in the lateral ganglion, posterior to the nerve ring. The positions of these cell bodies were similar to those of the amphidial cell bodies in C.elegans. Therefore, they were named by using C. elegans nomenclature. Three other amphidial processes connect to cell bodies anterior to the nerve ring; these have no homologs in C. elegans. A map allowing identification of the amphidial cell bodies in the living worm was prepared. Consequently, laser ablation studies can be conducted to determine which neurons are involved in the infective process.

Effects of time, from collection to processing, on the recovery of Haemonchus contortus third-stage larvae from herbage.

Being able to obtain accurate estimates for the number of Haemonchus contortus third-stage larvae (L3) on pasture is essential to any type of strategy intended for control. The objective of this experiment was to study the effect of the time, from collection to processing, on the recovery rate of H. contortus L3 from herbage. Separate herbage samples were inoculated with two treatments of a known amount of larvae on Day 1 and then samples were processed from Day 1 to Day 30. This simulated infective herbage was collected, refrigerated, and processed over a period of 1 month. A drop in the recovery rate over time was found. Treatment 2 (5000 L3) exhibited a sharper decline in recovery rate than Treatment 1 (1800 L3). These findings suggest that the effect of time, from collection to processing, as well as larval concentration on the herbage, must be considered when performing any type of larval recovery technique.