Eruption-triggered avalanche, flood, and lahar at mount st. Helens--effects of winter snowpack.

An explosive eruption of Mount St. Helens on 19 March 1982 had substantial impact beyond the vent because hot eruption products interacted with a thick snowpack. A blast of hot pumice, dome rocks, and gas dislodged crater-wall snow that avalanched through the crater and down the north flank. Snow in the crater swiftly melted to form a transient lake, from which a destructive flood and lahar swept down the north flank and the North Fork Toutle River.

Outbreak of listeria meningoencephalitis in young lambs.

An outbreak of listeriosis occurred in five-week-old lambs in a flock of 200 Dorset ewes and 240 lambs in-wintered. Nine lambs were lost within a period of 10 days. No cases of stillbirth or abortion or cerebral listeriosis occurred in the ewes. Silage had been fed on this farm to both cattle and sheep for 10 years without any previous problems. A description of the outbreak and the findings are reported.

The isolation of Haemophilus somnus following sudden deaths in suckler calves in Scotland.

A blood or yeast dependent pleomorphic Gram-negative bacillus was isolated from the pneumonic lung of a suckled calf which died suddenly. The organism was biochemically similar to American strains of Haemophilus somnus and was shown to be serologically similar by rapid slide agglutination, tube agglutination and micro-complement fixation tests. The possible importance of this organism in disease syndromes in cattle in the United Kingdom is discussed.

Hepatic lipodystrophy of pedigree Galloway calves.

Hepatic lipodystrophy has been recognised in pedigree Galloway calves since 1965. Between 1975 and 1984 15 cases from five farms were examined. The calves initially appear normal and in good bodily condition but invariably die by five months of age. The characteristic clinical and neurological changes lead to body tremors, opisthotonus, and dyspnoea before the animals become recumbent and die. On postmortem examination the most significant finding in all cases was an enlarged, pale and mottled liver weighing up to 2.75 kg. Limited histopathological examinations of the brain and liver revealed changes suggestive of hepatic encephalopathy. Exhaustive investigations of the farms failed to reveal any significant findings and the small number of cases made it impossible to determine whether the disease was genetically determined; limited evidence suggests that a 'storage disease' cannot be excluded.

Tick borne fever in association with mucosal disease and cobalt deficiency in calves.

Tick borne fever is considered to have played a major role in a complex disease syndrome involving mucosal disease and cobalt deficiency in a group of young calves reared on an upland farm in South West Scotland. Anaemia, illthrift, coat colour changes and scour were the main clinical signs.

Outbreak of monensin poisoning in cattle.

Following accidental overdosage with monensin, nine deaths occurred in a batch of 40, four-to-seven-month-old calves. A description of the incident is given including the findings on post mortem examination. Inaccurate on-farm feed mixing can present problems as was highlighted by this outbreak.